Search for correlation between GRB’s detected by BeppoSAX and gravitational wave detectors EXPLORER and NAUTILUS

Abstract

Data obtained during five months of 2001 with the gravitational wave (GW) detectors EXPLORER and NAUTILUS were studied in correlation with the gamma ray burst data (GRB) obtained with the BeppoSAX satellite. During this period BeppoSAX was the only GRB satellite in operation, while EXPLORER and NAUTILUS were the only GW detectors in operation. No correlation between the GW data and the GRB bursts was found. The analysis, performed over 47 GRB's, excludes the presence of signals of amplitude h ≥ 1.2 × 10 −18 , with 95% probability, if we allow a time delay between GW bursts and GRB within ±400 s, and h ≥ 6.5 × 10 −19 , if the time delay is within ±5 s. The result is also provided in form of scaled likelihood for unbiased interpretation and easier use for further analysis.

Cumulative analysis of the association between the data of the gravitational wave detectors NAUTILUS and EXPLORER and the gamma ray bursts detected by BATSE and BeppoSAX

“…4 shows that both the average and median distributions are close to normal. This allows us to represent the sensitivity of the experiment as a function of h and to evaluate an upper limit, using the same approach followed in our previous GRB-GW coincidence analysis [13], based on the likelihood rescaled to its value for background alone (R function, called also relative belief update function [33]). In fact, in the Bayesian approach we are implicitly following, the likelihood has the role of modifying our knowledge according to the scheme posterior ∝ R × prior.…”

“…Cumulative data analysis techniques have been developed to detect a statistically significant association between GW signals and GRBs [8,9,10,11,12]. Using for the first time a cross-correlation method applied to the data of two GW detectors, EXPLORER and NAUTILUS, experimental upper limits were determined for the amplitude of the GW bursts associated with GRBs [13]. Analyzing the data for 47 GRBs detected by BeppoSAX, the presence of GW pulses of amplitude h ≥ 1.2 × 10 −18 was excluded with 95 % probability, within the time window of ± 400 s. Within the time window of ± 5 s, the upper limit was improved to h = 6.5 × 10 −19 .…”

SGR 1806-20 and the gravitational wave detectors EXPLORER and NAUTILUS

“…In the past, this method has been applied to study correlations between EXPLORER and NAUTILUS data and gammaray bursts [24,25]. It has been also used and developed in the second, third and fourth LIGO science run data analysis [26], and more recently, in the enlarged LIGO-Virgo collaboration for gamma-ray burst search [27].…”

“…The second algorithm regards the crosscorrelation function calculated between the EXPLORER and NAUTILUS data streams, as shown in Sec. V. Following previous methods [24][25][26][27], cumulative analyses are performed on the sample of 73 measurements, obtaining several mismatches of the order of 1% probability or less from the background. The statistical significance is evaluated on the basis of the local probability and binomial tests of the resulting loudest measurements.…”

Gravitational waves and gamma-ray bursts

“…LIGO and Virgo have been carrying out electromagnetically triggered searches for GWs (Abbott et al 2005(Abbott et al , 2007Acernese et al 2007;Abbott et al 2008b,a;Acernese et al 2008b;Abbott et al 2009a;Abadie et al 2010b;Abbott et al 2010;Abadie et al 2011Abadie et al , 2012 over the past decade (for bar detectors electromagnetically triggered searches, see e.g. Astone et al 1999Astone et al , 2002Astone et al , 2005Baggio et al 2005). The LIGO Scientific Collaboration operates two LIGO observatories in the U.S. along with the GEO600 detector (Grote & LIGO Scientific Collaboration 2010) in Germany.…”