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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"

11511 results found.

  1. GRB 220101A: Continued Mondy optical observations
  2. GECAM observation of a burst from SGR J1555.2-5402
  3. Fermi trigger No 663129379: Global MASTER-Net observations report
  4. GRB 220104A: Fermi GBM Observation
  5. GRB 220101A: Mondy optical observations
  6. GRB 220101A: 2.2m CAHA (+CAFOS) first day optical detection
  7. GRB 220104A：GECAM detection
  8. Fermi GRB 220104A: Global MASTER-Net observations report
  9. GRB 220104A: Fermi GBM Final Real-time Localization
  10. GRB 211229B: Fermi GBM observation
  11. Fermi GRB 220103A: Global MASTER-Net observations report
  12. GRB 220103A: Fermi GBM Final Real-time Localization
  13. GRB 211229B: Swift/BAT-GUANO detection outside the coded FOV
  14. GRB 211231A: AstroSat CZTI detection
  15. GRB 220101A : Eiso equals the maximum isotropic GRB energy
  16. Fermi trigger No 662768315: Global MASTER-Net observations report
  17. GRB 220101A: Fermi GBM Detection
  18. GRB 220101A: CAHA 2.2m/CAFOS detection
  19. GRB 220101A: AGILE detection
  20. GRB 220101A: Xinglong-2.16m photometry and spectroscopy
  21. GRB 220101A: Fermi-LAT detection
  22. IPN triangulation of GRB 211219A
  23. GRB 211231A: GECAM detection
  24. GRB 211229B: AGILE detection
  25. GRB 211231A: Fermi GBM Final Real-time Localization
  26. GRB 211229A: Swift-XRT and UVOT observations
  27. GRB 211229A: Fermi GBM observation
  28. GRB 211229B: GECAM detection
  29. Fermi GRB 211229B: Global MASTER-Net observations report
  30. GRB 211229B: Fermi GBM Final Real-time Localization
  31. GRB 211229A: Swift/BAT-GUANO arcminute localization
  32. GRB 211229A: GECAM detection
  33. Fermi GRB 211229A: Global MASTER-Net observations report
  34. GRB 211229A: Fermi GBM Final Real-time Localization
  35. Fermi trigger No 662216114: Global MASTER-Net observations report
  36. Fermi GRB 211225C: Global MASTER-Net observations report
  37. GRB 211225C: Fermi GBM Final Real-time Localization
  38. Fermi trigger No 662084433: Global MASTER-Net observations report
  39. GRB 211224A: Fermi GBM Final Real-time Localization
  40. GRB 211211A: observations with the 3.6m Devasthal Optical Telescope
  41. Fermi trigger No 662010159: Global MASTER-Net observations report
  42. AGILE observations of a bright burst from SGR 1935+2154
  43. Fermi GRB 211223B: Global MASTER-Net observations report
  44. Fermi GBM Sub-Threshold Detection of GRB 211221A
  45. Fermi GBM Sub-Threshold Detection of GRB 211207A
  46. GRB 211223B: Fermi GBM Final Real-time Localization
  47. GRB 211223A: GECAM detection
  48. GRB 211219B: AstroSat CZTI detection
  49. GRB 211219A: AstroSat CZTI detection
  50. Fermi GRB 211222A: Global MASTER-Net observations report
  51. GRB 211222A: Fermi GBM Final Real-time Localization
  52. GRB 211219A: AGILE detection
  53. GRB 211219A: Swift/BAT-GUANO detection outside the coded FOV
  54. Fermi GRB 211219B: Global MASTER-Net observations report
  55. GRB 211219B: Fermi GBM Final Real-time Localization
  56. Fermi GRB 211219A: Global MASTER-Net observations report
  57. GRB 211219A: Fermi GBM Final Real-time Localization
  58. GRB 211216A: Fermi GBM observation
  59. Fermi-LAT Gamma-ray Observations of IceCube-211216B
  60. Fermi-LAT Gamma-ray Observations of IceCube-211216A
  61. IceCube-211216B: Upper limits from Fermi-GBM Observations
  62. IceCube-211216A: Upper limits from Fermi-GBM Observations
  63. Fermi trigger No 661417475: Global MASTER-Net observations report
  64. GRB 211216A: Swift/BAT-GUANO detection outside the coded FOV
  65. IceCube-211216B - IceCube observation of a high-energy neutrino candidate track-like event
  66. Fermi GRB 211216B: Global MASTER-Net observations report
  67. GRB 211216B: GECAM detection
  68. GRB 211216B: Fermi GBM Final Real-time Localization
  69. IceCube-211216A - IceCube observation of a high-energy neutrino candidate track-like event
  70. GRB 211216A: GECAM detection
  71. GRB 211216A: BALROG localization (Fermi Trigger 661329957 / GRB 211216282)
  72. Fermi GRB 211216A: Global MASTER-Net observations report
  73. GRB 211216A: Fermi GBM Final Real-time Localization
  74. GRB 211211A: Insight-HXMT/HE detection
  75. GRB 211211A: SAO RAS optical observations
  76. GRB 211211A: AbAO optical observations
  77. GRB 211211A: redshift estimation and SPI-ACS/INTEGRAL detection
  78. GRB 211211A: Very fast decay observed from CAFOS/2.2mCAHA
  79. GRB 211211A: Further observations from CAFOS/2.2m CAHA
  80. GRB 211211A: HCT and GIT optical follow up observations
  81. GRB 211211A: CALET Gamma-Ray Burst Monitor detection
  82. Fermi GRB 211212A: Global MASTER-Net observations report
  83. GRB 211211A: incorrect E_iso value in GCN 31221
  84. GRB 211211A: NOT optical spectroscopy
  85. GRB 211211B: GECAM detection
  86. Fermi GRB 211212B: Global MASTER-Net observations report
  87. GRB 211211A: Afterglow detection from CAFOS/2.2m CAHA
  88. GRB 211211A: MITSuME Akeno optical observation
  89. GRB 211212B: Fermi GBM Final Real-time Localization
  90. GRB 211211A: Nanshan/NEXT optical observations
  91. GRB 211212A: Fermi GBM Final Real-time Localization
  92. GRB 211211A: Fermi GBM observation
  93. Fermi GRB 211211B: Global MASTER-Net observations report
  94. GRB 211211B: Fermi GBM Final Real-time Localization
  95. Fermi GRB 211211A: Global MASTER-Net observations report
  96. GRB 211211A: Fermi GBM Final Real-time Localization
  97. Fermi trigger No 660868196: Global MASTER-Net observations report
  98. Fermi trigger No 660736561: Global MASTER-Net observations report
  99. GRB 211130A: MeerLICHT identification of possible afterglow candidate
  100. Fermi-LAT Gamma-ray Observations of IceCube-211208A

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