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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"

26054 results found.

  1. GRB 220101A: Mondy optical observations
  2. GRB 220101A: 3rd LCO Optical Observation
  3. GRB 220101A: 2.2m CAHA (+CAFOS) first day optical detection
  4. GRB 220101A: iTelescope optical observations
  5. GRB 211227A: Lijiang 2.4m Telescope Optical Observations
  6. GRB 220101A: 1.3m DFOT observations
  7. GRB 220101A: LCO Continued Optical Observations
  8. GRB 211229B: Fermi GBM observation
  9. GRB 211227A: Gemini South Optical Observations
  10. GRB 211229B: Swift/BAT-GUANO detection outside the coded FOV
  11. GRB 220101A: TNG NIR afterglow detection
  12. GRB 220101A: LCO Optical Observations
  13. GRB 220101A: Swift-BAT refined analysis
  14. GRB 220101A: GMG observation (2nd epoch)
  15. GRB 220101A: OASDG optical observations
  16. GRB 220101A : Eiso equals the maximum isotropic GRB energy
  17. GRB 220101A: GMG observation
  18. GRB 220101A: Asiago spectroscopic and photometric detection
  19. GRB220101A: optical afterglow detection from Konkoly Observatory
  20. GRB 220101A: Fermi GBM Detection
  21. GRB 220101A: NOT redshift confirmation
  22. GRB 220101A: CAHA 2.2m/CAFOS detection
  23. GRB 220101A: Liverpool telescope imaging of a high-redshift afterglow
  24. GRB 220101A: THO optical observations
  25. GRB 220101A: Swift-XRT refined Analysis
  26. GRB 220101A: AGILE detection
  27. GRB 220101A: Xinglong-2.16m photometry and spectroscopy
  28. Swift GRB220101.22: Global MASTER-Net observations report
  29. GRB 220101: Swift/UVOT Detection
  30. GRB 220101A: Fermi-LAT detection
  31. GRB 220101A: Enhanced Swift-XRT position
  32. GRB 220101A: Swift detection of a burst with a bright optical counterpart
  33. IPN triangulation of GRB 211219A
  34. GRB 211229A: Swift-XRT and UVOT observations
  35. GRB 211227A: Deep early CAHA 2.2m/CAFOS observation
  36. GRB 211229A: Fermi GBM observation
  37. GRB 211229C: Swift/BAT-GUANO detection likely outside the coded FOV
  38. GRB 211229A: Swift ToO observations
  39. GRB 211229A: Swift/BAT-GUANO arcminute localization
  40. GRB 211227A: CALET Gamma-Ray Burst Monitor detection
  41. GRB 211225B: CALET Gamma-Ray Burst Monitor detection
  42. GRB 211227A: Swift/UVOT Upper Limits
  43. GRB 211227A: Swift-XRT refined Analysis
  44. GRB 211227A: Swift-BAT refined analysis
  45. Konus-Wind detection of the intermediate flare from SGR 1935+2154
  46. GRB 211227A: A possible short GRB with extended emission at z = 0.228?
  47. GRB 211227A: Liverpool Telescope upper limits
  48. GRB 211227A: Enhanced Swift-XRT position
  49. GRB 211227A: LCO Optical Observations
  50. GRB 211227A: Nanshan/NEXT optical observations and host galaxy candidate
  51. GRB 211227A: MAXI/GSC detection
  52. GRB 211227A: BOOTES-2/TELMA optical upper limit
  53. GRB 211221A: Swift/UVOT Upper Limits
  54. GRB 211227A: Swift detection of a burst
  55. Swift GRB211227.98: Global MASTER-Net observations report
  56. GRB 211226A: Swift/BAT-GUANO detection outside the coded FOV
  57. GRB 211225B: Swift-BAT refined analysis
  58. Swift GRB 211225B: Global MASTER-Net observations report
  59. GRB 211225B: Swift detection of a burst
  60. GRB 211211A: observations with the 3.6m Devasthal Optical Telescope
  61. GRB 211223C: Swift-BAT refined analysis
  62. GRB 211223C: BOOTES-4/MET optical upper limit
  63. Swift GRB 211223C: Global MASTER-Net observations report
  64. Fermi GBM Sub-Threshold Detection of GRB 211221A
  65. Fermi GBM Sub-Threshold Detection of GRB 211207A
  66. GRB 211221A: Swift-BAT refined analysis
  67. GRB 211223C: Swift detection of a burst
  68. GRB 211221A: NUTTelA-TAO / BSTI Early Optical Limits (Preliminary)
  69. GRB 211219A: AstroSat CZTI detection
  70. GRB 211221A: Swift-XRT refined Analysis
  71. GRB 211221A: BOOTES-4/MET optical upper limit
  72. GRB 211221A: MeerLICHT optical limits
  73. GRB 211221A: NOT optical limits
  74. GRB 211221A: Enhanced Swift-XRT position
  75. Swift GRB 211221A: Global MASTER-Net observations report
  76. GRB 211221A: Swift detection of a burst
  77. GRB 211219A: Swift/BAT-GUANO detection outside the coded FOV
  78. GRB 211211A: MMT/MMIRS Observations Indicate Fading of K-band Source
  79. GRB 211216A: Fermi GBM observation
  80. GRB 211106A: XMM-Newton monitoring campaign detections
  81. GRB 211216A: Swift/BAT-GUANO detection outside the coded FOV
  82. GRB 211211A: Insight-HXMT/HE detection
  83. GRB 211211A - Gemini K-band detection
  84. GRB 211211A: SAO RAS optical observations
  85. GRB 211211A: AbAO optical observations
  86. GRB 211211A: GMG upper limit
  87. GRB 211211A: Very fast decay observed from CAFOS/2.2mCAHA
  88. GRB 211211A: Further observations from CAFOS/2.2m CAHA
  89. GRB 211211A: HCT and GIT optical follow up observations
  90. GRB 211211A: CALET Gamma-Ray Burst Monitor detection
  91. GRB 211211A: Swift/UVOT detection
  92. GRB 211211A: NOT optical spectroscopy
  93. GRB 211211A: Afterglow detection from CAFOS/2.2m CAHA
  94. GRB 211211A: MITSuME Akeno optical observation
  95. Swift GRB 211211A: Global MASTER-Net observations report
  96. GRB 211211A: LCO Optical Observations
  97. GRB 211211A: Nanshan/NEXT optical observations
  98. GRB 211211A: Swift-XRT refined Analysis
  99. GRB 211211A: Fermi GBM observation
  100. GRB 211211A: Swift-BAT refined analysis

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