Search Publications
The Hubble Diagram to Redshift >6 from 69 Gamma-Ray Bursts
Schaefer, Bradley E.
One of the few ways to measure the properties of dark energy is to extend the Hubble diagram (HD) to higher redshifts with gamma-ray bursts (GRBs). GRBs have at least five properties (their spectral lag, variability, spectral peak photon energy, time of the jet break, and the minimum rise time) that have correlations to the luminosity of varying q…
Simultaneous Multiwavelength Observations of the Low/Hard State of the X-Ray Transient Source SWIFT J1753.5-0127
D'Avanzo, P.; Frontera, F.; Goldoni, P. +11 more
We report the results of simultaneous multiwavelength observations of the X-ray transient source SWIFT J1753.5-0127 performed with INTEGRAL, RXTE, NTT, REM, and VLA on 2005 August 10-12. The source, which underwent an X-ray outburst since 2005 May 30, was observed during the INTEGRAL Target of Opportunity program dedicated to new X-ray novae locat…
Prompt and Afterglow Emission Properties of Gamma-Ray Bursts with Spectroscopically Identified Supernovae
Ramirez-Ruiz, Enrico; Kouveliotou, Chryssa; Kaneko, Yuki +8 more
We present a detailed spectral analysis of the prompt and afterglow emission of four nearby long-soft gamma-ray bursts (GRBs 980425, 030329, 031203, and 060218) that were spectroscopically found to be associated with Type Ic supernovae and compare them to the general GRB population. For each event, we investigate the spectral and luminosity evolut…
MAGIC Upper Limits on the Very High Energy Emission from Gamma-Ray Bursts
Bastieri, D.; Ciprini, S.; Longo, F. +141 more
During its first data cycle, between 2005 and the beginning of 2006, the fast repositioning system of the MAGIC telescope allowed the observation of nine different gamma-ray bursts as possible sources of very high energy γ-rays. These observations were triggered by alerts from Swift, HETE-2, and INTEGRAL; they started as quickly as possible after …
On the Origin of Three Seismic Sources in the Proton-rich Flare of 2003 October 28
Zharkova, Valentina V.; Zharkov, Sergei I.
The three seismic sources, S1, S2, and S3, detected from MDI Dopplergrams using the time-distance (TD) diagram technique are presented with the locations, areas, and vertical and horizontal velocities of the visible wave displacements. Within the data cube of 120 Mm, the horizontal velocities and the wave propagation times vary slightly from sourc…
The WEBT Campaign on the Blazar 3C 279 in 2006
Lee, C. -U.; Nishiyama, S.; Mirabal, N. +77 more
The quasar 3C 279 was the target of an extensive multiwavelength monitoring campaign from 2006 January through April. An optical-IR-radio monitoring campaign by the Whole Earth Blazar Telescope (WEBT) collaboration was organized around target-of-opportunity X-ray and soft γ-ray observations with Chandra and INTEGRAL in 2006 mid-January, with addit…
Inverse Compton Scenarios for the TeV Gamma-Ray Emission of the Galactic Center
Hinton, J. A.; Aharonian, F. A.
The intense Compton cooling of ultrarelativistic electrons in the Klein-Nishina regime in radiation-dominated environments, such as that found in the Galactic center, may result in radically different electron spectra than those produced by synchrotron cooling. We explore these effects and their impact on the X-ray and γ-ray spectra produced in el…
Swift XRT Observation of 34 New INTEGRAL IBIS AGNs: Discovery of Compton-Thick and Other Peculiar Sources
Gehrels, N.; Bird, A. J.; Fiocchi, M. +7 more
For a significant number of the sources detected at high energies (>10 keV) by the INTEGRAL IBIS and Swift BAT instruments there is either a lack information about them in the 2-10 keV range or they are totally unidentified. Herein, we report on a sample of 34 IBIS AGNs or AGN candidate objects for which there is X-ray data in the Swift XRT arc…
GRO J1655-40: Early Stages of the 2005 Outburst
Smith, D. A.; Shrader, C. R.; Rupen, M. +4 more
The black hole X-ray binary transient GRO J1655-40 underwent an outburst beginning in early 2005. We present the results of our multiwavelength observational campaign to study the early outburst spectral and temporal evolution, which combines data from X-ray (RXTE and INTEGRAL), radio (VLA), and optical (ROTSE and SMARTS) instruments. During the r…
Hard X-Ray Emission of the Microquasar GX 339-4 in the Low/Hard State
Rodriguez, J.; Malzac, J.; Joinet, A. +4 more
We present the analysis of the high-energy emission of the Galactic black hole binary GX 339-4 in a low/hard state at the beginning of its 2004 outburst. The data from 273 ks of INTEGRAL observations, spread over 4 weeks, are analyzed, along with the existing simultaneous RXTE HEXTE and PCA data. During this period, the flux increases by a factor …