Papers for Tuesday, Jun 21 2022

We propose a novel design for a lightweight, high-performance space-based solar power array combined with power beaming capability for operation in geosynchronous orbit and transmission of power to Earth. We use a modular configuration of small, repeatable unit cells, called tiles, that each individually perform power collection, conversion, and transmission. Sunlight is collected via lightweight parabolic concentrators and converted to DC electric power with high efficiency III-V photovoltaics. Several CMOS integrated circuits within each tile generates and controls the phase of multiple independently-controlled microwave sources using the DC power. These sources are coupled to multiple radiating antennas which act as elements of a large phased array to beam the RF power to Earth. The power is sent to Earth at a frequency chosen in the range of 1-10 GHz and collected with ground-based rectennas at a local intensity no larger than ambient sunlight. We achieve significantly reduced mass compared to previous designs by taking advantage of solar concentration, current CMOS integrated circuit technology, and ultralight structural elements. Of note, the resulting satellite has no movable parts once it is fully deployed and all beam steering is done electronically. Our design is safe, scalable, and able to be deployed and tested with progressively larger configurations starting with a single unit cell that could fit on a cube satellite. The design reported on here has an areal mass density of 160 g/m2 and an end-to-end efficiency of 7-14%. We believe this is a significant step forward to the realization of space-based solar power, a concept once of science fiction.

The famous "Wow" signal detected in 1977 remains arguably the most compelling SETI signal ever found. The original Big Ear data requires that the signal turned on/off over the span of ~3 minutes (time difference between the dual antennae), yet persisted for 72 seconds (duration of a single beam sweep). Combined with the substantial and negative follow-up efforts, these observations limit the allowed range of signal repeat schedules, to the extent that one might question the credibility of the signal itself. Previous work has largely excluded the hypothesis of a strictly periodic repeating source, for periods shorter than 40 hours. However, a non-periodic, stochastic repeater remains largely unexplored. Here, we employ a likelihood emulator using the Big Ear observing logs to infer the probable signal properties under this hypothesis. We find that the maximum a-posteriori solution has a likelihood of 32.3%, highly compatible with the Big Ear data, with a broad 2 $\sigma$ credible interval of signal duration 72 secs < T < 77 mins and mean repeat rate 0.043 1/days < $\lambda$ < 59.8 1/days. We extend our analysis to include 192 hours of subsequent observations from META, Hobart and ATA, which drops the peak likelihood to 1.78%, and thus in tension with the available data at the 2.4 $\sigma$ level. Accordingly, the Wow signal cannot be excluded as a stochastic repeater with available data, and we estimate that 62 days of accumulated additional observations would be necessary to surpass 3 $\sigma$ confidence.

A growing number of core collapse supernovae (SNe) which show evidence for interaction with dense circumstellar material (CSM) are accompanied by ``precursor'' optical emission rising weeks to months prior to the explosion. The precursor luminosities greatly exceed the Eddington limit of the progenitor star, implying they are accompanied by substantial mass-loss. Here, we present a semi-analytic model for SN precursor light curves which we apply to constrain the properties and mechanisms of the pre-explosion mass-loss. We explore two limiting mass-loss scenarios: (1) an ``eruption'' arising from shock break-out following impulsive energy deposition below the stellar surface; (2) a steady ``wind'' due to sustained heating of the progenitor envelope . The eruption model, which resembles a scaled-down version of Type IIP SNe, can explain the luminosities and timescales of well-sampled precursors, for ejecta masses $\sim 0.1-1\,M_{\odot}$ and velocities $\sim 100-1000\,\rm km\,s^{-1}$. By contrast, the steady-wind scenario cannot explain the highest precursor luminosities $\gtrsim10^{41}\,\rm erg\,s^{-1}$, under the constraint that the total ejecta mass not exceed the entire progenitor mass (though the less-luminous SN 2020tlf precursor can be explained by a mass-loss rate $\sim1\,M_{\odot}\,\rm yr^{-1}$). However, shock interaction between the wind and pre-existing (earlier ejected) CSM may boost its radiative efficiency and mitigate this constraint. In both eruption and wind scenarios the precursor ejecta forms compact ($\lesssim10^{15}$ cm) optically-thick CSM at the time of core collapse; though only directly observable via rapid post-explosion spectroscopy ($\lesssim$ few days before being overtaken by the SN ejecta), this material can boost the SN luminosity via shock interaction.

The star formation history of a galaxy is modulated by a plethora of internal processes and environmental conditions. The details of how these evolve and couple together is not fully understood yet. In this work, we study the effects that galaxy mergers and morphological transformations have on setting different modes of star formation at galactic scales and across cosmic time. We monitor the global properties of VINTERGATAN, a 20 pc resolution cosmological zoom-in simulation of a Milky Way-type galaxy. Between redshifts 1 and 5, we find that major mergers trigger multiple starburst episodes, corresponding to a tenfold drop of the gas depletion time down to 100 Myr. Bursty star formation is enabled by the emergence of a galactic disc, when the rotational velocity of gas starts to dominate over its velocity dispersion. Coherent motions of gas then outweigh disordered ones, such that the galaxy responds to merger-induced forcings by redistributing large amounts of gas towards high densities. As a result, the overall star formation rate is enhanced with an associated decrease in the depletion time. Before redshift 5, mergers are expected to be even more frequent. However, a more turbulent interstellar medium, is incapable of reacting in such a collective manner so as to spark rapid star formation. Thus, a constant long depletion time of 1 Gyr is kept, along with a low, but gradually increasing star formation rate. After the last major merger at redshift 1, VINTERGATAN spends the next 8 Gyr evolving secularly. It has a settled and adiabatically growing disc, and a constant star formation rate with gas depletion times of 1-2 Gyr. Our results are compatible with the observed rapid transition between different modes of star formation when galaxies leave the main sequence.

Collisionless, magnetized turbulence offers a promising framework for the generation of non-thermal high-energy particles in various astrophysical sites. Yet, the detailed mechanism that governs particle acceleration has remained subject to debate. By means of 2D and 3D PIC, as well as 3D (incompressible) magnetohydrodynamic (MHD) simulations, we test here a recent model of non-resonant particle acceleration in strongly magnetized turbulence~\cite{2021PhRvD.104f3020L}, which ascribes the energization of particles to their continuous interaction with the random velocity flow of the turbulence, in the spirit of the original Fermi model. To do so, we compare, for a large number of particles that were tracked in the simulations, the predicted and the observed histories of particles momenta. The predicted history is that derived from the model, after extracting from the simulations, at each point along the particle trajectory, the three force terms that control acceleration: the acceleration of the field line velocity projected along the field line direction, its shear projected along the same direction, and its transverse compressive part. Overall, we find a clear correlation between the model predictions and the numerical experiments, indicating that this non-resonant model can successfully account for the bulk of particle energization through Fermi-type processes in strongly magnetized turbulence. We also observe that the parallel shear contribution tends to dominate the physics of energization in the PIC simulations, while in the MHD incompressible simulation, both the parallel shear and the transverse compressive term provide about equal contributions.

We study the distributions of the baryons in massive halos ($M_{vir} > 10^{13} \ h^{-1}M_{\odot}$) in the $Magneticum$ suite of Smoothed Particle Hydrodynamical cosmological simulations, out to the unprecedented radial extent of $10 R_{500,\mathrm c}$. We confirm that, under the action of non-gravitational physical phenomena, the baryon mass fraction is lower in the inner regions ($<R_{500,\mathrm c}$) of increasingly less massive halos, and rises moving outwards, with values that spans from 51% (87%) in the regions around $R_{500,\mathrm c}$ to 95% (100%) at $10R_{500,\mathrm c}$ of the cosmological value in the systems with the lowest (highest; $M_{vir} \sim 5 \times 10^{14} \ h^{-1}M_{\odot}$) masses. The galaxy groups almost match the gas (and baryon) fraction measured in the most massive halos only at very large radii ($r>6 R_{500,\mathrm c}$), where the baryon depletion factor $Y_{\rm bar} = f_{\rm bar} / (\Omega_{\rm b}/\Omega_{\rm m})$ approaches the value of unity, expected for "closed-box" systems. We find that both the radial and mass dependency of the baryon, gas, and hot depletion factors are predictable and follow a simple functional form. The star mass fraction is higher in less massive systems, decreases systematically with increasing radii, and reaches a constant value of $Y_{\rm star} \approx 0.09$, where also the gas metallicity is constant, regardless of the host halo mass, as a result of the early ($z>2$) enrichment process.

Young planets provide a window into the early stages and evolution of planetary systems. Ideal planets for such research are in coeval associations, where the parent population can precisely determine their ages. We describe a young association (MELANGE-3) in the Kepler field, which harbors two transiting planetary systems (Kepler-1928 and Kepler-970). We identify MELANGE-3 by searching for kinematic and spatial overdensities around Kepler planet hosts with high levels of lithium. To determine the age and membership of MELANGE-3, we combine new high-resolution spectra with archival light curves, velocities, and astrometry of stars near Kepler-1928 spatially and kinematically. We use the resulting rotation sequence, lithium levels, and color-magnitude diagram of candidate members to confirm the presence of a coeval $105\pm$10 Myr population. MELANGE-3 may be part of the recently identified Theia 316 stream. For the two exoplanet systems, we revise the stellar and planetary parameters, taking into account the newly-determined age. Fitting the 4.5 yr Kepler light curves, we find that Kepler-1928 b is a $2.0\pm0.1R_\oplus$ planet on a 19.58-day orbit, while Kepler-970 b is a $2.8\pm0.2R_\oplus$ planet on a 16.73-day orbit. Kepler-1928 was previously flagged as an eclipsing binary, which we rule out using radial velocities from APOGEE and statistically validate the signal as planetary in origin. Given its overlap with the Kepler field, MELANGE-3 is valuable for studies of spot evolution on year timescales, and both planets contribute to the growing work on transiting planets in young stellar associations.

Using reconstructed initial conditions in the SDSS survey volume, we carry out constrained hydrodynamic simulations in three regions representing different types of the cosmic web: the Coma cluster of galaxies; the SDSS great wall; and a large low-density region at z ~ 0.05. These simulations are used to investigate the properties and evolution of intergalactic and intra-cluster media. About half of the warm-hot intergalactic gas is associated with filaments in the local cosmic web. Gas in the outskirts of massive filaments and halos can be heated significantly by accretion shocks generated by mergers of filaments and halos, respectively, and there is a tight correlation between gas temperature and the strength of the local tidal field. The simulations also predict some discontinuities associated with shock fronts and contact edges, which can be tested using observations of the thermal SZ effect and X-rays. A large fraction of the sky is covered by Ly$\alpha$ and OVI absorption systems, and most of the OVI systems and low-column density HI systems are associated with filaments in the cosmic web. The constrained simulations, which follow the formation and heating history of the observed cosmic web, provide an important avenue to interpret observational data. With full information about the origin and location of the cosmic gas to be observed, such simulations can also be used to develop observational strategies.

Recent studies on the planet-dominated regime of Type II migration showed that, contrary to the conventional wisdom, massive planets can migrate outwards. Using `fixed-planet' simulations these studies found a correlation between the sign of the torques acting on the planet and the parameter $K'$ (which describes the depth of the gap carved by the planet in the disc). We perform `live-planet' simulations exploring a range of $K'$ and disc mass values to test and extend these results. The excitation of planet eccentricity in live-planet simulations breaks the direct dependence of migration rate (rate of change of semi-major axis) on the torques imposed, an effect that `fixed-planet' simulations cannot treat. By disentangling the contribution to the torque due to the semi-major axis evolution from that due to the eccentricity evolution, we recover the relation between the magnitude and sign of migration and $K'$ and argue that this relation may be better expressed in terms of the related gap depth parameter $K$. We present a toy model in which the sign of planetary migration changes at a limiting value of $K$, through which we explore planets' migration in viscously evolving discs. The existence of the torque reversal shapes the planetary system's architecture by accumulating planets either at the stalling radius or in a band around it (defined by the interplay between the planet migration and the disc evolution). In either case, planets pile up in the area $1-10$ au, disfavouring hot Jupiter formation through Type II migration in the planet-dominated regime.

We report the results of a 2019-2021 monitoring campaign with Swift and associated target-of-opportunity observations with XMM-Newton and NuSTAR, examining the spectral and timing behavior of the highly variable ultraluminous X-ray source (ULX) NGC 925 ULX-3. We find that the source exhibits a 127-128 day periodicity, with fluxes typically ranging from 1e-13 to 8e-13 ergs/s/cm2. We do not find strong evidence for a change in period over the time that NGC 925 ULX-3 has been observed, although the source may have been in a much lower flux state when first observed with Chandra in 2005. We do not detect pulsations, and we place an upper limit on the pulsed fraction of ~40% in the XMM-Newton band, consistent with some previous pulsation detections at low energies in other ULXs. The source exhibits a typical ULX spectrum that turns over in the NuSTAR band and can be fitted using two thermal components. These components have a high temperature ratio that may indicate the lack of extreme inner disk truncation by a magnetar-level magnetic field. We examine the implications for a number of different models for superorbital periods in ULXs, finding that a neutron star with a magnetic field of ~10^12 G may be plausible for this source. The future detection of pulsations from this source would allow for the further testing and constraining of such models.

The growth of supermassive black holes, especially the associated state of active galactic nuclei (AGNs), is generally believed to be the key step in regulating star formation in massive galaxies. As the fuel of star formation, the cold gas reservoir is a direct probe of the effect of AGN feedback on their host galaxies. However, in observation, no clear connection has been found between AGN activity and the cold gas mass. In this paper, we find observational signals of significant depletion of the total neutral hydrogen gas reservoir in optically-selected type-2 AGN host central galaxies of stellar mass $10^{9}$--$10^{10}M_\odot$. The effect of AGN feedback on the cold gas reservoir is stronger for higher star formation rates and higher AGN luminosity. But it becomes much weaker above this mass range, consistent with previous findings focusing on massive galaxies. Our result suggests that low-mass and gas-rich AGN host central galaxies would first form dense cores before AGN feedback is triggered, removing their neutral hydrogen gas. More massive central galaxies may undergo a significantly different formation scenario by gradually building up dense cores with less effective and recurrent AGN feedback.

We present Suzaku observations of the Abell 98 (A98) triple galaxy cluster system and the purported intercluster filament. The three subclusters are expected to lie along a large scale cosmic filament. With partial azimuthal coverage of the northernmost cluster, we find that the inferred entropy profile of this relatively low mass cluster ($kT \approx 2.8$ keV) adheres to expectations from models of self-similar pure gravitational collapse in the region of the virial radius. There is evidence of extended structure beyond $r_{200}$ to the north of the northernmost cluster, along the merger axis, with properties consistent with what is expected for the warm-hot intergalacitc medium (WHIM; $kT = 0.11_{-0.02}^{+0.01}$ keV, $n_e = {7.6 \times 10^{-5}}^{+3.6 \times 10^{-5}}_{-3.6 \times 10^{-5}}$~cm$^{-3}$). No such emission is detected at the same radius in regions away from the merger axis, consistent with the expectation that the merger axis of this triple system lies along a large scale cosmic filament. In the bridge region between A98N and A98S, there is evidence of filamentary emission at the $2.2\sigma$ level, as well as a tentative detection of cool gas ($kT \sim 1$ keV). The entropy profile of this intercluster filament suggests that the A98 system is most likely aligned closer to the plane of the sky rather than along the line of sight. The structure to the north of the system, as well as in between A98N and A98S is indicative that the clusters are connected to a larger-scale structure spanning at least 4 Mpc.

We make the case that there can be no low-redshift solution to the $H_0$ tension. To robustly answer this question, we use a very flexible parameterization for the dark energy equation of state such that every cosmological distance still allowed by data exists within this prior volume. To then answer whether there exists a satisfactory solution to the $H_0$ tension within this comprehensive parameterization, we constrained the parametric form using different partitions of the Planck cosmic microwave background, SDSS-IV/eBOSS DR16 baryon acoustic oscillation, and Pantheon supernova datasets. When constrained by just the cosmic microwave background dataset, there exists a set of equations of state which yields high $H_0$ values, but these equations of state are ruled out by the combination of the supernova and baryon acoustic oscillation datasets. In other words, the constraint from the cosmic microwave background, baryon acoustic oscillation, and supernova datasets together does not allow for high $H_0$ values and converges around an equation of state consistent with a cosmological constant. Thus, since this very flexible parameterization does not offer a solution to the $H_0$ tension, there can be no solution to the $H_0$ tension that adds physics at only low redshifts.

Neutrinos can rapidly change flavor in the inner dense regions of core-collapse supernovae and neutron star mergers due to the neutrino fast flavor instability. If the amount of flavor transformation is significant, the FFI could significantly affect how supernovae explode and how supernovae and mergers enrich the universe with heavy elements. Since many state of the art supernova and merger simulations rely on neutrino transport algorithms based on angular moments of the radiation field, there is incomplete information with which to determine if the distributions are unstable to the FFI. In this work we test the performance of several proposed moment-based instability tests in the literature. We perform time-independent general relativistic neutrino transport on a snapshot of a 3D neutron star merger simulation to generate reasonable neutrino distributions and check where each of these criteria correctly predict instability. In addition, we offer a new ``maximum entropy'' instability test that is somewhat more complex, but offers more detailed (though still approximate) estimates of ELN crossing width and depth. We find that this maximum entropy test and the resonant trajectory test are particularly accurate at predicting instability in this snapshot, though all tests predict instability where significant flavor transformation is most likely.

The period and the period derivative of a pulsar are critical magnitudes for defining the properties of the magnetospheric size and plasma dynamics. The pulsar light cylinder, the magnetic field intensity nearby it, and the curvature radius all depend on these timing properties, and shape the observed high-energy synchro-curvature emission. Therefore, the radiative properties of pulsars are inextricably linked to them. This fact poses the question of how well does a given pulsar's spectral energy distribution embeds information of the timing parameters, and if so, whether we can deduce them if they have not been measured directly. This is relevant to possibly constrain the timing properties of potential pulsar candidates among unidentified $\gamma$-ray sources. We consider well-measured pulsar spectra blinding us from the knowledge of their timing properties, and address this question by using our radiative synchro-curvature model that was proven able to fit the observed spectra of the pulsar population. We find that in the majority of the cases studied (8/13), the spin period is constrained within a range of about one order of magnitude, within which the real period lies. In the other cases, there is degeneracy and no period range can be constrained. This can be used to facilitate the blind search of pulsed signals.

We have developed a chemo-dynamical approach to assign 36,010 metal-poor SkyMapper stars to various Galactic stellar populations. Using two independent techniques (velocity and action space behavior), $Gaia$ EDR3 astrometry, and photometric metallicities, we selected stars with the characteristics of the "metal-weak" thick disk population by minimizing contamination by the canonical thick disk or other Galactic structures. This sample comprises 7,127 stars, spans a metallicity range of $-3.50<${\metal}~$<-0.8$, and has a systematic rotational velocity of $\langle V_\phi\rangle=154$\,km\,s$^{-1}$ that lags that of the thick disk. Orbital eccentricities have intermediate values between typical thick disk and halo values. The scale length is $h_{R}=2.48^{+0.05}_{-0.05}$\,kpc and the scale height is $h_{Z}=1.68^{+0.19}_{-0.15}$\,kpc. The metallicity distribution function is well fit by an exponential with a slope of $\Delta\log{\rm N}/\Delta\metal=1.13\pm0.06$. Overall, we find a significant metal-poor component consisting of 261 SkyMapper stars with \metal$<-2.0$. While our sample contains only eleven stars with {\metal}~$\lesssim-3.0$, investigating the JINAbase compilation of metal-poor stars reveals another 18 such stars (five have {\metal}$<-4.0$) that kinematically belong to our sample. These distinct spatial, kinematic and chemical characteristics strongly suggest this metal-poor, phase-mixed kinematic sample to represent an independent disk component with an accretion origin in which a massive dwarf galaxy radially plunged into the early Galactic disk. Going forward, we propose to call the metal-weak thick disk population as the Atari disk, given its likely accretion origin, and in reference to it sharing space with the Galactic thin and thick disks.

The polar regions of Jupiter host a myriad of dynamically interesting phenomena including vortex configurations, folded-filamentary regions (FFRs), and chaotic flows. Juno observations have provided unprecedented views of the high latitudes, allowing for more constraints to be placed upon the troposphere and the overall atmospheric energy cycle. Moist convective events are believed to be the primary drivers of energetic storm behavior as observed on the planet. Here, we introduce a novel single layer shallow water model to investigate the effects of polar moist convective events at high resolution, the presence of dynamical instabilities over long timescales, and the emergence of FFRs at high latitudes. We use a flexible, highly parallelizable, finite-difference hydrodynamic code to explore the parameter space set up by previous models. We study the long term effects of deformation length (Ld), injected pulse size, and injected geopotential. We find that models with Ld beyond 1500 km (planetary Burger number, Bu$=4.4\times10^{-4}$) tend to homogenize their potential vorticity (PV) in the form of dominant stable polar cyclones, while lower Ld cases tend to show less stability with regards to Arnol'd-type flows. We also find that large turbulent forcing scales consistently lead to the formation of high latitude FFRs. Our findings support the idea that moist convection, occurring at high latitudes, may be sufficient to produce the dynamical variety seen at the Jovian poles. Additionally, derived values of localized horizontal shear and Ld may constrain FFR formation and evolution.

This paper introduces a new Planck Catalog of Polarized and Variable Compact Sources (PCCS-PV) comprising 153 sources, the majority of which are extragalactic. The data include both the total flux density and linear polarization measured by Planck with frequency coverage from 30 to 353 GHz, and temporal spacing ranging from days to years. We classify most sources as beamed, extragalactic radio sources; the catalog also includes several radio galaxies, Seyfert galaxies, and Galactic and Magellanic Cloud sources, including H IIi regions and planetary nebulae. An advanced extraction method applied directly to the multifrequency Planck time-ordered data, rather than the mission sky maps, was developed to allow an assessment of the variability of polarized sources. Our analysis of the time-ordered data from the Planck mission, tod2flux, allowed us to catalog the time-varying emission and polarization properties for these sources at the full range of polarized frequencies employed by Planck, 30 to 353 GHz. PCCS-PV provides the time- and frequency-dependent, polarized flux densities for all 153 sources. To illustrate some potential applications of the PCCS- PV, we conducted preliminary comparisons of our measurements of selected sources with published data from other astronomical instruments. In summary, we find general agreement between the Planck and the Institut de Radioastronomie Millim\'etrique (IRAM) polarization measurements as well as with the Mets\"ahovi 37 GHz values at closely similar epochs. These combined measurements also show the value of PCCS-PV results and the PCCS2 catalog for filling in missing spectral (or temporal) coverage and helping to define the spectral energy distributions of extragalactic sources. In turn, these results provide useful clues as to the physical properties of the sources.

We investigate the presence of hub-filament systems in a large sample of 146 active proto-clusters, using H$^{13}$CO$^{+}$ J=1-0 molecular line data obtained from the ATOMS survey. We find that filaments are ubiquitous in proto-clusters, and hub-filament systems are very common from dense core scales ($\sim$0.1 pc) to clump/cloud scales ($\sim$1-10 pc). The proportion of proto-clusters containing hub-filament systems decreases with increasing dust temperature ($T_d$) and luminosity-to-mass ratios ($L/M$) of clumps, indicating that stellar feedback from H{\sc ii} regions gradually destroys the hub-filament systems as proto-clusters evolve. Clear velocity gradients are seen along the longest filaments with a mean velocity gradient of 8.71 km s$^{-1}$pc$^{-1}$ and a median velocity gradient of 5.54 km s$^{-1}$pc$^{-1}$. We find that velocity gradients are small for filament lengths larger than $\sim$1~pc, probably hinting at the existence of inertial inflows, although we cannot determine whether the latter are driven by large-scale turbulence or large-scale gravitational contraction. In contrast, velocity gradients below $\sim$1~pc dramatically increase as filament lengths decrease, indicating that the gravity of the hubs or cores starts to dominate gas infall at small scales. We suggest that self-similar hub-filament systems and filamentary accretion at all scales may play a key role in high-mass star formation.

This paper shows that gravitating bodies travelling through the Galaxy can trap lighter interstellar particles that pass nearby with small relative velocities onto temporarily-bound orbits. The capture mechanism is driven by the Galactic tidal field, which can decelerate infalling objects to a degree where their binding energy becomes negative. Over time, trapped particles build a local overdensity -- a `halo'-- that reaches a steady state as the number of particles being captured equals that being tidally stripped. This paper uses classical stochastic techniques to calculate the capture rate and the phase-space distribution of particles trapped by a point-mass ($m_\star$). In a steady state, bound particles generate a local density enhancement $\delta(r)\sim r^{-3/2}$ (a.k.a `density spike') and follow a velocity dispersion profile $\sigma_h(r)\sim r^{-1/2}$. Collisionless $N$-body experiments show excellent agreement with these theoretical predictions within a distance range $r_0\lesssim r\lesssim r_t$, where $r_0=2Gm_\star/\sigma^2$ is the critical radius of field particles moving with a velocity dispersion $\sigma$, and $r_t$ is the tidal radius of the point-mass. Preliminary estimates that ignore collisions with planets and/or Galactic substructures suggest that the solar system may be surrounded by a halo that contains the order of $N^{\rm ISO}(<0.1 {\rm pc})\sim 10^7$ energetically-bound 'Oumuamua-like objects, and a dark matter mass of $M^{\rm DM}(<0.1 {\rm pc})\sim 10^{-13}M_\odot$. The presence of trapped interstellar matter in the solar system can affect current estimates on the size of the Oort Cloud, and leave a distinct signal in direct dark matter detection experiments.

The rotation rates of main-sequence stars slow over time as they gradually lose angular momentum to their magnetized stellar winds. The rate of angular momentum loss depends on the strength and morphology of the magnetic field, the mass-loss rate, and the stellar rotation period, mass, and radius. Previous observations suggested a shift in magnetic morphology between two F-type stars with similar rotation rates but very different ages (88 Leo and rho CrB). In this Letter, we identify a comparable transition in an evolutionary sequence of solar analogs with ages between 2-7 Gyr. We present new spectropolarimetry of 18 Sco and 16 Cyg A & B from the Large Binocular Telescope, and we reanalyze previously published Zeeman Doppler images of HD 76151 and 18 Sco, providing additional constraints on the nature and timing of this transition. We combine archival X-ray observations with updated distances from Gaia to estimate mass-loss rates, and we adopt precise stellar properties from asteroseismology and other sources. We then calculate the wind braking torque for each star in the evolutionary sequence, demonstrating that the rate of angular momentum loss drops by more than an order of magnitude between the ages of HD 76151 and 18 Sco (2.6-3.7 Gyr) and continues to decrease modestly to the age of 16 Cyg A & B (7 Gyr). We suggest that this magnetic transition may represent a disruption of the global dynamo arising from weaker differential rotation, and we outline plans to probe this phenomenon in additional stars spanning a wide range of spectral types.

Abell 1689 is a well studied cluster of galaxies and one of the largest gravitational lens systems ever observed. We have obtained a reconstruction of the cluster Abell 1689 using GRALE, a free-form lens inversion method that relies exclusively on the multiple image data. Non-inclusion of any data related to cluster member galaxies ensures an unbiased measure of the mass distribution, which is the most notable feature of this method. We used two different sets of multiply lensed systems from the available strong lensing data - one containing only the secure systems (107 images), and the other containing all available systems, only excluding some very non-secure systems (151 images). Both the reconstructions produced similar mass distributions whose circularly symmetric radial profiles are well fit with the Navarro-Frenk-White (NFW) profile with concentration parameter values, $c \sim 6.8$. For the very well-constrained central $\sim$100 kpc region of the cluster we made detailed comparison of the GRALE reconstructed lensing mass and stellar mass retrieved by the Spectral Energy Distribution (SED) fitting software FAST++. We found an offset in the light peak of the Brightest Cluster Galaxy (BCG) and its associated lensing mass peak, of about 10 kpc. We also found a light-unaccompanied mass peak in this region, whose location agrees with features retrieved by some of the earlier reconstructions using different methodologies. Both the light-unaccompanied mass peak and the BCG offset are consistent with dark matter self-interaction cross-section $\sigma \lesssim 1$cm$^2$/g, while the mass peak is in tension with larger cross-sections.

We use the small scales of the Dark Energy Survey (DES) Year-3 cosmic shear measurements, which are excluded from the DES Year-3 cosmological analysis, to constrain the baryonic feedback. To model the baryonic feedback, we adopt a baryonic correction model and use the numerical package \texttt{Baccoemu} to accelerate the evaluation of the baryonic nonlinear matter power spectrum. We design our analysis pipeline to focus on the constraints of the baryonic suppression effects, utilizing the implication given by a principal component analysis on the Fisher forecasts. Our constraint on the baryonic effects can then be used to better model and ameliorate the effects of baryons in producing cosmological constraints from the next generation large-scale structure surveys. We detect the baryonic suppression on the cosmic shear measurements with a $\sim 2 \sigma$ significance. The characteristic halo mass for which half of the gas is ejected by baryonic feedback is constrained to be $M_c > 10^{13.2} h^{-1} M_{\odot}$ (95\% C.L.). The best-fit baryonic suppression is $\sim 5\%$ at $k=1.0 {\rm Mpc}\ h^{-1}$ and $\sim 15\%$ at $k=5.0 {\rm Mpc} \ h^{-1}$. Our findings are robust with respect to the assumptions about the cosmological parameters, specifics of the baryonic model, and intrinsic alignments.

We present new light curves for the four bright images of the five image cluster-lensed quasar gravitational lens system SDSS J1004+4112. The light curves span 14.5 years and allow measurement of the time delay between the trailing bright quasar image D and the leading image C. When we fit all four light curves simultaneously and combine the models using the Bayes Information Criterion (BIC), we find a time delay of $\Delta t_{DC}= 2458.47 \pm 1.02$ days (6.73 years), the longest ever measured for a gravitational lens. For the other two independent time delays we obtain $\Delta t_{BC}=782.20 \pm 0.43$ days (2.14 years) and $\Delta t_{AC}= 825.23 \pm 0.46$ days (2.26 years), in agreement with previous results. The information criterion is needed to weight the results for light curve models with different polynomial orders for the intrinsic variability and the effects of differential microlensing. The results using the Akaike Information Criterion (AIC) are slightly different, but, in practice, the absolute delay errors are all dominated by the $\sim 4\%$ cosmic variance in the delays rather than the statistical or systematic measurement uncertainties. Despite the lens being a cluster, the quasar images show slow differential variability due to microlensing at the level of a few tenths of a magnitude.

Recent observations of quasars show high line-flux ratios in their broad emission lines and the ratios appear to be independent of redshift up to $z \gtrsim 6$, which indicate that the broad-line regions of these early quasars are surprisingly metal-rich. Here, we revisit the chemical evolution of high-redshift quasars by adding a new ingredient, i.e., the neutrino-dominated accretion flows (NDAFs) with outflows, on top of the conventional core-collapse supernovae (CCSNe). In the presence of the chemical contribution from NDAFs with outflows, the total metal mass (i.e., the summation of the conventional CCSN and NDAFs with outflows) per CCSN depends weakly upon the mass of the progenitor star if the mass is in the range of $\sim 25-55~M_{\odot}$. We model the chemical evolution by adopting a improved open-box model with three typical initial mass functions (IMFs). We find that, with the additional chemical contribution from NDAFs with outflows, the quasar metallicity can be enriched more rapidly in the very early Universe ($z \sim 10$) and reaches higher saturation than the no-NDAF case at $z \sim 8$, after which they evolve slowly with redshift. The quasar metallicity can reach $\sim 20~Z_{\odot}$ ($Z_\odot$ denotes the metallicity of the Sun; and $\sim 20\%$ of which is produced by NDAF outflows) at $z \sim 8$ for the ``top-heavy'' IMF model in \citet{Toyouchi2022}, which readily explains the quasar observations on the super-solar metal abundance and redshift-independent evolution.

We present the broadband (0.3-40.0 keV) X-ray analysis of intermediate polar Paloma using simultaneous data from XMM-Newton and NuSTAR observatories. The X-ray power spectra show strong modulations over orbital period compared to spin period. The orbit folded lightcurves show single broad hump like structure with strong dips for soft to medium X-rays (0.3-10.0 keV). We propose that at least one pole is visible over the orbital cycle. The dips arise due to complex intrinsic absorber, strong enough to have effect well around 15 keV. This absorber is presumably contributed from accretion curtain or stream, including the pre-shock flow. We notice significant variation of this absorber with orbital phase, with maximum absorption during orbital phase 0.1-0.22. The absorber requires more than one partial covering absorber component, specifying the necessity to use distribution of column densities for spectral modelling of the source. Isobaric cooling flow component is utilized to model the emission from the multi-temperature post-shock region, giving shock temperature of $31.7_{-3.5}^{+3.3}$keV, which corresponds to white dwarf mass of $0.74_{-0.05}^{+0.04}\;M_{\odot}$. We have used both the neutral absorber and the warm absorber models, which statistically give similarly good fit, but with different physical implications. Among the Fe K$_{\alpha}$ line complex, the neutral line is the weakest. We probed the Compton reflection, and found minimal statistical contribution in the spectral fitting, suggesting presence of weak reflection in Paloma.

The detection of photons with energies greater than a few tenths of an MeV, interacting via Compton scattering and/or pair production, faces a number of difficulties. The reconstruction of single-scatter Compton events can only determine the direction of the incoming photon to a cone, or an arc thereof and the angular resolution of pair-conversion telescopes is badly degraded at low energies. Both of these difficulties are partially overcome if the density of the interaction medium is low. Also no precise polarization measurement on a cosmic source has been obtained in that energy range to date. We present the potential of low-density high-precision homogeneous active targets, such as time-projection chambers (TPC) to provide an unambiguous photon direction measurement for Compton events, an angular resolution down to the kinematic limit for pair events, and the polarimetry of linearly polarized radiation.

Upcoming spectroscopic redshift surveys use emission line galaxies (ELGs) to trace the three-dimensional matter distributions with wider area coverage in the deeper Universe. Since the halos hosting ELGs are young and undergo infall towards more massive halos along filamentary structures, contrary to a widely employed luminous red galaxy sample, the dynamics specific to ELGs should be taken into account to refine the theoretical modelling at non-linear scales. In this paper, we scrutinise the halo occupation distribution (HOD) and clustering properties of ELGs by utilising IllustrisTNG galaxy formation hydrodynamical simulations. Leveraging stellar population synthesis technique coupled with the photo-ionization model, we compute line intensities of simulated galaxies and construct mock H$\alpha$ and [OII] ELG catalogues. The line luminosity functions and the relation between the star formation rate and line intensity are well consistent with observational estimates. Next, we measure the HOD and demonstrate that there is a distinct population for the central HOD, which corresponds to low-mass infalling halos. We then perform the statistical inference of HOD parameters from the projected correlation function. Our analysis indicates that the inferred HODs significantly deviate from the HOD measured directly from simulations although the best-fit model yields a good fit to the projected correlation function. It implies that the information content of the projected correlation function is not adequate to constrain HOD models correctly and thus, it is important to employ mock ELG catalogues to calibrate the functional form of HOD models and add prior information on HOD parameters to robustly determine the HOD.

The distribution of magnetic fields of positive and negative polarities over the surface of the Sun was studied. Synoptic maps of the photospheric magnetic field (NSO Kitt Peak, 1978--2016) were used for the analysis. In the time-latitude diagram for weak magnetic fields ($B \leq 5 G$), inclined bands are clearly visible, indicating the alternating dominance of magnetic fields with positive or negative polarity drifting towards the poles of the Sun. Analysis of the time-latitude diagram using the method of empirical orthogonal functions (EOF) made it possible to establish a cyclic change in the polarity of magnetic field flows with a period of 1-3 years, which indicates a possible connection with quasi biennial variation. Similar period values are obtained by averaging over the latitude of the time-latitude diagram

The characterisation of detached eclipsing binaries with low mass components has become important when verifying the role of convection in stellar evolutionary models, which requires model-independent measurements of stellar parameters with great precision. However, spectroscopic characterisation depends on single-target radial velocity observations and only a few tens of well-studied low-mass systems have been diagnosed in this way. We characterise eclipsing detached systems from the {\it Kepler} field with low mass components by adopting a purely-photometric method. Based on an extensive multi-colour dataset, we derive effective temperatures and photometric masses of individual components using clustering techniques. We also estimate the stellar radii from additional modelling of the available {\it Kepler} light curves. Our measurements confirm the presence of an inflation trend in the mass-radius diagram against theoretical stellar models in the low-mass regime.

gamma Cas is known for its hard and intense X-ray emission that could trace accretion by a compact companion, wind interaction with a hot sub-dwarf companion, or magnetic interaction between the star and its Be decretion disc. These scenarios should lead to diverse dependences of the hard X-ray emission on disc density. We collected X-ray observations of gamma Cas during an episode of enhanced disc activity around January 2021. We investigate the variations in the disc properties using time series of dedicated optical spectroscopy and existing broadband photometry. Epoch-dependent Doppler maps of the H-alpha, H-beta, and He I 5876 emission lines are built to characterise the emission regions in velocity space. We analyse 4 XMM-Newton observations taken at key phases of the enhanced disc activity episode. Archival data are used to study the long-term correlation between optical and X-ray emission. Optical spectroscopy unveils an increase in the radial extent of the emission regions during the episode of enhanced disc activity, whilst no increase in the V-band flux is recorded. Doppler maps do not reveal any stable feature in the disc resulting from the putative action of the companion on the outer parts of the Be disc. No increase in the hard emission is observed in relation to the enhanced disc activity. However, at two occasions, the soft X-ray emission of gamma Cas is strongly attenuated, suggesting more efficient obscuration by a large flaring Be disc. There is a strong correlation between the long-term variations in the X-ray flux and in the V-band photometry. The observed behaviour of gamma Cas suggests no direct link between the properties of the outer regions of the Be disc and the hard X-ray emission, but favours a link between the level of X-ray emission and the properties of the inner part of the Be disc. These results thus disfavour an accretion or colliding wind scenario.

Realistic lightcone mocks are important in the clustering analyses of large galaxy surveys. For simulations where only the snapshots are available, it is common to create approximate lightcones by joining together the snapshots in spherical shells. We assess the two-point clustering measurements of central galaxies in approximate lightcones built from the Millennium-XXL simulation, which are constructed using different numbers of snapshots. The monopole and quadrupole of the real-space correlation function is strongly boosted on small scales below 1 Mpc/h, due to some galaxies being duplicated at the boundaries between snapshots in the lightcone. When more snapshots are used, the total number of duplicated galaxies is approximately constant, but they are pushed to smaller separations. The effect of this in redshift space is small, as long as the snapshots are cut into shells in real space. Randomly removing duplicated galaxies is able to reduce the excess clustering signal. Including satellite galaxies will reduce the impact of the duplicates, since many small-scale pairs come from satellites in the same halo. Galaxies that are missing from the lightcone at the boundaries can be added to the lightcone by having a small overlap between each shell. This effect will impact analyses that use very small-scale clustering measurements, and when using mocks to test the impact of fibre collisions.

The aim of this work is to study the impact of a binary companion on the evolution of two-planet systems during both the type-II migration phase and their long-term evolution after the dissipation of the protoplanetary disk. We use the symplectic integrator SyMBA, modified to include a wide binary companion. We also include the Type-II migration of giant planets during the disk phase with suitable eccentricity and inclination damping as well as the disk gravitational potential acting on the planets and the nodal precession of the disk induced by the binary companion. We consider various inclinations, eccentricities, and separations of the binary companion. Disk migration allows the formation of planet pairs in mean-motion resonances (MMR) despite the presence of the binary companion. When the binary separation is wide (1000au), the timescale of the perturbations it raises on the planets is longer than the disk's lifetime and resonant pairs are routinely formed in the 2:1, 5:2 and 3:1 MMR. Provided the planet-planet interaction timescale is smaller than the binary perturbations timescale, these systems can remain in resonance long after the disk has dissipated. When the binary separation is smaller (250au), only planets in the 2:1 resonance tend to remain in a resonant state and more chaotic evolutions are observed, as well as more ejections. After those ejections, the remaining planet can become eccentric due to the perturbations from the binary companion and for strongly inclined binary companions captures in the von Ziepel-Lidov-Kozai resonance can occur, while in systems with two planets this mechanism is quenched by planet-planet interactions. Our simulations reveal that the interplay between planet-disk, planet-planet and planet-binary interactions can lead to the formation of resonant pairs of planets which remain stable over timescales much longer than the disk's lifetime.

Many galaxies display clear bulges and discs, and understanding how these components form is a vital step towards understanding how the galaxy has evolved into what we see today. The BUDDI-MaNGA project aims to study galaxy evolution and morphological transformations through the star-formation histories of the bulges and discs. We have applied our BUDDI software to galaxies from the MaNGA Survey in the SDSS DR15 in order to isolate their bulge and disc spectra, from which we derived their stellar populations. To date, this work provides the largest sample of clean bulge and disc spectra extracted from IFU datacubes using the galaxies light profile information, and will form the basis for a series of papers aiming to answer open questions on how galaxies have formed and evolved, and the role of their individual structures. This paper presents an introduction to the project, including an overview of these fits, a characterisation of the sample, and a series of tests on the fits to ensure reliability.

Many processes have been proposed to explain the quenching of star formation in spiral galaxies and their transformation into S0s. These processes affect the bulge and disc in different ways, and so by isolating the bulge and disc spectra, we can look for these characteristic signatures. In this work, we used BUDDI to cleanly extract the spectra of the bulges and discs of 78 S0 galaxies in the MaNGA Survey. We compared the luminosity and mass weighted stellar populations of the bulges and discs, finding that bulges are generally older and more metal rich than their discs. When considering the mass and environment of each galaxy, we found that the galaxy stellar mass plays a more significant role on the formation of the bulges. Bulges in galaxies with masses $\geq10^{10}M_\odot$ built up the majority of their mass rapidly early in their lifetimes, while those in lower mass galaxies formed over more extended timescales and more recently. No clear difference was found in the formation or quenching processes of the discs as a function of galaxy environment. We conclude that more massive S0 galaxies formed through an inside-out scenario, where the bulge formed first and evolved passively while the disc underwent a more extended period of star formation. In lower mass S0s, the bulges and discs either formed together from the same material, or through an outside-in scenario. Our results therefore imply multiple formation mechanisms for S0 galaxies, the pathway of which is chiefly determined by a galaxy's current stellar mass.

The circumgalactic medium (CGM) is the location where the interplay between large-scale outflows and accretion onto galaxies occurs. Metals in different ionization states flowing between the circumgalactic and intergalactic mediums are affected by large galactic outflows and low-ionization state inflowing gas. Observational studies on their spatial distribution and their relation with galaxy properties may provide important constraints on models of galaxy formation and evolution. To provide new insights into the spatial distribution of the circumgalactic of star-forming galaxies, we select a sample of 238 close pairs at $1.5 < z <4.5$ ($\langle z\rangle\sim$2.6) from the VIMOS Ultra Deep Survey. We then generate composite spectra by co-adding spectra of $background$ galaxies that provide different sight-lines across the CGM to examine the spatial distribution of the gas located around these galaxies and investigate possible correlations between the strength of the low- and high-ionization absorption features with different galaxy properties. We detect C II, Si II, Si IV and C IV) up to separations $\langle b \rangle=$ 172 kpc and 146 kpc. Our $W_{0}$ radial profiles suggest a potential redshift evolution for the CGM gas content producing these absorptions. We find a correlation between C II and C IV with star formation rate, stellar mass and trends with galaxy size estimated by the effective radius and azimuthal angle. Galaxies with high star formation rate show stronger C IV absorptions compared with star-forming galaxies with low SFR and low stellar mass. These results could be explained by stronger outflows, softer radiation fields unable to ionize high-ionization state lines or by the galactic fountain scenario where metal-rich gas ejected from previous star-formation episodes fall back to the galaxy.

In this work, we study the influence of $f(R,T)$ gravity on rapidly rotating neutron stars. First we discuss the main aspects of this modified theory of gravity where the gravitational Lagrangian is an arbitrary function of the Ricci scalar $R$ and of the trace of the energy-momentum tensor $T$. Then we present the basic equations for neutron stars including the equations of state used in the present work to describe the hadronic matter. Some physical quantities of interest are calculated such as mass-radius relations, moments of inertia, angular momentum, and compactness. By considering four different rotation regimes, we obtain results that indicate substantial modifications in the physical properties of neutron stars in $f(R,T)$ gravity when compared to those in the context of general relativity. In particular, the mass-radius relation for sequences of stars indicates that $f(R,T)$ gravity increases the mass and the equatorial radius of the neutron stars for stars rotating with an angular velocity smaller than Kepler limit.

Electromagnetic ion cyclotron waves are expected to often pitch-angle scatter and cause atmospheric precipitation of relativistic ($> 1$ MeV) electrons in Earth's radiation belts. However, it has been a longstanding mystery how relativistic electrons in the hundreds of keV range (but $<1$ MeV), which are not resonant with these waves, precipitate simultaneously with those $>1$ MeV. We demonstrate that, when the wave packets are short, nonresonant interactions enable such scattering of $100$s of keV electrons by introducing a spread in wavenumber space. We generalize the quasi-linear diffusion model to include nonresonant effects. The resultant model exhibits an exponential decay of the scattering rates extending below the minimum resonant energy depending on the shortness of the wave packets. This generalized model naturally explains observed nonresonant electron precipitation in the hundreds of keV concurrent with $>1$ MeV precipitation.

Magnetic reconnection is prevalent in magnetized plasmas in space and laboratories. Despite significant investigations on reconnection in electron-ion plasmas, studies of reconnection in magnetized plasmas with negatively charged dust grains are quite sparse. Here we report the first fully kinetic simulations of collisionless reconnection in a three-species (i.e., electron, proton, and negatively charged dust grain) dusty plasma, through which the discovery of double Hall pattern is made. The double Hall pattern consists of a traditional Hall quadruple current in between the ion and electron diffusion region, and a reversed Hall current in between the boundary of the ion and dust diffusion region. The analysis of the reconnection rate is also given. This study may be applicable to explain observations of planetary magnetospheres and the astrophysical objects, and may be realized in the laboratory studies of dusty plasmas.

Thanks to unparalleled near-horizon images of the shadows of Messier 87* (M87*) and Sagittarius A* (Sgr A*) delivered by the Event Horizon Telescope (EHT), they opened up to us two amazing windows for the strong-field test of the gravity theories as well as fundamental physics. Information recently published from EHT about the Sgr A*'s shadow conduct us to a novel probe of Lorentz symmetry violation (LSV) within Standard-Model Extension (SME) framework. Despite the agreement between the shadow image of Sgr A* and the prediction of the general theory of relativity, there is still a tiny space that is expected to fix by taking into account some of the fundamental corrections. We bring up the idea that the recent inferred shadow image of Sgr A* is explicable by a minimal SME-inspired Schwarzschild metric containing the Lorentz violating (LV) terms obtained from the post-Newtonian approximation. The LV terms embedded in Schwarzschild metric are dimensionless spatial coefficients ${\bar s}^{jk}$ associated with the field responsible for the LSV in the gravitational sector of minimal SME theory. In this way, one can control the Lorentz invariance violation in the allowed sensitivity level of the first shadow image of Sgr A*. Actually, using the bounds released within $1\sigma$ uncertainty for the shadow size of Sgr A* and whose fractional deviation from standard Schwarzschild, we set upper limits for the two different combinations of spatial diagonal coefficients of SME and time-time coefficient, as well. The best upper limit is at the $10^{-3}$ level, consistent with the value already extracted from Gravity Probe B for the combination of temporal and spatial coefficients of SME.

Inflation models based on scalar-tensor theories of gravity are formulated in the Jordan frame but most often analysed in the Einstein frame. The transformation between the frames is not always desirable. In this work we formulate slow-roll conditions in the Jordan frame. This is achieved by comparing different background quantities and approximations on the same spatial slice in both frames. We use these approximations to derive simple equations that can be applied to compute inflation model observables in terms of Jordan frame quantities only. Finally, we apply some of the results to analyse generalised induced gravity models and compare them with the latest observations.