Search Publications
Implications of Solar Wind Composition for Cometary X-Rays
Schwadron, N. A.; Cravens, T. E.
Solar wind composition provides a strong source of variability for cometary X-rays. Using recently constrained composition observations from the Solar Wind Ion Composition Spectrometer on the Ulysses spacecraft (SWICS/Ulysses) and information on ion-neutral charge-transfer collisions, we model cometary X-ray emission and its variability. Fast and …
A Jet Model for the Afterglow Emission from GRB 000301C
Menten, K. M.; Galama, T. J.; Berger, E. +11 more
We present broadband radio observations of the afterglow of GRB 000301C, spanning from 1.4 to 350 GHz for the period of 3-130 days after the burst. These radio data, in addition to measurements in the optical bands, suggest that the afterglow arises from a collimated outflow, i.e., a jet. To test this hypothesis in a self-consistent manner, we emp…
The Very Red Afterglow of GRB 000418: Further Evidence for Dust Extinction in a Gamma-Ray Burst Host Galaxy
Pian, E.; Palazzi, E.; Greiner, J. +36 more
We report near-infrared and optical follow-up observations of the afterglow of the GRB 000418 starting 2.5 days after the occurrence of the burst and extending over nearly 7 weeks. GRB 000418 represents the second case for which the afterglow was initially identified by observations in the near-infrared. During the first 10 days its R-band aftergl…
Evidence of a North-South Asymmetry in the Heliosphere Associated with a Southward Displacement of the Heliospheric Current Sheet
Smith, E. J.; Szabo, A.; Lepping, R. P. +2 more
Evidence of a north-south asymmetry in the global heliosphere, first inferred from Ulysses cosmic-ray observations, is investigated using simultaneous Ulysses and Wind magnetic field observations. Such an asymmetry, presumably associated with a southward displacement of the heliospheric current sheet (HCS), is expected to produce significantly dif…
Prompt Optical Observations of Gamma-Ray Bursts
Hurley, Kevin; McKay, Tim; Kehoe, Robert +18 more
The Robotic Optical Transient Search Experiment (ROTSE) seeks to measure simultaneous and early afterglow optical emission from gamma-ray bursts (GRBs). A search for optical counterparts to six GRBs with localization errors of 1 deg2 or better produced no detections. The earliest limiting sensitivity is mROTSE>13.1 at 10.8…
Observations of a Possible New Soft Gamma Repeater, SGR 1801-23
Cline, T.; Hurley, K.; Kouveliotou, C. +4 more
We report on two 1997 June observations of a soft bursting source whose time histories and energy spectra are consistent with those of the soft gamma repeaters. The source can be localized only to an ~3.8d long error box in the direction of the Galactic center, whose area is ~80 arcmin2. The location of the source, while not consistent …
Interplanetary Network Localization of GRB 991208 and the Discovery of its Afterglow
Cline, T.; Hurley, K.; Golenetskii, S. +9 more
The extremely energetic (~10-4 ergs cm-2) gamma-ray burst (GRB) of 1999 December 8 was triangulated to an ~14 arcmin2 error box ~1.8 days after its arrival at Earth with the third interplanetary network (IPN), which consists of the Ulysses, Near-Earth Asteroid Rendezvous, and Wind spacecraft. Radio observations wit…
ASCA Observation of the Quiescent X-Ray Counterpart to SGR 1627-41
Hurley, K.; Sugizaki, M.; Kouveliotou, C. +9 more
We present a 2-10 keV ASCA observation of the field around the soft gamma repeater SGR 1627-41. A quiescent X-ray source, whose position is consistent both with that of a recently discovered BeppoSAX X-ray source and with the Interplanetary Network localization for this soft gamma repeater, was detected in this observation. In 2-10 keV X-rays, the…
Langmuir Waves in the Vicinity of interplanetary Shocks and the Consequences for Type II Burst Models
MacDowall, R. J.; Thejappa, G.
The in situ wave data obtained by the Ulysses Unified Radio And Plasma wave experiment in the vicinity of a large number of interplanetary shocks show that Langmuir waves (1) are observed in only ~15% of the interplanetary shocks, (2) occur mostly in the upstream regions, and (3) are produced in the vicinity of both quasi-parallel Q∥ an…
Gamma-Ray Burst Arrival-Time Localizations: Simultaneous Observations by Ulysses, Pioneer Venus Orbiter, SIGMA, WATCH, and PHEBUS
Cline, T.; Hurley, K.; Sunyaev, R. +15 more
Between the launch of the Ulysses spacecraft in 1990 October and the entry of Pioneer Venus Orbiter (PVO) into the atmosphere of Venus in 1992 October, concurrent coverage by Ulysses, PVO, the WATCH experiments aboard the Granat and Eureca spacecraft, and the SIGMA and PHEBUS experiments aboard the Granat spacecraft was obtained for numerous gamma…