Search Publications
The Man behind the Curtain: X-Rays Drive the UV through NIR Variability in the 2013 Active Galactic Nucleus Outburst in NGC 2617
Im, M.; Choi, C.; Yoon, Y. +44 more
After the All-Sky Automated Survey for SuperNovae discovered a significant brightening of the inner region of NGC 2617, we began a ~70 day photometric and spectroscopic monitoring campaign from the X-ray through near-infrared (NIR) wavelengths. We report that NGC 2617 went through a dramatic outburst, during which its X-ray flux increased by over …
3D-HST+CANDELS: The Evolution of the Galaxy Size-Mass Distribution since z = 3
Wuyts, S.; Ferguson, H. C.; Brammer, G. B. +27 more
Spectroscopic+photometric redshifts, stellar mass estimates, and rest-frame colors from the 3D-HST survey are combined with structural parameter measurements from CANDELS imaging to determine the galaxy size-mass distribution over the redshift range 0 < z < 3. Separating early- and late-type galaxies on the basis of star-formation activity, …
Constraining the Low-mass Slope of the Star Formation Sequence at 0.5 < z < 2.5
Henry, Alaina; van Dokkum, Pieter G.; Franx, Marijn +9 more
We constrain the slope of the star formation rate (SFR; log Ψ) to stellar mass (log M sstarf) relation down to log (M sstarf/M ⊙) = 8.4 (log (M sstarf/M ⊙) = 9.2) at z = 0.5 (z = 2.5) with a mass-complete sample of 39,106 star-forming galaxies selected from the 3D-HST photometric catalogs, usi…
Detection of an Unidentified Emission Line in the Stacked X-Ray Spectrum of Galaxy Clusters
Bulbul, Esra; Loewenstein, Michael; Markevitch, Maxim +3 more
We detect a weak unidentified emission line at E = (3.55-3.57) ± 0.03 keV in a stacked XMM-Newton spectrum of 73 galaxy clusters spanning a redshift range 0.01-0.35. When the full sample is divided into three subsamples (Perseus, Centaurus+Ophiuchus+Coma, and all others), the line is seen at >3σ statistical significance in all three independent…
Improved Reflection Models of Black Hole Accretion Disks: Treating the Angular Distribution of X-Rays
Reynolds, C. S.; García, J.; Dauser, T. +8 more
X-ray reflection models are used to constrain the properties of the accretion disk, such as the degree of ionization of the gas and the elemental abundances. In combination with general relativistic ray tracing codes, additional parameters like the spin of the black hole and the inclination to the system can be determined. However, current reflect…
The COS-Halos Survey: Physical Conditions and Baryonic Mass in the Low-redshift Circumgalactic Medium
Tripp, Todd M.; Prochaska, J. Xavier; Tejos, Nicolas +13 more
We analyze the physical conditions of the cool, photoionized (T ~104 K) circumgalactic medium (CGM) using the COS-Halos suite of gas column density measurements for 44 gaseous halos within 160 kpc of L ~ L* galaxies at z ~ 0.2. These data are well described by simple photoionization models, with the gas highly ionized (n H II
Toward the Standard Population Synthesis Model of the X-Ray Background: Evolution of X-Ray Luminosity and Absorption Functions of Active Galactic Nuclei Including Compton-thick Populations
Ueda, Yoshihiro; Akiyama, Masayuki; Miyaji, Takamitsu +2 more
We present the most up to date X-ray luminosity function (XLF) and absorption function of active galactic nuclei (AGNs) over the redshift range from 0 to 5, utilizing the largest, highly complete sample ever available obtained from surveys performed with Swift/BAT, MAXI, ASCA, XMM-Newton, Chandra, and ROSAT. The combined sample, including that of …
The Star Formation Histories of Local Group Dwarf Galaxies. I. Hubble Space Telescope/Wide Field Planetary Camera 2 Observations
Dolphin, Andrew E.; Skillman, Evan D.; Williams, Benjamin F. +4 more
We present uniformly measured star formation histories (SFHs) of 40 Local Group (LG) dwarf galaxies based on color-magnitude diagram (CMD) analysis from archival Hubble Space Telescope imaging. We demonstrate that accurate SFHs can be recovered from CMDs that do not reach the oldest main sequence turn-off (MSTO), but emphasize that the oldest MSTO…
UV-continuum Slopes of >4000 z ~ 4-8 Galaxies from the HUDF/XDF, HUDF09, ERS, CANDELS-South, and CANDELS-North Fields
Trenti, M.; Oesch, P. A.; Bouwens, R. J. +7 more
We measure the UV-continuum slope β for over 4000 high-redshift galaxies over a wide range of redshifts z ~ 4-8 and luminosities from the HST HUDF/XDF, HUDF09-1, HUDF09-2, ERS, CANDELS-N, and CANDELS-S data sets. Our new β results reach very faint levels at z ~ 4 (-15.5 mag: 0.006 Lz=3*), z ~ 5 (-16.5 mag: 0.014 Lz=3
Galaxy Stellar Mass Functions from ZFOURGE/CANDELS: An Excess of Low-mass Galaxies since z = 2 and the Rapid Buildup of Quiescent Galaxies
Papovich, Casey; Kelson, Daniel D.; Kacprzak, Glenn G. +16 more
Using observations from the FourStar Galaxy Evolution Survey (ZFOURGE), we obtain the deepest measurements to date of the galaxy stellar mass function (SMF) at 0.2 < z < 3. ZFOURGE provides well-constrained photometric redshifts made possible through deep medium-bandwidth imaging at 1-2 µm. We combine this with Hubble Space Telescope i…