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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. GRB 201222A: Fermi GBM Final Real-time Localization
  2. GRB 201221E: Fermi GBM Final Real-time Localization
  3. correction to GCN 29110 - Fermi GBM Sub-Threshold Detection of GRB 201221A
  4. Fermi GBM Sub-Threshold Detection of GRB 201221A
  5. IceCube-201221A: not observable by Fermi-GBM
  6. IceCube-201221A: IceCube observation of a high-energy neutrino candidate event
  7. GRB 201221B: Fermi GBM Final Real-time Localization
  8. Konus-Wind observation of GRB 201218A
  9. IPN triangulation of GRB 201218A
  10. Fermi GRB 201218B: Global MASTER-Net observations report
  11. GRB 201218B: Fermi GBM Final Real-time Localization
  12. Fermi GRB 201218A: Global MASTER-Net observations report
  13. GRB201216C: No significant detection in HAWC
  14. Konus-Wind detection of GRB 201216C
  15. GRB 201218A: BALROG localization (Fermi Trigger 629957660 / GRB 201218177)
  16. GRB 201218A: Fermi GBM Final Real-time Localization
  17. Fermi GRB 201217A: Global MASTER-Net observations report
  18. GRB 201217A: Fermi GBM Final Localization
  19. GRB 201216C: VLT X-shooter spectroscopy and potential high redshift of a VHE-emitting GRB
  20. GRB 201216C: Fermi-LAT upper limit
  21. GRB 201216C: MAGIC detection in very high energy gamma rays
  22. GRB 201216C: AstroSat CZTI detection
  23. GRB 201216C: Fermi GBM detection
  24. GRB 201216A: Fermi GBM detection
  25. GRB 201216C: FRAM-ORM afterglow confirmation
  26. GRB 201216A: Swift-XRT observations
  27. GRB 201216C: VLT afterglow candidate discovery
  28. GRB 201216C: Fermi GBM Final Real-time Localization
  29. Fermi GRB 201216A: Global MASTER-Net observations report
  30. GRB 201216A: Swift/BAT-GUANO detection and arcminute localization
  31. GRB 201216A: Fermi GBM Final Real-time Localization
  32. GRB 201214B: MITSuME Akeno optical upper limits
  33. GRB 201214B: Lowell Discovery Telescope optical observations
  34. Fermi GRB 201215A: Global MASTER-Net observations report
  35. GRB 201215A: BALROG localization (Fermi Trigger 629706213 / GRB 201215266)
  36. GRB 201215A: Fermi GBM Final Real-time Localization
  37. GRB 201214B: Swift BAT location of short burst
  38. Fermi GRB 201214B: Global MASTER-Net observations report
  39. GRB 201214B: Fermi GBM Final Real-time Localization
  40. GRB 201213A: Fermi GBM Final Real-time Localization
  41. IceCube-201209A: Upper limits from Fermi-GBM Observations
  42. Fermi-LAT Gamma-ray Observations of IceCube-201209A
  43. IPN triangulation of GRB 201207A
  44. GRB 201208A: Swift-XRT afterglow detection
  45. GRB 201208A: Fermi GBM observation
  46. GRB 201208A: LCO observations
  47. IceCube-201209A: IceCube observation of a high-energy neutrino candidate event
  48. GRB 201207A: AGILE detection
  49. GRB 201208A: Fermi-LAT detection
  50. GRB 201208A: Swift ToO observations
  51. GRB 201208A: AstroSat CZTI detection
  52. GRB 201207A: AstroSat CZTI detection
  53. Fermi GRB 201208A: Global MASTER-Net observations report
  54. GRB 201208A: Fermi GBM Final Real-time Localization
  55. Fermi GRB 201207A: Global MASTER-Net observations report
  56. GRB 201207A: Fermi GBM Final Real-time Localization
  57. Swift follow-up observations of the flat spectrum radio quasar PMN J0206-1150 in the error region of IceCube-201130A
  58. GRB201130A: Zwicky Transient Facility Follow-Up of a Fermi Short GRB (Trigger 628407054)
  59. Swift observations of the Fermi-LAT source 4FGL J0206.4-1151 in the error region of IceCube-201130A
  60. Fermi-LAT Gamma-ray Observations of IceCube-201130A
  61. IceCube-201130A: Not observable by Fermi-GBM
  62. GRB 201201A: DDOTI Observations
  63. Fermi GRB 201201A: Global MASTER-Net observations report
  64. GRB 201201A: Fermi GBM Final Real-time Localization
  65. GRB 201128B: Swift/BAT-GUANO detection and arcminute localization
  66. IceCube-201130A: IceCube observation of a high-energy neutrino candidate event
  67. GRB 201130A: DDOTI Observations
  68. Fermi GRB 201130A: Global MASTER-Net observations report
  69. GRB 201130A: Fermi GBM Final Real-time Localization
  70. Fermi trigger No 628278856: Global MASTER-Net observations report
  71. Fermi trigger No 628140709: DDOTI/OAN optical observations report
  72. Fermi trigger No 628140709: Global MASTER-Net observations report
  73. GRB 201121A: Insight-HXMT/HE detection
  74. GRB 200826A: TNG and LBT constraints on a supernova bump
  75. IceCube-201114A: DECam observations and candidate optical counterpart
  76. Fermi-LAT Gamma-ray Observations of IceCube-201120A
  77. Fermi trigger No 627645769: Global MASTER-Net observations report
  78. IceCube-201120A: Swift-XRT non-detection of 4FGL J2028.6+4110e
  79. Fermi GRB 201121A: Global MASTER-Net observations report
  80. GRB 201121B: Fermi GBM Final Real-time Localization
  81. GRB 201121A: BALROG localization (Fermi Trigger 627614994 / GRB 201121062)
  82. GRB 201121A: Fermi GBM Final Real-time Localization
  83. Fermi GRB 201120B: Global MASTER-Net observations report
  84. GRB 201120B: Fermi GBM Final Localization
  85. GRB 201120A: Fermi GBM Final Localization
  86. IceCube-201120A: Upper limits from Fermi-GBM Observations
  87. Fermi trigger No 627557935: Global MASTER-Net observations report
  88. IceCube-201120A: IceCube observation of a high-energy neutrino candidate event
  89. IceCube 201114A: Swift followup of Fermi J0703.5+0505
  90. GRB 201116A: CALET Gamma-Ray Burst Monitor detection
  91. Fermi trigger No 627438255: Global MASTER-Net observations report
  92. Konus-Wind detection of GRB 201116A
  93. Fermi-LAT Gamma-ray Observations of IceCube-201114A
  94. GRB 201116A: NOT optical observations
  95. GRB 201116A: Swift-XRT afterglow detection
  96. GRB 201116A: OSN Afterglow Candidate
  97. Fermi trigger No 627198169: Global MASTER-Net observations report
  98. IceCube-201114A: No significant detection in HAWC
  99. GRB 201116A: Fermi-LAT detection
  100. GRB 201116A: Tiled Swift observations

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