Search Publications
Three-component Kinematics of Multiple Stellar Populations in Globular Clusters with Gaia and VLT
Milone, A. P.; Cordoni, G.; Marino, A. F. +5 more
The internal dynamics of multiple stellar populations in globular clusters (GCs) provides unique constraints on the physical processes responsible for their formation. Specifically, the present-day kinematics of cluster stars, such as rotation and velocity dispersion, could be related to the initial configuration of the system. In recent work, we …
Two Directly Imaged, Wide-orbit Giant Planets around the Young, Solar Analog TYC 8998-760-1
Ginski, Christian; Kenworthy, Matthew A.; Mamajek, Eric E. +9 more
Even though tens of directly imaged companions have been discovered in the past decades, the number of directly confirmed multiplanet systems is still small. Dynamical analysis of these systems imposes important constraints on formation mechanisms of these wide-orbit companions. As part of the Young Suns Exoplanet Survey we report the detection of…
New Conductive Opacities for White Dwarf Envelopes
Blouin, Simon; Saumon, Didier; Shaffer, Nathaniel R. +1 more
Thanks to their continuous cooling and relative simplicity, white dwarf stars are routinely used to measure the ages of stellar populations. The usefulness of white dwarfs as cosmochronometers depends on the availability of accurate cooling models. A key ingredient of those models is conductive opacities, which largely govern the cooling rate. In …
The Galaxy "Missing Dark Matter" NGC 1052-DF4 is Undergoing Tidal Disruption
Trujillo, Ignacio; Borlaff, Alejandro S.; Monelli, Matteo +4 more
The existence of long-lived galaxies lacking dark matter represents a challenge to our understanding of how galaxies form. Here, we present evidence that explains the lack of dark matter in one such galaxy: NGC 1052-DF4. Deep optical imaging of the system has detected tidal tails in this object caused by its interaction with its neighboring galaxy…
The Red Supergiant Binary Fraction of the Large Magellanic Cloud
Drout, Maria R.; Massey, Philip; Levesque, Emily M. +2 more
The binary fraction of unevolved massive stars is thought to be 70%-100% but there are few observational constraints on the binary fraction of the evolved version of a subset of these stars, the red supergiants (RSGs). Here we identify a complete sample of RSGs in the Large Magellanic Cloud (LMC) using new spectroscopic observations and archival U…
Varstrometry for Off-nucleus and Dual Subkiloparsec AGN (VODKA): Methodology and Initial Results with Gaia DR2
Shen, Yue; Hwang, Hsiang-Chih; Liu, Xin +1 more
Gaia’s precision astrometry allows systematic identification of optically selected subkiloparsec dual active galactic nuclei (AGNs), off-nucleus AGNs, and small-scale lensed quasars by “varstrometry”—where variability-induced astrometric jitter, I.e., temporal displacements of photocenter in unresolved sources, can be reasonably well detected or c…
Three Lyα Emitting Galaxies within a Quasar Proximity Zone at z ∼ 5.8
Ellis, Richard S.; Bosman, Sarah E. I.; Meyer, Romain A. +3 more
Quasar proximity zones at $z\gt 5.5$ correspond to overdense and overionized environments. Galaxies found inside proximity zones can therefore display features that would otherwise be masked by absorption in the intergalactic medium. We demonstrate the utility of this quasar-galaxy synergy by reporting the discovery of the first three "proximate L…
The Strength of the Dynamical Spiral Perturbation in the Galactic Disk
Hogg, David W.; Rix, Hans-Walter; Buck, Tobias +4 more
The mean Galactocentric radial velocities $\langle {v}_{R}\rangle (R,\varphi )$ of luminous red giant stars within the midplane of the Milky Way reveal a spiral signature, which could plausibly reflect the response to a nonaxisymmetric perturbation of the gravitational potential in the Galactic disk. We apply a simple steady-state toy model of a l…
Detailed Abundances in the Ultra-faint Magellanic Satellites Carina II and III
Bechtol, K.; Allam, S.; Gruendl, R. A. +14 more
We present the first detailed elemental abundances in the ultra-faint Magellanic satellite galaxies Carina II (Car II) and Carina III (Car III). With high-resolution Magellan/MIKE spectroscopy, we determined the abundances of nine stars in Car II, including the first abundances of an RR Lyrae star in an ultra-faint dwarf galaxy (UFD), and two star…
The MOSDEF Survey: Kinematic and Structural Evolution of Star-forming Galaxies at 1.4 ≤ z ≤ 3.8
Barro, Guillermo; Übler, Hannah; Siana, Brian +15 more
We present ionized gas kinematics for 681 galaxies at $z\sim 1.4\mbox{--}3.8$ from the MOSFIRE Deep Evolution Field survey, measured using models that account for random galaxy-slit misalignments together with structural parameters derived from CANDELS Hubble Space Telescope (HST) imaging. Kinematics and sizes are used to derive dynamical masses. …