Skip to main content
Testing. You are viewing the public testing version of GCN. For the production version, go to https://gcn.nasa.gov.
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. GRB050421
  2. GRB 050421: early Swift XRT analysis results
  3. GRB 050421: NIR observations
  4. GRB050421: P60 Observations
  5. GRB 050421: BOOTES-2 simultaneous optical observations
  6. GRB 050421: Optical observations at the INT
  7. Swift Detection of GRB050421
  8. GRB 050416b: Tentative Swift XRT Position
  9. GRB 050315: potential host galaxy
  10. GRB050326: analysis of the XMM-Newton observation
  11. GRB050418: Null Optical Observations
  12. GRB 050412: Chandra observations
  13. GRB050416A, optical observations
  14. GRB 050418: Swift-BAT refined analysis
  15. Swift-BAT detection of the bright and long GRB 050418
  16. GRB 050416: Mitsume optical observation
  17. GRB 050416 : optical observation at Xinglong observatory
  18. GRB 050416B: optical observations
  19. GRB 050416b: Swift-BAT refined analysis
  20. GRB 050416b: LCO observations
  21. GRB 050416b: LCO observations
  22. GRB050416B: IR observations
  23. GRB 050416: Swift/UVOT refined analysis
  24. Swift-BAT detection of GRB 050416b
  25. IBAS GRB Alert # 2463: not a GRB
  26. GRB050412: Radio Observations
  27. GRB 050416: Swift/UVOT detection of afterglow emission
  28. GRB050416: Refined Swift-XRT analysis
  29. GRB050416: Maidanak optical observations
  30. GRB 050416: Swift-BAT refined analysis
  31. GRB 050416: ART observations
  32. GRB 050416,optical observation
  33. GRB 050416: KAIT observations
  34. GRB050416: P200 NIR Observations
  35. GRB 050416: Swift XRT Position
  36. GRB 050416: Radio observations
  37. Confirmation of OT for GRB050416
  38. GRB050416: P60 Afterglow Candidate
  39. Swift BAT/XRT Detection of GRB 050416
  40. GRB 050412: Subaru observations
  41. GRB 050408: RTT150 optical observations
  42. GRB050408: optical observation
  43. GRB 050412: PROMPT VRcIc Observations
  44. GRB 050408: Kuiper 1.5m observations
  45. GRB 050412: optical limit
  46. GRB 050412: optical observations
  47. GRB 050408: refined XRT analysis, no jet break seen yet
  48. GRB 050412: early Swift XRT analysis results
  49. GRB 050412 : XingLong optical observation
  50. GRB 050412: Swift-BAT refined analysis
  51. GRB 050412: ANU 2.3m observations
  52. GRB 050412: Early Optical/Ultraviolet Observations with
  53. GRB 050412: retraction of UVOT transient report
  54. GRB 050412: UVOT transient not in XRT error circle
  55. GRB 050408: SDSS Field Calibration
  56. GRB 050412: Optical limit
  57. GRB 050412: LCO Optical Observations
  58. GRB 050412: Optical observations
  59. GRB050412: P60 Observations
  60. GRB 050412: Swift XRT Position
  61. GRB050412: optical limit before and during GRB
  62. GRB 050412: LCO optical observations
  63. GRB050412: ROTSE-III Optical Limits
  64. Swift-BAT Detection of GRB 050412: A Bright, Long Burst
  65. GRB 050412: IR and Optical observations
  66. GRB 050412: IR Observations
  67. GRB050408: Radio Observations
  68. GRB 050401: Optical limit
  69. GRB 050408: Optical limit
  70. GRB050410: P60 Observations
  71. GRB 050410: Early Optical/Ultraviolet Observations with Swift/UVOT
  72. GRB 050410, optical observations
  73. GRB 050408: PROMPT VRcIc Observations
  74. GRB 050408: Early Optical/Ultraviolet Observations with Swift/UVOT
  75. GRB 050410 R band Optical Observations
  76. GRB050410 : Null detection report
  77. GRB 050410, optical observations
  78. GRB050410: Radio Observations
  79. GRB 050408: Swift XRT measurement of possible jet break
  80. GRB050410: MASTER optical observations
  81. GRB 050410: Early observations with Swift-UVOT
  82. Swift-BAT detection of GRB 050410
  83. GRB 050410: Swift XRT Position
  84. GRB 050408: Retraction of Proposed Host Galaxy
  85. GRB 050408: Inconsistency of host galaxy identification
  86. GRB 050408: Subaru Observations
  87. GRB 050408: WIDGET simultaneous optical observations
  88. GRB 050408: SOAR UBVRc Observations
  89. GRB 050408: Properties of the Host Galaxy
  90. GRB 050408: Mercator Optical Observations
  91. GRB050408: Radio Observations
  92. GRB 050408: Swift XRT analysis
  93. GRB 050408, SMARTS optical/IR afterglow observations
  94. GRB 050408: Optical limit at 20 min after the burst
  95. GRB 050408, optical observations
  96. GRB050408: REM NIR and Optical observation
  97. GRB 050408: Moderate-resolution Gemini Spectroscopy
  98. GRB 050408,optical observation
  99. GRB 050408 Optical Observations
  100. GRB 050408: Emission and absorption redshift

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