Skip to main content
Updates to LVK & CHIME Notices, Schema v7.2.3! See news and announcements

GCN Circulars

GCN Circulars are rapid astronomical bulletins submitted by and distributed to community members worldwide. They are used to share discoveries, observations, quantitative near-term predictions, requests for follow-up observations, or future observing plans related to high-energy, multi-messenger, and variable or transient astrophysical events. See the documentation for help with subscribing to or submitting Circulars.

Search for Circulars by submitter, subject, or body text (e.g. 'Fermi GRB').
To navigate to a specific circular, enter the associated Circular ID (e.g. 'gcn123', 'Circular 123', or '123').
Advanced Search

To narrow the search results, use advanced search syntax. This allows for specifying which circular field to search (submitter, subject, and/or body). For additional information, refer to the advanced search documentation.

Advanced Search Examples (click to copy):

subject:"Swift"
body:"GRB"
submitter:"Judith Racusin"

7416 results found.

  1. LIGO/Virgo/KAGRA S241125n: DDOTI Optical Upper Limits
  2. LIGO/Virgo/KAGRA S241125n: Gaoyazi/GOT optical observations
  3. LIGO/VIRGO/KAGRA S241125n: GROWTH-India telescope optical observations
  4. LIGO/Virgo/KAGRA S241125n: COLIBRÍ Upper Limits on a Optical Counterpart at the BAT Position
  5. LIGO/Virgo/KAGRA S241125n: Upper limits from Fermi-GBM Observations
  6. LIGO/Virgo/KAGRA S241125n: Updated Coincidence with External Event
  7. LIGO/Virgo/KAGRA S241125n: Kinder optical upper limit in the BAT error region
  8. LIGO/Virgo/KAGRA S241125n: Updated Sky localization
  9. LIGO/Virgo/KAGRA S241125n: Updated Coincidence with External Event
  10. LIGO/Virgo/KAGRA S241125n: No counterpart candidates in INTEGRAL SPI-ACS prompt observation, comparisong with Swift/BAT counterpart
  11. LIGO/Virgo/KAGRA S241109bn: Upper limits from a two-week IceCube neutrino search
  12. LIGO/Virgo/KAGRA S241125n: Updated Sky localization and Coincidence with External Event
  13. LIGO/Virgo/KAGRA S241125n: Swift/BAT-GUANO candidate counterpart
  14. LIGO/Virgo/KAGRA S241125n: Identification of a GW compact binary merger candidate
  15. LIGO/Virgo/KAGRA S241122a: Updated Sky localization and Source Classification
  16. LIGO/Virgo/KAGRA S241122a: Identification of a GW compact binary merger candidate
  17. GRB241120A: OHP/T193 optical observations
  18. GRB 241120A: Mondy and AbAO optical observations
  19. GRB 241112B: Mephisto further optical observations
  20. LIGO/Virgo/KAGRA S241116cq: Upper limits from Swift/BAT-GUANO
  21. LIGO/Virgo/KAGRA S241114y: Updated Sky localization
  22. Updates to IceCube realtime alert system for muon tracks
  23. LIGO/Virgo/KAGRA S241116cq: Updated Sky localization
  24. LIGO/Virgo/KAGRA S241116cq: Identification of a GW compact binary merger candidate
  25. GRB 241113B: Mephisto upper limits
  26. LIGO/Virgo/KAGRA S241114bi: Updated Sky localization and EM Bright Classification
  27. LIGO/Virgo/KAGRA S241113p: Updated Sky localization
  28. EP241113a: No Detection in Fermi-GBM Observations
  29. GRB 241115A: Swift detection of a burst
  30. EP 241113a: LBT possible optical counterpart
  31. GRB 241113B: KAIT Optical Afterglow Candidate
  32. LIGO/Virgo/KAGRA S241114bi: Upper limits from Fermi-GBM Observations
  33. LIGO/Virgo/KAGRA S241114bi: Coverage and upper limits from MAXI/GSC observations
  34. LIGO/Virgo/KAGRA S241114bi: Identification of a GW compact binary merger candidate
  35. LIGO/Virgo/KAGRA S241114y: Identification of a GW compact binary merger candidate
  36. Konus-Wind detection of GRB 241107A (short/hard)
  37. LIGO/Virgo/KAGRA S241113p: Identification of a GW compact binary merger candidate
  38. GRB 241113B: Swift ToO observations
  39. IceCube-241113A - IceCube observation of a high-energy neutrino candidate track-like event
  40. LIGO/Virgo/KAGRA S241111bn: Updated Sky localization
  41. GRB 241112B: LCO optical detection of the SVOM/VT candidate
  42. GRB 241107A: Swift/BAT candidate arcminute localization of a short burst
  43. GRB 241112B: Mephisto optical upper limits
  44. GRB 241112B: Swift ToO observations
  45. LIGO/Virgo/KAGRA S241110br: NED Galaxies in the Localization Volume
  46. LIGO/Virgo/KAGRA S241109bn: ATLAS observations and discovery of the potential counterpart AT2024aawt
  47. LIGO/Virgo/KAGRA S241111bn: Identification of a GW compact binary merger candidate
  48. LIGO/Virgo/KAGRA S241110br: Updated Sky localization
  49. LIGO/Virgo/KAGRA S241110bk: 1 counterpart neutrino candidate event from an IceCube neutrino search
  50. LIGO/Virgo/KAGRA S241110br: Identification of a GW compact binary merger candidate
  51. LIGO/Virgo/KAGRA S241109bn: Coverage and upper limits from MAXI/GSC observations
  52. LIGO/Virgo/KAGRA S241109bn: Updated Sky localization and EM Bright Classification
  53. LIGO/Virgo/KAGRA S241109bn: Upper limits from Fermi-GBM Observations
  54. LIGO/Virgo/KAGRA S241109p: Updated Sky localization and Source Classification
  55. LIGO/Virgo/KAGRA S241109bn: Identification of a GW compact binary merger candidate
  56. LIGO/Virgo/KAGRA S241109p: Identification of a GW compact binary merger candidate
  57. GRB 241108A: Swift ToO observations
  58. EP241107a: Kinder optical follow-up observations
  59. EP241101a: CrAO ZTSH optical observations
  60. LIGO/Virgo/KAGRA S241106ba: 1 counterpart neutrino candidate event from an IceCube neutrino search
  61. LIGO/Virgo/KAGRA S241102o: 1 counterpart neutrino candidate event from an IceCube neutrino search
  62. GRB 241104A: The SVOM/VT candidate in GCN circular 38086 is not an astrophysical source
  63. GRB 241105A: Swift ToO observations
  64. GRB 241104A: Swift ToO observations
  65. GRB 241104A: NOT optical non-detection
  66. GRB 241105A: GOTO tentative optical counterpart candidate
  67. GRB 241104A: SVOM/VT optical candidate
  68. EP241101a: EP-FXT observations update
  69. LIGO/Virgo/KAGRA S241104a: Retraction of GW compact binary merger candidate
  70. LIGO/Virgo/KAGRA S241102cy: Updated Sky localization
  71. LIGO/Virgo/KAGRA S241102br: Updated Sky localization
  72. EP241101a: Optical upper limits with Kinder observations
  73. EP241101a: OHP/T193 optical observations
  74. LIGO/Virgo/KAGRA S241101ee: Updated Sky localization
  75. S241102cy: Identification of a GW compact binary merger candidate
  76. LIGO/Virgo/KAGRA S241102br: NED Galaxies in the Localization Volume
  77. LIGO/Virgo/KAGRA S241102br: Identification of a GW compact binary merger candidate
  78. LIGO/Virgo/KAGRA S241101ee: Identification of a GW compact binary merger candidate
  79. GRB 241030B: Montarrenti Observatory optical upper limit
  80. GRB241030B: GRANDMA/TAROT Upper Limit
  81. GRB 241030B: Swift detection of a burst
  82. GRB 241030A: AKO Optical Afterglow Detection
  83. GRB 241030A: Swift detection of a burst with a bright optical counterpart
  84. GRB 241029A: TRT optical afterglow candidate detection
  85. GRB 241029A: Swift ToO observations
  86. GRB 241026A: Swift detection of a burst
  87. LIGO/Virgo/KAGRA S241009l: Upper limits from Swift/BAT-GUANO
  88. EP 241021A: Swift ToO observations
  89. GRB 241025A: Swift detection of a burst with an optical counterpart
  90. GRB 241001A: ATCA radio observations
  91. EP241021a: No Detection in Fermi-GBM Observation
  92. EP241021a: Optical counterpart observations with the Liverpool Telescope
  93. EP241021a: GSP detects optical candidate counterpart
  94. EP241021a: Optical upper limits with Kinder observations
  95. GRB 241018A/sb24101802: Mephisto optical upper limit
  96. GRB 241018A: REM optical/NIR upper limits
  97. GRB 241018A: NOT optical observations
  98. GRB 241018A: SVOM/VT follow-up and optical candidate
  99. GRB 241018A: LCO/0.4m optical upper limits
  100. GRB 241018A: Swift ToO observations

Advanced

Download all Circulars as a .tar.gz archive (updated once a day):
Looking for U.S. government information and services? Visit USA.gov