Gamma-ray Urgent Archiver for Novel Opportunities (GUANO): Swift/BAT event data dumps on demand to enable sensitive sub-threshold GRB searches

Abstract

We introduce a new capability of the Neil Gehrels Swift Observatory, to provide event data from the Burst Alert Telescope (BAT) on demand in response to transients detected by other instruments. These event data are not continuously available due to the large telemetry load, but are critical to recovering weak or sub-threshold GRBs that are not triggered onboard, such as the likely counterparts to GW-detected off-axis binary neutron star mergers. We show that the availability of event data can effectively increase the rate of detections, and arcminute localizations, of GRB 170817-like bursts by >400%. We describe a spacecraft commanding pipeline purpose built to enable this science; to our knowledge the first fully autonomous extremely-low-latency commanding of a space telescope for scientific purposes. This pipeline has been successfully run in its complete form since early 2020, and has resulted in the recovery of BAT event data for >700 externally triggered events to date (GWs, neutrinos, GRBs triggered by other facilities, FRBs), now running with a success rate of ~90%. We exemplify the utility of this new capability by using the resultant data to (1) set the most sensitive (8 sigma) upper limits of $8.1\times 10^{-8}$ erg cm${}^{-2}$ s${}^{-1}$ (14-195 keV) on prompt 1s duration short GRB-like emission within $\pm$ 15s of the unmodelled GW burst candidate S200114f, and (2) provide arcminute localizations for short GRB 200325A and other bursts. We show that using data from GUANO to localize GRBs discovered elsewhere, we can increase the net rate of arcminute localized GRBs by 10-20% per year. Along with the scientific yield of more sensitive searches for sub-threshold GRBs, the new capabilities designed for this project will enable further rapid response Target of Opportunity capabilities for Swift, and have implications for the design of future rapid-response space telescopes.

Submitted to AAS Journals. 16 pages, 11 figures. A live record of data recovered can be found at https://www.swift.psu.edu/guano/

References in corpus (7)

• The NumPy array: a structure for efficient numerical computation
• Gravitational Waves and Gamma-rays from a Binary Neutron Star Merger: GW170817 and GRB 170817A
• An Ordinary Short Gamma-Ray Burst with Extraordinary Implications: Fermi-GBM Detection of GRB 170817A
• Swift and NuSTAR observations of GW170817: detection of a blue kilonova
• Localization of Gamma-Ray Bursts using the Fermi Gamma-Ray Burst Monitor
• Temporal Variations of Strength and Location of the South Atlantic Anomaly as Measured by RXTE
• Investigating the nature of INTEGRAL Gamma-ray Bursts and sub-threshold triggers with Swift follow up

Cited by in corpus (29)

• A bright gamma-ray flare interpreted as a giant magnetar flare in NGC 253
• Rapid Spectral Variability of a Giant Flare from a Magnetar in NGC 253
• Identification of a Local Sample of Gamma-Ray Bursts Consistent with a Magnetar Giant Flare Origin
• First demonstration of early warning gravitational wave alerts
• Swift-XRT follow-up of gravitational wave triggers during the third aLIGO/Virgo observing run
• Search for Gravitational Waves Associated with Gamma-Ray Bursts Detected by Fermi and Swift During the LIGO-Virgo Run O3b
• Prospects for multi-messenger detection of binary neutron star mergers in the fourth LIGO-Virgo-KAGRA observing run
• Multiwavelength observations of Fast Radio Bursts
• The First Short GRB Millimeter Afterglow: The Wide-Angled Jet of the Extremely Energetic SGRB 211106A
• Swift/UVOT follow-up of Gravitational Wave Alerts in the O3 era
• Early Warnings of Binary Neutron Star Coalescence using the SPIIR Search
• Pulsar revival in neutron star mergers: multi-messenger prospects for the discovery of pre-merger coherent radio emission
• A search for the afterglows, kilonovae, and host galaxies of two short GRBs: GRB 211106A and GRB 211227A
• Limits on Fast Radio Burst-like Counterparts to Gamma-ray Bursts using CHIME/FRB
• Realistic observing scenarios for the next decade of early warning detection of binary neutron stars
• Harvesting BAT-GUANO with NITRATES (Non-Imaging Transient Reconstruction And TEmporal Search): Detecting and localizing the faintest GRBs with a likelihood framework
• Multi-wavelength and Multi-messenger Counterparts of Fast Radio Bursts
• Application of Deep Learning Methods for Distinguishing Gamma-Ray Bursts from Fermi/GBM TTE Data
• A matched-filter approach to radio variability and transients: searching for orphan afterglows in the VAST Pilot Survey
• Constraining Near-Simultaneous Radio Emission from Short Gamma-ray Bursts using CHIME/FRB
• Swift Multiwavelength Follow-up of LVC S200224ca and the Implications for Binary Black Hole Mergers
• FRB131104 Swift BAT data revisited: No evidence of a gamma-ray counterpart
• The Second Catalog of Interplanetary Network Localizations of Konus Short Duration Gamma-Ray Bursts
• Searching for Gravitational-Wave Counterparts using the Transiting Exoplanet Survey Satellite
• The RTApipe framework for the gamma-ray real-time analysis software development
• GRB 241105A: A test case for GRB classification and rapid r-process nucleosynthesis channels
• El-CID: A filter for Gravitational-wave Electromagnetic Counterpart Identification
• Limits on the hard X-ray emission from the periodic fast radio burst FRB 180916.J0158+65
• Searching for gravitational waves from compact binary mergers powering long gamma-ray bursts during LIGO-Virgo-KAGRA's O3 run