Search Publications
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…
A Spectroscopic Search for AGN Activity in the Reionization Era
Stark, Daniel P.; Ellis, Richard S.; Zitrin, Adi +4 more
The ubiquity of Lyman alpha (Lyα) emission in a sample of four bright [O III]-strong star-forming galaxies with redshifts above seven has led to the suggestion that such luminous sources represent a distinct population compared with their fainter, more numerous counterparts. The presence of Lyα emission within the reionization era could indicate t…
A Neutron Star Binary Merger Model for GW170817/GRB 170817A/SSS17a
Lee, W. H.; Rest, A.; Foley, R. J. +14 more
The merging neutron star gravitational-wave event GW170817 has been observed throughout the entire electromagnetic spectrum from radio waves to γ-rays. The resulting energetics, variability, and light curves are shown to be consistent with GW170817 originating from the merger of two neutron stars, in all likelihood followed by the prompt gravitati…
Bulge-forming Galaxies with an Extended Rotating Disk at z ~ 2
Übler, Hannah; Tamura, Yoichi; Kohno, Kotaro +24 more
We present 0.″2-resolution Atacama Large Millimeter/submillimeter Array observations at 870 µm for 25 Hα-seleced star-forming galaxies around the main sequence at z = 2.2-2.5. We detect significant 870 µm continuum emission in 16 (64%) of these galaxies. The high-resolution maps reveal that the dust emission is mostly radiated from a s…
A New, Large-scale Map of Interstellar Reddening Derived from H I Emission
Hensley, Brandon S.; Doré, Olivier; Lenz, Daniel
We present a new map of interstellar reddening, covering the 39% of the sky with low H I column densities (NHI< 4× 1020 cm-2 or E(B-V)≈ 45 mmag) at 16.1\prime resolution, based on all-sky observations of Galactic H I emission by the HI4PI Survey. In this low-column-density regime, we derive a characteristic valu…