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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"

11049 results found.

  1. AGILE observations of two bright bursts from SGR 1935+2154
  2. Fermi GBM observation of another bright burst in the direction of SGR 1935+2154
  3. Fermi trigger No 653151835: Global MASTER-Net observations report
  4. Fermi trigger No 653124492: Global MASTER-Net observations report
  5. Fermi trigger No 653122278: Global MASTER-Net observations report
  6. GRB 210912B: Fermi GBM Final Real-time Localization
  7. Fermi trigger No 653093506: Global MASTER-Net observations report
  8. Fermi trigger No 653066776: Global MASTER-Net observations report
  9. Fermi trigger No 653084584: Global MASTER-Net observations report
  10. Fermi trigger No 653083551: Global MASTER-Net observations report
  11. Fermi trigger No 653079281: Global MASTER-Net observations report
  12. Fermi trigger No 653066130: Global MASTER-Net observations report
  13. Fermi trigger No 653072474: Global MASTER-Net observations report
  14. Fermi trigger No 653071808: Global MASTER-Net observations report
  15. Fermi trigger No 653054042: Global MASTER-Net observations report
  16. Fermi trigger No 653049776: Global MASTER-Net observations report
  17. Fermi trigger No 653022153: Global MASTER-Net observations report
  18. Fermi trigger No 653031163: Global MASTER-Net observations report
  19. Fermi GBM observation of a bright flare in the direction of SGR 1935+2154
  20. Fermi trigger No 653010039: Global MASTER-Net observations report
  21. IPN triangulation of a bright burst from SGR 1935+2154
  22. Fermi trigger No 652957973: Global MASTER-Net observations report
  23. Fermi trigger No 652944960: Global MASTER-Net observations report
  24. Fermi trigger No 652981861: Global MASTER-Net observations report
  25. Fermi trigger No 652934203: Global MASTER-Net observations report
  26. Fermi trigger No 652927551: Global MASTER-Net observations report
  27. Fermi trigger No 652911693: Global MASTER-Net observations report
  28. Fermi trigger No 652906639: Global MASTER-Net observations report
  29. Fermi GRB 210909A: Global MASTER-Net observations report
  30. GECAM observation of a burst from SGR J1555.2-5402
  31. GRB 210909A: Fermi GBM Final Real-time Localization
  32. GRB 210905A: AstroSat CZTI detection
  33. Konus-Wind detection of GRB 210905A
  34. Fermi GBM Sub-Threshold Detection of GRB 210905A
  35. Fermi GBM trigger 652585475 / 210906073 is not a GRB
  36. Fermi trigger No 652585475: Global MASTER-Net observations report
  37. GRB 210827B: GECAM detection
  38. Fermi GRB 210904A: Global MASTER-Net observations report
  39. GRB 210904A: Fermi GBM Final Real-time Localization
  40. Fermi GRB 210903A: Global MASTER-Net observations report
  41. GRB 210903C: Fermi GBM Final Real-time Localization
  42. Fermi GRB 210903B: Global MASTER-Net observations report
  43. GRB 210903B: Fermi GBM Final Localization
  44. Fermi GBM observation of a burst from SGR J1555.2-5402
  45. GRB 210903A: Fermi GBM Final Real-time Localization
  46. GRB 210822A: CALET Gamma-Ray Burst Monitor detection
  47. GRB 210827A: Swift/UVOT Upper Limits
  48. GRB 210827A: BOOTES-5/JGT optical upper limit
  49. GRB 210827A: Fermi GBM Observation
  50. GRB 210826A: AstroSat CZTI detection
  51. Fermi GRB 210827A: Global MASTER-Net observations report
  52. Fermi GRB 210827B: Global MASTER-Net observations report
  53. GRB 210827A: Swift/BAT-GUANO detection and arcminute localization
  54. GRB 210827B: BALROG localization (Fermi Trigger 651751821 / GRB 210827424)
  55. GRB 210827B: Fermi GBM Final Real-time Localization
  56. GRB 210826A: Swift-XRT observations
  57. GRB 210827A: Fermi GBM Final Real-time Localization
  58. GRB 210822A: CAHA 2.2m observations
  59. GRB 210826A: Fermi-LAT detection
  60. Fermi GRB 210826A: Global MASTER-Net observations report
  61. GRB 210826A: Tiled Swift observations
  62. GRB 210824A: MITSuME Akeno optical upper limits
  63. GRB 210826A: BALROG localization (Fermi Trigger 651654110 / GRB 210826293)
  64. GRB 210826A: Fermi GBM Final Real-time Localization
  65. GRB 210824A: BOOTES-5/JGT optical upper limit
  66. GRB 210824A: Fermi GBM Observation
  67. Fermi GRB 210824A: Global MASTER-Net observations report
  68. GRB 210824A: Fermi GBM Final Real-time Localization
  69. GRB 210822B: DDOTI Upper Limits on the Afterglow
  70. GRB 210822A: Detection by GRBAlpha
  71. Konus-Wind detection of GRB 210822A
  72. GRB 210822A: AstroSat CZTI detection
  73. Fermi trigger No 651306769: Global MASTER-Net observations report
  74. GRB 210822A: Fermi-LAT detection
  75. Fermi GRB 210822B: Global MASTER-Net observations report
  76. GRB 210822B: Fermi GBM Final Real-time Localization
  77. Fermi GRB 210821A: Global MASTER-Net observations report
  78. GRB 210821A: Fermi GBM Final Real-time Localization
  79. GRB 210820B: Fermi GBM Final Localization
  80. Fermi trigger No 651110719: Global MASTER-Net observations report
  81. IceCube-210730A: not observable by Fermi-GBM
  82. IceCube-210811A: Upper limits from Fermi-GBM Observations
  83. GRB 210815A: BALROG localization (Fermi Trigger 650687034 / GRB 210815100)
  84. GRB 210815A: Fermi GBM Final Real-time Localization
  85. Fermi trigger No 650687034: Global MASTER-Net observations report
  86. GRB 210812A is consistent with being a lensed GRB
  87. GRB 210712A: Fermi GBM observation
  88. GRB 210813A: BALROG localization (Fermi Trigger 650508868 / GRB 210813038)
  89. Fermi GRB 210813A: Global MASTER-Net observations report
  90. GRB 210813A: Fermi GBM Final Real-time Localization
  91. Fermi-LAT Gamma-ray Observations of IceCube-210811A
  92. Retraction of Fermi GBM GCN 30630 and GCN 30632
  93. Fermi GRB 210812A: Global MASTER-Net observations report
  94. GRB 210812B: Fermi GBM Final Real-time Localization
  95. GRB 210812A: BALROG localization (Fermi Trigger 650479626 / GRB 210812699)
  96. GRB 210812A: Fermi GBM Final Real-time Localization
  97. GRB 080102A: Fermi GBM Final Real-time Localization
  98. GRB 080101A: Fermi GBM Final Real-time Localization
  99. IceCube-210811A - IceCube observation of a high-energy neutrino candidate track-like event
  100. GRB 210802A: Further Swift/XRT observation and afterglow confirmation

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