Search Publications
Understanding Dual Active Galactic Nucleus Activation in the nearby Universe
Koss, Michael; Veilleux, Sylvain; Mushotzky, Richard +3 more
We study the fraction of dual active galactic nuclei (AGNs) in a sample of 167 nearby (z < 0.05), moderate-luminosity, ultra-hard X-ray-selected AGNs from the all-sky Swift Burst Alert Telescope (BAT) survey. Combining new Chandra and Gemini observations together with optical and X-ray observations, we find that the dual AGN frequency at scales…
Large-amplitude Variations of an L/T Transition Brown Dwarf: Multi-wavelength Observations of Patchy, High-contrast Cloud Features
Marley, Mark; Radigan, Jacqueline; Saumon, Didier +3 more
We present multiple-epoch photometric monitoring in the J, H, and Ks bands of the T1.5 dwarf 2MASS J21392676+0220226 (2M2139), revealing persistent, periodic (P = 7.721 ± 0.005 hr) variability with a peak-to-peak amplitude as high as 26% in the J band. The light curve shape varies on a timescale of days, suggesting that evolving atmosph…
Herschel Far-infrared and Submillimeter Photometry for the KINGFISH Sample of nearby Galaxies
Helou, G.; Roussel, H.; Murphy, E. J. +39 more
New far-infrared and submillimeter photometry from the Herschel Space Observatory is presented for 61 nearby galaxies from the Key Insights on Nearby Galaxies: A Far-Infrared Survey with Herschel (KINGFISH) sample. The spatially integrated fluxes are largely consistent with expectations based on Spitzer far-infrared photometry and extrapolations t…
A Radio-selected Sample of Gamma-Ray Burst Afterglows
Chandra, Poonam; Frail, Dale A.
We present a catalog of radio afterglow observations of gamma-ray bursts (GRBs) over a 14 year period from 1997 to 2011. Our sample of 304 afterglows consists of 2995 flux density measurements (including upper limits) at frequencies between 0.6 GHz and 660 GHz, with the majority of data taken at 8.5 GHz frequency band (1539 measurements). We use t…
GOODS-Herschel Measurements of the Dust Attenuation of Typical Star-forming Galaxies at High Redshift: Observations of Ultraviolet-selected Galaxies at z ~ 2
Magnelli, B.; Altieri, B.; Aussel, H. +20 more
We take advantage of the sensitivity and resolution of the Herschel Space Observatory at 100 and 160 µm to directly image the thermal dust emission and investigate the infrared luminosities (L IR) and dust obscuration of typical star-forming (L*) galaxies at high redshift. Our sample consists of 146 UV-selected galaxies with spect…
The Epoch of Disk Settling: z ~ 1 to Now
Weiner, Benjamin J.; Gardner, Jonathan P.; Faber, S. M. +11 more
We present evidence from a sample of 544 galaxies from the DEEP2 Survey for evolution of the internal kinematics of blue galaxies with stellar masses ranging 8.0 < log M *(M ⊙) < 10.7 over 0.2 < z < 1.2. DEEP2 provides galaxy spectra and Hubble imaging from which we measure emission-line kinematics and galaxy incl…
The Type IIb Supernova 2011dh from a Supergiant Progenitor
Nomoto, Ken'ichi; Fraser, Morgan; Sollerman, Jesper +10 more
A set of hydrodynamical models based on stellar evolutionary progenitors is used to study the nature of SN 2011dh. Our modeling suggests that a large progenitor star—with R ~ 200 R ⊙—is needed to reproduce the early light curve (LC) of SN 2011dh. This is consistent with the suggestion that the yellow super-giant star detected at the loc…
Evidence for a Clumpy, Rotating Gas Disk in a Submillimeter Galaxy at z = 4
Daddi, E.; Walter, F.; Riechers, D. +4 more
We present Karl G. Jansky Very Large Array observations of the CO(2-1) emission in the z = 4.05 submillimeter galaxy (SMG) GN20. These high-resolution data allow us to image the molecular gas at 1.3 kpc resolution just 1.6 Gyr after the big bang. The data reveal a clumpy, extended gas reservoir, 14 ± 4 kpc in diameter, in unprecedented detail. A d…
A Large Population of Massive Compact Post-starburst Galaxies at z > 1: Implications for the Size Evolution and Quenching Mechanism of Quiescent Galaxies
van Dokkum, Pieter G.; Franx, Marijn; Labbé, Ivo +4 more
We study the growth of the red sequence through the number density and structural evolution of a sample of young and old quiescent galaxies at 0 < z < 2. The galaxies are selected from the NEWFIRM Medium-Band Survey in the Cosmic Evolution Survey field. We find a large population of massive young recently quenched ("post-starburst") galaxies…
Reverberation Mapping Results for Five Seyfert 1 Galaxies
Skowron, J.; Kochanek, C. S.; Peterson, B. M. +40 more
We present the results from a detailed analysis of photometric and spectrophotometric data on five Seyfert 1 galaxies observed as a part of a recent reverberation mapping program. The data were collected at several observatories over a 140 day span beginning in 2010 August and ending in 2011 January. We obtained high sampling-rate light curves for…