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. Renewal of SGR 1806-20 activity
  2. GRB 050502a: RBO Observations
  3. GRB 050502A: WSRT Radio Observations
  4. GRB050502A: Optical Observations
  5. GRB050502B Swift-BAT refined analysis
  6. GRB050502B: I band source in XRT error circle
  7. Swift UVOT refined analysis
  8. Retraction of Swift-BAT trigger 116145
  9. GRB 050502a : R band observation at Lulin observatory
  10. GRB 050502b : optical observation at Lulin observatory
  11. GRB 050502b: Swift XRT Position
  12. GRB 050502A: Redshift measurement based on Keck HIRES Observations
  13. GRB050502B: Optical Limits from ANU 1m
  14. Swift Detection of the Bright Burst GRB050502b
  15. GRB 050502: INTEGRAL results
  16. GRB050502: ANU 1m optical Observations
  17. GRB 050502: Confirmed variability of the afterglow candidate +
  18. GRB 050502: PAIRITEL IR Observations
  19. GRB050502 - Correction on the Optical Candidate from the Liverpool
  20. GRB050502 - Optical Candidate from the Liverpool Telescope
  21. GRB 050502 - A long GRB detected with INTEGRAL
  22. GRB 050502: ROTSE-III Detection of Possible Counterpart
  23. Swift-BAT Trigger 115881 is not a real GRB
  24. Swift/BAT possible detection of a weak burst GRB050430
  25. GRB 050401: Rc observation
  26. GRB050416a: Radio Detection
  27. GRB 050422: Swift-UVOT observation
  28. GRB 050422: Swift-BAT refined analysis
  29. GRB 050422: Swift XRT Position
  30. Swift Detection of GRB 050422
  31. GRB 050421: NIR observations
  32. GRB 050416: Optical/NIR observations
  33. GRB 050421: SLOTIS observations
  34. GRB 050421: Further Analysis of IR imaging
  35. GRB050421: Radio Observations
  36. GRB050421: Radio Observations
  37. GRB 050421: Swift-UVOT observation
  38. GRB 050421: IR Observations
  39. GRB 050421: Swift-BAT refined analysis
  40. GRB 050421: ROTSE-III Optical Limits
  41. GRB 050421: NIR observations re-examination
  42. GRB050421
  43. GRB 050421: early Swift XRT analysis results
  44. GRB 050421: NIR observations
  45. GRB050421: P60 Observations
  46. GRB 050421: BOOTES-2 simultaneous optical observations
  47. GRB 050421: Optical observations at the INT
  48. Swift Detection of GRB050421
  49. GRB 050416b: Tentative Swift XRT Position
  50. GRB 050315: potential host galaxy
  51. GRB050326: analysis of the XMM-Newton observation
  52. GRB050418: Null Optical Observations
  53. GRB 050412: Chandra observations
  54. GRB050416A, optical observations
  55. GRB 050418: Swift-BAT refined analysis
  56. Swift-BAT detection of the bright and long GRB 050418
  57. GRB 050416: Mitsume optical observation
  58. GRB 050416 : optical observation at Xinglong observatory
  59. GRB 050416B: optical observations
  60. GRB 050416b: Swift-BAT refined analysis
  61. GRB 050416b: LCO observations
  62. GRB 050416b: LCO observations
  63. GRB050416B: IR observations
  64. GRB 050416: Swift/UVOT refined analysis
  65. Swift-BAT detection of GRB 050416b
  66. IBAS GRB Alert # 2463: not a GRB
  67. GRB050412: Radio Observations
  68. GRB 050416: Swift/UVOT detection of afterglow emission
  69. GRB050416: Refined Swift-XRT analysis
  70. GRB050416: Maidanak optical observations
  71. GRB 050416: Swift-BAT refined analysis
  72. GRB 050416: ART observations
  73. GRB 050416,optical observation
  74. GRB 050416: KAIT observations
  75. GRB050416: P200 NIR Observations
  76. GRB 050416: Swift XRT Position
  77. GRB 050416: Radio observations
  78. Confirmation of OT for GRB050416
  79. GRB050416: P60 Afterglow Candidate
  80. Swift BAT/XRT Detection of GRB 050416
  81. GRB 050412: Subaru observations
  82. GRB 050408: RTT150 optical observations
  83. GRB050408: optical observation
  84. GRB 050412: PROMPT VRcIc Observations
  85. GRB 050408: Kuiper 1.5m observations
  86. GRB 050412: optical limit
  87. GRB 050412: optical observations
  88. GRB 050408: refined XRT analysis, no jet break seen yet
  89. GRB 050412: early Swift XRT analysis results
  90. GRB 050412 : XingLong optical observation
  91. GRB 050412: Swift-BAT refined analysis
  92. GRB 050412: ANU 2.3m observations
  93. GRB 050412: Early Optical/Ultraviolet Observations with
  94. GRB 050412: retraction of UVOT transient report
  95. GRB 050412: UVOT transient not in XRT error circle
  96. GRB 050408: SDSS Field Calibration
  97. GRB 050412: Optical limit
  98. GRB 050412: LCO Optical Observations
  99. GRB 050412: Optical observations
  100. GRB050412: P60 Observations

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