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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"

11523 results found.

  1. GRB 210730A: Fermi GBM observation
  2. Fermi trigger No 649313854: Global MASTER-Net observations report
  3. GRB 210727A: AstroSat CZTI detection
  4. Fermi GBM Sub-Threshold Detection of GRB 210725B
  5. IPN triangulation of GRB 210727A (short)
  6. Fermi GBM Sub-Threshold Detection of GRB 210726A
  7. GRB 210714A: Fermi GBM observation
  8. GRB 210727A: AGILE/MCAL detection
  9. Fermi trigger No 649072251: Global MASTER-Net observations report
  10. GRB 210727A: BALROG localization (Fermi Trigger 649072251 / GRB 210727410)
  11. Fermi trigger No 648959581: Global MASTER-Net observations report
  12. GRB 210725A: Fermi GBM detection
  13. GRB 210723A: CALET Gamma-Ray Burst Monitor detection
  14. Fermi trigger No 648868114: Global MASTER-Net observations report
  15. GRB 210723A: Fermi GBM Observation
  16. GRB 210722A: Fermi GBM observation
  17. Fermi trigger No 648602917: Global MASTER-Net observations report
  18. Fermi-LAT Gamma-ray Observations of IceCube-210717A
  19. Fermi trigger No 648359752: Global MASTER-Net observations report
  20. Fermi trigger No 648278666: Global MASTER-Net observations report
  21. IceCube-210717A: IceCube observation of a high-energy neutrino candidate track-like event
  22. Konus-Wind detection of GRB 210714A
  23. Fermi trigger No 647942198: MASTER optical afterglow detection
  24. GRB 210715B: DDOTI Upper Limits on the Afterglow
  25. Fermi trigger No 648033323: Global MASTER-Net observations report
  26. Fermi trigger No 648024201: Global MASTER-Net observations report
  27. Fermi trigger No 647942198: Global MASTER-Net observations report
  28. Recent activity of SGR 1935+2154 as observed by CGBM
  29. Fermi trigger No 647805873: Global MASTER-Net observations report
  30. GRB 210704A: classification as long GRB and redshift estimating
  31. Konus-Wind detection of a burst from SGR 1935+2154 on 2021 July 10
  32. Fermi trigger No 647775795: Global MASTER-Net observations report
  33. GRB 210709A: AstroSat CZTI detection
  34. GRB 210704A: INTEGRAL observations
  35. Fermi trigger No 647653174: Global MASTER-Net observations report
  36. Fermi trigger No 647641569: Global MASTER-Net observations report
  37. Fermi trigger No 647624281: Global MASTER-Net observations report
  38. Fermi trigger No 647522278: Global MASTER-Net observations report
  39. GRB 210706A: Swift/XRT afterglow confirmation
  40. Fermi GRB 210709A: Global MASTER-Net observations report
  41. GRB 210709A: Fermi GBM Final Real-time Localization
  42. Fermi GBM Sub-Threshold Detection of GRB 210708A
  43. Fermi GBM Sub-Threshold Detection of GRB 210707A
  44. Konus-Wind detection of a burst from SGR 1935+2154 on 2021 July 7
  45. GRB 210704A: CAHA 2.2m telescope optical limit
  46. Fermi trigger No 647365516: Global MASTER-Net observations report
  47. Fermi trigger No 647271699: Global MASTER-Net observations report
  48. Fermi GBM Observations of SGR J1935+2154
  49. GRB 210706A: Fermi GBM observation
  50. Konus-Wind detection of GRB 210706A
  51. GRB 210704A: OAJ T80 multi-color detections
  52. GECAM detection of a bright short burst from SGR 1935+2154
  53. Fermi trigger No 647252274: Global MASTER-Net observations report
  54. GRB 210706A: Swift/BAT-GUANO detection and arcminute localization
  55. GRB 210704A: OSIRIS/GTC spectroscopy
  56. GRB 210704A: CAHA 2.2m Afterglow Detection
  57. Konus-Wind detection of GRB 210704A
  58. GRB 210704B: AstroSat CZTI detection
  59. GRB 210704A: Assy optical afterglow candidate
  60. GRB 210704A: DDOTI upper limit
  61. GRB 210704B: Fermi GBM detection
  62. GRB 210704A: possible local hosts
  63. GRB 210704A: Fermi GBM detection
  64. GRB 210704A: Swift-XRT afterglow detection
  65. GRB 210704A: AstroSat CZTI detection
  66. GRB 210704A: Fermi-LAT detection
  67. GRB 210704A: Swift ToO observations
  68. GRB 210704A: AGILE/MCAL detection
  69. Fermi trigger No 647108723: Global MASTER-Net observations report
  70. Fermi trigger No 647120009: Global MASTER-Net observations report
  71. GRB 210704A: BALROG localization (Fermi Trigger 647120009 / GRB 210704815)
  72. Fermi-LAT Gamma-ray Observations of IceCube-210629A
  73. IceCube-210629A: Upper limits from Fermi-GBM Observations
  74. GRB 210627B: GECAM detection
  75. GRB 210619B: Sayan observatory 1.6-m telescope observations
  76. IceCube-210629A - IceCube observation of a high-energy neutrino candidate track-like event
  77. GRB 210626A: Swift/XRT afterglow confirmation
  78. GRB 210626A: Fermi GBM observation
  79. GRB 210626A: CAHA 2.2m telescope optical limit
  80. GRB 210626A: Ondrejov D50 optical limit
  81. GRB 210626A: GIT optical upper limit
  82. Fermi trigger No 646443989: Global MASTER-Net observations report
  83. Fermi GRB 210627B: Global MASTER-Net observations report
  84. GRB 210627B: BALROG localization (Fermi Trigger 646509445/ GRB 210627748)
  85. GRB 210627B: Fermi GBM Final Real-time Localization
  86. Fermi GRB 210627A: Global MASTER-Net observations report
  87. GRB 210627A: Fermi GBM Final Real-time Localization
  88. Fermi trigger No 646322348: Global MASTER-Net observations report
  89. Fermi GRB 210626A: Global MASTER-Net observations report
  90. GRB 210626A: Swift/BAT-GUANO detection and arcminute localization
  91. GRB 210626A: Fermi GBM Final Real-time Localization
  92. GRB 210618A: 1.5m OSN optical upper limit
  93. Fermi GRB 210625A: Global MASTER-Net observations report
  94. GRB 210625A: Fermi GBM Final Real-time Localization
  95. IPN triangulation of GRB 210624A (short)
  96. GRB 210619B: ASIM observation
  97. Fermi trigger No 646189108: Global MASTER-Net observations report
  98. Fermi GBM observation of a bright burst in the direction of SGR 1935+2154
  99. Fermi trigger No 646194855: Global MASTER-Net observations report
  100. Fermi GRB 210622B: Global MASTER-Net observations report

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