Papers for Thursday, Feb 10 2022

We present constraints on cosmological parameters from the Pantheon+ analysis of 1701 light curves of 1550 distinct Type Ia supernovae (SNe Ia) ranging in redshift from $z=0.001$ to 2.26. This work features an increased sample size, increased redshift span, and improved treatment of systematic uncertainties in comparison to the original Pantheon analysis and results in a factor of two improvement in cosmological constraining power. For a Flat$\Lambda$CDM model, we find $\Omega_M=0.338\pm0.018$ from SNe Ia alone. For a Flat$w_0$CDM model, we measure $w_0=-0.89\pm0.13$ from SNe Ia alone, H$_0=72.86^{+0.94}_{-1.06}$ km s$^{-1}$ Mpc$^{-1}$ when including the Cepheid host distances and covariance (SH0ES), and $w_0=-0.978^{+0.024}_{-0.031}$ when combining the SN likelihood with constraints from the cosmic microwave background (CMB) and baryon acoustic oscillations (BAO); both $w_0$ values are consistent with a cosmological constant. We also present the most precise measurements to date on the evolution of dark energy in a Flat$w_0w_a$CDM universe, and measure $w_a=-0.4^{+1.0}_{-1.8}$ from Pantheon+ alone, H$_0=73.40^{+0.99}_{-1.22}$ km s$^{-1}$ Mpc$^{-1}$ when including SH0ES, and $w_a=-0.65^{+0.28}_{-0.32}$ when combining Pantheon+ with CMB and BAO data. Finally, we find that systematic uncertainties in the use of SNe Ia along the distance ladder comprise less than one third of the total uncertainty in the measurement of H$_0$ and cannot explain the present "Hubble tension" between local measurements and early-Universe predictions from the cosmological model.

Studying galaxies at different cosmic epochs entails several observational effects that need to be taken into account to compare populations across a large time span in a consistent manner. We use a sample of 166 nearby galaxies that hosted type Ia supernovae (SNe Ia) and have been observed with the integral field spectrograph MUSE through the AMUSING survey. Here, we present a study of the systematic errors and bias in the host stellar mass with increasing redshifts that are generally overlooked in SNe Ia cosmological analyses. We simulate observations at different redshifts (0.1<z<2.0) using four photometric bands (griz, similar to the Dark Energy Survey-SN program) to then estimate the host galaxy properties across cosmic time. We find that stellar masses are systematically underestimated as we move towards higher redshifts, due mostly to different rest-frame wavelength coverage, with differences reaching 0.3 dex at z~1. We have used the newly derived corrections as a function of redshift to correct the stellar masses of a known sample of SN Ia hosts and derive cosmological parameters. We show that these corrections have a small impact on the derived cosmological parameters. The most affected is the value of the mass step $\Delta_M$, which is reduced by $\sim$0.004 (6% lower). The dark energy equation of state parameter $w$ changes by $\Delta w \sim $0.006 (0.6% higher) and the value of $\Omega_m$ increases at most by 0.001 ($\sim$0.3%), all within the derived uncertainties of the model. While the systematic error found in the estimate of the host stellar mass does not significantly affect the derived cosmological parameters, it is an important source of a systematic error that one should correct for as we enter a new era of precision cosmology.

The [CII]$_{158\mu m}$ line has long been proposed as a promising line to spectroscopically confirm galaxies in the epoch of reionization. In this paper we present the results of new ALMA observations spectral scanning for [CII] in six particularly luminous Lyman Break Galaxies at $z\sim7$. The six sources were drawn from a sample of bright $z\sim7$ galaxies identified using the wide-area optical, near-IR, and Spitzer/IRAC data over the COSMOS/UltraVISTA field and were targeted on the basis of tight constraints on their redshifts from their IRAC [3.6]-[4.5] colors. We detect significant ($>9\sigma$) [CII] lines in three of our six targets ($50\%$) co-spatial with the rest-$UV$ emission from the ground/space-based near-IR imaging. The luminosities of the [CII] lines lie in the range $5.6$ to $8.8\times10^{8}L_{\odot}$, consistent with the local [CII]-SFR relation. Meanwhile, their [CII]/$L_{IR}\sim1-3\times10^{-3}$ ratios are slightly elevated compared to local (U)LIRGS. This could be due to lower dust-to-gas or dust-to-metal ratios. We also find that our sources display a large kinematic diversity, with one source showing signs of rotation, one source a likely major merger and one dispersion dominated source that might contain a bright star-forming clump. Our results highlight the effectiveness of spectral scans with ALMA in spectroscopically confirming luminous galaxies in the epoch of reionization, something that is being be applied on a significantly larger sample in the on-going REBELS large program.

We investigate the burstiness of star formation and the ionizing efficiency of a large sample of galaxies at $0.7 < z < 1.5$ using HST grism spectroscopy and deep ultraviolet (UV) imaging in the GOODS-N and GOODS-S fields. The star formation history (SFH) in these strong emission line low-mass galaxies indicates an elevated star formation rate (SFR) based on the H$\alpha$ emission line at a given stellar mass when compared to the standard main sequence. Moreover, when comparing the H$\alpha$ and UV SFR indicators, we find that an excess in SFR(H$\alpha$) compared to SFR(UV) is preferentially observed in lower-mass galaxies below $10^{9}$ M$\odot$, which are also the highest-EW galaxies. These findings suggest that the burstiness parameters of these strong emission line galaxies may differ from those inferred from hydrodynamical simulations and previous observations. For instance, a larger burstiness duty cycle would explain the observed SFR(H$\alpha$) excess. We also estimate the ionizing photon production efficiency $\xi_{ion}$, finding a median value of Log($\xi_{ion}$/erg$^{-1}$ Hz)$=24.80 \pm 0.26$ when adopting a Galactic dust correction for H$\alpha$ and an SMC one for the stellar component. We observe an increase of $\xi_{ion}$ with redshift, further confirming similar results at higher redshifts. We also find that $\xi_{ion}$ is strongly correlated with EW(H$\alpha$), which provides an approach for deriving $\xi_{ion}$ in early galaxies. Lower-mass, lower-luminosity galaxies have a higher $\xi_{ion}$. Overall, these results provide further support for faint galaxies playing a major role in the reionization of the Universe.

We present the MaNGA FIREFLY Value-Added-Catalogue (VAC) - a catalogue of ~3.7 million spatially resolved stellar population properties across 10,010 nearby galaxies from the final data release of the MaNGA survey. The full spectral fitting code FIREFLY is employed to derive parameters such as stellar ages, metallicities, stellar and remnant masses, star formation histories and dust attenuation. In addition to Voronoi-binned measurements, our VAC also provides global properties, such as central values and radial gradients. Two variants of the VAC are available: presenting the results from fits using the M11-MILES and the novel MaStar stellar population models. MaStar allows to constrain the fit over the whole MaNGA wavelength range, extends the age-metallicity parameter space, and uses empirical spectra from the same instrument as MaNGA. The fits employing MaStar models find on average slightly younger ages, higher mass-weighted metallicities and smaller colour excesses. These differences are reduced when matching wavelength range and converging template grids. We further report that FIREFLY stellar masses are systematically lower by ~0.3 dex than masses from the MaNGA PCA and Pipe3D VACs, but match masses from the NSA best with only ~0.1 dex difference. Finally, we show that FIREFLY stellar ages correlate with spectral index age indicators H$\delta_A$ and $D_n$(4000), though with a clear additional metallicity dependence.

Emission and absorption lines from elements heavier than helium (metals) represent one of our strongest probes of galaxy formation physics across nearly all redshifts accessible to observations. The vast majority of simulations that model these metal lines often assume either collisional or photoionisation equilibrium, or a combination of the two. For the few simulations that have relaxed these assumptions, a redshift-dependent meta-galactic UV background or fixed spectrum is often used in the non-equilibrium photoionisation calculation, which is unlikely to be accurate in the interstellar medium where the gas can self-shield as well as in the high-redshift circumgalactic medium where locally emitted radiation may dominate over the UV background. In this work, we relax this final assumption by coupling the ionisation states of individual metals to the radiation hydrodynamics solver present in RAMSES-RT. Our chemical network follows radiative recombination, dielectronic recombination, collisional ionisation, photoionisation, and charge transfer and we use the ionisation states to compute non-equilibrium optically-thin metal-line cooling. The fiducial model solves for the ionisation states of C, N, O, Mg, Si, S, Fe, and Ne in addition to H, He, and H$_2$, but can be easily extended for other ions. We provide interfaces to two different ODE solvers that are competitive in both speed and accuracy. The code has been benchmarked across a variety of gas conditions to reproduce results from CLOUDY when equilibrium is reached. We show an example isolated galaxy simulation with on-the-fly radiative transfer that demonstrates the utility of our code for translating between simulations and observations without the use of idealised photoionisation models.

Context: The radial variations of the stellar populations properties within passive galaxies at high redshift contain information about their assembly mechanisms, based on which galaxy formation and evolution scenarios may be distinguished. Aims: The aim of this work is to give constraints on massive galaxy formation scenarios through one of the first analyses of age and metallicity gradients of the stellar populations in a sample of passive galaxies at $z > 1.6$ based on spectroscopic data from the Hubble Space Telescope. Methods: We combined G$141$ deep slitless spectroscopic data and F$160$W photometric data of the spectroscopically passive galaxies at $1.6< z < 2.4$ with $H_{160} < 22.0$ in the field of view of the cluster JKCS $041$. We extracted spectra from different zones of the galaxies, and we analysed them by fitting them with a library of synthetic templates of stellar population models to obtain estimates of the age and metallicity gradients. Results: We obtained reliable measurements of age and metallicity parameters in different spatial zones of $\text{four}$ galaxies. We performed spatially resolved measurements in individual high-redshift galaxies without the need of peculiar situations (i.e. gravitational lensing) for the first time. All four galaxies exhibit negative metallicity gradients. Their amplitude, similar to that measured in galaxies in the local Universe, suggests that the stellar populations of passive galaxies from $z \sim 2$ to $z = 0$ are not redistributed. Conclusions: Although the sample we analysed is small, the results we obtained suggest that the main mechanism that determines the spatial distribution of the stellar population properties within passive galaxies is constrained in the first $3$ Gyr of the Universe. This is consistent with the revised monolithic scenario.

We present a study designed to measure the average LyC escape fraction ($\langle f_{\rm esc}\rangle$) of star-forming galaxies at z=3.5. We assemble a sample of 148 galaxies from the VANDELS survey at $3.35\leq z_{\rm spec}\leq3.95$, selected to minimize line-of-sight contamination of their photometry. For this sample, we use ultra-deep, ground-based, $U-$band imaging and HST $V-$band imaging to robustly measure the distribution of $\mathcal{R_{\rm obs}}$ $=(L_{\rm LyC}/L_{\rm UV})_{\rm obs}$. We then model the distribution as a function of $\langle f_{\rm esc}\rangle$, carefully accounting for attenuation by dust, and the IGM (and CGM). A maximum likelihood fit to the $\mathcal{R_{\rm obs}}$ distribution returns a best-fitting value of $\langle f_{\rm esc}\rangle =0.07\pm0.02$, a result confirmed using an alternative Bayesian inference technique (both exclude $\langle f_{\rm esc}\rangle=0.0$ at $> 3\sigma$). By splitting our sample in two, we find evidence that $\langle f_{\rm esc}\rangle$ is positively correlated with Ly$\alpha$ equivalent width, with high and low sub-samples returning best fits of $\langle f_{\rm esc}\rangle=0.12^{+0.06}_{-0.04}$ and $\langle f_{\rm esc} \rangle=0.02^{+0.02}_{-0.01}$, respectively. In contrast, we find evidence that $\langle f_{\rm esc}\rangle$ is anti-correlated with intrinsic UV luminosity and UV dust attenuation; with low UV luminosity and dust attenuation sub-samples returning best fits in the range $0.10 \leq \langle f_{\rm esc}\rangle \leq 0.22$. We do not find evidence for a clear correlation between $f_{\rm esc}$ and galaxy stellar mass, suggesting it is not a primary indicator of leakage. Although larger samples are needed to robustly confirm these trends, they suggest that it is entirely plausible that the low dust and metallicity galaxies found at z > 6 will display the $\langle f_{\rm esc}\rangle\geq0.1$ required to drive reionization.

Current and upcoming high angular resolution and multi-frequency experiments are well poised to explore the rich landscape of secondary CMB anisotropies. In this context, we compute for the first time, the power spectrum of CMB fluctuations from plasma in a cosmological distribution of evolving lobes of giant radio galaxies. We, also, explicitly take into account the non-thermal electron distribution, as opposed to thermal distribution, which has important implications for the inference of the CMB angular power spectrum. The relativistic particles are fed from the central supermassive blackholes via radio jets leading to radio lobes expanding to megaparsec scales into the intergalactic medium. Using a model of radio galaxy, we model the energetics and the pressure of the non-thermal electrons. We calculate the mean global non-thermal y-distortion, \ynt. For observationally reasonable distribution of the jet luminosities in the range of $10^{45}-10^{47}$ ergs$^{-1}$, we find \ynt to be less than $10^{-5}$, and hence not violating the COBE limit as previously claimed. Using the unique spectral dependence of the non-thermal SZ, we show that a detection of \ynt can be within reach at the level of $\gtrsim 5\sigma$ from a future PIXIE-like experiment. The total non-thermal SZ power spectrum, $C^{NT}_\ell$, from the radio lobes is shown to peak at $\ell \sim 3000$ with an amplitude $\sim 1\%$ of thermal SZ power spectrum from galaxy clusters, and is also within the reach for a PIXIE like experiment. Finally, we show that a detection of the $C^{NT}_\ell$ with a PIXIE-like experiment can lead to $\sim 5\sigma$ constraint on the mass dependence of the jet luminosity with the constraint becoming, at least, ten times better for the proposed more ambitious CMB-HD survey. This will, further, lead to the tightest constraint on the central black hole mass -to- host halo mass scaling relations.

The power spectrum of weak lensing fluctuations has a non-Gaussian distribution due to its quadratic nature. On small scales the Central Limit Theorem acts to Gaussianize this distribution but non-Gaussianity in the signal due to gravitational collapse is increasing and the functional form of the likelihood is unclear. Analyses have traditionally assumed a Gaussian likelihood with non-linearity incorporated into the covariance matrix; here we provide the theory underpinning this assumption. We calculate, for the first time, the leading-order correction to the distribution of angular power spectra from non-Gaussianity in the underlying signal and study the transition to Gaussianity. Our expressions are valid for an arbitrary number of correlated maps and correct the Wishart distribution in the presence of weak (but otherwise arbitrary) non-Gaussianity in the signal. Surprisingly, the resulting distribution is not equivalent to an Edgeworth expansion. The leading-order effect is to broaden the covariance matrix by the usual trispectrum term, with residual skewness sourced by the trispectrum and the square of the bispectrum. Using lognormal lensing maps we demonstrate that our likelihood is uniquely able to model both large and mildly non-linear scales. We provide easy-to-compute statistics to quantify the size of the non-Gaussian corrections. We show that the full non-Gaussian likelihood can be accurately modelled as a Gaussian on small, non-linear scales. On large angular scales non-linearity in the lensing signal imparts a negligible correction to the likelihood, which takes the Wishart form in the full-sky case. Our formalism is equally applicable to any kind of projected field.

We present a survey of the central region of the nearest starburst galaxy, IC 10, using the W. M. Keck Observatory Keck Cosmic Web Imager (KCWI) at high spectral and spatial resolution. We map the central starburst of IC 10 to sample the kinematic and ionization properties of the individual star-forming regions. Using the low spectral resolution mode of KCWI we map the oxygen abundance and with the high spectral resolution mode we identify 46 individual H II regions. These H II regions have an average radius of 4.0 pc, star formation rate $\sim1.3\times10^{-4}$ M$_\odot$ yr$^{-1}$, and velocity dispersion $\sim$16 km s$^{-1}$. None of the H II regions appear to be virialized ($\rm \alpha_{vir}>>1$), and, on average, they show evidence of ongoing expansion. IC 10's H II regions are offset from the star forming region size-luminosity scaling relationships, as well as Larson's Law that relates size and velocity dispersion. We investigate the balance of inward and outward pressure, $\rm P_{in}$ and $\rm P_{out}$, finding $\rm P_{out}>P_{in}$ in 89% of H II regions, indicating feedback driven expansion even in these low mass H II regions. We find warm gas pressure ($\rm P_{gas}$) provides the dominant contribution to the outward pressure ($\rm P_{out}$). This counteracts the inward pressure which is dominated by turbulence in the surrounding gas rather than self-gravity. Five H II regions show evidence of outflows which are most likely supported by either stellar winds (2 regions) or champagne flows (3 regions). These observations provide new insights into the state of the star-forming regions in IC 10 and negative feedback from low mass clusters.

We present SIBELIUS-DARK, a constrained realisation simulation of the local volume to a distance of 200~Mpc from the Milky Way. SIBELIUS-DARK is the first study of the \textit{Simulations Beyond The Local Universe} (SIBELIUS) project, which has the goal of embedding a model Local Group-like system within the correct cosmic environment. The simulation is dark-matter-only, with the galaxy population calculated using the semi-analytic model of galaxy formation, GALFORM. We demonstrate that the large-scale structure that emerges from the SIBELIUS constrained initial conditions matches well the observational data. The inferred galaxy population of SIBELIUS-DARK also match well the observational data, both statistically for the whole volume and on an object-by-object basis for the most massive clusters. For example, the $K$-band number counts across the whole sky, and when divided between the northern and southern Galactic hemispheres, are well reproduced by SIBELIUS-DARK. We find that the local volume is somewhat unusual in the wider context of $\Lambda$CDM: it contains an abnormally high number of supermassive clusters, as well as an overall large-scale underdensity at the level of $\approx 5$\% relative to the cosmic mean. However, whilst rare, the extent of these peculiarities does not significantly challenge the $\Lambda$CDM model. SIBELIUS-DARK is the most comprehensive constrained realisation simulation of the local volume to date, and with this paper we publicly release the halo and galaxy catalogues at $z=0$, which we hope will be useful to the wider astronomy community.

The Central Molecular Zone (CMZ) contains most of the mass of our Galaxy but its star formation rate is one order of magnitude lower than in the Galactic disc. This is likely related to the fact that the bulk of the gas in the CMZ is in a warm ($>$100 K) and turbulent phase with little material in the pre-stellar phase. We present in this Letter observations of deuterium fractionation (D/H ratios) of HCN, HNC, HCO$^{+}$, and N$_{2}$H$^{+}$ towards the CMZ molecular cloud G+0.693-0.027. These observations clearly show, for the first time, the presence of a colder, denser, and less turbulent narrow component, with a line width of $\sim$9 km s$^{-1}$, in addition to the warm, less dense and turbulent broad component with a line width of $\sim$20 km s$^{-1}$. The very low D/H ratio $\le$6$\times$10$^{-5}$ for HCO$^{+}$ and N$_{2}$H$^{+}$, close to the cosmic value ($\sim$2.5$\times$10$^{-5}$), and the high D/H ratios $>$4$\times$10$^{-4}$ for HCN and HNC derived for the broad component, confirm the presence of high-temperatures deuteration routes for nitriles. For the narrow component we have derived D/H ratios $>$10$^{-4}$ and excitation temperatures of $7$ K for all molecules, suggesting kinetic temperatures $\le$30 K and H$_2$ densities $\ge$5$\times$10$^{4}$ cm$^{-3}$, at least one order of magnitude larger than for the broad component. The method presented in this Letter allows to identify clouds on the verge of star formation, i.e. under pre-stellar conditions, towards the CMZ. This method can also be used for the identification of such clouds in external galaxies.

The discovery probability of long-period comets (LPCs) passing near the Sun is highest during their first passage and then declines, or fades, during subsequent return passages. Comet fading is largely attributed to devolatilization and fragmentation via thermal processing within 2-3 AU of the Sun (1 AU being the Earth-Sun distance). Here our numerical simulations show that comet observing campaigns miss vast numbers of LPCs making returning passages through the Saturn region (near 10 AU) because these comets fade during prior, even more distant passages exterior to Saturn and thus elude detection. Consequently, comet properties significantly evolve at solar distances much larger than previously considered, and this offers new insights into the physical and dynamical properties of LPCs, both near and far from Earth.

The role played by environment in galaxy evolution is a current debate in astronomy. The degree to which environment can alter, re-shape, or drive galaxy evolution is a topic of discussion in both fronts, observations and simulations. This paper analyses the gas metallicity gradients for a sample of 10 Fornax cluster galaxies observed with MUSE as part of the Fornax3D project. Detailed maps of emission lines allowed a precise determination of gas metallicity and metallicity gradients. The integrated gas metallicity of our Fornax cluster galaxies show slightly higher metallicities (~0.045 dex) in comparison to a control sample. In addition, we find signs of a mass and metallicity segregation from the center to the outskirts of the cluster. By comparing our Fornax cluster metallicity gradients with a control sample we find a general median offset of ~0.04 dex/Re, with 8 of our galaxies showing flatter or more positive gradients. We find no systematic difference between the gradients of recent and intermediate infallers when considering the projected distance of each galaxy to the cluster center. To identify the origin of the observed offset in the metallicity gradients, we perform a similar analysis with data from the TNG50 simulation. We identify 12 subhalos in Fornax-like clusters and compare their metallicity gradients with a control sample of field subhalos. This exercise also shows a flattening in the metallicity gradients for galaxies in Fornax-like halos, with a median offset of ~0.05 dex/Re We also analyse the merger history, Mach numbers (M), and ram pressure stripping of our TNG50 sample. We conclude that the observed flattening in metallicity gradients is likely due to a combination of galaxies traveling at supersonic velocities (M>1) that are experiencing high ram pressure stripping and flybys.

As the James Webb Space Telescope approaches scientific operation, there is much interest in exploring the redshift range beyond that accessible with Hubble Space Telescope imaging. Currently, the only means to gauge the presence of such early galaxies is to age-date the stellar population of systems in the reionisation era. As a significant fraction of $z\simeq7-8$ galaxies are inferred from Spitzer photometry to have extremely intense [OIII] emission lines, it is commonly believed these are genuinely young systems that formed at redshifts $z<10$, consistent with a claimed rapid rise in the star formation density at that time. Here we study a spectroscopically-confirmed sample of extreme [OIII] emitters at $z=1.3-3.7$, using both dynamical masses estimated from [OIII] line widths and rest-frame UV to near-infrared photometry to illustrate the dangers of assuming such systems are genuinely young. For the most extreme of our intermediate redshift line emitters, we find dynamical masses $10-100$ times that associated with a young stellar population mass, which are difficult to explain solely by the presence of additional dark matter or gaseous reservoirs. Adopting nonparametric star formation histories, we show how the near-infrared photometry of a subset of our sample reveals an underlying old ($>100$ Myr) population whose stellar mass is $\simeq40$ times that associated with the starburst responsible for the extreme line emission. Without adequate rest-frame near-infrared photometry we argue it may be premature to conclude that extreme line emitters in the reionisation era are low mass systems that formed at redshifts below $z\simeq10$.

Forming planetesimals from pebbles is a major challenge in our current understanding of planet formation. In a protoplanetary disk, pebbles drift inward near the disk midplane via gas drag and may enter a dead zone. In this context, we identified that the back-reaction of the drag of pebbles onto the gas could lead to a runaway pile-up of pebbles, the so-called "no-drift" mechanism. We improve upon the previous study of the no-drift mechanism by investigating the nature and characteristics of the resultant planetesimal belt. We perform 1D diffusion-advection simulations of drifting pebbles in the outer region of a dead zone by including back-reaction to the radial drift of pebbles and including planetesimal formation via streaming instability. We independently consider the parameters that regulate gas accretion and vertical stirring of pebbles in the disk midplane. In this study, the pebble-to-gas mass flux ($F_{\rm p/g}$) is fixed as a parameter. We find that planetesimals form initially within a narrow ring whose width expands as accumulating pebbles radially diffuse over time. The system finally reaches a steady state where the width of the planetesimal belt no longer changes. A non-negligible total mass of planetesimals (more than one Earth mass) is formed for a disk having $F_{\rm p/g} \gtrsim 0.1$ for more than $\sim 10-100$ kyr with nominal parameters: a gas mass flux of $\simeq 10^{-8} {\rm M}_\oplus$/yr, $\tau_{\rm s} \simeq 0.01-0.1$, $\alpha_{\rm mid} \lesssim 10^{-4}$, $\alpha_{\rm acc} \simeq 10^{-3}-10^{-2}$ at $r<10$ au, where $r$, $\tau_{\rm s}$, $\alpha_{\rm mid}$, and $\alpha_{\rm acc}$ are the heliocentric distance, the Stokes number, and the parameters in a dead zone controlling the efficiencies of vertical turbulent diffusion of pebbles (i.e., scale height of pebbles) and gas accretion of the $\alpha$-disk (i.e., gas surface density), respectively.

We analyze the simulation result shown in Hotta & Kusano, 2021 in which the solar-like differential rotation is reproduced. The Sun is rotating differentially with the fast equator and the slow pole. It is widely thought that the thermal convection maintains the differential rotation, but recent high-resolution simulations tend to fail to reproduce the fast equator. This fact is an aspect of one of the biggest problems in solar physics called the convective conundrum. Hotta & Kusano, 2021 succeed in reproducing the solar-like differential rotation without using any manipulation with unprecedentedly high-resolution simulation. In this study, we analyze the simulation data to understand the maintenance mechanism of the fast equator. Our analyses lead to conclusions that are summarized as follows. 1. Superequipatition magnetic field is generated by the compression, which can indirectly convert the massive internal energy to magnetic energy. 2. Extended subadiabatic region around the base of the convection zone and the efficient small-scale energy transport suppresses large-scale convection energy. 3. Non-Taylor--Proudman differential rotation is maintained by the entropy gradient caused by the anisotropic latitudinal energy transport enhanced by the magnetic field. 4. The fast equator is maintained by the meridional flow mainly caused by the Maxwell stress. The Maxwell stress itself also has a role in the angular momentum transport for fast near-surface equator (we call it the Punching ball effect). This study newly finds the role of the magnetic field in the maintenance of differential rotation

The $Gaia$ mission has provided an unprecedented wealth of information about the white dwarf population of our Galaxy. In particular, our studies show that the sample up to 100\,pc from the Sun can be considered as practically complete. This fact allows us to estimate a precise fraction of double-degenerate ($1.18\pm 0.10$\%) and white dwarf plus main-sequence stars ($6.31\pm0.23$\%) among all white dwarfs through comoving pairs identification. With the aid of a detailed population synthesis code we are able to reproduce synthetic white dwarf populations with nearly identical fractions as the observed ones, thus obtaining valuable information about the binary fraction, $f_{\rm b}$, initial mass ratio distribution, $n(q)$, and initial separation distribution, $f(a)$, among other parameters. Our best-fit model is achieved within a $1\sigma$ confidence level for $f(a)\propto a^{-1}$, $n(q)\propto q^{n_q}$, with $n_q=-1.13^{+0.12}_{-0.10}$ and $f_{\rm b}=0.32\pm 0.02$. The fraction of white dwarf mergers generated by this model is $9\sim16\%$, depending on the common-envelope treatment. As sub-products of our modelling we find that around $1\sim3\%$ of the white dwarf population are unresolved double-degenerates and that only $\sim1\%$ of all white dwarfs contain a He-core. Finally, only a mild kick during white dwarf formation seems to be necessary for fitting the observed sky separation of double-degenerate systems.

Cosmic Reionization imprints its signature on the temperature and polarization anisotropies of the cosmic microwave background (CMB). Advances in CMB telescopes have already placed a significant constraint on the history of reionization. As near-future CMB telescopes target the maximum sensitivity, or observations limited only by the cosmic variance (CV), we hereby forecast the potential of future CMB observations in constraining the history of reionization. In this study, we perform Markov Chain Monte Carlo analysis for CV-limited E-mode polarization observations such as the LiteBIRD (Light satellite for the studies of B-mode polarization and Inflation from cosmic background Radiation Detection), based on a few different methods that vary in the way of sampling reionization histories. We focus especially on estimating the very early history of reionization that occurs at redshifts $z>15$, which is quantified by the partial CMB optical depth due to free electrons at $z>15$, $\tau_{z>15}$. We find that reionization with $\tau_{z>15} \sim 0.008$, which are well below the current upper limit $\tau_{z>15} \sim 0.02$, are achievable by reionization models with minihalo domination in the early phase and can be distinguished from those with $\tau_{z>15} \lesssim 5\times 10^{-4}$ through CV-limited CMB polarization observations. An accurate estimation of $\tau_{z>15}$, however, remains somewhat elusive. We investigate whether resampling the E-mode polarization data with limited spherical-harmonic modes may resolve this shortcoming.

We present a large-scale simultaneous survey of the CO isotopologues ($\rm {}^{12}{CO}$, $\rm{}^{13}{CO}$, and $\rm{C}{}^{18}{O}$) J = 1 ${-}$ 0 line emission toward the Galactic plane region of l = 106.65$^\circ$ to 109.50$^\circ$ and b = ${-}$1.85$^\circ$ to 0.95$^\circ$ using the Purple Mountain Observatory 13.7 m millimeter-wavelength telescope. Except for the molecular gas in the solar neighborhood, the emission from the molecular gas in this region is concentrated in the velocity range of [${-}$60, ${-}$35] $\rm km~s^{-1}$. The gas in the region can be divided into four clouds, with mass in the range of $\sim$10$^{3}$ to 10$^{4}$\,${M_{\sun}}$. We have identified 25 filaments based on the $\rm {}^{13}{CO}$ data. The median excitation temperature, length, line mass, line width, and virial parameter of the filaments are 10.89 K, 8.49 pc, 146.11 ${M}_{\odot}~ \rm pc^{-1}$, 1.01 $\rm km~s^{-1}$, and 3.14, respectively. Among these filaments, eight have virial parameters of less than 2, suggesting that they are gravitationally bound and can lead to star formation. Nineteen {H \small {II}} regions or candidates have previously been found in the region and we investigate the relationships between these {H \small {II}} regions/candidates and surrounding molecular clouds in detail. Using morphology similarity and radial velocity consistency between {H \small {II}} regions/candidates and molecular clouds as evidence for association, and raised temperature and velocity broadening as signatures of interaction, we propose that 12 {H \small {II}} regions/candidates are associated with their surrounding molecular clouds. In the case of the {H \small {II}} region of S142, the energy of the {H \small {II}} region is sufficient to maintain the turbulence in the surrounding molecular gas.

Type Ia supernovae (SNe) are believed to be caused by the thermonuclear explosion of a white dwarf (WD), but the nature of the progenitor system(s) is still unclear. Recent theoretical and observational developments have led to renewed interest in double degenerate models, in particular the "helium-ignited violent merger" or "dynamically-driven double-degenerate double-detonation" (D$^6$). In this paper we take the output of an existing D$^6$ SN model and carry it into the supernova remnant (SNR) phase up to 4000 years after the explosion, past the time when all the ejecta have been shocked. Assuming a uniform ambient medium, we reveal specific signatures of the explosion mechanism and spatial variations intrinsic to the ejecta. The first detonation produces an ejecta tail visible at early times, while the second detonation leaves a central density peak in the ejecta that is visible at late times. The SNR shell is off-centre at all times, because of an initial velocity shift due to binary motion. The companion WD produces a large conical shadow in the ejecta, visible in projection as a dark patch surrounded by a bright ring. This is a clear and long-lasting feature that is localized, and its impact on the observed morphology is dependent on the viewing angle of the SNR. These results offer a new way to diagnose the explosion mechanism and progenitor system using observations of a Type Ia SNR.

We used New Horizons LORRI images to measure the optical-band ($0.4\lesssim\lambda\lesssim0.9{\rm\mu m}$) sky brightness within a high galactic-latitude field selected to have reduced diffuse scattered light from the Milky Way galaxy (DGL), as inferred from the IRIS all-sky $100~\mu$m map. We also selected the field to significantly reduce the scattered light from bright stars (SSL) outside the LORRI field. Suppression of DGL and SSL reduced the large uncertainties in the background flux levels present in our earlier New Horizons COB results. The raw total sky level, measured when New Horizons was 51.3 AU from the Sun, is $24.22\pm0.80{\rm ~nW ~m^{-2} ~sr^{-1}}.$ Isolating the COB contribution to the raw total required subtracting scattered light from bright stars and galaxies, faint stars below the photometric detection-limit within the field, and the hydrogen plus ionized-helium two-photon continua. This yielded a highly significant detection of the COB at ${\rm 16.37\pm 1.47 ~nW ~m^{-2} ~sr^{-1}}$ at the LORRI pivot wavelength of 0.608 $\mu$m. This result is in strong tension with the hypothesis that the COB only comprises the integrated light of external galaxies (IGL) presently known from deep HST counts. Subtraction of the estimated IGL flux from the total COB level leaves a flux component of unknown origin at ${\rm 8.06\pm1.92 ~nW ~m^{-2} ~sr^{-1}}.$ Its amplitude is equal to the IGL.

Here we report large-amplitude transit timing variations (TTVs) for AU\,Microcopii b and c as detected in combined TESS (2018, 2020) and CHEOPS (2020, 2021) transit observations. AU Mic is a young planetary system with a debris disk and two transiting warm Neptunes. A TTV on the order of several minutes was previously reported for AU Mic b, which was suggested to be an outcome of mutual perturbations between the planets in the system. In 2021, we observed AU Mic b (five transits) and c (three transits) with the CHEOPS space telescope to follow-up the TTV of AU Mic b and possibly detect a TTV for AU Mic c. When analyzing TESS and CHEOPS 2020--2021 measurements together, we find that a prominent TTV emerges with a full span of ~23 minutes between the two TTV extrema. Assuming that the period change results from a periodic process - such as mutual perturbations - we demonstrate that the times of transits in the summer of 2022 are expected to be 30--85 minutes later than predicted by the available linear ephemeris.

A rare population of massive disk galaxies have been found to invade the red sequence dominated by early-type galaxies. These red/quenched massive disk galaxies have recently gained great interest into their formation and origins. The usually proposed quenching mechanisms, such as bar quenching and environment quenching, seem not suitable for those bulge-less quenched disks in low-density environment. In this paper, we use the IllustrisTNG-300 simulation to investigate the formation of massive quenched central disk galaxies. It is found that these galaxies contain less gas and harbor giant supermassive black holes(SMBHs) (above $ 10^{8}M_{\odot}$) than their star forming counterparts. By tracing their formation history, we found that quenched disk galaxies formed early and preserved disk morphology for cosmological time scales. They have experienced less than one major merger on average and it is mainly mini-mergers (mass ratio $<$1/10) that contribute to the growth of their SMBHs. In the Illustris-TNG simulation the black hole feedback mode switches from thermal to kinetic feedback when the black hole mass is more massive than $\sim 10^{8}M_{\odot}$, which is more efficient to eject gas outside of the galaxy and to suppress further cooling of hot gaseous halo. We conclude that kinetic AGN feedback in massive red/quenched disk galaxy is the dominant quenching mechanism.

It is currently uncertain as to whether methane exists on Mars. Data from the Curiosity Rover suggests a background methane concentration of a few tenths parts per billion whereas data from the Trace Gas Orbiter suggest an upper limit of twenty parts per trillion. If methane exists on Mars then we do not understand fully the physical and chemical processes affecting its lifetime. Atmospheric models suggest an over-estimate in the lifetime by a factor of around six hundred compared with earlier observations. In the present work we assume the Curiosity Rover background methane value and estimate the uncertainty in atmospheric chemistry and mixing processes in our atmospheric column model 1D TERRA. Results suggest that these processes can only explain a factor of ~sixteen lowering in the methane lifetime. This implies that if methane is present then additional, currently unknown processes are required to explain the observed lifetime.

Magnetohydrodynamic star-in-a-box simulations of convection and dynamos in a solar-like star with different rotation rates are presented. These simulations produce solar-like differential rotation with a fast equator and slow poles, and magnetic activity that resembles that of the Sun with equatorward migrating activity at the surface. Furthermore, the ratio of rotation to cycle period is almost constant as the rotation period decreases in the limited sample considered here. This is reminiscent of the suggested inactive branch of stars from observations and differs from most earlier simulation results from spherical shell models. While the exact excitation mechanism of the dynamos in the current simulations is not yet clear, it is plausible that the greater freedom that the magnetic field has due to the inclusion of the radiative core and regions exterior to the star are important in shaping the dynamo.

Aims. We investigate the role of the accumulation of both magnetic helicity and magnetic energy in the generation of coronal mass ejections (CMEs) from emerging solar active regions (ARs). Methods. Using vector magnetic field data obtained by the Helioseismic and Magnetic Imager on board the Solar Dynamics Observatory, we calculate the magnetic helicity and magnetic energy injection rates as well as the resulting accumulated budgets in 52 emerging ARs from the start time of magnetic flux emergence until they reach heliographic longitude of 45\degr\ West (W45). Results. Seven of the ARs produced CMEs while 45 did not. In a statistical sense, the eruptive ARs accumulate larger budgets of both magnetic helicity and energy than the noneruptive ones over intervals that start from flux emergence start time and end (i) at the end of flux emergence phase, and (ii) when the AR produces its first CME or crosses W45, whichever happens first. We found magnetic helicity and energy thresholds of $9 \times 10^{41}$ Mx$^2$ and $2 \times 10^{32}$ erg, respectively, which, if crossed, ARs are likely to erupt. The segregation, in terms of accumulated magnetic helicity and energy budgets, of the eruptive ARs from the noneruptive ones is violated in one case when an AR erupts early in its emergence phase and in six cases with noneruptive ARs exhibiting large magnetic helicity and energy budgets. Decay index calculations may indicate that these ARs did not erupt because the overlying magnetic field provided stronger or more extended confinement than in eruptive ARs. Conclusions. Our results indicate that emerging ARs tend to produce CMEs when they accumulate significant budgets of both magnetic helicity and energy. Any study of their eruptive potential should place magnetic helicity on equal footing with magnetic energy.

We show that the blazar PKS 1424+240, which has been recently associated by IceCube with a neutrino excess at the $3.3\,\sigma$ level together with three other sources, is similar to the first plausible non-stellar neutrino source, TXS 0506+056, in being also a masquerading BL Lac object, i.e., intrinsically a flat-spectrum radio quasar with hidden broad lines and a standard accretion disk. We point out that these two sources share other properties, including spectral energy distribution, high powers, parsec scale properties, and possibly radio morphology. We speculate that the relatively rare combination of proton-loaded jets, possibly typical of high-excitation sources, and efficient particle acceleration processes, related to their relatively high synchrotron peak frequencies, might favour neutrino production in these two sources. GB6 J1542+6129, which has also recently appeared twice in a list of IceCube associations, seems also to belong to this rare blazar sub-class, which includes at most ~ 20 Fermi-4LAC blazars.

We search for gamma-ray emission from 114 Galactic high mass X-ray binaries, including 4 well studied catalogued sources, in 12.5 years of Fermi-LAT data in conjunction with the 10-year point source catalogue. Where a gamma-ray excess appears to be spatially coincident with an X-ray binary, further investigation is performed to ascertain whether this excess is the product of physical processes within the binary system itself. We identify gamma-ray excesses coincident with 20 high mass X-ray binaries where there is little or no prior evidence for gamma-ray emission. However, we find that many of these are false positives caused by source confusion or the gamma-ray background. Nonetheless, tentative but promising indicators of gamma-ray emission are identified for several new systems, notably including 1A 0535+262, RX J2030.5+4751 and SAX J1324.4-6200.

Here we present the analysis of the distribution of rotation periods and light curve amplitudes based on 2859 family asteroids in 16 Main Belt families based on 9912 TESS asteroid light curves in the TSSYS-DR1 asteroid light curve database. We found that the distribution of the light curve properties follow a family-specific character in some asteroid families, including the Hungaria, Maria, Juno, Eos, Eucharis, and Alauda families. While in other large families, these distributions are in general very similar to each other. We confirm that older families tend to contain a larger fraction of more spheroidal, low-amplitude asteroids. We found that rotation period distributions are different in the cores and outskirts of the Flora and Maria families, while the Vesta, Eos, and Eunomia families lack this feature. We also confirm that very fast spinning asteroids are close to spherical (or spinning top shapes), and minor planets rotating slower than ~11 hour are also more spherical than asteroids in the 4--8 hour period range and this group is expected to contain the most elongated bodies.

Context: We investigate the evolution of the sheath and leading edge (LE) structure of interplanetary coronal mass ejections (ICMEs) as function of distance in the inner heliosphere. Results are related both to the magnetic ejecta (ME) and to the ambient solar wind (SW). Aims: From a sample of 40 well-observed Helios 1/2 events, we derive the average density separately for sheath, LE, and ME. The results are placed into comparison with the upstream SW to investigate at which distance the sheath is formed. Methods: We use plasma and magnetic field measurements from Helios 1/2 data in the distance range 0.3-1 au from the ICME list by Bothmer and Schwenn (1998). For comparison, we add a sample of four ICMEs observed with PSP in 2019-2021 covering 0.32-0.62 au. Results. At the distance of ~13 Rs, the CME sheath becomes denser than the ambient SW density. At ~38 Rs the sheath structure density starts to dominate over the density within the ME. The ME density falls below the ambient SW density at ~230 Rs. Besides the well-known expansion of the ME, the sheath size shows a weak positive correlation with distance, while the LE does not expand. We find a moderate anti-correlation between sheath density and local SW plasma speed upstream of the ICME shock. An empirical relation is derived connecting the ambient SW speed with sheath and LE density. Conclusions: The average starting distance for actual sheath formation is found to be located at ~13 Rs. The ME expansion changes strongly at ~38 Rs, leading to a density dominance of the sheath structure. The LE can be understood as a structure isolated from the ambient SW flow. The results allow for better interpretation of ICME evolution and possibly mass increase due to sheath enlargement. The empirical results between sheath and LE density and ambient SW speed can be used for more detailed modeling of ICME evolution in the inner heliosphere.

The dynamics of magnetic flux tubes (MFTs) in the accretion disk of typical Herbig Ae/Be star with fossil large-scale magnetic field is modeled taking into account the buoyant and drag forces, radiative heat exchange with the surrounding gas, and the magnetic field of the disk. The structure of the disk is simulated using our magnetohydrodynamic (MHD) model, taking into account the heating of the surface layers of the disk with the stellar radiation. The simulations show that MFTs periodically rise from the innermost region of the disk with speeds up to $10-12$ km s$^{-1}$. MFTs experience decaying magnetic oscillations under the action of the external magnetic field near the disk's surface. The oscillation period increases with distance from the star and initial plasma beta of the MFT, ranging from several hours at $r=0.012$ au up to several months at $r=1$ au. The oscillations are characterized by pulsations of the MFT's characteristics including its temperature. We argue that the oscillations can produce observed IR-variability of Herbig Ae/Be stars, which would be more intense than in the case of T Tauri stars, since the disks of Herbig Ae/Be stars are hotter, denser and have stronger magnetic field.

We present a method for applying spatially resolved adiabatic and radiative loss processes to synthetic radio emission from hydrodynamic simulations of radio sources from active galactic nuclei (AGN). Lagrangian tracer particles, each representing an ensemble of electrons, are injected into simulations and the position, grid pressure, and time since the last strong shock are recorded. These quantities are used to track the losses of the electron packet through the radio source in a manner similar to the Radio AGN in Semi-analytic Environments (RAiSE) formalism, which uses global source properties to calculate the emissivity of each particle ex-situ. Freedom in the choice of observing parameters, including redshift, is provided through the post-processing nature of this approach. We apply this framework to simulations of jets in different environments, including asymmetric ones. We find a strong dependence of radio source properties on frequency and redshift, in good agreement with observations and previous modelling work. There is a strong evolution of radio spectra with redshift due to the more prominent inverse-Compton losses at high redshift. Radio sources in denser environments have flatter spectral indices, suggesting that spectral index asymmetry may be a useful environment tracer. We simulate intermediate Mach number jets that disrupt before reaching the tip of the lobe, and find that these retain an edge-brightened Fanaroff-Riley Type II morphology, with the most prominent emission remaining near the tip of the lobes for all environments and redshifts we study.

To probe this question, we perform a statistical analysis using the first Canadian Hydrogen Intensity Mapping Experiment Fast Radio Burst (CHIME/FRB) catalog and identify a few discriminant properties between repeating and non-repeating FRBs such as the repetition rate, duration, bandwidth, spectral index, peak luminosity, and potential peak frequency. If repeating and non-repeating FRBs belong to one population, their distribution distinctions for the repetition rate and duration can be explained by the selection effect due to the beamed emission as in Connor et al. (2020). However, we obtain that the distribution distinctions for the spectral index and potentially the peak frequency cannot be explained by the beamed emission within the framework of either the coherent curvature radiation or synchrotron maser emission. This indicates that there could be two populations. We further discuss three possible scenarios for the required two populations.

Aims. We aim to increase the contrast limits to detect new satellites orbiting known asteroids. We use cutting-edge data reduction techniques and data processing algorithms that are essential to best analyse the raw data provided by the instruments and increase their performances. Doing so, the unequalled performances of SPHERE also make it a unique tool to resolve and study asteroids in the solar system, expanding the domain of its main science targets. Methods. We applied a newly developed data reduction pipeline for integral field spectrographs on archival SPHERE data of a resolved asteroid, (130) Elektra. It was coupled with a dedicated point spread function reconstruction algorithm to model the asteroid halo. Following the halo removal, the moon signal could be extracted more accurately. The moon positions were fitted at three epochs and were used to derive the orbital parameters via a genetic-based algorithm. Results. We announce the discovery of S/2014 (130) 2, a third moon orbiting (130) Elektra, making it the first quadruple asteroid ever found. It is identified in three different epochs, 9, 30, and 31 Dec. 2014, at a respective angular separation of 258 mas (333 km), 229 mas (327 km), and 319 mas (457 km). We estimate that this moon has a period of 0.679 day and a semi-major axis of 344 km, with an eccentricity of 0.33 and an inclination of 38 degrees compared to the primary rotation axis. With a relative magnitude to the primary of 10.5, its size is estimated to be 1.6 km.

We discuss the relationship between dark matter and the entropy of the universe with the premise that dark matter exists in the form of primordial black holes (PBHs) in a hierarchy of mass tiers. The lightest tier are intermediate-mass PIMBHs within galaxies including the Milky Way. Supermassive black holes at galactic centres are in the second tier. We are led to speculate that there exists a third tier of extremely massive PBHs, more massive than entire galaxies. We discuss future observations by the Rubin Observatory and James Webb Space Telescope.

Working in pressureless magnetohydrodynamics, we examine the consequences of some peculiar dispersive properties of linear fast sausage modes (FSMs) in one-dimensional cylindrical equilibria with a continuous radial density profile ($\rho_0(r)$). As recognized recently on solid mathematical grounds, cutoff axial wavenumbers may be absent for FSMs when $\rho_0(r)$ varies sufficiently slowly outside the nominal cylinder. Trapped modes may therefore exist for arbitrary axial wavenumbers and density contrasts, their axial phase speeds in the long-wavelength regime differing little from the external Alfv$\acute{\rm e}$n speed. If these trapped modes indeed show up in the solutions to the associated initial value problem (IVP), then FSMs have a much better chance to be observed than expected with classical theory, and can be invoked to account for a considerably broader range of periodicities than practiced. However, with axial fundamentals in active region loops as an example, we show that this long-wavelength expectation is not seen in our finite-difference solutions to the IVP, the reason for which is then explored by superposing the necessary eigenmodes to re-solve the IVP. At least for the parameters we examine, the eigenfunctions of trapped modes are characterized by a spatial extent well exceeding the observationally reasonable range of the spatial extent of initial perturbations, meaning a negligible fraction of energy that a trapped mode can receive. We conclude that the absence of cutoff wavenumbers for FSMs in the examined equilibrium does not guarantee a distinct temporal behavior.

The 'First Stars' programme revealed the metal-poor halo star CS 31082-001 to be r-process and actinide rich, including the first measurement of a uranium abundance for an old star. To better characterise and understand such rare objects, we present the first abundance estimates of three elements (Be, V, Cu) for CS 31082-001 from analysis of its near-ultraviolet spectrum. Beryllium is rarely measured in giant stars, and we confirm that its abundance in this star is low due to the rather cool effective temperature that causes destruction of both Be and Li in its atmosphere. Vanadium and copper are iron-peak elements that are starting to be used as chemical-tagging indicators to investigate the origin of stellar populations. We find V and Cu abundances for CS 31082-001 that are comparable to other metal-poor stars, and present new chemical evolution models to investigate our results. In the case of V, extra nucleosynthesis due to interaction of neutrinos with matter is included in the models to be able to reproduce the measured abundance. Given the availability of high-quality spectroscopy of CS 31082-001, we also explore other atomic lines in the near-ultraviolet as a template for future studies of metal-poor stars with the planned CUBES instrument in development for the Very Large Telescope.

The recent analysis from the SH0ES Collaboration has confirmed the existence of a Hubble tension between measurements at high redshift ($z> 1000$) and at low redshift ($z<1$) at the $5\sigma$ level with the low redshift measurement giving a higher value. In this work we propose a particle physics model that can resolve the Hubble tension via an out of equilibrium hidden sector coupled to the visible sector. The particles that populate the dark sector consist of a dark fermion, which acts as dark matter, a dark photon, a massive scalar and a massless pseudo-scalar. Assuming no initial population of particles in the dark sector, feeble couplings between the visible and the hidden sectors via kinetic mixing populate the dark sector even though the number densities of hidden sector particles never reach their equilibrium distribution and the two sectors remain at different temperatures. A cosmologically consistent analysis is presented where a correlated evolution of the visible and the hidden sectors with coupled Boltzmann equations involving two temperatures, one for the visible sector and the other for the hidden sector, is carried out. The relic density of the dark matter constituted of dark fermions is computed in this two-temperature formalism. As a consequence, BBN predictions are upheld with a minimal contribution to $\Delta N_{\rm eff}$. However, the out-of-equilibrium decay of the massive scalar to the massless pseudo-scalar close to the recombination time causes an increase in $\Delta N_{\rm eff}$ to resolve the Hubble tension.

Extrasolar analogues of the Solar System's Kuiper belt offer unique constraints on outer planetary system architecture. Radial features such as the sharpness of disk edges and substructures such as gaps may be indicative of embedded planets within a disk. Vertically, the height of a disk can constrain the mass of embedded bodies. Edge-on debris disks offer a unique opportunity to simultaneously access the radial and vertical distribution of material, however recovering either distribution in an unbiased way is challenging. In this study, we present a non-parametric method to recover the surface brightness profile (face-on surface brightness as a function of radius) and height profile (scale height as a function of radius) of azimuthally symmetric, edge-on debris disks. The method is primarily designed for observations at thermal emission wavelengths, but is also applicable to scattered light observations under the assumption of isotropic scattering. By removing assumptions on underlying functional forms, this algorithm provides more realistic constraints on disk structures. We also apply this technique to ALMA observations of the AU Mic debris disk and derive a surface brightness profile consistent with estimates from parametric approaches, but with a more realistic range of possible models that is independent of parametrisation assumptions. Our results are consistent with a uniform scale height of 0.8 au, but a scale height that increases linearly with radius is also possible.

We present the first {\it XMM-Newton} observation of the classical supergiant high-mass X-ray binary XTE J1855$-$026 taken entirely during the eclipse of the neutron star (NS), covering the orbital phases $\phi= 0.00-0.11$. The analysis of the data allows us to a) compare with the parameters obtained during the existing pre eclipse observation and b) explore the back illuminated stellar wind of the B0I type donor. The black body component, used to describe the soft excess during pre eclipse, is not observed during eclipse. It must be then produced near the NS or along the donor-NS line. The $0.3-10$ keV luminosity during eclipse ($\sim 10^{34}$ erg s$^{-1}$) is 70 times lower than pre eclipse. The intensity of the Fe K$\alpha$ line, in the average eclipse spectrum, is $\sim 7.4$ times lower than the one measured during pre eclipse. Since K$\alpha$ photons can not be resonantly scattered in the wind, the vast majority of Fe K$\alpha$ emission must come from distances within $1R_{*}$ from the NS. The eclipse spectrum is successfully modelled through the addition of two photoionized plasmas, one with low ionization ($\log\xi_{\rm 1,cold}=0.36$) and high emission measure ($EM_{\rm 1,cold}\approx 3\times 10^{59}$ cm$^{-3}$) and another with high ionization ($\log\xi_{\rm 2,hot}=3.7$) and low emission measure ($EM_{\rm hot}\approx 2\times 10^{56}$ cm$^{-3}$). Assuming that the cold and hot gas phases are the clumps and the interclump medium of the stellar wind, respectively, and a clump volume filling factor of $\approx [0.04-0.05]$, typical for massive stars, a density contrast between clumps and the interclump medium of $n_{\rm c}/n_{\rm i}\approx 180$ is deduced, in agreement with theoretical expectations and optical-UV observations of massive star winds.

We present the discovery of the very energetic GRB 210905A at the high redshift z=6.312 and its luminous X-ray and optical afterglow. We obtained photometric and spectroscopic follow-up in the optical and near-infrared (NIR), covering both the prompt and afterglow emission from a few minutes up to 7.5 Ms after burst. With an isotropic gamma-ray energy of Eiso=1.27x10^54erg, GRB 210905A lies in the top ~7% GRBs in terms of energy released. Its afterglow is among the most luminous ever observed and, in particular, it is one of the most luminous in the optical at t<0.5 d, in the rest frame. The afterglow starts with a shallow evolution that can be explained by energy injection, and is followed by a steeper decay, while the spectral energy distribution is in agreement with slow cooling in a constant-density environment within the standard fireball theory. A jet break at 39+-21 d has been observed in the X-ray light curve; however, it is hidden in the H-band, potentially due to a constant contribution from an unknown component, most likely a foreground intervening galaxy and/or the host galaxy. We derived a half-opening angle of 7.9+-1.6 degrees, the highest ever measured for a z>~6 burst but within the range covered by closer events. The resulting collimation-corrected gamma-ray energy of 10^52erg is also among the highest ever measured. The moderately large half-opening angle argues against recent claims of an inverse dependence of the half-opening angle on the redshift. The total jet energy is likely too large for a standard magnetar, and suggests that the central engine of this burst was a newly formed black hole. Despite the outstanding energetics and luminosity of both GRB 210905A and its afterglow, we demonstrate that they are consistent within 2swith those of less distant bursts, indicating that the powering mechanisms and progenitors do not evolve significantly with redshift.

The tidal tails of Palomar 5 (Pal 5) have been the focus of many spectroscopic studies in an attempt to identify individual stars lying along the stream and characterise their kinematics. The well-studied trailing tail has been explored out to a distance of 15^\text{o} from the cluster centre, while less than four degrees have been examined along the leading tail. In this paper, we present results of a spectroscopic study of two fields along the leading tail that we have observed with the AAOmega spectrograph on the Anglo-Australian telescope. One of these fields lies roughly 7^\text{o} along the leading tail, beyond what has been previously been explored spectroscopically. Combining our measurements of kinematics and line strengths with Pan-STARRS1 photometric data and Gaia EDR3 astrometry, we adopt a probabilistic approach to identify 16 stars with high probability of belonging to the Pal 5 stream. Eight of these stars lie in the outermost field and their sky positions confirm the presence of ``fanning'' in the leading arm. We also revisit previously-published radial velocity studies and incorporate Gaia EDR3 astrometry to remove interloping field stars. With a final sample of 109 {\it bona fide} Pal 5 cluster and tidal stream stars, we characterise the 3D kinematics along the the full extent of the system. We provide this catalogue for future modeling work.

Aims. We aim to establish a rough first prospect on the potential of certain biorelevant solvents (water, ammonia and methane) to be present in liquid form inside the uppermost few meters of several modelled surfaces (rocky and icy crusts of various compositions) of hypothetical bodies orbiting active galactic nuclei (AGN), and investigate under which constraints this might occur. Methods. We adjust and average together X-ray spectra from a sample of 20 Type 1 Seyfert galaxies to calculate a mean snowline of the sample used. Based on this, we introduce variation of a hypothetical body's orbit across distances between 10% and 100% of the snowline radius, and calculate a sub-surface attenuation within four different model surface compositions for each. Surface compositions are based on lunar soil and solvent ices found in the milky way's circumnuclear region. We then use this as a continuous source term for a thermal model. Example bodies are systematically investigated with sizes between 1/30 and 20 earth radii. Further outlier variations are also considered (such as the case of bound rotation of the body) to end up with a perspective of solvent phases under a wide slew of many different conditions. Results. We find that liquid solvents are possible under a multitude of parameters, with temperature being the main constraint to liquid water and body size as well as pressure being the main constraint to liquid methane and ammonia. We further find that these results, when adjusted for snowline distance, depend less on the energy output of the central source within the Seyfert Type 1 AGN than on other parameters, such as body sizes and solvent properties.

The current properties of globular cluster systems (GCSs) are the result of the evolution experienced by their host galaxies, which shape the richness of the GCS as well as its spatial distribution, among other features. We carry out an analysis of the projected radial distribution of globular clusters for a sample of almost 30 early-type galaxies (ETGs) of intermediate and low luminosity, located in cluster environments (Virgo, Fornax and Coma). We also include in the study six ETGs, for which the parameters of their GCS radial profiles are publicly available. The final analysis is performed on an enlarged sample (~ 100 GCSs), by adding the GCSs of ETGs from our previous paper (Paper I). Scaling relations involving different parameters of the GCSs are obtained for the whole sample and complement those obtained in Paper I. Several of such relations point to a second-order dependence on the environmental density. Finally, the results are analysed in the literature context.

The last measurement of the diffuse emission spectrum of the Milky Way in the megaelectronvolt (MeV) photon energy range was performed by CGRO/COMPTEL more than 20 years ago. We report a new analysis with the spectrometer SPI aboard INTEGRAL in the band 0.5-8.0 MeV, finally superseding the signal-to-noise ratio of the historic observations. This is possible thanks to an elaborate instrumental background model and careful considerations of the selected data, which are strongly affected by solar activity. We base our analysis on energy-dependent spatial template fitting in a region of $\Delta l \times \Delta b = 95^\circ \times 95^\circ$ around the Galactic centre. Our flux estimates are consistent with COMPTEL measurements and show no `MeV bump'. The spectrum follows a power-law shape with index $-1.39 \pm 0.09_{\rm stat} \pm 0.10_{\rm syst}$ and an integrated flux of $(5.7 \pm 0.8_{\rm stat} \pm 1.7_{\rm syst}) \times 10^{-8}\,\mathrm{erg\,cm^{-2}\,s^{-1}}$ between 0.5 and 8.0 MeV. We find that cosmic-ray electrons and propagation models consistent with the latest Fermi/LAT, Voyager 1, and AMS-02 data are broadly in agreement with the inferred inverse Compton spectral shape. However, a mismatch of a factor of 2-3 in normalisation with respect to baseline expectations may point to enhanced target photon densities and/or electron source spectra in the inner Galaxy, slightly modified diffusion properties, or the presence of an unresolved population of MeV $\gamma$-ray sources.

Observations that require large physical instrument dimensions and/or a considerable amount of cryogens, as it is the case for high spatial resolution far infrared (FIR) astronomy, currently still face technological limits for their execution from space. Angular resolution and available observational capabilities are particularly affected. Balloon-based platforms promise to complement the existing observational capabilities by offering means to deploy comparatively large telescopes with comparatively little effort, including other advantages such as the possibility to regularly refill cryogens and to change and/or update instruments. The planned European Stratospheric Balloon Observatory (ESBO) aims at providing these additional large aperture FIR capabilities, exceeding the spatial resolution of Herschel, in the long term. The plans focus on reusable platforms performing regular flights and an operations concept that provides researchers with proposal-based access to observations. It thereby aims at offering a complement to other airborne, ground-based and space-based observatories in terms of access to wavelength regions, spatial resolution capability, and photometric stability. While the FIR capabilities are a main long-term objective, ESBO will offer benefits in other wavelength regimes along the way. Within the ESBO Design Study (ESBO DS), a prototype platform carrying a 0.5 m telescope for ultraviolet and visible light observations is being built and a platform concept for a next-generation FIR telescope is being studied. A flight of the UV/VIS prototype platform is estimated for 2021. In this paper we will outline the scientific and technical motivation for a large aperture balloon-based FIR observatory and the ESBO DS approach towards such an infrastructure. Secondly, we will present the technical motivation, science case, and instrumentation of the 0.5 m UV/VIS platform.

Parity-violating extensions of Maxwell electromagnetism induce a rotation of the linear polarization plane of photons during propagation. This effect, known as cosmic birefringence, impacts on the Cosmic Microwave Background (CMB) observations producing a mixing of $E$ and $B$ polarization modes which is otherwise null in the standard scenario. Such an effect is naturally parametrized by a rotation angle which can be written as the sum of an isotropic component $\alpha_0$ and an anisotropic one $\delta\alpha(\hat{\mathbf{n}})$. In this paper we compute angular power spectra and bispectra involving $\delta\alpha$ and the CMB temperature and polarization maps. In particular, contrarily to what happens for the cross-spectra, we show that even in absence of primordial cross-correlations between the anisotropic birefringence angle and the CMB maps, there exist non-vanishing three-point correlation functions carrying signatures of parity-breaking physics. Furthermore, we find that such angular bispectra still survive in a regime of purely anisotropic cosmic birefringence, which corresponds to the conservative case of having $\alpha_0=0$. These bispectra represent an additional observable aimed at studying cosmic birefringence and its parity-violating nature beyond power spectrum analyses. They provide also a way to perform consistency checks for specific models of cosmic birefringence. Moreover, we estimate that among all the possible birefringent bispectra, $\langle\delta\alpha\, TB\rangle$ and $\langle\delta\alpha\,EB\rangle$ are the ones which contain the largest signal-to-noise ratio. Once the cosmic birefringence signal is taken to be at the level of current constraints, we show that these bispectra are within reach of future CMB experiments, as LiteBIRD.

The development of Imaging Atmospheric Cherenkov Telescopes (IACTs) unveiled the sky in the teraelectronvolt regime, initiating the so-called "TeV revolution", at the beginning of the new millennium. This revolution was also facilitated by the implementation and adaptation of statistical tools for analyzing the shower images collected by these telescopes and inferring the properties of the astrophysical sources that produce such events. Image reconstruction techniques, background discrimination, and signal-detection analyses are just a few of the pioneering studies applied in recent decades in the analysis of IACTs data. This (succinct) review has the intent of summarizing the most common statistical tools that are used for analyzing data collected with IACTs, focusing on their application in the full analysis chain, including references to existing literature for a deeper examination.

We used the Rotation Measure (RM) catalogue derived from the LOFAR Two-metre Sky Survey Data Release 2 (LoTSS DR2) at 144-MHz to measure the evolution with redshift of the extragalactic RM (RRM: Residual RM) and the polarization fraction ($p$) of sources in low density environments. We also measured the same at 1.4-GHz by cross-matching with the NRAO VLA Sky Survey RM catalogue. We find that RRM versus redshift is flat at 144-MHz, but, once redshift-corrected, it shows evolution at high significance. Also $p$ evolves with redshift with a decrement by a factor of $\sim$8 at $z\sim2$. Comparing the 144-MHz and 1.4-GHz data, we find that the observed RRM and $p$ are most likely to have an origin local to the source at 1.4-GHz, while a cosmic web filament origin is favoured at 144-MHz. If we attribute the entire signal to filaments, we infer a mean rest frame RRM per filament of RRM_{0,f} = 0.71 \pm 0.07 rad m^{-2} and a magnetic field per filament of B_f = 32 \pm 3 nG. This is in agreement with estimates obtained with a complementary method based on synchrotron emission stacking, and with cosmological simulations if primordial magnetic fields are amplified by astrophysical source field seeding. The measurement of an RRM_{0,f} supports the presence of diffuse baryonic gas in filaments. We also estimated a conservative upper limit of the filament magnetic turbulence of \sigma_{ RRM_{0,f}} =0.039 \pm 0.001 rad m^{-2}, concluding that the ordered magnetic field component dominates in filaments.

In the paper we discuss the sonification of the simulated gravitational wave data for the future LISA space mission. First, we introduce the LISA project and its output. Then, we present Einstein's Sonata, a multimedia project devoted to the artistic public display of the LISA data. Einstein's Sonata features as its main element a music composition for prepared piano, Periplo del latte. The latter results from a sonification strategy mapping astronomical data onto music. We thus detail a four-stage sonification procedure, that features two data preprocessing stages, a mapping into an abstract control space and finally automatic notation generation.

A nebular spectrum of the peculiar, low-luminosity type Ia supernova 2010lp is modelled in order to estimate the composition of the inner ejecta and to illuminate the nature of this event. Despite having a normally declining light curve, SN 2010lp was similar spectroscopically to SN 1991bg at early times. However, it showed a very unusual double-peaked [OI] $\lambda\lambda\,6300,6363$ emission at late times (Taubenberger et al. 2013). Modelling of the nebular spectrum suggests that a very small amount of oxygen ($\sim0.05$ M$_{\odot}$), expanding at very low speed ($\sim2000$ km/s) is sufficient to reproduce the observed emission. The rest of the nebula is not too dissimilar from SN 1991bg, except that SN 2010lp is slightly more luminous. The double-peaked [OI] emission suggests that SN 2010lp may be consistent with the merger or collision of two low-mass white dwarfs. The low end of the SN Ia luminosity sequence is clearly populated by diverse events, where different channels may contribute.

We investigate the evolution of linear perturbations in the Symmetric Teleparallel Gravity, namely $f(Q)$ gravity, for which we design the $f(Q)$ function to match specific expansion histories. We consider different evolutions of the effective dark energy equation of state, $w_Q(a)$, which includes $w_Q=-1$, a constant $w_Q \neq -1$ and a fast varying equation of state. We identify clear patterns in the effective gravitational coupling, which accordingly modifies the linear growth of large scale structures. We provide theoretical predictions for the product of the growth rate $\tilde{f}$ and the root mean square of matter fluctuations $\sigma_8$, namely $\tilde{f}\sigma_8$ and for the sign of the cross-correlation power spectrum of the galaxy fluctuations and the cosmic microwave background radiation anisotropies. These properties can be used to distinguish the $f(Q)$ gravity from the standard cosmological model using accurate cosmological observations.

In the present paper, we aim to constrain the properties of the ionisation region in a star from the oscillation frequency variation (a so-called glitch) caused by rapid structural variations in this very region. In particular, we seek to avoid the use of calibration based on stellar models thus providing a truly independent estimate of these properties. These include both the helium abundance and other physical quantities that can have a significant impact on the oscillation frequencies such as the electronic degeneracy parameter or the extent of the ionisation region. Taking as a starting point our first paper, we applied structural perturbations of the ionisation zone to the wave equation for radial oscillations in an isentropic region. The resulting glitch model is thus able to exploit the information contained in the fast frequency oscillation caused by the helium ionisation but also in the slow trend accompanying that of hydrogen. This information can directly be expressed in terms of parameters related respectively to the helium abundance, electronic degeneracy and extent of the ionisation region. Using a Bayesian inference, we show that a substantial recovery of the properties at the origin of the glitch is possible. A degeneracy between the helium abundance and the electronic degeneracy is found to exist, which particularly affects the helium estimate. Extending the method to cases where the glitch is subject to contamination (e.g. surface effects), we noted the importance of the slow glitch trend associated with hydrogen ionisation. We propose using a Gaussian process to disentangle the frequency glitch from surface effects.

Neutron stars are a remarkable marriage of Einstein's theory of general relativity with nuclear physics. Their interiors harbor extreme matter that cannot be probed in the laboratory. At such high densities and pressures, their cores may consist predominantly of exotic matter such as free quarks or hyperons. Gravitational wave observations from the Laser Interferometer Gravitational-wave Observatory (LIGO) and from other interferometers, and X-ray observations from the Neutron Star Interior Composition Explorer (NICER), are beginning to pierce through the veil. These observations provide information about neutron star cores, and therefore, about the physics that makes such objects possible. In this review, we discuss what we have learned about the physics of neutron stars from gravitational wave and X-ray observations. We focus on what has been observed with certainty and what should be observable in the near future, with an eye out for the physics that these new observations will teach us.

The multicritical-point principle (MPP) provides a natural explanation of the large hierarchy between the Planck and electroweak scales. We consider a scenario in which MPP is applied to the Standard Model extended by two real singlet scalar fields $\phi$ and $S$, and a dimensional transmutation occurs by the vacuum expectation value of $\phi$. In this paper, we focus on the critical points that possess a $\mathbb Z_2$ symmetry $S\rightarrow -S$ and all the other fields are left invariant. Then $S$ becomes a natural dark matter (DM) candidate. Further, we concentrate on the critical points where $\phi$ does not possess further $\mathbb Z_2$ symmetry so that there is no cosmological domain-wall problem. Among such critical points, we focus on maximally critical one called CP-1234 that fix all the superrenormalizable parameters. We show that there remains a parameter region that satisfies the DM relic abundance, DM direct-detection bound and the current LHC constraints. In this region, we find a first-order phase transition in the early universe around the TeV-scale temperature. The resultant gravitational waves are predicted with a peak amplitude of ${\cal O}(10^{-12})$ at a frequency of $10^{-2}$-$10^{-1}$ Hz, which can be tested with future space-based instruments such as DECIGO and BBO.

In our previous work we investigated the effect of the hypothetical reflecting boundary near the black hole event horizon on the waveform from extreme mass-ratio inspirals (EMRIs). Even if the reflection efficiency is not extremely high, we found that a significant modification of the waveform can be expected. Then, the question is how to implement the search for this signature in the actual data analysis of future space gravitational wave antennas, such as LISA. In this paper we propose a simple but efficient method to detect the signature of the reflecting boundary. The interesting feature of the effect of the reflecting boundary on the orbital evolution of EMRIs is that the energy and angular momentum loss rates periodically oscillate in the frequency domain. The oscillation period is corresponding to the inverse time scale for the round trip of gravitational waves between the hypothetical boundary and the angular momentum barrier. We will show that this peculiar feature allows to detect the signature of the reflecting boundary without much additional computational cost.

We present a cosmological model arising from a gravitational theory with an infinite tower of higher-order curvature invariants that can reproduce the entire evolution of the Universe: from inflation to late-time acceleration, without invoking an inflaton nor a cosmological constant. The theory is Einsteinian-like. The field equations for a Friedmann-Lema\^{i}tre-Robertson-Walker metric are of second-order and can reproduce a late-time evolution that is consistent with the acceleration provided by the cosmological constant at low redshift. Our results force us to reinterpret the nature of dark energy, becoming a mechanism that is inherited solely from the geometry of spacetime.

The electron beam Weibel instability in the electrostatic collisionless shock is studied via particle in cell simulation. When the non-relativistic incoming plasmas collide with cold dilute plasmas, an electrostatic shock forms near the interface. Following that, a filamentary out-of-plane magnetic field is formed as a result of the Weibel instability. It is demonstrated that the anisotropy of incoming hot electrons is insufficient to trigger the Weibel instability. And the Weibel instability is excited by cold electrons in dilute plasmas. After being accelerated to relativistic velocities by the shock electric field into the dense plasmas, electrons in the dilute plasma have considerable anisotropy and can trigger the Weibel instability

Gravitational collapse is still poorly understood in the context of $f(R)$ theories of gravity, since the Oppenheimer-Snyder model is incompatible with their junction conditions. In this work, we will present a systematic approach to the problem. Starting with a thorough analysis of how the Oppenheimer-Snyder construction should be generalised to fit within metric $f(R)$ gravity, we shall subsequently proceed to explore the existence of novel exterior solutions compatible with physically viable interiors. Our formalism has allowed us to show that some paradigmatic vacuum metrics cannot represent spacetime outside a collapsing dust star in metric $f(R)$ gravity. Moreover, using the junction conditions, we have found a novel vacuole solution of a large class of $f(R)$ models, whose exterior spacetime is documented here for the first time in the literature as well. Finally, we also report the previously unnoticed fact that the Oppenheimer-Snyder model of gravitational collapse is incompatible with the Palatini formulation of $f(R)$ gravity.

The $U(1)_{B\textrm{--}L}$ symmetry, the essential component in the seesaw mechanism and leptogenesis, is naturally equipped with a massive gauge boson. When the gauge coupling is of the order of $\mathcal{O}(10^{-19})$, this gauge boson is a light and long-lived dark matter candidate which dominantly decays into active neutrinos. This consistent dark matter scenario predicts a characteristic neutrino signal that is potentially detectable at future neutrino observatories. Once detected, such a neutrino signal would serve as a smoking gun for this minimal extension to the Standard Model of particle physics, opening new windows to tackle cosmological and astrophysical conundra.

We derive a closed-form false vacuum decay rate at one loop in the thin wall limit, where the true and false vacua are nearly degenerate. We obtain the bounce configuration in $D$ dimensions, together with the Euclidean action with a higher order correction, counter-terms and renormalization group running. We extract the functional determinant via the Gel'fand-Yaglom theorem for low and generic orbital multipoles. The negative and zero eigenvalues appear for low multipoles and the translational zeroes are removed. We compute the fluctuations for generic multipoles, multiply and regulate the orbital modes. We find an explicit finite renormalized decay rate in $D = 3, 4$ and give a closed-form expression for the finite functional determinant in any dimension.

We report on the direct cosmic relic neutrino background search from the first two science runs of the KATRIN experiment in 2019. Beta-decay electrons from a high-purity molecular tritium gas source are analyzed by a high-resolution MAC-E filter around the kinematic endpoint at 18.57 keV. The analysis is sensitive to a local relic neutrino overdensity of 9.7e10 (1.1e11) at a 90% (95%) confidence level. A fit of the integrated electron spectrum over a narrow interval around the kinematic endpoint accounting for relic neutrino captures in the Tritium source reveals no significant overdensity. This work improves the results obtained by the previous kinematic neutrino mass experiments at Los Alamos and Troitsk. We furthermore update the projected final sensitivity of the KATRIN experiment to <1e10 at 90% confidence level, by relying on updated operational conditions.