Search Publications
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 …
Absorption-Line Study of Halo Gas in NGC 3067 toward the Background Quasar 3C 232
Stocke, John T.; Keeney, Brian A.; Tumlinson, Jason +2 more
We present new H I 21 cm absorption data and ultraviolet spectroscopy from Hubble Space Telescope/Space Telescope Imaging Spectrograph of the QSO/galaxy pair 3C 232/NGC 3067. The QSO sight line lies near the minor axis and 1.8 arcmin (11 h-170 kpc) above the plane of NGC 3067, a nearby luminous (cz=1465+/-5 km s-1,…
Far-Ultraviolet Observations of the Globular Cluster NGC 2808 Revisited: Blue Stragglers, White Dwarfs, and Cataclysmic Variables
Knigge, C.; Long, K. S.; Zurek, D. R. +2 more
We present a reanalysis of far-ultraviolet (FUV) observations of the globular cluster NGC 2808 obtained with the Hubble Space Telescope. These data were first analyzed by Brown and coworkers, with an emphasis on the bright, blue horizontal-branch (HB) stars in this cluster. Here, our focus is on the population of fainter FUV sources, which include…
The Heliospheric He II 30.4 nm Solar Flux During Cycle 23
Auchère, F.; von Steiger, R.; Witte, M. +3 more
Because of the orbit characteristics of the vast majority of spacecraft, the solar flux has predominantly been measured at Earth or at least in the plane of the ecliptic. Therefore, the existing data do not directly demonstrate the fact that the latitudinal distribution of the extreme-ultraviolet (EUV) solar flux is largely anisotropic. Indeed, in…
Magnetic Helicity Injection and Sigmoidal Coronal Loops
Kusano, K.; Sakurai, T.; Yokoyama, T. +2 more
We studied the relationship between magnetic helicity injection and the formation of sigmoidal loops. We analyzed seven active regions: three regions showed coronal loops similar to the potential field, and four regions showed the sigmoidal loops. The magnetic helicity injection rate was evaluated using the method proposed by Kusano et al. In orde…
X-Ray Spectral Variability during an Outburst in V1118 Ori
Audard, M.; Güdel, M.; Briggs, K. R. +5 more
We present results from a multiwavelength campaign to monitor the 2005 outburst of the low-mass young star V1118 Ori. Although our campaign covers the X-ray, optical, infrared, and radio regimes, we focus in this Letter on the properties of the X-ray emission in V1118 Ori during the first few months after the optical outburst. Chandra and XMM-Newt…
3-200 keV Spectral States and Variability of the INTEGRAL Black Hole Binary IGR J17464-3213
Capitanio, F.; Bird, A. J.; Ubertini, P. +12 more
On March 2003, IBIS, the gamma-ray imager on board the INTEGRAL satellite, detected an outburst from a new source, IGR J17464-3213, that turned out to be a HEAO 1 transient, H1743-322. In this paper we report on the high-energy behavior of this black hole candidate (BHC) studied with the three main instruments on board INTEGRAL. The data, collecte…