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"

3115 results found.

  1. LIGO/Virgo/KAGRA S240422ed: Continued Magellan Observations
  2. LIGO/Virgo/KAGRA S240422ed: Zwicky Transient Facility contuinued observations of S240422ed and candidate analysis
  3. LIGO/Virgo/KAGRA S240422ed: Further near-infrared observations with Subaru/MOIRCS by J-GEM Collaboration
  4. LIGO/Virgo/KAGRA S240422ed: No significant candidates in GRANDMA and Kilonova-Catcher galaxy targeting observations
  5. LIGO/Virgo S240422ed: Swift-XRT detection of 3 possible counterparts
  6. LIGO/Virgo/KAGRA S240422ed: Subaru/MOIRCS near-infrared observations by J-GEM Collaboration
  7. LIGO/Virgo/KAGRA S240422ed: GOTO counterpart search
  8. LIGO/Virgo/KAGRA S240422ed: Zwicky Transient Facility observations and candidates
  9. LIGO/Virgo/KAGRA S240422ed: Magellan Observations
  10. Fermi GRB 240422A: Global MASTER-Net observations report
  11. Fermi GRB 240421B: Global MASTER-Net observations report
  12. Fermi trigger No 735280430: Global MASTER-Net observations report
  13. GRB 240418A: TSHAO Zeiss-1000 optical upper limit
  14. Fermi GRB 240417A: Global MASTER-Net observations report
  15. Improved IPN triangulation of GRB 240411A
  16. EP240416A: MASTER optical observations
  17. Fermi GRB 240415A: Global MASTER-Net observations report
  18. LIGO/Virgo/KAGRA S240413p: Global MASTER-Net observations report
  19. LIGO/Virgo/KAGRA S240413p: Zwicky Transient Facility observations
  20. GRB 240411B: CrAO/ZTSh optical observations
  21. IceCube Alert 240412.23: Global MASTER-Net observations report
  22. Swift Trigger 1220736: detection of 4U 1543-62.
  23. Fermi GRB 240407A: Global MASTER-Net observations report
  24. GRB 240405B: Fermi GBM Final Real-time Localization
  25. GRB 240405A: Fermi GBM Final Real-time Localization
  26. LXT 240402A/GRB 240402B: Glowbug gamma-ray detection
  27. Konus-Wind detection of LXT 240402A/GRB 240402B
  28. LXT 240402A: MASTER optical observations with AGN in error-box
  29. GRB 240402B: GECAM-C detection
  30. X-ray transient LXT 240402A: LEIA detection
  31. EP240331A: MASTER optical observations
  32. Fermi trigger No 733366352: Global MASTER-Net observations report
  33. Fermi GRB 240329A: Global MASTER-Net observations report
  34. GRB 240329A: Fermi GBM Final Real-time Localization
  35. Fermi GRB 240328B: Global MASTER-Net observations report
  36. Fermi GRB 240328A: Global MASTER-Net observations report
  37. IceCube-240327B: No candidates from the Zwicky Transient Facility
  38. GRB 240328A: Fermi GBM Final Real-time Localization
  39. IceCube Alert 240327.68: Global MASTER-Net observations report
  40. Fermi trigger No 733097506: Global MASTER-Net observations report
  41. Fermi trigger No 733092476: Global MASTER-Net observations report
  42. Konus-Wind detection of GRB 240315C (possible counterpart of EP240315a)
  43. GRB 240320A: Fermi GBM Final Real-time Localization
  44. Fermi GRB 240318A: Global MASTER-Net observations report
  45. GRB 240317A: AstroSat CZTI detection
  46. Fermi GRB 240317B: Global MASTER-Net observations report
  47. Fermi trigger No 732299243: Global MASTER-Net observations report
  48. Fermi trigger No 731839490: Global MASTER-Net observations report
  49. Fermi GRB 240310A: Global MASTER-Net observations report
  50. Fermi GRB 240306A: Global MASTER-Net observations report
  51. Fermi GRB 240305A: Global MASTER-Net observations report
  52. GRB 240218A: ALMA detection
  53. IPN triangulation of GRB 240229A
  54. GRB240218A: ATCA observation of the radio counterpart
  55. Swift Trigger 1218645: Another detection of Swift J151857.0-572147
  56. Konus-Wind detection of GRB 240225B (long)
  57. Fermi GRB 240227A: Global MASTER-Net observations report
  58. GRB 240218A: CMO SAI NIR upper limit
  59. Fermi trigger No 730618809: Global MASTER-Net observations report
  60. GRB 240218A: VLA detection
  61. Transient EPW20240219aa: 7DT Optical Upper Limits
  62. GRB 240215B: GRBAlpha detection
  63. Fermi trigger No 729914426: Global MASTER-Net observations report
  64. GRB 240218A: REM detection of a NIR afterglow candidate
  65. Swift GRB240218.08: Global MASTER-Net observations report
  66. Fermi trigger No 729703985: Global MASTER-Net observations report
  67. GRB 240214A/1H 0451-560: MAXI/GSC detection
  68. Fermi GRB 240213A: Global MASTER-Net observations report
  69. GRB 240209A: GOTO optical counterpart candidate
  70. Fermi trigger No 729152364: Global MASTER-Net observations report
  71. Fermi trigger No 729012023: Global MASTER-Net observations report
  72. GRB 240205B: Fermi GBM Observation
  73. Fermi trigger No 728749569: Global MASTER-Net observations report
  74. GRB 240205B: MASTER OT J232550.14-550704.6 counterpart detection
  75. Swift GRB240205.93: Global MASTER-Net observations report
  76. Fermi Gamma-ray Burst Monitor trigger 728740048/240204491 is not a GRB
  77. Fermi trigger No 728796365: Global MASTER-Net observations report
  78. IceCube Alert 240204.38: Global MASTER-Net observations report
  79. GRB 240127A: Fermi GBM Final Real-time Localization
  80. GRB 240123A: GRBAlpha detection
  81. GRB 240118A: Mondy optical observations
  82. GRB 240118A: Swift-XRT afterglow detection
  83. GRB 240118A: AbAO optical upper limit
  84. AMON Coincidence Alert from the sub-threshold IceCube-HAWC search NuEm-240118A
  85. IPN triangulation of GRB 240112A (long)
  86. GRB 240115B: AstroSat CZTI detection
  87. GRB 240107A: VZLUSAT-2 detection
  88. GRB 240115B: Fermi GBM Final Real-time Localization
  89. Fermi trigger No 726774492: Global MASTER-Net observations report
  90. Fermi GRB 240112B: Global MASTER-Net observations report
  91. IceCube-240105A: Three candidates from the Zwicky Transient Facility
  92. GRB 240107A: MAXI/GSC detection
  93. Fermi trigger No 726194053: Global MASTER-Net observations report
  94. GRB 231230A: GOTO optical upper limits
  95. Fermi trigger No 725592555: Global MASTER-Net observations report
  96. LAT GRB231222.31: Global MASTER-Net observations report
  97. GRID detection of GRB 231215A
  98. Fermi trigger No 724781422: Global MASTER-Net observations report
  99. GRB 231215A: GRBAlpha detection
  100. Swift GRB231216.77: Global MASTER-Net observations report

Advanced

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