TheSwiftGamma‐Ray Burst Mission

Abstract

The Swift mission, scheduled for launch in 2004, is a multiwavelength observatory for gamma-ray burst (GRB) astronomy. It is a first-of-its-kind autonomous rapid-slewing satellite for transient astronomy and pioneers the way for future rapid-reaction and multiwavelength missions. It will be far more powerful than any previous GRB mission, observing more than 100 bursts yr À1 and performing detailed X-ray and UV/optical afterglow observations spanning timescales from 1 minute to several days after the burst. The objectives are to (1) determine the origin of GRBs, (2) classify GRBs and search for new types, (3) study the interaction of the ultrarelativistic outflows of GRBs with their surrounding medium, and (4) use GRBs to study the early universe out to z > 10. The mission is being developed by a NASA-led international collaboration. It will carry three instruments: a newgeneration wide-field gamma-ray (15-150 keV ) detector that will detect bursts, calculate 1 0 -4 0 positions, and trigger autonomous spacecraft slews; a narrow-field X-ray telescope that will give 5 00 positions and perform spectroscopy in the 0.2-10 keV band; and a narrow-field UV/optical telescope that will operate in the 170-600 nm band and provide 0B3 positions and optical finding charts. Redshift determinations will be made for most bursts. In addition to the primary GRB science, the mission will perform a hard X-ray survey to a sensitivity of $1 mcrab ($2 ; 10 À11 ergs cm À2 s À1 in the 15-150 keV band ), more than an order of magnitude better than HEAO 1 A-4. A flexible data and operations system will allow rapid follow-up observations of all types of high-energy transients, with rapid data downlink and uplink available through the NASA TDRSS system. Swift transient data will be rapidly distributed to the astronomical community, and all interested observers are encouraged to participate in follow-up measurements. A Guest Investigator program for the mission will provide funding for community involvement. Innovations from the Swift program applicable to the future include (1) a large-area gamma-ray detector using the new CdZnTe detectors, (2) an autonomous rapid-slewing spacecraft, (3) a multiwavelength payload combining optical, X-ray, and gamma-ray instruments, (4) an observing program coordinated with other ground-based and space-based observatories, and (5) immediate multiwavelength data flow to the community. The mission is currently funded for 2 yr of operations, and the spacecraft will have a lifetime to orbital decay of $8 yr.

BAT AGN Spectroscopic Survey. VIII. Type 1 AGN with Massive Absorbing Columns

“…The BASS team has analyzed both new and archival optical spectra for a large fraction (77%; 641/836) of the AGNs detected as part of the 70-month Swift Burst Alert Telescope (BAT; Gehrels et al 2004;Barthelmy et al 2005) catalog (Baumgartner et al 2013). Swift/BAT has been continuously surveying the entire sky at high energies (14-195keV); producing a nearly complete sample of AGNs up to the Compton thick limit (Ricci et al 2015) and reducing selection effects associated with host galaxy contamination and obscuration.…”

A VLA Study of High-redshift GRBs. I. Multiwavelength Observations and Modeling of GRB 140311A

“…GRB140311A was discovered by the Swift (Gehrels et al 2004) Burst Alert Telescope (BAT, Barthelmy et al 2005) on 2014 March 11 at 21:05:16 UT . The burst duration is T 90 = 71.4±9.5 s, with a fluence of F γ = (2.3±0.3)×10 −6 ergcm 2 (15-150 keV, 90% confidence; Krimm et al 2014).…”

Swift Observations of Novae

“…Although Swift (Gehrels et al 2004) was designed as a Gamma-Ray Burst Explorer, its rapid response capability and daily planning of its observing schedule also make it ideal for prompt follow-up and monitoring of transient sources such as novae. Using the co-aligned X-ray (XRT; Burrows et al 2005) and UV/Optical (UVOT; Roming et al 2005) telescopes, simultaneous light-curves over these bands can be obtained, allowing the investigation of broadband variability.…”