Search Publications
Observations of an Emerging Flux Region Surge: Implications for Coronal Mass Ejections Triggered by Emerging Flux
Liu, Y.; Su, J. T.; Shibata, K. +2 more
It is well known that coronal mass ejections (CMEs) are often associated with flares and filament eruptions. Previous studies of CMEs, however, have not established any association between CMEs and surges. In this paper, we present a detailed analysis of a large emerging flux region (EFR) surge and a jetlike CME, both observed on 1998 April 16. Ou…
Bimodal Galaxies and Bimodality in Globular Cluster Systems
Forbes, Duncan A.
Various galaxy properties are not continuous over a large range in mass but rather reveal a remarkable transition or ``bimodality'' at a stellar mass of 3×1010 Msolar. These properties include colors, stellar populations, X-ray emission, and mass-to-light ratios. This behavior has been interpreted as the transition from hot t…
Pulse-Phase Spectroscopy of SMC X-1 with Chandra and XMM-Newton: Reprocessing by a Precessing Disk?
Hickox, R. C.; Vrtilek, S. D.
We present pulse-phase X-ray spectroscopy of the high-mass X-ray pulsar SMC X-1 from five different epochs, using Chandra X-Ray Observatory ACIS-S and XMM-Newton EPIC pn data. The X-ray spectrum consistently shows two distinct components, a hard power law and a soft blackbody with kTBB~0.18 keV. For all five epochs the hard component sh…
Discovery of a Light Echo from SN 2003gd
Sugerman, Ben E. K.
Archival HST/ACS data reveal details of a light echo around SN 2003gd in the galaxy M74, only the fifth supernova around which resolved echoes have been reported. An echo is detected 0.3" from the supernova between position angles of 250° and 360°, with a fainter signal present at a few other position angles. This material lies ~180 pc in front of…
The Ages of Elliptical Galaxies from Mid-Infrared Emission
Brighenti, Fabrizio; Mathews, William G.; Temi, Pasquale
The mid-infrared (10-20 µm) luminosity of elliptical galaxies is dominated by the integrated emission from circumstellar dust in red giant stars. As a single stellar population evolves, the rate of dusty mass loss from red giant stars decreases with time, so the mid-infrared luminosity should also decline with stellar age. To seek such a cor…
The X3 Flare of 2002 July 15
Li, Jing; LaBonte, B. J.; Mickey, D. L.
An X3-class flare occurred on 2002 July 15 with white-light emission and a complex filament eruption. Observations were made in the optical continuum, Hα, UV continuum, microwave, and soft X-rays, as well as with high-cadence longitudinal magnetograms. Within the preflare phase, intense heating is observed accompanying upward motion of the filamen…
Evidence of Correlated Titanium and Deuterium Depletion in the Galactic Interstellar Medium
Tripp, Todd M.; Howk, J. Christopher; Prochaska, Jason X.
Current measurements indicate that the deuterium abundance in diffuse interstellar gas varies spatially by a factor of ~4 among sight lines extending beyond the Local Bubble. One plausible explanation for the scatter is the variable depletion of D onto dust grains. To test this scenario, we have obtained high signal-to-noise, high- resolution prof…
The Early Multicolor Afterglow of GRB 050502a: Possible Evidence for a Uniform Medium with Density Clumps
Pian, E.; Masetti, N.; Steele, I. A. +10 more
The 2 m robotic Liverpool Telescope reacted promptly to the gamma-ray burst GRB 050502a, discovered by INTEGRAL, and started observing 3 minutes after the onset of the burst. The automatic identification of a bright afterglow with r'~15.8 mag triggered, for the first time, an observation sequence in the BVr'i' filters during the first hour after a…
Unraveling the Puzzle of the Eclipsing Polar SDSS J015543.40+002807.2 with XMM and Optical Photometry/Spectropolarimetry
Szkody, Paula; Solheim, Jan-Erik; Schmidt, Gary D. +6 more
The cataclysmic variable SDSS J015543.40+002807.2 is confirmed to be a magnetic system of the AM Herculis type. With an orbital period of 87.13 minutes, it is also the shortest period eclipsing Polar known. Monitoring with XMM-Newton finds a high-state light curve dominated by a single X-ray-emitting accretion pole located slightly prograde of the…
FUSE Observations of Interstellar and Intergalactic Absorption toward the X-Ray-bright BL Lacertae Object Markarian 421
Sembach, Kenneth R.; Savage, Blair D.; Fox, Andrew J. +1 more
High-quality Far Ultraviolet Spectroscopic Explorer (FUSE) observations at 20 km s-1 resolution of interstellar and intergalactic absorption from 910 to 1187 Å are presented for the X-ray-bright BL Lac object Mrk 421. These observations are supplemented with FUSE data for the distant halo stars BD +38°2182 and HD 93521 near the Mrk 421 …