Skip to main content
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 091029: Swift-BAT refined analysis
  2. GRB 091029: Enhanced Swift-XRT position
  3. GRB091024 optical observations
  4. GRB 091029: Gemini-South Redshift
  5. GRB 091029: Skynet/PROMPT Observations of Peak and Fading
  6. GRB 091029: GROND Detection of the Optical/NIR Afterglow
  7. GRB 091029: Swift detection of a burst with an optical counterpart
  8. A mistake in testing a new function in Swift
  9. GRB 091020: Fermi GBM observation
  10. GRB 091026: Suzaku WAM observation of the prompt emission
  11. GRB 091024: Keck/LRIS Spectroscopy
  12. GRB 091024: YNAO-GMG observations
  13. GRB 091026: GROND Upper Limits
  14. GRB 091020: Late TLS detection
  15. GRB 091026: Swift-BAT refined analysis
  16. Radio afterglow detection from GRB 091020
  17. GRB 091026: Swift/UVOT Upper Limits
  18. GRB 091024: Burst was outside the Swift-BAT FOV after T0(BAT)+460sec
  19. GRB 091026: Swift-XRT refined analysis
  20. GRB 091026: Enhanced Swift-XRT position
  21. Konus-Wind and Konus-RF observations of GRB 091024
  22. GRB 091026: Updated Swift-XRT position
  23. GRB 091026: Swift detection of a Gamma Ray Burst
  24. GRB 091020 : Xinglong TNT upper limit
  25. Swift-BAT Triggers 373776-373778 are not real
  26. GRB091024 Swift/UVOT Upper Limits
  27. GRB 091024: TLS Upper Limit
  28. GRB 091020: Early TLS Multicolor detections, red afterglow
  29. GRB 091024: KAIT optical afterglow observations
  30. GRB 091024: Super-LOTIS early observations
  31. GRB091024: VRcIc Afterglow Observations
  32. GRB 091024: Swift-BAT refined analysis
  33. Swift-BAT Triggers 373679-373684 are not real
  34. GRB 091024: Fermi GBM Observations
  35. GRB 091024: Swift-XRT team refined analysis
  36. Swift-BAT trigger 373691 is a galactic bulge transient
  37. GRB 091024: Xinglong TNT optical observation
  38. GRB 091024 : Faulkes Telescope North - Afterglow Confirmation
  39. GRB 091024 Gemini-North redshift
  40. GRB 091024: GRAS004 optical observations
  41. GRB 091024: Faulkes Telescope North Afterglow Candidate
  42. GRB 091024: Swift detection of a burst
  43. GRB 091018: Skynet/PROMPT Continued Observations of Fading
  44. GRB 091020: Additional Lick observations
  45. Konus-Wind observations of GRB 091020 (correction to GCN 10057)
  46. GRB 091020: Lick observations
  47. Konus-Wind observations of GRB 091010
  48. GRB 091020: Swift-XRT refined analysis
  49. GRB 091018: Swift XRT refined analysis
  50. GRB091020 Swift/UVOT observations
  51. GRB 091020: NOT spectroscopic redshift
  52. GRB 091020: MASTER optical transient polarimetry
  53. GRB 091020, Swift-BAT refined analysis
  54. GRB 091020: Enhanced Swift-XRT position
  55. GRB 090926A: Late-time Gemini South Observations and Possible Jet Break
  56. GRB 091020: Swift detection of a burst with an optical afterglow
  57. GRB 091018: miniTAO/ANIR Observations
  58. GRB 091018: Skynet/PROMPT Observations of Fading
  59. Konus-RF observation of GRB 091018
  60. GRB 091018 : Faulkes Telescope South Observations
  61. GRB 091018: BOOTES-3 observations
  62. GRB 091018: VLT/X-shooter spectra
  63. GRB091018: Swift/UVOT observations
  64. GRB 091018: Swift-BAT refined analysis
  65. GRB 091018: GROND observations
  66. GRB091018: Magellan Echellette Observations
  67. GRB 091018: Enhanced Swift-XRT position
  68. GRB 091018: ROTSE-III Detection of Optical Counterpart
  69. GRB 091015: Skynet/PROMPT Observations
  70. GRB 091018: Swift detection of a burst with optical afterglow
  71. Fwd: GRB 091003: Possible Supernova Component Retraction
  72. GRB 091003: Possible Supernova Component
  73. GRB 091003: Gemini-N redshift of possible host galaxy
  74. GRB 091010: optical obsevation
  75. GRB 091015: RTT150 optical observations
  76. GRB 090726 R band observations
  77. GRB 091010: optical afterglow candidate rejection
  78. GRB 091015: correction to GCN 10025
  79. GRB 090815: a faint long GRB localized by INTEGRAL
  80. GRB 091010: Swift-XRT refined analysis
  81. GRB 091010: Suzaku WAM observation of the prompt emission
  82. GRB 091010: AGILE-MCAL measurement and GRID upper limit
  83. Radio observation of GRB090927 with ATCA
  84. Radio observation of GRB090926a with ATCA
  85. Radio observation of GRB080916c with ATCA
  86. GRB 091010: Fermi GBM observation
  87. GRB 091010: Faulkes Telescope North observations
  88. GRB 090531A: Skynet/PROMPT Observations
  89. GRB 090530A: Skynet/DSO Detections
  90. GRB 091010: RXTE detection
  91. Konus-Wind observations of GRB 091010
  92. GRB 091010: Enhanced XRT position
  93. GRB 091010 optical upper limits
  94. Detection of a short GRB 090929A by RT-2 Experiment
  95. RT-2 observation of the bright GRB 090926A
  96. GRB 091010: GROND afterglow candidate
  97. GRB 091010: Swift/UVOT Upper Limits
  98. GRB 091010: Swift-XRT position
  99. SuperAGILE GRB is 091010 and not 090910
  100. GRB 090910: SuperAGILE Localization of a Long GRB

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