Skip to main content
Updates to LVK & CHIME Notices, Schema v7.2.3! See news and announcements

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"

11514 results found.

  1. GRB 210727A: BALROG localization (Fermi Trigger 649072251 / GRB 210727410)
  2. Fermi trigger No 648959581: Global MASTER-Net observations report
  3. GRB 210725A: Fermi GBM detection
  4. GRB 210723A: CALET Gamma-Ray Burst Monitor detection
  5. Fermi trigger No 648868114: Global MASTER-Net observations report
  6. GRB 210723A: Fermi GBM Observation
  7. GRB 210722A: Fermi GBM observation
  8. Fermi trigger No 648602917: Global MASTER-Net observations report
  9. Fermi-LAT Gamma-ray Observations of IceCube-210717A
  10. Fermi trigger No 648359752: Global MASTER-Net observations report
  11. Fermi trigger No 648278666: Global MASTER-Net observations report
  12. IceCube-210717A: IceCube observation of a high-energy neutrino candidate track-like event
  13. Konus-Wind detection of GRB 210714A
  14. Fermi trigger No 647942198: MASTER optical afterglow detection
  15. GRB 210715B: DDOTI Upper Limits on the Afterglow
  16. Fermi trigger No 648033323: Global MASTER-Net observations report
  17. Fermi trigger No 648024201: Global MASTER-Net observations report
  18. Fermi trigger No 647942198: Global MASTER-Net observations report
  19. Recent activity of SGR 1935+2154 as observed by CGBM
  20. Fermi trigger No 647805873: Global MASTER-Net observations report
  21. GRB 210704A: classification as long GRB and redshift estimating
  22. Konus-Wind detection of a burst from SGR 1935+2154 on 2021 July 10
  23. Fermi trigger No 647775795: Global MASTER-Net observations report
  24. GRB 210709A: AstroSat CZTI detection
  25. GRB 210704A: INTEGRAL observations
  26. Fermi trigger No 647653174: Global MASTER-Net observations report
  27. Fermi trigger No 647641569: Global MASTER-Net observations report
  28. Fermi trigger No 647624281: Global MASTER-Net observations report
  29. Fermi trigger No 647522278: Global MASTER-Net observations report
  30. GRB 210706A: Swift/XRT afterglow confirmation
  31. Fermi GRB 210709A: Global MASTER-Net observations report
  32. GRB 210709A: Fermi GBM Final Real-time Localization
  33. Fermi GBM Sub-Threshold Detection of GRB 210708A
  34. Fermi GBM Sub-Threshold Detection of GRB 210707A
  35. Konus-Wind detection of a burst from SGR 1935+2154 on 2021 July 7
  36. GRB 210704A: CAHA 2.2m telescope optical limit
  37. Fermi trigger No 647365516: Global MASTER-Net observations report
  38. Fermi trigger No 647271699: Global MASTER-Net observations report
  39. Fermi GBM Observations of SGR J1935+2154
  40. GRB 210706A: Fermi GBM observation
  41. Konus-Wind detection of GRB 210706A
  42. GRB 210704A: OAJ T80 multi-color detections
  43. GECAM detection of a bright short burst from SGR 1935+2154
  44. Fermi trigger No 647252274: Global MASTER-Net observations report
  45. GRB 210706A: Swift/BAT-GUANO detection and arcminute localization
  46. GRB 210704A: OSIRIS/GTC spectroscopy
  47. GRB 210704A: CAHA 2.2m Afterglow Detection
  48. Konus-Wind detection of GRB 210704A
  49. GRB 210704B: AstroSat CZTI detection
  50. GRB 210704A: Assy optical afterglow candidate
  51. GRB 210704A: DDOTI upper limit
  52. GRB 210704B: Fermi GBM detection
  53. GRB 210704A: possible local hosts
  54. GRB 210704A: Fermi GBM detection
  55. GRB 210704A: Swift-XRT afterglow detection
  56. GRB 210704A: AstroSat CZTI detection
  57. GRB 210704A: Fermi-LAT detection
  58. GRB 210704A: Swift ToO observations
  59. GRB 210704A: AGILE/MCAL detection
  60. Fermi trigger No 647108723: Global MASTER-Net observations report
  61. Fermi trigger No 647120009: Global MASTER-Net observations report
  62. GRB 210704A: BALROG localization (Fermi Trigger 647120009 / GRB 210704815)
  63. Fermi-LAT Gamma-ray Observations of IceCube-210629A
  64. IceCube-210629A: Upper limits from Fermi-GBM Observations
  65. GRB 210627B: GECAM detection
  66. GRB 210619B: Sayan observatory 1.6-m telescope observations
  67. IceCube-210629A - IceCube observation of a high-energy neutrino candidate track-like event
  68. GRB 210626A: Swift/XRT afterglow confirmation
  69. GRB 210626A: Fermi GBM observation
  70. GRB 210626A: CAHA 2.2m telescope optical limit
  71. GRB 210626A: Ondrejov D50 optical limit
  72. GRB 210626A: GIT optical upper limit
  73. Fermi trigger No 646443989: Global MASTER-Net observations report
  74. Fermi GRB 210627B: Global MASTER-Net observations report
  75. GRB 210627B: BALROG localization (Fermi Trigger 646509445/ GRB 210627748)
  76. GRB 210627B: Fermi GBM Final Real-time Localization
  77. Fermi GRB 210627A: Global MASTER-Net observations report
  78. GRB 210627A: Fermi GBM Final Real-time Localization
  79. Fermi trigger No 646322348: Global MASTER-Net observations report
  80. Fermi GRB 210626A: Global MASTER-Net observations report
  81. GRB 210626A: Swift/BAT-GUANO detection and arcminute localization
  82. GRB 210626A: Fermi GBM Final Real-time Localization
  83. GRB 210618A: 1.5m OSN optical upper limit
  84. Fermi GRB 210625A: Global MASTER-Net observations report
  85. GRB 210625A: Fermi GBM Final Real-time Localization
  86. IPN triangulation of GRB 210624A (short)
  87. GRB 210619B: ASIM observation
  88. Fermi trigger No 646189108: Global MASTER-Net observations report
  89. Fermi GBM observation of a bright burst in the direction of SGR 1935+2154
  90. Fermi trigger No 646194855: Global MASTER-Net observations report
  91. Fermi GRB 210622B: Global MASTER-Net observations report
  92. GRB 210622A: Fermi GBM detection
  93. GRB 210619B: SPI-ACS/INTEGRAL observations
  94. GRB 210622A: Swift/BAT-GUANO detection and arcminute localization of a long burst
  95. GECAM detection of GRB 210622B
  96. GRB 210622B: Fermi GBM Final Real-time Localization
  97. GRB 210622A: Fermi GBM Final Real-time Localization
  98. GRB 210619B: 1.5m OSN optical observation
  99. Fermi GRB 210621A: Global MASTER-Net observations report
  100. GRB 210621A: Fermi GBM Final Real-time Localization

Advanced

Download all Circulars as a .tar.gz archive (updated once a day):
Questions or comments?
Contact GCN directly.
Have you found a bug in GCN?
Open an issue.
Want to contribute code to GCN?
Get involved on GitHub.

gcn.nasa.gov

A service of the Astrophysics Science Division at NASA Goddard Space Flight Center

Looking for U.S. government information and services? Visit USA.gov