Search for gravitational-wave bursts in LIGO data at the Schenberg antenna sensitivity range

The Brazilian Mario Schenberg gravitational-wave detector was initially designed in the early 2000s and remained operational until 2016 when it was disassembled. To assess the feasibility of reassembling the Schenberg antenna, its capability to detect gravitational waves (GW) within its designed sensitivity parameters needs to be evaluated. Detection of significant signals would serve as a catalyst for rebuilding the detector. Although the antenna is currently disassembled, insights can be gleaned from the third observing run (O3) data of the LIGO detectors, given the similarities between Schenberg's ultimate sensitivity and the interferometers' sensitivity in the [3150-3260] Hz band. The search focused on signals lasting from milliseconds to seconds, with no assumptions about their morphology, polarization, and arrival sky direction. Data analysis was performed using the coherent WaveBurst pipeline in the frequency range between 512 Hz and 4096 Hz, specifically targeting signals with bandwidths overlapping the Schenberg frequency band. However, the O3 data did not yield statistically significant evidence of GW bursts. This null result allowed for the characterization of the search efficiency in identifying simulated signal morphologies and setting upper limits on the GW burst event rate as a function of strain amplitude. The current search, and by extension the advanced version of the Schenberg antenna (aSchenberg), can detect sources emitting isotropically 5 x 10-6M circle dot c2 in GWs from a distance of 10 kiloparsecs with a 50% detection efficiency at a false alarm rate of 1 per 100 years. Moreover, we revisited estimations of detecting f modes of neutron stars excited by glitches, setting the upper limit of the f-mode energy for the population of Galactic pulsars to similar to 8 x 10-8M circle dot c2 at 3205 Hz. Our simulations and the defined detection criteria suggest f modes are a very unlikely source of gravitational waves for the aSchenberg. Nevertheless, its potential in probing other types of gravitational wave short transients, such as those arising from supernova explosions, giant flares from magnetars, postmerger phase of binary neutron stars, or the inspiral of binaries of primordial black holes with subsolar masses, remains promising.