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"

32698 results found.

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

Advanced

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