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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"

11112 results found.

  1. Fermi GRB 210904A: Global MASTER-Net observations report
  2. GRB 210904A: Fermi GBM Final Real-time Localization
  3. Fermi GRB 210903A: Global MASTER-Net observations report
  4. GRB 210903C: Fermi GBM Final Real-time Localization
  5. Fermi GRB 210903B: Global MASTER-Net observations report
  6. GRB 210903B: Fermi GBM Final Localization
  7. Fermi GBM observation of a burst from SGR J1555.2-5402
  8. GRB 210903A: Fermi GBM Final Real-time Localization
  9. GRB 210822A: CALET Gamma-Ray Burst Monitor detection
  10. GRB 210827A: Swift/UVOT Upper Limits
  11. GRB 210827A: BOOTES-5/JGT optical upper limit
  12. GRB 210827A: Fermi GBM Observation
  13. GRB 210826A: AstroSat CZTI detection
  14. Fermi GRB 210827A: Global MASTER-Net observations report
  15. Fermi GRB 210827B: Global MASTER-Net observations report
  16. GRB 210827A: Swift/BAT-GUANO detection and arcminute localization
  17. GRB 210827B: BALROG localization (Fermi Trigger 651751821 / GRB 210827424)
  18. GRB 210827B: Fermi GBM Final Real-time Localization
  19. GRB 210826A: Swift-XRT observations
  20. GRB 210827A: Fermi GBM Final Real-time Localization
  21. GRB 210822A: CAHA 2.2m observations
  22. GRB 210826A: Fermi-LAT detection
  23. Fermi GRB 210826A: Global MASTER-Net observations report
  24. GRB 210826A: Tiled Swift observations
  25. GRB 210824A: MITSuME Akeno optical upper limits
  26. GRB 210826A: BALROG localization (Fermi Trigger 651654110 / GRB 210826293)
  27. GRB 210826A: Fermi GBM Final Real-time Localization
  28. GRB 210824A: BOOTES-5/JGT optical upper limit
  29. GRB 210824A: Fermi GBM Observation
  30. Fermi GRB 210824A: Global MASTER-Net observations report
  31. GRB 210824A: Fermi GBM Final Real-time Localization
  32. GRB 210822B: DDOTI Upper Limits on the Afterglow
  33. GRB 210822A: Detection by GRBAlpha
  34. Konus-Wind detection of GRB 210822A
  35. GRB 210822A: AstroSat CZTI detection
  36. Fermi trigger No 651306769: Global MASTER-Net observations report
  37. GRB 210822A: Fermi-LAT detection
  38. Fermi GRB 210822B: Global MASTER-Net observations report
  39. GRB 210822B: Fermi GBM Final Real-time Localization
  40. Fermi GRB 210821A: Global MASTER-Net observations report
  41. GRB 210821A: Fermi GBM Final Real-time Localization
  42. GRB 210820B: Fermi GBM Final Localization
  43. Fermi trigger No 651110719: Global MASTER-Net observations report
  44. IceCube-210730A: not observable by Fermi-GBM
  45. IceCube-210811A: Upper limits from Fermi-GBM Observations
  46. GRB 210815A: BALROG localization (Fermi Trigger 650687034 / GRB 210815100)
  47. GRB 210815A: Fermi GBM Final Real-time Localization
  48. Fermi trigger No 650687034: Global MASTER-Net observations report
  49. GRB 210812A is consistent with being a lensed GRB
  50. GRB 210712A: Fermi GBM observation
  51. GRB 210813A: BALROG localization (Fermi Trigger 650508868 / GRB 210813038)
  52. Fermi GRB 210813A: Global MASTER-Net observations report
  53. GRB 210813A: Fermi GBM Final Real-time Localization
  54. Fermi-LAT Gamma-ray Observations of IceCube-210811A
  55. Retraction of Fermi GBM GCN 30630 and GCN 30632
  56. Fermi GRB 210812A: Global MASTER-Net observations report
  57. GRB 210812B: Fermi GBM Final Real-time Localization
  58. GRB 210812A: BALROG localization (Fermi Trigger 650479626 / GRB 210812699)
  59. GRB 210812A: Fermi GBM Final Real-time Localization
  60. GRB 080102A: Fermi GBM Final Real-time Localization
  61. GRB 080101A: Fermi GBM Final Real-time Localization
  62. IceCube-210811A - IceCube observation of a high-energy neutrino candidate track-like event
  63. GRB 210802A: Further Swift/XRT observation and afterglow confirmation
  64. GRB 210807C: Fermi GBM detection
  65. Fermi GRB 210807C: Global MASTER-Net observations report
  66. GRB 210807C: Fermi GBM Final Real-time Localization
  67. Fermi GRB 210807B: Global MASTER-Net observations report
  68. Fermi trigger No 650046564: Global MASTER-Net observations report
  69. GRB 210807B: Fermi GBM Final Real-time Localization
  70. Fermi trigger No 649814537: Global MASTER-Net observations report
  71. GRB 210802A: MITSuME Okayama optical upper limits
  72. GRB 210803A: Fermi GBM observation
  73. Fermi trigger No 649684549: Global MASTER-Net observations report
  74. GRB 210802A: DDOTI Upper Limits
  75. GRB 210802A: BOOTES-2/TELMA optical upper limit
  76. GRB 210802A: Swift-XRT afterglow detection
  77. GRB 210802A: Fermi GBM detection
  78. GRB 210802A: Fermi-LAT detection
  79. GRB 210803A: BALROG localization (Fermi Trigger 649684549 / GRB 210803497)
  80. GRB 210802A: Tiled Swift observations
  81. Fermi trigger No 649627691: Global MASTER-Net observations report
  82. GRB 210801A: Fermi GBM detection
  83. Fermi trigger No 649524889: Global MASTER-Net observations report
  84. GRB 210801A: BALROG localization (Fermi Trigger 649519043 / GRB 210801581)
  85. Fermi trigger No 649519043: Global MASTER-Net observations report
  86. GRB 210731A: Fermi GBM Observation
  87. Fermi-LAT Gamma-ray Observations of IceCube-210730A
  88. Fermi trigger No 649390368: Global MASTER-Net observations report
  89. IceCube-210730A - IceCube observation of a high-energy neutrino candidate track-like event
  90. GRB 210730A: Fermi GBM observation
  91. Fermi trigger No 649313854: Global MASTER-Net observations report
  92. GRB 210727A: AstroSat CZTI detection
  93. Fermi GBM Sub-Threshold Detection of GRB 210725B
  94. IPN triangulation of GRB 210727A (short)
  95. Fermi GBM Sub-Threshold Detection of GRB 210726A
  96. GRB 210714A: Fermi GBM observation
  97. GRB 210727A: AGILE/MCAL detection
  98. Fermi trigger No 649072251: Global MASTER-Net observations report
  99. GRB 210727A: BALROG localization (Fermi Trigger 649072251 / GRB 210727410)
  100. Fermi trigger No 648959581: Global MASTER-Net observations report

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