Search Publications
Kinematics of Circumgalactic Gas: Feeding Galaxies and Feedback
Martin, Crystal L.; Kacprzak, Glenn G.; Churchill, Christopher W. +1 more
We present observations of 50 pairs of redshift z ≈ 0.2 star-forming galaxies and background quasars. These sightlines probe the circumgalactic medium (CGM) out to half the virial radius, and we describe the circumgalactic gas kinematics relative to the reference frame defined by the galactic disks. We detect halo gas in Mg II absorption, measure …
Implications of the Warm Corona and Relativistic Reflection Models for the Soft Excess in Mrk 509
Steiner, James F.; Wilms, Jörn; Ricci, Claudio +15 more
We present the analysis of the first Nuclear Spectroscopic Telescope Array observations (∼220 ks), simultaneous with the last Suzaku observations (∼50 ks), of the active galactic nucleus of the bright Seyfert 1 galaxy Mrk 509. The time-averaged spectrum in the 1-79 keV X-ray band is dominated by a power-law continuum (Γ ∼ 1.8-1.9), a strong soft e…
Supermassive Black Hole Binary Candidates from the Pan-STARRS1 Medium Deep Survey
Tonry, J.; Huber, M. E.; Waters, C. +9 more
We present a systematic search for periodically varying quasar and supermassive black hole binary (SMBHB) candidates in the Pan-STARRS1 Medium Deep Survey (MDS). From ∼9000 color-selected quasars in an ∼50 °2 sky area, we initially identify 26 candidates with more than 1.5 cycles of variation. We extend the baseline of observations via …
Galactic Winds in Low-mass Galaxies
Skillman, Evan D.; van Zee, Liese; McQuinn, Kristen. B. W.
Stellar-feedback-driven outflows are predicted to play a fundamental role in the baryon cycle of low-mass galaxies. However, observational constraints of winds in nearby dwarf galaxies are limited, as outflows are transient, intrinsically low surface brightness features and thus difficult to detect. Using deep Hα observations, we search for winds …
The Cumulative Mass Profile of the Milky Way as Determined by Globular Cluster Kinematics from Gaia DR2
Eadie, Gwendolyn; Jurić, Mario
We present new mass estimates and cumulative mass profiles (CMPs) with Bayesian credible regions for the Milky Way (MW) Galaxy, given the kinematic data of globular clusters (GCs) as provided by (1) the Gaia DR2 collaboration and the HSTPROMO team, and (2) the new catalog in Vasiliev (2019). We use GCs beyond 15 kpc to estimate the CMP of the MW, …
The M101 Satellite Luminosity Function and the Halo-Halo Scatter among Local Volume Hosts
Zaritsky, D.; Crnojević, D.; Mutlu-Pakdil, B. +4 more
We have obtained deep Hubble Space Telescope (HST) imaging of 19 dwarf galaxy candidates in the vicinity of M101. Advanced Camera for Surveys HST photometry for two of these objects showed resolved stellar populations and tip of the red giant branch derived distances (D ∼ 7 Mpc) consistent with M101 group membership. The remaining 17 were found to…
The Discovery of a Gravitationally Lensed Quasar at z = 6.51
Hennawi, Joseph F.; Fan, Xiaohui; McGreer, Ian D. +17 more
Strong gravitational lensing provides a powerful probe of the physical properties of quasars and their host galaxies. A high fraction of the most luminous high-redshift quasars was predicted to be lensed due to magnification bias. However, no multiple imaged quasar was found at z > 5 in previous surveys. We report the discovery of J043947.08+16…
No Clear, Direct Evidence for Multiple Protoplanets Orbiting LkCa 15: LkCa 15 bcd are Likely Inner Disk Signals
Henning, Thomas; Currie, Thayne; Dong, Ruobing +30 more
Two studies utilizing sparse aperture-masking (SAM) interferometry and H α differential imaging have reported multiple Jovian companions around the young solar-mass star, LkCa 15 (LkCa 15 bcd): the first claimed direct detection of infant, newly formed planets (“protoplanets”). We present new near-infrared direct imaging/spectroscopy f…
Resolved UV and [C II] Structures of Luminous Galaxies within the Epoch of Reionization
Schaerer, D.; Mobasher, B.; Ferrara, A. +7 more
We present new deep ALMA and Hubble Space Telescope (HST)/WFC3 observations of MASOSA and VR7, two luminous Lyα emitters (LAEs) at z = 6.5, for which the UV continuum levels differ by a factor of four. No IR dust continuum emission is detected in either, indicating little amounts of obscured star formation and/or high dust temperatures. MASOSA, wi…
Tidal Interactions between Binary Stars Can Drive Lithium Production in Low-mass Red Giants
Hogg, David W.; Casey, Andrew R.; Rix, Hans-Walter +10 more
Theoretical models of stellar evolution predict that most of the lithium inside a star is destroyed as the star becomes a red giant. However, observations reveal that about 1% of red giants are peculiarly rich in lithium, often exceeding the amount in the interstellar medium or predicted from the big bang. With only about 150 lithium-rich giants d…