38 research outputs found
Harvesting BAT-GUANO with NITRATES (Non-Imaging Transient Reconstruction And TEmporal Search): Detecting and localizing the faintest GRBs with a likelihood framework
The detection of the gravitational wave counterpart GRB 170817A,
underluminous compared to the cosmological GRB population by a factor of
10,000, motivates significant effort in detecting and localizing a dim, nearby,
and slightly off-axis population of short GRBs. Swift/BAT is the most sensitive
GRB detector in operation, and the only one that regularly localizes GRBs to
arcminute precision, critical to rapid followup studies. However, the utility
of BAT in targeted sub-threshold searches had been historically curtailed by
the unavailability of the necessary raw data for analysis. The new availability
of time-tagged event (TTE) data from the GUANO system (arXiv:2005.01751),
motivates renewed focus on developing sensitive targeted search analysis
techniques to maximally exploit these data. While computationally cheap, we
show that the typical coded-mask deconvolution imaging is limited in its
sensitivity due to several factors. We formalize a maximum likelihood framework
for the analysis of BAT data wherein signals are forward modelled through the
full instrument response, and -- coupled with the development of new response
models -- demonstrate its superior sensitivity to typical imaging via archival
comparisons, injection campaigns, and, after implementing as a targeted search,
a large number of low-latency GRB discoveries and confirmed arcminute
localizations to date. We also demonstrate independent localization of some
out-of-FOV GRBs for the first time. NITRATES's increased sensitivity boosts the
discovery rate of GRB 170817A-like events in BAT by a factor of at least
x, along with enabling joint analyses and searches with other GRB, GW,
neutrino, and FRB instruments. We provide public access to the response
functions and search pipeline code.Comment: Submitted to AAS Journals. 46 pages, 34 figures. Comments and
feedback are welcome. The codebase and instrument responses can be found at
https://github.com/Swift-BAT/NITRATE
The Gravitational Wave Treasure Map: A Tool to Coordinate, Visualize, and Assess the Electromagnetic Follow-Up of Gravitational Wave Events
We present the Gravitational Wave Treasure Map, a tool to coordinate,
visualize, and assess the electromagnetic follow-up of gravitational wave (GW)
events. With typical GW localization regions of hundreds to thousands of square
degrees and dozens of active follow-up groups, the pursuit of electromagnetic
(EM) counterparts is a challenging endeavor, but the scientific payoff for
early discovery of any counterpart is clear. With this tool, we provide a
website and API interface that allows users to easily see where other groups
have searched and better inform their own follow-up search efforts. A strong
community of Treasure Map users will increase the overall efficiency of EM
counterpart searches and will play a fundamental role in the future of
multi-messenger astronomy.Comment: 14 pages, 8 figures, Accepted to Ap
Scheduling Discovery in the 2020s
The 2020s will be the most data-rich decade of astronomy in history. As the scale and complexity of our surveys increase, the problem of scheduling becomes more critical. We must develop high-quality scheduling approaches, implement them as open-source software, and begin linking the typically separate stages of observation and data analysis
Scheduling Discovery in the 2020s
The 2020s will be the most data-rich decade of astronomy in history. As the scale and complexity of our surveys increase, the problem of scheduling becomes more critical. We must develop high-quality scheduling approaches, implement them as open-source software, and begin linking the typically separate stages of observation and data analysis