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 220713A: Fermi GBM Final Localization
  2. GRB 220714B: Swift detection of a burst
  3. GRB 220714B: Fermi GBM Final Real-time Localization
  4. GRB 220714A: Possible Swift detection of a burst
  5. GRB 220710A: Swift/UVOT Upper Limits
  6. GRB 220711C: Fermi GBM Observation
  7. Retraction of GRB 220711B: 10.4 m GTC(+EMIR) observations (GCN 32387)
  8. GRB 220711B: 10.4 m GTC(+EMIR) observations
  9. GRB 220711B: 10.4 m GTC(+EMIR) observations
  10. GRB 220710A: Swift-XRT afterglow detection
  11. GRB 220711C: Swift/BAT-GUANO detection outside the coded FOV
  12. GRB 220711B, GROND observations
  13. Konus-Wind detection of GRB 220711C
  14. GRB 220711B: NUTTelA-TAO / BSTI Early Optical Limits (Preliminary)
  15. GRB 220711B: GIT optical upper limits
  16. Fermi trigger No 679248723: Global MASTER-Net observations report
  17. Fermi GRB 220711B: Global MASTER-Net observations report
  18. GRB 220712B: NOT optical afterglow confirmation
  19. GRB 220710A: Swift ToO observations
  20. GRB 220710A: Swift/BAT-GUANO arcminute localization
  21. GRB 220711B: Swift-BAT refined analysis
  22. IPN triangulation of GRB 220711C (short)
  23. GRB 220711B: Swift-XRT refined Analysis
  24. GRB 220711B: Swift/UVOT Upper Limits
  25. GRB 220711B: Enhanced Swift-XRT position
  26. GRB 220711B: Fermi GBM Detection
  27. GRB 220711B: NOT optical observations
  28. GRB 220711B: LCO Optical Upper Limits
  29. GRB 220711B: Swift detection of a burst
  30. GRB 220711B: Fermi GBM Final Real-time Localization
  31. GRB 220707A: AstroSat CZTI detection
  32. GRB 220708B: GIT optical upper limits
  33. GRB 220711A: Fermi GBM Final Real-time Localization
  34. GRB 220708A: Swift-BAT refined analysis
  35. GRB 220708B: T193-OHP optical upper limit
  36. Konus-Wind detection of GRB 220708B (Correction to GCN 32358)
  37. Konus-Wind detection of GRB 220708B
  38. IceCube-220624A: Classification of AT2022nit as a type Ia supernova and AT2021bei as an AGN
  39. GRB 220708B: CALET Gamma-Ray Burst Monitor detection
  40. GRB 220708B: Nanshan/NEXT optical upper limits
  41. GRB 220708A: Swift/UVOT Upper Limits
  42. GRB 220706A : NICER detection of re-brightening 1 day after the Swift trigger
  43. GRB 220708A: Swift-XRT refined Analysis
  44. GRB 220706A: Swift/UVOT Upper Limits
  45. GRB 220708B: Swift-XRT afterglow detection
  46. GRB 220708A: BOOTES-5/JGT early optical upper limit
  47. GRB 220706A: Swift-BAT refined analysis
  48. GRB 220708A: Enhanced Swift-XRT position
  49. GRB 220708B: Swift ToO observations
  50. GRB 220708B: Swift/BAT-GUANO arcminute localization
  51. GRB 220708A: Swift-XRT observations
  52. GRB 220708A: Swift detection of a burst
  53. GRB 220706A: LCO Optical Upper Limits
  54. GRB 220627A: ATCA detection of radio counterpart
  55. GRB 220706A: Swift-XRT refined Analysis
  56. GRB 220706A, GROND observations
  57. GRB 220706A: Optical observations from NOT
  58. GRB 220706A: MAXI/GSC detection 84 minutes after the Swift Trigger
  59. GRB 220702B: AstroSat CZTI detection
  60. GRB 220706A: Nanshan/NEXT optical upper limits
  61. MAXI GRB220706.73: Global MASTER-Net observations report
  62. GRB 220706A: Enhanced Swift-XRT position
  63. Swift GRB 220706A: Global MASTER-Net observations report
  64. GRB 220706A: Zadko observatory - Gingin optical observations
  65. GRB 220706A: Prompt enhanced Swift-XRT position
  66. GRB 220706A: Swift detection of a burst
  67. GRB 220701A: Swift-BAT refined analysis
  68. GRB220408A: VIRT Optical Upper Limit
  69. GRB220412A: VIRT Optical Upper Limit
  70. GRB220701A: VIRT Optical Upper Limit
  71. GRB 220702B: Fermi GBM Final Localization
  72. GRB 220702A: Fermi GBM Final Localization
  73. GRB 220705A: Fermi GBM Final Localization
  74. Fermi trigger No 678635286: Global MASTER-Net observations report
  75. GRB 220701A: MITSuME Akeno optical upper limits
  76. Alert from the HAWC Burst Monitor HAWC-220702A
  77. GRB 220701A: COATLI Optical Upper Limit
  78. GRB 220701A: AbAO optical upper limit
  79. GRB 220627A: AstroSat CZTI detection
  80. GRB 220701A: Keck/LRIS Optical Upper Limit
  81. GRB 220701A: Swift-XRT refined Analysis
  82. GRB 220701A: LCO Optical Upper Limits
  83. IceCube-220629A: Upper limits from a search for additional neutrino events in IceCube
  84. GRB 220701A: BOOTES-5/JGT early optical upper limit
  85. GRB 220701A: Swift/UVOT Upper Limits
  86. GRB 220701A: Lowell Discovery Telescope Optical Observations
  87. GRB 220701A: Enhanced Swift-XRT position
  88. GRB 200701A: KAIT Optical Upper Limit
  89. GRB 220701A: Swift detection of a burst
  90. Fermi-LAT Gamma-ray Observations of IceCube-220629A
  91. GRB 220627A, GROND observations
  92. GRB 220624A: AGILE/GRID refined analysis
  93. GRB 220627A: Swift/UVOT Upper Limits
  94. Fermi-LAT Gamma-ray Observations of IceCube-220627A
  95. IceCube-220629A: No significant detection in HAWC
  96. IceCube-220629A - IceCube observation of a high-energy neutrino candidate track-like event
  97. IceCube-220627A: No significant detection in HAWC
  98. IceCube Alert 220629.99: Global MASTER-Net observations report
  99. GRB 220627A: Swift-XRT afterglow detection
  100. Konus-Wind detection of GRB 220627A

Advanced

Download all Circulars as a .tar.gz archive:
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