Search Publications
Star formation rates in luminous quasars at 2 < z < 3
Clements, David L.; Chapman, Scott; Vieira, Joaquin +22 more
We investigate the relation between star formation rates (dot{{M}}_s) and AGN properties in optically selected type 1 quasars at 2 < z < 3 using data from Herschel and the SDSS. We find that dot{{M}}_s remains approximately constant with redshift, at 300 ± 100 M⊙ yr-1. Conversely, dot{{M}}_s increases with AGN luminosit…
Exploring the Overabundance of ULXs in Metal- and Dust-poor Local Lyman Break Analogs
Zezas, Andreas; Hornschemeier, Ann; Ptak, Andy +4 more
We have studied high-mass X-ray binary (HMXB) populations within two low-metallicity, starburst galaxies, Haro 11 and VV 114. These galaxies serve as analogs to high-redshift (z\gt 2) Lyman break galaxies and, within the larger sample of Lyman break analogs (LBAs), they are sufficiently nearby (<87 Mpc) to be spatially resolved by Chandra. Prev…
Surface Temperatures on Titan during Northern Winter and Spring
Flasar, F. M.; Coustenis, A.; Achterberg, R. K. +9 more
Meridional brightness temperatures were measured on the surface of Titan during the 2004-2014 portion of the Cassini mission by the Composite Infrared Spectrometer. Temperatures mapped from pole to pole during five two-year periods show a marked seasonal dependence. The surface temperature near the south pole over this time decreased by 2 K from 9…
Fe Line Diagnostics of Cataclysmic Variables and Galactic Ridge X-Ray Emission
Wang, Q. Daniel; Li, Xiang-Dong; Xu, Xiao-jie
The properties of the Galactic Ridge X-ray Emission (GRXE) observed in the 2-10 keV band place fundamental constraints on various types of X-ray sources in the Milky Way. Although the primarily discrete origin of the emission is now well established, the responsible populations of these sources remain uncertain, especially at relatively low fluxes…
Probing the Outskirts of the Early-Stage Galaxy Cluster Merger A1750
Sarazin, Craig L.; Bayliss, Matthew; Andrade-Santos, Felipe +12 more
We present results from recent Suzaku and Chandra X-ray and Multiple Mirrior Telescope optical observations of the strongly merging “double cluster” A1750 out to its virial radius, both along and perpendicular to a putative large-scale structure filament. Some previous studies of individual clusters have found evidence for ICM entropy profiles tha…
On the Composition of Young, Directly Imaged Giant Planets
Fortney, J. J.; Zahnle, K.; Moses, J. I. +6 more
The past decade has seen significant progress on the direct detection and characterization of young, self-luminous giant planets at wide orbital separations from their host stars. Some of these planets show evidence for disequilibrium processes like transport-induced quenching in their atmospheres; photochemistry may also be important, despite the…
Anatomy of the AGN in NGC 5548. VIII. XMM-Newton's EPIC detailed view of an unexpected variable multilayer absorber
Kaastra, J. S.; Harrison, F. A.; Kriss, G. A. +21 more
In 2013, we conducted a large multi-wavelength campaign on the archetypical Seyfert 1 galaxy NGC 5548. Unexpectedly, this usually unobscured source appeared strongly absorbed in the soft X-rays during the entire campaign, and signatures of new and strong outflows were present in the almost simultaneous UV HST/COS data. Here we carry out a comprehe…
Quantifying the (X/peanut)-shaped structure in edge-on disc galaxies: length, strength, and nested peanuts
Ciambur, Bogdan C.; Graham, Alister W.
X-shaped or peanut-shaped (X/P) bulges are observed in more than 40 per cent of (nearly) edge-on disc galaxies, though to date a robust method to quantify them is lacking. Using Fourier harmonics to describe the deviation of galaxy isophotes from ellipses, we demonstrate with a sample of 11 such galaxies (including NGC 128) that the sixth Fourier …
Beyond spheroids and discs: classifications of CANDELS galaxy structure at 1.4 < z < 2 via principal component analysis
Papovich, Casey; Barro, Guillermo; Grogin, Norman A. +15 more
Important but rare and subtle processes driving galaxy morphology and star formation may be missed by traditional spiral, elliptical, irregular or Sérsic bulge/disc classifications. To overcome this limitation, we use a principal component analysis (PCA) of non-parametric morphological indicators (concentration, asymmetry, Gini coefficient, M…
The Contribution of Host Galaxies to the Infrared Energy Output of z ≳ 5.0 Quasars
Lyu, Jianwei; Alberts, Stacey; Rieke, G. H.
The infrared spectral energy distributions of z ≳ 5 quasars can be reproduced by combining a low-metallicity galaxy template with a standard active galactic nucleus (AGN) template. The host galaxy is represented by Haro 11, a compact, moderately low metallicity, starbursting galaxy that shares typical features of high-z galaxies. For the vast majo…