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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"

11529 results found.

  1. GRB 210801A: BALROG localization (Fermi Trigger 649519043 / GRB 210801581)
  2. Fermi trigger No 649519043: Global MASTER-Net observations report
  3. GRB 210731A: Fermi GBM Observation
  4. Fermi-LAT Gamma-ray Observations of IceCube-210730A
  5. Fermi trigger No 649390368: Global MASTER-Net observations report
  6. IceCube-210730A - IceCube observation of a high-energy neutrino candidate track-like event
  7. GRB 210730A: Fermi GBM observation
  8. Fermi trigger No 649313854: Global MASTER-Net observations report
  9. GRB 210727A: AstroSat CZTI detection
  10. Fermi GBM Sub-Threshold Detection of GRB 210725B
  11. IPN triangulation of GRB 210727A (short)
  12. Fermi GBM Sub-Threshold Detection of GRB 210726A
  13. GRB 210714A: Fermi GBM observation
  14. GRB 210727A: AGILE/MCAL detection
  15. Fermi trigger No 649072251: Global MASTER-Net observations report
  16. GRB 210727A: BALROG localization (Fermi Trigger 649072251 / GRB 210727410)
  17. Fermi trigger No 648959581: Global MASTER-Net observations report
  18. GRB 210725A: Fermi GBM detection
  19. GRB 210723A: CALET Gamma-Ray Burst Monitor detection
  20. Fermi trigger No 648868114: Global MASTER-Net observations report
  21. GRB 210723A: Fermi GBM Observation
  22. GRB 210722A: Fermi GBM observation
  23. Fermi trigger No 648602917: Global MASTER-Net observations report
  24. Fermi-LAT Gamma-ray Observations of IceCube-210717A
  25. Fermi trigger No 648359752: Global MASTER-Net observations report
  26. Fermi trigger No 648278666: Global MASTER-Net observations report
  27. IceCube-210717A: IceCube observation of a high-energy neutrino candidate track-like event
  28. Konus-Wind detection of GRB 210714A
  29. Fermi trigger No 647942198: MASTER optical afterglow detection
  30. GRB 210715B: DDOTI Upper Limits on the Afterglow
  31. Fermi trigger No 648033323: Global MASTER-Net observations report
  32. Fermi trigger No 648024201: Global MASTER-Net observations report
  33. Fermi trigger No 647942198: Global MASTER-Net observations report
  34. Recent activity of SGR 1935+2154 as observed by CGBM
  35. Fermi trigger No 647805873: Global MASTER-Net observations report
  36. GRB 210704A: classification as long GRB and redshift estimating
  37. Konus-Wind detection of a burst from SGR 1935+2154 on 2021 July 10
  38. Fermi trigger No 647775795: Global MASTER-Net observations report
  39. GRB 210709A: AstroSat CZTI detection
  40. GRB 210704A: INTEGRAL observations
  41. Fermi trigger No 647653174: Global MASTER-Net observations report
  42. Fermi trigger No 647641569: Global MASTER-Net observations report
  43. Fermi trigger No 647624281: Global MASTER-Net observations report
  44. Fermi trigger No 647522278: Global MASTER-Net observations report
  45. GRB 210706A: Swift/XRT afterglow confirmation
  46. Fermi GRB 210709A: Global MASTER-Net observations report
  47. GRB 210709A: Fermi GBM Final Real-time Localization
  48. Fermi GBM Sub-Threshold Detection of GRB 210708A
  49. Fermi GBM Sub-Threshold Detection of GRB 210707A
  50. Konus-Wind detection of a burst from SGR 1935+2154 on 2021 July 7
  51. GRB 210704A: CAHA 2.2m telescope optical limit
  52. Fermi trigger No 647365516: Global MASTER-Net observations report
  53. Fermi trigger No 647271699: Global MASTER-Net observations report
  54. Fermi GBM Observations of SGR J1935+2154
  55. GRB 210706A: Fermi GBM observation
  56. Konus-Wind detection of GRB 210706A
  57. GRB 210704A: OAJ T80 multi-color detections
  58. GECAM detection of a bright short burst from SGR 1935+2154
  59. Fermi trigger No 647252274: Global MASTER-Net observations report
  60. GRB 210706A: Swift/BAT-GUANO detection and arcminute localization
  61. GRB 210704A: OSIRIS/GTC spectroscopy
  62. GRB 210704A: CAHA 2.2m Afterglow Detection
  63. Konus-Wind detection of GRB 210704A
  64. GRB 210704B: AstroSat CZTI detection
  65. GRB 210704A: Assy optical afterglow candidate
  66. GRB 210704A: DDOTI upper limit
  67. GRB 210704B: Fermi GBM detection
  68. GRB 210704A: possible local hosts
  69. GRB 210704A: Fermi GBM detection
  70. GRB 210704A: Swift-XRT afterglow detection
  71. GRB 210704A: AstroSat CZTI detection
  72. GRB 210704A: Fermi-LAT detection
  73. GRB 210704A: Swift ToO observations
  74. GRB 210704A: AGILE/MCAL detection
  75. Fermi trigger No 647108723: Global MASTER-Net observations report
  76. Fermi trigger No 647120009: Global MASTER-Net observations report
  77. GRB 210704A: BALROG localization (Fermi Trigger 647120009 / GRB 210704815)
  78. Fermi-LAT Gamma-ray Observations of IceCube-210629A
  79. IceCube-210629A: Upper limits from Fermi-GBM Observations
  80. GRB 210627B: GECAM detection
  81. GRB 210619B: Sayan observatory 1.6-m telescope observations
  82. IceCube-210629A - IceCube observation of a high-energy neutrino candidate track-like event
  83. GRB 210626A: Swift/XRT afterglow confirmation
  84. GRB 210626A: Fermi GBM observation
  85. GRB 210626A: CAHA 2.2m telescope optical limit
  86. GRB 210626A: Ondrejov D50 optical limit
  87. GRB 210626A: GIT optical upper limit
  88. Fermi trigger No 646443989: Global MASTER-Net observations report
  89. Fermi GRB 210627B: Global MASTER-Net observations report
  90. GRB 210627B: BALROG localization (Fermi Trigger 646509445/ GRB 210627748)
  91. GRB 210627B: Fermi GBM Final Real-time Localization
  92. Fermi GRB 210627A: Global MASTER-Net observations report
  93. GRB 210627A: Fermi GBM Final Real-time Localization
  94. Fermi trigger No 646322348: Global MASTER-Net observations report
  95. Fermi GRB 210626A: Global MASTER-Net observations report
  96. GRB 210626A: Swift/BAT-GUANO detection and arcminute localization
  97. GRB 210626A: Fermi GBM Final Real-time Localization
  98. GRB 210618A: 1.5m OSN optical upper limit
  99. Fermi GRB 210625A: Global MASTER-Net observations report
  100. GRB 210625A: Fermi GBM Final Real-time Localization

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