Skip to main content
Testing. You are viewing the public testing version of GCN. For the production version, go to https://gcn.nasa.gov.
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"
  1. Fermi trigger No 624139481: AGILE detection
  2. GRB 201012A: Fermi GBM Final Real-time Localization
  3. SGR 1830-0645: pre-discovery detection in Swift/BAT
  4. Fermi trigger No 624139481: Global MASTER-Net observations report
  5. SGR 1830-0645 / GRB 201010A: 1.5m OSN optical upper limit
  6. Fermi trigger No 624121589: Global MASTER-Net observations report
  7. SGR 1830-0645: Swift-BAT refined analysis
  8. GRB 201006A: Chandra upper limit on the X-ray afterglow
  9. SGR 1830-0645 / GRB 201010A: Kitab optical non-detection
  10. GRB 201010A: Enhanced Swift-XRT position
  11. Swift GRB201010.62: Global MASTER-Net observations report
  12. Swift detection of a new SGR 1830-0645 or a short GRB 201010A
  13. IceCube-200929A: JCMT/SCUBA2 observations
  14. IceCube-201007A: No significant detection in HAWC
  15. GRB 201008B: Fermi GBM Final Localization
  16. IceCube-201007A: Upper limits from a search for additional neutrino events in IceCube
  17. GRB 201009A: AstroSat CZTI detection
  18. GRB 201009A: AGILE detection of a burst
  19. GRB 201008A: Swift-XRT observations
  20. IceCube-200926A: Upper limits from Insight-HXMT Observations
  21. GRB 201008A: Swift ToO observations
  22. IceCube-201007A: Upper limits from Fermi-GBM Observations
  23. GRB 201008A: Swift/BAT-GUANO detection and possible arcminute localization
  24. Fermi-LAT Gamma-ray Observations of IceCube-201007A
  25. Fermi trigger No 623846261: Global MASTER-Net observations report
  26. Fermi trigger No 623873165: Global MASTER-Net observations report
  27. Swift-XRT observations of IceCube 201007A
  28. Baksan Neutrino Observatory Alert 201008.47: Global MASTER-Net observations report
  29. GRB 201008A: BALROG localization (Fermi Trigger 623846261 / GRB 201008443)
  30. IceCube-201007A: No counterpart candidates in INTEGRAL SPI-ACS and IBIS prompt observation
  31. IceCube-201007A - IceCube observation of a high-energy neutrino candidate track-like event
  32. IceCube Alert 201007.92: Global MASTER-Net observations report
  33. GRB 201006A: GROWTH-India Telescope optical upper limit
  34. GRB 201006A: Lowell Discovery Telescope upper limits
  35. GRB 201006A: MITSuME Akeno optical upper limits
  36. Fermi GRB 201007A: Global MASTER-Net observations report
  37. GRB 201007A: Fermi GBM Final Real-time Localization
  38. GRB 201006A: Swift-XRT refined Analysis
  39. GRB 201006A: Swift-BAT refined analysis
  40. Baksan Neutrino Observatory Alert 201006.88: Global MASTER-Net observations report
  41. GRB 201006A: Swift/UVOT Upper Limits
  42. GRB 201006A: Fermi GBM detection
  43. GRB 201006A is likely a short burst
  44. GRB 201006A: Enhanced Swift-XRT position
  45. INTEGRAL sub-threshold detection of GRB 201006A
  46. GRB 201006A: Swift detection of a burst
  47. Swift GRB201006.05: Global MASTER-Net observations report
  48. Fermi trigger No 623470566: Global MASTER-Net observations report
  49. GRB 201004A: Fermi GBM Final Localization
  50. Fermi trigger No 623493962: Global MASTER-Net observations report
  51. GRB 201001A: Swift/UVOT Upper Limits
  52. IceCube-200926A: No usable INTEGRAL data
  53. IceCube-200926B: No counterpart candidates in INTEGRAL SPI-ACS and IBIS prompt observation
  54. IceCube-200929A: No counterpart candidates in INTEGRAL SPI-ACS and IBIS prompt observation
  55. IceCube-200926A: No candidate counterparts from the Zwicky Transient Facility
  56. GRB 201001A: TSHAO optical upper limit
  57. GRB 201001A: Xinglong-2.16m optical upper limit
  58. GRB 201001A: MITSuME Akeno optical upper limits
  59. IceCube-200926A: JCMT/SCUBA2 observations
  60. IceCube-200929A: No significant detection in HAWC
  61. GRB 201001A: Swift-BAT refined analysis
  62. GRB 201001A: Swift-XRT refined Analysis
  63. IceCube-200929A: Upper limits from a search for additional neutrino events in IceCube
  64. GRB 201001A: Fermi GBM observation
  65. Swift-XRT observations of IceCube 200929A
  66. GRB 201001A: Enhanced Swift-XRT position
  67. GRB 201001A: Swift detection of a burst
  68. GRB 201001A: Fermi GBM Final Real-time Localization
  69. Fermi-LAT Gamma-ray Observations of IceCube-200929A
  70. IceCube-200929A: Upper limits from Fermi-GBM Observations
  71. IceCube-200929A: No neutrino counterpart candidates in ANTARES search
  72. IceCube-200926B: No significant detection in HAWC
  73. GRB 200928B: Insight-HXMT/HE detection
  74. IceCube-200929A: IceCube observation of a high-energy neutrino candidate event
  75. IceCube-200926B: Upper limits from Fermi-GBM Observations
  76. IceCube-200926A: Upper limits from Fermi-GBM Observations
  77. IceCube Alert 200929.74: Global MASTER-Net observations report
  78. IceCube-200926A: No significant detection in HAWC
  79. Fermi GRB 200929A: Global MASTER-Net observations report
  80. GRB 200928B: AstroSat CZTI detection
  81. GRB 200929A: Fermi GBM Final Real-time Localization
  82. IceCube-200926B: Upper limits from a search for additional neutrino events in IceCube
  83. IceCube-200926A: Upper limits from a search for additional neutrino events in IceCube
  84. GRB 200928B: BALROG localization (Fermi Trigger 622991684 / GRB 200928552)
  85. GRB 200928B: Fermi GBM Final Real-time Localization
  86. IceCube-200926A: No Candidate Counterparts from the Zwicky Transient Facility
  87. Fermi-LAT Gamma-ray Observations of IceCube-200926B
  88. GRB 200928A: Fermi GBM Final Localization
  89. IceCube-200926B: No neutrino counterpart candidates in ANTARES search
  90. IceCube Alert 200926.94: Global MASTER-Net observations report
  91. Swift-XRT observations of IceCube 200926A
  92. Konus-Wind detection of GRB 200920B
  93. Fermi-LAT Gamma-ray Observations of IceCube-200926A
  94. GRB 200925B: Swift-XRT refined analysis update
  95. GRB 200925B NUTTelA-TAO / BSTI Early Measurements (Preliminary)
  96. IceCube Alert 200926.33: Global MASTER-Net observations report
  97. IceCube-200926B: IceCube observation of a high-energy neutrino candidate event
  98. GRB 200925B: Swift-XRT refined Analysis
  99. GRB 200925B: Swift/UVOT Detection
  100. GRB 200925B: Swift-BAT refined analysis

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