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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"

11099 results found.

  1. GRB 201109A: Fermi GBM detection
  2. GRB 201104A: AstroSat CZTI detection
  3. Fermi GRB 201109A: Global MASTER-Net observations report
  4. GRB 201109A: Fermi GBM Final Real-time Localization
  5. Fermi GRB 201108A: Global MASTER-Net observations report
  6. GRB 201108A: Fermi GBM Final Real-time Localization
  7. Konus-Wind detection of GRB 201105A
  8. GRB 201104A: Swift-XRT observations
  9. Correction to GCN 28843: GBM report of GRB 201105B should have been GRB 201105A
  10. Fermi trigger No 626247072: Global MASTER-Net observations report
  11. GRB 201105B: Fermi GBM observation
  12. GRB 201105A: BALROG localization (Fermi Trigger 626247072 / GRB 201105230)
  13. GRB 201104A: BALROG localization (Fermi Trigger 626140861 / GRB 201104001)
  14. GRB 201104C: Fermi GBM Final Real-time Localization
  15. GRB 201104A: Tiled Swift observations
  16. GRB 201104A: Fermi GBM observation
  17. GRB 201104A: AGILE/MCAL detection
  18. GRB 201104A: Fermi-LAT detection
  19. Fermi GRB 201104A: Global MASTER-Net observations report
  20. GRB 201104A: Fermi GBM Final Real-time Localization
  21. Fermi GRB 201103A: Global MASTER-Net observations report
  22. GRB 201103A: Fermi GBM Final Real-time Localization
  23. Fermi GRB 201031B: Global MASTER-Net observations report
  24. GRB 201031B: BALROG localization (Fermi Trigger 625859489 / GRB 201031744)
  25. GRB 201031B: Fermi GBM Final Real-time Localization
  26. IceCube 201021A: Swift follow-up of Fermi J1725.5+1312
  27. GRB 201029A: Fermi GBM detection
  28. Fermi trigger No 625695596: Global MASTER-Net observations report
  29. GRB 201026A: Fermi GBM detection
  30. GRB 201020B: 1.3m DFOT continued optical follow-up observations
  31. GRB 201020B: HCT and GIT continued optical follow-up observations
  32. GRB 201020B: follow-up observations with Savelli Telescope
  33. GRB 201020B: 1.3m DFOT optical observations
  34. GRB 201020B: follow-up observations at Konkoly
  35. GRB 201020B: continued Mondy optical observations
  36. GRB 201020B: Redshift from GTC/OSIRIS
  37. IceCube-201021A: Optical counterpart of WISEA J172314.13+142101.5
  38. GRB 201020B: GROWTH-India Telescope optical observations
  39. Fermi-LAT Gamma-ray Observations of IceCube-201021A and detection of a new gamma-ray source, Fermi J1725.5+1312
  40. GRB 201020B: Konkoly Obs. optical detection
  41. GRB 201021C: Fermi GBM detection
  42. Konus-Wind detection of GRB 201020A
  43. GRB 201020B: Swift/UVOT Detection
  44. GRB 201020B: Swift-XRT afterglow detection
  45. IceCube-201021A: Upper limits from Fermi-GBM Observations
  46. HAWC-201019A: not observable by Fermi-GBM
  47. GRB 201020B: Mondy optical observations
  48. Konus-Wind detection of GRB 201020B
  49. GRB 201020B: Swift ToO observations
  50. GRB 201020B: Nanshan/NEXT optical afterglow confirmation
  51. GRB 201020B: MASTER bright optical afterglow detection
  52. GRB 201020B: Fermi-LAT detection
  53. IceCube-201021A: IceCube observation of a high-energy neutrino candidate event
  54. GRB 201020B: AGILE detection
  55. GRB 201021A: Fermi GBM Final Real-time Localization
  56. GRB 201020B: Fermi GBM detection
  57. GRB 201020A: Fermi GBM observation
  58. Fermi GRB 201020B: Global MASTER-Net observations report
  59. GRB 201020B: Fermi GBM Final Real-time Localization
  60. GRB 201019B: AstroSat CZTI detection
  61. GRB 201016A: Insight-HXMT/HE detection
  62. GRB 201017A: SAO RAS optical observations
  63. GRB 201017A: GROWTH-India optical upper limit
  64. GRB 201019B: Fermi GBM correction to GCN 28687
  65. GRB 201019A: Fermi GBM Final Real-time Localization
  66. GRB 201017A: MITSuME Akeno optical upper limits
  67. GRB 201019A: Fermi GBM Final Real-time Localization
  68. GRB 201017A: Assy and Mondy optical observations, possible afterglow detection
  69. GRB 201017A: Fermi GBM detection
  70. GRB 201015A: classification as long GRB
  71. GRB 201017A: Fermi GBM Final Real-time Localization
  72. Fermi GBM Sub-Threshold Detection of GRB 201015A
  73. GRB 201016A: AstroSat CZTI detection
  74. GRB 201008A: Swift-XRT afterglow detection
  75. GRB 201016A: Fermi GBM detection
  76. Fermi GRB 201016B: Global MASTER-Net observations report
  77. GRB 201016B: BALROG localization (Fermi Trigger 624510986 / GRB 201016136)
  78. GRB 201016A: BALROG localization (Fermi Trigger 624500874 / GRB 201016019)
  79. GRB 201016B: Fermi GBM Final Real-time Localization
  80. GRB 201016A: Fermi GBM Final Real-time Localization
  81. Fermi-LAT Gamma-ray Observations of IceCube-201014A
  82. IceCube-201014A: Not observable by GBM
  83. IceCube-201014A - IceCube observation of a high-energy neutrino candidate track-like event
  84. GRB 201011A: Fermi GBM detection of a likely Long GRB in the direction of SGR 1830-0645
  85. Fermi trigger No 624139481: AGILE detection
  86. GRB 201012A: Fermi GBM Final Real-time Localization
  87. Fermi trigger No 624139481: Global MASTER-Net observations report
  88. Fermi trigger No 624121589: Global MASTER-Net observations report
  89. GRB 201008B: Fermi GBM Final Localization
  90. GRB 201008A: Swift-XRT observations
  91. GRB 201008A: Swift ToO observations
  92. IceCube-201007A: Upper limits from Fermi-GBM Observations
  93. GRB 201008A: Swift/BAT-GUANO detection and possible arcminute localization
  94. Fermi-LAT Gamma-ray Observations of IceCube-201007A
  95. Fermi trigger No 623846261: Global MASTER-Net observations report
  96. Fermi trigger No 623873165: Global MASTER-Net observations report
  97. GRB 201008A: BALROG localization (Fermi Trigger 623846261 / GRB 201008443)
  98. IceCube-201007A - IceCube observation of a high-energy neutrino candidate track-like event
  99. Fermi GRB 201007A: Global MASTER-Net observations report
  100. GRB 201007A: Fermi GBM Final Real-time Localization

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