Papers for Monday, Oct 03 2022

We present new radio and X-ray observations of two nearby ($< 4$ Mpc) low-mass early-type galaxies with dynamically-confirmed central black holes: NGC 5102 and NGC 205. NGC 5102 shows a weak nuclear X-ray source and has no core radio emission. However, for the first time we demonstrate that it shows luminous extended radio continuum emission in low-resolution, low-frequency ($< 3$ GHz) data, consistent with jet lobes on scales $\gtrsim 100$ pc formed from past accretion and jet activity. By contrast, in new, extremely deep, strictly-simultaneous Very Large Array and Chandra observations, no radio or X-ray emission is detected from the black hole in NGC 205. We consider these measurements and upper limits in the context of the few other low-mass early-type galaxies with dynamically-confirmed black holes, and show that the mean ratio of bolometric to Eddington luminosity in this sample is only $\textrm{log} \, (L_{\rm bol}/L_{\rm Edd}) = -6.57\pm0.50$. These Eddington ratios are lower than typical in a comparison sample of more massive early-type galaxies, though this conclusion is quite tentative due to our small sample of low-mass galaxies and potential biases in the comparison sample. This preliminary result is in mild tension with previous work using less sensitive observations of more distant galaxies, which predict higher X-ray luminosities than we observe for low-mass galaxies. If it is confirmed that central black holes in low-mass galaxies typically have low Eddington ratios, this presents a challenge to measuring the occupation fraction of central black holes with standard optical emission line, X-ray, or radio surveys.

The Large and Small Magellanic Clouds (LMC/SMC) are the closest major satellite galaxies of the Milky Way. They are likely on their first passage on an infalling orbit towards our Galaxy (Besla et al. 2007) and trace the ongoing dynamics of the Local Group (D'Onghia & Fox 2016). Recent measurements of a high mass for the LMC (M_halo = 10^(11.1-11.4) solar masses; Penarrubia et al. 2016, Erkal et al. 2018, 2019, Kallivayalil et al. 2018) imply the LMC should host a Magellanic Corona: a collisionally ionized, warm-hot gaseous halo at the virial temperature (10^(5.3-5.5) K) initially extending out to the virial radius (100-130 kpc). Such a Corona would have shaped the formation of the Magellanic Stream (Lucchini et al. 2020), a tidal gas structure extending over 200 degrees across the sky (D'Onghia & Fox 2016, Besla et al. 2012, Nidever et al. 2010) that is bringing in metal poor gas to the Milky Way (Fox et al. 2014). No observational evidence for such an extended Corona has been published previously, with detections of highly ionized gas only reported in directions directly toward the LMC, where winds from the LMC disk may dominate (deBoer & Savage 1980, Wakker et al. 1998). Here we show evidence for this Magellanic Corona with a potential direct detection in highly ionized oxygen (O^+5), and indirectly via triply-ionized carbon and silicon, seen in ultraviolet absorption toward background quasars. We find that the Magellanic Corona is part of a pervasive multiphase Magellanic circumgalactic medium (CGM) seen in many ionization states with a declining projected radial profile out to at least 35 kpc from the LMC and a total ionized CGM mass of log_10(M_HII;CGM/solar masses) = 9.1 +/- 0.2. The evidence for the Magellanic Corona is a crucial step forward in characterizing the Magellanic Group and its nested evolution with the Local Group.

We used Transiting Exoplanet Survey Satellite (TESS) data to identify 29 candidate active galactic nuclei (AGNs) through their optical variability. The high-cadence, high-precision TESS light curves present a unique opportunity for the identification of AGNs, including those not selected through other methods. Of the candidates, we found that 18 have either previously been identified as AGNs in the literature or could have been selected based on emission-line diagnostics, mid-IR colors, or X-ray luminosity. AGNs in low-mass galaxies offer a window into supermassive black hole (SMBH) and galaxy co-evolution and 8 of the 29 candidates have estimated black hole masses $\mathrm{\lesssim 10^{6} M_{\odot}}$. The low-mass galaxies NGC 4395 and NGC 4449 are two of our five "high-confidence" candidates. By applying our methodology to the entire TESS main and extended mission datasets, we expect to identify $\sim$45 more AGN candidates, of which $\sim$26 will be new and $\sim$8 will be in low-mass galaxies.

We study the link between galaxies and HI-selected absorption systems at z~3-4 in the MUSE Analysis of Gas around Galaxies (MAGG) survey, an ESO large programme consisting of integral field pectroscopic observations of 28 quasar fields hosting 61 strong absorbers with $\rm N_{\rm HI}\gtrsim 10^{16.5}~\rm cm^{-2}$. We identify 127 Ly$\alpha$ emitting galaxies (LAEs) around the absorbers, corresponding to a detection rate of 82$\pm$16 per cent. The luminosity function of these LAEs is approximately 5 times higher in normalization than the field population and we detect a significant clustering of galaxies with respect to the gas, confirming that high column density absorbers and LAEs trace each other. Between 30 and 40 per cent of the absorbers are associated with multiple LAEs, which lie preferentially along filaments. Galaxies in groups also exhibit a three times higher covering factor of optically-thick gas compared to isolated systems. No significant correlations are identified between the emission properties of LAEs and the absorption properties of optically-thick gas clouds, except for a weak preference of brighter and multiple galaxies to reside near broad absorbers. Based on the measured impact parameters and the covering factor, we conclude that the near totality of optically-thick gas in the Universe can be found in the outer circumgalactic medium (CGM) of LAEs or in the intergalactic medium (IGM) in proximity to these galaxies. Thus, LAEs act as tracers of larger scale structures within which both galaxies and optically-thick clouds are embedded. The patchy and inhomogeneous nature of the CGM and IGM explains the lack of correlations between absorption and emission properties. This implies that very large samples are needed to unveil the trends that encode the properties of the baryon cycle.

Andromeda (And) XXV has previously been reported as a dwarf spheroidal galaxy (dSph) with little-to-no dark matter. However, the uncertainties on this result were significant. In this study, we double the number of member stars and re-derive the kinematics and mass of And XXV. We find that And XXV has a systemic velocity of $\nu_\mathrm{r}=-107.7\pm1.0 \mathrm{~km s}^{-1}$ and a velocity dispersion of $\sigma_\nu=4.5\pm1.0\mathrm{~km s}^{-1}$. With this better constrained velocity dispersion, we derive a mass contained within the half-light radius of $M(r< r_\mathrm{h})=6.9^{+3.2}_{-2.8}\times10^6\mathrm{~M}_\odot$. This mass corresponds to a mass-to-light ratio of $\mathrm{[M/L]}_\mathrm{r_\mathrm{h}}=37^{+17}_{-15}\mathrm{~M}_\odot/\mathrm{L}_\odot$, demonstrating, for the first time, that And XXV has an unambiguous dark matter component. We also measure the metallicity of And XXV to be $\mathrm{[Fe/H]}=-1.9\pm0.1$$\mathrm{~}$dex, which is in agreement with previous results. Finally, we extend the analysis of And XXV to include mass modelling using GravSphere. We find that And XXV has a low central dark matter density, $\rho_\mathrm{DM}(150\mathrm{pc})= 2.7^{+1.8}_{-1.6}\times10^7\mathrm{~M}_\odot\mathrm{kpc}^{-3}$, making And XXV a clear outlier when compared to other Local Group (LG) dSphs of the similar stellar mass. In a companion paper, we will explore whether some combination of dark matter cusp-core transformations and/or tides can explain And XXV's low density.

Asteroseismic time-series data have imprints of stellar oscillation modes, whose detection and characterization through time-series analysis allows us to probe stellar interiors physics. Such analyses usually occur in the Fourier domain by computing the Lomb-Scargle (LS) periodogram, an estimator of the \textit{power spectrum} underlying unevenly-sampled time-series data. However, the LS periodogram suffers from the statistical problems of (1) inconsistency (or noise) and (2) bias due to high spectral leakage. In addition, it is designed to detect strictly periodic signals but is unsuitable for non-sinusoidal periodic or quasi-periodic signals. Here, we develop a multitaper spectral estimation method that tackles the inconsistency and bias problems of the LS periodogram. We combine this multitaper method with the Non-Uniform Fast Fourier Transform (\texttt{mtNUFFT}) to more precisely estimate the frequencies of asteroseismic signals that are non-sinusoidal periodic (e.g., exoplanet transits) or quasi-periodic (e.g., pressure modes). We illustrate this using a simulated and the Kepler-91 red giant light curve. Particularly, we detect the Kepler-91b exoplanet and precisely estimate its period, $6.246 \pm 0.002$ days, in the frequency domain using the multitaper F-test alone. We also integrate \texttt{mtNUFFT} into the \texttt{PBjam} package to obtain a Kepler-91 age estimate of $3.96 \pm 0.48$ Gyr. This $36$\% improvement in age precision relative to the $4.27 \pm 0.75$ Gyr APOKASC-2 (uncorrected) estimate illustrates that \texttt{mtNUFFT} has promising implications for Galactic archaeology, in addition to stellar interiors and exoplanet studies. Our frequency analysis method generally applies to time-domain astronomy and is implemented in the public Python package \texttt{tapify}, available at \url{https://github.com/aaryapatil/tapify}.

We investigate the cross-calibration of the Hinode/SOT-SP and SDO/HMI instrument meta-data, specifically the correspondence of the scaling and pointing information. Accurate calibration of these datasets gives the correspondence needed by inter-instrument studies and learning-based magnetogram systems, and is required for physically-meaningful photospheric magnetic field vectors. We approach the problem by robustly fitting geometric models on correspondences between images from each instrument's pipeline. This technique is common in computer vision, but several critical details are required when using scanning slit spectrograph data like Hinode/SOT-SP. We apply this technique to data spanning a decade of the Hinode mission. Our results suggest corrections to the published Level 2 Hinode/SOT-SP data. First, an analysis on approximately 2,700 scans suggests that the reported pixel size in Hinode/SOT-SP Level 2 data is incorrect by around 1%. Second, analysis of over 12,000 scans show that the pointing information is often incorrect by dozens of arcseconds with a strong bias. Regression of these corrections indicates that thermal effects have caused secular and cyclic drift in Hinode/SOT-SP pointing data over its mission. We offer two solutions. First, direct co-alignment with SDO/HMI data via our procedure can improve alignments for many Hinode/SOT-SP scans. Second, since the pointing errors are predictable, simple post-hoc corrections can substantially improve the pointing. We conclude by illustrating the impact of this updated calibration on derived physical data products needed for research and interpretation. Among other things, our results suggest that the pointing errors induce a hemispheric bias in estimates of radial current density.

While large scale primordial non-Gaussianity is strongly constrained by present-day data, there are no such constraints at Mpc scales. Here we investigate the effect of significant small-scale primordial non-Gaussianity on structure formation and the galaxy formation process with collisionless simulations: specifically, we explore four different types of non-Gaussianities. Generically, we find a distinct and potentially detectable feature in the matter power spectrum around the non-linear scale. We then show in particular that a negatively-skewed distribution of the potential random field, hence positively skewed in terms of overdensities, with $f_{\rm NL} \approx -1000$ at these scales, implies that typical galaxy-sized halos reach half of their present-day mass at an earlier stage and have a quieter merging history than in the Gaussian case. Their environment between 1 and 5 virial radii at $z=0$ is less dense than in the Gaussian case. This quieter history and less dense environment has potentially interesting consequences in terms of the formation of bulges and bars. Moreover, we show that subhalos have a more flattened distribution around their host than in the Gaussian case, albeit not as flattened as the 11 most massive Milky Way satellites, and that the two most massive subhalos tend to display an interesting anti-correlation of velocities around their host, indicative of kinematic coherence. All these hints will need to be statistically confirmed in larger-box simulations with scale-dependent non-Gaussian initial conditions, followed by hydrodynamical zoom-in simulations to explore the detailed consequences of small-scale non-Gaussianities on galaxy formation.

Radio-Loud (RL) Active Galactic Nuclei (AGNs) are among the brightest astrophysical sources at all wavelengths. Their relativistic jets can affect both their Supermassive Black Holes (SMBHs) growth and the surrounding intergalactic medium. While in the radio band these jets can be observed at all scales (from pc to Mpc scales), their X-ray and {\gamma}-ray emission is expected to be concentrated on very small scales (<10 pc). However, after the launch of the Chandra X-ray telescope, several kpc-scale jets were detected and the mechanism responsible for their high-energy radiation at these scales is still under debate. Understanding its origin is crucial also to derive the physical properties of these jets (e.g. the power) at large scales and, as a consequence, their impact on the environment. In the following, we explore the Inverse Compton interaction of the relativistic electrons within relativistic jets with the Cosmic Microwave background photons (IC/CMB) as possible interpretation. Moreover, we also estimate how this interpretation could also affect the observed evolution across cosmic times of the SMBHs hosted in jetted systems.

This paper discusses if large scale galaxy distribution samples containing almost one million objects can be characterized as fractal systems. The analysis performed by Teles et al. (2021; arXiv:2012.07164) on the UltraVISTA DR1 survey is extended here to the SPLASH and COSMOS2015 catalogs, hence adding 750k new galaxies with measured redshifts to the studied samples. The standard $\Lambda$CDM cosmology having $H_0=(70\pm5)$ km/s/Mpc and number density tools required for describing these galaxy distributions as single fractal systems with dimension $D$ are adopted. We use the luminosity distance $d_L$, redshift distance $d_z$ and galaxy area distance (transverse comoving distance) $d_G$ as relativistic distance definitions to derive galaxy number densities in the redshift interval $0.1\le z\le4$ at volume limited subsamples defined by absolute magnitudes in the K-band. Similar to the findings of Teles et al. (2021; arXiv:2012.07164), the results show two consecutive redshift scales where galaxy distribution data behave as single fractal structures. For $z<1$ we found $D=1.00\pm0.12$ for the SPLASH galaxies, and $D=1,39\pm0.19$ for the COSMOS2015. For $1\le z\le4$ we respectively found $D=0.83^{+0.36}_{-0.37}$ and $D=0.54^{+0.27}_{-0.26}$. These results were verified to be robust under the assumed Hubble constant uncertainty. Calculations considering blue and red galaxies subsamples in both surveys showed that the fractal dimensions of blue galaxies as basically unchanged, but the ones for the red galaxies changed mostly to smaller values, meaning that $D$ may be seen as a more intrinsic property of the distribution of objects in the Universe, therefore allowing for the fractal dimension to be used as a tool to study different populations of galaxies. All results confirm the decades old theoretical prediction of a decrease in the fractal dimension for $z>1$.

Early dark energy has emerged as one of the more promising approaches to address the Hubble tension - the statistically significant disparity between measurements of the Hubble constant made using data from different epochs in cosmic history. However, the idea is not without its own set of challenges, both from the data, in the effects it has on other measurements, such as the large-scale structure tension, and from theoretical concerns such as technical naturalness and the introduction of a new coincidence problem in cosmology. In this brief note, delivered as an invited plenary lecture at the {\it 15th Frontiers of Fundamental Physics conference}, I discuss how some of the fine-tuning problems of early dark energy can be ameliorated by using couplings to other fields already present in cosmology, and for which the epoch of matter-radiation equality is already a special one. The resulting models - neutrino assisted early dark energy, and chameleon early dark energy - provide testable, theoretically robust implementations of this general idea. I will discuss the formulation and the cosmology of such approaches, including some constraints arising from both observational and theoretical considerations.

The Vera C. Rubin Observatory's Legacy Survey of Space and Time (LSST) has the potential to measure parallaxes for thousands of nearby ultracool dwarfs, enabling improved measurements of the brown dwarf luminosity function. We develop a simple model to estimate the number of L dwarfs and T dwarfs with parallaxes with signal-to-noise ratio greater than ten in the baseline LSST survey. High quality astrometry imposes scheduling constraints. We assess different possible observing strategies using quantitative metrics and make recommendations as part of the LSST community input process. We find that the new substellar parallax sample will represent a nearly order-of-magnitude increase on existing samples, with ~50-100 objects per spectral type bin for late-L to mid-T dwarfs. The sample size is robust (+/- 5%) against most survey strategy changes under consideration, although we do identify areas of tension with other uses of twilight time that could have larger impact.

Measured rotational speeds of giant planets and brown dwarfs frequently constitute appreciable fractions of the breakup limit, resulting in centrifugal expansion of these objects at the equator. According to models of internal energy transport, this expansion ought to make the poles of a rotator significantly hotter than the equator, so that inclination of the rotational axis greatly affects both spectral shape and total flux. In this article, we explore the dependence of a substellar object's observables on its rotational speed and axis inclination. To do so, we combine PICASO (a Planetary Intensity Code for Atmospheric Spectroscopy Observations) with software PARS (Paint the Atmospheres of Rotating Stars). The former computer program models radiative transfer within plane-parallel planetary atmospheres, while the latter computes disk-integrated spectra of centrifugally deformed gaseous masses. We find that the specific flux of a typical fast-rotating brown dwarf can increase by as much as a factor of 1.5 with movement from an equator-on to a pole-on view. On the other hand, the distinctive effect of rotation on spectral shape increases toward the equator-on view. The latter effect also increases with lower effective temperature. The bolometric luminosity estimate for a typical fast rotator at extreme inclinations has to be adjusted by as much as about 20% due to the anisotropy of the object's observed flux. We provide a general formula for the calculation of the corresponding adjustment factor in terms of rotational speed and inclination.

Directly imaging Earth-like exoplanets (``exoEarths'') with a coronagraph instrument on a space telescope requires a stable wavefront with optical path differences limited to tens of picometers RMS during exposure times of a few hours. While the structural dynamics of a segmented mirror can be directly stabilized with telescope metrology, another possibility is to use a closed-loop wavefront sensing and control system in the coronagraph instrument that operates during the science exposures to actively correct the wavefront and relax the constraints on the stability of the telescope. In this paper, we present simulations of the temporal filtering provided using the example of LUVOIR-A, a 15~m segmented telescope concept. Assuming steady-state aberrations based on a finite element model of the telescope structure, we (1)~optimize the system to minimize the wavefront residuals, (2)~ use an end-to-end numerical propagation model to estimate the residual starlight intensity at the science detector, and (3)~predict the number of exoEarth candidates detected during the mission. We show that telescope dynamic errors of 100~pm~RMS can be reduced down to 30~pm~RMS with a magnitude 0 star, improving the contrast performance by a factor of 15. In scenarios where vibration frequencies are too fast for a system that uses natural guide stars, laser sources can increase the flux at the wavefront sensor to increase the servo-loop frequency and mitigate the high temporal frequency wavefront errors. For example, an external laser with an effective magnitude of -4 allows the wavefront from a telescope with 100~pm~RMS dynamic errors and strong vibrations as fast as 16~Hz to be stabilized with residual errors of 10~pm~RMS thereby increasing the number of detected planets by at least a factor of 4.

Some massive stars end their lives as \textit{failed} core-collapse supernovae (CCSNe) and become black holes (BHs). Although in this class of phenomena the stalled supernova shock is not revived, the outer stellar envelope can still be partially ejected. This occurs because the hydrodynamic equilibrium of the star is disrupted by the gravitational mass loss of the protoneutron star (PNS) due to neutrino emission. We develop a simple model that emulates PNS evolution and its neutrino emission and use it to simulate failed CCSNe in spherical symmetry for a wide range of progenitor stars. Our model allows us to study mass ejection of failed CCSNe where the PNS collapses into a BH within $\sim100\,{\rm ms}$ and up to $\sim10^6\,{\rm s}$. We perform failed CCSNe simulations for 262 different pre-SN progenitors and determine how the energy and mass of the ejecta depend on progenitor properties and the equation of state (EOS) of dense matter. In the case of a future failed CCSN observation, the trends obtained in our simulations can be used to place constraints on the pre-SN progenitor characteristics, the EOS, and on PNS properties at BH formation time.

The centers of galaxies host nuclear stellar clusters, supermassive black holes, or both, but the origin of this dichotomy is still a mystery. Nuclear stellar clusters are the densest stellar system of the Universe, so they are ideal places for runaway collisions to occur. In these dense clusters it is possible that global instability occurs, triggered by collisions and mergers forming a massive black hole. Here we test a new mechanism to form massive black holes through runaway stellar collisions in nuclear stellar clusters, performing N-body simulations using the code nbody6++gpu. Our idealized models show that there is a critical mass where collisions become very efficient making it possible to form massive black holes in nuclear stellar clusters. The most massive objects reach masses of the order of $10^4-10^5\rm~ M_\odot$. We find that our highest black hole formation efficiency is up to $50\%$ of the stellar mass at the end of the simulation. In real astrophysical systems, the critical mass scale for this transition is expected to occur in stellar clusters of $10^7-10^9\rm~M_\odot$, implying the formation of quite massive central objects.

In this paper, we attempt to interpret the photometric light curve of 1I/`Oumuamua, the first interstellar object discovered traversing the inner Solar System. We compare photometric data with synthetic light curves of ellipsoidal bodies for a range of rotational states and observing geometries. While previous work reported an increase in the periodicity of the object during October, we find a $\Delta p\simeq0.21$ hour decrease in the spin period between October and November. We investigate potential contributions to the evolving spin period from both outgassing and tidal effects using a general formalism which may be applied to any elongated object. While sublimation is a stronger effect, tidal deformation could change the moment of inertia and subsequent spin period based on the bulk material properties. We present an open source software which simulates constant-density, constant-viscosity liquid bodies subject to tidal forces for a range of assumed viscosites and sizes ($\texttt{SAMUS}$). These numerical simulations, when applied to `Oumuamua, demonstrate that it may have experienced significant tidal deformation in the presence of sublimation. However, synthetic observations which incorporate tidal effects demonstrate that little deformation is necessary to match the composite light curve. We find that a dynamic viscosity of $\mu\geq10^9$ g cm$^{-1}$ s$^{-1}$, corresponding to a 0.1\% change in moment of inertia, best reproduces the photometric data. It is feasible that tidal deformation contributed to the shorter timescale spin-down in October, while outgassing induced the secular spin-up.

The multi-object spectrograph (MOS) has been the benchmark for the current generation of astronomical spectrographs, valued for its ability to acquire the spectra of hundreds of objects simultaneously. In the last two decades, the digital micromirror device (DMD) has shown potential in becoming the central component of the MOS, being used as a programmable slit array. We have designed a seeing-limited DMD-based MOS covering a spectral range of 0.4 to 0.7 $\mu$m, with a field of view (FOV) of $10.5^\prime \times 13.98^\prime$ and a spectral resolution of $R\sim1000$. This DMD-MOS employs all-spherical refractive optics, and a volume phase holographic (VPH) grism as the dispersive element for high throughput. In this paper, we present the optical design and optimization process of this DMD-MOS, as well as a preliminary wavelength calibration procedure for hyperspectral data reduction. Using simulated data of the DMD-MOS, a procedure was developed to measure hyperspectral imaging distortion and to construct pixel-to-wavelength mappings on the detector. An investigation into the relationships between DMD micromirrors and detector pixels was conducted. This DMD-MOS will be placed on a 0.5 m diameter telescope as an exploratory study for future DMD-based MOS systems.

We present 2D hydrodynamical simulations of the transition of a proto-planetary nebula to a planetary nebula for central stars in binary systems that have undergone a common envelope event. After 1,000 yr of magnetically driven dynamics (proto-planetary nebula phase), a line-driven stellar wind is introduced into the computational domain and the expansion of the nebula is simulated for another 10,000 yr, including the effects of stellar photoionization. In this study we consider central stars with main sequence (final) masses of 1 (0.569) and 2.5 (0.677) \Mo, together with a 0.6 \Mo ma in sequence companion. Extremely bipolar, narrow-waisted proto-planetary nebulae result in bipolar planetary nebulae, while the rest of the shapes mainly evolve into elliptical planetary nebulae. The initial magnetic field's effects on the collimated structures, such as jets, tend to disappear in most of the cases, leaving behind the remnants of those features in only a few cases. Equatorial zones fragmented mainly by photoionization ( 1 \Mo progenitors), result in ``necklace'' structures made of cometary clumps aligned with the radiation field. On the other hand, fragmentation by photoionization and shocked wind ( 2.5 \Mo progenitors) give rise to the formation of multiple clumps in the latitudinal direction, which remain within the lobes, close to the center, which are immersed and surrounded by hot shocked gas, not necessarily aligned with the radiation field. These results reveal that the fragmentation process has a dependence on the stellar mass progenitor. This fragmentation is made possible by the distribution of gas in the previous post-common envelope proto-planetary nebula as sculpted by the action of the jets.

Machine-learning based classifiers have become indispensable in the field of astrophysics, allowing separation of astronomical sources into various classes, with computational efficiency suitable for application to the enormous data volumes that wide-area surveys now typically produce. In the standard supervised classification paradigm, a model is typically trained and validated using data from relatively small areas of sky, before being used to classify sources in other areas of the sky. However, population shifts between the training examples and the sources to be classified can lead to `silent' degradation in model performance, which can be challenging to identify when the ground-truth is not available. In this Letter, we present a novel methodology using the NannyML Confidence-Based Performance Estimation (CBPE) method to predict classifier F1-score in the presence of population shifts, but without ground-truth labels. We apply CBPE to the selection of quasars with decision-tree ensemble models, using broad-band photometry, and show that the F1-scores are predicted remarkably well (MAPE ~ 10%; R^2 = 0.74-0.92). We discuss potential use-cases in the domain of astronomy, including machine-learning model and/or hyperparameter selection, and evaluation of the suitability of training datasets for a particular classification problem.

We present a sample of nine Fast Radio Bursts (FRBs) from which we derive magnetic field strengths of the host galaxies represented by normal, $z<0.5$ star-forming galaxies with stellar masses $M_* \approx 10^8 -10^{10.5} M_\odot$. We find no correlation between the FRB rotation measure(RM) and redshift which indicates that the RM values are due mostly to the FRB host contribution. This assertion is further supported by strong correlations (Spearman test probabilities $P_S \simeq 0.05$) found between RM and the estimated host dispersion measure ($DM_{Host}$) and host-normalized galacto-centric offset (Spearman $r_S$ values equal to 0.64 and -0.52). For these nine galaxies, we estimate their magnetic field strengths projected along the sightline $B$ finding a low median value of $0.5 \mu G$. This implies the magnetic fields of our sample of hosts are weaker than those characteristic of the Solar neighborhood ($\approx 6 \mu G$), but relatively consistent with a lower limit on observed range of $2-10 \mu G$ for star-forming, disk galaxies, especially as we consider reversals in the B-field, and that we are only probing $B_{\parallel}$. We compare to RMs from simulated galaxies of the Auriga project -- magneto-hydrodynamic cosmological zoom simulations - and find that the simulations predict the observed values to within the $95\%$ CI. Upcoming FRB surveys will provide hundreds of new FRBs with high-precision localizations, rotation measures, and imaging follow-up to support further investigation on the magnetic fields of a diverse population of $z<1$ galaxies.

We estimated blackbody temperature for 209 flares observed at 69 F-K stars, significantly increasing the number of flare temperature determinations. We used the Blue and Red channels obtained by the 27 cm telescope of the CoRoT satellite at high cadence and long duration. The wavelength limits of the channels were estimated using spectra from the Pickles library for the spectral type and luminosity class of each star, provided by the Exodat Database. The temperatures were obtained from the flare energy Blue-to-Red ratio, using the flare equivalent duration and stellar flux in both channels. The expected value of the analyzed flares is equal to 6,400 K with a standard deviation of 2,800 K, where the mean stellar spectral type, weighted by the number of flares in each spectral subclass, is equal to G6. Contrary to our results, a stellar white-light flare is often assumed to emit as a blackbody with a temperature of 9,000 K or 10,000 K. Our estimates agree, however, with values obtained for solar flares. The GAIA G-band transmissivity is comparable to that of the CoRoT White channel, which allows us to calibrate the flares to the Gaia photometric system. The energy in the G band of the analyzed flares varies between $10^{32}$ and $10^{37}$ erg and the flare area ranges from 30$\mu$sh to 3 sh (solar hemisphere). The energy release per area in a flare is proportional to $T_{\rm flare}^{2.6}$, at least up to 10,000 K.

We discuss the recent "realpolitik" analysis of Wisian & Traphagan (2020, W&T) of the potential geopolitical fallout of the success of SETI. They conclude that "passive" SETI involves an underexplored yet significant risk that, in the event of a successful, passive detection of extraterrestrial technology, state-level actors could seek to gain an information monopoly on communications with an ETI. These attempts could lead to international conflict and potentially disastrous consequences. In response to this possibility, they argue that scientists and facilities engaged in SETI should preemptively engage in significant security protocols to forestall this risk. We find several flaws in their analysis. While we do not dispute that a realpolitik response is possible, we uncover concerns with W&T's presentation of the realpolitik paradigm, and we argue that sufficient reason is not given to justify treating this potential scenario as action-guiding over other candidate geopolitical responses. Furthermore, even if one assumes that a realpolitik response is the most relevant geopolitical response, we show that it is highly unlikely that a nation could successfully monopolize communication with ETI. Instead, the real threat that the authors identify is based on the perception by state actors that an information monopoly is likely. However, as we show, this perception is based on an overly narrow contact scenario. Overall, we critique W&T's argument and resulting recommendations on technical, political, and ethical grounds. Ultimately, we find that not only are W&T's recommendations unlikely to work, they may also precipitate the very ills that they foresee. As an alternative, we recommend transparency and data sharing (which are consistent with currently accepted best practices), further development of post-detection protocols, and better education of policymakers in this space.

In our self-similar, analytical, magneto-hydrodynamic (MHD) accretion-ejection solution, the density at the base of the outflow is explicitly dependent on the disk accretion rate - a unique property of this class of solutions. We had earlier found that the ejection index $p >\sim 0.1 (\dot{M}_{acc} \propto r^p ) $ is a key MHD parameter that decides if the flow can cause absorption lines in the high resolution X-ray spectra of black hole binaries. Here we choose 3 dense warm solutions with $p = 0.1, 0.3, 0.45$ and carefully develop a methodology to generate spectra which are convolved with the Athena and XRISM response functions to predict what they will observe seeing through such MHD outflows. In this paper two other external parameters were varied - extent of the disk, $\rm{r_o|_{max}} = 10^5, \, 10^6 \,\, \rm{r_G}$, and the angle of the line of sight, $i \sim 10 - 25^{\circ}$. Resultant absorption lines (H and He-like Fe, Ca, Ar) change in strength and their profiles manifest varying degrees of asymmetry. We checked if a) the lines and ii) the line asymmetries are detected, in our suit of synthetic Athena and XRISM spectra. Our analysis shows that Athena should detect the lines and their asymmetries for a standard 100 ksec observation of a 100 mCrab source - lines with equivalent width as low as a few eV should be detected if the 6-8 keV counts are larger than $10^4 - 10^5$ even for the least favourable simulated cases.

Photometric observations for the totally eclipsing binary system TYC 4002-2628-1, were obtained between November 2020 and November 2021. To determine the stellar atmospheric parameters, a spectral image was taken with the 2.16 m telescope at National Astronomical Observatory of China (NAOC). TYC 4002-2628-1 is a low-amplitude (about 0.15 mag for $V$ band), short-period (0.3670495 d), contact eclipsing binary with a total secondary eclipse. Intrinsic light curve variations and the reversal of the O'Connell effect are detected in the light curves, which may be due to spot activity. Based on the photometric solutions derived from the multi-band time series light curves, TYC 4002-2628-1 is an extremely low mass ratio contact binary with a mass ratio of $q\sim$ 0.0482 and a fill-out factor of $f\sim5\%$. By analyzing the $O-C$ variations, we find that its orbital period remains unchanged when BJD < 2458321 . Then the orbital period changed suddenly around BJD 2458743 and has an increasing rate of $dP/dt=1.62\times{10^{-5}}day\cdot yr^{-1}=140$ $second\cdot century^{-1}$ . If confirmed, TYC 4002-2628-1 would be the contact binary with the highest orbital period increasing rate so far. By investigating the ratio of orbital angular momentum to the spin angular momentum ( $J_{orb}$/$J_{spin}$ $<3$) , the instability mass ratio ($q_{inst}/q=1.84$) and the instability separation ($A_{inst}/A=1.35$), TYC 4002-2628-1 can be regarded as a merger candidate.

In this $\textit{Letter}$, we search for the signal of the primordial black holes (PBHs) by correlating the $\gamma$-ray emissions in the MeV energy band produced by the Hawking evaporation and the lensing effect of the cosmic microwave background (CMB). We use the conservative case of the astrophysical model as much as possible in the calculations, since the potential astrophysical origins dominate the observed emission in the MeV energy band. By carefully discussing the appropriate energy bands corresponding to different PBHs masses, it is worth expecting a tight constraint on the fraction of the Schwarzschild PBHs in the mass range of $10^{16} - 5\times10^{17}\,{\rm g}$, by simulations of the sensitivity of the future CMB-S4 project and the $\gamma$-ray telescope e-ASTROGAM. Furthermore, we also consider the PBHs model with spins, and find that the constraining ability of the PBHs fraction from the correlation between CMB lensing and $\gamma$-ray emissions can be improved by another order of magnitude, which could importantly fill the gaps with PBHs fraction limits in the mass range of $5\times 10^{17} - 2\times 10^{18}\,{\rm g}$.

We report the detection of the CO(12-11) line emission toward G09-83808 (or H-ATLAS J090045.4+004125), a strongly-lensed submillimeter galaxy at $z = 6.02$, with Atacama Large Millimeter/submillimeter Array observations. Combining previously detected [O III]$\,88\:\mathrm{\mu m}$, [N II]$\,205\:\mathrm{\mu m}$, and dust continuum at 0.6$\:$mm and 1.5$\:$mm, we investigate the physical properties of the multi-phase interstellar medium in G09-83808. A source-plane reconstruction reveals that the region of the CO(12-11) emission is compact ($R_\mathrm{{e, CO}}=0.49^{+0.29}_{-0.19}\,\mathrm{kpc}$) and roughly coincides with that of the dust continuum. Non-local thermodynamic equilibrium radiative transfer modeling of CO spectral-line energy distribution reveals that most of the CO(12-11) emission comes from a warm (kinetic temperature of $T_{\mathrm{kin}}=320\pm170\:$K) and dense ($\log(n_{\mathrm{H2}}/\mathrm{cm^{-3}})=5.4\pm0.6$) gas, indicating that the warm and dense molecular gas is concentrated in the central 0.5-kpc region. The luminosity ratio in G09-83808 is estimated to be $L_\mathrm{{CO(12-11)}} / L_\mathrm{{CO(6-5)}}=1.1\pm0.2$. The high ratio is consistent with those in local active galactic nuclei (AGNs) and $6<z<7$ quasars, the fact of which implies that G09-83808 would be a good target to explore dust-obscured AGNs in the epoch of reionization. In the reconstructed [O III]$\,88\:\mathrm{\mu m}$ and [N II]$\,205\:\mathrm{\mu m}$ cubes, we also find that a monotonic velocity gradient is extending over the central starburst region by a factor of two and that star-forming sub-components exist. High-resolution observations of bright [C II]$\,158\:\mathrm{\mu m}$ line emissions will enable us to characterize the kinematics of a possible rotating disk and the nature of the sub-components.

Auroras are emissions in a planetary atmosphere caused by its interactions with the surrounding plasma environment. They have been observed in most planets and some moons of the solar system. Since their first discovery in 2005, Mars auroras have been studied extensively and is now a rapidly growing area of research. Since Mars lacks an intrinsic global magnetic field, its crustal field is distributed throughout the planet and its interactions with the surrounding plasma environment lead to a number of complex processes resulting in several types of auroras uncommon on Earth. Martian auroras have been classified as diffuse, discrete and proton aurora. With new capability of synoptic observations made possible with the Hope probe, two new types of auroras have been observed. One of them, which occurs on a much larger spatial scale, covering much of the disk, is known as discrete sinuous aurora. The other subcategory is one of proton auroras observed in patches. Further study of these phenomena will provide insights into the interactions between the atmosphere, magnetosphere and the surrounding plasma environment of Mars. We provide a brief review of the work done on the subject in the past 17 years since their discovery, and report new developments based on observations with Hope probe.

Ram pressure stripping (RPS) is known to be a key environmental effect that can remove interstellar gas from galaxies in a cluster. The RPS process is commonly described as a competition between the ram pressure by the intracluster medium (ICM) and the anchoring pressure on the interstellar medium (ISM) by the gravitational potential of a galaxy. However, the actual gas stripping process can be more complicated due to the complexity of gas physics such as compression and geometrical self-shielding as well as cooling and heating. In order to verify how well the observed signatures of the RPS process can be understood as simple momentum transfer, we compare the stripping radii of Virgo cluster galaxies in different stages of RPS measured from the HI observation with the predicted gas truncation radii for the given conditions. For the sample undergoing active RPS, we generally find good agreements between predictions and observations within a measurement uncertainty. On the other hand, galaxies likely in the early or later RPS stage and/or the ones with signs of environmental impacts other than RPS such as tidal interaction or starvation, show some discrepancies. Our results imply that the conventional RPS relation works reasonably well in a broad sense when RPS is the most dominant process and the galaxy is located where the surrounding environment can be well defined. Otherwise, more careful inspections on the second mechanism and local environment are required to assess the impact of RPS on the target.

$\require{mediawiki-texvc}$A stellar chromospheric activity database of solar-like stars is constructed based on the Large Sky Area Multi-Object Fiber Spectroscopic Telescope (LAMOST) Low-Resolution Spectroscopic Survey (LRS). The database contains spectral bandpass fluxes and indexes of Ca II H&K lines derived from 1,330,654 high-quality LRS spectra of solar-like stars. We measure the mean fluxes at line cores of the Ca II H&K lines using a 1 ${\AA}$ rectangular bandpass as well as a 1.09 ${\AA}$ full width at half maximum (FWHM) triangular bandpass, and the mean fluxes of two 20 ${\AA}$ pseudo-continuum bands on the two sides of the lines. Three activity indexes, $S_{\rm rec}$ based on the 1 ${\AA}$ rectangular bandpass, and $S_{\rm tri}$ and $S_L$ based on the 1.09 ${\AA}$ FWHM triangular bandpass, are evaluated from the measured fluxes to quantitatively indicate the chromospheric activity level. The uncertainties of all the obtained parameters are estimated. We also produce spectrum diagrams of Ca II H&K lines for all the spectra in the database. The entity of the database is composed of a catalog of spectral sample and activity parameters, and a library of spectrum diagrams. Statistics reveal that the solar-like stars with high level of chromospheric activity ($S_{\rm rec}>0.6$) tend to appear in the parameter range of $T_{\rm eff}\text{ (effective temperature)}<5500\,{\rm K}$, $4.3<\log\,g\text{ (surface gravity)}<4.6$, and $-0.2<[{\rm Fe/H}]\text{ (metallicity)}<0.3$. This database with more than one million high-quality LAMOST LRS spectra of Ca II H&K lines and basal chromospheric activity parameters can be further used for investigating activity characteristics of solar-like stars and solar-stellar connection.

In this chapter we consider the processes which can lead to X-ray emission from different types of cataclysmic variable stars (CVs). CVs are semi-detached, binary star systems where material is transferred from the donor star (also known as the companion or secondary star) onto the white dwarf primary. CVs are divided into several sub-classes based on the observed phenomenology in the optical and X-ray bands, which, in turn, is largely defined by the magnetic field strength of the accretor. In non-magnetic systems, a variety of observed behaviours are identified, depending on the accretion rate: novae, dwarf novae, nova-like variables, symbiotic binaries and supersoft sources are all examples of non-magnetic CVs. In magnetic systems (polars and intermediate polars, or AM Her and DQ Her systems, respectively), the accretion flow is channelled to polar regions, and the observational appearance is different. X-rays are typically produced through hot or energetic processes, and in CVs they are formed via shocks (within a boundary layer or accretion column, or through interactions either internal to the nova ejecta, or between the ejecta and a stellar wind) or from hydrogen burning (either steady fusion, or a thermonuclear runaway). All of these different types of accreting white dwarfs are discussed here, considering both spectral and temporal variability in the different populations.

The scientific achievements of the Pierre Auger Collaboration cover diverse and complementary fields of research. The search for the origin of ultra-high energy cosmic rays (UHECRs) is based on the measurement of the energy spectrum and mass composition of the primaries, on studies of multi-messengers, and on extensive anisotropy searches. With the collected data it is also possible to explore the characteristics of hadronic interactions at energies unreachable at human-made accelerators, and to assess the existence of non-standard physics effects. A selection of the latest results is presented and the emerging picture is discussed.

We study formation of primordial black holes and generation of gravitational waves in a class of cosmological models that are direct supersymmetric analogues of the observationally favored nonminimally coupled Higgs inflation model. It is known that this type of model naturally includes multiple scalar fields which may be regarded as the inflaton. For the sake of simplicity we focus on the case where the inflaton field space is two dimensional. We analyze the multifield dynamics and find the region of parameters that gives copious production of primordial black holes that may comprise a significant part of the present dark matter abundance. We also compute the spectrum of the gravitational waves and discuss their detectability by means of future ground-based and space-borne gravitational wave observatories.

The magnetic field plays a significant role in the phenomenon of highly collimated jets of active galactic nuclei (AGN). Relativistic effects prevent the direct reconstruction of the magnetic field direction as transverse to electric vectors on radio maps. We determined the topology of the \textbf{B}-field by modeling the transverse distributions of the total and linearly polarized intensity, polarization degree, and deviation of the polarization direction from the local jet axis and by further comparison with observational data. We consider (i) a helical field with a different twist angle; (ii) a toroidal field on the jet axis surrounded by a sheath with a longitudinal field. In the latter scenario, we consider different sheath thickness relative to the spine. We assumed the sheath velocity is equal to or less than that of the spine. The relativistic effects have been considered for a general case, under which the axis and velocity vector of the jet and radial directions do not coincide. Our simulations reproduce the main features of the observed transverse profiles of polarization characteristics in parsec-scale AGN jets. The model transverse distribution shapes of the polarization properties are found to be strongly influenced by kinematic and geometric parameters of an outflow. We demonstrated it for three AGNs having different but typical polarization patterns revealed on radio maps. For each of these objects, we identified the model parameters, which provide a qualitative correspondence of theoretical profiles with those obtained from observations, indicating that the \textbf{B}-field is strongly ordered on parsec scales.

We present EMIR, a powerful near-infrared (NIR) camera and multi-object spectrograph (MOS) installed at the Nasmyth focus of the 10.4 m GTC. EMIR was commissioned in mid-2016 and is offered as a common-user instrument. It provides spectral coverage of 0.9 to 2.5 $\mu m$ over a field of view (FOV) of 6.67x6.67 squared arcmin in imaging mode, and 6.67x4 squared arcmin in spectroscopy. EMIR delivers up to 53 spectra of different objects thanks to a robotic configurable cold slit mask system that is located inside the cryogenic chamber, allowing rapid reconfiguration of the observing mask. The imaging mode is attained by moving all bars outside the FOV and then leaving an empty space in the GTC focal surface. The dispersing suite holds three large pseudo-grisms, formed by the combination of high-efficiency FuSi ion-etched ruled transmission grating sandwiched between two identical ZnSe prisms, plus one standard replicated grism. These dispersing units offer the spectral recording of an atmospheric window $J,H,K$ in a single shot with resolving powers of 5000, 4250, 4000, respectively for a nominal slit width of 0.6\arcsec, plus the combined bands $YJ$ or $HK$, also in a single shot, with resolution of $\sim$ 1000. The original Hawaii2 FPA detector, which is prone to instabilities that add noise to the signal, is being replaced by a new Hawaii2RG detector array, and is currently being tested at the IAC. This paper presents the most salient features of the instrument, with emphasis on its observing capabilities and the functionality of the configurable slit unit. Sample early science data is also shown.

Atmospheric retrieval studies are essential to determine the science requirements for future generation missions, such as the Large Interferometer for Exoplanets (LIFE). The use of heterogeneous absorption cross-sections might be the cause of systematic effects in retrievals, which could bias a correct characterization of the atmosphere. In this contribution we quantified the impact of differences in line list provenance, broadening coefficients, and line wing cut-offs in the retrieval of an Earth twin exoplanet orbiting a Sun-like star at 10 pc from the observer, as it would be observed with LIFE. We ran four different retrievals on the same input spectrum, by varying the opacity tables that the Bayesian retrieval framework was allowed to use. We found that the systematics introduced by the opacity tables could bias the correct estimation of the atmospheric pressure at the surface level, as well as an accurate retrieval of the abundance of some species in the atmosphere (such as CO$_2$ and N$_2$O). We argue that differences in the line wing cut-off might be the major source of errors. We highlight the need for more laboratory and modeling efforts, as well as inter-model comparisons of the main radiative transfer models and Bayesian retrieval frameworks. This is especially relevant in the context of LIFE and future generation missions, to identify issues and critical points for the community to jointly work together to prepare for the analysis of the upcoming observations.

Frequent accretion of external cold gas is thought to play an important role in galaxy assembly. However, almost all known kinematically misaligned galaxies identify only one gas disk that is misaligned with the stellar disk, implying a single gas acquisition event. Here we report a new configuration in two galaxies where both contain two gas disks misaligned with each other and also with the stellar disk. Such systems are not expected to be stable or long-lasting, challenging the traditional picture of gas accretion of galaxies and their angular momentum build-up. The differences in kinematic position angles are larger than 120{\deg} between the two gas disks, and 40{\deg} between each gas disk and the stellar component. The star formation activity is enhanced at the interface of the two gas disks compared with the other regions within the same galaxy. Such systems illustrate that low-redshift galaxies can still experience multiple gas acquisition events, and provide a new view into the origins of galactic gas.

We present the X-ray imaging and spectral analysis of the diffuse emission around the Spiderweb galaxy at z=2.16 and of its nuclear emission, based on a deep (700 ks) Chandra observation. We characterize the nuclear emission and computed the contamination in the surrounding regions due to the wings of the instrument PSF. Then, we quantified the extended emission within 12". We find that the Spiderweb galaxy hosts a mildly absorbed quasar, with modest yet significant variability on a timescale of ~1 year. We find that the emission in the jet regions is well described by a power law with Gamma~2-2.5, and it is consistent with IC upscattering of the CMB photons by the relativistic electrons. We also find a roughly symmetric, diffuse emission within a radius of ~100 kpc. This emission is consistent with thermal bremsstrahlung from a hot ICM with a temperature of kT=2.0_{-0.4}^{+0.7} keV, and a metallicity of Z<1.6Z_sun. The average electron density within 100 kpc is n_e=(1.51+-0.24+-0.14)E-2 cm^{-3}, corresponding to an upper limit for the total ICM mass of <=(1.76+-0.30+-0.17)E+12 M_sun (where error bars are 1 sigma statistical and systematic, respectively). If we apply hydrostatic equilibrium to the ICM, we measure a total gravitational mass M(<100 kpc)=(1.5^{+0.5}_{-0.3})E+13 M_sun and, extrapolating at larger radii, we estimate a total mass M_{500}=(3.2^{+1.1}_{-0.6})E+13 M_sun within a radius of r_{500}=(220+-30) kpc. We conclude that the Spiderweb protocluster shows significant diffuse emission within a radius of 12 arcsec, whose major contribution is provided by IC scattering associated with the radio jets. Outside the jet regions, we also identified thermal emission within a radius of ~100 kpc, revealing the presence of hot, diffuse baryons that may represent the embryonic virialized halo of the forming cluster.

The formation and evolution pathway for the directly-imaged multi-planetary system HR 8799 remains mysterious. Accurate constraints on the chemical composition of the planetary atmosphere(s) are key to solving the mystery. We perform a detailed atmospheric retrieval on HR 8799 c to infer the chemical abundances and abundance ratios using a combination of photometric data along with low- and high-resolution spectroscopic data (R$\sim$20-35,000). We specifically retrieve [C/H], [O/H], and C/O and find them to be 0.55$^{+0.36}_{-0.39}$, 0.47$^{+0.31}_{-0.32}$, and 0.67$^{+0.12}_{-0.15}$ at 68\% confidence. The super-stellar C and O abundances, yet a stellar C/O ratio, reveal a potential formation pathway for HR 8799 c. Planet c, and likely the other gas giant planets in the system, formed through disk fragmentation, followed by further atmospheric enrichment in C and O through the accretion of planetesimals and dust during formation or along a phase of inward migration.

In protoplanetary discs, the coagulation of dust grains into large aggregates still remains poorly understood. Grain porosity appears to be a promising solution to allow the grains to survive and form planetesimals. Furthermore, dust shattering has generally been considered to come only from collisional fragmentation, but a new process was recently introduced, rotational disruption. We wrote a 1D code that models the growth and porosity evolution of grains as they drift to study their final outcome when the two shattering processes are included. When simulating the evolution of grains in a disc model that reproduces observations, we find that rotational disruption is not negligible compared to the fragmentation and radial drift. Disruption becomes dominant when the turbulence parameter $\alpha \lesssim 5\xtenpow{-4}$, if the radial drift is slow enough. We show that the importance of disruption in the growth history of grains strongly depends on their tensile strength.

We present high-resolution dayside thermal emission observations of the exoplanet WASP-18b using IGRINS on Gemini South. We remove stellar and telluric signatures using standard algorithms, and we extract the planet signal via cross correlation with model spectra. We detect the atmosphere of WASP-18b at a signal-to-noise ratio (SNR) of 5.9 using a full chemistry model, measure H2O (SNR=3.3), CO (SNR=4.0), and OH (SNR=4.8) individually, and confirm previous claims of a thermal inversion layer. The three species are confidently detected (>4$\sigma$) with a Bayesian inference framework, which we also use to retrieve abundance, temperature, and velocity information. For this ultra-hot Jupiter (UHJ), thermal dissociation processes likely play an important role. Retrieving abundances constant with altitude and allowing the temperature-pressure profile to freely adjust results in a moderately super-stellar carbon to oxygen ratio (C/O=0.75^{+0.14}_{-0.17}) and metallicity ([M/H]=1.03^{+0.65}_{-1.01}). Accounting for undetectable oxygen produced by thermal dissociation leads to C/O=0.45^{+0.08}_{-0.10} and [M/H]=1.17^{+0.66}_{-1.01}. A retrieval that assumes radiative-convective-thermochemical-equilibrium and naturally accounts for thermal dissociation constrains C/O<0.34 (2$\sigma$) and [M/H]=0.48^{+0.33}_{-0.29}, in line with the chemistry of the parent star. Looking at the velocity information, we see a tantalising signature of different Doppler shifts at the level of a few km/s for different molecules, which might probe dynamics as a function of altitude and location on the planet disk. Our results demonstrate that ground-based, high-resolution spectroscopy at infrared wavelengths can provide meaningful constraints on the compositions and climate of highly irradiated planets. This work also elucidates potential pitfalls with commonly employed retrieval assumptions when applied to UHJ spectra.

Ultra-high-energy neutrinos serve as messengers of some of the highest energy astrophysical environments. Given that neutrinos are neutral and only interact via weak interactions, neutrinos can emerge from sources, traverse astronomical distances, and point back to their origins. Their weak interactions require large target volumes for neutrino detection. Using the Earth as a neutrino converter, terrestrial, sub-orbital, and satellite-based instruments are able to detect signals of neutrino-induced extensive air showers. In this paper, we describe the software code $\texttt{nuPyProp}$ that simulates tau neutrino and muon neutrino interactions in the Earth and predicts the spectrum of the $\tau$-lepton and muons that emerge. The $\texttt{nuPyProp}$ outputs are lookup tables of charged lepton exit probabilities and energies that can be used directly or as inputs to the $\texttt{nuSpaceSim}$ code designed to simulate optical and radio signals from extensive air showers induced by the emerging charged leptons. We describe the inputs to the code, demonstrate its flexibility and show selected results for $\tau$-lepton and muon exit probabilities and energy distributions. The $\texttt{nuPyProp}$ code is open source, available on github.

Observations and simulations of interacting galaxies and mergers in the local universe have shown that interactions can significantly enhance the star formation rates (SFR) and fueling of Active Galactic Nuclei (AGN). However, at higher redshift, some simulations suggest that the level of star formation enhancement induced by interactions is lower due to the higher gas fractions and already increased SFRs in these galaxies. To test this, we measure the SFR enhancement in a total of 2351 (1327) massive ($M_*>10^{10}M_\odot$) major ($1<M_1/M_2<4$) spectroscopic galaxy pairs at 0.5<z<3.0 with $\Delta V <5000$ km s$^{-1}$ (1000 km s$^{-1}$) and projected separation <150 kpc selected from the extensive spectroscopic coverage in the COSMOS and CANDELS fields. We find that the highest level of SFR enhancement is a factor of 1.23$^{+0.08}_{-0.09}$ in the closest projected separation bin (<25 kpc) relative to a stellar mass-, redshift-, and environment-matched control sample of isolated galaxies. We find that the level of SFR enhancement is a factor of $\sim1.5$ higher at 0.5<z<1 than at 1<z<3 in the closest projected separation bin. Among a sample of visually identified mergers, we find an enhancement of a factor of 1.86$^{+0.29}_{-0.18}$ for coalesced systems. For this visually identified sample, we see a clear trend of increased SFR enhancement with decreasing projected separation (2.40$^{+0.62}_{-0.37}$ vs.\ 1.58$^{+0.29}_{-0.20}$ for 0.5<z<1.6 and 1.6<z<3.0, respectively). The SFR enhancement seen in our interactions and mergers are all lower than the level seen in local samples at the same separation, suggesting that the level of interaction-induced star formation evolves significantly over this time period.

The Galactic center $\gamma$-ray excess, detected by the Fermi-LAT, is a very attractive tentative signal from dark matter annihilation. Searching for associated synchrotron emissions could test the dark matter interpretation for this excess. We point the Five-hundred-meter Aperture Spherical radio Telescope towards Coma Berenices, a dwarf Spheroidal galaxy, for 2-hours of observation, and we find no significant continuum radio emission, which could be attributed to dark matter annihilation, from our target. We set very stringent annihilation cross-section constraints, with roughly an order of magnitude improvement over a large range of masses compared with previous radio searches. The dark matter scenario for the Galactic center $\gamma$-ray excess is in tension with the FAST observation for reasonable choices of astrophysical factors, including diffusion coefficient, diffusion radius and magnetic field. But with the combination of a small diffusion radius and a large diffusion coefficient, the $\mu^{+}\mu^{-}$ channel for the excess could still survive. Further radio observations by the FAST and other radio telescopes may reveal more about the dark matter properties.

The white dwarf binary pathways survey is dedicated to studying the origin and evolution of binaries containing a white dwarf and an intermediate-mass secondary star of the spectral type A, F, G, or K (WD+AFGK). Here we present CPD-65\,264, a new post common envelope binary with an orbital period of 1.37\,days that contains a massive white dwarf ($ 0.86\pm 0.06\,\mathrm{M}_{\odot}$) and an intermediate-mass ($1.00\pm0.05\,\mathrm{M}_{\odot}$) main-sequence secondary star. We characterized the secondary star and measured the orbital period using high-resolution optical spectroscopy. The white dwarf parameters are determined from HST spectroscopy. In addition, TESS observations revealed that up to 19 per cent of the surface of the secondary is covered with starspots. Small period changes found in the light curve indicate that the secondary is the second example of a G-type secondary star in a post-common envelope binary with latitudinal differential rotation. Given the relatively large mass of the white dwarf and the short orbital period, future mass transfer will be dynamically and thermally stable and the system will evolve into a cataclysmic variable. The formation of the system can be understood assuming common envelope evolution without contributions from energy sources besides orbital energy. CPD-65\,264 is the seventh post-common envelope binaries with intermediate-mass secondaries that can be understood assuming a small efficiency in the common envelope energy equation, in agreement with findings for post-common envelope binaries with M-dwarf or sub-stellar companions.

A confident discovery of physics beyond what has been consistently modeled from gravitational wave (GW) data requires a technique that can distinguish between noise artifacts and unmodeled signatures while also shedding light on the underlying physics. We propose a new data analysis method, \texttt{SCoRe} (Structured Correlated Residual), to search for unmodeled physics in the GW data which can cover both of these aspects. The method searches for structure in the cross-correlation power spectrum of the residual strain between pairs of GW detectors. It does so by projecting this power spectrum onto a frequency-dependent template. The template may be model-independent or model-dependent and is constructed based on the properties of the GW source parameters. The projection of the residual strain enables the distinction between noise artifacts and any true signal while capturing possible dependence on the GW source parameters. Our method is constructed in a Bayesian framework and we have shown its application on a model-independent toy example and for a model motivated by an effective field theory of gravity. The method developed here will be useful to search for a large variety of new physics and yet-to-be-modeled known physics in the GW data accessible from the current network of LIGO-Virgo-KAGRA detectors and from future earth- and space-based GW detectors such as A+, LISA, Cosmic Explorer, and Einstein Telescope.

We quantify the degree of fine tuning required to achieve an observationally viable period of inflation in the strongly dissipative regime of warm inflation. The ``fine-tuning'' parameter $\lambda$ is taken to be the ratio of the change in the height of the potential $\Delta V$ to the change in the scalar field $(\Delta \phi)^{4}$, i.e. the width of the potential, and therefore measures the requisite degree of flatness in the potential. The best motivated warm inflationary scenarios involve a dissipation rate of the kind $\Gamma\propto T^c$ with $c\geq 0$, and for all such cases, the bounds on $\lambda$ are tighter than those for standard cold inflation by at least 3 orders of magnitude. In other words, these models require an even flatter potential than standard inflation. On the other hand for the case of warm inflation with $c< 0$, we find that in a strongly dissipative regime the bound on $\lambda$ can significantly weaken with respect to cold inflation. Thus, if a warm inflation model can be constructed in a strongly dissipative, negatively temperature-dependent regime, it accommodates steeper potentials otherwise ruled out in standard inflation.

Improving and homogenizing time and space reference systems on Earth and, more directly, realizing the Terrestrial Reference Frame (TRF) with an accuracy of 1mm and a long-term stability of 0.1mm/year are relevant for many scientific and societal endeavors. The knowledge of the TRF is fundamental for Earth and navigation sciences. For instance, quantifying sea level change strongly depends on an accurate determination of the geocenter motion but also of the positions of continental and island reference stations, as well as the ground stations of tracking networks. Also, numerous applications in geophysics require absolute millimeter precision from the reference frame, as for example monitoring tectonic motion or crustal deformation for predicting natural hazards. The TRF accuracy to be achieved represents the consensus of various authorities which has enunciated geodesy requirements for Earth sciences. Today we are still far from these ambitious accuracy and stability goals for the realization of the TRF. However, a combination and co-location of all four space geodetic techniques on one satellite platform can significantly contribute to achieving these goals. This is the purpose of the GENESIS mission, proposed as a component of the FutureNAV program of the European Space Agency. The GENESIS platform will be a dynamic space geodetic observatory carrying all the geodetic instruments referenced to one another through carefully calibrated space ties. The co-location of the techniques in space will solve the inconsistencies and biases between the different geodetic techniques in order to reach the TRF accuracy and stability goals endorsed by the various international authorities and the scientific community. The purpose of this white paper is to review the state-of-the-art and explain the benefits of the GENESIS mission in Earth sciences, navigation sciences and metrology.

Although general relativity passes all precision tests to date, there are several reasons to go beyond the current model of gravitation and search for new fundamental physics. This means looking for new, so far undetected, fields. Scalars are the easiest fields to consider and they are ubiquitous in both extensions of the Standard Model and in alternative theories of gravity. That is why a lot of attention has been drawn towards the investigation of scalar-tensor theories, where gravity is described by both the metric tensor and a scalar field. A particularly interesting phenomenon that has recently gained increasing interest is spontaneous scalarization. In gravity theories that exhibit this mechanism, astrophysical objects are identical to their general relativistic counterpart until they reach a specific threshold, usually either in compactness, curvature or, as recently shown, in spin. Beyond this threshold, they acquire a nontrivial scalar configuration, which also affects their structure. In this thesis, we focus on the study of this mechanism in generalized scalar-tensor theories. We identify a minimal action that contains all of the terms that can potentially trigger spontaneous scalarization. We first focus on the onset of scalarization in this specific theory and determine the relevant thresholds in terms of the contributing coupling constants and the properties of the compact object. Finally, we study the effect of this model on the properties of both scalarized black holes and neutron stars, such as affecting their domain of existence or the amount of scalar charge they carry.

We use standard tools of Archaeoastronomy to approach the study of orientations, possibly astronomical, of a group of colonial Christian churches. We present preliminary results of the analysis of the precise spatial orientation of nearly fifty chapels and churches of the Canary Island of Fuerteventura (Spain), most of them built from the period of the Norman conquest in the fifteenth century to the nineteenth century. Although some small chapels belonging to the manorial power of the island and other modern churches do not have a well-defined pattern of orientations, the vast majority of the religious constructions of the island (about 35 of the 48 analyzed) have their axis oriented within the solar range, between the extreme azimuths of the annual movement of the Sun when crossing the local horizon. Unlike what was found in other islands of the archipelago, these results suggest that the religious architecture of Fuerteventura faithfully follows the prescriptions contained in the texts of early Christian writers.

The space mission MICROSCOPE dedicated to the test of the Equivalence Principle (EP) operated from April 25, 2016 until the deactivation of the satellite on October 16, 2018. In this analysis we compare the free-fall accelerations ($a_{\rm A}$ and $a_{\rm B}$) of two test masses in terms of the E\"otv\"os parameter $\eta({\rm{A, B}}) = 2 \frac{a_{\rm A}- a_{\rm B}}{a_{\rm A}+ a_{\rm B}}$. No EP violation has been detected for two test masses, made from platinum and titanium alloys, in a sequence of 19 segments lasting from 13 to 198 hours down to the limit of the statistical error which is smaller than $10^{-14}$ for $ \eta({\rm{Ti, Pt}})$. Accumulating data from all segments leads to $\eta({\rm{Ti, Pt}}) =[-1.5\pm{}2.3{\rm (stat)}\pm{}1.5{\rm (syst)}] \times{}10^{-15}$ showing no EP violation at the level of $2.7\times{}10^{-15}$ if we combine stochastic and systematic errors quadratically. This represents an improvement of almost two orders of magnitude with respect to the previous best such test performed by the E\"ot-Wash group. The reliability of this limit has been verified by comparing the free falls of two test masses of the same composition (platinum) leading to a null E\"otv\"os parameter with a statistical uncertainty of $1.1\times{}10^{-15}$.

Inflaton-vector interactions of the type $\phi F\tilde{F}$ have provided interesting phenomenology to tackle some of current problems in cosmology, namely the vectors could constitute the dark matter component. It could also lead to possible signatures imprinted in a gravitational wave spectrum. Through this coupling, a rolling inflaton induces an exponential production of the transverse polarizations of the vector field, having a maximum at the end of inflation when the inflaton field velocity is at its maximum. These gauge particles, already parity asymmetric, will source the tensor components of the metric perturbations, leading to the production of parity violating gravitational waves. In this work we examine the vector particle production with an attempt to mimic its backreaction effects on the inflation evolution in the weak coupling regime. Furthermore, we fully integrate the gauge particle amplitudes spectrum during this production epoch, studying the behavior until the end of reheating. Finally, we calculate the gravitational wave spectrum solely relying on the vector mode WKB expansion in its regime of validity.