Search Publications
SCUBA-2 Ultra Deep Imaging EAO Survey (STUDIES): Faint-end Counts at 450 µm
Goto, Tomotsugu; Smail, Ian; Bunker, Andrew J. +40 more
The SCUBA-2 Ultra Deep Imaging EAO Survey (STUDIES) is a three-year JCMT Large Program aiming to reach the 450 µm confusion limit in the COSMOS-CANDELS region to study a representative sample of the high-redshift far-infrared galaxy population that gives rise to the bulk of the far-infrared background. We present the first-year data from STU…
The State-of-the-art HST Astro-photometric Analysis of the Core of ω Centauri. III. The Main Sequence's Multiple Populations Galore
Anderson, J.; Milone, A. P.; Marino, A. F. +5 more
We take advantage of the exquisite quality of the Hubble Space Telescope 26-filter astro-photometric catalog of the core of ω Cen presented in the first paper of this series and the empirical differential-reddening correction presented in the second paper in order to distill the main sequence into its constituent populations. To this end, we restr…
Variable H13CO+ Emission in the IM Lup Disk: X-Ray Driven Time-dependent Chemistry?
Cleeves, L. Ilsedore; Bergin, Edwin A.; Öberg, Karin I. +3 more
We report the first detection of a substantial brightening event in an isotopologue of a key molecular ion, HCO+, within a protoplanetary disk of a T Tauri star. The H13CO+ J=3-2 rotational transition was observed three times toward IM Lup between 2014 July and 2015 May with the Atacama Large Millimeter/submillimet…
On a New Theoretical Framework for RR Lyrae Stars. II. Mid-infrared Period-Luminosity-Metallicity Relations
Madore, Barry F.; Freedman, Wendy L.; Beaton, Rachael L. +14 more
We present new theoretical period-luminosity-metallicity (PLZ) relations for RR Lyræ stars (RRLs) at Spitzer and WISE wavelengths. The PLZ relations were derived using nonlinear, time-dependent convective hydrodynamical models for a broad range of metal abundances (Z = 0.0001-0.0198). In deriving the light curves, we tested two sets of atmospheric…
The SOFIA Massive (SOMA) Star Formation Survey. I. Overview and First Results
Tanaka, Kei E. I.; Zhang, Yichen; Tan, Jonathan C. +6 more
We present an overview and first results of the Stratospheric Observatory For Infrared Astronomy Massive (SOMA) Star Formation Survey, which is using the FORCAST instrument to image massive protostars from ∼10 to 40 µm. These wavelengths trace thermal emission from warm dust, which in Core Accretion models mainly emerges from the inner regio…
Galactic-scale Feedback Observed in the 3C 298 Quasar Host Galaxy
Armus, Lee; Larkin, James E.; Wright, Shelley A. +3 more
We present high angular resolution multiwavelength data of the 3C 298 radio-loud quasar host galaxy (z = 1.439) taken using the W.M. Keck Observatory OSIRIS integral field spectrograph (IFS) with adaptive optics, the Atacama Large Millimeter/submillimeter Array (ALMA), the Hubble Space Telescope (HST) WFC3, and the Very Large Array (VLA). Extended…
Elongation of Flare Ribbons
Qiu, Jiong; Longcope, Dana W.; Cassak, Paul A. +1 more
We present an analysis of the apparent elongation motion of flare ribbons along the polarity inversion line (PIL), as well as the shear of flare loops in several two-ribbon flares. Flare ribbons and loops spread along the PIL at a speed ranging from a few to a hundred km s-1. The shear measured from conjugate footpoints is consistent wi…
Luminous and Variable Stars in M31 and M33. IV. Luminous Blue Variables, Candidate LBVs, B[e] Supergiants, and the Warm Hypergiants: How to Tell Them Apart
Humphreys, Roberta M.; Gordon, Michael S.; Martin, John C. +2 more
In this series of papers we have presented the results of a spectroscopic survey of luminous stars in the nearby spirals M31 and M33. Here, we present spectroscopy of 132 additional stars. Most have emission-line spectra, including luminous blue variables (LBVs) and candidate LBVs, Fe II emission line stars, the B[e] supergiants, and the warm hype…
Absolute Ages and Distances of 22 GCs Using Monte Carlo Main-sequence Fitting
Chaboyer, Brian; O'Malley, Erin M.; Gilligan, Christina
The recent Gaia Data Release 1 of stellar parallaxes provides ample opportunity to find metal-poor main-sequence stars with precise parallaxes. We select 21 such stars with parallax uncertainties better than σ π /π ≤ 0.10 and accurate abundance determinations suitable for testing metal-poor stellar evolution models and determining the …
The Sirius System and Its Astrophysical Puzzles: Hubble Space Telescope and Ground-based Astrometry
Schaefer, Gail H.; Bond, Howard E.; Burleigh, Matthew R. +11 more
Sirius, the seventh-nearest stellar system, is a visual binary containing the metallic-line A1 V star Sirius A, the brightest star in the sky, orbited in a 50.13 year period by Sirius B, the brightest and nearest white dwarf (WD). Using images obtained over nearly two decades with the Hubble Space Telescope (HST), along with photographic observati…