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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"

26358 results found.

  1. GRB 211024A: Possible afterglow candidate from GIT
  2. GRB 211024A: Swift-XRT observations
  3. GRB 211018A: Swift-XRT observations
  4. GRB 211025A: Optical Afterglow Detection
  5. GRB211023A: optical afterglow detection from Konkoly Observatory
  6. GRB 211024A: Swift/BAT-GUANO detection and candidate arcminute localization of a short burst
  7. GRB 211023B: Mondy optical afterglow confirmation
  8. GRB 211023B: LDT Optical Afterglow Detection
  9. IceCube-211023A: Upper limits from a search for additional neutrino events in IceCube
  10. GRB 211025A: Swift-BAT refined analysis
  11. GRB 211025A: Swift-XRT refined Analysis
  12. GRB 211024B: Swift-XRT refined Analysis
  13. GRB 211025A: Swift/UVOT Detection
  14. GRB 211024B: Swift-BAT refined analysis
  15. GRB 211025A: Enhanced Swift-XRT position
  16. GRB 211025A: Swift detection of a burst
  17. GECAM detection of a short burst probably from SGR J1555.2-5402
  18. GRB 211024B: Nanshan/NEXT optical afterglow detection
  19. GRB 210919A: FORS2/VLT observations
  20. GRB 211023B: Swift-BAT refined analysis
  21. Fermi-LAT Gamma-ray Observations of IceCube-211023A
  22. GRB 211023B: Swift/UVOT Detection
  23. GRB 211024A: GECAM detection
  24. GRB 211023B: RATIR Optical and NIR Upper Limits
  25. GRB 211023B: TSHAO optical observation
  26. IceCube-211023A: No neutrino counterpart detected with ANTARES
  27. GRB 211022A: AstroSat CZTI detection
  28. GRB 211023B: Swift-XRT refined Analysis
  29. GRB 211023B: Enhanced Swift-XRT position
  30. GRB 211023A: Fermi GBM detection
  31. GRB 211023B: Swift detection of a possibly short burst with an optical counterpart
  32. IPN Triangulation of GRB 210927B
  33. GRB 211022A: GECAM detection
  34. AMON IC_HAWC NuEm-211020A: No neutrino counterpart detected with ANTARES
  35. GRB 211021A: BALROG localization (Fermi Trigger 656506979 / GRB 211021460)
  36. Fermi trigger No 656506979: Global MASTER-Net observations report
  37. BepiColombo MGNS joins the IPN
  38. Fermi trigger No 656268212: Global MASTER-Net observations report
  39. GRB 211018A: Fermi GBM observation
  40. GRB 211019A: BALROG localization (Fermi Trigger 656315976 / GRB 211019250)
  41. Integral GRB211016.42: Global MASTER-Net observations report
  42. IceCube-210922A: Hard X-ray flux limit for JCMT/SCUBA2 source from NuSTAR observations
  43. Swift trigger 1078701: MITSuME Akeno optical upper limits
  44. Fermi trigger No 655673024: Global MASTER-Net observations report
  45. GRB 210919A: LDT optical observations and candidate host galaxies
  46. Swift Trigger 1078701: Mondy, CrAO, AbAO observations, possible optical counterpart
  47. Swift Trigger 1078701 is probably not a GRB
  48. IceCube-20210922A: DESNU Optical counterpart candidate from 5 nights of DECam observations
  49. GRB 211008A: BALROG localization (Fermi Trigger 655401471 / GRB 211008665)
  50. GRB 210928A: MeerKAT detection
  51. GECAM observation of a burst from SGR J1555.2-5402
  52. GRB 210928A: Kinder SLT-40cm optical limits
  53. GRB 210930A: Swift-BAT refined analysis
  54. SGR 1935+2154: Swift/BAT-GUANO detection and arcminute localization
  55. GRB 210928A: Swift-XRT analysis (replaces GCN 30914)
  56. GRB 210928A: Swift-XRT refined Analysis
  57. GRB 210928A: Fermi GBM observation
  58. GRB 210927B: GECAM detection
  59. GRB 210927A: GIT optical follow-up of ZTF21acdwctm.
  60. Swift Trigger 1076121 is not a GRB
  61. Swift GRB211001.03: Global MASTER-Net OT detection
  62. GRB 210930A: Swift/UVOT Upper Limits
  63. GRB 210930A: Swift-XRT refined Analysis
  64. Swift GRB 210930A: Global MASTER-Net observations report
  65. GRB 210930A: Enhanced Swift-XRT position
  66. Fermi trigger No 654658271: Global MASTER-Net observations report
  67. GRB 210930A: Swift detection of a burst
  68. Fermi-LAT Gamma-ray Observations of IceCubeCascade-210926A
  69. GRB 210927A: Zwicky Transient Facility Follow-Up of a Fermi Short GRB (Trigger 654396242)
  70. IPN triangulation of GRB 210925B
  71. GRB 210919A: iTelescope T-11 upper limits
  72. IceCube-210926A: No neutrino counterpart candidates in ANTARES search
  73. GRB 210926A: GECAM detection
  74. IceCube-210922A: JCMT/SCUBA2 observations
  75. GRB 210925A: GECAM detection
  76. IceCube-210922A: No significant detection in HAWC
  77. IceCube-210922A: No neutrino counterpart candidates in ANTARES search
  78. GRB 210923B: GECAM detection
  79. GRB 210919A: DECam Upper Limits
  80. Fermi-LAT Gamma-ray Observations of IceCube-210922A
  81. GRB 210919A: Swift-BAT refined analysis
  82. GRB 210912A: LBT optical observations
  83. GRB 210919A: Lowell Discovery Telescope upper limits (correction to GCN 30859)
  84. GRB 210919A: Swift/UVOT Upper Limits
  85. GRB 210919A: LOAO and LSGT optical upper limits
  86. GRB 210919A: MITSuME Akeno optical upper limits
  87. GRB 210919A: NOT upper limits
  88. GRB 210919A: AbAO optical upper limit
  89. GRB 210919A: Enhanced Swift-XRT position
  90. GRB 210919A: LCO Optical Upper Limit
  91. GRB 210919A: Swift detection of a short burst
  92. Swift trigger 1073821: detection of IGR J16418-4532
  93. GRB 210912A: BOOTES-5/JGT optical afterglow candidate (Correction to GCNC 30823)
  94. GRB 210912A: Swift-BAT refined analysis
  95. Konus-Wind observation of the recent SGR 1935+2154 activity
  96. GRB 210912A: Tautenburg observations
  97. GRB 210912A: Swift-XRT refined Analysis
  98. GRB 210912A: Swift/UVOT Detection
  99. Fermi GBM observation of another bright burst in the direction of SGR 1935+2154
  100. GRB 210912A: Enhanced Swift-XRT position

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