Skip to main content
JSON Notices via Email, Kafka Cron Jobs, Submitter Profile, GCN is Hiring. See news and announcements

GCN Circulars

GCN Circulars are rapid bulletins submitted by and distributed to the community. 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"

32688 results found.

  1. GRB 260114A: Fermi GBM observation
  2. GRB 260112B: GECAM-B observation
  3. GRB 260114A: GMG Optical Observation
  4. Fermi-LAT Gamma-ray Observations of IceCube-260111A
  5. EP-WXT trigger 01709251266: SVOM/C-GFT confirmation of a stellar flare
  6. IceCube-260111A: Upper limits from a search for additional neutrino events in IceCube
  7. EP260110a: NOT and GTC Optical and Near-Infrared Observations
  8. EP260110a: TRT optical upper limits
  9. Konus-Wind detection of GRB 260101A
  10. GRB 260111A: Swift-XRT observations
  11. GRB 260111A: COLIBRÍ optical afterglow candidate
  12. GRB 260111A: GECAM-B observation of a burst
  13. GRB 260111A: Fermi GBM Observation
  14. Swift Trigger 1434591 is not a GRB
  15. GRB 260111A: GOTO optical upper limits
  16. GRB 260111A: Swift ToO observations
  17. GRB 251230A: Mondy Optical Observations
  18. GRB 260111A: Swift/BAT-GUANO arcminute localization of a burst
  19. EP260110a: SVOM/VT optical upper limits
  20. EP260110a: Global MASTER-Net observations report
  21. Fermi GRB 260111A: Global MASTER-Net observations report
  22. EP260110a: KAIT optical upper limit
  23. EP260110a: refined analysis of the EP-WXT and EP-FXT observations
  24. EP 260110a: COLIBRÍ optical observations
  25. EP260110a: SVOM/C-GFT upper limit
  26. EP260110a: BOOTES-5/JGU optical upper limit
  27. GRB 260109C: LCO optical upper limits
  28. GRB 260109C: Kilonova-Catcher optical upper limit
  29. EP260105b / GRB 260105C : Fermi-GBM Sub-Threshold Detection
  30. GRB 260104A: Swift-BAT refined analysis
  31. GRB 260101A: Swift-BAT refined analysis
  32. Swift GRB 251230A: Global MASTER-Net OT detection
  33. Fermi GRB 260107A: Global MASTER-Net observations report
  34. GRB 260102A: AbAO optical observations
  35. EP260105b/EP-WXT trigger 01709251028: Einstein Probe detection of an X-ray transient
  36. Fermi GRB 260105A: Global MASTER-Net observations report
  37. EP260105a: FTW optical observations
  38. EP260104a: FTW optical observations
  39. GRB 260105A: SVOM/GRM observation
  40. GRB 260105B: SVOM/GRM observation
  41. FRB 20251229A: COLIBRÍ optical upper limits
  42. Fermi GRB 260105B: Global MASTER-Net observations report
  43. EP260105a: SVOM/VT optical upperlimit
  44. EP260105a: refined analysis of the EP-WXT and EP-FXT observations
  45. EP260105a: LCO Optical Upper limit
  46. EP260104a: Global MASTER-Net observations report
  47. GRB 260101A: COLIBRÍ optical upper limits
  48. EP260105a: Global MASTER-Net observations report
  49. GRB 260103A: Insight-HXMT/HE detection
  50. GRB 260104A: COLIBRÍ optical upper limits
  51. Fermi GRB 260104B: Global MASTER-Net observations report
  52. Swift GRB 260104A: Global MASTER-Net observations report
  53. GRB 251230A/EP-WXT trigger 01709250693: Mephisto optical upper limits
  54. GRB 260101A: Swift/UVOT Detection
  55. GRB 260103A: GECAM-B observation of a burst
  56. Fermi-LAT Gamma-ray Observations of IceCube-251225A
  57. GRB 260101A: COLIBRÍ optical observations
  58. Fermi GBM Sub-Threshold Detection of GRB 260102A
  59. GRB 260102A: EP-FXT follow-up observation
  60. EP260101a: Global MASTER-Net observations report
  61. GRB 260102A: LCO optical upper limits
  62. GRB 260102A: Swift-XRT observations
  63. GRB 260102A: SVOM/COLIBRÍ (FM-GFT) optical observations
  64. GRB 251230A / EP251230a: GECAM-B detection
  65. GRB 260102A: SVOM/VT optical counterpart
  66. GRB 251230A / EP251230a: Insight-HXMT/HE detection
  67. GRB 260102A: Swift ToO observations
  68. GRB 260101A: Fermi GBM Observation
  69. EP260101a: refined analysis of the EP-WXT and EP-FXT observations
  70. GRB 260101A: GECAM-B detection
  71. GRB 260101A: NOT spectroscopic observations
  72. GRB 260101A: SVOM/GRM observation
  73. Swift GRB 260101A: Global MASTER-Net observations report
  74. GRB 260101A: OSIRIS+ redshift z = 2.623 for the new year burst
  75. GRB 260101A: LCO detection of the optical counterpart
  76. GRB 251230A / EP251230a: SVOM/VT optical continued observations and upper limit
  77. GRB 251230A: GRANDMA/TAROT Early Detection
  78. GRB 251230A / EP251230a: further NOT optical observations revealing shallower decay or possible rebrightening
  79. GRB 251230A/EP251230a: Optical upper limit with Kinder observations
  80. EP251229a: Optical upper limit with Kinder observations
  81. GRB 251230A: 1.3m DFOT optical upper limit
  82. GRB 251222A: Mondy Optical Observations
  83. EP251230a / GRB 251230A: refined analysis of the EP-WXT and EP-FXT observations
  84. GRB 251230A: Swift/UVOT detection
  85. GRB251230A: 7DT optical upper limits
  86. GRB 251230A / EP251230a: NOT observations and spectroscopic redshift upper limit z < 2.2
  87. EP251229a: BOOTES-2 early optical upper limit
  88. GRB 251230A: GOTO optical upper limit
  89. EP251229a: NOT optical upper limits
  90. GRB 251230A / EP251230a: SVOM/VT optical observation
  91. EP251229a: refined analysis of the EP-WXT and EP-FXT observations
  92. GRB 251230A: Early optical counterpart detection by LCO.
  93. EP-WXT trigger 01709250662 Mephisto and 50cm telescope follow-up
  94. GRB 251230A: Optical Observations via Virtual Telescope Project, Italy
  95. EP251230a / GRB 251230A: Einstein Probe detection of an X-ray transient
  96. GRB 251230A/EP#01709250693 (likely EP251230a): FTW optical and NIR observations
  97. LIGO/Virgo/KAGRA S251112cm: Candidates from the NSF-DOE Vera C. Rubin Observatory
  98. Swift GRB 251230A: Global MASTER-Net observations report
  99. The EP-WXT trigger 01709250693/GRB 251230A: Las Cumbres detection of the optical counterpart
  100. EP251229a: 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