Search Publications
The Distance to NGC 4993: The Host Galaxy of the Gravitational-wave Event GW170817
Gall, Christa; Hjorth, Jens; Tanvir, Nial R. +6 more
The historic detection of gravitational waves from a binary neutron star merger (GW170817) and its electromagnetic counterpart led to the first accurate (sub-arcsecond) localization of a gravitational-wave event. The transient was found to be ∼10″ from the nucleus of the S0 galaxy NGC 4993. We report here the luminosity distance to this galaxy usi…
Placing the Spotted T Tauri Star LkCa 4 on an HR Diagram
Herczeg, Gregory J.; Jose, Jessy; Liu, Chun-Fan +12 more
Ages and masses of young stars are often estimated by comparing their luminosities and effective temperatures to pre-main-sequence stellar evolution tracks, but magnetic fields and starspots complicate both the observations and evolution. To understand their influence, we study the heavily spotted weak-lined T-Tauri star LkCa 4 by searching for sp…
Calibrating Star Formation in WISE Using Total Infrared Luminosity
Dale, D. A.; Smith, J. -D. T.; Brown, M. J. I. +3 more
We present accurate resolved WISE photometry of galaxies in the combined SINGS and KINGFISH sample. The luminosities in the W3 12 µm and W4 23 µm bands are calibrated to star formation rates (SFRs) derived using the total infrared luminosity, avoiding UV/optical uncertainties due to dust extinction corrections. The W3 relation has a 1σ…
z ∼ 2: An Epoch of Disk Assembly
Trump, Jonathan R.; Weiner, Benjamin J.; Pacifici, Camilla +8 more
We explore the evolution of the internal gas kinematics of star-forming galaxies from the peak of cosmic star formation at z∼ 2 to today. Measurements of galaxy rotation velocity V rot, which quantify ordered motions, and gas velocity dispersion {σ }g, which quantify disordered motions, are adopted from the DEEP2 and SIGMA su…
X-Ray Brightening and UV Fading of Tidal Disruption Event ASASSN-15oi
Cenko, S. B.; Arcavi, I.; Gezari, S.
We present late-time observations by Swift and XMM-Newton of the tidal disruption event (TDE) ASASSN-15oi that reveal that the source brightened in the X-rays by a factor of ∼10 one year after its discovery, while it faded in the UV/optical by a factor of ∼100. The XMM-Newton observations measure a soft X-ray blackbody component with {{kT}}{b…
iPTF Discovery of the Rapid “Turn-on” of a Luminous Quasar
Cenko, S. B.; Kulkarni, S. R.; Nugent, P. E. +13 more
We present a radio-quiet quasar at z = 0.237 discovered “turning on” by the intermediate Palomar Transient Factory (iPTF). The transient, iPTF 16bco, was detected by iPTF in the nucleus of a galaxy with an archival Sloan Digital Sky Survey spectrum with weak narrow-line emission characteristic of a low-ionization nuclear emission-line region (LINE…
Evidence for a Hard Ionizing Spectrum from a z = 6.11 Stellar Population
Kollmeier, Juna A.; Stark, Daniel P.; Newman, Andrew B. +4 more
We present the Magellan/FIRE detection of highly ionized C IV λ1550 and O III]λ1666 in a deep infrared spectrum of the z = 6.11 gravitationally lensed low-mass galaxy RXC J2248.7-4431-ID3, which has previously known Lyα. No corresponding emission is detected at the expected location of He II λ1640. The upper limit on He II, paired with detection o…
The Complete Calibration of the Color-Redshift Relation (C3R2) Survey: Survey Overview and Data Release 1
Castander, Francisco J.; Cohen, Judith G.; Paltani, Stéphane +4 more
A key goal of the Stage IV dark energy experiments Euclid, LSST, and WFIRST is to measure the growth of structure with cosmic time from weak lensing analysis over large regions of the sky. Weak lensing cosmology will be challenging: in addition to highly accurate galaxy shape measurements, statistically robust and accurate photometric redshift (ph…
Space Telescope and Optical Reverberation Mapping Project. V. Optical Spectroscopic Campaign and Emission-line Analysis for NGC 5548
Im, M.; Fox, O. D.; Malkan, M. A. +153 more
We present the results of an optical spectroscopic monitoring program targeting NGC 5548 as part of a larger multiwavelength reverberation mapping campaign. The campaign spanned 6 months and achieved an almost daily cadence with observations from five ground-based telescopes. The Hβ and He II λ4686 broad emission-line light curves lag that of the …
The Chemical Composition of an Extrasolar Kuiper-Belt-Object
Zuckerman, B.; Xu, S.; Dufour, P. +3 more
The Kuiper Belt of our solar system is a source of short-period comets that may have delivered water and other volatiles to Earth and the other terrestrial planets. However, the distribution of water and other volatiles in extrasolar planetary systems is largely unknown. We report the discovery of an accretion of a Kuiper-Belt-Object analog onto t…