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"

36152 results found.

  1. Fermi Gamma-ray Burst Monitor trigger 737133200/240511634 is not a GRB
  2. GRB 240511A: Prompt enhanced Swift-XRT position
  3. GRB 240511A: Swift detection of a burst
  4. GRB 240511A: Fermi GBM Final Real-time Localization
  5. Fermi Gamma-ray Burst Monitor trigger 737076431/240510977 is not a GRB
  6. Fermi Gamma-ray Burst Monitor trigger 230925241/717313591 is not a GRB
  7. EP240506a: CrAO ZTSH optical upper limit
  8. GRB 240504A: Fermi GBM Observation
  9. Fermi Gamma-ray Burst Monitor trigger 736837160/240508208 is not a GRB
  10. IPN triangulation of GRB 240504A
  11. GRB 240502A: 1.3m DFOT Optical upper limit
  12. GRB 240504A: Swift/BAT-GUANO detection of a burst outside the coded FOV
  13. GRB 240502C: Zeiss-1000 at Koshka observatory observations of GOTO optical counterpart candidates
  14. IPN triangulation of GRB 240501B and GRB 240501A - possible episodes of ultra long GRB
  15. Fermi GRB 240504A: Global MASTER-Net observations report
  16. GRB 240503A: AstroSat CZTI detection
  17. GRB 240504A: BALROG localization (Fermi Trigger 736492377 / GRB 240504217)
  18. GRB 240504A: Fermi GBM Final Real-time Localization
  19. LXT 240402A / GRB 240402B: VLT X-shooter redshift of host
  20. GRB 240502A: GOTO optical upper limit
  21. GRB 240502A: Fermi GBM Observation
  22. GRB 240415A 1.3m DFOT Optical upper limit
  23. GRB 240502C: GOTO possible optical counterpart candidates
  24. Fermi GRB 240502B: Global MASTER-Net observations report
  25. GRB 240502C: Fermi GBM Final Localization
  26. Fermi GRB 240502A: Global MASTER-Net observations report
  27. GRB 240501B: GRBAlpha detection
  28. GRB 240430A: GRBAlpha detection
  29. GRB 240502B: Fermi GBM Final Real-time Localization
  30. GRB 240502A long GRB detected by INTEGRAL
  31. GRB 240502A: Fermi GBM Final Real-time Localization
  32. Fermi GRB 240501A: Global MASTER-Net observations report
  33. GRB 240426A: VZLUSAT-2 detection
  34. GRB 240425A: VZLUSAT-2 detection
  35. GRB240430A: Fermi GBM Final Localization
  36. GRB 240501B: AstroSat CZTI detection
  37. GRB 240501A: Fermi GBM Final Real-time Localization
  38. GRB 240408B: VZLUSAT-2 detection
  39. GRB 240407A: VZLUSAT-2 detection
  40. X-ray transient EP240414a: Detection of associated supernova
  41. GRB 240425A: GRBAlpha detection
  42. GRB 240429A: Fermi GBM Final Real-time Localization
  43. Fermi GRB 240428A: Global MASTER-Net observations report
  44. GRB 240428A: Fermi GBM Final Real-time Localization
  45. GRB 240426A: AstroSat CZTI detection
  46. EP240426a: YAHPT optical upper limit
  47. GRB 240414A: NOEMA detection
  48. IceCube-240424A: Upper limits from a search for additional neutrino events in IceCube
  49. LIGO/Virgo/KAGRA S240422ed: Upper limits from GECAM Observations
  50. GRB 240425A: Fermi GBM Final Real-time Localization
  51. GRB 240419B: Swift-BAT refined analysis
  52. GRB 240421B: Swift-BAT refined analysis
  53. GRB 240422A: Glowbug gamma-ray detection
  54. IceCube-240424A - IceCube observation of a high-energy neutrino candidate track-like event
  55. GRB 240421B: GRBAlpha detection
  56. IceCube-240419A: Upper limits from a search for additional neutrino events in IceCube
  57. GRB 240419A: Swift-BAT refined analysis
  58. GRB 240418A: Swift-BAT refined analysis
  59. LXT240402A/GRB240402B: Chandra X-ray detection
  60. GRB 240419A: Possible ATCA radio detection
  61. GRB 240421B: ATCA radio observations
  62. LIGO/Virgo S240422ed: No counterpart candidates in INTEGRAL SPI-ACS prompt observation
  63. LIGO/Virgo/KAGRA S240422ed: AstroSat CZTI non-detection and upper limits
  64. LIGO/Virgo/KAGRA S240422ed: Upper limits from Fermi-GBM Observations
  65. LIGO/Virgo/KAGRA S240421ar: Upper limits from Swift/BAT-GUANO
  66. GRB 240421A: Glowbug gamma-ray detection
  67. GRB 240414A: radio detection with the VLA
  68. GRB 240414A: AMI-LA radio observations
  69. GRB 240414A: LBT optical detection
  70. GRB 240419B : MITSuME Akeno optical upper limits
  71. GRB 240415B: Swift-XRT observations
  72. GRB 240415A: Swift-XRT refined Analysis
  73. Fermi GRB 240422A: Global MASTER-Net observations report
  74. GRB 240421B: AstroSat CZTI detection
  75. GRB 240422A: Fermi GBM Final Real-time Localization
  76. GRB240421B: Zadko Observations
  77. Fermi GRB 240421B: Global MASTER-Net observations report
  78. Swift GRB 240421B: Global MASTER-Net observations report
  79. GRB 240421B: Fermi GBM Observation
  80. GRB 240421B: Swift-XRT refined Analysis
  81. GRB240421B: BOOTES-5/JGT optical upper limit
  82. GRB 240421B: J-band upper limits from WINTER
  83. GRB 240421B: Swift/UVOT Upper Limits
  84. GRB 240421B: Enhanced Swift-XRT position
  85. Fermi GRB 240421A: Global MASTER-Net observations report
  86. GRB 240421B: Swift detection of a burst
  87. EP240420a: Nanshan optical counterpart observations
  88. GRB 240421A: Fermi GBM Final Real-time Localization
  89. GRB240419A: Skynet Optical Afterglow Analysis
  90. GRB240418A - Candidate afterglow from NIRES
  91. GRB 240419B: Swift/UVOT Upper Limits
  92. GRB 240419A: Swift/UVOT Upper Limits
  93. GRB 240419B: Swift-XRT refined Analysis
  94. GRB 240419B: optical afterglow from the NOT
  95. Swift GRB 240419B: Global MASTER-Net observations report
  96. EP240414A: Terskol Zeiss-2000 optical upper limit
  97. GRB 240419B: Enhanced Swift-XRT position
  98. Swift GRB 240419A: Global MASTER-Net observations report
  99. GRB 240418A: Swift/UVOT Upper Limits
  100. GRB 240419A: REM NIR afterglow detection

Advanced

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