Search Publications
PS1-12sk is a Peculiar Supernova from a He-rich Progenitor System in a Brightest Cluster Galaxy Environment
Price, P. A.; Berger, E.; Kirshner, R. P. +29 more
We report on our discovery and observations of the Pan-STARRS1 supernova (SN) PS1-12sk, a transient with properties that indicate atypical star formation in its host galaxy cluster or pose a challenge to popular progenitor system models for this class of explosion. The optical spectra of PS1-12sk classify it as a Type Ibn SN (SN Ibn cf. SN 2006jc)…
Discovery of the Recombining Plasma in the South of the Galactic Center: A Relic of the Past Galactic Center Activity?
Koyama, K.; Tanaka, T.; Murakami, H. +5 more
We report Suzaku results for soft X-ray emission to the south of the Galactic center (GC). The emission (hereafter "GC South") has an angular size of ~42' × 16' centered at (l, b) ~ (0.°0, - 1.°4) and is located in the largely extended Galactic ridge X-ray emission (GRXE). The X-ray spectrum of GC South exhibits emission lines from highly ionized …
The HETDEX Pilot Survey. IV. The Evolution of [O II] Emitting Galaxies from z ~ 0.5 to z ~ 0
Finkelstein, Steven L.; Schneider, Donald P.; Blanc, Guillermo A. +10 more
We present an analysis of the luminosities and equivalent widths of the 284 z < 0.56 [O II]-emitting galaxies found in the 169 arcmin2 pilot survey for the Hobby-Eberly Telescope Dark Energy Experiment (HETDEX). By combining emission-line fluxes obtained from the Mitchell spectrograph on the McDonald 2.7 m telescope with deep broadba…
Detection of Substructure in the Gravitationally Lensed Quasar MG0414+0534 Using Mid-infrared and Radio VLBI Observations
Kochanek, Christopher S.; Agol, Eric; MacLeod, Chelsea L. +1 more
We present 11.2 µm observations of the gravitationally lensed, radio-loud zs = 2.64 quasar MG0414+0534, obtained using the Michelle camera on Gemini North. We find a flux ratio anomaly of A2/A1 = 0.93 ± 0.02 for the quasar images A1 and A2. When combined with the 11.7 µm measurements from Minezaki et al., the A2/A1 flux rati…
The Atacama Cosmology Telescope: Relation between Galaxy Cluster Optical Richness and Sunyaev-Zel'dovich Effect
Hilton, Matt; Hasselfield, Matthew; Sifón, Cristóbal +33 more
We present the measured Sunyaev-Zel'dovich (SZ) flux from 474 optically selected MaxBCG clusters that fall within the Atacama Cosmology Telescope (ACT) Equatorial survey region. The ACT Equatorial region used in this analysis covers 510 deg2 and overlaps Stripe 82 of the Sloan Digital Sky Survey. We also present the measured SZ flux sta…
Hα Star Formation Rates of z > 1 Galaxy Clusters in the IRAC Shallow Cluster Survey
Moustakas, John; Dey, Arjun; Gonzalez, Anthony H. +7 more
We present Hubble Space Telescope near-IR spectroscopy for 18 galaxy clusters at 1.0 <z < 1.5 in the IRAC Shallow Cluster Survey. We use Wide Field Camera 3 grism data to spectroscopically identify Hα emitters in both the cores of galaxy clusters as well as in field galaxies. We find a large cluster-to-cluster scatter in the star formation r…
A Rest-frame Optical View on z ~ 4 Galaxies. I. Color and Age Distributions from Deep IRAC Photometry of the IUDF10 and GOODS Surveys
Trenti, M.; Oesch, P. A.; Bouwens, R. J. +7 more
We present a study of rest-frame UV-to-optical color distributions for z ~ 4 galaxies based on the combination of deep HST/ACS+WFC3/IR data with Spitzer/IRAC imaging. In particular, we use new, ultra-deep data from the IRAC Ultradeep Field program (IUDF10), together with previous, public IRAC data over the GOODS fields. Our sample contains a total…
C IV Line-width Anomalies: The Perils of Low Signal-to-noise Spectra
Kochanek, C. S.; Vestergaard, M.; Peterson, B. M. +3 more
Comparison of six high-redshift quasar spectra obtained with the Large Binocular Telescope with previous observations from the Sloan Digital Sky Survey shows that failure to correctly identify absorption and other problems with accurate characterization of the C IV λ1549 emission line profile in low signal-to-noise (S/N) data can severely limit th…
Faint Submillimeter Galaxy Counts at 450 µm
Chen, Chian-Chou; Lee, Nicholas; Williams, Jonathan P. +5 more
We present the results of SCUBA-2 observations at 450 µm and 850 µm of the field lensed by the massive cluster A370. With a total survey area >100 arcmin2 and 1σ sensitivities of 3.92 and 0.82 mJy beam-1 at 450 and 850 µm, respectively, we find a secure sample of 20 sources at 450 µm and 26 sources …
In Situ Measurements of the Size and Density of Titan Aerosol Analogs
Hörst, S. M.; Tolbert, M. A.
The organic haze produced from complex CH4/N2 chemistry in the atmosphere of Titan plays an important role in processes that occur in the atmosphere and on its surface. The haze particles act as condensation nuclei and are therefore involved in Titan's methane hydrological cycle. They also may behave like sediment on Titan's …