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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"

11525 results found.

  1. Fermi trigger No 649390368: Global MASTER-Net observations report
  2. IceCube-210730A - IceCube observation of a high-energy neutrino candidate track-like event
  3. GRB 210730A: Fermi GBM observation
  4. Fermi trigger No 649313854: Global MASTER-Net observations report
  5. GRB 210727A: AstroSat CZTI detection
  6. Fermi GBM Sub-Threshold Detection of GRB 210725B
  7. IPN triangulation of GRB 210727A (short)
  8. Fermi GBM Sub-Threshold Detection of GRB 210726A
  9. GRB 210714A: Fermi GBM observation
  10. GRB 210727A: AGILE/MCAL detection
  11. Fermi trigger No 649072251: Global MASTER-Net observations report
  12. GRB 210727A: BALROG localization (Fermi Trigger 649072251 / GRB 210727410)
  13. Fermi trigger No 648959581: Global MASTER-Net observations report
  14. GRB 210725A: Fermi GBM detection
  15. GRB 210723A: CALET Gamma-Ray Burst Monitor detection
  16. Fermi trigger No 648868114: Global MASTER-Net observations report
  17. GRB 210723A: Fermi GBM Observation
  18. GRB 210722A: Fermi GBM observation
  19. Fermi trigger No 648602917: Global MASTER-Net observations report
  20. Fermi-LAT Gamma-ray Observations of IceCube-210717A
  21. Fermi trigger No 648359752: Global MASTER-Net observations report
  22. Fermi trigger No 648278666: Global MASTER-Net observations report
  23. IceCube-210717A: IceCube observation of a high-energy neutrino candidate track-like event
  24. Konus-Wind detection of GRB 210714A
  25. Fermi trigger No 647942198: MASTER optical afterglow detection
  26. GRB 210715B: DDOTI Upper Limits on the Afterglow
  27. Fermi trigger No 648033323: Global MASTER-Net observations report
  28. Fermi trigger No 648024201: Global MASTER-Net observations report
  29. Fermi trigger No 647942198: Global MASTER-Net observations report
  30. Recent activity of SGR 1935+2154 as observed by CGBM
  31. Fermi trigger No 647805873: Global MASTER-Net observations report
  32. GRB 210704A: classification as long GRB and redshift estimating
  33. Konus-Wind detection of a burst from SGR 1935+2154 on 2021 July 10
  34. Fermi trigger No 647775795: Global MASTER-Net observations report
  35. GRB 210709A: AstroSat CZTI detection
  36. GRB 210704A: INTEGRAL observations
  37. Fermi trigger No 647653174: Global MASTER-Net observations report
  38. Fermi trigger No 647641569: Global MASTER-Net observations report
  39. Fermi trigger No 647624281: Global MASTER-Net observations report
  40. Fermi trigger No 647522278: Global MASTER-Net observations report
  41. GRB 210706A: Swift/XRT afterglow confirmation
  42. Fermi GRB 210709A: Global MASTER-Net observations report
  43. GRB 210709A: Fermi GBM Final Real-time Localization
  44. Fermi GBM Sub-Threshold Detection of GRB 210708A
  45. Fermi GBM Sub-Threshold Detection of GRB 210707A
  46. Konus-Wind detection of a burst from SGR 1935+2154 on 2021 July 7
  47. GRB 210704A: CAHA 2.2m telescope optical limit
  48. Fermi trigger No 647365516: Global MASTER-Net observations report
  49. Fermi trigger No 647271699: Global MASTER-Net observations report
  50. Fermi GBM Observations of SGR J1935+2154
  51. GRB 210706A: Fermi GBM observation
  52. Konus-Wind detection of GRB 210706A
  53. GRB 210704A: OAJ T80 multi-color detections
  54. GECAM detection of a bright short burst from SGR 1935+2154
  55. Fermi trigger No 647252274: Global MASTER-Net observations report
  56. GRB 210706A: Swift/BAT-GUANO detection and arcminute localization
  57. GRB 210704A: OSIRIS/GTC spectroscopy
  58. GRB 210704A: CAHA 2.2m Afterglow Detection
  59. Konus-Wind detection of GRB 210704A
  60. GRB 210704B: AstroSat CZTI detection
  61. GRB 210704A: Assy optical afterglow candidate
  62. GRB 210704A: DDOTI upper limit
  63. GRB 210704B: Fermi GBM detection
  64. GRB 210704A: possible local hosts
  65. GRB 210704A: Fermi GBM detection
  66. GRB 210704A: Swift-XRT afterglow detection
  67. GRB 210704A: AstroSat CZTI detection
  68. GRB 210704A: Fermi-LAT detection
  69. GRB 210704A: Swift ToO observations
  70. GRB 210704A: AGILE/MCAL detection
  71. Fermi trigger No 647108723: Global MASTER-Net observations report
  72. Fermi trigger No 647120009: Global MASTER-Net observations report
  73. GRB 210704A: BALROG localization (Fermi Trigger 647120009 / GRB 210704815)
  74. Fermi-LAT Gamma-ray Observations of IceCube-210629A
  75. IceCube-210629A: Upper limits from Fermi-GBM Observations
  76. GRB 210627B: GECAM detection
  77. GRB 210619B: Sayan observatory 1.6-m telescope observations
  78. IceCube-210629A - IceCube observation of a high-energy neutrino candidate track-like event
  79. GRB 210626A: Swift/XRT afterglow confirmation
  80. GRB 210626A: Fermi GBM observation
  81. GRB 210626A: CAHA 2.2m telescope optical limit
  82. GRB 210626A: Ondrejov D50 optical limit
  83. GRB 210626A: GIT optical upper limit
  84. Fermi trigger No 646443989: Global MASTER-Net observations report
  85. Fermi GRB 210627B: Global MASTER-Net observations report
  86. GRB 210627B: BALROG localization (Fermi Trigger 646509445/ GRB 210627748)
  87. GRB 210627B: Fermi GBM Final Real-time Localization
  88. Fermi GRB 210627A: Global MASTER-Net observations report
  89. GRB 210627A: Fermi GBM Final Real-time Localization
  90. Fermi trigger No 646322348: Global MASTER-Net observations report
  91. Fermi GRB 210626A: Global MASTER-Net observations report
  92. GRB 210626A: Swift/BAT-GUANO detection and arcminute localization
  93. GRB 210626A: Fermi GBM Final Real-time Localization
  94. GRB 210618A: 1.5m OSN optical upper limit
  95. Fermi GRB 210625A: Global MASTER-Net observations report
  96. GRB 210625A: Fermi GBM Final Real-time Localization
  97. IPN triangulation of GRB 210624A (short)
  98. GRB 210619B: ASIM observation
  99. Fermi trigger No 646189108: Global MASTER-Net observations report
  100. Fermi GBM observation of a bright burst in the direction of SGR 1935+2154

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