Search Publications
Direct Imaging of Fine Structure in the Chromosphere of a Sunspot Umbra
Lites, B. W.; McIntosh, S. W.; de Wijn, A. G. +2 more
High-resolution imaging observations from the Hinode spacecraft in the Ca II H line are employed to study the dynamics of the chromosphere above a sunspot. We find that umbral flashes and other brightenings produced by the oscillation are extremely rich in fine structure, even beyond the resolving limit of our observations (0farcs22). The umbra is…
Chandra Observations of the Hybrid Morphology Radio Sources 3C 433 and 4C 65.15: FR IIs with Asymmetric Environments
Brandt, W. N.; Miller, B. P.
We present Chandra observations of the hybrid morphology radio sources 3C 433 and 4C 65.15, two members of the rare class of objects possessing an FR I jet on one side of the core and an FR II lobe on the other. The X-ray spectrum of 3C 433 shows intrinsic absorption (with a column density of N H sime 8 × 1022 cm-2…
The Circumstellar Medium of Cassiopeia a Inferred from the Outer Ejecta Knot Properties
Hwang, Una; Laming, J. Martin
We investigate the effect of the circumstellar medium density profile on the X-ray emission from outer ejecta knots in the Cassiopeia A supernova remnant using the 1 Ms Chandra observation. The spectra of a number of radial series of ejecta knots at various positions around the remnant are analyzed using techniques similar to those devised in prev…
The Suzaku View of the Swift/BAT Active Galactic Nuclei. II. Time Variability and Spectra of Five "Hidden" Active Galactic Nuclei
Ueda, Yoshihiro; Terashima, Yuichi; Mushotzky, Richard F. +1 more
The fraction of Compton-thick sources is one of the main uncertainties left in understanding the active galactic nucleus (AGN) population. The Swift Burst Alert Telescope (BAT) all-sky survey for the first time gives us an unbiased sample of AGNs for all but the most heavily absorbed sources N H > 1025 cm-2). St…
Direct Detection of a Flared Disk Around a Young Massive Star HD200775 and its 10 to 1000 AU Scale Properties
Onaka, T.; Sakon, I.; Kataza, Hirokazu +9 more
We made mid-infrared (MIR) observations of the 10 M sun Herbig Be star HD200775 with the Cooled Mid-Infrared Camera and Spectrometer on the 8.2 m Subaru Telescope. We discovered diffuse emission of an elliptical shape extended in the north-south direction in an ~1000 AU radius around unresolved excess emission. The diffuse emission is p…
Behavior of the Spines in a Quiescent Prominence Observed by Hinode/SOT
Goode, P. R.; Cao, W.; Ning, Z.
We report the behaviors of the spines in a quiescent prominence from the observations on 2008 January 15 made with Hinode/SOT in Hα +0.076 Å, Hα-0.34 Å, and Ca II H line filters. Two spines (1 and 2) are visible in this event. In the spacetime plots of the Hα and Ca II intensities, the two spines seem to gradually move closer together, and finally…
A Near-Infrared Excess in the Continuum of High-redshift Galaxies: A Tracer of Star Formation and Circumstellar Disks?
Glazebrook, Karl; McCarthy, Patrick J.; Yan, Haojing +13 more
A broad continuum excess in the near-infrared, peaking in the rest frame at 2-5 µm, is detected in a spectroscopic sample of 88 galaxies at 0.5 < z < 2.0 taken from the Gemini Deep Deep Survey. Line emission from polycyclic aromatic hydrocarbons (PAHs) at 3.3 µm alone cannot explain the excess, which can be fit by a spectral comp…
X-ray Observation of Very High Energy Gamma-Ray Source, HESS J1745-303, with Suzaku
Matsumoto, Hironori; Bamba, Aya; Pühlhofer, Gerd +4 more
Suzaku observations of a TeV unidentified source, HESS J1745-303, are presented. A possible excess of neutral iron line emission is discovered, and is likely associated with the main part of HESS J1745-303, named "region A." It may be an X-ray reflection nebula where the X-rays from previous Galactic center (GC) activity are reflected by a molecul…
Mass Segregation in NGC 2298: Limits on the Presence of an Intermediate Mass Black Hole
Stiavelli, Massimo; Hamilton, Douglas P.; van der Marel, Roeland P. +5 more
Theoretical investigations have suggested the presence of intermediate mass black holes (IMBHs, with masses in the 100-10000 M sun range) in the cores of some globular clusters (GCs). In this paper, we present the first application of a new technique to determine the presence or absence of a central IMBH in globular clusters that have r…
Elemental Abundances in the X-Ray Gas of Early-Type Galaxies with XMM-Newton and Chandra Observations
Bregman, Joel N.; Irwin, Jimmy A.; Ji, Jun +2 more
The source of hot gas in elliptical galaxies is thought to be due to stellar mass loss, with contributions from supernova (SN) events and possibly from infall from a surrounding environment. This picture predicts supersolar values for the metallicity of the gas toward the inner part of the galaxy, which can be tested by measuring the gas phase abu…