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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"

27394 results found.

  1. Fermi trigger No 663899819: Global MASTER-Net observations report
  2. Fermi trigger No 663886592: Global MASTER-Net observations report
  3. GRB 220111A: AstroSat CZTI detection
  4. GRB 220111A: BALROG localization (Fermi Trigger 663621714 / GRB 220111807)
  5. GRB 220107A: SAO RAS optical observations
  6. GRB 220107A: further SAO RAS optical observations
  7. GRB 220101A: Additional Liverpool telescope photometry
  8. GRB 220107A: SAO RAS optical observations
  9. GRB 220108A: Swift/BAT-GUANO detection outside the coded FOV
  10. GRB 220107A: AbAO and Terskol optical observations
  11. GRB 220107B: MITSuME Akeno optical upper limits
  12. GRB 220107B: Nanshan/NEXT optical upper limits and host galaxy candidate
  13. GRB 220107A: Nanshan/NEXT optical observations
  14. GRB 220107A: Swift/UVOT Detection
  15. GRB 220107B: Fermi GBM observations
  16. GRB 220107A: MITSuME Akeno optical observation
  17. GRB 220107B: AstroSat CZTI detection
  18. GRB 220107B: Swift-XRT afterglow detection
  19. GRB 220107A: Swift-XRT afterglow detection
  20. GRB 220107A: AstroSat CZTI detection
  21. GRB 220107A: Fermi GBM observations
  22. Fermi trigger No 663274898: Global MASTER-Net observations report
  23. GRB 220107A: Swift/BAT-GUANO arcminute localization
  24. GRB 220101A: Tautenburg observations
  25. GRB 220107A: BALROG localization (Fermi Trigger 663259536 / GRB 220107615)
  26. GECAM observation of a burst from SGR J1555.2-5402
  27. GECAM detection of a short burst from SGR 1935+2154
  28. GRB 220101A: further TNG NIR observations
  29. GRB 220101A: 3rd LCO Optical Observation
  30. GRB 220101A: 2.2m CAHA (+CAFOS) first day optical detection
  31. GRB 220101A: iTelescope optical observations
  32. GRB 211227A: Lijiang 2.4m Telescope Optical Observations
  33. GRB 220101A: LCO Continued Optical Observations
  34. GRB 220104A：GECAM detection
  35. GRB 211229B: Fermi GBM observation
  36. GRB 211227A: Gemini South Optical Observations
  37. GRB 211229B: Swift/BAT-GUANO detection outside the coded FOV
  38. Alert from the HAWC Burst Monitor HAWC-220103A
  39. GRB 220101A: TNG NIR afterglow detection
  40. GRB 220101A: LCO Optical Observations
  41. GRB 220101A: Tautenburg observations
  42. GRB 220101A: Swift-BAT refined analysis
  43. GRB 220101A: GMG observation (2nd epoch)
  44. GRB 211231A: AstroSat CZTI detection
  45. GRB 220101A: OASDG optical observations
  46. GRB 220101A: GMG observation
  47. GRB220101A: optical afterglow detection from Konkoly Observatory
  48. GRB 220101A: Fermi GBM Detection
  49. GRB 220101A: Liverpool telescope imaging of a high-redshift afterglow
  50. GRB 220101A: Swift-XRT refined Analysis
  51. GRB 220101A: Xinglong-2.16m photometry and spectroscopy
  52. GRB 220101: Swift/UVOT Detection
  53. GRB 220101A: Enhanced Swift-XRT position
  54. GRB 220101A: Swift detection of a burst with a bright optical counterpart
  55. IPN triangulation of GRB 211219A
  56. GRB 211231A: GECAM detection
  57. GRB 211229A: Swift-XRT and UVOT observations
  58. GRB 211229A: Fermi GBM observation
  59. GRB 211229C: Swift/BAT-GUANO detection likely outside the coded FOV
  60. GRB 211229A: Swift/BAT-GUANO arcminute localization
  61. GRB 211229A: GECAM detection
  62. GRB 211227A: Swift/UVOT Upper Limits
  63. GRB 211227A: Swift-XRT refined Analysis
  64. GRB 211227A: Swift-BAT refined analysis
  65. Konus-Wind detection of the intermediate flare from SGR 1935+2154
  66. GRB 211227A: Liverpool Telescope upper limits
  67. GRB 211227A: Enhanced Swift-XRT position
  68. GRB 211227A: LCO Optical Observations
  69. GRB 211227A: Nanshan/NEXT optical observations and host galaxy candidate
  70. GRB 211227A: MAXI/GSC detection
  71. GRB 211221A: Swift/UVOT Upper Limits
  72. GRB 211227A: Swift detection of a burst
  73. GRB 211226A: Swift/BAT-GUANO detection outside the coded FOV
  74. GRB 211225B: Swift-BAT refined analysis
  75. GRB 211225A: MITSuME Akeno optical upper limits
  76. MAXI GRB211225.14: Global MASTER-Net observations report
  77. GRB 211225A/MAXI J0827-071: MAXI/GSC detection
  78. GRB 211106A: Third HST Observation
  79. Fermi trigger No 662010159: Global MASTER-Net observations report
  80. GRB 211223C: Swift-BAT refined analysis
  81. Fermi GBM Sub-Threshold Detection of GRB 211221A
  82. Fermi GBM Sub-Threshold Detection of GRB 211207A
  83. GRB 211221A: Swift-BAT refined analysis
  84. GRB 211223C: Swift detection of a burst
  85. GRB 211223A: GECAM detection
  86. GRB 211221A: NUTTelA-TAO / BSTI Early Optical Limits (Preliminary)
  87. GRB 211219B: AstroSat CZTI detection
  88. GRB 211219A: AstroSat CZTI detection
  89. GRB 211221A: Swift-XRT refined Analysis
  90. GRB 211218A: MITSuME Akeno optical upper limits
  91. GRB 211221A: MeerLICHT optical limits
  92. GRB 211221A: NOT optical limits
  93. GRB 211221A: Enhanced Swift-XRT position
  94. GRB 211221A: Swift detection of a burst
  95. IceCube-211216B: No significant detection in HAWC
  96. IceCube-211216A: No significant detection in HAWC
  97. GRB 211219A: Swift/BAT-GUANO detection outside the coded FOV
  98. GRB 211216A: Fermi GBM observation
  99. IceCube-211216B: No neutrino counterpart candidates in ANTARES search
  100. GRB 211218A, MAXI J0909-041: MAXI/GSC detection

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