Search Publications
XMM-Newton Observations of the Dwarf Nova RU Peg in Quiescence: Probe of the Boundary Layer
Szkody, Paula; Sion, Edward M.; Balman, Şölen +4 more
We present an analysis of X-ray and UV data obtained with the XMM-Newton Observatory of the long-period dwarf nova RU Peg. RU Peg contains a massive white dwarf (WD), possibly the hottest WD in a dwarf nova (DN), it has a low inclination, thus optimally exposing its X-ray emitting boundary layer (BL), and has an excellent trigonometric parallax di…
The History of Star Formation in Galaxy Disks in the Local Volume as Measured by the Advanced Camera for Surveys Nearby Galaxy Survey Treasury
de Jong, Roelof S.; Williams, Benjamin F.; Gilbert, Karoline M. +9 more
We present a measurement of the age distribution of stars residing in spiral disks and dwarf galaxies. We derive a complete star formation history of the ~140 Mpc3 covered by the volume-limited sample of galaxies in the Advanced Camera for Surveys (ACS) Nearby Galaxy Survey Treasury (ANGST). The total star formation rate density history…
HST/COS Spectra of DF Tau and V4046 Sgr: First Detection of Molecular Hydrogen Absorption Against the Lyα Emission Line
France, Kevin; Yang, Hao; Linsky, Jeffrey L.
We report the first detection of molecular hydrogen (H2) absorption in the Lyα emission line profiles of two classical T Tauri stars (CTTSs), DF Tau and V4046 Sgr, observed by the Hubble Space Telescope/Cosmic Origins Spectrograph. This absorption is the energy source for many of the Lyman-band H2 fluorescent lines commonly s…
Star Formation Rates and Stellar Masses of Hα Selected Star-forming Galaxies at z = 0.84: A Quantification of the Downsizing
Barro, Guillermo; Pérez-González, Pablo G.; Koo, David C. +4 more
In this work we analyze the physical properties of a sample of 153 star-forming galaxies at z ~ 0.84, selected by their Hα flux with a narrowband filter. B-band luminosities of the objects are higher than those of local star-forming galaxies. Most of the galaxies are located in the blue cloud, though some objects are detected in the green valley a…
Three-dimensional Photoionization Structure and Distances of Planetary Nebulae. IV. NGC 40
Monteiro, Hektor; Falceta-Gonçalves, Diego
Continuing our series of papers on the three-dimensional (3D) structure and accurate distances of planetary nebulae (PNe), we present here the results obtained for PN NGC 40. Using data from different sources and wavelengths, we construct 3D photoionization models and derive the physical quantities of the ionizing source and nebular gas. The proce…
Warm and Fuzzy: Temperature and Density Analysis of an Fe XV EUV Imaging Spectrometer Loop
Schmelz, J. T.; Pathak, S.; Saar, S. H. +3 more
The Hinode EUV Imaging Spectrometer (EIS) and X-Ray Telescope (XRT) were designed in part to work together. They have the same spatial resolution and cover different but overlapping coronal temperature ranges. These properties make a combined data set ideal for multithermal analysis, where EIS provides the best information on the cooler corona (lo…
Identification of a Population of X-ray-emitting Massive Stars in the Galactic Plane
Drake, Jeremy J.; Chakrabarty, Deepto; Lee, Julia C. +15 more
We present X-ray, infrared, optical, and radio observations of four previously unidentified Galactic plane X-ray sources: AX J163252-4746, AX J184738-0156, AX J144701-5919, and AX J144547-5931. Detection of each source with the Chandra X-ray Observatory has provided sub-arcsecond localizations, which we use to identify bright infrared counterparts…
Suzaku Observations of Three FeLoBAL Quasi-stellar Objects: SDSS J0943+5417, J1352+4239, and J1723+5553
Dai, Xinyu; Leighly, Karen M.; Sivakoff, Gregory R. +2 more
We present Suzaku observations of three iron low-ionization broad absorption line quasars (FeLoBALs). We detect J1723+5553 (3σ) in the observed 2-10 keV band, and constrain its intrinsic N H column density to N H > 6 × 1023 cm-2 by modeling its X-ray hardness ratio. We study the broadband spectral ind…
Anatomy of a Solar Flare: Measurements of the 2006 December 14 X-class Flare with GONG, Hinode, and RHESSI
Zharkova, V. V.; Matthews, S. A.; Zharkov, S.
Some of the most challenging observations to explain in the context of existing flare models are those related to the lower atmosphere and below the solar surface. Such observations, including changes in the photospheric magnetic field and seismic emission, indicate the poorly understood connections between energy release in the corona and its imp…
Extended Hard X-Ray Emission from the Vela Pulsar Wind Nebula
Götz, D.; Ponti, G.; Bouchet, L. +8 more
The nebula powered by the Vela pulsar is one of the best examples of an evolved pulsar wind nebula, allowing access to the particle injection history and the interaction with the supernova ejecta. We report on the INTEGRAL discovery of extended emission above 18 keV from the Vela nebula. The northern side has no known counterparts and it appears l…