Editing Neil Gehrels Swift Observatory

{{Short description|NASA satellite of the Explorer program}}
{{Use American English|date=January 2020}}
{{Use dmy dates|date=December 2021}}
{{Infobox spaceflight
| name              = Neil Gehrels Swift Observatory
| names_list        = Explorer-84<br/>MIDEX-3<br/>Swift Gamma Ray Burst Explorer
| image             = Swift Observatory spacecraft model.png
| image_caption     = Neil Gehrels Swift Observatory
| image_size        = 300px

| mission_type      = [[Gamma-ray astronomy]]
| operator          = [[NASA]]{{\}}[[Pennsylvania State University]]
| COSPAR_ID         = 2004-047A
| SATCAT            = 28485
| website           = {{URL|https://swift.gsfc.nasa.gov/}}
| mission_duration  = 2 years (planned)<ref name="4_more_years">{{cite web|url=http://www.omitron.com/headlines/hl05.htm|title=NASA Swift Mission Extended for 4 More Years|publisher=Omitron|access-date=April 7, 2008|archive-url=https://web.archive.org/web/20080408131041/http://www.omitron.com/headlines/hl05.htm|archive-date=April 8, 2008}}</ref> <br/>{{time interval|20 November 2004 17:16|show=ymd|sep=,}} (''in progress'')

| spacecraft        = Explorer LXXXIV
| spacecraft_type   = Swift Gamma Ray Burst Explorer
| spacecraft_bus    = [[Star Bus|LEOStar-3]]
| manufacturer      = [[Spectrum Astro]]
| launch_mass       = {{cvt|1470|kg}}
| dry_mass          = {{cvt|613|kg}}
| payload_mass      = {{cvt|843|kg}}
| dimensions        = {{cvt|5.6|xx|5.4|m}}<ref name="swift-faq">{{cite web|url=http://swift.sonoma.edu/about_swift/general_faq.html|title=Swift Facts and FAQ|publisher=Sonoma State University|date=March 28, 2008|access-date=July 7, 2015|archive-date=24 June 2018|archive-url=https://web.archive.org/web/20180624050438/http://swift.sonoma.edu/about_swift/general_faq.html|url-status=dead}}</ref>
| power             = 1040 [[watt]]s

| launch_date       = 20 November 2004, 17:16:01 [[Coordinated Universal Time|UTC]]
| launch_rocket     = [[Delta II|Delta II 7320-10C]] (Delta 309)
| launch_site       = [[Cape Canaveral Space Force Station|Cape Canaveral]], [[Cape Canaveral Space Launch Complex 17|SLC-17A]]
| launch_contractor = [[Boeing Defense, Space & Security]]<ref name="launchkit2004">{{cite web|url=http://swift.gsfc.nasa.gov/news/2004/swift_presskit.pdf|title=Swift Explorer|publisher=NASA|date=November 1, 2004|access-date=December 18, 2016}} {{PD-notice}}</ref>

| entered_service   = 1 February 2005
| deactivated       = 
| last_contact      = 
| decay_date        =

| orbit_reference   = [[Geocentric orbit]]<ref name="Trajectory"/>
| orbit_regime      = [[Low Earth orbit]]
| orbit_periapsis   = {{cvt|585|km}}
| orbit_apoapsis    = {{cvt|604|km}}
| orbit_inclination = 20.60°
| orbit_period      = 96.60 minutes
| apsis             = gee

| instruments       = Burst Alert Telescope (BAT)<br/>UltraViolet Optical Telescope (UVOT)<br/>X-Ray Telescope (XRT)

| insignia          = Swift Gamma-Ray Burst Mission patch (transparent).png
| insignia_caption  = Swift Gamma Ray Burst Explorer
| insignia_size     = 175px

| programme         = '''Explorer program'''
| previous_mission  = [[GALEX]] (Explorer 83)
| next_mission      = [[THEMIS]] (Explorer 85-89)
}}

'''Neil Gehrels Swift Observatory''', previously called the '''Swift Gamma-Ray Burst Explorer''', is a [[NASA]] three-telescope [[space observatory]] for studying [[gamma-ray burst]]s (GRBs) and monitoring the afterglow in X-ray, and UV/visible light at the location of a burst.<ref name="Display"/> It was launched on 20 November 2004, aboard a [[Delta II]] [[launch vehicle]].<ref name="Trajectory"/> Headed by [[principal investigator]] [[Neil Gehrels]] until his death in February 2017, the mission was developed in a joint partnership between [[Goddard Space Flight Center]] (GSFC) and an international consortium from the United States, United Kingdom, and Italy. The mission is operated by [[Pennsylvania State University]] as part of NASA's [[Explorer program|Medium Explorer program]] (MIDEX).

The burst detection rate is 100 per year, with a sensitivity ~3 times fainter than the BATSE detector aboard the [[Compton Gamma Ray Observatory]]. The Swift mission was launched with a nominal on-orbit lifetime of two years. Swift is a NASA MIDEX (medium-class Explorer) mission. It was the third to be launched, following [[IMAGE (spacecraft)|IMAGE]] and [[Wilkinson Microwave Anisotropy Probe|WMAP]].<ref name="Display">{{cite web|url=https://nssdc.gsfc.nasa.gov/nmc/spacecraft/display.action?id=2004-047A|title=Display: SWIFT (Explorer 84) 2004-047A|publisher=NASA|date=28 October 2021|access-date=4 December 2021}} {{PD-notice}}</ref>

While originally designed for the study of gamma-ray bursts, Swift now functions as a general-purpose multi-wavelength observatory, particularly for the rapid followup and characterization of astrophysical transients of all types. As of 2020, Swift received 5.5 Target of Opportunity observing proposals per day, and observes ~70 targets per day, on average.<ref>{{cite web |url=https://www.swift.psu.edu/#name|title=Swift Mission Operations Center|publisher=PSU|date=December 27, 2021|access-date=December 27, 2021}} {{PD-notice}}</ref>

== Overview ==
Swift is a multi-[[wavelength]] [[space observatory]] dedicated to the study of [[gamma-ray burst]]s. Its three instruments work together to observe GRBs and their afterglows in the [[gamma-ray]], [[X-ray]], [[ultraviolet]], and [[Optics|optical]] wavebands.

Based on continuous scans of the area of the sky with one of the instrument's monitors, Swift uses [[momentum wheel]]s to autonomously slew into the direction of possible GRBs. The name "Swift" is not a mission-related acronym, but rather a reference to the instrument's rapid [[Slew (spacecraft)|slew]] capability, and the nimble [[swift (bird)|swift]] (bird of the same name).<ref>{{cite web |url=http://swift.gsfc.nasa.gov/docs/swift/swiftfaq.html#name|title=Swift Guest Investigator Program Frequently Asked Questions|publisher=NASA|date=September 26, 2007|access-date=May 2, 2009}} {{PD-notice}}</ref> All of Swift's discoveries are transmitted to the ground and those data are available to other observatories which join Swift in observing the GRBs.

In the time between GRB events, Swift is available for other scientific investigations, and scientists from universities and other organizations can submit proposals for observations.

The Swift Mission Operation Center (MOC), where commanding of the satellite is performed, is located in [[State College, Pennsylvania]] and operated by the [[Pennsylvania State University]] and industry subcontractors. The Swift main ground station is located at the [[Broglio Space Center]] near [[Malindi]] on the coast of eastern [[Kenya]], and is operated by the [[Italian Space Agency]] (ASI). The Swift Science Data Center (SDC) and archive are located at the Goddard Space Flight Center outside [[Washington, D.C.]] The United Kingdom Swift Science Data Centre is located at the [[University of Leicester]].

The Swift [[satellite bus]] was built by [[Spectrum Astro]], which was later acquired by [[General Dynamics Mission Systems|General Dynamics Advanced Information Systems]],<ref>{{cite news |url=https://www.eastvalleytribune.com/money/launch-of-a-satellite-made-by-the-general-dynamics-c4-systems-delayed/article_b2ec249e-9e6e-54b8-939d-937e80acc135.html|title=Launch of a satellite made by the General Dynamics C4 Systems delayed|publisher=East Valley Tribune|author=Taylor, Ed|date=October 6, 2011|access-date=April 27, 2023}}</ref> which was in turn acquired by [[Orbital Sciences Corporation]] (now [[Northrop Grumman Innovation Systems]]).

== Instruments ==
=== Burst Alert Telescope (BAT) ===
[[File:Swift's instrument - diagram of Burst Alert Telescope (BAT).jpg|thumb|Diagram of Burst Alert Telescope]]
The BAT detects GRB events and computes its coordinates in the sky. It covers a large fraction of the sky (over one [[steradian]] fully coded, three steradians partially coded; by comparison, the full sky solid angle is [[Solid angle|4π]] or about 12.6 steradians). It locates the position of each event with an accuracy of 1 to 4 [[Minute and second of arc|arcminutes]] within 15 [[second]]s. This crude position is immediately relayed to the ground, and some wide-field, rapid-slew ground-based telescopes can catch the GRB with this information. The BAT uses a [[coded aperture|coded-aperture mask]] of 52,000 randomly placed {{cvt|5|mm}} [[lead]] tiles, {{cvt|1|m}} above a detector plane of 32,768 {{cvt|4|mm}} [[Cadmium zinc telluride]] (CdZnTe) hard X-ray detector tiles; it is purpose-built for Swift. Energy range: 15–150 [[Electronvolt|keV]].<ref>{{cite web|url=http://swift.gsfc.nasa.gov/docs/swift/about_swift/bat_desc.html|title=Swift's Burst Alert Telescope (BAT)|publisher=NASA|date=February 28, 2006|access-date=May 2, 2009}} {{PD-notice}}</ref>

=== X-ray Telescope (XRT) ===
[[File:Swift pre-launch.jpg|thumb|Swift before launch]]
The XRT <ref>{{cite journal|title=The Swift X-Ray Telescope|journal=Space Science Reviews|first=David N.|last=Burrows|display-authors=et al.|volume=120|issue=3–4|pages=165–195|date=October 2005 |doi=10.1007/s11214-005-5097-2|bibcode=2005SSRv..120..165B|arxiv=astro-ph/0508071|s2cid=54003617}}</ref> can take images and perform [[spectroscopy|spectral analysis]] of the GRB afterglow. This provides more precise location of the GRB, with a typical error circle of approximately 2 [[Minute and second of arc|arcseconds]] radius. The XRT is also used to perform long-term monitoring of GRB afterglow light-curves for days to weeks after the event, depending on the brightness of the afterglow. The XRT uses a [[Wolter telescope|Wolter Type I X-ray telescope]] with 12 nested mirrors, focused onto a single MOS [[charge-coupled device]] (CCD) similar to those used by the [[XMM-Newton]] EPIC MOS cameras. On-board software allows fully automated observations, with the instrument selecting an appropriate observing mode for each object, based on its measured count rate. The telescope has an energy range of 0.2–10 keV.<ref>{{cite web|url=http://swift.gsfc.nasa.gov/docs/swift/about_swift/xrt_desc.html|title=Swift's X-Ray Telescope (XRT) |publisher=NASA|date=August 15, 2008|access-date=May 2, 2009}} {{PD-notice}}</ref>

=== Ultraviolet/Optical Telescope (UVOT) ===
[[File:M101 combined low.jpg|thumb|upright=1.0|left|UVOT's "[[first light (astronomy)|first light]]" image]]

After Swift has slewed towards a GRB, the [[Ultraviolet/Optical Telescope|UVOT]] is used to detect an optical afterglow. The UVOT provides a sub-arcsecond position and provides optical and ultra-violet photometry through lenticular filters and low resolution spectra (170–650&nbsp;nm) through the use of its optical and UV [[grism]]s. The UVOT is also used to provide long-term follow-ups of GRB afterglow lightcurves. The UVOT is based on the [[XMM-Newton]]'s Optical Monitor (OM) instrument, with improved optics and upgraded onboard processing computers.<ref>{{cite web |url=http://swift.gsfc.nasa.gov/docs/swift/about_swift/uvot_desc.html|title=Swift's Ultraviolet/Optical Telescope (UVOT)|publisher=NASA|date=December 14, 2006|access-date=May 2, 2009}} {{PD-notice}}</ref>

On 9 November 2011, UVOT photographed the asteroid [[(308635) 2005 YU55|2005 YU55]] as the [[asteroid]] made a close flyby of the [[Earth]].<ref>{{cite web|url=https://svs.gsfc.nasa.gov/vis/a010000/a010800/a010871/|title=Swift Captures Flyby of Asteroid 2005 YU55|publisher=NASA|date=November 11, 201|access-date=November 22, 2011|archive-date=5 March 2016|archive-url=https://web.archive.org/web/20160305021416/http://svs.gsfc.nasa.gov/vis/a010000/a010800/a010871/|url-status=dead}} {{PD-notice}}</ref>

On 3 June 2013, UVOT unveiled a massive ultraviolet survey of the nearby [[Magellanic Clouds]].<ref>{{cite web|url=https://www.nasa.gov/mission_pages/swift/bursts/magellanic-uv.html|title=NASA's Swift Produces Best Ultraviolet Maps of the Nearest Galaxies|publisher=NASA|date=June 3, 2013}} {{PD-notice}}</ref>

In August 2017, UVOT imaged UV emissions from gravitational wave event [[GW170817]] detected by LIGO & Virgo detectors.<ref>[https://www.nasa.gov/press-release/nasa-missions-catch-first-light-from-a-gravitational-wave-event ''NASA Missions Catch First Light from a Gravitational-Wave Event'' 2017] {{PD-notice}}</ref><ref name="Evans2017"/>

== Experiments ==
[[File:Model of the Swift satellite.jpg|thumb|right|A model of the satellite]]
=== Burst Alert Telescope (BAT) ===
BAT (Burst Alert Telescope) is a gamma ray telescope, built by NASA's Goddard Space Flight Center, uses a coded aperture to locate the source. The software to locate the source is provided by the [[Los Alamos National Laboratory]] (LANL). The CdZnTe detector of {{cvt|5200|cm2}} area, consisting of 32,500 units of {{cvt|4|xx|4|xx|2|mm}}, can pin-point the location of sources within 1.4 arcminutes. The energy range is 15-150 keV.<ref name="Experiment1">{{cite web|url=https://nssdc.gsfc.nasa.gov/nmc/experiment/display.action?id=2004-047A-01|title=Experiment: Burst Alert Telescope (BAT)|publisher=NASA|date=28 October 2021 |access-date=4 December 2021}} {{PD-notice}}</ref>

=== Ultraviolet/Optical Telescope (UVOT) ===
UVOT (Ultraviolet/Optical Telescope) monitors the afterglow in ultraviolet and visible light, and locates the source at an accuracy of one arcsecond. Its aperture is {{cvt|30|cm}}, with an f-number equal to 12.7, and is backed by 2048 x 2048 [[photon]] counting CCD [[pixel]]s. The source location accuracy is better than one arcsecond.<ref name="Experiment3">{{cite web |url=https://nssdc.gsfc.nasa.gov/nmc/experiment/display.action?id=2004-047A-03 |title=Experiment: Ultraviolet/Optical Telescope (UVOT)|publisher=NASA|date=28 October 2021|access-date=4 December 2021}} {{PD-notice}}</ref>

=== X-Ray Telescope (XRT) ===
XRT (X-Ray Telescope) aims at the source more accurately, and monitors the afterglow in X-rays. It was built jointly by the [[Pennsylvania State University]] (PSU), the [[Brera Astronomical Observatory]], Italy, and the [[University of Leicester]], United Kingdom. It has a detector of area {{cvt|135|cm2}} consisting of 600 x 600 pixels, and covers the energy range of 0.2-10 keV. It can locate the afterglow source at an accuracy of four arcseconds.<ref name="Experiment2">{{cite web|url=https://nssdc.gsfc.nasa.gov/nmc/experiment/display.action?id=2004-047A-02|title=Experiment: X-Ray Telescope (XRT) |publisher=NASA|date=28 October 2021|access-date=4 December 2021}} {{PD-notice}}</ref>

== Mission goals ==
The Swift mission has four key scientific objectives:
* To determine the origin of GRBs. There seem to be at least two types of GRBs, only one of which can be explained with a [[hypernova]], creating a gamma-ray beam. More data is needed to explore other explanations
* To use GRBs to expand understanding of the young [[universe]]. GRBs seem to take place at "cosmological distances" of many millions or billions of [[light-years]], which means they can be used to probe the distant, and therefore young, cosmos
* To conduct an all-sky survey which will be more sensitive than any previous one, and will add significantly to scientific knowledge of astronomical X-ray sources. Thus, it could also yield unexpected results
* To serve as a general purpose gamma-ray/X-ray/optical observatory platform, performing rapid "target of opportunity" observations of many transient astrophysical phenomena, such as [[supernova]]

== Mission history ==
[[File:Animation of Swift Observatory orbit around Earth.gif|thumb|upright=1.0|left|Animation of Swift Observatory's orbit around Earth, Earth is not shown.]]

Swift was launched on 20 November 2004, at 17:16:01 [[Coordinated Universal Time|UTC]] aboard a [[Delta II]] 7320-10C from [[Cape Canaveral Space Force Station|Cape Canaveral Air Force Station]] and reached a near-perfect orbit of {{cvt|585|xx|604|km}} [[altitude]], with an [[Orbital inclination|inclination]] of 20.60°.<ref name="Trajectory">{{cite web |url=https://nssdc.gsfc.nasa.gov/nmc/spacecraft/displayTrajectory.action?id=2004-047A|title=Trajectory: Swift (Explorer 84) 2004-047A|publisher=NASA|access-date=January 14, 2018}} {{PD-notice}}</ref>

On 4 December 2004, an anomaly occurred during instrument activation when the Thermo-Electric Cooler (TEC) Power Supply for the X-Ray Telescope did not turn on as expected. The XRT Team at University of Leicester and Pennsylvania State University were able to determine on 8 December 2004 that the XRT would be usable even without the TEC being operational. Additional testing on 16 December 2004 did not yield any further information as to the cause of the anomaly.

On 17 December 2004 at 07:28:30 UTC, the Swift Burst Alert Telescope (BAT) triggered and located on board an apparent gamma-ray burst during launch and early operations.<ref>{{cite web |url=http://gcn.gsfc.nasa.gov/other/041217.gcn3|title=GRB041217: The First GRB Located On-Board Swift|publisher=NASA|date=December 17, 2004|access-date=May 2, 2009}} {{PD-notice}}</ref> The spacecraft did not autonomously slew to the burst since normal operation had not yet begun, and autonomous slewing was not yet enabled. Swift had its first GRB trigger during a period when the autonomous slewing was enabled on 17 January 2005, at about 12:55 UTC. It pointed the XRT telescope to the on-board computed coordinates and observed a bright X-ray source in the field of view.<ref>{{cite web |url=http://gcn.gsfc.nasa.gov/other/050117.gcn3|title=GRB050117: Swift XRT Position|publisher=NASA|date=January 17, 2005|access-date=July 7, 2015}} {{PD-notice}}</ref>

On 1 February 2005, the mission team released the [[First light (astronomy)|first light]] picture of the UVOT instrument and declared Swift operational.

By May 2010, Swift had detected more than 500 GRBs.<ref>{{cite web|url=http://www.nasa.gov/mission_pages/swift/bursts/500th.html|title=NASA's Swift Catches 500th Gamma-ray Burst|publisher=NASA|date=April 19, 2010|access-date=October 10, 2016}} {{PD-notice}}</ref>

By October 2013, Swift had detected more than 800 GRBs.<ref>{{cite web|url=http://swift.gsfc.nasa.gov/archive/grb_table/stats/|title=Swift GRB Table Stats|publisher=NASA|access-date=November 10, 2013 |archive-url=https://web.archive.org/web/20131110040640/http://swift.gsfc.nasa.gov/archive/grb_table/stats/|archive-date=November 10, 2013}} {{PD-notice}}</ref>

On 27 October 2015, Swift detected its 1,000th GRB, an event named GRB 151027B and located in the constellation [[Eridanus (constellation)|Eridanus]].<ref name="nasa20151106">{{cite web |url=http://www.nasa.gov/feature/goddard/nasas-swift-spots-its-thousandth-gamma-ray-burst|title=NASA's Swift Spots its Thousandth Gamma-ray Burst|publisher=NASA|date=November 6, 2015|access-date=October 10, 2016}} {{PD-notice}}</ref>

On 10 January 2018, NASA announced that the Swift spacecraft had been renamed the Neil Gehrels Swift Observatory in honor of mission PI [[Neil Gehrels]], who died in early 2017.<ref name="spacenews20180111">{{cite news|url=http://spacenews.com/nasa-renames-swift-mission-after-astronomer-neil-gehrels/|title=NASA renames Swift mission after astronomer Neil Gehrels|publisher=SpaceNews |first=Jeff|last=Foust|date=January 11, 2018|access-date=January 13, 2018}}</ref><ref>{{cite news|url=https://www.space.com/39349-swift-observatory-name-change.html|title=NASA Renames Swift Observatory in Honor of Late Principal Investigator|publisher=Space.com|first=Calla|last=Cofield|date=January 10, 2018|access-date=July 10, 2018}}</ref>

Swift entered safe mode on March 15, 2024 (after the 2nd of 4 gyroscopes failed) and was not conducting science. A software patch for two-gyroscope mode was developed, uplinked and tested in April 2024, and Swift returned to nominal operations at that point.<ref>{{Cite web |title=The Neil Gehrels Swift Observatory |url=https://swift.gsfc.nasa.gov/ |access-date=2024-03-22 |website=swift.gsfc.nasa.gov}}</ref>

== Notable detections ==
[[File:GRB 080319B.jpg|thumb|upright=1.0|right|[[GRB 080319B]], one of the brightest astronomical events ever detected, seen in X-ray and visible/UV light.]]
[[File:GRB 151027B in X-ray, UV and visible light.jpg|thumb|upright=1.0|right|GRB 151027B, the 1000th GRB detected by Swift.]]
[[File:GRBs detected by Swift, 2004-2015.jpg|thumb|upright=1.0|right|All-sky map of GRBs detected by Swift between 2004 and 2015.]]
[[File:PIA21076 Brown Dwarf Microlensing (Illustration), Figure 1.jpg|thumb|upright=1.0|right|Illustration of a brown dwarf combined with a graph of light curves from OGLE-2015-BLG-1319: Ground-based data (grey), Swift (blue), and Spitzer (red)]]

* 9 May 2005: Swift detected [[GRB 050509B]], a burst of gamma rays that lasted one-twentieth of a second. The detection marked the first time that the accurate location of a short-duration gamma-ray burst had been identified and the first detection of X-ray afterglow in an individual short burst.<ref>{{cite news|url=http://news.bbc.co.uk/2/hi/science/nature/4537905.stm|title=Blast hints at black hole birth |publisher=BBC News|first=David|last=Whitehouse|date=May 11, 2005|access-date=July 12, 2011}}</ref><ref>{{cite press release|url=http://www.berkeley.edu/news/media/releases/2005/05/31_shortburst.shtml |title=Astronomers hot on the trail of nature's exotic flashers|publisher=University of California, Berkeley|first=Joshua|last=Bloom|date=May 31, 2005|access-date=July 7, 2015}}</ref>
* 4 September 2005: Swift detected [[GRB 050904]] with a [[redshift]] value of 6.29 and a duration of 200 seconds (most of the detected bursts last about 10 seconds). It was also found to be the most distant yet detected, at approximately 12.6 billion [[light-year]]s.
* 18 February 2006: Swift detected [[GRB 060218]], an unusually long (about 2000 seconds) and nearby (about 440 million light-years) burst, which was unusually dim despite its close distance, and may be an indication of an imminent [[supernova]].
* 14 June 2006: Swift detected [[GRB 060614]], a burst of gamma rays that lasted 102 seconds in a distant galaxy (about 1.6 billion light-years). No supernova was seen following this event (and [[GRB 060505]] to deep limits) leading some to speculate that it represented a new class of progenitors. Others suggested that these events could have been massive star deaths, but ones which produced too little radioactive [[Isotopes of nickel|<sup>56</sup>Ni]] to power a supernova explosion.
* 9 January 2008: Swift was observing a supernova in [[NGC 2770]] when it witnessed an X-ray burst coming from the same galaxy. The source of this burst was found to be the beginning of another supernova, later called [[SN 2008D]]. Never before had a supernova been seen at such an early stage in its evolution. Following this stroke of luck (position, time, most appropriate instruments), astronomers were able to study in detail this [[Type Ib and Ic supernovae|Type Ibc supernova]] with the [[Hubble Space Telescope]], the [[Chandra X-ray Observatory]], the [[Very Large Array]] in [[New Mexico]], the [[Gemini North]] telescope in [[Hawaii]], [[Gemini South]] in Chile, the [[Keck I]] telescope in Hawaii, the {{cvt|1.3|m}} PAIRITEL telescope at [[Mount Hopkins (California)|Mount Hopkins]], the [[Hale Telescope|200-inch]] and {{cvt|60|in}} telescopes at the [[Palomar Observatory]] in [[California]], and the {{cvt|3.5|m}} telescope at the [[Apache Point Observatory]] in New Mexico. The significance of this supernova was likened by discovery team leader [[Alicia Soderberg]] to that of the [[Rosetta Stone]] for egyptology.<ref>{{cite press release|url=http://www.nasa.gov/mission_pages/swift/bursts/swift_supernova.html|title=NASA's Swift Satellite Catches a Star Going "Kaboom!"|publisher=NASA|date=May 21, 2008|access-date=May 2, 2009}} {{PD-notice}}</ref>
* 8 and 13 February 2008: Swift provided critical information about the nature of [[Hanny's Voorwerp]], mainly the absence of an ionizing source within the Voorwerp or in the neighboring [[IC 2497]].
* 19 March 2008: Swift detected [[GRB 080319B]], a burst of gamma rays amongst the brightest celestial objects ever witnessed. At 7.5 billion [[light-year]]s, ''Swift'' established a new record for the farthest object (briefly) visible to the naked eye. It was also said to be 2.5 million times intrinsically brighter than the previous [[SN 2005ap|brightest accepted supernova (SN 2005ap)]]. ''Swift'' observed a record four GRBs that day, which also coincided with the death of noted science-fiction writer [[Arthur C. Clarke]].<ref>{{cite web|url=http://www.nasa.gov/centers/goddard/news/topstory/2008/brightest_grb.html |title=NASA Satellite Detects Naked-Eye Explosion Halfway Across Universe|publisher=NASA|date=March 20, 2008|access-date=May 2, 2009}} {{PD-notice}}</ref>
* 13 September 2008: Swift detected [[GRB 080913]], at the time the most distant GRB observed (12.8 billion light-years) until the observation of [[GRB 090423]] a few months later.<ref>{{cite news |url=http://www.universetoday.com/2009/10/28/more-observations-of-grb-090423-the-most-distant-known-object-in-the-universe/|title=More Observations of GRB 090423, the Most Distant Known Object in the Universe |publisher=Universe Today|first=Nancy|last=Atkinson|date=October 28, 2009|access-date=February 23, 2010}}</ref><ref name='NASA'>{{cite web|url=http://www.nasa.gov/mission_pages/swift/bursts/farthest_grb.html |title=NASA's Swift Catches Farthest Ever Gamma-Ray Burst|publisher=NASA|first=Robert|last=Garner|date=September 19, 2008|access-date=November 3, 2008}} {{PD-notice}}</ref>
* 23 April 2009: Swift detected [[GRB 090423]], the most distant cosmic explosion ever seen at that time, at 13.035 billion light-years. In other words, the universe was only 630 million years old when this burst occurred.<ref>{{cite web|url=http://www.nasa.gov/mission_pages/swift/bursts/cosmic_record.html|title=New Gamma-Ray Burst Smashes Cosmic Distance Record|publisher=NASA|first=Francis|last=Reddy|date=April 28, 2009|access-date=May 2, 2009}} {{PD-notice}}</ref>
* 29 April 2009: Swift detected [[GRB 090429B]], which was found by later analysis published in 2011 to be 13.14 billion light-years distant (approximately equivalent to 520 million years after the Big Bang), even farther than GRB 090423.<ref name='BBC News'>{{cite news|url=https://www.bbc.co.uk/news/science-environment-13539914|title=Cosmic distance record "broken"|publisher=BBC News|first=Jonathan |last=Amos|date=May 25, 2011|access-date=May 25, 2011}}</ref>
* 16 March 2010: Swift tied its record by again detecting and localizing four bursts in a single day.
* 13 April 2010: Swift detected its 500th GRB.<ref>{{cite web|url=http://www.nasa.gov/mission_pages/swift/bursts/500th.html|title=NASA's Swift Catches 500th Gamma-ray Burst|publisher=NASA|first=Francis |last=Reddy|date=April 19, 2010|access-date=June 17, 2011}} {{PD-notice}}</ref>
* 28 March 2011: Swift detected Swift J1644+57 which subsequent analysis showed to possibly be the signature of a star being disrupted by a black hole or the ignition of an active galactic nucleus.<ref>{{cite news|url=http://www.huffingtonpost.com/2011/06/16/black-hole-eats-star_n_878317.html|title=Black Hole Devours Star: Source Of Mysterious Flash In Distant Galaxy Determined|newspaper=The Huffington Post |first=Alicia|last=Chang|date=June 16, 2011|access-date=June 17, 2011}}</ref> "This is truly different from any explosive event we have seen before", said [[Joshua Bloom]] of the [[University of California, Berkeley]], the lead author of the study published in the June issue of ''[[Science (journal)|Science]]''.<ref>{{cite news|url=http://www.cosmosmagazine.com/news/4428/black-hole-eats-star-produce-gamma-ray-flash|title=Black hole eats star, triggers gamma-ray flash|publisher=Cosmos (Australian magazine)|agency=Agence France-Presse|date=June 17, 2011|access-date=June 17, 2011|url-status=dead|archive-url=https://web.archive.org/web/20110618164403/http://www.cosmosmagazine.com/news/4428/black-hole-eats-star-produce-gamma-ray-flash|archive-date=June 18, 2011}}</ref>
* 16 and 17 September 2012: BAT triggered two times on a previously unknown hard X-ray source, named [[Sw J1745-26]], a few degrees from the [[Galactic Center]]. The outburst, produced by a rare X-ray nova, announced the presence of a previously unknown stellar-mass black hole undergoing a dramatic transition from the low/hard to the high/soft state.<ref>{{cite web |url=http://www.nasa.gov/mission_pages/swift/bursts/new-black-hole.html|title=NASA's Swift Satellite Discovers a New Black Hole in our Galaxy|publisher=NASA|first=Francis|last=Reddy|date=October 5, 2012 |access-date=November 10, 2013}} {{PD-notice}}</ref><ref>{{cite web|url=http://www.astronomerstelegram.org/?read=4383|title=Swift J174510.8-262411 (to be known as Sw J1745-26): 0.5 Crab and rising|newspaper=The Astronomer's Telegram|first=Boris|last=Sbarufatti|date=September 17, 2012|access-date=November 10, 2013}}</ref><ref>{{cite web|url=http://www.astronomerstelegram.org/?read=4450|title=Swift J174510.8-262411 in the hard intermediate state|newspaper=The Astronomer's Telegram|first=Tomaso|last=Belloni|date=October 3, 2012|access-date=November 10, 2013}}</ref>
* 2013:  Discovery of ultra-long class of gamma-ray bursts
* 24 April 2013: Swift detected an X-ray flare from the Galactic Center. This proved not to be related to [[Sgr A*]] but to a previously unsuspected [[magnetar]]. Later observations by the [[NuSTAR]] and the [[Chandra X-ray Observatory]] confirmed the detection.<ref>{{cite news|url=http://www.skyandtelescope.com/news/A-Cosmic-Sleight-of-Hand-206975291.html|title=A Cosmic Sleight of Hand|publisher=Sky & Telescope|first=Monica|last=Young|date=May 10, 2013|access-date=November 10, 2013|url-status=dead|archive-url=https://archive.today/20130630092246/http://www.skyandtelescope.com/news/A-Cosmic-Sleight-of-Hand-206975291.html|archive-date=June 30, 2013}}</ref>
* 27 April 2013: Swift detected the "shockingly bright" Gamma-ray burst [[GRB 130427A]]. Observed simultaneously by the [[Fermi Gamma-ray Space Telescope]], it is one of the five closest GRBs detected and one of the brightest seen by either space telescope.<ref>{{cite web|url=http://www.nasa.gov/topics/universe/features/shocking-burst.html|title=NASA's Fermi, Swift See 'Shockingly Bright' Burst|publisher=NASA |first=Francis|last=Reddy|date=May 3, 2013|access-date=November 10, 2013}} {{PD-notice}}</ref>
* 3 June 2013:  Evidence for kilonova emission in short GRB
* 23 April 2014: Swift detected the strongest, hottest, and longest-lasting sequence of stellar flares ever seen from a [[DG Canum Venaticorum|nearby red dwarf star]]. The initial blast from this record-setting series of explosions was as much as 10,000 times more powerful than the largest solar flare ever recorded.<ref name="nasa20140930">{{cite web|url=http://www.nasa.gov/content/goddard/nasas-swift-mission-observes-mega-flares-from-a-mini-star/|title=NASA's Swift Mission Observes Mega Flares from a Mini Star|publisher=NASA|date=September 30, 2014|access-date=March 19, 2015}} {{PD-notice}}</ref>
* 3 May 2014: Detection of a UV Pulse from an iPTF discovered young Type Ia SN
* June–July 2015: The [[brown dwarf]] OGLE-2015-BLG-1319 was discovered using the [[gravitational microlensing]] detection method in a joint effort between Swift, [[Spitzer Space Telescope]], and the ground-based [[Optical Gravitational Lensing Experiment]], the first time two space telescopes have observed the same microlensing event. This method was possible because of the large separation between the two spacecraft: Swift is in [[low Earth orbit]] while Spitzer is more than one [[astronomical unit|AU]] distant in an Earth-trailing [[heliocentric orbit]]. This separation provided significantly different perspectives of the brown dwarf, allowing for constraints to be placed on some of the object's physical characteristics.<ref name="nasa20161110">{{cite web|url=http://www.jpl.nasa.gov/news/news.php?feature=6673|title=NASA Space Telescopes Pinpoint Elusive Brown Dwarf|publisher=NASA|date=November 10, 2016|access-date=December 18, 2016}} {{PD-notice}}</ref>
* 27 October 2015: Swift detected its 1000th gamma-ray burst, GRB 151027B.<ref name="nasa20151106"/>
* 18 August 2017: Swift discovers UV emission from the [[kilonova]] [[AT 2017gfo]], the electromagnetic counterpart to [[GW170817]].<ref name="Evans2017">{{cite journal|title=Swift and NuSTAR observations of GW170817: detection of a blue kilonova|arxiv=1710.05437|first=P. A.|last=Evans|journal=Science|date=October 16, 2017|volume=358|issue=6370|pages=1565–1570|doi=10.1126/science.aap9580 |pmid=29038371|bibcode=2017Sci...358.1565E|s2cid=4028270}}</ref>
* 23 September 2017: Swift is the first to identify {{nowrap|TXS 0506+056}} as the possible source of the IceCube-170922A extremely high energy (EHE) [[neutrino]]s.<ref name="gnc20170926">{{cite web |url=https://gcn.gsfc.nasa.gov/gcn/gcn3/21930.gcn3|title=IceCube-170922A: Swift-XRT observations|work=GCN Circulars|first1=A.|last1=Keivani|first2=P. A.|last2=Evans|first3=J. A.|last3=Kennea|first4=D. B. |last4=Fox|first5=D. F.|last5=Cowen|first6=J. P.|last6=Osborne|first7=F. E.|last7=Marshall|display-authors=1|date=September 26, 2017|access-date=April 19, 2018}} {{PD-notice}}</ref>
* 14 January 2019: Swift discovers the most powerful observed gamma-ray burst, [[GRB 190114C]], reaching [[teraelectronvolt]] energies.<ref>{{cite web|url=http://www.nasa.gov/feature/goddard/2019/nasa-s-fermi-swift-missions-enable-a-new-era-in-gamma-ray-science|title=NASA's Fermi, Swift Missions Enable a New Era in Gamma-ray Science|publisher=NASA|date=November 20, 2019|access-date=November 26, 2019}} {{PD-notice}}</ref>
* 09 October 2022: Swift discovers, simultaneously with Fermi, [[GRB 221009A]], one of the closest GRBs ever detected and the brightest ever detected.

== See also ==
{{Portal|Spaceflight}}
* [[List of gamma-ray bursts]]
* [[List of X-ray space telescopes]]
* [[GRB 221009A]]
* [[Space Variable Objects Monitor]] (SVOM), the planned successor of Swift

== References ==
{{Reflist}}

== Further reading ==
* {{cite news|url=https://www.newscientist.com/article/dn7237|title=Swift measures distance to gamma-ray bursts|publisher=New Scientist|first=Maggie|last=McKee|date=April 6, 2005}}

== External links ==
{{Commons category|Swift Gamma-Ray Burst Mission}}
* [https://swift.gsfc.nasa.gov/ Swift website] by NASA/GSFC
* [http://www.swift.ac.uk/ Swift website] by the UK Swift Science Data Centre
* [http://www.swift.psu.edu/ Swift website] by Pennsylvania State University
* [http://swift.sonoma.edu/ Swift website] by Sonoma State University
* [http://grb.sonoma.edu/ Gamma-ray Burst Real-time Sky Map]

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