Skip to main content
Retirement of GCN Classic VOEvent Brokers. 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. VLA non-detection of GRB 071011
  2. GRB 071013: Optical observations
  3. GRB 071013: optical observations at NOT
  4. GRB 071013, Swift-BAT refined analysis
  5. GRB071013: optical limit
  6. GRB071010B, BVRcIc field calibration
  7. GRB 20071013: Xinglong TNT optical Upper Limit
  8. GRB 071013: Swift detection of a burst
  9. GRB 071010C Swift-BAT detection of a burst
  10. GRB 071011: Optical Limit after 13.95hrs
  11. GRB 071011: Xinglong TNT Optical afterglow observations
  12. GRB 071010B correction to GCN 6892 optical observations
  13. GRB 071011: Swift-XRT refined analysis
  14. VLA non-detection of GRB 071010A
  15. GRB 071011: NAYUTA Optical Observation, correction to GCN6886
  16. GRB 071011, Optical afterglow
  17. GRB 071011: Confirmation of P60 optical afterglow
  18. GRB 071010B: Optical Detection
  19. GRB 071011: Kanazawa Optical limits
  20. GRB 071011: P60 Optical Afterglow Candidate
  21. GRB 071011: MARGE Optical Limits
  22. GRB 071010B: Super-LOTIS upper limit
  23. GRB 071010B optical photometry
  24. GRB 071011: XRT afterglow detection
  25. GRB 071010B: Keck/LRIS Spectroscopy
  26. GRB 071011, Swift-BAT refined analysis
  27. GRB 071010B: Gemini Spectroscopic Observations
  28. GRB 071011: Early Super-LOTIS Observations
  29. GRB 071011: NAYUTA Optical Observation
  30. GRB 071010A: Continued Keck Imaging
  31. GRB 071010B: Bright OT confirmed with TLS
  32. GRB 071011: Optical afterglow candidate
  33. GRB 071011: Swift detection of a burst
  34. Optical Observation: GRB 071010
  35. Optical observations: GRB 071010A
  36. Konus-Wind observation of GRB 071010B
  37. GRB071010B: Swift/XRT detection
  38. GRB 071010B, Swift-BAT refined analysis
  39. GRB 071010A: bright NIR afterglow
  40. GRB 071006, Swift-BAT refined analysis
  41. GRB071008: optical observations
  42. GRB 071010B possible optical transient
  43. GRB 071010A: Keck/LRIS Photometry
  44. GRB 071010B: Swift detection of a burst
  45. GRB 071010: Swift-XRT observation
  46. GRB 071008, Swift-BAT refined analysis
  47. GRB 071010, Swift-BAT refined analysis
  48. Konus-Wind observation of GRB 071006
  49. GRB071008: Swift-XRT observation
  50. GRB 071010 REM NIR observations
  51. GRB 071010: Keck/LRIS Spectroscopy
  52. GRB 071010: TAROT La Silla observatory photometry of the afterglow
  53. GRB 071010: Rapid PROMPT Detections
  54. GRB 071010: Keck Observations of the Afterglow
  55. GRB 071010: TAROT La Silla observatory detection of the afterglow
  56. GRB 071010: Swift detection of a burst
  57. GRB 071006 Swift-BAT detection of a burst
  58. GRB071008: IAC80 observation
  59. GRB 071008: Swift detection of a burst
  60. GRB 071003: XRT refined analysis
  61. GRB070920A: MAGIC telescope GeV observation
  62. Radio detection of GRB 071003 with the VLA
  63. GRB 070810B: further XRT analysis
  64. GRB 071003: VLT spectroscopy
  65. GRB 071003: Keck spectroscopy
  66. Konus-Wind observation of GRB 071003
  67. GRB071003: Faulkes Telescope North observations
  68. GRB 071003: Possible rebrightening
  69. GRB 071003 : Lulin R-band observations
  70. GRB 071003: Swift XRT position
  71. GRB 071003: OA power-law decay indices from KAIT
  72. GRB 071003: Keck HIRES spectroscopy
  73. GRB 071003, Swift-BAT refined analysis
  74. GRB 071003: MARGE Observations
  75. GRB 071003 Optical observations
  76. GRB 071003: P60 Confirmation of Optical Afterglow
  77. GRB 071003: KAIT optical afterglow observations
  78. GRB 071003: Swift detection of a bright burst
  79. GRB 070714B: host galaxy spectroscopic redshift
  80. GRB 071001: Swift-XRT Team refined analysis
  81. GRB 071001, Swift-BAT refined analysis
  82. Faulkes Telescope South observations of GRB 071001
  83. GRB 071001: Swift detection of a burst
  84. VLA observation of GRB 070923
  85. Disregard the Swift-XRT Notices today
  86. GRB 070911, SMARTS optical/IR afterglow observations
  87. GRB070925: Swift-XRT Afterglow confirmation
  88. GRB 070925: Gemini South Imaging
  89. GRB070925: Swift-XRT Position
  90. Update on Swift Status
  91. GRB 070920B: ROTSE-III Early Optical Limits
  92. GRB 070925: a long GRB detected by INTEGRAL
  93. Recent SGR1806-20 Activity
  94. GRB 070923, Swift-BAT refined analysis
  95. GRB 070920B: XRT observations
  96. GRB 070923: Galaxies within BAT localization
  97. GRB 070923: Swift detection of a short hard burst
  98. GRB 070917: Suzaku/WAM observation of the prompt emission
  99. GRB 070920B: TAROT La Silla observatory optical observations
  100. INTEGRAL ToO observations of SGR1806-20

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