Skip to main content
Circulars over Kafka event name backfill. 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"

472 results found.

  1. Fermi GRB 250504A: Global MASTER-Net observations report
  2. GRB 250419A: LCO optical afterglow multi-band observations
  3. IPN triangulation of GRB 250406B (short/hard)
  4. IPN triangulation of GRB 250322B
  5. IPN triangulation of GRB 250308A (short)
  6. IPN triangulation of GRB 250309B
  7. IPN triangulation of GRB 250217C (short)
  8. EP250207a: EP-WXT detection and XRT follow-up observation
  9. IPN triangulation of GRB 250201A
  10. IPN triangulation of GRB 250118B
  11. IPN triangulation of GRB 250119B
  12. Improved IPN triangulation of GRB 250107C
  13. IPN triangulation of GRB 250113A
  14. IPN triangulation of GRB 250107D (short/hard)
  15. GRB 250101A: Swift-XRT refined Analysis
  16. IPN triangulation of GRB 241128B
  17. IPN triangulation of GRB 241117A
  18. IPN triangulation of GRB 241107A (short/hard)
  19. IPN triangulation of GRB 241022A (short/hard)
  20. IPN triangulation of GRB 241021A (long)
  21. IPN triangulation of GRB 240930B / EP 240930a
  22. IPN triangulation of GRB 240926A
  23. GRB 240716A: Swift/BAT-GUANO localization skymap of a long burst
  24. IPN triangulation of GRB 240918B
  25. IPN triangulation of GRB 240913C / EP 240913a
  26. IPN triangulation of GRB 240810A (short)
  27. Improved IPN triangulation of GRB 240802A / EP 240802a
  28. IPN triangulation of GRB 240715A (short)
  29. EP240703a: Kinder optical follow-up observations
  30. IPN triangulation of GRB 240627A
  31. IPN triangulation of GRB 240619C
  32. LIGO/Virgo/KAGRA S240621dy: Identification of a GW compact binary merger candidate
  33. IPN triangulation of GRB 240615A (short)
  34. Konus-Wind detection of GRB 240607A
  35. IPN triangulation of GRB 240607A
  36. IPN triangulation of GRB 240603A
  37. IPN triangulation of the initial episode of GRB 240529A
  38. Konus-Wind detection of GRB 240513A
  39. IPN triangulation of GRB 240504A
  40. IPN triangulation of GRB 240501B and GRB 240501A - possible episodes of ultra long GRB
  41. GRB 240419A: Swift-XRT refined Analysis
  42. IPN triangulation of GRB 240410A
  43. IPN triangulation of GRB 240303B
  44. IPN triangulation of GRB 240125A (short)
  45. IPN triangulation of GRB 240123C (short)
  46. IPN triangulation of GRB 240112A (long)
  47. IPN triangulation of GRB 231129C
  48. IPN triangulation of GRB 231205A
  49. IPN triangulation of GRB 231020A
  50. IPN triangulation of GRB 230919A (short)
  51. IPN triangulation of GRB 230911D (long)
  52. IPN triangulation of GRB 230906A (short)
  53. IPN triangulation of GRB 230815B
  54. IPN triangulation of GRB 230803A
  55. IPN triangulation of GRB 230723A (short)
  56. IPN triangulation of GRB 230715D
  57. IPN triangulation of GRB 230625B (ultra-long)
  58. IPN triangulation of GRB 230616A (short)
  59. GRB 230524A: AstroSat CZTI detection
  60. LIGO/Virgo/KAGRA S230520ae: Identification of a GW compact binary merger candidate: End-to-End Test
  61. IPN triangulation of GRB 230430A (short)
  62. GRB 230420A: Swift/UVOT Upper Limits
  63. IPN triangulation of GRB 230418A (short)
  64. GRB 230328B: AstroSat CZTI detection
  65. IPN triangulation of GRB 230304B
  66. IPN triangulation of GRB 230308A (short/bright)
  67. Further improved IPN localization for GRB 230307A
  68. Fermi GRB 230310A: Global MASTER-Net observations report
  69. Improved IPN localization for GRB 230307A
  70. IPN triangulation of GRB 230307A (long/very bright)
  71. IPN triangulation of GRB 230209B
  72. IPN triangulation of GRB 230116B (short)
  73. IPN triangulation of GRB 221226A
  74. GRB 221216A: Swift-XRT refined Analysis
  75. IPN triangulation of GRB 221209A (long)
  76. LAT GRB221119.63: Global MASTER-Net observations report
  77. IPN triangulation of GRB 221017A (long)
  78. IPN triangulation of GRB 220927A (long)
  79. IceCube Alert 220629.99: Global MASTER-Net observations report
  80. IceCube Alert 220627.74: Global MASTER-Net observations report
  81. IPN triangulation of GRB 220624A
  82. IPN triangulation of GRB 220617A (short)
  83. IPN triangulation of GRB 220613A
  84. IPN triangulation of GRB 220609B
  85. IPN triangulation of GRB 220601A (long)
  86. Konus-Wind detection of GRB 220524B
  87. IPN triangulation of GRB 220525A
  88. IPN triangulation of GRB 220524B
  89. IPN triangulation of GRB 220524A
  90. IPN triangulation of GRB 220522B
  91. IPN triangulation of GRB 220521B
  92. IPN triangulation of GRB 220519A
  93. IPN triangulation of GRB 220426A
  94. IPN triangulation of GRB 220411A
  95. IPN triangulation of short/soft GRB 220406A
  96. IPN triangulation of GRB 220403C
  97. IPN triangulation of GRB 220320A
  98. GRB 220306B: Swift/UVOT Upper Limits
  99. IPN triangulation of GRB 220310A
  100. IPN triangulation of GRB 220305B

Advanced

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