adsabs/SciX_UAT_keywords huggingface dataset:
Constraining Dark Energy from the Local Group Dynamics

This Letter develops a method to constrain the cosmological constant Λ from binary galaxies, focusing on the Milky Way and Andromeda galaxies. We provide an analytical solution to the two-body problem with Λ and show that the ratio between the Keplerian period and ${T}_{{\rm{\Lambda }}}=2\pi /(c\sqrt{{\rm{\Lambda }}})\approx 63.2\,\mathrm{Gyr}$ controls the importance of effects from the cosmological constant. The Andromeda-Milky Way orbit has a period of ~17 Gyr, and so dark energy has to be taken into account. Using the current best mass estimates of the Milky Way and Andromeda galaxies, we find the cosmological constant value has an upper bound that is 5.44 times the value obtained by Planck. With future astrometric measurements, the bound on the cosmological constant can be reduced to $\left(1.67\pm 0.79\right){{\rm{\Lambda }}}_{\mathrm{PL}}$ . Our results offer the prospects of constraints on Λ over very different scales than previously. The Local Group provides also a completely novel platform to test alternative theories of gravity. We illustrate this by deriving bounds on scalar-tensor theories of gravity over megaparsec scales.

Keywords: local group
The Cosmic Telescope That Lenses the Sunburst Arc, PSZ1 G311.65-18.48: Strong Gravitational Lensing Model and Source Plane Analysis

We present a strong-lensing analysis of the cluster PSZ1 G311.65-18.48, based on Hubble Space Telescope imaging, archival VLT/MUSE spectroscopy, and Chandra X-ray data. This cool-core cluster (z = 0.443) lenses the brightest lensed galaxy known, dubbed the "Sunburst Arc" (z = 2.3703), a Lyman continuum (LyC) emitting galaxy multiply imaged 12 times. We identify in this field 14 additional strongly lensed galaxies to constrain a strong-lens model and report secure spectroscopic redshifts of four of them. We measure a projected cluster core mass of M(<250 kpc) = ${2.93}_{-0.02}^{+0.01}\times {10}^{14}$ M ⊙. The two least magnified but complete images of the Sunburst Arc's source galaxy are magnified by ~13×, while the LyC clump is magnified by ~4-80×. We present time delay predictions and conclusive evidence that a discrepant clump in the Sunburst Arc, previously claimed to be a transient, is not variable, thus strengthening the hypothesis that it results from an exceptionally high magnification. A source plane reconstruction and analysis of the Sunburst Arc finds its physical size to be 1 × 2 kpc and that it is resolved in three distinct directions in the source plane, 0°, 40°, and 75° (east of north). We place an upper limit of r ≲ 50 pc on the source plane size of unresolved clumps and r ≲ 32 pc for the LyC clump. Finally, we report that the Sunburst Arc is likely in a system of two or more galaxies separated by ≲6 kpc in projection. Their interaction may drive star formation and could play a role in the mechanism responsible for the leaking LyC radiation. *Based on observations made with the NASA/ESA Hubble Space Telescope, obtained at the Space Telescope Science Institute, which is operated by the Association of Universities for Research in Astronomy, Inc., under NASA contract NAS 5-26555. These observations are associated with programs GO-15101, GO-15377, GO-15418, and GO-15949.

Keywords: galaxy clusters; strong gravitational lensing; reionization; star formation
Mitigating Internal Instrument Coupling for 21 cm Cosmology. II. A Method Demonstration with the Hydrogen Epoch of Reionization Array

We present a study of internal reflection and cross-coupling systematics in Phase I of the Hydrogen Epoch of Reionization Array (HERA). In a companion paper, we outlined the mathematical formalism for such systematics and presented algorithms for modeling and removing them from the data. In this work, we apply these techniques to data from HERA’s first observing season as a method demonstration. The data show evidence for systematics that, without removal, would hinder a detection of the 21 cm power spectrum for the targeted Epoch of Reionization (EoR) line-of-sight modes in the range 0.2 h -1 Mpc-1 < {k}\parallel < 0.5 h -1 Mpc-1. In particular, we find evidence for nonnegligible amounts of spectral structure in the raw autocorrelations that overlaps with the EoR window and is suggestive of complex instrumental effects. Through systematic modeling on a single night of data, we find we can recover these modes in the power spectrum down to the integrated noise floor, achieving a dynamic range in the EoR window of 106 in power (mK2 units) with respect to the bright galactic foreground signal. Future work with deeper integrations will help determine whether these systematics can continue to be mitigated down to EoR levels. For future observing seasons, HERA will have upgraded analog and digital hardware to better control these systematics in the field.

Keywords: reionization; cosmology; astronomy data analysis
The Impact of Inclination-dependent Attenuation on Ultraviolet Star Formation Rate Tracers

We examine and quantify how hybrid (e.g., UV+IR) star formation rate (SFR) estimators and the A FUV-β relation depend on inclination for disk-dominated galaxies using spectral energy distribution modeling that utilizes the inclination-dependent attenuation curves described in Doore et al. We perform this analysis on a sample of 133 disk-dominated galaxies from the CANDELS fields and 18 disk galaxies from the Spitzer Infrared Nearby Galaxies Survey and Key Insights on Nearby Galaxies: A Far-Infrared Survey with Herschel samples. We find that both the hybrid SFR estimators and the A FUV-β relation present clear dependencies on inclination. To quantify this dependence in the hybrid SFR estimators, we derive an inclination and a far-UV-near-IR color-dependent parametric relation for converting observed UV and IR luminosities into SFRs. For the A FUV-β relation, we introduce an inclination-dependent component that accounts for the majority of the inclination dependence with the scatter of the relation increasing with inclination. We then compare both of these inclination-dependent relations to similar inclination-independent relations found in the literature. From this comparison, we find that the UV+IR correction factor and A FUV for our hybrid and A FUV-β relations, respectively, result in a reduction in the residual scatter of our sample by approximately a factor of 2. Therefore, we demonstrate that inclination must be considered in hybrid SFR estimators and the A FUV-β relation to produce more accurate SFR estimates in disk-dominated galaxies.

Keywords: disk galaxies; extragalactic astronomy; galaxy properties; star formation; spectral energy distribution
Habitability and Biosignatures of Hycean Worlds

We investigate a new class of habitable planets composed of water-rich interiors with massive oceans underlying H2-rich atmospheres, referred to here as Hycean worlds. With densities between those of rocky super-Earths and more extended mini-Neptunes, Hycean planets can be optimal candidates in the search for exoplanetary habitability and may be abundant in the exoplanet population. We investigate the bulk properties (masses, radii, and temperatures), potential for habitability, and observable biosignatures of Hycean planets. We show that Hycean planets can be significantly larger compared to previous considerations for habitable planets, with radii as large as 2.6 R⊕ (2.3 R⊕) for a mass of 10 M⊕ (5 M⊕). We construct the Hycean habitable zone (HZ), considering stellar hosts from late M to Sun-like stars, and find it to be significantly wider than the terrestrial-like HZ. While the inner boundary of the Hycean HZ corresponds to equilibrium temperatures as high as ~500 K for late M dwarfs, the outer boundary is unrestricted to arbitrarily large orbital separations. Our investigations include tidally locked "Dark Hycean" worlds that permit habitable conditions only on their permanent nightsides and "Cold Hycean" worlds that see negligible irradiation. Finally, we investigate the observability of possible biosignatures in Hycean atmospheres. We find that a number of trace terrestrial biomarkers that may be expected to be present in Hycean atmospheres would be readily detectable using modest observing time with the James Webb Space Telescope (JWST). We identify a sizable sample of nearby potential Hycean planets that can be ideal targets for such observations in search of exoplanetary biosignatures.

Keywords: exoplanets; habitable planets; exoplanet atmospheres; radiative transfer; planetary interior; biosignatures; transmission spectroscopy
The Ionization and Dynamics of the Makani Galactic Wind

The Makani galaxy hosts the poster child of a galactic wind on scales of the circumgalactic medium. It consists of a two-episode wind in which the slow, outer wind originated 400 Myr ago (Episode I; R I = 20 - 50 kpc) and the fast, inner wind is 7 Myr old (Episode II; R II = 0 - 20 kpc). While this wind contains ionized, neutral, and molecular gas, the physical state and mass of the most extended phase-the warm, ionized gas-are unknown. Here we present Keck optical spectra of the Makani outflow. These allow us to detect hydrogen lines out to r = 30-40 kpc and thus constrain the mass, momentum, and energy in the wind. Many collisionally excited lines are detected throughout the wind, and their line ratios are consistent with 200-400 km s-1 shocks that power the ionized gas, with v shock = σ wind. Combining shock models, density-sensitive line ratios, and mass and velocity measurements, we estimate that the ionized mass and outflow rate in the Episode II wind could be as high as those of the molecular gas: ${M}_{\mathrm{II}}^{{\rm{H}}{\rm\small{II}}}\sim {M}_{\mathrm{II}}^{{{\rm{H}}}_{2}}=(1-2)\times {10}^{9}\,{M}_{\odot }$ and ${dM}/{{dt}}_{\mathrm{II}}^{{\rm{H}}{\rm\small{II}}}\sim {dM}/{{dt}}_{\mathrm{II}}^{{{\rm{H}}}_{2}}=170-250\,{M}_{\odot }$ yr-1. The outer wind has slowed, so that ${dM}/{{dt}}_{{\rm{I}}}^{{\rm{H}}{\rm\small{II}}}\sim 10\,{M}_{\odot }$ yr-1, but it contains more ionized gas, ${M}_{{\rm{I}}}^{{\rm{H}}{\rm\small{II}}}=5\times {10}^{9}$ M ⊙. The momentum and energy in the recent Episode II wind imply a momentum-driven flow (p "boost" ~7) driven by the hot ejecta and radiation pressure from the Eddington-limited, compact starburst. Much of the energy and momentum in the older Episode I wind may reside in a hotter phase, or lie further into the circumgalactic medium.

Keywords: galactic winds; stellar feedback; starburst galaxies; circumgalactic medium; shocks
Completing the Census of AGN in GOODS-S/HUDF: New Ultradeep Radio Imaging and Predictions for JWST

A global understanding of active galactic nuclei (AGN) and their host galaxies hinges on completing a census of AGN activity without selection biases down to the low-luminosity regime. Toward that goal, we identify AGN within faint radio populations at cosmic noon selected from new ultradeep, high-resolution imaging from the Karl G. Jansky Very Large Array at 6 and 3 GHz. These radio data are spatially coincident with the ultradeep legacy surveys in the GOODS-S/HUDF region, particularly the unparalleled Chandra 7 Ms X-ray imaging. Combined, these data sets provide a unique basis for a thorough census of AGN, allowing simultaneous identification via (1) high X-ray luminosity, (2) hard X-ray spectra, (3) excess X-ray relative to 6 GHz, (4) mid-IR colors, (5) SED fitting, (6) radio excess via the radio-infrared relation, (7) flat radio spectra via multiband radio, and (8) optical spectroscopy. We uncover AGN in fully half our faint radio sample, indicating a source density of one AGN arcmin-2, with a similar number of radio-undetected AGN identified via X-ray over the same area. Our radio-detected AGN are majority radio-quiet, with radio emission consistent with being powered predominantly by star formation. Nevertheless, we find AGN radio signatures in our sample: ∼12% with radio excess indicating radio-loud activity, and ∼16% of radio-quiet AGN candidates with flat or inverted radio spectra. The latter is a lower limit, pending our upcoming deeper 3 GHz survey. Finally, despite these extensive data sets, this work is likely still missing heavily obscured AGN. We discuss in detail this elusive population and the prospects for completing our AGN census with James Webb Space Telescope/MIRI.

Keywords: active galactic nuclei; radio galaxies; radio continuum emission; high-redshift galaxies
Prospects for Constraining Interacting Dark Energy Models with 21 cm Intensity Mapping Experiments

We forecast constraints on cosmological parameters in the interacting dark energy models using the mock data generated for neutral hydrogen intensity mapping (IM) experiments. In this work, we only consider the interacting dark energy models with energy transfer rate Q = βHρc and take BINGO, FAST, SKA1-MID, and Tianlai as typical examples of the 21 cm IM experiments. We find that the Tianlai cylinder array will play an important role in constraining the interacting dark energy model. Assuming perfect foreground removal and calibration and using the Tianlai-alone data, we obtain σ(H0) = 0.19 km s-1 Mpc-1, σ(Ωm) = 0.0033, and σ(σ8) = 0.0033 in the IΛCDM model, which are much better than the results of Planck+optical BAO (i.e., optical galaxy surveys). However, the Tianlai-alone data cannot provide a very tight constraint on the coupling parameter β compared with Planck+optical BAO, while the Planck+Tianlai data can give a rather tight constraint of σ(β) = 0.00023 due to the parameter degeneracies being well broken by the data combination. In the IwCDM model, we obtain σ(β) = 0.00079 and σ(w) = 0.013 from Planck+Tianlai. In addition, we also make a detailed comparison among BINGO, FAST, SKA1-MID, and Tianlai in constraining the interacting dark energy models. We show that future 21 cm IM experiments will provide a useful tool for exploring the nature of dark energy and play a significant role in measuring the coupling between dark energy and dark matter.

Keywords: h i line emission; dark energy; cosmological parameters; cosmology
TOI-677b: A Warm Jupiter (P = 11.2 days) on an Eccentric Orbit Transiting a Late F-type Star

We report the discovery of TOI-677 b, first identified as a candidate in light curves obtained within Sectors 9 and 10 of the Transiting Exoplanet Survey Satellite (TESS) mission and confirmed with radial velocities. TOI-677 b has a mass of ${\text{}}{M}_{{\text{}}p} = ${1.236}_{-0.067}^{+0.069} ${\text{}}{M}_{{\rm{J}}}, a radius of ${\text{}}{R}_{{\text{}}P} = $1.170\pm 0.03 ${\text{}}{R}_{{\rm{J}}}, and orbits its bright host star (V = 9.8 mag) with an orbital period of $11.23660\pm 0.00011 d, on an eccentric orbit with $e=0.435\pm 0.024 . The host star has a mass of ${\text{}}{M}_{\star } = $1.181\pm 0.058 ${\text{}}{M}_{\odot }, a radius of ${\text{}}{R}_{\star } = ${1.28}_{-0.03}^{+0.03} ${\text{}}{R}_{\odot }, an age of ${2.92}_{-0.73}^{+0.80} Gyr and solar metallicity, properties consistent with a main-sequence late-F star with ${T}_{\mathrm{eff}}=6295\pm 77 K. We find evidence in the radial velocity measurements of a secondary long-term signal, which could be due to an outer companion. The TOI-677 b system is a well-suited target for Rossiter-Mclaughlin observations that can constrain migration mechanisms of close-in giant planets.

Keywords: exoplanets; extrasolar gaseous giant planets; exoplanet astronomy; transit photometry; radial velocity; planet hosting stars
Mapping the Thermal Condensation of Diffuse H I in the North Celestial Pole Loop

The North Celestial Pole Loop (NCPL) provides a unique laboratory for studying the early stages of star formation, in particular the condensation of the neutral interstellar medium (ISM). Understanding the physical properties that control the evolution of its contents is key to uncovering the origin of the NCPL. Archival data from the NCPL region of the GHIGLS 21 cm line survey (9.'4) are used to map its multiphase content with ROHSA, a Gaussian decomposition tool that includes spatial regularization. Column density and mass fraction maps of each phase were extracted along with their uncertainties. Archival data from the DHIGLS 21 cm (1') survey are used to further probe the multiphase content of the NCPL. We have identified four spatially (and dynamically) coherent components in the NCPL, one of which is a remarkably well-defined arch moving at about 14 km s-1 away from us that could be a relic of the large-scale organized dynamical process at the origin of the phase transition. The cold and lukewarm phases together dominate the mass content of the neutral gas along the loop. Using absorption measurements, we find that the cold phase exhibits slightly supersonic turbulence.

Keywords: interstellar phases; interstellar medium; cold neutral medium; h i line emission
Modeling the Accretion Disk around the High-mass Protostar GGD 27-MM1

Recent high angular resolution (≃40 mas) ALMA observations at 1.14 mm resolve a compact (R ≃ 200 au), flattened dust structure perpendicular to the HH 80-81 jet emanating from the GGD 27-MM1 high-mass protostar, making it a robust candidate for a true accretion disk. The jet-disk system (HH 80-81/GGD 27-MM1) resembles those found in association with low- and intermediate-mass protostars. We present radiative transfer models that fit the 1.14 mm ALMA dust image of this disk, which allow us to obtain its physical parameters and predict its density and temperature structure. Our results indicate that this accretion disk is compact (R disk ≃ 170 au) and massive (≃5 M ⊙), at about 20% of the stellar mass of ≃20 M ⊙. We estimate the total dynamical mass of the star-disk system from the molecular line emission, finding a range between 21 and 30 M ⊙, which is consistent with our model. We fit the density and temperature structures found by our model with power-law functions. These results suggest that accretion disks around massive stars are more massive and hotter than their low-mass siblings, but they still are quite stable. We also compare the temperature distribution in the GGD 27-MM1 disk with that found in low- and intermediate-mass stars and discuss possible implications for the water snow line. We have also carried out a study of the distance based on Gaia DR2 data and the population of young stellar objects in this region and from the extinction maps. We conclude that the source distance is within 1.2 and 1.4 kpc, closer than what was derived in previous studies (1.7 kpc).

Keywords: star formation; massive stars; protoplanetary disks
Architecture of Planetary Systems Predicted from Protoplanetary Disks Observed with ALMA. II. Evolution Outcomes and Dynamical Stability

Recent ALMA observations on disk substructures suggest the presence of embedded protoplanets in a large number of disks. The primordial configurations of these planetary systems can be deduced from the morphology of the disk substructure and serve as initial conditions for numerical investigation of their future evolution. Starting from the initial configurations of 12 multiplanetary systems deduced from ALMA disks, we carried out two-stage N-body simulation to investigate the evolution of the planetary systems at the disk stage, as well as the long-term orbital stability after the disk dispersal. At the disk stage, our simulation includes both the orbital migration and pebble/gas accretion effects. We found that a variety of planetary systems are produced and can be categorized into distant giant planets, Jupiter-like planets, Neptune-like planets, and distant small planets. We found that the disk-stage evolution and the final configurations are sensitive to both the initial mass assignments and viscosity. After the disk stage, we implement only mutual gravity between star and planets and introduce stochastic perturbative forces. All systems are integrated for up to 10 Gyr to test their orbital stability. Most planetary systems are found to be stable for at least 10 Gyr, with perturbative force in a reasonable range. Our result implies that a strong perturbation source such as stellar flybys is required to drive the planetary system unstable. We discuss the implications of our results on both the disk and planet observation, which may be confirmed by the next-generation telescopes such as JWST and ngVLA.

Keywords: protoplanetary disks; exoplanet formation; exoplanet migration
Reading between the (Spectral) Lines: Magellan/IMACS Spectroscopy of the Ultrafaint Dwarf Galaxies Eridanus IV and Centaurus I

We present a spectroscopic analysis of Eridanus IV (Eri IV) and Centaurus I (Cen I), two ultrafaint dwarf galaxies of the Milky Way. Using IMACS/Magellan spectroscopy, we identify 28 member stars of Eri IV and 34 member stars of Cen I. For Eri IV, we measure a systemic velocity of ${v}_{\mathrm{sys}}=-{31.5}_{-1.2}^{+1.3}\ \mathrm{km}\,{{\rm{s}}}^{-1}$ , and velocity dispersion ${\sigma }_{v}={6.1}_{-0.9}^{+1.2}\ \mathrm{km}\,{{\rm{s}}}^{-1}$ . Additionally, we measure the metallicities of 16 member stars of Eri IV. We find a metallicity of $[\mathrm{Fe}/{\rm{H}}]=-{2.87}_{-0.07}^{+0.08}$ , and resolve a dispersion of σ [Fe/H]=0.20 ± 0.09. The mean metallicity is marginally lower than all other known ultrafaint dwarf galaxies, making it one of the most metal-poor galaxies discovered thus far. Eri IV also has a somewhat unusual right-skewed metallicity distribution. For Cen I, we find a velocity v sys = 44.9 ± 0.8 km s‑1, and velocity dispersion ${\sigma }_{v}={4.2}_{-0.5}^{+0.6}\ \mathrm{km}\,{{\rm{s}}}^{-1}$ . We measure the metallicities of 27 member stars of Cen I, and find a mean metallicity [Fe/H] = ‑2.57 ± 0.08, and metallicity dispersion ${\sigma }_{[\mathrm{Fe}/{\rm{H}}]}={0.38}_{-0.05}^{+0.07}$ . We calculate the systemic proper motion, orbit, and the astrophysical J-factor for each system, the latter of which indicates that Eri IV is a good target for indirect dark matter detection. We also find no strong evidence for tidal stripping of Cen I or Eri IV. Overall, our measurements confirm that Eri IV and Cen I are dark-matter-dominated galaxies with properties largely consistent with other known ultrafaint dwarf galaxies. The low metallicity, right-skewed metallicity distribution, and high J-factor make Eri IV an especially interesting candidate for further follow-up.

Keywords: dwarf galaxies; local group; spectroscopy