arXiv subjects

Ariel Perera

Publications and source records attributed to Ariel Perera.

4 recordsLinked to original sources

arXiv2026

A Multi-Mission Detection Framework for High-Energy Transients: Application to a 13-year Fermi/GBM and Swift/BAT Sample

The detection of faint high-energy transients is becoming increasingly important in time-domain and multi-messenger astronomy, particularly for identifying electromagnetic counterparts to binary neutron star mergers, high-energy neutrino events, and other weak transient phenomena. At present, the sensitivity of gamma-ray and hard X-ray searches is often limited by the detection threshold of individual instruments, leaving a population of faint transients inaccessible to single-mission analyses. To address this limitation, we develop a joint detection framework that combines trigger information from multiple detectors and assigns each candidate a joint association probability, $p_{\text{joint}}$, as a function of the individual detector signal-to-noise ratios. We apply this framework to archival Fermi/GBM and Swift/BAT rates data from 2013-2025. The method effectively separates coincident signals from accidental background associations, suppressing inconsistent coincidences while enhancing the significance of faint events observed by both instruments. We find that, under optimal conditions, a two-mission search can increase the accessible volume for short gamma-ray bursts by up to $60\%$. This framework provides a practical foundation for generalized multi-mission searches, enabling more sensitive exploration of the faint high-energy transient sky and improving the prospects for future multi-messenger discoveries.

astro-ph.HE↗

arXiv2026

A Coherent Search for New Galactic Magnetars using Fermi/GBM and follow-up Swift/BAT: 7 Candidates and a Large Burst Catalog

Galactic magnetars are a rare class of neutron stars with extreme magnetic fields, with only about 30 known sources. Their short hard X-ray and soft gamma-ray bursts provide an important channel for discovering magnetar activity. Wide-field instruments such as the Fermi Gamma-ray Burst Monitor (GBM) are well suited to detecting these bursts, but their broad localization uncertainties make it difficult to associate individual bursts with specific sources. Coded-aperture telescopes, in contrast, provide arcminute-scale localizations but have narrower fields of view. We search for previously unidentified magnetars and construct a magnetar burst catalog by combining a broad sample of short, soft triggers from our coherent GBM detection pipeline over 2013-2025 with targeted searches of archival Swift/BAT images. We develop a statistical association framework that uses BAT detections to localize GBM bursts to arcminute precision, together with a spatio-temporal clustering framework that associates poorly localized bursts with common sources. Together, these methods identify 1720 magnetar bursts, of which 1170 are confidently associated with 11 known magnetars. The remaining 550 bursts could not be assigned to specific sources. We identify seven candidate new magnetars through three complementary discovery channels. The catalog, composed of the associated bursts, extends to the lowest fluences observed by GBM. We also provide spectral and temporal analyses of the catalog. The new candidate sources provide targets for X-ray follow-up that could reveal previously unidentified Galactic magnetars. More broadly, this work demonstrates how combining instruments with complementary capabilities can maximize the scientific return of high-energy transient observations.

astro-ph.HE↗

arXiv2026

Expanding the Population of Short Gamma-Ray Transients with a Coherent Fermi/GBM Search. A 13-year catalog of short GRBs

In this paper, we present an archival search for short gamma-ray bursts (sGRBs) over 13 years (2013-2025) of Fermi/GBM data using a Poisson matched-filter pipeline that performs a fully coherent analysis across all detectors and energy channels, significantly improving sensitivity relative to the onboard triggering algorithms. A central component of the analysis is the empirical estimation of trigger significance using 'timeslided' data, allowing each candidate to be assigned a probability of astrophysical origin. We also developed a new parameter-estimation framework based on the Poisson matched filter, which uses the global structure of the detected event across spectral, temporal, and spatial parameter spaces. This enables us to systematically classify bursts and distinguish between GRBs, soft gamma repeaters, terrestrial gamma-ray flashes, and solar flares. We identify 568 new GRB candidates with $p_{\text{astro}}\geq0.9$ and thousands of magnetar bursts, significantly expanding the known short-transient population in GBM data. To further strengthen the significance of the GRB candidates, we performed a targeted follow-up search in Swift/BAT rate data. Applying the followup to all of our triggers - including triggers below the detection threshold yielded 1736 temporally coincident events with association probability above $90\%$. The resulting probabilistically ranked catalog substantially expands the population of short GRBs and magnetar flares detected in GBM data and provides a statistically robust framework for multimessenger searches.

astro-ph.HE↗

arXiv2025

A New Search Pipeline for Short Gamma Ray Bursts in Fermi/GBM Data -- A 50% Increase in the Number of Detections

In this paper, we present the development and the results of a new search pipeline for short gamma-ray bursts (sGRBs) in the publicly available data from the Gamma-Ray Burst Monitor (GBM) on board the Fermi satellite. This pipeline uses rigorous statistical methods that are designed to maximize the information extracted from the Fermi/GBM detectors. Our approach differs substantially from existing search efforts in several aspects: The pipeline includes the construction of template banks, Poisson matched filtering, background estimation, background misestimation correction, automatic routines to filter contaminants, statistical estimation of the signal location and a quantitative estimator of the signal probability to be of a cosmological, terrestrial, or solar origin. Our analysis also includes operating the pipeline on "time-slided" copies of the data, which allows exact significance assessment and $p_{\text{astro}}$ computation, akin to the state-of-the-art gravitational waves (GW) data analysis pipelines. Depending on the spectral properties of the bursts, our pipeline achieves a signal-to-noise ratio (SNR) improvement by a factor of 2 to 15 over the onboard GBM triggering algorithm. This enhancement increases the detectable volume for sGRBs and results in an approximate 50% increase in sGRB detections in the 2014 GBM dataset. As a further consequence of the sensitivity increase, we detect hundreds of soft gamma-ray flares of galactic origin. This improved sensitivity enhances the chances of detecting fainter, off-axis GRBs that would likely fall below the standard triggering thresholds. Applying this pipeline to the full GBM archive is expected to expand further the joint sGRB-GW detection volume.

astro-ph.HE↗