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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"
  1. GECAM observations of a series of bursts from SGR J1935+2154
  2. GRB 220101A: continued 1.3m DFOT optical observations of a high-redshift afterglow
  3. Fermi trigger No 663669570: Global MASTER-Net observations report
  4. GRB 220111A: AstroSat CZTI detection
  5. Fermi trigger No 663658976: Global MASTER-Net observations report
  6. Fermi trigger No 663618072: Global MASTER-Net observations report
  7. Fermi GRB 220111A: Global MASTER-Net observations report
  8. Konus-Wind detection of GRB 220101A (correction to GCN 31433)
  9. GRB 220111A: BALROG localization (Fermi Trigger 663621714 / GRB 220111807)
  10. GRB 220111A: Fermi GBM Final Real-time Localization
  11. Konus-Wind detection of GRB 220101A
  12. Fermi Gamma-ray Burst Monitor trigger 220111325/663580106 is not a GRB
  13. GRB 220107A: SAO RAS optical observations
  14. Konus-Wind detection of GRB 220107B
  15. Konus-Wind detection of GRB 220107A
  16. GECAM observations of a series of bursts from SGR J1935+2154
  17. Confirmation of the X-ray afterglow of GRB 220107B
  18. GRB 220107A: further SAO RAS optical observations
  19. GRB 220101A: Additional Liverpool telescope photometry
  20. Fermi trigger No 663406755: Global MASTER-Net observations report
  21. GRB 220107A: 6m BTA spectroscopic redshift
  22. GRB 220107A: SAO RAS optical observations
  23. GRB 220108A: Swift/BAT-GUANO detection outside the coded FOV
  24. GRB 220101A: SAO RAS optical observations
  25. GRB 220107A: AbAO and Terskol optical observations
  26. GRB 220107B: MITSuME Akeno optical upper limits
  27. GRB 220107B: Nanshan/NEXT optical upper limits and host galaxy candidate
  28. GRB 220107A: Nanshan/NEXT optical observations
  29. GRB 220107A: Swift/UVOT Detection
  30. GRB 220107B: Fermi GBM observations
  31. GRB 220107A: MITSuME Akeno optical observation
  32. GRB 220107B: AstroSat CZTI detection
  33. GRB 220107B: Swift-XRT afterglow detection
  34. GRB 220107A: Swift-XRT afterglow detection
  35. GRB 220107B: Fermi-LAT detection
  36. GRB 220107A: AstroSat CZTI detection
  37. GRB 220107B: Tiled Swift observations
  38. GRB 220107A: Fermi GBM observations
  39. Fermi trigger No 663274898: Global MASTER-Net observations report
  40. GRB 220107A: Swift ToO observations
  41. Fermi GRB 220107A: Global MASTER-Net observations report
  42. GRB 220107A: Swift/BAT-GUANO arcminute localization
  43. GRB 220101A: Tautenburg observations
  44. GRB 220107A: BALROG localization (Fermi Trigger 663259536 / GRB 220107615)
  45. GRB 220107A: Fermi GBM Final Real-time Localization
  46. GRB 220101A: Continued Mondy optical observations
  47. GECAM observation of a burst from SGR J1555.2-5402
  48. GECAM detection of a short burst from SGR 1935+2154
  49. GRB 220101A: further TNG NIR observations
  50. GRB 220101A: continued 1.3m DFOT Optical Observations
  51. Fermi trigger No 663129379: Global MASTER-Net observations report
  52. GRB 220104A: Fermi GBM Observation
  53. GECAM observations of a series of bursts from SGR J1935+2154
  54. GRB 220101A: Mondy optical observations
  55. GRB 220101A: 3rd LCO Optical Observation
  56. GRB 220101A: 2.2m CAHA (+CAFOS) first day optical detection
  57. GRB 220101A: iTelescope optical observations
  58. GRB 211227A: Lijiang 2.4m Telescope Optical Observations
  59. GRB 220101A: VLA detection
  60. GRB 220101A: 1.3m DFOT observations
  61. GRB 220101A: LCO Continued Optical Observations
  62. GRB 220104A：GECAM detection
  63. Fermi GRB 220104A: Global MASTER-Net observations report
  64. GRB 220104A: Fermi GBM Final Real-time Localization
  65. GRB 211229B: Fermi GBM observation
  66. Fermi GRB 220103A: Global MASTER-Net observations report
  67. GRB 220103A: Fermi GBM Final Real-time Localization
  68. GRB 211227A: Gemini South Optical Observations
  69. GRB 211229B: Swift/BAT-GUANO detection outside the coded FOV
  70. Alert from the HAWC Burst Monitor HAWC-220103A
  71. GRB 220101A: TNG NIR afterglow detection
  72. GRB 220101A: ALMA detection
  73. GRB 220101A: LCO Optical Observations
  74. GRB 220101A: Tautenburg observations
  75. GRB 220101A: Swift-BAT refined analysis
  76. GRB 220101A: GMG observation (2nd epoch)
  77. GRB 211231A: AstroSat CZTI detection
  78. GRB 220101A: OASDG optical observations
  79. GRB 220101A : Eiso equals the maximum isotropic GRB energy
  80. GRB 220101A: GMG observation
  81. GRB 220101A: Asiago spectroscopic and photometric detection
  82. Fermi trigger No 662768315: Global MASTER-Net observations report
  83. GRB220101A: optical afterglow detection from Konkoly Observatory
  84. GRB 220101A: Fermi GBM Detection
  85. GRB 220101A: NOT redshift confirmation
  86. GRB 220101A: CAHA 2.2m/CAFOS detection
  87. GRB 220101A: Liverpool telescope imaging of a high-redshift afterglow
  88. GRB 220101A: THO optical observations
  89. GRB 220101A: Swift-XRT refined Analysis
  90. GRB 220101A: AGILE detection
  91. GRB 220101A: Xinglong-2.16m photometry and spectroscopy
  92. Swift GRB220101.22: Global MASTER-Net observations report
  93. GRB 220101: Swift/UVOT Detection
  94. GRB 220101A: Fermi-LAT detection
  95. GRB 220101A: Enhanced Swift-XRT position
  96. GRB 220101A: Correction to GCN 31347
  97. GRB 220101A: Swift detection of a burst with a bright optical counterpart
  98. IPN triangulation of GRB 211219A
  99. GRB 211231A: GECAM detection
  100. GRB 211229B: AGILE detection

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