Skip to main content
Passing of Scott Barthelmy, GCN Founder 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 071008, Swift-BAT refined analysis
  2. GRB 071010, Swift-BAT refined analysis
  3. Konus-Wind observation of GRB 071006
  4. GRB071008: Swift-XRT observation
  5. GRB 071010 REM NIR observations
  6. GRB 071010: Keck/LRIS Spectroscopy
  7. GRB 071010: TAROT La Silla observatory photometry of the afterglow
  8. GRB 071010: Rapid PROMPT Detections
  9. GRB 071010: Keck Observations of the Afterglow
  10. GRB 071010: TAROT La Silla observatory detection of the afterglow
  11. GRB 071010: Swift detection of a burst
  12. GRB 071006 Swift-BAT detection of a burst
  13. GRB071008: IAC80 observation
  14. GRB 071008: Swift detection of a burst
  15. GRB 071003: XRT refined analysis
  16. GRB070920A: MAGIC telescope GeV observation
  17. Radio detection of GRB 071003 with the VLA
  18. GRB 070810B: further XRT analysis
  19. GRB 071003: VLT spectroscopy
  20. GRB 071003: Keck spectroscopy
  21. Konus-Wind observation of GRB 071003
  22. GRB071003: Faulkes Telescope North observations
  23. GRB 071003: Possible rebrightening
  24. GRB 071003 : Lulin R-band observations
  25. GRB 071003: Swift XRT position
  26. GRB 071003: OA power-law decay indices from KAIT
  27. GRB 071003: Keck HIRES spectroscopy
  28. GRB 071003, Swift-BAT refined analysis
  29. GRB 071003: MARGE Observations
  30. GRB 071003 Optical observations
  31. GRB 071003: P60 Confirmation of Optical Afterglow
  32. GRB 071003: KAIT optical afterglow observations
  33. GRB 071003: Swift detection of a bright burst
  34. GRB 070714B: host galaxy spectroscopic redshift
  35. GRB 071001: Swift-XRT Team refined analysis
  36. GRB 071001, Swift-BAT refined analysis
  37. Faulkes Telescope South observations of GRB 071001
  38. GRB 071001: Swift detection of a burst
  39. VLA observation of GRB 070923
  40. Disregard the Swift-XRT Notices today
  41. GRB 070911, SMARTS optical/IR afterglow observations
  42. GRB070925: Swift-XRT Afterglow confirmation
  43. GRB 070925: Gemini South Imaging
  44. GRB070925: Swift-XRT Position
  45. Update on Swift Status
  46. GRB 070920B: ROTSE-III Early Optical Limits
  47. GRB 070925: a long GRB detected by INTEGRAL
  48. Recent SGR1806-20 Activity
  49. GRB 070923, Swift-BAT refined analysis
  50. GRB 070920B: XRT observations
  51. GRB 070923: Galaxies within BAT localization
  52. GRB 070923: Swift detection of a short hard burst
  53. GRB 070917: Suzaku/WAM observation of the prompt emission
  54. GRB 070920B: TAROT La Silla observatory optical observations
  55. INTEGRAL ToO observations of SGR1806-20
  56. GRB 070920b, SMARTS optical observation
  57. GRB 070917: Confirmation of the X-ray afterglow
  58. GRB 070920b: LCO optical observations
  59. GRB 070920B, Swift-BAT refined analysis
  60. GRB 070911: Swift/BAT and Suzaku/WAM joint spectral analysis
  61. GRB 070920B: NOT optical observations
  62. GRB 070920B: Swift detection of a burst
  63. GRB 070920, Swift-BAT refined analysis
  64. GRB 070920: TAROT Calern observatory optical observations
  65. GRB 070920: Swift detection of a burst
  66. SGR1806-20: Swift-BAT detection of enhanced activity
  67. GRB070917: Confirmation of optical afterglow
  68. GRB920925C: search for host galaxy
  69. GRB070917: optical observations
  70. GRB 070917: P60 Observations
  71. GRB 070917: pseudo-z= 2.40 from prompt emission spectrum
  72. Konus-Wind observation of GRB 070917
  73. Swift Status and XRT Calibration Uncertainties
  74. GRB 070917: Swift-XRT observations
  75. GRB 070917: KAIT optical limits
  76. GRB 070917: MITSuME Akeno Ic upper limit
  77. GRB 070917: R band observations
  78. GRB 070917, Swift-BAT refined analysis
  79. GRB 070917: Swift detection of a bright burst
  80. GRB 070911: Suzaku WAM observation of the prompt emission
  81. GRB 070913: Swift-XRT detection of the possible X-ray afterglow
  82. GRB 070809: The Swift evidence for the SHB nature of this burst
  83. GRB 070913: Afterglow candidate detected by TAROT La Silla observatory
  84. GRB 070913: Swift-BAT refined analysis
  85. GRB 070913: Corrected BAT position
  86. GRB 070913: SMARTS optical/IR observations
  87. GRB 070913: TAROT La Silla observatory optical observations
  88. GRB 070913: Swift detection of a burst
  89. Swift-BAT Notices back to autonomous real-time distribution
  90. GRB 070911: PAIRITEL IR Observations
  91. GRB 070911: Swift XRT refined analysis
  92. GRB 070911, Swift-BAT refined analysis
  93. GRB 070911: Swift detection of a burst
  94. IPN search for a GRB associated with TAROT transient on August 31
  95. Intense burst from SGR 1806-20 detected on September 7
  96. GRB 070809: Confirmation of optical transient
  97. Observations of possible TAROT GRB transient near IC 4779
  98. Candidate Orphan GRB Optical Transient in IC 4779
  99. GRB 070810b: Image Subtraction of Multiple Keck Observations
  100. Las Campanas observations of possible TAROT GRB transient near IC

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