Search Publications
A Possible Cepheid-like Luminosity Estimator for the Long Gamma-Ray Bursts
Ramirez-Ruiz, Enrico; Hurley, Kevin; Reichart, Daniel E. +3 more
We present a possible Cepheid-like luminosity estimator for the long gamma-ray bursts based on the variability of their light curves. To construct the luminosity estimator, we use CGRO/BATSE data for 13 bursts, Wind/Konus data for five bursts, Ulysses/GRB data for one burst, and NEAR/XGRS data for one burst. Spectroscopic redshifts, peak fluxes, a…
Evidence for a Sudden Magnetic Field Reconfiguration in Soft Gamma Repeater 1900+14
Hurley, Kevin; Kouveliotou, Chryssa; Göǧüş, Ersin +5 more
We report the detection of large flux changes in the persistent X-ray flux of soft gamma repeater (SGR) 1900+14 during its burst active episode in 1998. Most notably, we find a factor of ~700 increase in the nonburst X-ray flux following the August 27 flare, which decayed in time as a power law. Our measurements indicate that the pulse fraction re…
The Giant Flare of 1998 August 27 from SGR 1900+14. I. An Interpretive Study of BeppoSAX and Ulysses Observations
Hurley, K.; Feroci, M.; Duncan, R. C. +1 more
The giant flare of 1998 August 27 from SGR 1900+14 was extraordinary in many ways: it was the most intense flux of gamma rays ever detected from a source outside our solar system; it was longer than any previously detected burst from a soft gamma repeater (SGR) in our Galaxy by more than an order of magnitude; and it showed a remarkable four-peake…
GRB 000418: A Hidden Jet Revealed
Berger, E.; Bloom, J. S.; Cline, T. +15 more
We report on optical, near-infrared, and centimeter radio observations of GRB 000418 that allow us to follow the evolution of the afterglow from 2 to 200 days after the γ-ray burst (GRB). In modeling these broadband data, we find that an isotropic explosion in a constant-density medium is unable to simultaneously fit both the radio and optical dat…
Multicolor Observations of the GRB 000926 Afterglow
Axelrod, T. S.; Price, P. A.; Harrison, F. A. +25 more
We present multicolor light curves of the optical afterglow of gamma-ray burst (GRB) 000926. Beginning ~1.5 days after the burst, the light curves of this GRB steepen measurably. The existence of such achromatic breaks is usually taken to be an important observational signature that the ejecta are not expanding isotropically but rather have a coll…
Multiwavelength Observations of the Soft Gamma Repeater SGR 1900+14 during Its 2001 April Activation
Hurley, K.; Kouveliotou, C.; Fender, R. P. +6 more
The soft gamma repeater SGR 1900+14 became active on 2001 April 18 after about 2 years of quiescence; it had remained at a very low state of activity since the fall of 1998, when it exhibited extraordinary flaring. We have observed the source in the gamma-rays and X-rays with Ulysses and Chandra and in the radio with MERLIN. We report here the con…
A Search for Early Optical Emission from Short- and Long-Duration Gamma-Ray Bursts
Hurley, Kevin; McKay, Tim; Kehoe, Robert +16 more
Gamma-ray bursts of short duration may harbor vital clues to the range of phenomena producing bursts. However, recent progress from the observation of optical counterparts has not benefited the study of short bursts. We have searched for early optical emission from six gamma-ray bursts using the telephoto array on the Robotic Optical Transient Sea…
The X-Ray Afterglow of GRB 000926 Observed by BeppoSAX and Chandra: A Mildly Collimated Fireball in a Dense Medium?
Piro, L.; Antonelli, L. A.; Frail, D. A. +8 more
We present X-ray observations of the afterglow of GRB 000926, performed around and after the break observed in the optical light curve 2 days after the burst. The steep X-ray light curve observed around the break confirms the presence of this feature in X-rays. However, the spectral and temporal properties are not consistent with a standard jet sc…
Hubble Space Telescope STIS Observations of GRB 000301C: CCD Imaging and Near-Ultraviolet MAMA Spectroscopy
Fruchter, Andrew S.; Hogg, David W.; Livio, Mario +24 more
We present Space Telescope Imaging Spectrograph observations of the optical transient (OT) counterpart of the γ-ray burster GRB 000301C obtained 5 days after the burst, on 2000 March 6. CCD clear-aperture imaging reveals a R~=21.50+/-0.15 source with no apparent host galaxy. An 8000 s, 1150 Å<λ<3300 Å near-ultraviolet MAMA prism spectrum sho…
Connecting the Sun and the Solar Wind: Comparison of the Latitudinal Profiles of Coronal and Ulysses Measurements of the Fast Wind
Habbal, Shadia Rifai; Woo, Richard
A quantitative comparison of the latitudinal profile of polarized brightness (pB) measurements nearest the Sun at 1.15 Rsolar by the Mauna Loa Solar Observatory K-Coronameter and Ulysses interplanetary measurements of the fast solar wind during its first south polar pass, at the declining phase of the solar cycle, is made for the first …