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"

35957 results found.

  1. Konus-Wind detection of GRB 260114A
  2. GRB 260114A: Swift-XRT refined Analysis
  3. GRB 260114A: 6 GHz VLA observations
  4. GRB 260114A: VLT/X-shooter redshift of the putative host galaxy
  5. GRB 260114A : MITSuME Akeno optical upper limits
  6. GRB 260114A: COLIBRÍ optical upper limits
  7. GRB 260114A: TNG NIR upper limit
  8. GRB 260114A: NOT optical observations
  9. Konus-Wind detection of GRB 251230A / EP251230a
  10. GRB 260114A: SVOM/GRM observation of a short burst
  11. Swift GRB 260114A: Global MASTER-Net observations report
  12. GRB 260114A: GECAM-B observation of a short burst
  13. GRB 260114A: Mondy optical observations
  14. GRB 260114A: Fermi GBM observation
  15. GRB 260112B: GECAM-B observation
  16. GRB 260114A: GMG Optical Observation
  17. GRB 260114A: Swift detection of a short burst
  18. GRB 260114A: Fermi GBM Final Real-time Localization
  19. Konus-Wind detection of GRB 260101A
  20. GRB 260111A: Swift-XRT observations
  21. Swift Trigger 1439093: is probably not GRB 260113A
  22. GRB 260111A: COLIBRÍ optical afterglow candidate
  23. GRB 260111A: GECAM-B observation of a burst
  24. GRB 260111A: Fermi GBM Observation
  25. Swift Trigger 1434591 is not a GRB
  26. GRB 260111A: GOTO optical upper limits
  27. GRB 260112B: Fermi GBM Final Real-time Localization
  28. GRB 260111A: Swift ToO observations
  29. GRB 251230A: Mondy Optical Observations
  30. GRB 260111A: Swift/BAT-GUANO arcminute localization of a burst
  31. GRB 260112A: Fermi GBM Final Real-time Localization
  32. Fermi GRB 260111A: Global MASTER-Net observations report
  33. GRB 260111A: Fermi GBM Final Real-time Localization
  34. EP260110a: KAIT optical upper limit
  35. GRB 260109C: LCO optical upper limits
  36. GRB 260109C: Kilonova-Catcher optical upper limit
  37. EP260105b / GRB 260105C : Fermi-GBM Sub-Threshold Detection
  38. Swift Trigger 1434591: possible GRB 260109C
  39. GRB 260109B: Fermi GBM Final Real-time Localization
  40. GRB 260102A: Swift-XRT afterglow detection
  41. GRB 260109A: Fermi GBM Final Real-time Localization
  42. GRB 260104A: Swift-BAT refined analysis
  43. GRB 260101A: Swift-BAT refined analysis
  44. Swift GRB 251230A: Global MASTER-Net OT detection
  45. Fermi GRB 260107A: Global MASTER-Net observations report
  46. GRB 260102A: AbAO optical observations
  47. GRB 260107A: Fermi GBM Final Real-time Localization
  48. Fermi GRB 260105A: Global MASTER-Net observations report
  49. GRB 260105B: Fermi GBM Detection
  50. GRB 260105B: BALROG localization (Fermi Trigger 789348101 / GRB 260105973)
  51. GRB 260105A: SVOM/GRM observation
  52. GRB 260105B: SVOM/GRM observation
  53. Fermi GRB 260105B: Global MASTER-Net observations report
  54. GRB 260105B: Fermi GBM Final Real-time Localization
  55. GRB 260105A: Fermi GBM Final Real-time Localization
  56. GRB 260101A: COLIBRÍ optical upper limits
  57. GRB 260103A: Insight-HXMT/HE detection
  58. GRB 260104A: COLIBRÍ optical upper limits
  59. GRB 260104C: Fermi GBM Final Real-time Localization
  60. Fermi GRB 260104B: Global MASTER-Net observations report
  61. Swift GRB 260104A: Global MASTER-Net observations report
  62. GRB 251230A/EP-WXT trigger 01709250693: Mephisto optical upper limits
  63. GRB 260104A: Swift-XRT refined Analysis
  64. GRB 260104A: Enhanced Swift-XRT position
  65. GRB 260101A: Swift/UVOT Detection
  66. GRB 260103A: GECAM-B observation of a burst
  67. GRB 260104B: Fermi GBM Final Localization
  68. GRB 260104A: Swift detection of a burst
  69. GRB 260103A: SVOM/GRM observation of a possible GRB
  70. GRB 260101A: COLIBRÍ optical observations
  71. GRB 260102B: Fermi GBM Final Real-time Localization
  72. Fermi GBM Sub-Threshold Detection of GRB 260102A
  73. GRB 260102A: EP-FXT follow-up observation
  74. GRB 260102A: LCO optical upper limits
  75. GRB 260102A: Swift-XRT observations
  76. GRB 260102A: SVOM/COLIBRÍ (FM-GFT) optical observations
  77. Fermi Gamma-ray Burst Monitor trigger 789047602/260102495 is not a GRB
  78. GRB 251230A / EP251230a: GECAM-B detection
  79. GRB 260102A: SVOM/VT optical counterpart
  80. GRB 251230A / EP251230a: Insight-HXMT/HE detection
  81. GRB 260102A: Swift ToO observations
  82. GRB 260101A: Fermi GBM Observation
  83. GRB 260102A: SVOM detection of a burst
  84. GRB 260101A: GECAM-B detection
  85. GRB 260101A: NOT spectroscopic observations
  86. GRB 260101A: SVOM/GRM observation
  87. GRB 260101A: Swift-XRT refined Analysis
  88. Swift GRB 260101A: Global MASTER-Net observations report
  89. GRB 260101A: Enhanced Swift-XRT position
  90. GRB 260101A: OSIRIS+ redshift z = 2.623 for the new year burst
  91. GRB 260101A: LCO detection of the optical counterpart
  92. GRB 260101A: Swift detection of a burst with an optical counterpart
  93. GRB 260101A: Fermi GBM Final Real-time Localization
  94. GRB 251230A / EP251230a: SVOM/VT optical continued observations and upper limit
  95. GRB 251230A: GRANDMA/TAROT Early Detection
  96. GRB 251230A / EP251230a: further NOT optical observations revealing shallower decay or possible rebrightening
  97. GRB 251230A/EP251230a: Optical upper limit with Kinder observations
  98. GRB 251230A: 1.3m DFOT optical upper limit
  99. Fermi Gamma-ray Burst Monitor trigger 788833547/251231018 is not a GRB
  100. GRB 251230A: Swift-XRT refined Analysis

Advanced

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