Search Publications
Disentangling AGN and Star Formation in Soft X-Rays
Ptak, A.; Heckman, T. M.; LaMassa, Stephanie M.
We have explored the interplay of star formation and active galactic nucleus (AGN) activity in soft X-rays (0.5-2 keV) in two samples of Seyfert 2 galaxies (Sy2s). Using a combination of low-resolution CCD spectra from Chandra and XMM-Newton, we modeled the soft emission of 34 Sy2s using power-law and thermal models. For the 11 sources with high s…
Discrete Mass Ejections from the Be/X-Ray Binary A0535+26/HD 245770
Li, Hui; Yan, Jingzhi; Liu, Qingzhong
We present long-term optical spectroscopic observations on the Be/X-ray binary A0535+26 from 1992 to 2010. Combined with the public V-band photometric data, we find that each giant X-ray outburst occurred in a fading phase of the optical brightness. The anti-correlation between the optical brightness and the Hα intensity during our 2009 observatio…
SphinX Measurements of the 2009 Solar Minimum X-Ray Emission
Kuzin, S.; Phillips, K. J. H.; Reale, F. +9 more
The SphinX X-ray spectrophotometer on the CORONAS-PHOTON spacecraft measured soft X-ray emission in the 1-15 keV energy range during the deep solar minimum of 2009 with a sensitivity much greater than GOES. Several intervals are identified when the X-ray flux was exceptionally low, and the flux and solar X-ray luminosity are estimated. Spectral fi…
Impact of Systematics on SZ-Optical Scaling Relations
Miller, C. J.; Shaw, L.; Nord, B. +2 more
One of the central goals of multi-wavelength galaxy cluster cosmology is to unite all cluster observables to form a consistent understanding of cluster mass. Here, we study the impact of systematic effects from optical cluster catalogs on stacked Sunyaev-Zel'dovich (SZ) signals. We show that the optically predicted Y-decrement can vary by as much …
First Detection of Hydrogen Chloride Toward Protostellar Shocks
Codella, C.; Ceccarelli, C.; Caux, E. +8 more
We present the first detection of hydrogen chloride in a protostellar shock by observing the fundamental transition at 626 GHz with the HIFI spectrometer. We detected two of the three hyperfine lines from which we derived a line opacity <=1. Using a non-local thermodynamic equilibrium large velocity gradient code, we constrained the HCl column …
A Three-dimensional View of the Remnant of Nova Persei 1901 (GK Per)
Corradi, R. L. M.; Santander-García, M.; Rodríguez-Gil, P. +4 more
We present a kinematical study of the optical ejecta of GK Per. It is based on proper-motion measurements of 282 knots from ~20 images spanning 25 years. Doppler shifts are also computed for 217 knots. The combination of proper motions and radial velocities allows a unique three-dimensional view of the ejecta to be obtained. The main results are a…
DRAFTS: A Deep, Rapid Archival Flare Transient Search in the Galactic Bulge
Hawley, Suzanne L.; Osten, Rachel A.; Sahu, Kailash +1 more
We utilize the Sagittarius Window Eclipsing Extrasolar Planet Search Hubble Space Telescope/Advanced Camera for Surveys data set for a Deep Rapid Archival Flare Transient Search to constrain the flare rate toward the older stellar population in the Galactic bulge. During seven days of monitoring 229,293 stars brighter than V = 29.5, we find eviden…
Double Horizontal Branches in NGC 6440 and NGC 6569 Unveiled by the VVV Survey
Minniti, Dante; Geisler, Doug; Moni Bidin, Christian +5 more
We report the discovery of a peculiar horizontal branch (HB) in NGC 6440 and NGC 6569, two massive and metal-rich Galactic globular clusters (GGCs) located in the Galactic bulge, within 4 kpc from the Galactic center. In both clusters, two distinct clumps are detected at the level of the cluster HB, separated by only ~0.1 mag in the K s…
Thermal to Nonthermal Energy Partition at the Early Rise Phase of Solar Flares
Fleishman, Gregory D.; Altyntsev, Alexander A.; Lesovoi, Sergey V. +1 more
In some flares, the thermal component appears much earlier than the nonthermal component in the X-ray range. Using sensitive microwave observations, we revisit this finding made by Battaglia et al. based on a thorough analysis of RHESSI data. We have found that nonthermal microwave emission produced by accelerated electrons with energy of at least…
The Central Engine Structure of 3C120: Evidence for a Retrograde Black Hole or a Refilling Accretion Disk
Reynolds, Christopher S.; Cowperthwaite, Philip S.
The broad-line radio galaxy 3C120 is a powerful source of both X-ray and radio emission including superluminal jet outflows. We report on our reanalysis of 160 ks of Suzaku data taken in 2006, previously examined by Kataoka et al. Spectral fits to the X-ray Imaging Spectrometer and Hard X-ray Detector/positive intrinsic negative data over a range …