Search Publications
Dynamical Confirmation of a Black Hole in MAXI J1820+070
Armas Padilla, M.; Jiménez-Ibarra, F.; Muñoz-Darias, T. +4 more
We present time-resolved 10.4 m Gran Telescopio Canarias and 4.2 m William Herschel Telescope intermediate resolution spectroscopy of the X-ray transient MAXI J1820+070 (=ASASSN-18ey) obtained during its decline to the quiescent state. Cross-correlation of the 21 individual spectra against late-type templates reveals a sinusoidal velocity modulati…
The Inside-out Growth of the Galactic Disk
Ting, Yuan-Sen; Rix, Hans-Walter; Ness, Melissa +2 more
We quantify the inside-out growth of the Milky Way’s low-α stellar disk, modeling the ages, metallicities, and Galactocentric radii of APOGEE red clump stars with 6 kpc < R < 13 kpc. The current stellar distribution differs significantly from that expected from the star formation history due to the redistribution of stars through radial orbi…
Proper Motions of Milky Way Ultra-faint Satellites with Gaia DR2 × DES DR1
Li, Ting S.; Pace, Andrew B.
We present a new, probabilistic method for determining the systemic proper motions of Milky Way (MW) ultra-faint satellites in the Dark Energy Survey (DES). We utilize the superb photometry from the first public data release (DR1) of the DES to select candidate members and cross-match them with the proper motions from the Gaia DR2. We model the ca…
Systematic Variations of CO Gas Abundance with Radius in Gas-rich Protoplanetary Disks
Zhang, Ke; Bergin, Edwin A.; Krijt, Sebastiaan +2 more
CO is the most widely used gas tracer of protoplanetary disks. Its abundance is usually assumed to be an interstellar ratio throughout the warm molecular layer of the disk. But recent observations of low CO gas abundance in many protoplanetary disks challenge our understanding of physical and chemical evolutions in disks. Here we investigate the C…
Mapping the Magnetic Interstellar Medium in Three Dimensions over the Full Sky with Neutral Hydrogen
Hensley, Brandon S.; Clark, S. E.
Recent analyses of 21 cm neutral hydrogen (H I) emission have demonstrated that H I gas is organized into linear filamentary structures that are preferentially aligned with the local magnetic field, and that the coherence of these structures in velocity space traces line-of-sight magnetic field tangling. On this basis, we introduce a paradigm for …
HAWC+/SOFIA Multiwavelength Polarimetric Observations of OMC-1
Morris, Mark R.; Staguhn, Johannes; Ward-Thompson, Derek +36 more
We report new polarimetric and photometric maps of the massive star-forming region OMC-1 using the HAWC+ instrument on the Stratospheric Observatory for Infrared Astronomy. We present continuum polarimetric and photometric measurements of this region at 53, 89, 154, and 214 µm at angular resolutions of 5″, 8″, 14″, and 19″ for the four bands…
Kiloparsec Scale Properties of Star Formation Driven Outflows at z ∼ 2.3 in the SINS/zC-SINF AO Survey
Lutz, D.; Wuyts, S.; Förster Schreiber, N. M. +19 more
We investigate the relationship between star formation activity and outflow properties on kiloparsec scales in a sample of 28 star-forming galaxies at z ∼ 2-2.6, using adaptive optics assisted integral field observations from SINFONI on the Very Large Telescope. The narrow and broad components of the Hα emission are used to simultaneously determin…
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 …