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Suzaku Observes Weak Flares from IGR J17391-3021 Representing a Common Low-activity State in this Supergiant Fast X-ray Transient
Chaty, S.; Tomsick, J. A.; Rodriguez, J. +4 more
We present an analysis of a 37 ks observation of the supergiant fast X-ray transient IGR J17391-3021 (= XTE J1739-302) gathered with Suzaku. The source evolved from quiescence to a low-activity level culminating in three weak flares lasting ~3 ks each in which the peak luminosity is only a factor of five times that of the pre-flare luminosity. The…
Comparing Spatial Distributions of Solar Prominence Mass Derived from Coronal Absorption
Alexander, David; Kilper, Gary; Gilbert, Holly +1 more
In a previous study, Gilbert et al. derived the column density and total mass of solar prominences using a new technique, which measures how much coronal radiation in the Fe XII (195 Å) spectral band is absorbed by prominence material, while considering the effects of both foreground and background radiation. In the present work, we apply this met…
Interstellar Silicate Dust in Five Quasar Absorption Systems
York, Donald G.; Kulkarni, Varsha P.; Welty, Daniel E. +3 more
We report on a study of interstellar silicate dust in five quasar absorption systems at 0.44 < z abs < 1.31 toward quasars Q0235+164, 3C196, Q0852+3435, Q0937+5628, and Q1203+0634, using data from the Infrared Spectrograph on board the Spitzer Space Telescope. In the absorbers toward Q0235+164, 3C196, Q0852+3435, and Q0937+5628, t…
Fe K Line Complex in the Nuclear Region of NGC 253
Yamasaki, Noriko Y.; Mitsuishi, Ikuyuki; Takei, Yoh
A bright, nearby edge-on starburst galaxy, NGC 253, was studied using the Suzaku, XMM, and Chandra X-ray observatories. With Suzaku and XMM we detected complex line structure of Fe K, which is resolved into three lines (Fe I at 6.4 keV, Fe XXV at 6.7 keV, and Fe XXVI at 7.0 keV) around the center of NGC 253. Especially, the Fe I and Fe XXVI lines …
Gas and Dust Toward DG Tau B and VV CrA
Najita, Joan R.; Doppmann, Greg W.; Seifahrt, Andreas +3 more
We present findings for DG Tau B and VV CrA, two of the objects observed in our Spitzer Infrared Spectrograph (IRS) project to search for molecular absorption in edge-on disks, along with near-IR spectroscopy of the CO fundamental transitions and mid-IR imaging. While the only gas absorption seen in the Spitzer IRS spectrum toward DG Tau B is CO
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…