Search Publications
NuSTAR Unveils a Compton-thick Type 2 Quasar in Mrk 34
Harrison, F. A.; Stern, D.; Zhang, W. W. +27 more
We present Nuclear Spectroscopic Telescope Array (NuSTAR) 3-40 keV observations of the optically selected Type 2 quasar (QSO2) SDSS J1034+6001 or Mrk 34. The high-quality hard X-ray spectrum and archival XMM-Newton data can be fitted self-consistently with a reflection-dominated continuum and a strong Fe Kα fluorescence line with equivalent width …
New light on gamma-ray burst host galaxies with Herschel
Berta, S.; Le Floc'h, E.; Covino, S. +17 more
Until recently, dust emission has been detected in very few host galaxies of gamma-ray bursts (GRBHs). With Herschel, we have now observed 17 GRBHs up to redshift z ~ 3 and detected 7 of them at infrared (IR) wavelengths. This relatively high detection rate (41%) may be due to the composition of our sample which at a median redshift of 1.1 is domi…
Solar Cycle Variation in Solar Irradiance
Solanki, S. K.; Yeo, K. L.; Krivova, N. A.
The correlation between solar irradiance and the 11-year solar activity cycle is evident in the body of measurements made from space, which extend over the past four decades. Models relating variation in solar irradiance to photospheric magnetism have made significant progress in explaining most of the apparent trends in these observations. There …
The Angular Clustering of WISE-selected Active Galactic Nuclei: Different Halos for Obscured and Unobscured Active Galactic Nuclei
Stern, D.; Assef, R. J.; Yan, Lin +1 more
We calculate the angular correlation function for a sample of ~170,000 active galactic nuclei (AGNs) extracted from the Wide-field Infrared Survey Explorer (WISE) catalog, selected to have red mid-IR colors (W1 - W2 > 0.8) and 4.6 µm flux densities brighter than 0.14 mJy). The sample is expected to be >90% reliable at identifying AGNs …
Depleted cores, multicomponent fits, and structural parameter relations for luminous early-type galaxies
Graham, Alister W.; Dullo, Bililign T.
New surface brightness profiles from 26 early-type galaxies with suspected partially depleted cores have been extracted from the full radial extent of Hubble Space Telescope images. We have carefully quantified the radial stellar distributions of the elliptical galaxies using the core-Sérsic model whereas for the lenticular galaxies a core-Sérsic …
A Survey for Hα Pulsar Bow Shocks
Romani, Roger W.; Brownsberger, Sasha
We report on a survey for Hα bow shock emission around nearby γ-detected energetic pulsars. This survey adds three Balmer-dominated neutron star bow shocks to the six previously confirmed examples. In addition to the shock around Fermi pulsar PSR J1741-2054, we now report Hα structures around two additional γ-ray pulsars, PSR J2030+4415 and PSR J1…
A giant radio halo in the cool core cluster CL1821+643.
Sommer, M.; Fabian, A. C.; Cassano, R. +8 more
Giant radio haloes are Mpc-size sources found in some merging galaxy clusters. The synchrotron emitting electrons are thought to be (re)accelerated by plasma turbulence induced by the merging of two massive clusters. Cool core galaxy clusters have a low-temperature core, likely an indication that a major merger has not recently occurred. CL1821+64…
CO(1-0) survey of high-z radio galaxies: alignment of molecular halo gas with distant radio sources
Ivison, R. J.; Pentericci, L.; Greve, T. R. +19 more
We present a CO(1-0) survey for cold molecular gas in a representative sample of 13 high-z radio galaxies (HzRGs) at 1.4 < z < 2.8, using the Australia Telescope Compact Array. We detect CO(1-0) emission associated with five sources: MRC 0114-211, MRC 0152-209, MRC 0156-252, MRC 1138-262 and MRC 2048-272. The CO(1-0) luminosities are in the …
Tidally Modulated Eruptions on Enceladus: Cassini ISS Observations and Models
Nimmo, Francis; Porco, Carolyn; Mitchell, Colin
We use images acquired by the Cassini Imaging Science Subsystem (ISS) to investigate the temporal variation of the brightness and height of the south polar plume of Enceladus. The plume's brightness peaks around the moon's apoapse, but with no systematic variation in scale height with either plume brightness or Enceladus' orbital position. We comp…
Detection of White Dwarf Companions to Blue Stragglers in the Open Cluster NGC 188: Direct Evidence for Recent Mass Transfer
Sills, Alison; Knigge, Christian; Leigh, Nathan +3 more
Several possible formation pathways for blue straggler stars have been developed recently, but no one pathway has yet been observationally confirmed for a specific blue straggler. Here we report the first findings from a Hubble Space Telescope Advanced Camera for Surveys/Solar Blind Channel far-UV photometric program to search for white dwarf comp…