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"
  1. GRB 220730A: Swift-XRT afterglow detection
  2. GRB 220730A: Swift/UVOT Upper Limits
  3. GRB 220730A: Swift-XRT observations
  4. GRB 220729A: AstroSat CZTI detection
  5. Swift GRB 220730A: Global MASTER-Net observations report
  6. GRB 220730A: Swift detection of a short hard burst
  7. Fermi trigger No 680782656: Global MASTER-Net observations report
  8. Fermi GRB 220728A: Global MASTER-Net observations report
  9. AMON Coincidence Alert from the sub-threshold IceCube-HAWC search NuEm-220728A
  10. GRB 220728A: Fermi GBM Final Real-time Localization
  11. GRB 220726A: Fermi GBM Final Real-time Localization
  12. Fermi trigger No 680421061: Global MASTER-Net observations report
  13. Fermi GRB 220724A: Global MASTER-Net observations report
  14. GRB 220724A: Fermi GBM Final Real-time Localization
  15. GRB 220715B: VIRT Optical Upper Limit
  16. Fermi GRB 220721A: Global MASTER-Net observations report
  17. GRB 220721A: Fermi GBM Final Real-time Localization
  18. Introducing new GCN Kafka broker and web site for transient alerts, https://gcn.nasa.gov
  19. Retraction: Fermi GBM trigger 679932336.585264/220719587 is not a GRB
  20. GRB 220715A: CALET Gamma-Ray Burst Monitor detection
  21. GRB 220711B: CALET Gamma-Ray Burst Monitor detection
  22. GRB 220719A: Fermi GBM Final Real-time Localization
  23. GRB 220715B: Swift-BAT refined analysis
  24. GRB220714B: UVOT detections
  25. GRB 220715B: Fermi GBM detection
  26. GRB 220715B: Swift-XRT refined Analysis
  27. GRB 220715B: Swift/UVOT Upper Limits
  28. GRB 220715B: Enhanced Swift-XRT position
  29. GRB 220715B: BOOTES-network optical upper limits
  30. Swift GRB 220715B: Global MASTER-Net observations report
  31. GRB 220715B: Prompt enhanced Swift-XRT position
  32. GRB 220715B: Swift detection of a burst
  33. GRB 220715B: Fermi GBM Final Real-time Localization
  34. GRB 220714B: Swift-BAT refined analysis
  35. GRB 220714B: Fermi GBM observation
  36. GRB 220715A: AGILE/MCAL detection
  37. GRB 220714B: LCO Optical Observations
  38. GRB 220715A: Fermi GBM Final Real-time Localization
  39. GRB 220714B: Swift-XRT refined Analysis
  40. Swift/BAT Trigger 1116172 (=GRB 220714A) is not a real astrophysical event
  41. GRB 220714B: UVOT afterglow discovery
  42. GRB 220714B: Enhanced Swift-XRT position
  43. GRB 220713A: Fermi GBM Final Localization
  44. GRB 220714B: Swift detection of a burst
  45. GRB 220714B: Fermi GBM Final Real-time Localization
  46. GRB 220714A: Possible Swift detection of a burst
  47. GRB 220710A: Swift/UVOT Upper Limits
  48. GRB 220711C: Fermi GBM Observation
  49. Retraction of GRB 220711B: 10.4 m GTC(+EMIR) observations (GCN 32387)
  50. GRB 220711B: 10.4 m GTC(+EMIR) observations
  51. GRB 220711B: 10.4 m GTC(+EMIR) observations
  52. GRB 220710A: Swift-XRT afterglow detection
  53. GRB 220711C: Swift/BAT-GUANO detection outside the coded FOV
  54. GRB 220711B, GROND observations
  55. Konus-Wind detection of GRB 220711C
  56. GRB 220711B: NUTTelA-TAO / BSTI Early Optical Limits (Preliminary)
  57. GRB 220711B: GIT optical upper limits
  58. Fermi trigger No 679248723: Global MASTER-Net observations report
  59. Fermi GRB 220711B: Global MASTER-Net observations report
  60. GRB 220712B: NOT optical afterglow confirmation
  61. GRB 220710A: Swift ToO observations
  62. GRB 220710A: Swift/BAT-GUANO arcminute localization
  63. GRB 220711B: Swift-BAT refined analysis
  64. IPN triangulation of GRB 220711C (short)
  65. GRB 220711B: Swift-XRT refined Analysis
  66. GRB 220711B: Swift/UVOT Upper Limits
  67. GRB 220711B: Enhanced Swift-XRT position
  68. GRB 220711B: Fermi GBM Detection
  69. GRB 220711B: NOT optical observations
  70. GRB 220711B: LCO Optical Upper Limits
  71. GRB 220711B: Swift detection of a burst
  72. GRB 220711B: Fermi GBM Final Real-time Localization
  73. GRB 220707A: AstroSat CZTI detection
  74. GRB 220708B: GIT optical upper limits
  75. GRB 220711A: Fermi GBM Final Real-time Localization
  76. GRB 220708A: Swift-BAT refined analysis
  77. GRB 220708B: T193-OHP optical upper limit
  78. Konus-Wind detection of GRB 220708B (Correction to GCN 32358)
  79. Konus-Wind detection of GRB 220708B
  80. IceCube-220624A: Classification of AT2022nit as a type Ia supernova and AT2021bei as an AGN
  81. GRB 220708B: CALET Gamma-Ray Burst Monitor detection
  82. GRB 220708B: Nanshan/NEXT optical upper limits
  83. GRB 220708A: Swift/UVOT Upper Limits
  84. GRB 220706A : NICER detection of re-brightening 1 day after the Swift trigger
  85. GRB 220708A: Swift-XRT refined Analysis
  86. GRB 220706A: Swift/UVOT Upper Limits
  87. GRB 220708B: Swift-XRT afterglow detection
  88. GRB 220708A: BOOTES-5/JGT early optical upper limit
  89. GRB 220706A: Swift-BAT refined analysis
  90. GRB 220708A: Enhanced Swift-XRT position
  91. GRB 220708B: Swift ToO observations
  92. GRB 220708B: Swift/BAT-GUANO arcminute localization
  93. GRB 220708A: Swift-XRT observations
  94. GRB 220708A: Swift detection of a burst
  95. GRB 220706A: LCO Optical Upper Limits
  96. GRB 220627A: ATCA detection of radio counterpart
  97. GRB 220706A: Swift-XRT refined Analysis
  98. GRB 220706A, GROND observations
  99. GRB 220706A: Optical observations from NOT
  100. GRB 220706A: MAXI/GSC detection 84 minutes after the Swift Trigger

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