Skip to main content
Testing. You are viewing the public testing version of GCN. For the production version, go to https://gcn.nasa.gov.
New! BOOM Notices and Schema v7.0.0. 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"
  1. GRB 200713A: Enhanced Swift-XRT position
  2. GRB 200713A: Swift detection of a burst
  3. GRB 200711A: CALET Gamma-Ray Burst Monitor detection
  4. GRB 200711A: AbAO optical upper limit
  5. GRB 200711A: Swift/UVOT Upper Limits
  6. GRB 200711A: Swift-BAT refined analysis
  7. GRB 200711A: Fermi-LAT marginal detection
  8. GRB 200711A: KAIT Optical Upper Limit
  9. GRB 200711A: Swift-XRT refined Analysis
  10. GRB 200711A: Fermi GBM detection
  11. Swift GRB 200711A: Global MASTER-Net observations report
  12. GRB 200711A: Swift detection of a burst
  13. GRB 200711A: Fermi GBM Final Real-time Localization
  14. Update of alert from the HAWC Burst Monitor HAWC-200709A
  15. GRB 200709B/HAWC-200907A: Swift-XRT further observations
  16. HAWC-200907A: No Neutrino Counterpart detected with ANTARES
  17. GRB 200710A: Fermi GBM Final Real-time Localization
  18. GRB 200709B: Swift-XRT observations
  19. GRB 200709B: Tiled Swift observations
  20. GRB 200709A: Fermi GBM Final Real-time Localization
  21. GRB 200707A: Insight-HXMT/HE detection
  22. GRB 200707A: Fermi GBM Final Localization
  23. Fermi trigger No 615741133: Global MASTER-Net observations report
  24. GRB 200704A: Insight-HXMT/HE detection
  25. GRB 200706A: Fermi GBM Final Real-time Localization
  26. Fermi GRB 200705A: Global MASTER-Net observations report
  27. Fermi-LAT-ANTARES 200407a Coincidence
  28. GRB 200705A: Fermi GBM Final Real-time Localization
  29. GRB 200703B: Insight-HXMT/HE detection
  30. GRB 200703B: AstroSat CZTI detection
  31. GRB 200703B: Fermi GBM Final Real-time Localization
  32. GRB 200703A: Fermi GBM Final Real-time Localization
  33. Fermi GRB 200702A: Global MASTER-Net observations report
  34. GRB 200702A: Fermi GBM Final Real-time Localization
  35. Trigger 980513: Swift detection of SGR Swift J1818.0-1607
  36. GRB 200701A: Swift-BAT refined analysis
  37. Fermi-GBM Sub-Threshold Detection of GRB 200701A
  38. GRB 200701A: Swift detection of a burst
  39. GRB 200630A: Swift-BAT refined analysis
  40. GRB 200630A: Swift/UVOT Upper Limits
  41. GRB 200630A: Swift-XRT refined Analysis
  42. GRB 200630B: Fermi GBM Final Localization
  43. GRB 200623A: Swift XRT further observations
  44. GRB 200630A: Fermi GBM detection
  45. GRB 200629A: AstroSat CZTI detection
  46. GRB 200630A: Enhanced Swift-XRT position
  47. GRB 200630A: Swift detection of a burst
  48. Fermi trigger No 615174580: Global MASTER-Net observations report
  49. Fermi GRB 200629A: Global MASTER-Net observations report
  50. GRB 200629A: Fermi GBM Final Real-time Localization
  51. GRB 200629A: BALROG localization (Fermi Trigger 615127794 / GRB 200629535)
  52. GRB 200522A: Gemini North spectroscopy of the putative host galaxy
  53. Konus-Wind detection of short/hard GRB 200623B
  54. GRB 200623A: Further MMTCam Observations of XRT Source #3
  55. GRB 200625A: Fermi-LAT detection is likely a flare from PKS 1127-14
  56. GRB 200623A: LBT optical observations
  57. GRB 200623A : SMA observations at Swift/XRT Source #3
  58. Fermi GRB 200626A: Global MASTER-Net observations report
  59. GRB 200625A: Swift ToO observations
  60. GRB 200626A: Fermi GBM Final Real-time Localization
  61. Fermi GRB 200625A: Global MASTER-Net observations report
  62. GRB 200625A: Fermi GBM Final Real-time Localization
  63. Updated catalog of X-ray bursts of SGR J1935+2154 from Insight-HXMT observations
  64. GRB 200623A: MMT observations at XRT Source #3
  65. GRB 200623A: Swift/UVOT Upper Limits
  66. IPN triangulation of GRB 200623B (short)
  67. GRB 200623A: Swift-XRT observations
  68. GRB 200623A: OAJ deep multi-color imaging, XRT #2 is pre-detected
  69. GRB 200623A: TNG optical observations
  70. GRB 200623A: AbAO afterglow candidate within XRT #2
  71. GRB 200623A: Fermi GBM observation
  72. Fermi GRB 200623B: Global MASTER-Net observations report
  73. GRB 200623B: Fermi GBM Final Real-time Localization
  74. GRB 200623A: Correction to GCN 28013
  75. GRB 200623A: Swift ToO observations
  76. IceCube-200620A: No significant detection in HAWC
  77. GRB 200623A: Swift/BAT-GUANO detection and arcminute localization of a short GRB
  78. Fermi GRB 200623A: Global MASTER-Net observations report
  79. GRB 200623A: Fermi GBM Final Real-time Localization
  80. IceCube-200620A: Upper limits from a search for additional neutrino events in IceCube
  81. IceCube-200620A: INTEGRAL was inactive at the time of the event
  82. GRB 200622A: Fermi GBM Final Real-time Localization
  83. IceCube-200620A: MASTER previous detection of ZTF20abgvabi/AT2020ncr
  84. IceCube-200620A: not observable by Fermi-GBM
  85. IceCube-200620A: One Candidate Counterpart from the Zwicky Transient Facility
  86. Fermi-LAT Gamma-ray Observations of IceCube-200620A
  87. GRB 200613A: Continued CrAO optical observations
  88. IceCube-200620A: No ANTARES neutrino counterpart
  89. IceCube Alert 200620.13: Global MASTER-Net observations report
  90. GRB 200613A: CrAO optical observations
  91. GRB 200613A: R-band observations from HCT
  92. GRB 200613A: Further Liverpool Telescope observations
  93. IceCube-200620A - IceCube observation of a high-energy neutrino candidate track-like event
  94. GRB 200619C: Fermi GBM Final Real-time Localization
  95. Fermi GRB 200619B: Global MASTER-Net observations report
  96. GRB 200619B: AstroSat CZTI detection
  97. GRB 200619A: Fermi GBM observation
  98. Fermi trigger No 614239407: Global MASTER-Net observations report
  99. GRB 200619A: AGILE detection
  100. LIGO/Virgo MS200618aq: Retraction of a test binary neutron star candidate

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