Papers for Thursday, Apr 11 2024

We present the third data release of JADES, the JWST Advanced Deep Extragalactic Survey, providing both imaging and spectroscopy in the two GOODS fields. Spectroscopy consists of medium-depth and deep NIRSpec/MSA spectra of 4,000 targets, covering the spectral range 0.6-5.3 $\mu$m and observed with both the low-dispersion prism (R=30-300) and all three medium-resolution gratings (R=500-1,500). We describe the observations, data reduction, sample selection, and target allocation. We measured 2,375 redshifts (2,053 from multiple emission lines); our targets span the range from z=0.5 up to z=13, including 404 at z>5. The data release includes 2-d and 1-d fully reduced spectra, with slit-loss corrections and background subtraction optimized for point sources. We also provide redshifts and S/N>5 emission-line flux catalogs for the prism and grating spectra, and concise guidelines on how to use these data products. Alongside spectroscopy, we are also publishing fully calibrated NIRCam imaging, which enables studying the JADES sample with the combined power of imaging and spectroscopy. Together, these data provide the largest statistical sample to date to characterize the properties of galaxy populations in the first billion years after the Big Bang.

AGC 114905 is a dwarf gas-rich ultra-diffuse galaxy seemingly in tension with the cold dark matter (CDM) model. Specifically, the galaxy appears to have an extremely low-density halo and a high baryon fraction, while CDM predicts dwarfs to have very dense and dominant dark haloes. The alleged tension relies on the galaxy's rotation curve decomposition, which depends heavily on its inclination. This inclination, estimated from the gas morphology, remains somewhat uncertain. We present unmatched ultra-deep optical imaging of AGC 114905 reaching surface brightness limits $\mu_{\rm r,lim} \approx 32$ mag/arcsec$^2$ ($3\sigma$; 10 arcsec $\times$ 10 arcsec) obtained with the 10.4-m Gran Telescopio Canarias. With the new imaging, we characterise the galaxy's morphology, surface brightness, colours, and stellar mass profiles in great detail. The stellar disc has a similar extent as the gas, presents spiral arms-like features, and shows a well-defined edge. Stars and gas share similar morphology, and crucially, we find an inclination of $31\pm2^\circ$, in agreement with the previous determinations. We revisit the rotation curve decomposition of the galaxy, and we explore different mass models in the context of CDM, self-interacting dark matter (SIDM), fuzzy dark matter (FDM) or Modified Newtonian Dynamics (MOND). We find that the latter does not fit the circular speed of the galaxy, while CDM only does so with dark halo parameters rarely seen in cosmological simulations. Within the uncertainties, SIDM and FDM remain feasible candidates to explain the observed kinematics of AGC 114905.

If visible matter alone is present in the Universe, general relativity (GR) and its Newtonian weak field limit (WFL) cannot explain several pieces of evidence, from the largest to the smallest scales. The most investigated solution is the cosmological model $\Lambda$ cold dark matter ($\Lambda$CDM), where GR is valid and two dark components are introduced, dark energy (DE) and dark matter (DM), to explain the $\sim$70\% and $\sim$25\% of the mass-energy budget of the Universe, respectively. An alternative approach is provided by modified gravity theories, where a departure of the gravity law from $\Lambda$CDM is assumed, and no dark components are included. This work presents refracted gravity (RG), a modified theory of gravity formulated in a classical way where the presence of DM is mimicked by a gravitational permittivity $\epsilon(\rho)$ monotonically increasing with the local mass density $\rho$, which causes the field lines to be refracted in small density environments. Specifically, the flatter the system the stronger the refraction effect and thus, the larger the mass discrepancy if interpreted in Newtonian gravity. RG presented several encouraging results in modelling the dynamics of disk and elliptical galaxies and the temperature profiles of the hot X-ray emitting gas in galaxy clusters and a covariant extension of the theory seems to be promising.

The exact sources of high-energy neutrinos detected by the IceCube neutrino observatory still remain a mystery. For the first time, this work explores the hypothesis that galaxy mergers may serve as sources for these high-energy neutrinos. Galaxy mergers can host very high-energy hadronic and photohadronic processes, which may produce very high-energy neutrinos. We perform an unbinned maximum-likelihood-ratio analysis utilizing the galaxy merger data from six catalogs and 10 years of public IceCube muon-track data to quantify any correlation between these mergers and neutrino events. First, we perform the single source search analysis, which reveals that none of the considered galaxy mergers exhibit a statistically significant correlation with high-energy neutrino events detected by IceCube. Furthermore, we conduct a stacking analysis with three different weighting schemes to understand if these galaxy mergers can contribute significantly to the diffuse flux of high-energy astrophysical neutrinos detected by IceCube. We find that upper limits (at $95\%$ c.l.) of the all flavour high-energy neutrino flux, associated with galaxy mergers considered in this study, at $100$ TeV with spectral index $\Gamma=-2$ are $2.57\times 10^{-18}$, $8.51 \times 10^{-19}$ and $2.36 \times 10^{-18}$ $\rm GeV^{-1}\,cm^2\,s^{-1}\,sr^{-1}$ for the three weighting schemes. This work shows that these selected galaxy mergers do not contribute significantly to the IceCube detected high energy neutrino flux. We hope that in the near future with more data, the search for neutrinos from galaxy mergers can either discover their neutrino production or impose more stringent constraints on the production mechanism of high-energy neutrinos within galaxy mergers.

A large fraction of massive stars are found in higher order systems where the presence of a tertiary may significantly modify the system's evolution. In particular, it can lead to increased numbers of compact object binaries and accelerate their mergers with important implications for gravitational wave observations. Using Gaia, we constrain the number of Galactic supernovae that produce unbound triples. We do this by searching 8 supernova remnants for stars with consistent Gaia parallaxes and paths intersecting near the center of the supernova remnant at a time consistent with the age of the remnant. We find no candidates for unbound triple systems. Combined with prior work, less than 11.4\% of supernovae leave behind unbound triples at a 90\% confidence limit. The absence of such systems limits their role in the evolution of massive stars and the formation of merging compact objects.

We present a comprehensive spectro-photometric analysis of the galaxy GS9422 from the JADES GTO survey located at $z=5.943$, anomalously showing a simultaneous strong Ly$\alpha$ emission feature and damped Ly$\alpha$ absorption (DLA), based on JWST NIRSpec and NIRCam observations. The best-fit modelling of the spectral energy distribution (SED) reveals a young, low-mass (${\rm log}(M_\star/M_{\odot}) = 7.8 \pm 0.01$) galaxy, with a mass-weighted mean age of the stellar population of $(10.9^{+0.07}_{-0.12})\,$Myr. The identified strong nebular emission lines suggest a highly ionized ($O_{32} = 59$), low-metallicity ($12+\log({\rm O/H}) = 7.78\pm 0.10$) star-forming galaxy with a star-formation rate SFR = ($8.2 \pm 2.8$) $\rm M_{\odot}\;yr^{-1}$ over a compact surface area $A_e = 1.85$ kpc$^{2}$, typical for galaxies at this epoch. We carefully model the rest-frame UV NIRSpec Prism spectrum around the Ly$\alpha$ edge, finding that the Ly$\alpha$ emission-line redshift is consistent with the longer-wavelength recombination lines and an escape fraction of $f_{\rm esc,Ly\alpha} = 30\%$ but that the broad DLA feature is not able to converge on the same redshift. Instead, our modelling suggests $z_{\rm abs}= 5.40 \pm 0.10$, the exact redshift of a newly identified proto-cluster in nearby projection to the target galaxy. We argue that most of the HI gas producing the strong Ly$\alpha$ damping wing indeed has to be unassociated with the galaxy itself, and thus may indicate that we are probing the cold, dense circumcluster medium of this massive galaxy overdensity. These results provide an alternative solution to the recent claims of continuum nebular emission or an obscured active galactic nucleus dominating the rest-frame UV parts of the spectrum and provide further indications that strong DLAs might preferentially be associated with galaxy overdensities. [Abridged]

We present the first estimate of the HI mass function (HIMF) of star-forming galaxies at $z\approx1$, obtained by combining our measurement of the scaling relation between HI mass ($M_{HI}$) and B-band luminosity ($M_B$) of star-forming galaxies with literature estimates of the B-band luminosity function at $z\approx1$. We determined the $M_{HI}-M_B$ relation by using the GMRT-CATz1 survey of the DEEP2 fields to measure the average HI mass of blue galaxies at $z=0.74-1.45$ in three separate $M_B$ subsamples. This was done by separately stacking the HI 21 cm emission signals of the galaxies in each subsample to detect, at (3.5-4.4)$\sigma$ significance, the average HI 21 cm emission of each subsample. We find that the $M_{HI}-M_B$ relation at $z\approx1$ is consistent with that at $z\approx0$. We combine our estimate of the $M_{HI}-M_B$ relation at $z\approx1$ with the B-band luminosity function at $z\approx1$ to determine the HIMF at $z\approx1$. We find that the number density of galaxies with $M_{HI}>10^{10} M_\odot$ (higher than the knee of the local HIMF) at $z\approx1$ is a factor of $\approx4-5$ higher than that at $z\approx0$, for a wide range of assumed scatters in the $M_{HI}-M_B$ relation. We rule out the hypothesis that the number density of galaxies with $M_{HI}>10^{10} M_\odot$ remains unchanged between $z \approx 1$ and $z\approx0$ at $\gtrsim99.7$\% confidence. This is the first statistically significant evidence for evolution in the HIMF of galaxies from the epoch of cosmic noon.

A novel methodology for analysing the relation between the energy density in gravitational waves and primordial power spectra is developed. Focusing on scalar-induced gravitational radiation, this methodology is applied to a number of scenarios for the primordial black hole formation. Being differed from conventional Bayesian approaches, its advantages include directness and computational efficiency, which are crucial for handling the complex data characteristic of gravitational wave research. As an important application, it is demonstrated that it allows to systematically identify all scenarios consistent with current and future pulsar-timing-array data.

We present a new suite of late-end reionization simulations performed with ATON-HE, a revised version of the GPU-based radiative transfer code ATON that includes helium. The simulations are able to reproduce the Ly$\alpha$ flux distribution of the E-XQR-30 sample of QSO absorption spectra at $5 \lesssim z \lesssim 6.2$, and show that a large variety of reionization models are consistent with these data. We explore a range of variations in source models and in the early-stage evolution of reionization. Our fiducial reionization history has a midpoint of reionization at $z = 6.5$, but we also explore an `Early' reionization history with a midpoint at $z = 7.5$ and an `Extremely Early' reionization history with a midpoint at $z = 9.5$. Haloes massive enough to host observed Ly$\alpha$ emitters are highly biased. The fraction of such haloes embedded in ionized bubbles that are large enough to allow high Ly$\alpha$ transmission becomes close to unity much before the volume filling factor of ionized regions. For our fiducial reionization history this happens at $z = 8$, probably too late to be consistent with the detection by JWST of abundant Ly$\alpha$ emission out to $z = 11$. A reionization history in our `Early' model or perhaps even our `Extremely Early' model may be required, suggesting a Thomson scattering optical depth in tension with that reported by Planck, but consistent with recent suggestions of a significantly higher value.

We present high spectral resolution observations of the hot Jupiter WASP-94 A b using the HARPS instrument on ESO's 3.6m telescope in La Silla, Chile. We probed for Na absorption in its atmosphere as well as constrained the previously reported misaligned retrograde orbit using the Rossiter-McLaughlin effect. Additionally, we undertook a combined atmospheric retrieval analysis with previously published low-resolution data. We confirm the retrograde orbit as well as constrain the orbital misalignment with our measurement of a projected spin-orbit obliquity of $\lambda = 123.0 \pm 3.0 ^\circ$. We find a tentative detection of Na absorption in the atmosphere of WASP-94 A b, independent of the treatment of the Rossiter-McLaughlin effect in our analysis (3.6$\sigma$ and 4.4$\sigma$). We combine our HARPS high resolution data with low resolution data from the literature and find that while the posterior distribution of the Na abundance results in a tighter constraint than using a single data set, the detection significance does not improve (3.2$\sigma$), which we attribute to degeneracies between the low and high resolution data.

Nowadays, astronomers perform point spread function (PSF) fitting for most types of observational data. Interpolation of the PSF is often an intermediate step in such algorithms. In the case of the Multi-AO Imaging Camera for Deep Observations (MICADO) at the Extremely Large Telescope (ELT), PSF interpolation will play a crucial role in high-precision astrometry for stellar clusters and confirmation of the Intermediate-Mass Black Holes (IMBHs) presence. Significant PSF variations across the field of view invalidate the approach of deconvolution with a mean PSF or on-axis PSF. The ignoring of PSF variations can be especially unsatisfactory in the case of Single Conjugate Adaptive Optics (SCAO) observations, as these sophisticated and expensive systems are designed to achieve high resolution with ground-based telescopes by correcting for atmospheric turbulence in the direction of one reference star. In plenty of tasks, you face the question: How can I establish the quality of PSF fitting or interpolation? Our study aims to demonstrate the variety of PSF quality metrics, including the problem of revealing IMBHs in stellar clusters.

We present a stability analysis of a large set of simulated planetary systems of three or more planets based on architectures of multiplanet systems discovered by \textit{Kepler} and \textit{K2}. We propagated 21,400 simulated planetary systems up to 5 billion orbits of the innermost planet; approximately 13% of these simulations ended in a planet-planet collision within that timespan. We examined trends in dynamical stability based on dynamical spacings, orbital period ratios, and mass ratios of nearest-neighbor planets as well as the system-wide planet mass distribution and the spectral fraction describing the system's short-term evolution. We find that instability is more likely in planetary systems with adjacent planet pairs that have period ratios less than two and in systems of greater variance of planet masses. Systems with planet pairs at very small dynamical spacings (less than $\sim10-12$ mutual Hill radius) are also prone to instabilities, but instabilities also occur at much larger planetary separations. We find that a large spectral fraction (calculated from short integrations) is a reasonable predictor of longer-term dynamical instability; systems that have a large number of Fourier components in their eccentricity vectors are prone to secular chaos and subsequent eccentricity growth and instabilities.

JWST observations have recently begun delivering the first samples of Ly velocity profile measurements at z>6, opening a new window on the reionization process. Interpretation of z>6 line profiles is currently stunted by limitations in our knowledge of the intrinsic Lya profile (before encountering the IGM) of the galaxies that are common at z>6. To overcome this shortcoming, we have obtained resolved (R~3900) Lya spectroscopy of 42 galaxies at z=2.1-3.4 with similar properties as are seen at z>6. We quantify a variety of Lya profile statistics as a function of [OIII]+H$\beta$ EW. Our spectra reveal a new population of z~2-3 galaxies with large [OIII]+H$\beta$ EWs (>1200A) and a large fraction of Lya flux emerging near the systemic redshift (peak velocity ~0km/s). These spectra indicate that low density neutral hydrogen channels are able to form in a subset of low mass galaxies that experience a burst of star formation (sSFR >100/Gyr). Other extreme [OIII] emitters show weaker Lya that is shifted to higher velocities (~240km/s) with little emission near line center. We investigate the impact the IGM is likely to have on these intrinsic line profiles in the reionization era, finding that the centrally peaked Lya emitters should be strongly attenuated at z>5. We show that these line profiles are particularly sensitive to the impact of resonant scattering from infalling IGM and can be strongly attenuated even when the IGM is highly ionized at z~5. We compare these expectations against a database of z>6.5 galaxies with robust velocity profiles measured with JWST/NIRSpec in its grating mode. We find one z=8.28 source with strong Lya (EW=137A) and very small velocity offset (32km/s), likely implying a rare ionized sightline (>0.5pMpc) at z>8. But overall the results confirm the prediction of our simulations, revealing significantly larger peak velocities than are seen in our z~2-3 sample.

We present a general procedure for deriving a line profile model for massive star X-ray spectra that captures the dynamics of the wind more directly. The basis of the model is the analytic solution to the problem of variable jets in Herbig-Haro objects given by \citet{Canto2000}. In deriving our model, we generalize this jet solution to include flows with a prescribed nonzero acceleration for the context of radiatively driven winds. We provide example line profiles generated from our model for the case of sinusoidal velocity and mass ejection variations. The example profiles show the expected shape of massive star X-ray emission lines, as well as interesting but complicated trends with the model parameters. This establishes the possibility that observed X-rays could be a result of temporal variations seeded at the wind base, rather than purely generated intrinsically within the wind volume, and can be described via a quantitative language that connects with the physical attributes of those variations, consistently with the downstream momentum-conserving nature of radiatively cooled shocked radial flows.

Gas-phase metallicity gradients are a crucial element in understanding the chemical evolution of galaxies. We use the FOGGIE simulations to study the metallicity gradients ($\nabla Z$) of six Milky Way-like galaxies throughout their evolution. FOGGIE galaxies generally exhibit steep negative gradients for most of their history, with only a few short-lived instances reaching positive slopes that appear to arise mainly from interactions with other galaxies. FOGGIE concurs with other simulation results but disagrees with the robust observational finding that flat and positive gradients are common at $z>1$. By tracking the metallicity gradient at a rapid cadence of simulation outputs ($\sim 5$--10 Myr), we find that theoretical gradients are highly stochastic: the FOGGIE galaxies spend $\sim 30-50$\% of their time far away from a smoothed trajectory inferred from analytic models or other, less high-cadence simulations. This rapid variation makes instantaneous gradients from observations more difficult to interpret in terms of physical processes. Because of these geometric and stochastic complications, we explore non-parametric methods of quantifying the evolving metallicity distribution at $z > 1$. We investigate how efficiently non-parametric measures of the 2-D metallicity distribution respond to metal production and mixing. Our results suggest that new methods of quantifying and interpreting gas-phase metallicity will be needed to relate trends in upcoming high-$z$ {\it JWST} observations with the underlying physics of gas accretion, expulsion, and recycling in early galaxies.

Modern cosmology rests on the cosmological principle, that on large enough scales the Universe is both homogeneous and isotropic. A corollary is that galaxies' spin vectors should be isotropically distributed on the sky. This has been challenged by multiple authors for over a decade, with claims to have detected a statistically significant dipole pattern of spins. We collect all publicly available datasets with spin classifications (binary clockwise/anticlockwise), and analyse them for large-angle anisotropies ($\ell \le 2$). We perform each inference in both a Bayesian and frequentist fashion, the former establishing posterior probabilities on the multipole parameters and the latter calculating $p$-values for rejection of the null hypothesis of isotropy (i.e. no power at $\ell>0$). All analysis indicate consistency with isotropy to within $3\sigma$. We isolate the differences with contrary claims in the ad hoc or biased statistics that they employ.

Observations of cooler atmospheres of super-Earths and Neptune sized objects often show flat transmission spectra. The most likely cause of this trend is the presence of aerosols (i.e. clouds and hazes) in the atmospheres of such objects. High-resolution spectroscopy provides an opportunity to test this hypothesis by targeting molecular species whose spectral line cores extend above the level of such opaque decks. In this work, we analyse high-resolution infrared observations of the warm Neptune GJ 3470 b taken over two transits using CARMENES (R $\sim$ 80,000) and look for signatures of H$_2$O (previously detected using HST WFC3+Spitzer observations) in these transits with a custom pipeline fully accounting for the effects of data cleaning on any potential exoplanet signal. We find that our data are potentially able to weakly detect ($\sim3\sigma$) an injected signal equivalent to the best-fit model from previous HST WFC3+Spitzer observations. However, we do not make a significant detection using the actual observations. Using a Bayesian framework to simultaneously constrain the H$_2$O Volume Mixing Ratio (VMR) and the cloud top pressure level, we select a family of models compatible with the non detection. These are either very high VMR, cloud-free models, solar-abundance models with a high cloud deck, or sub-solar abundance models with a moderate cloud deck. This is a broader range compared to published results from low-resolution spectroscopy, but is also compatible with them at a 1$\sigma$ level.

We use 1.4-4.6 micron multi-band photometry of the small inner Uranian and Neptunian satellites obtained with the James Webb Space Telescope's near-infrared imager NIRCam to characterize their surface compositions. We find that the satellites of the ice giants have, to first-order, similar compositions to one another, with a 3.0 micron absorption feature possibly associated with an O-H stretch, indicative of water ice or hydrated minerals. Additionally, the spectrophotometry for the small ice giant satellites matches spectra of some Neptune Trojans and excited Kuiper belt objects, suggesting shared properties. Future spectroscopy of these small satellites is necessary to identify and better constrain their specific surface compositions.

We report accretion-powered pulsations for the first time during thermonuclear bursts in hard X-rays, which were observed with Insight-HXMT in 2022 during the outburst of the accreting X-ray millisecond pulsar MAXI J1816-195. By stacking 73 bursts, we detected pulse profiles in 8-30 keV and 30-100 keV during bursts, which are identical to those obtained from the persistent (non-burst) emission. On average, no significant phase lag was observed between burst and persistent pulse profiles. In addition, we suggest that the interaction with burst photons can be used as a direct diagnostic to distinguish contributions from the hot plasma near polar caps and the corona around the accretion disk, which are highly degenerate in their spectral shapes.

In this paper we investigate the stellar populations and star formation histories of 235 active galactic nuclei (AGN)-host dwarf galaxies, consisting of four samples identified separately with different methods (i.e., radio, X-ray, mid-IR and variability), utilizing the synthesis code STARLIGHT and spectra from the Sloan Digital Sky Survey (SDSS) Data Release 8. Our results show that the variability sample is the oldest, while the mid-IR sample is the youngest, for which the luminosity at 4020 \AA\ is dominated ($>50\%$) by the young population ($t<10^8$ yr). The light-weighted mean stellar age of the whole sample is in general about 0.7 dex younger than the optical sample studie in Cai et al. We compare the population results between fitting models with and without a power-law (PL) component and find that the neglect of a PL component would lead to an under- and over-estimation by 0.2 and 0.1 dex for the light- and mass-weighted mean stellar age, respectively, for our sample of dwarf galaxies, which has a mean fractional contribution of $\sim$16\% from the AGN. In addition, we obtain further evidence for a possible suppression of star formation in the host galaxy by the central AGN. We also find that there exists an anti-correlation between the extinction-corrected [O\,{\sc iii}] luminosity and light-weighted mean stellar age, confirming our previous finding that there is a physical connection between AGN and star-forming activies in AGN-host dwarfs.

In this paper, we investigate the behavior of a massive scalar field dark matter scenarios in the large mass limit around a central Reissner-Nordstr\"{o}m black hole. This study is motivated by observations from the Event Horizon Telescope collaboration, which does not exclude the possibility of the existence of such black holes. Through these inquiries, we uncover that the electric charge may significantly impact the scalar field profile and the density profile in the vecinty of the black hole. For the maximum electric charge allowed by the constraints of the Event Horizon Telescope, the maximum accretion rate decreases by $\thicksim$ 50 \% compared to the Schwarszchild case for marginally bound orbits. The maximum accretion rate of the massive scalar field is approximately $\dot M_{\text{SFDM}} \thicksim 10^{-8} M_{\odot} \;\text{yr}^{-1}$, which is significantly lower than the typical baryonic accretion rate commonly found in the literature. This implies that the scalar cloud located at the center of galaxies may have survived untill present times.

We set up a formalism for calculating the energy density generated in a quantized massive scalar field in the course of the drastic change in spacetime geometry at the end of the inflationary era. The calculation relies on the notion of adiabatic vacuum. The Bogolubov coefficients are computed by employing the sudden approximation. After obtaining a general formula, we calculate explicitly the energy density generated in a particle species with $m/H \ll1$, where $m$ is the particle mass and $H$ is the Hubble constant during the inflationary epoch. We find the contribution of the long-wavelength modes to be $\propto H^5/m$. If such particles are very weakly interacting, they can come to dominate the total energy density in the Universe. Other cosmological implications are also discussed.

Solar Orbiter provides unique capabilities to understand the heliosphere. In particular, it has made observations of the far-side of the Sun and provides unique information to improve space weather monitoring. We aim to quantify how far-side data will affect simulations of the corona and the interplanetary medium, especially in the context of space weather forecasting. We focused on a time period with a single sunspot emerging on the far-side in February 2021. We used two different input magnetic maps: one with the far-side active region and one without. We used three different coronal models: a semi-empirical model (potential field source surface or PFSS) and two different magnetohydrodynamic models (Wind Predict and Wind Predict-AW). We compared all the models with both remote sensing and in situ observations. We find that the inclusion of the far-side active region in the various models has a small local impact due to the limited amount of flux of the sunspot (at most 8% of the total map flux), which leads to coronal hole changes of around 7% for all models. Interestingly, there is a more global impact on the magnetic structure seen in the current sheet, with clear changes in the coronal hole boundaries visible in extreme ultra-violet (EUV) on the western limb. For the Wind Predict-AW model, we demonstrate that the inclusion of the far-side data improves both the structure of the streamers and the connectivity to the spacecraft. In conclusion, the inclusion of a single far-side active region may have a small local effect with respect to the total magnetic flux, but it has global effects on the magnetic structure, and thus it must be taken into account to accurately describe the Sun-Earth connection. The flattening of the heliospheric current sheet for all models reveals an increase of the source surface height, which affects the open and closed magnetic field line distributions.

The DESI year one observations can help probe new physics on cosmological scales. In light of the latest DESI BAO measurements, we constrain four popular cosmological scenarios including inflation, modified gravity, annihilating dark matter and interacting dark energy. Using a data combination of BICEP/Keck array, cosmic microwave background and DESI, we obtain the $1\sigma$ and $2\sigma$ constraints on the tensor-to-scalar ratio $r_{0.05}= 0.0176^{+0.0070}_{-0.0130}$ and $r_{0.05}=0.018^{+0.020}_{-0.017}$. Using the combination of cosmic microwave background and DESI, we find a $2.4\sigma$ evidence for gravitational theories beyond the general relativity, shrinks the dark matter annihilation cross-section by $12\%$ relative to cosmic microwave background, and obtain a $1.6\sigma$ hint of the positive interaction between dark matter and dark energy indicating that energy may be transferred from dark matter to dark energy in the dark sector of the universe. Future DESI observations could go a step further to explore the nature of inflation, dark matter and dark energy, and test the validity of general relativity on cosmological scales.

We study the properties of double white dwarf (DWD) mergers by performing hydrodynamic simulations using the new and improved adaptive mesh refinement code Octo-Tiger. We follow the orbital evolution of DWD systems of mass ratio q=0.7 for tens of orbits until and after the merger to investigate them as a possible origin for R Coronae Borealis (RCB) type stars. We reproduce previous results, finding that during the merger, the Helium WD donor star is tidally disrupted within 20-80 minutes since the beginning of the simulation onto the accretor Carbon-Oxygen WD, creating a high temperature shell around the accretor. We investigate the possible Helium burning in this shell and the merged object's general structure. Specifically, we are interested in the amount of Oxygen-16 dredged-up to the hot shell and the amount of Oxygen-18 produced. This is critical as the discovery of very low Oxygen-16 to Oxygen-18 ratios in RCB stars pointed out the merger scenario as a favorable explanation for their origin. A small amount of hydrogen in the donor may help keep the Oxygen-16 to Oxygen-18 ratios within observational bounds, even if moderate dredge-up from the accretor occurs. In addition, we perform a resolution study to reconcile the difference found in the amount of Oxygen-16 dredge-up between smoothed-particle hydrodynamics and grid-based simulations.

The production mechanism of astrophysical high-energy neutrinos is not yet understood. A common assumption is that beamed relativistic outflows (jets) driven by accreting black holes are needed to accelerate particles to such high energies to produce high-energy neutrinos. Indeed, the first astrophysical high-energy neutrino source candidate identified by IceCube at a significance level of $>3\sigma$ was a blazar -- an AGN with an accreting supermassive black hole that drives a relativistic jet directed towards Earth. Recently, IceCube discovered strong evidence that Seyfert galaxies also emit neutrinos, which appears unrelated to jet activity. Here, we show that the neutrino--hard X-ray flux ratio of the blazar TXS 0506+056 is consistent with neutrino production in a $\gamma$-obscured region near the central supermassive black hole, with the X-ray flux corresponding to reprocessed $\gamma$-ray emission with flux comparable to that of neutrinos. Similar neutrino--hard X-ray flux ratios were found for three of IceCube's Seyfert galaxies, raising the possibility of a common neutrino production mechanism that may not involve a strong jet. We examine how future observations could test the jet origin of blazar neutrinos.

Charged particles, generated in solar flares, sometimes can get extremely high energy, above the 500 MeV level, and produce abrupt ground level enhancements (GLEs) on the ground-based detectors of cosmic rays. The initial flares are strong eruptions and they should be originated from active regions (ARs). A list of GLE events and associated flares was initially available, and our aim here was to find the hosting AR for each GLE event. Moreover, we aimed to classify the revealed ARs using the magneto-morphological classification (MMC: \citealp{2021MNRAS.507.3698A}). We have shown that in 94\% of cases such ARs belong to the most complex morphological classes, namely, $\beta \gamma$, $\beta \delta$, $\gamma \delta$, $\beta \gamma \delta$ classes by the Hale classification and B2, B3 classes by the MMC. We also found that the GLE-associated ARs are the ARs with the total unsigned magnetic flux much stronger than the common ARs of the same complexity. The set of GLE-related ARs only partially overlaps with the set of SARs (super-active regions). These ARs seem to be a manifestation of nonlinearities in the regular process of the global mean-field dynamo, the key ingredient to keep fluctuations and to create critical conditions in different aspects of the solar activity.

We present the first results of the JWST program PROJECT-J (PROtostellar JEts Cradle Tested with JWST ), designed to study the Class I source HH46 IRS and its outflow through NIRSpec and MIRI spectroscopy (1.66 to 28 micron). The data provide line-images (~ 6.6" in length with NIRSpec, and up to 20" with MIRI) revealing unprecedented details within the jet, the molecular outflow and the cavity. We detect, for the first time, the red-shifted jet within ~ 90 au from the source. Dozens of shock-excited forbidden lines are observed, including highly ionized species such as [Ne III] 15.5 micron, suggesting that the gas is excited by high velocity (> 80 km/s) shocks in a relatively high density medium. Images of H2 lines at different excitations outline a complex molecular flow, where a bright cavity, molecular shells, and a jet-driven bow-shock interact with and are shaped by the ambient conditions. Additional NIRCam 2 micron images resolve the HH46 IRS ~ 110 au binary system and suggest that the large asymmetries observed between the jet and the H2 wide angle emission could be due to two separate outflows being driven by the two sources. The spectra of the unresolved binary show deep ice bands and plenty of gaseous lines in absorption, likely originating in a cold envelope or disk. In conclusion, JWST has unraveled for the first time the origin of the HH46 IRS complex outflow demonstrating its capability to investigate embedded regions around young stars, which remain elusive even at near-IR wavelengths.

We used magnetograms acquired with the {\it Helioseismic and Magnetic Imager} (HMI) on board the {\it Solar Dynamics Observatory} (SDO) to calculate and analyze spatial correlation functions and the multi-fractal spectra in solar active regions (ARs). The analysis was performed for two very different types of ARs: i) simple bipolar magnetic structures with regular orientation (the magneto-morphological class A1), and ii) very complex multi-polar ARs (the magneto-morphological class B3). All ARs were explored at the developed phase during flareless periods. For correlation functions, the power-law and exponential approximations were calculated and compared. It was found that the exponential law holds for the correlation functions of both types of ARs within spatial scales of 1-36~Mm, while the power law failed to approximate the observed correlation functions. The property of multi-fractality was found in all ARs, being better pronounced for the complex B3-class ARs. Our results might imply that photospheric magnetic fields of an AR is a self-organized system, which, however, does not exhibit properties of self-organized criticality (SOC), and its fractal properties are an attribute of more broad (than SOC only) class of non-linear systems.

In this paper, we conduct a multi-frequency analysis of the gamma-ray bright blazar 1308+326 from February 2013 to March 2020, using the Korean VLBI Network at 22 and 43 GHz and gamma-ray data from the Fermi Large Area Telescope (LAT). Our findings reveal spectral variations around the 2014 gamma-ray flare, aligning with the shock-in-jet model. A strong correlation is observed between gamma-ray and 43 GHz emissions, with a 27-day lag in the VLBI core light curve, indicating a 50-day delay from the beginning of a specific radio flare to the gamma-ray peak. This radio flare correlates with a new jet component, suggesting the 2014 gamma-ray flare resulted from its interaction with a stationary component. Our analysis indicates the 2014 gamma-ray flare originated 40-63 parsecs from the central engine, with seed photons for the gamma-ray emission unlikely from the broad-line region.

Within the disk-corona model, it is natural to expect that a fraction of reflection photons from the disk are Compton scattered by the hot corona (reflection Comptonization), even if this effect is usually ignored in X-ray reflection spectroscopy studies. We study the effect by using NICER and NuSTAR data of the Galactic black hole EXO 1846-031 in the hard-intermediate state with the model SIMPLCUTX. Our analysis suggests that a scattered fraction of order 10% is required to fit the data, but the inclusion of reflection Comptonization does not change appreciably the measurements of key-parameters like the black hole spin and the inclination angle of the disk.

It has been observed that many relativistic jets display a kind of cork-screw-like precession. Numerical simulations has suggested that such kind of precession may originate from the precession of the disk. In this work, we introduce an analytical model to describe the precession and split of a tilted, geometrically thin disk. We consider the Lense-Thirring effect from the central (primary) black hole (BH) and the gravitational effect from the companion (secondary) BH far away from the center, both of which could induce the precession of the accretion disk around the spin axis of central black hole. We propose the splitting conditions that when the rate of viscous diffusion cannot catch up with the dynamical frequency at a certain layer of fluid, the disk would split into two parts which precess independently. We presume that the precessions of the inner and outer disks are in accord with the rotation and precession of jet, respectively. By matching the frequencies of the disks to the observed frequencies of jet in the cork-screw-like precession and considering the splitting condition, we are allowed to read four parameters, the innermost radius ($r_{\rm in}$), the outermost radius ($r_{\rm out}$) of the disk, the initial splitting radius ($r_{\rm sp,0}$), and the inflow speed magnitude($\beta$), of the disk. We apply this model to OJ 287. Moreover, considering the inward shrinking of the disks, we find the time variation of the precession angle of jet. This time variation presents a unique feature of our model, which could be distinguishable in the future observation.

Accretion disks are highly unstable to magnetic instabilities driven by shear flow, where classically, the axisymmetric, weak-field Magneto-Rotational Instability (MRI) has received much attention through local WKB approximations. In contrast, discrete non-axisymmetric counterparts require a more involved analysis through a full global approach to deal with the influence of the nearby magnetohydrodynamic (MHD) continua. Recently, rigorous MHD spectroscopy identified a new type of an ultra-localised, non-axisymmetric instability in global disks with super-Alfv\'enic flow. These Super-Alfv\'enic Rotational Instabilities (SARIs) fill vast unstable regions in the complex eigenfrequency plane with (near-eigen)modes that corotate at the local Doppler velocity and are radially localised between Alfv\'enic resonances. Unlike discrete modes, they are utterly insensitive to the radial disk boundaries. In this work, we independently confirm the existence of these unprecedented modes using our novel spectral MHD code Legolas reproducing and extending our earlier study with detailed eigenspectra and eigenfunctions. We calculate growth rates of SARIs and MRI in a variety of disk equilibria, highlighting the impact of field strength and orientation, and find correspondence with analytical predictions for thin, weakly magnetised disks. We show that non-axisymmetric modes can significantly extend instability regimes at high mode numbers, with maximal growth rates comparable to the MRI. Furthermore, we explicitly show a region filled with quasi-modes whose eigenfunctions are extremely localised in all directions. These modes must be ubiquitous in accretion disks, and play a role in local shearing box simulations. Finally, we revisit recent dispersion relations in the Appendix, highlighting their relation to our global framework.

Aims: To showcase and characterise the rich phenomenology of temperature fluctuation patterns that are imprinted on the CMB by the gravitational wave memory (GWM) of massive black hole (BH) mergers. Methods: We analyse both individual binaries as well as populations of binaries, distributed in local cosmological boxes at a given redshift. Results: The magnitude of the temperature fluctuations scales primarily as a function of binary total mass and pattern angular scale, and accumulates as a random-walk process when populations of mergers are considered. Fluctuations of order $\sim 10^{-10}$ K are easily reached across scales of $\sim 1'$ to $\sim 1^{\circ}$ for realistic volumetric merger rates of 10$^{-3}$ Mpc$^{-3}$ Gyr$^{-1}$, as appropriate for massive galaxies at $z=1$. We determine numerically that GWM temperature fluctuations result in a universal power spectrum with a scaling of $P(k)\propto k^{-2.7}$. Conclusion: While not detectable given the limitations of current all-sky CMB surveys, our work explicitly shows how every black hole merger in the Universe left us its unique faint signature.

Near IR spectroscopic reverberation of Active Galactic Nuclei (AGN) potentially allows the infrared (IR) broad line region (BLR) to be reverberated alongside the disc and dust continua, while the spectra can also reveal details of dust astro-chemistry. Here, we describe results of a short pilot study (17 near-IR spectra over a 183 d period) for Mrk 509. The spectra give a luminosity-weighted dust radius of $\langle R_{\mathrm{d,lum}} \rangle = 186 \pm 4$ light-days for blackbody (large grain dust), consistent with previous (photometric) reverberation campaigns, whereas carbon and silicate dust give much larger radii. We develop a method of calibrating spectral data in objects where the narrow lines are extended beyond the slit width. We demonstrate this by showing our resultant photometric band light curves are consistent with previous results, with a hot dust lag at >40 d in the K band, clearly different from the accretion disc response at <20 d in the z band. We place this limit of 40 d by demonstrating clearly that the modest variability that we do detect in the H and K band does not reverberate on time-scales of less than 40 d. We also extract the Pa$\beta$ line light curve, and find a lag which is consistent with the optical BLR H$\beta$ line of $\sim$70-90 d. This is important as direct imaging of the near-IR BLR is now possible in a few objects, so we need to understand its relation to the better studied optical BLR.

The PRobe far-Infrared Mission for Astrophysics (PRIMA) concept aims to perform mapping with spectral coverage and sensitivities inaccessible to previous FIR space telescopes. PRIMA's imaging instrument, PRIMAger, provides unique hyperspectral imaging simultaneously covering 25-235 $\mu$m. We synthesise images representing a deep, 1500 hr deg$^{-2}$ PRIMAger survey, with realistic instrumental and confusion noise. We demonstrate that we can construct catalogues of galaxies with a high purity ($>95$ per cent) at a source density of 42k deg$^{-2}$ using PRIMAger data alone. Using the XID+ deblending tool we show that we measure fluxes with an accuracy better than 20 per cent to flux levels of 0.16, 0.80, 9.7 and 15 mJy at 47.4, 79.7, 172, 235 $\mu$m respectively. These are a factor of $\sim$2 and $\sim$3 fainter than the classical confusion limits for 72-96 $\mu$m and 126-235 $\mu$m, respectively. At $1.5 \leq z \leq 2$, we detect and accurately measure fluxes in 8-10 of the 10 channels covering 47-235 $\mu$m for sources with $2 \leq$ log(SFR) $\leq 2.5$, a 0.5 dex improvement on what might be expected from the classical confusion limit. Recognising that PRIMager will operate in a context where high quality data will be available at other wavelengths, we investigate the benefits of introducing additional prior information. We show that by introducing even weak prior flux information when employing a higher source density catalogue (more than one source per beam) we can obtain accurate fluxes an order of magnitude below the classical confusion limit for 96-235 $\mu$m.

The stellar rotation has an essential role in modifying the structure of the star and, therefore, the way these different interplays arise. On the other hand, changes in orbits impact the star's rotation and its evolution. The evolution of the star's rotation accounts for the angular momentum exchange with the planet and follows the effects of the internal transport of angular momentum and metallicity. Several models in the literature have aimed to find a theoretical way to study these interactions between the planet's orbital evolution and the star's rotation. Our work is a promising attempt to investigate these interactions from a model based on a new statistical approach. To this end, we propose a ``tidal interaction index'' that carries all the parameters of the star-planet system that can affect the transport of angular momentum and, consequently, the evolution of stellar rotation. This index is similar to the ``magnetic braking index'' whose most successful value equals 3, which expresses the seminal Skumunich law. Our model is computed for masses of the host star less than the Kraft limit for three orbital-rotation period regimes and the semi-major axis less than 1 AU. We consider planets with masses between 0.4M$_{\oplus}$ and 20M$_{\rm J}$ with orbital periods between 0.3 and 225 days. We show that the tidal index $q$ segregated by stellar mass without wind magnetic braking during the main-sequence phase is strongly anti-correlated with planetary mass. Finally, we conclude that in cases where planets retain less than 84\% of the total angular momentum within the system, the magnetic braking mechanism proves to be more effective than tidal interactions, irrespective of whether the planets' angular momentum surpasses that of the host star.

Context: Quasar variability has proven to be a powerful tool to constrain the properties of their inner engine and the accretion process onto supermassive black holes. Correlations between UV/optical variability and physical properties have been long studied with a plethora of different approaches and time-domain surveys, although the detailed picture is not yet clear. Aims: We analysed archival data from the SDSS Stripe-82 region to study how the quasar power spectral density (PSD) depends on the black hole mass, bolometric luminosity, accretion rate, redshift, and rest-frame wavelength. We developed a model-independent analysis framework that could be easily applied to upcoming large surveys such as the Legacy Survey of Space and Time (LSST). Methods: We used light curves of 8042 spectroscopically confirmed quasars, observed in at least six yearly seasons in five filters ugriz. We split the sample into bins of similar physical properties containing at least 50 sources, and we measured the ensemble PSD in each of them. Results: We find that a simple power law is a good fit to the power spectra in the frequency range explored. Variability does not depend on redshift at a fixed wavelength. Instead, both PSD amplitude and slope depend on the black hole mass, accretion rate, and rest-frame wavelength. We provide scaling relations to model the observed variability as a function of the physical properties, and discuss the possibility of a universal PSD shape for all quasars, where frequencies scale with the black hole mass, while normalization and slope(s) are fixed (at any given wavelength and accretion rate).

We recently introduced three new parameters that describe the shape of the normalized cumulative radial distribution (nCRD) of the innermost stars in globular clusters and trace the clusters dynamical evolution. Here we extend our previous investigations to the case of a large set of Monte Carlo simulations of globular clusters, started from a broad range of initial conditions. All the models are analyzed at the same age of 13 Gyr, when they have reached different evolutionary phases. The sample of models is well representative of the structural properties of the observed population of Galactic globular clusters. We confirm that the three nCRD parameters are powerful tools to distinguish systems in early stages of dynamical evolution, from those that already experienced core collapse. They might also help disentangle clusters hosting a low-mass intermediate-mass black hole of a few hundred solar masses, from cases with large concentrations of dark remnants in their centers. With respect to other dynamical indicators, the nCRD parameters offer the advantage of being fully empirical and easier to measure from observational data.

The cosmic merger history of supermassive black hole binaries (SMBHBs) is expected to produce a low-frequency gravitational wave background (GWB). Here we investigate how signs of the discrete nature of this GWB can manifest in pulsar timing arrays through excursions from, and breaks in, the expected $f_{\mathrm{GW}}^{-2/3}$ power-law of the GWB strain spectrum. To do this, we create a semi-analytic SMBHB population model, fit to NANOGrav's 15 yr GWB amplitude, and with 1,000 realizations we study the populations' characteristic strain and residual spectra. Comparing our models to the NANOGrav 15 yr spectrum, we find two interesting excursions from the power-law. The first, at $2 \; \mathrm{nHz}$, is below our GWB realizations with $p$-value significance $p = 0.05$ to $0.06$ ($\approx 1.8 \sigma - 1.9 \sigma$). The second, at $16 \; \mathrm{nHz}$, is above our GWB realizations with $p = 0.04$ to $0.15$ ($\approx 1.4 \sigma - 2.1 \sigma$). We explore the properties of a loud SMBHB which could cause such an excursion. Our simulations also show that the expected number of SMBHBs decreases by three orders of magnitude, from $\sim 10^6$ to $\sim 10^3$, between $2\; \mathrm{nHz}$ and $20 \; \mathrm{nHz}$. This causes a break in the strain spectrum as the stochasticity of the background breaks down at $26^{+28}_{-19} \; \mathrm{nHz}$, consistent with predictions pre-dating GWB measurements. The diminished GWB signal from SMBHBs at frequencies above the $26$~nHz break opens a window for PTAs to detect continuous GWs from individual SMBHBs or GWs from the early universe.

The Jeans equations do not form a closed system, and to solve them a parametrization relating the velocity moments is often adopted. For axisymmetric models, a phenomenological choice (the "$b$-ansatz") is widely used for the relation between the vertical ($\sigma_z^2$) and radial ($\sigma_R^2$) components of the velocity dispersion tensor, thus breaking their identity present in two-integral systems. However, the way in which the ansatz affects the resulting kinematical fields can be quite complicated, so that the analysis of these fields is usually performed only after numerically computing them. We present here a general procedure to study the properties of the ansatz-dependent fields $\overline{v_{\varphi}^2}$, $\Delta = \overline{v_{\varphi}^2} - \sigma_z^2$ and $\Delta_R = \overline{v_{\varphi}^2} - \sigma_R^2$. Specifically, the effects of the $b$-ansatz can be determined before solving the Jeans equations once the behaviour over the ($R,z$)-plane of three easy-to-build ansatz-independent functions is known. The procedure also constrains the ansatz to exclude unphysical results (as a negative $\overline{v_{\varphi}^2}$). The method is illustrated by discussing the cases of three well-known galaxy models: the Miyamoto & Nagai and Satoh disks, and the Binney logarithmic halo, for which the regions and the constraints on the ansatz values can be determined analytically; a two-component (Miyamoto & Nagai plus logarithmic halo) model is also discussed.

We propose a second-order statistic parameter $\varepsilon$, the relative occurrence rate between hot and cold Jupiters ($\varepsilon=\eta_{\rm HJ}/\eta_{\rm CJ}$), to probe the migration of gas giants. Since the planet occurrence rate is the combined outcome of the formation and migration processes, a joint analysis of hot and cold Jupiter frequency may shed light on the dynamical evolution of giant planet systems. We first investigate the behavior of $\varepsilon$ as the stellar mass changes observationally. Based on the occurrence rate measurements of hot Jupiters ($\eta_{\rm HJ}$) from the TESS survey and cold Jupiters ($\eta_{\rm CJ}$) from the CLS survey, we find a tentative trend (97% confidence) that $\varepsilon$ drops when the stellar mass rises from $0.8$ to $1.4\ M_\odot$, which can be explained by different giant planet growth and disk migration timescales around different stars. We carry out planetesimal and pebble accretion simulations, both of which could reproduce the results of $\eta_{\rm HJ}$, $\eta_{\rm CJ}$ and $\varepsilon$. Our findings indicate that the classical core accretion + disk migration model can explain the observed decreasing trend of $\varepsilon$. We propose two ways to increase the significance of the trend and verify the anti-correlation. Future works are required to better constrain $\varepsilon$, especially for M dwarfs and for more massive stars.

One-dimensional, semi-empirical models of the solar atmosphere are widely employed in numerous contexts within solar physics, ranging from the determination of element abundances and atomic parameters to studies of the solar irradiance and from Stokes inversions to coronal extrapolations. These models provide the physical parameters (i.e. temperature, gas pressure, etc.) in the solar atmosphere as a function of the continuum optical depth $\tau_{\rm c}$. The transformation to the geometrical $z$ scale (i.e. vertical coordinate) is provided via vertical hydrostatic equilibrium. Our aim is to provide updated, one-dimensional, semi-empirical models of the solar atmosphere as a function of $z,$ but employing the more general case of three-dimensional magneto-hydrostatic equilibrium (MHS) instead of vertical hydrostatic equilibrium (HE). We employed a recently developed Stokes inversion code that, along with non-local thermodynamic equilibrium effects, considers MHS instead of HE. This code is applied to spatially and temporally resolved spectropolarimetric observations of the quiet Sun obtained with the CRISP instrument attached to the Swedish Solar Telescope. We provide average models for granules, intergranules, dark magnetic elements, and overall quiet-Sun as a function of both $\tau_{\rm c}$ and $z$ from the photosphere to the lower chromosphere. We demonstrate that, in these quiet-Sun models, the effect of considering MHS instead of HE is negligible. However, employing MHS increases the consistency of the inversion results before averaging. We surmise that in regions with stronger magnetic fields (i.e. pores, sunspots, network) the benefits of employing the magneto-hydrostatic approximation will be much more palpable.

In this study, we explore model independent constraints on the universe kinematics up to the snap and jerk hierarchical terms. To do so, we consider the latest Baryon Acoustic Oscillation (BAO) release provided by the DESI collaboration, tackling the $r_d$ parameter to span within the range $[144,152]$ Mpc, with fixed step, $\delta r_d=2$ Mpc, aligning with Planck and DESI results. Thus, employing Monte Carlo Markov chain analyses, we place stringent constraints on the cosmographic series, incorporating three combinations of data catalogs: the first BAO with observational Hubble data, the second BAO with type Ia supernovae, and the last including all three data sets. Our results conclusively constrain the cosmographic series, say the deceleration $q_0$, the jerk $j_0$, and the snap $s_0$ parameters, at the $2$--$\sigma$ level, showcasing a significant departure on $j_0$ even at $1$--$\sigma$ confidence level, albeit being compatible with the $\Lambda$CDM paradigm on $q_0$ and $s_0$, at $2$--$\sigma$ level. Analogously, the $h_0$ tension appears alleviated in the second hierarchy, say including snap. Finally, a direct comparison with the $\Lambda$CDM, $w$CDM models and the Chevallier-Polarski-Linder parametrization is reported, definitively favoring the wCDM scenario.

Nowadays, at least two relics of the Big Bang have survived - the cosmological microwave background (CMB) and the cosmological neutrino background (C$\nu$B). Being the second most abundant particle in the Universe, the neutrino has a significant impact on its evolution from the Big Bang to the present day. Neutrinos affect the following cosmological processes: the expansion rate of the Universe, its chemical and isotopic composition, the CMB anisotropy and the formation of the large-scale structure of the Universe. Another relic neutrino background is theoretically predicted, it consists of non-equilibrium antineutrinos of Primordial Nucleosynthesis arising as a result of the decays of neutrons and tritium nuclei. Such antineutrinos are an indicator of the baryon asymmetry of the Universe. In addition to experimentally detectable active neutrinos, the existence of sterile neutrinos is theoretically predicted to generate neutrino masses and explain their oscillations. Sterile neutrinos can also solve such cosmological problems as the baryonic asymmetry of the Universe and the nature of dark matter. The recent results of several independent experiments point to the possibility of the existence of a light sterile neutrino. However, the existence of such a neutrino is inconsistent with the predictions of the Standard Cosmological Model. The inclusion of a non-zero lepton asymmetry of the Universe and/or increasing the energy density of active neutrinos can eliminate these contradictions and reconcile the possible existence of sterile neutrinos with Primordial Nucleosynthesis, the CMB anisotropy, and also reduce the H$_0$-tension. In this brief review, we discuss the influence of the physical properties of active and sterile neutrinos on the evolution of the Universe from the Big Bang to the present day.

Recent work suggests that inwardly propagating internal gravity waves (IGWs) within a star can be fully converted to outward magnetic waves (MWs) if they encounter a sufficiently strong magnetic field. The resulting magnetic waves dissipate as they propagate outward to regions with lower Alfv\'{e}n velocity. While tidal forcing is known to excite IGWs, this conversion and subsequent damping of magnetic waves has not been explored as a tidal dissipation mechanism. In particular, stars with sufficiently strong magnetic fields could fully dissipate tidally excited waves, yielding the same tidal evolution as the previously-studied ``travelling wave regime''. Here, we evaluate the viability of this mechanism using stellar models of stars with convective cores (F-type stars in the mass range of $1.2$-$1.6M_\odot$) which were previously thought to be weakly tidally dissipative (due to the absence of nonlinear gravity wave breaking). The criterion for wave conversion to operate is evaluated for each stellar mass using the properties of each star's interior along with estimates of the magnetic field produced by a convective core dynamo under the assumption of equipartition between kinetic (convective) and magnetic energies. Our main result is that this previously unexplored source of efficient tidal dissipation can operate in stars within this mass range for significant fractions of their lifetimes. This tidal dissipation mechanism appears to be consistent with the observed inspiral of WASP-12b, and more generally could play an important role in the orbital evolution of hot Jupiters -- and to lower mass ultra-short period planets -- orbiting F-type stars.

GQ Lup B is a forming brown dwarf companion ($M\sim10-30~M_J$) showing evidence for an infrared excess associated with a disk surronding the companion itself. Here we present mid-infrared (MIR) observations of GQ Lup B with the Medium Resolution Spectrograph (MRS) on JWST, spanning $4.8-11.7~\mu$m. We remove the stellar contamination using reference differential imaging based on principal component analysis (PCA), demonstrating that the MRS can perform high-contrast science. Our observations provide a sensitive probe of the disk surrounding GQ Lup B. We find no sign of a silicate feature, similar to other disk surrounding very low mass objects, which likely implies significant grain growth ($a_{\mathrm{min}}\gtrsim5~\mu$m), and potentially dust settling. Additionally, we find that if the emission is dominated by an inner wall, the disk around the companion might have an inner cavity larger than the one set by sublimation. Conversely, if our data probe the emission from a thin flat disk, we find the disk to be very compact. More observations are required to confirm this finding and assess the vertical structure of the disk. This approach paves the path to the future study of circumplanetary disks and their physical properties. Our results demonstrate that MIR spectroscopic observations can reveal the physical characteristics of disks around forming companions, providing unique insights into the formation of giant planets, brown dwarfs and their satellites.

The search for periodicity in the multi-wavelength high variable emission of blazars is a key feature to understand dynamical processes at work in this class of active galactic nuclei. The blazar PG 1553+113 is an attractive target due to the evidence of periodic oscillations observed at different wavelengths, with a solid proof of a 2.2-year modulation detected in the $\gamma$-ray, UV and optical bands. We aim at investigating the variability pattern of the PG 1553+113 X-ray emission using a more than 10-years long light curve, in order to robustly assess the presence or lack of a periodic behavior whose evidence is only marginal so far. We conducted detailed statistical analyses, studying in particular the variability properties of the X-ray emission of PG 1553+113 by computing the Lomb-Scargle periodograms, which are suited for the analyses of unevenly sampled time series, and adopting epoch folding techniques. We find out a modulation pattern in the X-ray light curve of PG 1553+113 with a period of $\sim$1.4 years, about 35% shorter than the one observed in the $\gamma$-ray domain. Our finding is in agreement with the recent spectro-polarimetric analyses and supports the presence of more dynamical phenomena simultaneously at work in the central engine of this quasar.

Utilizing high-cadence and continuous g- and r-band data over three nights acquired from the 3.6-meter Canada France Hawaii Telescope (CFHT) aimed to find short-duration microlensing events, we conduct a systematic search for variables, transients, and asteroids across a $\sim1^\circ$ field of view of the Andromeda Galaxy (M 31). We present a catalog of 5859 variable stars, yielding the most extensive compilation of short-period variable sources of M 31. We also detected 19 flares, predominantly associated with foreground M dwarfs in the Milky Way. In addition, we discovered 17 previously unknown asteroid candidates, and we subsequently reported them to the Minor Planet Center. Lastly, we report a microlensing event candidate C-ML-1 and present a preliminary analysis.

We present optical spectroscopy of the 12th-mag central star of the planetary nebula (PN) Patchick 27 (Pa 27), obtained during a survey of faint PN nuclei (PNNi) with the Low-Resolution Spectrograph (LRS2) of the Hobby-Eberly Telescope. The optical spectrum of Pa 27 is that of a K0 III red giant with rotationally broadened lines. However, the star is detected in the near-ultraviolet (near-UV) with GALEX, showing that a hot binary component is also present. The spectral-energy distribution from the near-UV to the mid-infrared can be fitted with a combination of the K0 III giant and a hot PNN with an effective temperature of about 50,000 K. Photometric observations of Pa 27, both ground-based and from TESS, show a low-amplitude sinusoidal variation with a period of 7.36 days, probably due to starspots on a rotating and magnetically active cool giant. Pa 27 is a new member of the rare class of "Abell 35-type central stars," which are binary PNNi consisting of a spotted late-type star and a hot pre-white dwarf. They are likely the result of a situation where an AGB star ejects its outer layers in a dense wind, part of which is captured by a distant companion, spinning up its rotation by accretion of material and angular momentum. We suggest several useful follow-up observations.

Observations point to old white dwarfs (WDs) accreting metals at a relatively constant rate over 8~Gyrs. Exo-Oort clouds around WDs have been proposed as potential reservoirs of materials, with galactic tide as a mechanism to deliver distant comets to the WD's Roche limit. In this work, we characterise the dynamics of comets around a WD with a companion having semi-major axes on the orders of 10 - 100 AU. We develop simulation techniques capable of integrating a large number ($10^8$) of objects over a 1 Gyr timescale. Our simulations include galactic tide and are capable of resolving close-interactions with a massive companion. Through simulations, we study the accretion rate of exo-Oort cloud comets into a WD's Roche limit. We also characterise the dynamics of precession and scattering induced on a comet by a massive companion. We find that (i) WD pollution by an exo-Oort cloud can be sustained over a Gyr timescale, (ii) an exo-Oort cloud with structure like our own Solar System's is capable of delivering materials into an isolated WD with pollution rate $\sim 10^8 \mathrm{~g~s^{-1}}$, (iii) adding a planetary-mass companion reduces the pollution rate to $\sim 10^7 \mathrm{~g~s^{-1}}$, and (iv) if the companion is stellar-mass, with $M_p \gtrsim 0.1 M_\odot$, the pollution rate reduces to $\sim 3 \times 10^5 \mathrm{~g~s^{-1}}$ due to a combination of precession induced on a comet by the companion, a strong scattering barrier, and low-likelihood of direct collisions of comets with the companion.

We develop a photometric search method for identifying smouldering galaxies at $5< z < 8$, which are defined to have weak emission lines and thus generally have low specific star formation rates and may even be in a state of (temporary) quiescence. The deep NIRCam imaging (${\sim}29.5$ AB mag, 5$\sigma$) from the JADES second data release is essential for finding these systems, as they are faint, relatively quiescent dwarf galaxies ($M_* \sim 10^{8}$-$10^9$ $\mathrm{M}_\odot)$ in the Epoch of Reionisation (EoR). Moreover, medium-band imaging is key, enabling a clear identification of the lack of emission lines in these galaxies, thus betraying their dormant flame. Owing to the young age of the Universe, combined with the likely bursty star formation in these first dwarf galaxies, conventional colour-selection methods like the UVJ diagram likely miss a large fraction of the quiescent population in the EoR. Indeed, we find that smouldering galaxies constitute a considerable fraction (0.10-0.35) of the EoR dwarf galaxy population ($M_* \sim 10^{8}$-$10^{9}$ $\mathrm{M}_\odot$). As predicted by simulations, these first dwarf galaxies are fragile, the star formation in their shallow potential wells easily snuffed out by feedback-driven winds triggered by secular or merger-driven starbursts, with the smouldering fraction increasing with decreasing stellar mass. Finally, we provide observational constraints on the smouldering galaxy comoving number density (${\sim}10^{-4}$-$10^{-5}$ dex$^{-1}$ Mpc$^{-3}$), which, although hampered by incompleteness, should aid in our understanding of the primordial baryon cycle, as current simulations greatly disagree on whether these systems are rare (${\sim}1\%$) or common (${\sim}50\%$) in the EoR.

The diverse Lyman-alpha (Ly$\alpha$) line profiles are essential probes of gas in and around galaxies. While isotropic models can successfully reproduce a range of Ly$\alpha$ observables, the correspondence between the model and actual physical parameters remains uncertain. We investigate the effect of anisotropies of Ly$\alpha$ escape using a simplified setup: a hole (fractional size $\tilde s$) within a semi-infinite slab with constant column density. Due to the slab's high line-centre optical depth ($\tau_0\gtrsim 10^{5-6}$), most photons should escape through the empty channel. However, our numerical findings indicate that only a fraction $\sim \tilde s$ of photons exit through this channel. To explain this puzzle, we developed an analytical model describing the scattering and transmission behaviour of Ly$\alpha$ photons in an externally illuminated slab. Our findings show that the number of scatterings per reflection follows a L\'evy distribution ($\propto N^{-3/2}$). This means that the mean number of scatterings is orders of magnitude greater than expectations, facilitating a shift in frequency and the subsequent photon escape. Our results imply that Ly$\alpha$ photons are more prone to traverse high-density gas and are surprisingly less biased to the `path of least resistance'. Hence, Ly$\alpha$ can trace an averaged hydrogen distribution rather than only low-column density `channels'.

In this proceeding we review and expand on our recent work investigating the constancy of the absolute magnitude $M_B$ of Type Ia supernovae. In it, we used baryonic acoustic oscillations (BAO) to calibrate the supernova data and to check whether the resulting $M_B$ is constant. We used non-parametric methods like Gaussian processes and artificial neural networks to reconstruct $M_B(z)$. Here we elaborate on the results by putting them in the context of other studies investigating possible non-constant $M_B$ and the impact of the distance-duality relation. We also present some numerical details on the calculations in the original paper and new non-parametric reconstructions, including a conservative model-independent fit, confirming its main results. Notably, we see that $M_B$ remains constant within $1\sigma$, with a possible jump around $z = 0.01 - 0.15$. Furthermore, the observed distribution of $M_B(z)$ cannot be described by a single Gaussian, displaying multiple peaks and tails. The choice of the only remaining parameter -- the sound horizon $r_d$ leads to a tension in the $M_B-r_d$ plane. Fitting different non-constant $M_B(z)$ models does not significantly improve the fit and there is no preference for any of the models by the statistical measures we employ.

We apply the in-in formalism to address the question of whether the size of the one-loop spectrum of curvature fluctuations in ultra-slow-roll inflation models designed for producing a large population of primordial black holes implies a breakdown of perturbation theory. We consider a simplified piece-wise description of inflation, in which the ultra-slow-roll phase is preceded and followed by slow-roll phases linked by transitional periods. We work in the $\delta\phi$-gauge, including all relevant cubic and quartic interactions and the necessary counterterms to renormalize the ultraviolet divergences, regularized by a cutoff. The ratio of the one-loop to the tree-level contributions to the spectrum of curvature perturbations is controlled by the duration of the ultra-slow-roll phase and of the transitions. Our results indicate that perturbation theory does not necessarily break in well-known models proposed to account for all the dark matter in the form of primordial black holes.

In this paper, we present the first comprehensive CMB data analysis of cosmological collider physics. New heavy particles during inflation can leave imprints in the primordial correlators which are observable in today's cosmological surveys. This remarkable detection channel provides an unsurpassed opportunity to probe new physics at extremely high energies. Here we initiate the search for these relic signals in the cosmic microwave background (CMB) data from the Planck legacy release. On the theory side, guided by recent progress from the cosmological bootstrap, we first propose a family of analytic bispectrum templates that incorporate the distinctive signatures of cosmological collider physics. Our consideration includes the oscillatory signals in the squeezed limit, the angular dependence from spinning fields, and several new shapes from nontrivial sound speed effects. On the observational side, we apply the recently developed pipeline, CMB Bispectrum Estimator (CMB-BEST), to efficiently analyze the three-point statistics and search directly for these new templates in the Planck 2018 temperature and polarization data. We report stringent CMB constraints on these new templates. Furthermore, we perform parameter scans to search for the best-fit values with maximum significance. For a benchmark example of collider templates, we find $f_{NL}=-91\pm40$ at the $68\%$ confidence level. After accounting for the look-elsewhere effect, the biggest adjusted significance we get is $1.8\sigma$. In general, we find no significant evidence of cosmological collider signals in the Planck data. However, this innovative analysis demonstrates the potential for discovering new heavy particles during inflation in forthcoming cosmological surveys.

A sample of quasars has been recently assembled to investigate the non-linear relation between their monochromatic luminosities at 2500{\AA}, and 2 keV and to exploit quasars as a new class of standardized candles. The use of this technique for cosmological purposes relies on the non-evolution with redshift of the UV-optical spectral properties of quasars, as well as on the absence of possible contaminants such as dust extinction and host-galaxy contribution. We address these possible issues by analysing the spectral properties of our cosmological quasar sample. We produced composite spectra in different bins of redshift and accretion parameters (black hole mass, bolometric luminosity), to investigate any possible evolution of the spectral properties of the continuum of the composites with these parameters. We found a remarkable similarity amongst the various stacked spectra. The overall shape of the continuum does not show any statistically significant trend with the accretion parameters nor with the redshift. The composite spectrum of our quasar sample is consistent with negligible levels of both intrinsic reddening (with a colour excess E(B-V)< 0.01) and host-galaxy emission (less than 10%) in the optical. We tested whether unaccounted dust extinction could explain the discrepancy between our cosmographic fit of the Hubble-Lemaitre diagram and the concordance {\Lambda}CDM model. The average colour excess required to solve the tension should increase with redshift up to unphysically high values (E(B-V)=0.1 at z>3) that would imply that the intrinsic emission of quasars is much bluer and more luminous than ever reported in observed spectra. The similarity of quasar spectra across the parameter space excludes a significant evolution of the average continuum properties with any of the explored parameters, confirming the reliability of our sample for cosmological applications.

We investigate the generation of the baryon asymmetry within the framework of cosmological gra\-vi\-ta\-tional particle production, employing the Bogoliubov approach. We examine two well-known baryogenesis scenarios, namely baryogenesis in Grand Unified Theories (GUT) and leptogenesis, while considering reheating temperatures sufficiently low for thermal processes to be negligible. Considering $\alpha-$attractor T-models for the inflaton potential, we demonstrate that GUT baryogenesis from scalar decays can be successful across a large range of conformal couplings with gravity, without necessitating substantial levels of CP violation. In the case of leptogenesis, we find that the reheating temperature should be $T_{\rm RH}\lesssim 10^{6}~{\rm GeV}$ for right-handed neutrino masses $M_1 \lesssim 6 \times 10^{12}~{\rm GeV}$ to generate the observed asymmetry.

We propose an extension of General Relativity (GR) based on a space-time foliation by three-dimensional space-like hypersurfaces labeled by the Khronon scalar field $\tau$. We show that this theory (i) leads to modified Newtonian dynamics (MOND) at galactic scales for stationary systems; (ii) recovers GR plus a cosmological constant in the strong field regime; (iii) is in agreement with the standard cosmological model and the observed cosmic microwave background anisotropies at linear cosmological scales, where the theory reduces to a subset of the generalized dark matter (GDM) model. We compute the second order action on a Minkowski background and show that it contains the usual tensor modes of GR and a scalar degree of freedom with dispersion relation $\omega=0$. We find that the deconstrained Hamiltonian is bounded from below for wavenumbers larger than $\sim 10^{-31}\,\text{eV}$ and unbounded for smaller wavenumbers.

Optical interferometric imaging enables astronomical observation at extremely high angular resolution. The necessary optical information for imaging, such as the optical path differences and visibilities, is easy to extract from fringes generated by the combination of two beams. With more than two apertures, the image-plane interference pattern becomes an increasingly indistinguishable mixture of fringe spacings and directions. For decades, the state-of-the-art approaches for obtaining two-aperture fringes from an interferometer array composed of many apertures are limited to pairwise combinations using bulk optics. Here, we derive and demonstrate a fringe disentanglement theory that can digitally transform the interference pattern of N apertures to N(N-1)/2 pairwise fringes without any optics, thus providing straightforward methods of information acquisition for interferometers. We demonstrate applications of our technique by both simulation and experiment, showing that this theory can be used for simultaneously sensing pistons and determining the individual visibilities of all combining apertures. Furthermore, we use the proposed theory to phase a 1.5-meter segmented flat telescope, demonstrating its validity for engineering implementation. This theory may not only benefit optical imaging but also interferometry-based measurements, by providing an exceptional capability to simplify the interferometric output generated by a system of many apertures.

From a fractal perspective, the entropy bound of gravitational systems undergoes changes. Furthermore, in the cosmological setting, the conservation law of a perfect fluid is also altered in such systems, affecting spatial elements like volume, area, and radius. By applying the first law of thermodynamics and deriving the Friedmann equations, we can gain insight into the evolution of such a fractal cosmos. However, observations continue to necessitate the existence of a dark energy source. To address this, in this article, we have created a novel fractal $\Lambda$CDM cosmological model and determined the fractal cosmological observables. We show that the spatial fractal dimension is two, and the age of the Universe is 13.91 Gyr, by fitting the model's parameters to cosmological data.

The Kerr spacetime is symmetric with respect to a well-defined equatorial plane. When testing the equatorial reflection symmetry of an isolated black hole, one is at the same time testing the Kerr hypothesis in General Relativity. In this work, we investigate the possible observational features when a Keplerian disk is surrounding a rotating black hole without reflection symmetry. When such symmetry is broken, generically, the photon trajectories around the black hole and the Keplerian orbits on the accretion disk are distorted vertically away from the equatorial plane by an amount that depends on their distance to the black hole. In the reflection asymmetric spacetime we are considering, these two kinds of orbits are distorted in opposite directions. Interestingly, while the size and shape of black hole shadows closely resemble those of Kerr black holes, distinct observational characteristics can emerge in the disk image and emission line profiles. When observing the disk edge-on, a pronounced concave shape may appear along its innermost edge on the incoming side. Furthermore, distinctive horn-like features might be observed on the spectral line profile at the blue-shifted side. These special features can serve as compelling indicators of the reflection asymmetry present in rotating black holes.

The null energy condition (NEC) is a cornerstone of general relativity, and its violation could leave observable imprints in the cosmic gravitational wave spectrum. Theoretical models suggest that NEC violations during inflation can amplify the primordial tensor power spectrum, leading to distinct features in the stochastic gravitational wave background (SGWB). In this work, we search for these NEC-violating signatures in the SGWB using data from Advanced LIGO and Advanced Virgo's first three observing runs. Our analysis reveals no statistically significant evidence of such signals, allowing us to place stringent upper limits on the tensor power spectrum amplitude, $P_{T,2}$, during the second inflationary stage. Specifically, we find that $P_{T,2} \lesssim 0.15$ at a $95\%$ confidence level. Notably, this upper limit is consistent with constraints derived from pulsar timing array observations, reinforcing the hypothesis that NEC violations during inflation could explain the signal detected by pulsar timing arrays. Our findings contribute to a deeper understanding of the early Universe and highlight the potential of current and future gravitational wave experiments in probing the physics of inflation and NEC violations.

We study lensing of gravitational waves by a black hole in the deep wave optics regime, i.e. when the wavelength is much larger than the black hole Schwarzschild radius. We apply it to triple systems, with a binary of stellar mass objects in the inspiraling phase orbiting around a central massive black hole. We describe the full polarisation structure of the wave and derive predictions for the polarisation modes of the scattered wave measured by the observer. We show that lensing in the wave optics regime is not helicity preserving, as opposed to lensing in the geometric optics regime. The amplitude of the total wave is modulated due to interference between the directly transmitted and lensed components. The relative amplitude of the modulation is fixed by the lensing geometry and can reach unity in the most favourable settings. This indicates that wave optics lensing is potentially detectable by LISA for sufficiently high SNR systems. Our findings show that in the wave optics regime it is necessary to go beyond the usual lensing description where the amplification factor is assumed to be the same for both helicity modes. While motivated by GW190521 and the AGN formation scenario, our results apply more broadly to stellar-mass binaries orbiting a third body described as a Schwarzschild black hole, with a period comparable to the GW observation time.