Search Publications
A New M Dwarf Debris Disk Candidate in a Young Moving Group Discovered with Disk Detective
Kuchner, Marc J.; Gagné, Jonathan; Wisniewski, John P. +14 more
We used the Disk Detective citizen science project and the BANYAN II Bayesian analysis tool to identify a new candidate member of a nearby young association with infrared excess. WISE J080822.18-644357.3, an M5.5-type debris disk system with significant excess at both 12 and 22 µm, is a likely member (∼ 90 % BANYAN II probability) of the ∼45…
Detection of Phosphorus, Sulphur, and Zinc in the Carbon-enhanced Metal-poor Star BD+44 493
Beers, Timothy C.; Placco, Vinicius M.; Roederer, Ian U.
The carbon-enhanced metal-poor star BD+44°493 ([Fe/H] = -3.9) has been proposed as a candidate second-generation star enriched by metals from a single Pop III star. We report the first detections of P and S and the second detection of Zn in any extremely metal-poor carbon-enhanced star, using new spectra of BD+44°493 collected by the Cosmic Origin…
SPT0346-52: Negligible AGN Activity in a Compact, Hyper-starburst Galaxy at z = 5.7
Béthermin, M.; Brandt, W. N.; Murphy, E. J. +20 more
We present Chandra ACIS-S and Australia Telescope Compact Array (ATCA) radio continuum observations of the strongly lensed dusty, star-forming galaxy SPT-S J034640-5204.9 (hereafter SPT0346-52) at z = 5.656. This galaxy has also been observed with ALMA, HST, Spitzer, Herschel, Atacama Pathfinder EXperiment, and the Very Large Telescope. Previous o…
Multi-viewpoint Observations of a Widely distributed Solar Energetic Particle Event: The Role of EUV Waves and White-light Shock Signatures
Hillaris, A.; Patsourakos, S.; Nindos, A. +4 more
On 2012 March 7, two large eruptive events occurred in the same active region within 1 hr from each other. Each consisted of an X-class flare, a coronal mass ejection (CME), an extreme-ultraviolet (EUV) wave, and a shock wave. The eruptions gave rise to a major solar energetic particle (SEP) event observed at widely separated (∼120°) points in the…
PICS: Simulations of Strong Gravitational Lensing in Galaxy Clusters
Florian, Michael K.; Gladders, Michael D.; Li, Nan +5 more
Gravitational lensing has become one of the most powerful tools available for investigating the “dark side” of the universe. Cosmological strong gravitational lensing, in particular, probes the properties of the dense cores of dark matter halos over decades in mass and offers the opportunity to study the distant universe at flux levels and spatial…
IROCKS: Spatially Resolved Kinematics of z ∼ 1 Star-forming Galaxies
Juneau, Stéphanie; Salim, Samir; Armus, Lee +4 more
We present results from the Intermediate Redshift OSIRIS Chemo-Kinematic Survey (IROCKS) for sixteen z ∼ 1 and one z ∼ 1.4 star-forming galaxies. All galaxies were observed with OSIRIS with the laser guide star adaptive optics system at Keck Observatory. We use rest-frame nebular Hα emission lines to trace morphologies and kinematics of ionized ga…
The Peculiar Debris Disk of HD 111520 as Resolved by the Gemini Planet Imager
Matthews, Brenda C.; Duchêne, Gaspard; Oppenheimer, Rebecca +33 more
Using the Gemini Planet Imager, we have resolved the circumstellar debris disk around HD 111520 at a projected range of ∼30-100 AU in both total and polarized H-band intensity. The disk is seen edge-on at a position angle of 165° along the spine of emission. A slight inclination and asymmetric warp are covariant and alter the interpretation of the…
HST-COS Observations of AGNs. III. Spectral Constraints in the Lyman Continuum from Composite COS/G140L Data
Stevans, Matthew L.; Shull, J. Michael; Danforth, Charles W. +1 more
The rest-frame ultraviolet (UV) spectra of active galactic nuclei (AGNs) are important diagnostics of both accretion disk physics and their contribution to the metagalactic ionizing UV background. Though the mean AGN spectrum is well characterized with composite spectra at wavelengths greater than 912 Å, the shorter-wavelength extreme-UV (EUV) rem…
Absolute Calibration of the Radio Astronomy Flux Density Scale at 22 to 43 GHz Using Planck
López-Caniego, M.; Partridge, B.; Rocha, G. +5 more
The Planck mission detected thousands of extragalactic radio sources at frequencies from 28 to 857 GHz. Planck's calibration is absolute (in the sense that it is based on the satellite’s annual motion around the Sun and the temperature of the cosmic microwave background), and its beams are well characterized at sub-percent levels. Thus, Planck's f…
SHIELD: Neutral Gas Kinematics and Dynamics
McQuinn, Kristen B. W.; Cannon, John M.; Skillman, Evan D. +22 more
We present kinematic analyses of the 12 galaxies in the “Survey of H I in Extremely Low-mass Dwarfs” (SHIELD). We use multi-configuration interferometric observations of the H I 21 cm emission line from the Karl G. Jansky Very Large Array (VLA)22 to produce image cubes at a variety of spatial and spectral resolutions. Both two- and thre…