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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. GECAM observation of a burst from SGR J1555.2-5402
  2. Konus-Wind detection of GRB 210928A
  3. Fermi trigger No 654854799: Global MASTER-Net observations report
  4. Correction to GCN 30915: GRB 210928A: Swift-XRT analysis
  5. GRB 210928A: Kinder SLT-40cm optical limits
  6. GRB 210930A: Swift-BAT refined analysis
  7. SGR 1935+2154: Swift/BAT-GUANO detection and arcminute localization
  8. GRB 210928A: Swift-XRT analysis (replaces GCN 30914)
  9. GRB 210928A: Swift-XRT refined Analysis
  10. GRB 210928A: Fermi GBM observation
  11. GRB 210928A: Fermi-LAT detection
  12. Swift GRB211001.03 / trigger 1076121 : MASTER OT retraction
  13. GRB 210927B: GECAM detection
  14. GRB 210930A: CAHA 2.2m telescope optical limit
  15. GRB 210927A: GIT optical follow-up of ZTF21acdwctm.
  16. Fermi trigger No 654739449: Global MASTER-Net observations report
  17. Swift GRB211001.03: Global MASTER-Net observations report
  18. Swift Trigger 1076121 is not a GRB
  19. Swift GRB211001.03: Global MASTER-Net OT detection
  20. GRB 210930A: Swift/UVOT Upper Limits
  21. GRB 210930A: Swift-XRT refined Analysis
  22. Swift GRB 210930A: Global MASTER-Net observations report
  23. GRB 210930A: Enhanced Swift-XRT position
  24. Fermi trigger No 654658271: Global MASTER-Net observations report
  25. Fermi GRB 210929B: Global MASTER-Net observations report
  26. GRB 210930A: Swift detection of a burst
  27. GRB 210929B: Fermi GBM Final Real-time Localization
  28. Fermi-LAT Gamma-ray Observations of IceCubeCascade-210926A
  29. GRB 210929A: Fermi GBM Final Real-time Localization
  30. GRB 210927A: Zwicky Transient Facility Follow-Up of a Fermi Short GRB (Trigger 654396242)
  31. GRB 210925B: AstroSat CZTI detection
  32. IceCube-210922A: SMA observation for the JCMT candidate
  33. IPN triangulation of GRB 210925B
  34. GRB 210926A: AstroSat CZTI detection
  35. GRB 210919A: iTelescope T-11 upper limits
  36. IceCube-210926A: No neutrino counterpart candidates in ANTARES search
  37. GRB 210926A: GECAM detection
  38. GRB 210927A: Fermi GBM Final Real-time Localization
  39. GRB 210919A OSN 1.5m Source Confirmation
  40. GRB 210919A CAHA 2.2m Observations: Afterglow/Host Galaxy Candidate
  41. IceCube-210922A: JCMT/SCUBA2 observations
  42. GRB 210925A: GECAM detection
  43. GRB 210925A: Fermi GBM Final Real-time Localization
  44. GRB 210919A: Chandra rapid ToO upper limit
  45. GRB 210924A: Fermi GBM Final Real-time Localization
  46. IceCube-210922A: No Candidate Counterparts from Swift/XRT follow up observations
  47. IceCube-210922A: No significant detection in HAWC
  48. IceCube-210922A: No neutrino counterpart candidates in ANTARES search
  49. GRB 210923B: GECAM detection
  50. Retraction of Fermi GBM GRB 210923A: the trigger is not a GRB
  51. IceCube-210922A: Upper limits from a search for additional neutrino events in IceCube
  52. IceCube-210922A: Upper limits from Fermi-GBM Observations
  53. IceCube-210922A: No Candidate Counterparts from the Zwicky Transient Facility
  54. GECAM observations of a series of bursts from SGR J1935+2154 (2021-09-15T14 to 2021-09-23T14)
  55. GRB 210919A: DECam Upper Limits
  56. Fermi-LAT Gamma-ray Observations of IceCube-210922A
  57. Konus-Wind detection of a burst from SGR 1935+2154 on 2021 September 22
  58. GRB 210923A: Fermi GBM Final Real-time Localization
  59. IceCube Alert 210922.76: Global MASTER-Net observations report
  60. GRB 210919A: Swift-BAT refined analysis
  61. IceCube-210922A - IceCube observation of a high-energy neutrino candidate track-like event
  62. GRB 210912A: LBT optical observations
  63. GRB 210919A: Lowell Discovery Telescope upper limits (correction to GCN 30859)
  64. GRB 210919a: Lowell Discovery Telescope upper limits
  65. GRB210919A: Keck NIRC2 Kp band upper limits
  66. GRB 210919A: Swift/UVOT Upper Limits
  67. GRB 210919A: LOAO and LSGT optical upper limits
  68. GRB 210919A: MITSuME Akeno optical upper limits
  69. GRB 210919A: Swift-XRT refined Analysis
  70. GRB 210919B: Fermi GBM Final Real-time Localization
  71. GRB 210919A: NOT upper limits
  72. GRB 210919A: AbAO optical upper limit
  73. GRB 210919A: Enhanced Swift-XRT position
  74. GRB 210919A: LCO Optical Upper Limit
  75. GRB 210919A: BOOTES-2/TELMA optical upper limit
  76. Swift GRB 210919A: Global MASTER-Net observations report
  77. GRB 210919A: Swift detection of a short burst
  78. Swift trigger 1073821: detection of IGR J16418-4532
  79. GRB 210912A: BOOTES-5/JGT optical afterglow candidate (Correction to GCNC 30823)
  80. GRB 210917A: Fermi GBM Final Real-time Localization
  81. GRB 210812A is not a compelling example of a lensed GRB
  82. GECAM observations of bursts from SGR J1935+2154 (2021-09-13T01 to 2021-09-15T14)
  83. GRB 210909A: Detection by GRBAlpha
  84. GRB 210912A: Swift-BAT refined analysis
  85. Konus-Wind observation of the recent SGR 1935+2154 activity
  86. GRB 210912A: Tautenburg observations
  87. GECAM observations of bursts from SGR J1935+2154 (2021-09-12T05 to 2021-09-13T01)
  88. AGILE observations of two bright bursts from SGR 1935+2154
  89. GRB 210912A: CAHA 2.2m Detection
  90. GRB 210912A: Swift-XRT refined Analysis
  91. GRB 210912A: Swift/UVOT Detection
  92. Fermi GBM observation of another bright burst in the direction of SGR 1935+2154
  93. GRB 210912A: Enhanced Swift-XRT position
  94. GRB 210912A: Host-galaxy candidate in PanSTARRS
  95. Fermi trigger No 653151835: Global MASTER-Net observations report
  96. Fermi trigger No 653124492: Global MASTER-Net observations report
  97. Fermi trigger No 653122278: Global MASTER-Net observations report
  98. GRB 210912A: Mondy optical afterglow confirmation
  99. Swift GRB 210912A: Global MASTER-Net observations report
  100. GRB 210912A: BOOTES-5/JGT optical afterglow candidate

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