Search Publications
Pulse-phase-resolved Spectroscopy of Vela X-1 with Suzaku
Maitra, Chandreyee; Paul, Biswajit
We present a detailed pulse-phase-resolved spectral analysis of the persistent high-mass X-ray binary pulsar Vela X-1 observed with Suzaku during 2008 June. The pulse profiles exhibit both intensity and energy dependence with multiple peaks at low energies and double peaks at higher energies. The source shows some spectral evolution over the durat…
The Age and Stellar Parameters of the Procyon Binary System
Liebert, James; Williams, Kurtis A.; Fontaine, Gilles +2 more
The Procyon AB binary system (orbital period 40.838 yr, a newly refined determination) is near and bright enough that the component radii, effective temperatures, and luminosities are very well determined, although more than one possible solution to the masses has limited the claimed accuracy. Preliminary mass determinations for each component are…
X-Ray Groups of Galaxies in the AEGIS Deep and Wide Fields
Finoguenov, A.; Nandra, K.; Laird, E. +19 more
We present the results of a search for extended X-ray sources and their corresponding galaxy groups from 800 ks Chandra coverage of the All-wavelength Extended Groth Strip International Survey (AEGIS). This yields one of the largest X-ray-selected galaxy group catalogs from a blind survey to date. The red-sequence technique and spectroscopic redsh…
Stochastic Coupling of Solar Photosphere and Corona
Coyner, Aaron J.; Ofman, Leon; Davila, Joseph M. +1 more
The observed solar activity is believed to be driven by the dissipation of nonpotential magnetic energy injected into the corona by dynamic processes in the photosphere. The enormous range of scales involved in the interaction makes it difficult to track down the photospheric origin of each coronal dissipation event, especially in the presence of …
The Complex Physics of Dusty Star-forming Galaxies at High Redshifts as Revealed by Herschel and Spitzer
Berta, S.; Magnelli, B.; Lutz, D. +29 more
We combine far-infrared photometry from Herschel (PEP/HerMES) with deep mid-infrared spectroscopy from Spitzer to investigate the nature and the mass assembly history of a sample of 31 luminous and ultraluminous infrared galaxies ((U)LIRGs) at z ~ 1 and 2 selected in GOODS-S with 24 µm fluxes between 0.2 and 0.5 mJy. We model the data with a…
SWIFT J1910.2-0546: A Possible Black Hole Binary with a Retrograde Spin or Truncated Disk
Degenaar, N.; Miller, J. M.; Reis, R. C. +4 more
We present the first results from a long (51 ks) XMM-Newton observation of the Galactic X-ray binary SWIFT J1910.2-0546 in an intermediate state, obtained during its 2012 outburst. A clear, asymmetric iron emission line is observed and physically motivated models are used to fully describe the emission-line profile. Unlike other sources in their i…
A Detailed Comparison between the Observed and Synthesized Properties of a Simulated Type II Spicule
Martínez-Sykora, Juan; De Pontieu, Bart; Hansteen, Viggo +7 more
We have performed a three-dimensional radiative MHD simulation of the solar atmosphere. This simulation shows a jet-like feature that shows similarities to the type II spicules observed for the first time with Hinode's Solar Optical Telescope. Rapid blueshifted events (RBEs) on the solar disk are associated with these spicules. Observational resul…
Quantifying Mass Segregation and New Core Radii for 54 Milky Way Globular Clusters
Heyl, Jeremy; Richer, Harvey; Goldsbury, Ryan
We present core radii for 54 Milky Way globular clusters determined by fitting King-Michie models to cumulative projected star count distributions. We find that fitting star counts rather than surface brightness profiles produces results that differ significantly due to the presence of mass segregation. The sample in each cluster is further broken…
Unveiling the σ-discrepancy. II. Revisiting the Evolution of ULIRGs and the Origin of Quasars
Sanders, D. B.; Rothberg, Barry; Rodrigues, Myriam +1 more
We present the first central velocity dispersions (σcircle) measured from the 0.85 µm Calcium II Triplet (CaT) for eight advanced (i.e., single nuclei) local (z <= 0.15) Ultraluminous Infrared Galaxies (ULIRGs). First, these measurements are used to test the prediction that the "σ-Discrepancy," in which the CaT σcircle
A Non-LTE Analysis of the Hot Subdwarf O Star BD+28°4211. I. The UV Spectrum
Latour, M.; Chayer, P.; Fontaine, G. +1 more
We present a detailed analysis of the UV spectrum of the calibration star BD+28°4211 using high-quality spectra obtained with the Hubble Space Telescope and Far-Ultraviolet Spectroscopic Explorer satellites. To this aim, we compare quantitatively the observed data with model spectra obtained from state-of-the-art non-LTE metal line-blanketed model…