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The globular clusters and star formation history of the isolated, quiescent ultra-diffuse galaxy DGSAT I
van Dokkum, Pieter G.; Forbes, Duncan A.; Romanowsky, Aaron J. +6 more
We investigate the isolated, quiescent ultra-diffuse galaxy (UDG) DGSAT I and its globular cluster (GC) system using two orbits of Hubble Space Telescope Advanced Camera for Surveys imaging in the F606W and F814W filters. This is the first study of GCs around a UDG in a low-density environment. DGSAT I was previously found to host an irregular blu…
Diagnosing FU Ori-like Sources: The Parameter Space of Viscously Heated Disks in the Optical and Near-infrared
Herczeg, Gregory J.; Jose, Jessy; Johnstone, Doug +8 more
FU Ori-type objects (FUors) are decades-long outbursts of accretion onto young stars that are strong enough to viscously heat disks so that the disk outshines the central star. We construct models for FUor objects by calculating emission components from a steady-state viscous accretion disk, a passively-heated dusty disk, magnetospheric accretion …
The Orbits of the Main Saturnian Satellites, the Saturnian System Gravity Field, and the Orientation of Saturn's Pole
Jacobson, Robert. A.
Four spacecraft have been sent to investigate the Saturnian system: Pioneer 11, Voyager 1, Voyager 2, and Cassini. By analyzing data acquired with these spacecraft together with Earth-based and Hubble Space Telescope satellite astrometry and Saturnian ring and satellite occultations, we constructed a model for the orientation and precession of Sat…
Kinematic properties of white dwarfs. Galactic orbital parameters and age-velocity dispersion relation
Rebassa-Mansergas, Alberto; Raddi, Roberto; Torres, Santiago +9 more
Context. Kinematic and chemical tagging of stellar populations have both revealed much information on the past and recent history of the Milky Way, including its formation history, merger events, and mixing of populations across the Galactic disk and halo.
Aims: We present the first detailed 3D kinematic analysis of a sample of 3133 white dwa…
AGN Selection Methods Have Profound Impacts on the Distributions of Host-galaxy Properties
Giavalisco, Mauro; Kirkpatrick, Allison; Ji, Zhiyuan +4 more
We present a comparative study of X-ray and IR active galactic nuclei (AGNs) at z ≈ 2 to highlight the important AGN selection effects on the distributions of host-galaxy properties. Compared with non-AGN star-forming galaxies (SFGs) on the main sequence, X-ray AGNs have similar median star formation (SF) properties, but their incidence (q AG…
Dynamical state of galaxy clusters evaluated from X-ray images
Yuan, Z. S.; Han, J. L.; Wen, Z. L.
X-ray images of galaxy clusters often show disturbed structures that are indications of cluster mergers. To complement our previous work on the dynamical state of 964 clusters observed by Chandra, we process the X-ray images for 1308 clusters from XMM-Newton archival data, together with the images of 22 clusters newly released by Chandra, and we e…
The detailed chemical abundance patterns of accreted halo stars from the optical to infrared
Hawkins, Keith; Lucey, Madeline; Jofré, Paula +3 more
Understanding the assembly of our Galaxy requires us to also characterize the systems that helped build it. In this work, we accomplish this by exploring the chemistry of accreted halo stars from Gaia-Enceladus/Gaia-Sausage (GES) selected in the infrared from the Apache Point Observatory Galactic Evolution Experiment (APOGEE) Data Release 16. We u…
An Atmospheric Retrieval of the Brown Dwarf Gliese 229B
Faherty, Jacqueline K.; Calamari, Emily; Burningham, Ben +6 more
We present results from an atmospheric retrieval analysis of Gl 229B using the Brewster retrieval code. We find the best fit model to be cloud-free, consistent with the T dwarf retrieval work of Line et al.; Zalesky et al. and Gonzales et al. Fundamental parameters (mass, radius, log(L Bol /L Sun), log(g)) determined from our…
The CARMENES search for exoplanets around M dwarfs. Benchmarking the impact of activity in high-precision radial velocity measurements
Amado, P. J.; Caballero, J. A.; Czesla, S. +17 more
Context. Current exoplanet surveys using the radial velocity (RV) technique are targeting M dwarfs because any habitable zone terrestrial-mass planets will induce a high RV and orbit on shorter periods than for more massive stars. One of the main caveats is that M dwarfs show a wide range of activity levels from inactive to very active, which can …
Dark matter in galaxy clusters: Parametric strong-lensing approach
Jullo, Eric; Limousin, Marceau; Beauchesne, Benjamin
We present a parametric strong-lensing analysis of three massive galaxy clusters for which Hubble Space Telescope imaging is available, as well as spectroscopy of multiply imaged systems and galaxy cluster members. Our aim is to probe the inner shape of dark matter haloes, in particular the existence of a core. We adopted the following working hyp…