Publications (23)
Search for Gamma-Ray Burst Classes with the RHESSI Satellite
J. ÅÃpa, A. Mészáros, C. Wigger +3
A sample of 427 gamma-ray bursts (GRBs), measured by the RHESSI satellite, is studied statistically with respect to duration and hardness ratio. Standard statistical tests are used…
How the RHESSI gamma-ray burst measurements have been affected by the annealing procedure?
J. Ripa, P. Veres, C. Wigger
The performance of the nine RHESSI germanium detectors has been gradually deteriorating since its launch in 2002 because of radiation damage. To restore its former sensitivity, the…
The effect of annealing on the RHESSI gamma-ray detectors
P. Veres, J. Ripa, C. Wigger
The performance of nine RHESSI germanium detectors has been gradually deteriorating since its launch in 2002 because of radiation damage caused by passing through the Earth's radia…
A Comparison of Gamma-ray Burst Subgroups Measured by RHESSI and BATSE
J. Ripa, D. Huja, R. Hudec +2
A sample of almost 400 Gamma-ray bursts (GRBs) detected by the RHESSI satellite is studied statistically. We focus on GRB duration and hardness ratio and use the statistical chi^2…
X-Ray Polarization of Solar Flares Measured with Rhessi
E. Suarez-Garcia, W. Hajdas, C. Wigger +4
The degree of linear polarization in solar flares has not yet been precisely determined despite multiple attempts to measure it with different missions. The high energy range in pa…
Does the KARMEN time anomaly originate from a beam-correlated background?
F. Atchison, M. Daum, P. -R. Kettle +1
The time anomaly of neutrino events observed in the KARMEN detector at the ISIS facility is discussed. We show that beam-correlated neutron events are not completely suppressed by…
Statistical analysis of RHESSI GRB database
J. Ripa, R. Hudec, A. Meszaros +2
The Gamma-ray burst (GRB) database based on the data by the RHESSI satellite provides a unique and homogeneous database for future analyses. Here we present preliminary results on…
The RHESSI Satellite and Classes of Gamma-ray Bursts
J. Ripa, A. Meszaros, R. Hudec +2
Some articles based on the BATSE gamma-ray burst (GRB) catalog claim the existence of a third population of GRBs, besides long and short. In this contribution we wanted to verify t…
An exceptionally bright flare from SGR1806-20 and the origins of short-duration gamma-ray bursts
K. Hurley, S. E. Boggs, D. M. Smith +17
Soft-gamma-ray repeaters (SGRs) are galactic X-ray stars that emit numerous short-duration (about 0.1 s) bursts of hard X-rays during sporadic active periods. They are thought to b…
POLAR, a compact detector for Gamma Ray Bursts photon polarization measurements
N. Produit, F. Barao, S. Deluit +7
The design and the simulated performances of a compact detector dedicated to the measurement of GRB photon polarization is presented. Such a detector would permit to answer the que…
Rising indications for three gamma-ray burst groups
J. Ripa, D. Huja, A. Meszaros +1
Several papers were written about the gamma-ray burst (GRBs) groups. Our statistical study is based on the durations and hardness ratios of the Swift and RHESSI data.
Gamma-Ray Burst Polarization: Limits from RHESSI Measurements
C. Wigger, W. Hajdas, K. Arzner +2
Using the RHESSI satellite as a Compton polarimeter, a recent study claimed that the prompt emission of GRB021206 was almost fully linearly polarized. This was challenged by a subs…
A new analysis of the short-duration, hard-spectrum GRB 051103, a possible extragalactic SGR giant flare
K. Hurley, A. Rowlinson, E. Bellm +34
GRB 051103 is considered to be a candidate soft gamma repeater (SGR) extragalactic giant magnetar flare by virtue of its proximity on the sky to M81/M82, as well as its time histor…
Time resolved spectroscopy of GRB030501 using INTEGRAL
V. Beckmann, J. Borkowski, T. J. -L. Courvoisier +7
The Gamma-ray instruments on-board INTEGRAL offer an unique opportunity to perform time resolved analysis on GRBs. The imager IBIS allows accurate positiioning of GRBs and broad ba…
The Interplanetary Network Supplement to the BeppoSAX Gamma-Ray Burst Catalogs
K. Hurley, C. Guidorzi, F. Frontera +31
Between 1996 July and 2002 April, one or more spacecraft of the interplanetary network detected 787 cosmic gamma-ray bursts that were also detected by the Gamma-Ray Burst Monitor a…
Gamma-Ray Burst Classes Found in the RHESSI Data Sample
J. Ripa, C. Wigger, D. Huja +1
A sample of 427 gamma-ray bursts (GRBs), measured by the RHESSI satellite, is studied statistically to determine the number of GRB groups. Previous studies based on the BATSE Catal…
The Giant Flare of December 27, 2004 from SGR 1806-20
Steven E. Boggs, A. Zoglauer, E. Bellm +5
The giant flare of December 27, 2004 from SGR 1806-20 represents one of the most extraordinary events captured in over three decades of monitoring the gamma-ray sky. One measure of…
Observation of an unexpected hardening in the spectrum of GRB 021206
C. Wigger, O. Wigger, E. Bellm +1
GRB 021206 is one of the brightest GRBs ever observed. Its prompt emission, as measured by RHESSI, shows an unexpected spectral feature. The spectrum has a peak energy of about 700…
The KARMEN Time Anomaly: Search for a Neutral Particle of Mass 33.9 MeV in Pion Decay
M. Daum, M. Janousch, P-R. Kettle +5
We have searched for the pion decay pi^+ --> mu^+ X, where X is a neutral particle of mass 33.905 MeV. This process was suggested by the KARMEN Collaboration to explain an anomaly…
Integrating the Fermi Gamma-Ray Burst Monitor into the 3rd Interplanetary Network
K. Hurley, M. Briggs, V. Connaughton +35
We are integrating the Fermi Gamma-Ray Burst Monitor (GBM) into the Interplanetary Network (IPN) of Gamma-Ray Burst (GRB) detectors. With the GBM, the IPN will comprise 9 experimen…
A Search for Gamma-ray Burst Subgroups in the SWIFT and RHESSI Databases
J. Ripa, D. Huja, A. Meszaros +3
A sample of 286 gamma-ray bursts (GRBs) detected by the Swift satellite and 358 GRBs detected by the RHESSI satellite are studied statistically. Previously published articles, base…
The Interplanetary Network Supplement to the HETE-2 Gamma-Ray Burst Catalog
K. Hurley, J. -L. Atteia, C. Barraud +43
Between 2000 November and 2006 May, one or more spacecraft of the interplanetary network (IPN) detected 226 cosmic gamma-ray bursts that were also detected by the FREGATE experimen…
Spectral Analysis of GRBs Measured by RHESSI
C. Wigger, W. Hajdas, A. Zehnder +5
The Ge spectrometer of the RHESSI satellite is sensitive to Gamma Ray Bursts (GRBs) from about 40 keV up to 17 MeV, thus ideally complementing the Swift/BAT instrument whose sensit…