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Uniform Forward-modeling Analysis of Ultracool Dwarfs. III. Late-M and L Dwarfs in Young Moving Groups, the Pleiades, and the Hyades
Liu, Michael C.; Zhang, Zhoujian; Deacon, Niall R. +5 more
We present a uniform forward-modeling analysis of 90 late-M and L dwarfs in nearby young (~10-200 Myr) moving groups, the Pleiades, and the Hyades using low-resolution (R ≈ 150) near-infrared (0.9-2.4 µm) spectra and the BT-Settl model atmospheres. We derive the objects' effective temperatures, surface gravities, radii, and masses by compari…
Cosmic dipoles of active galactic nuclei at optical and radio wavelengths display much larger amplitudes than the cosmic microwave background dipole
Singal, Ashok K.
Sky distributions of large samples of distant active galactic nuclei (AGNs) have shown dipoles significantly larger than the cosmic microwave background (CMB) dipole. However, a recent Bayesian analysis of the Quaia sample, comprising 1.3 million quasars, has yielded a dipole that seems to be in tandem with the CMB dipole, in contravention of most…
Comparing bulge RR Lyrae stars with bulge giants: Insight from 3D kinematics
Zoccali, M.; Valenti, E.; Contreras Ramos, R. +6 more
Context. The structure and kinematics of the old component of the Galactic bulge are still a matter of debate. It is clear that the bulk of the bulge as traced by red clump stars includes two main components, which are usually identified as the metal-rich and metal-poor components. They have different shapes, kinematics, mean metallicities, and al…
Stellar companions and Jupiter-like planets in young associations
Barbato, D.; D'Orazi, V.; Nascimbeni, V. +9 more
Context. The formation mechanisms of stellar, brown dwarf, and planetary companions, their dependencies on the environment and their interactions with each other are still not well established. Recently, combining high-contrast imaging and space astrometry we found that Jupiter-like (JL) planets are frequent in the β Pic moving group (BPMG) around…
Emergence hour-by-hour of r-process features in the kilonova AT2017gfo
Heintz, Kasper E.; Watson, Darach; Väisänen, Petri +4 more
The spectral features in the optical/near-infrared counterparts of neutron star mergers (kilonovae, KNe) evolve dramatically on hourly timescales. To examine the spectral evolution, we compiled a temporal series that was complete at all observed epochs from 0.5 to 9.4 days of the best optical/near-infrared (NIR) spectra of the gravitational-wave d…
Extended high-ionization [Mg IV] emission tracing widespread shocks in starbursts seen by JWST/NIRSpec
Arribas, Santiago; Perna, Michele; Colina, Luis +6 more
We report the detection of extended (> 0.5-1 kpc) high-ionization [Mg IV] 4.487 µm (80 eV) emission in four local luminous infrared galaxies observed with JWST/NIRSpec. Excluding the nucleus and outflow of the Type 1 active galactic nucleus (AGN) in the sample, we find that the [Mg IV] luminosity is well correlated with that of H recombin…
A hidden population of massive white dwarfs: two spotted K + WD binaries
Lu, Jessica R.; Fulton, Benjamin J.; Kochanek, Christopher S. +10 more
The identification and characterization of massive (≳ 0.8 M⊙) white dwarfs is challenging in part due to their low luminosity. Here, we present two candidate single-lined spectroscopic binaries, Gaia DR3 4014708864481651840 and 5811237403155163520, with K-dwarf primaries and optically dark companions. Both have orbital periods of P ~ 0.…
VODKA-JWST: A 3.8 kpc Dual Quasar at Cosmic Noon in a Powerful Starburst Galaxy with JWST/MIRI Integral Field Unit
Shen, Yue; Veilleux, Sylvain; Zakamska, Nadia L. +12 more
Dual quasars—two active supermassive black holes at galactic scales—represent crucial objects for studying the impact of galaxy mergers and quasar activity on the star formation rate (SFR) within their host galaxies, particularly at cosmic noon when SFR peaks. We present JWST/MIRI mid-infrared integral field spectroscopy of J074922.96+225511.7, a …
WIYN Open Cluster Study. XC. Barium Surface Abundances of Blue Straggler Stars in the Open Clusters NGC 7789 and M67
Schuler, Simon C.; Mathieu, Robert D.; Nine, Andrew C. +1 more
We investigate barium (Ba) abundances in blue straggler stars (BSSs) in two open clusters, NGC 7789 (1.6 Gyr) and M67 (4 Gyr), as signatures of asymptotic-giant-branch (AGB) mass transfer. We combine our findings with previous Ba abundance analyses of NGC 6819 (2.5 Gyr) and NGC 188 (7 Gyr). Out of 35 BSSs studied in NGC 7789, NGC 6819, and M67, 15…
Obscured AGN enhancement in galaxy pairs at cosmic noon: evidence from a probabilistic treatment of photometric redshifts
Kocevski, Dale D.; Rosario, D. J.; Harrison, C. M. +1 more
Observations of the nearby universe reveal an increasing fraction of active galactic nuclei (AGNs) with decreasing projected separation for close galaxy pairs, relative to control galaxies. This implies galaxy interactions play a role in enhancing AGN activity. However, the picture at higher redshift is less established, partly due to limited spec…