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"

7445 results found.

  1. LIGO/Virgo/KAGRA S230814r: Identification of a GW compact binary merger candidate
  2. LIGO/Virgo/KAGRA S230812aj: two counterpart neutrino candidates from IceCube neutrino searches
  3. GRB 230812B: Detected Optical Afterglow Candidate
  4. GRB 230812: Swift/UVOT Detection
  5. GOTO confirmation and possible host galaxy of GRB230812B optical afterglow
  6. GRB 230812B: Zwicky Transient Facility Identifies Optical Afterglow Candidate of a Fermi GRB (Trigger 713559497)
  7. GRB 230812B: KAIT Optical Afterglow Candidate
  8. GRB 230812B: Tiled Swift observations
  9. ZTF23aaoohpy/AT2023lcr: JWST spectroscopy confirmation of an associated type Ic-BL supernova
  10. LIGO/Virgo/KAGRA S230811n: Updated Sky localization
  11. LIGO/Virgo/KAGRA S230811n: Identification of a GW compact binary merger candidate
  12. LIGO/Virgo/KAGRA S230810af: Retraction of GW compact binary merger candidate
  13. GRB 230805B: Iota Scorpii Observatory, La Spezia, Italy upper limit
  14. LIGO/Virgo/KAGRA S230808i: retraction of a GW unmodeled transient candidate
  15. LIGO/Virgo/KAGRA S230808i: Identification of a GW unmodeled transient candidate
  16. LIGO/Virgo/KAGRA S230807f: Updated Sky localization and EM Bright Classification
  17. LIGO/Virgo/KAGRA S230807f: Identification of a GW compact binary merger candidate
  18. LIGO/Virgo/KAGRA S230805x: Upper limits from Swift/BAT-GUANO
  19. LIGO/Virgo/KAGRA S230806ak: Updated Sky localization and EM Bright Classification
  20. LIGO/Virgo/KAGRA S230806ak: Identification of a GW compact binary merger candidate
  21. LIGO/Virgo/KAGRA S230805x: Updated Sky localization
  22. GRB 230805B: Swift detection of a burst
  23. LIGO/Virgo/KAGRA S230805x: Identification of a GW compact binary merger candidate
  24. LIGO/Virgo/KAGRA S230802aq: Updated Sky localization and EM Bright Classification
  25. LIGO/Virgo/KAGRA S230802aq: AstroSat CZTI non-detection and upper limits
  26. LIGO/Virgo/KAGRA S230802aq: Upper limits from Fermi-GBM Observations
  27. LIGO/Virgo S230802aq: No counterpart candidates in INTEGRAL SPI-ACS prompt observation
  28. LIGO/Virgo/KAGRA S230802aq: Coverage and upper limits from MAXI/GSC observations
  29. LIGO/Virgo/KAGRA S230802aq: Identification of a GW compact binary merger candidate
  30. GRB 230802A: Swift detection of a burst
  31. LIGO/Virgo/KAGRA S230731an: Upper limits from Swift/BAT-GUANO
  32. LIGO/Virgo/KAGRA S230731an: AstroSat CZTI non-detection and upper limits
  33. LIGO/Virgo/KAGRA S230731an: Updated Sky Localization and EM Bright Classification, and Correction to Source Classification
  34. LIGO/Virgo/KAGRA S230731an: Coverage and upper limits from MAXI/GSC observations
  35. LIGO/Virgo/KAGRA S230731an: Identification of a GW compact binary merger candidate
  36. LIGO/Virgo/KAGRA S230729z: Updated Sky localization
  37. GRB 230723A: Detection of candidate millimeter-band radiation by SPT-3G
  38. GRB 230723B: MITSuME Ishigaki optical observation
  39. IceCube-230727A: No candidates from the Zwicky Transient Facility
  40. LIGO/Virgo/KAGRA S230729z: Identification of a GW compact binary merger candidate
  41. IceCube-230724A: No counterparts from the Zwicky Transient Facility
  42. GRB 230728A: Swift detection of a burst
  43. IceCube-230727A - IceCube observation of a high-energy neutrino candidate track-like event
  44. LIGO/Virgo/KAGRA S230726a: Updated Sky localization
  45. GRB 230723B: MITSuME Akeno optical afterglow candidate detection
  46. LIGO/Virgo/KAGRA S230726b: one counterpart neutrino candidate from IceCube neutrino searches
  47. IceCube-230724A - IceCube observation of a high-energy neutrino candidate track-like event
  48. LIGO/Virgo/KAGRA S230726a: Identification of a GW compact binary merger candidate
  49. IceCube-230725A - IceCube observation of a high-energy neutrino candidate track-like event
  50. GRB 230723B: GAD Observatory, La Spezia, Italy upper limit
  51. GRB 230723B: Optical afterglow candidate from CAHA
  52. LIGO/Virgo/KAGRA S230723ac: Updated Sky localization
  53. LIGO/Virgo/KAGRA S230723ac: Identification of a GW compact binary merger candidate
  54. LIGO/Virgo/KAGRA S230708z: Updated Sky localization
  55. LIGO/Virgo/KAGRA S230715bw: Retraction of GW compact binary merger candidate
  56. IceCube-230707A : MAXI upper limit and NICER follow-up observation of Swift J1753.5-0127
  57. LIGO/Virgo/KAGRA S230709bi: Updated Sky localization
  58. LIGO/Virgo/KAGRA S230708t: Updated Sky localization
  59. IceCube-230708A: Upper limits from Swift/BAT-GUANO
  60. LIGO/Virgo/KAGRA S230712a: Retraction of GW compact binary merger candidate
  61. LIGO/Virgo/KAGRA S230708z: Identification of a GW compact binary merger candidate
  62. LIGO/Virgo/KAGRA S230708t: Identification of a GW compact binary merger candidate
  63. LIGO/Virgo/KAGRA S230708cf: Updated Sky localization
  64. LIGO/Virgo/KAGRA S230707ai: Updated Sky localization
  65. IceCube-230707A: No candidates from the Zwicky Transient Facility
  66. LIGO/Virgo/KAGRA S230630am: Updated Sky localization
  67. LIGO/Virgo/KAGRA S230630am: Updated Sky localization
  68. LIGO/Virgo/KAGRA S230709bi: Identification of a GW compact binary merger candidate
  69. LIGO/Virgo/KAGRA S230708cf: Identification of a GW compact binary merger candidate
  70. LIGO/Virgo/KAGRA S230708bi: Retraction of GW compact binary merger candidate
  71. IceCube-230708A - IceCube observation of a high-energy neutrino candidate track-like event
  72. IceCube-230707B - IceCube observation of a high-energy neutrino candidate track-like event
  73. IceCube-230707A - IceCube observation of a high-energy neutrino candidate track-like event
  74. LIGO/Virgo/KAGRA S230707ai: Identification of a GW compact binary merger candidate
  75. GRB 230707A: Swift ToO observations
  76. LIGO/Virgo/KAGRA S230706ah: Updated Sky localization
  77. LIGO/Virgo/KAGRA S230704f: Updated Sky localization
  78. LIGO/Virgo/KAGRA S230630bq: Updated Sky localization
  79. LIGO/Virgo/KAGRA S230702an: Updated Sky localization
  80. LIGO/Virgo/KAGRA S230529ay: Updated Sky localization and EM Bright Classification
  81. LIGO/Virgo/KAGRA S230706ah: Identification of a GW compact binary merger candidate
  82. LVK S230619bd/GBM-230619: Upper limits from a two-week IceCube neutrino search
  83. LIGO/Virgo/KAGRA S230704f: Identification of a GW compact binary merger candidate
  84. LIGO/Virgo/KAGRA S230702an: Identification of a GW compact binary merger candidate
  85. LIGO/Virgo/KAGRA low-significance gravitational wave candidate S230701z: one counterpart neutrino candidate from IceCube neutrino searches
  86. LIGO/Virgo/KAGRA S230627c: Upper limits from Swift/BAT-GUANO
  87. LIGO/Virgo/KAGRA S230630bq: Identification of a GW compact binary merger candidate
  88. LIGO/Virgo/KAGRA S230630am: Identification of a GW compact binary merger candidate
  89. GRB 230628E - VLT spectroscopic observations
  90. GRB230628E: VLT optical identification of afterglow candidate
  91. LIGO/Virgo/KAGRA S230628ax: Identification of a GW compact binary merger candidate
  92. GRB 230628E: Swift detection of a burst
  93. LIGO/Virgo/KAGRA low-significance gravitational wave candidate S230628aj: one counterpart neutrino candidate from IceCube neutrino searches
  94. LIGO/Virgo/KAGRA S230516az: GOTO candidate counterpart GOTO23hu ruled out by Zwicky Transient Facility observations
  95. LIGO/Virgo/KAGRA S230527c: No counterpart candidates in INTEGRAL SPI-ACS prompt observation
  96. LIGO/Virgo/KAGRA S230627c: ATLAS information on the ZTF candidates
  97. LIGO/Virgo/KAGRA S230627c: Upper limits from Fermi-GBM Observations
  98. LIGO/Virgo/Kagra S230627c: NED Galaxies in the Localization Volume
  99. LIGO/Virgo/KAGRA S230627c: Coverage and upper limits from MAXI/GSC observations
  100. LIGO/Virgo/KAGRA S230627c: Updated Sky localization and EM Bright Classification

Advanced

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