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"

28054 results found.

  1. GRB 231110A: Swift-BAT refined analysis
  2. GRB 231106A: Glowbug gamma-ray detection
  3. GRB 231111A: Xinglong-2.16m optical observations
  4. LIGO/Virgo/KAGRA S231113bb: Identification of a GW compact binary merger candidate
  5. GRB 231104A: VZLUSAT-2 detection
  6. GRB 231110A: Glowbug gamma-ray detection
  7. GRB 231111A: Leavitt Observatory optical observations
  8. GRB231111A: Optical follow-up observations with Mephisto
  9. GRB 231111A: GMG observation (correction)
  10. GRB 231111A: GMG observation upper limit
  11. GRB 231106B: GRBAlpha detection
  12. GRB 231110A: Terskol Zeiss-2000 optical upper limit
  13. GRB 231111A: Swift-XRT refined Analysis
  14. GRB 231111A: Mondy optical observations
  15. GRB 231111A: Enhanced Swift-XRT position
  16. GRB 231110A: SAO RAS optical observations
  17. GRB231111A: GIT confirmation of the optical afterglow
  18. GRB 231111A: Nanshan/HMT optical observations
  19. GRB 231111A: Swift detection of a burst with an optical counterpart
  20. Swift GRB231111.60: Global MASTER-Net observations report
  21. GRB231110A: WFST Observation and upper limits
  22. GRB 231110A: Swift detection of a burst
  23. LIGO/Virgo/KAGRA S231110g: Updated Sky localization
  24. LIGO/Virgo/KAGRA S231110g: Identification of a GW compact binary merger candidate
  25. LIGO/Virgo/KAGRA S231108u: Updated Sky localization
  26. LIGO/Virgo/KAGRA O4 Landscape
  27. LIGO/Virgo/KAGRA S231108u: Identification of a GW compact binary merger candidate
  28. GRB 231104A: Swift-BAT refined analysis
  29. LIGO/Virgo/KAGRA S231102w: Upper limits from Swift/BAT-GUANO
  30. GRB 231104A: NuSTAR Observation of the prompt emission
  31. GRB 231104A: 3.6m DOT optical upper limit
  32. IceCube-231103A: Upper limits from a search for additional neutrino events in IceCube
  33. LIGO/Virgo/KAGRA S231106y: one counterpart neutrino candidate from IceCube neutrino searches
  34. Fermi-LAT gamma-ray observations of IceCube-231103A
  35. GRB 231104A: NOT upper limit
  36. GRB 231104A: Fermi GBM Observation
  37. Fermi GRB 231103A: Global MASTER-Net observations report
  38. LIGO/Virgo/KAGRA S231104ac: Updated Sky localization
  39. GRB 231104A: AKO Upper Limit
  40. GRB 231104A: AstroSat CZTI detection
  41. GRB 231104A: Swift-XRT refined Analysis
  42. GRB 231104A: Fermi-LAT detection
  43. LIGO/Virgo/KAGRA S231104ac: Identification of a GW compact binary merger candidate
  44. GRB 231104A: Swift/UVOT Upper Limits
  45. GRB 231104A: Enhanced Swift-XRT position
  46. GRB231104A: LCOGT Optical Upper Limits
  47. GRB 231104A: Swift detection of a bright burst
  48. Fermi-LAT gamma-ray observations of IceCube-231027A
  49. LIGO/Virgo/KAGRA S231102w: Updated Sky localization
  50. GRB 231101A: Glowbug gamma-ray detection
  51. LIGO/Virgo/KAGRA S231102w: Identification of a GW compact binary merger candidate
  52. New Swift-BAT/GUANO and IceCube Notices Available via GCN Kafka
  53. GRB 231101A: Fermi GBM Final Real-time Localization
  54. GRB 231028B: VZLUSAT-2 detection
  55. GRB 231030B: Fermi GBM Detection
  56. IPN triangulation of GRB 231020A
  57. GRB 231030B: BALROG localization (Fermi Trigger 720388704 / GRB 231030832)
  58. GRB 231028A: Swift-BAT refined analysis
  59. IceCube-231027A: Upper limits from a search for additional neutrino events in IceCube
  60. LIGO/Virgo/KAGRA S231029y: Upper limits from Swift/BAT-GUANO
  61. GRB 231024A: AKO Optical Counterpart Candidate
  62. LIGO/Virgo/KAGRA S231029y: One counterpart neutrino candidate from IceCube neutrino searches
  63. LIGO/Virgo/KAGRA S231029ai: Global MASTER-Net observations report
  64. LIGO/Virgo/KAGRA S231029y: Identification of a GW compact binary merger candidate
  65. GRB 231028A: AstroSat CZTI detection
  66. GRB 231028A: Glowbug gamma-ray detection
  67. GRB 231028A: Fermi GBM Detection
  68. LIGO/Virgo/KAGRA S231028bg: Updated Sky localization
  69. LIGO/Virgo/KAGRA S231028bg: Identification of a GW compact binary merger candidate
  70. GRB 231028A: Swift detection of a burst
  71. GRB 231019A: Glowbug gamma-ray detection
  72. GRB 231025A: Fermi GBM Observation
  73. GRB 231024A: Fermi GBM Observation
  74. GRB 231025A: Swift/BAT-GUANO detection of a likely short burst
  75. GRB 231020B: AstroSat CZTI detection
  76. GRB 231024A: GOTO optical counterpart candidate
  77. LIGO/Virgo/KAGRA S231025a: two counterpart neutrino candidates from IceCube neutrino searches
  78. The photometry of the transient in Messier 31 field: GMG observation
  79. GRB 231018A: Swift/BAT-GUANO detection of a long burst outside the coded FOV
  80. LIGO/Virgo/KAGRA S231020bw: Upper limits from Swift/BAT-GUANO
  81. LIGO/Virgo/KAGRA S231021az: Coverage and upper limits from MAXI/GSC observations
  82. LIGO/Virgo/KAGRA S231020bw: Updated Sky localization
  83. GRB 231020A: Fermi GBM Detection
  84. GRB 231017A: Mondy optical observations. A possible candidate for an afterglow or host galaxy.
  85. GRB 231019A: VZLUSAT-2 detection
  86. GRB 231018A: VZLUSAT-2 detection
  87. GRB 231020B: BALROG localization (Fermi Trigger 719530557 / GRB 231020900)
  88. LIGO/Virgo/KAGRA S231020ba: Updated Sky localization and EM Bright Classification
  89. GRB 231020A: BALROG localization (Fermi Trigger / GRB 231020790)
  90. LIGO/Virgo/KAGRA S231020ba: Upper limits from Fermi-GBM Observations
  91. GRB 231015A: NuSTAR Detection of Prompt Emission
  92. LIGO/Virgo/KAGRA S231020bw: Identification of a GW compact binary merger candidate
  93. LIGO/Virgo/KAGRA S231020ba: Coverage and upper limits from MAXI/GSC observations
  94. GRB 231017A: 1.3m DFOT Optical upper limit
  95. LIGO/Virgo/KAGRA S231020ba: Identification of a GW compact binary merger candidate
  96. IceCube-231004A: Upper limits from Fermi-GBM Observations
  97. GRB 231018A: Glowbug gamma-ray detection
  98. IPN triangulation of GRB 231018A
  99. GRB 231017A: Swift/UVOT Upper Limit
  100. GRB 230911C: ATCA detection of possible radio counterpart

Advanced

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