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Swift Education and Public Outreach
Goddard Space Flight Center Sonoma State University Education and Public Outreach

Swift Facts and FAQ

What is Swift?
What are the Swift mission goals?
How does Swift work?
How did Swift get its name?
How do we communicate with Swift?
Who makes public the data that Swift acquires?
What is the Swift Science Center?
What are the Swift mission details?
What are the specs on the Burst Alert System?
What are the specs on the X-Ray telescope?
What are the specs on the Ultraviolate/Optical telescope?
What is the timeline if a GRB is detected?


Question:What is Swift?

Answer: Swift is a first-of-its-kind multi-wavelength observatory dedicated to the study of gamma-ray burst (GRB) science. Its three instruments work together to observe GRBs and afterglows in the gamma-ray, X-ray, optical, and ultraviolet wavebands. Swift, part of NASA™s medium explorer (MIDEX) program, was developed by an international collaboration. It was launched into a low-Earth orbit on a Delta 7320 rocket on November 20th, 2004. In 8 months Swift has already observed 45 GRBs, and during its nominal 2-year mission is expected to observe more than 200 bursts, which will represent the most comprehensive study of GRB afterglows to date.


Question:What are the Swift mission goals?

Answer:

  • Determine the origin of gamma-ray bursts.
  • Classify gamma-ray bursts and search for new types.
  • Determine how the blastwave evolves and interacts with the surroundings.
  • Use gamma-ray bursts to study the early universe.
  • Perform a sensitive survey of the sky in the hard X-ray band.

Question:How does Swift work?

Answer: Swift has a complement of three co-aligned instruments for studying gamma-ray bursts and their afterglow: the Burst Alert Telescope (BAT), the Xray Telescope (XRT), and the Ultraviolet/Optical Telescope (UVOT). The largest instrument on-board Swift is the BAT, which can view approximately a sixth of the entire sky at one time. It will detect approximately 100 or more gamma-ray bursts per year. Within seconds of detecting a burst, the spacecraft will "swiftly" and autonomously repoint itself to aim the XRT and UVOT at the burst to enable high-precision X-ray and optical positions and spectra to be determined. The positions will then be relayed to the ground for use by a network of observers at other telescopes. Swift will determine redshifts for most of the bursts that it detects (allowing scientists to know how far away they are and how absolutely bright they are), and will also provide detailed multi-wavelength light curves for the duration of the afterglow (allowing scientists to probe the physical environment in which the event took place). Key data taken by Swift will be relayed to the ground in near real-time, allowing the GRB Coordinate Network (GCN) to immediately distribute it to the world via the internet for follow-up observations and study. Swift will also use the BAT to perform an all-sky survey of low-energy gamma-rays that will be significantly more sensitive than any previous survey.


Question:How did Swift get its name?

Answer: Swift, unlike most NASA satellites, it not an acronym. Instead Swift is named for a bird of the same name. This bird is special because it can change angles very quickly in mid-flight, like Swift will do. For more information on how Swift got its name visit this link to Goddard's Science Question of the Day about it.


Question:How do we communicate to Swift?

Answer: The Mission Operations Center (MOC) at Penn State University provides real-time command and control of the spacecraft and monitors the observatory, while also taking care of science and mission planning, Targets of Opportunity (ToO) handling, and data capture and accounting. The Italian Space Agency™s ground station at Malindi, Kenya provides the primary communications. Swift burst alerts and burst characteristics are relayed almost instantaneously through the NASA TDRSS space data link to the GCN for rapid distribution to the community.


Question:Who will make public the data that Swift acquires?

Answer: Swift data will be made available to the world via three different data centers located in the United States (the High Energy Astrophysics Science Archive Research Center, HEASARC), the UK (the UK Swift Science Data Center, UKSSDC), and Italy (the Italian Swift Archive Center, ISAC).


Question:What is the Swift Science Center?

Answer: The Swift Science Center (SSC) assists the science community in fully utilizing the Swift data. It is also responsible for coordinating the development of the data analysis tools for Swift data. The BAT instrument team and the Italian Swift Archive Center will develop data analysis tools for the BAT and XRT data respectively. The Swift Science Center is responsible for developing the UVOT tools.


Question:What are the Swift mission details?

Answer:

  • Launch Date: November 20th, 2004
  • Prime Mission Duration: 2 years
  • Launcher: Delta II (7320)
  • Orbit: LEO 600 km circular
  • Orbital Life: 7 years
  • Inclination: 22 degrees
  • Dimentions:18.5 feet tall x 17.75 feet wide.
  • Spacecraft Partner: Spectrum Astro
  • Peak Slew Rate: 50 degrees in < 75 seconds
  • Arrival: Within 3 arcmin of target
  • Operations and Pointing: Autonomous
  • Uplink/Downlink: Dual Path, 2 kbps GRB alert downlink and uplink real-time using TDRSS MA link, 2.25 Mbps data rat for store and dump using Malindi-ASI seven orbits per day

Question:What are the specs on the Burst Alert Telescope?

Answer:

  • Aperture: Coded Mask
  • Detecting Area: 5200 cm2
  • Detector: CdZnTe
  • Detector Operation: Photon Counting
  • Field of View: 2.0 sr (partially coded)
  • Detection Elements: 256 modules of 128 elements
  • Detector Size: 4mm x 4mm x 2mm
  • Telescope PSF: 17 arcminutes
  • Location Accuracy: 1-4 arcminutes
  • Energy Range: 15-150 keV
  • Burst Detection Rate: > 100 bursts/year

Question:What are the specs on the X-Ray Telescope?

Answer:

  • Telescope: Wolter I
  • Detector: XMM EPIC CCD
  • Effective Area: 135 cm2 at 1.5 keV
  • Detector Operation: Photon Counting, Integrated Imaging, and Rapid Timing
  • Field of View: 23.6 x 23.6 arcminutes
  • Detection Element: 600 x 600 pixels
  • Pixel Scale: 2.36 arcsec/pixel
  • Telescope PSF: 18 arcsec HPD at 1.5 keV
  • Location Accuracy: 3-5 arcseconds
  • Energy Range: 0.2-10 keV
  • Sensitivity: 2 x 10-14 ergs cm-2 s-1 in 104 sec

Question:What are the specs on the Ultraviolet/Optical Telescope?

Answer:

  • Telescope: Modified Ritchey-Chrétien
  • Aperture: 30 cm diameter
  • F-number: 12.7
  • Detector: Intensified CCD
  • Detector Operation: Photon Counting
  • Field of View: 17 x 17 arcminutes
  • Detection Element: 2048 x 2048 pixels
  • Telescope PSF: 0.9 arcsec at 350 nm
  • Location Accuracy: 0.3 arcseconds
  • Wavelength Range: 170 nm - 650 nm
  • Colors: 6
  • Spectral Resolution (Grisms): ?/?? ~ 200 at 400 nm
  • Sensitivity: B = 24 in white light in 1000 sec
  • Pixel Scale: 0.48 arcseconds
  • Bright Limit: mv = 7 mag

Question:What is the timeline of events that occur when a GRB is detected?

Answer:

  • 0s: GRB detection
  • 20s: Slew Begins/BAT approximate location distributed
  • ~ 50s: GRB acquired
  • 70s: XRT location distributed
  • 240s: UVOT finding chart distributed
  • 300s: XRT light curve distributed
  • 1200s: XRT spectrum distributed
  • ~ 60,000s: All automated observations complete (20,000 sec exposure)


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