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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"

21113 results found.

  1. GRB 211023A: continued 1.3m DFOT Optical Observations and possible jet break
  2. Fermi trigger No 657742914: Global MASTER-Net observations report
  3. GRB 211023B: Subaru optical observation
  4. Fermi GRB 211102A: Global MASTER-Net observations report
  5. GRB 211024A: 1.3m DFOT observations
  6. Fermi GRB 211031A: Global MASTER-Net observations report
  7. GRB 211023A: 1.3m DFOT Optical Observations
  8. GRB 2121023B: 6 GHz VLA radio upper limit
  9. GRB 211023A: Terskol optical observations
  10. AMON NuEm-211020A: No Candidate Counterparts from Swift-XRT follow up observations
  11. GRB 211023A: continued Mondy optical observations
  12. GRB 211024A: Swift-XRT source 4 is not an afterglow.
  13. GRB 211023B: NUTTelA-TAO / BSTI Early Optical Limits (Preliminary)
  14. Fermi GRB 211027A: Global MASTER-Net observations report
  15. GRB 211024A: Possible afterglow candidate from GIT
  16. GRB 211024A: Swift-XRT observations
  17. GRB 211018A: Swift-XRT observations
  18. GRB 211024A: Swift ToO observations
  19. GRB 211024A: Swift/BAT-GUANO detection and candidate arcminute localization of a short burst
  20. GRB 211023A: Mondy optical observations
  21. GRB 211023B: Gemini-North Optical Observations
  22. Swift GRB 211025A: Global MASTER-Net observations report
  23. GRB 211023B: LDT Optical Afterglow Detection
  24. GRB 211025A: Swift/UVOT Detection
  25. GRB 211023A: 1.5m OSN optical observation
  26. GRB 210610B: Sintesz-Newton/CrAO optical observations
  27. GRB 211024B: Nanshan/NEXT optical afterglow detection
  28. GRB 210919A: FORS2/VLT observations
  29. GRB 211023A: OAJ Bright Afterglow Confirmation
  30. Swift GRB 211024B: Global MASTER-Net observations report
  31. Fermi-LAT Gamma-ray Observations of IceCube-211023A
  32. GRB 211023A: MASTER OT J045237.07+851925.2 - optical counterpart discovery
  33. GRB 211023B: Swift/UVOT Detection
  34. Fermi GRB 211023A: Global MASTER-Net observations report
  35. Swift GRB 211023B: Global MASTER-Net observations report
  36. Fermi GRB 211024A: Global MASTER-Net observations report
  37. IceCube Alert 211023.36: Global MASTER-Net observations report
  38. GRB 211018A: Swift ToO observations
  39. Fermi trigger No 656506979: Global MASTER-Net observations report
  40. AMON Coincidence Alert from the sub-threshold IceCube-HAWC search NuEm-211020A
  41. Fermi trigger No 656268212: Global MASTER-Net observations report
  42. GRB 211019A: Detection by GRBAlpha
  43. GRB 211018A: Detection by GRBAlpha
  44. Fermi GRB 211019A: Global MASTER-Net observations report
  45. Fermi trigger No 656288898: Global MASTER-Net observations report
  46. Swift GRB211017.99: Global MASTER-Net observations report
  47. Integral GRB211016.42: Global MASTER-Net observations report
  48. IceCube-210922A: Hard X-ray flux limit for JCMT/SCUBA2 source from NuSTAR observations
  49. Swift trigger 1078701: MITSuME Akeno optical upper limits
  50. Fermi trigger No 655673024: Global MASTER-Net observations report
  51. GRB 210919A: LDT optical observations and candidate host galaxies
  52. IceCube-20210922A: No optical counterparts found by MITSuME observations
  53. Swift Trigger 1078701: Mondy, CrAO, AbAO observations, possible optical counterpart
  54. Fermi trigger No 655646385: Global MASTER-Net observations report
  55. Swift GRB211010.45: Global MASTER-Net observations report
  56. IceCube-20210922A: DESNU Optical counterpart candidate from 5 nights of DECam observations
  57. Fermi trigger No 655401471: Global MASTER-Net observations report
  58. GRB 210928A: MeerKAT detection
  59. IceCube-210922A: DESI Observations
  60. Fermi trigger No 654854799: Global MASTER-Net observations report
  61. GRB 210928A: Kinder SLT-40cm optical limits
  62. GRB 210928A: Swift-XRT analysis (replaces GCN 30914)
  63. Fermi trigger No 654739449: Global MASTER-Net observations report
  64. Swift GRB211001.03: Global MASTER-Net observations report
  65. GRB 210930A: Swift/UVOT Upper Limits
  66. Swift GRB 210930A: Global MASTER-Net observations report
  67. Fermi trigger No 654658271: Global MASTER-Net observations report
  68. Fermi GRB 210929B: Global MASTER-Net observations report
  69. Fermi-LAT Gamma-ray Observations of IceCubeCascade-210926A
  70. GRB 210919A OSN 1.5m Source Confirmation
  71. GRB 210919A CAHA 2.2m Observations: Afterglow/Host Galaxy Candidate
  72. IceCube-210922A: JCMT/SCUBA2 observations
  73. IceCube-210922A: No Candidate Counterparts from Swift/XRT follow up observations
  74. IceCube-210922A: Upper limits from Fermi-GBM Observations
  75. IceCube-210922A: No Candidate Counterparts from the Zwicky Transient Facility
  76. GECAM observations of a series of bursts from SGR J1935+2154 (2021-09-15T14 to 2021-09-23T14)
  77. Fermi-LAT Gamma-ray Observations of IceCube-210922A
  78. IceCube Alert 210922.76: Global MASTER-Net observations report
  79. GRB 210912A: LBT optical observations
  80. GRB 210919A: Lowell Discovery Telescope upper limits (correction to GCN 30859)
  81. GRB210919A: Keck NIRC2 Kp band upper limits
  82. GRB 210919A: Swift/UVOT Upper Limits
  83. GRB 210919A: LOAO and LSGT optical upper limits
  84. GRB 210919A: NOT upper limits
  85. GRB 210919A: AbAO optical upper limit
  86. Swift GRB 210919A: Global MASTER-Net observations report
  87. Swift trigger 1073821: detection of IGR J16418-4532
  88. GRB 210912A: BOOTES-5/JGT optical afterglow candidate (Correction to GCNC 30823)
  89. GECAM observations of bursts from SGR J1935+2154 (2021-09-13T01 to 2021-09-15T14)
  90. GRB 210909A: Detection by GRBAlpha
  91. GRB 210912A: Tautenburg observations
  92. GECAM observations of bursts from SGR J1935+2154 (2021-09-12T05 to 2021-09-13T01)
  93. AGILE observations of two bright bursts from SGR 1935+2154
  94. GRB 210912A: CAHA 2.2m Detection
  95. GRB 210912A: Swift/UVOT Detection
  96. Fermi GBM observation of another bright burst in the direction of SGR 1935+2154
  97. Fermi trigger No 653151835: Global MASTER-Net observations report
  98. Fermi trigger No 653124492: Global MASTER-Net observations report
  99. Fermi trigger No 653122278: Global MASTER-Net observations report
  100. Swift GRB 210912A: Global MASTER-Net observations report

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