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"
  1. Correction to GCN 30915: GRB 210928A: Swift-XRT analysis
  2. GRB 210928A: Kinder SLT-40cm optical limits
  3. GRB 210930A: Swift-BAT refined analysis
  4. SGR 1935+2154: Swift/BAT-GUANO detection and arcminute localization
  5. GRB 210928A: Swift-XRT analysis (replaces GCN 30914)
  6. GRB 210928A: Swift-XRT refined Analysis
  7. GRB 210928A: Fermi GBM observation
  8. GRB 210928A: Fermi-LAT detection
  9. Swift GRB211001.03 / trigger 1076121 : MASTER OT retraction
  10. GRB 210927B: GECAM detection
  11. GRB 210930A: CAHA 2.2m telescope optical limit
  12. GRB 210927A: GIT optical follow-up of ZTF21acdwctm.
  13. Fermi trigger No 654739449: Global MASTER-Net observations report
  14. Swift GRB211001.03: Global MASTER-Net observations report
  15. Swift Trigger 1076121 is not a GRB
  16. Swift GRB211001.03: Global MASTER-Net OT detection
  17. GRB 210930A: Swift/UVOT Upper Limits
  18. GRB 210930A: Swift-XRT refined Analysis
  19. Swift GRB 210930A: Global MASTER-Net observations report
  20. GRB 210930A: Enhanced Swift-XRT position
  21. Fermi trigger No 654658271: Global MASTER-Net observations report
  22. Fermi GRB 210929B: Global MASTER-Net observations report
  23. GRB 210930A: Swift detection of a burst
  24. GRB 210929B: Fermi GBM Final Real-time Localization
  25. Fermi-LAT Gamma-ray Observations of IceCubeCascade-210926A
  26. GRB 210929A: Fermi GBM Final Real-time Localization
  27. GRB 210927A: Zwicky Transient Facility Follow-Up of a Fermi Short GRB (Trigger 654396242)
  28. GRB 210925B: AstroSat CZTI detection
  29. IceCube-210922A: SMA observation for the JCMT candidate
  30. IPN triangulation of GRB 210925B
  31. GRB 210926A: AstroSat CZTI detection
  32. GRB 210919A: iTelescope T-11 upper limits
  33. IceCube-210926A: No neutrino counterpart candidates in ANTARES search
  34. GRB 210926A: GECAM detection
  35. GRB 210927A: Fermi GBM Final Real-time Localization
  36. GRB 210919A OSN 1.5m Source Confirmation
  37. GRB 210919A CAHA 2.2m Observations: Afterglow/Host Galaxy Candidate
  38. IceCube-210922A: JCMT/SCUBA2 observations
  39. GRB 210925A: GECAM detection
  40. GRB 210925A: Fermi GBM Final Real-time Localization
  41. GRB 210919A: Chandra rapid ToO upper limit
  42. GRB 210924A: Fermi GBM Final Real-time Localization
  43. IceCube-210922A: No Candidate Counterparts from Swift/XRT follow up observations
  44. IceCube-210922A: No significant detection in HAWC
  45. IceCube-210922A: No neutrino counterpart candidates in ANTARES search
  46. GRB 210923B: GECAM detection
  47. Retraction of Fermi GBM GRB 210923A: the trigger is not a GRB
  48. IceCube-210922A: Upper limits from a search for additional neutrino events in IceCube
  49. IceCube-210922A: Upper limits from Fermi-GBM Observations
  50. IceCube-210922A: No Candidate Counterparts from the Zwicky Transient Facility
  51. GECAM observations of a series of bursts from SGR J1935+2154 (2021-09-15T14 to 2021-09-23T14)
  52. GRB 210919A: DECam Upper Limits
  53. Fermi-LAT Gamma-ray Observations of IceCube-210922A
  54. Konus-Wind detection of a burst from SGR 1935+2154 on 2021 September 22
  55. GRB 210923A: Fermi GBM Final Real-time Localization
  56. IceCube Alert 210922.76: Global MASTER-Net observations report
  57. GRB 210919A: Swift-BAT refined analysis
  58. IceCube-210922A - IceCube observation of a high-energy neutrino candidate track-like event
  59. GRB 210912A: LBT optical observations
  60. GRB 210919A: Lowell Discovery Telescope upper limits (correction to GCN 30859)
  61. GRB 210919a: Lowell Discovery Telescope upper limits
  62. GRB210919A: Keck NIRC2 Kp band upper limits
  63. GRB 210919A: Swift/UVOT Upper Limits
  64. GRB 210919A: LOAO and LSGT optical upper limits
  65. GRB 210919A: MITSuME Akeno optical upper limits
  66. GRB 210919A: Swift-XRT refined Analysis
  67. GRB 210919B: Fermi GBM Final Real-time Localization
  68. GRB 210919A: NOT upper limits
  69. GRB 210919A: AbAO optical upper limit
  70. GRB 210919A: Enhanced Swift-XRT position
  71. GRB 210919A: LCO Optical Upper Limit
  72. GRB 210919A: BOOTES-2/TELMA optical upper limit
  73. Swift GRB 210919A: Global MASTER-Net observations report
  74. GRB 210919A: Swift detection of a short burst
  75. Swift trigger 1073821: detection of IGR J16418-4532
  76. GRB 210912A: BOOTES-5/JGT optical afterglow candidate (Correction to GCNC 30823)
  77. GRB 210917A: Fermi GBM Final Real-time Localization
  78. GRB 210812A is not a compelling example of a lensed GRB
  79. GECAM observations of bursts from SGR J1935+2154 (2021-09-13T01 to 2021-09-15T14)
  80. GRB 210909A: Detection by GRBAlpha
  81. GRB 210912A: Swift-BAT refined analysis
  82. Konus-Wind observation of the recent SGR 1935+2154 activity
  83. GRB 210912A: Tautenburg observations
  84. GECAM observations of bursts from SGR J1935+2154 (2021-09-12T05 to 2021-09-13T01)
  85. AGILE observations of two bright bursts from SGR 1935+2154
  86. GRB 210912A: CAHA 2.2m Detection
  87. GRB 210912A: Swift-XRT refined Analysis
  88. GRB 210912A: Swift/UVOT Detection
  89. Fermi GBM observation of another bright burst in the direction of SGR 1935+2154
  90. GRB 210912A: Enhanced Swift-XRT position
  91. GRB 210912A: Host-galaxy candidate in PanSTARRS
  92. Fermi trigger No 653151835: Global MASTER-Net observations report
  93. Fermi trigger No 653124492: Global MASTER-Net observations report
  94. Fermi trigger No 653122278: Global MASTER-Net observations report
  95. GRB 210912A: Mondy optical afterglow confirmation
  96. Swift GRB 210912A: Global MASTER-Net observations report
  97. GRB 210912A: BOOTES-5/JGT optical afterglow candidate
  98. GECAM observations of bursts from SGR J1935+2154 (2021-09-11T07 to 2021-09-12T08)
  99. GRB 210912B: Fermi GBM Final Real-time Localization
  100. GRB 210912A: Swift detection of a burst

Advanced

Download all Circulars as a .tar.gz archive (updated once a day):
Questions or comments?
Contact GCN directly.
Have you found a bug in GCN?
Open an issue.
Want to contribute code to GCN?
Get involved on GitHub.

gcn.nasa.gov

A service of the Astrophysics Science Division at NASA Goddard Space Flight Center

Looking for U.S. government information and services? Visit USA.gov