Skip to main content
Due to the lapse in federal government funding, NASA is not updating this website. See the Operations FAQ for GCN impacts.
New! Super-Kamiokande JSON Notices and Schema v4.5.0. 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"

33670 results found.

  1. GRB 050422: Swift-UVOT observation
  2. GRB 050422: Swift-BAT refined analysis
  3. GRB 050422: Swift XRT Position
  4. Swift Detection of GRB 050422
  5. GRB 050421: NIR observations
  6. GRB 050416: Optical/NIR observations
  7. GRB 050421: SLOTIS observations
  8. GRB 050421: Further Analysis of IR imaging
  9. GRB050421: Radio Observations
  10. GRB050421: Radio Observations
  11. GRB 050421: Swift-UVOT observation
  12. GRB 050421: IR Observations
  13. GRB 050421: Swift-BAT refined analysis
  14. GRB 050421: ROTSE-III Optical Limits
  15. GRB 050421: NIR observations re-examination
  16. GRB 050421: early Swift XRT analysis results
  17. GRB 050421: NIR observations
  18. GRB050421: P60 Observations
  19. GRB 050421: BOOTES-2 simultaneous optical observations
  20. GRB 050421: Optical observations at the INT
  21. GRB 050416b: Tentative Swift XRT Position
  22. GRB 050315: potential host galaxy
  23. GRB 050412: Chandra observations
  24. GRB050416A, optical observations
  25. GRB 050418: Swift-BAT refined analysis
  26. Swift-BAT detection of the bright and long GRB 050418
  27. GRB 050416: Mitsume optical observation
  28. GRB 050416 : optical observation at Xinglong observatory
  29. GRB 050416B: optical observations
  30. GRB 050416b: Swift-BAT refined analysis
  31. GRB 050416b: LCO observations
  32. GRB 050416b: LCO observations
  33. GRB050416B: IR observations
  34. GRB 050416: Swift/UVOT refined analysis
  35. Swift-BAT detection of GRB 050416b
  36. IBAS GRB Alert # 2463: not a GRB
  37. GRB050412: Radio Observations
  38. GRB 050416: Swift/UVOT detection of afterglow emission
  39. GRB 050416: Swift-BAT refined analysis
  40. GRB 050416: ART observations
  41. GRB 050416,optical observation
  42. GRB 050416: KAIT observations
  43. GRB050416: P200 NIR Observations
  44. GRB 050416: Swift XRT Position
  45. GRB 050416: Radio observations
  46. Confirmation of OT for GRB050416
  47. GRB050416: P60 Afterglow Candidate
  48. Swift BAT/XRT Detection of GRB 050416
  49. GRB 050412: Subaru observations
  50. GRB 050408: RTT150 optical observations
  51. GRB 050412: PROMPT VRcIc Observations
  52. GRB 050408: Kuiper 1.5m observations
  53. GRB 050412: optical limit
  54. GRB 050412: optical observations
  55. GRB 050408: refined XRT analysis, no jet break seen yet
  56. GRB 050412: early Swift XRT analysis results
  57. GRB 050412 : XingLong optical observation
  58. GRB 050412: Swift-BAT refined analysis
  59. GRB 050412: ANU 2.3m observations
  60. GRB 050412: Early Optical/Ultraviolet Observations with
  61. GRB 050412: retraction of UVOT transient report
  62. GRB 050412: UVOT transient not in XRT error circle
  63. GRB 050408: SDSS Field Calibration
  64. GRB 050412: Optical limit
  65. GRB 050412: LCO Optical Observations
  66. GRB 050412: Optical observations
  67. GRB050412: P60 Observations
  68. GRB 050412: Swift XRT Position
  69. GRB050412: optical limit before and during GRB
  70. GRB 050412: LCO optical observations
  71. Swift-BAT Detection of GRB 050412: A Bright, Long Burst
  72. GRB 050412: IR and Optical observations
  73. GRB 050412: IR Observations
  74. GRB050408: Radio Observations
  75. GRB 050401: Optical limit
  76. GRB 050408: Optical limit
  77. GRB050410: P60 Observations
  78. GRB 050410: Early Optical/Ultraviolet Observations with Swift/UVOT
  79. GRB 050410, optical observations
  80. GRB 050408: PROMPT VRcIc Observations
  81. GRB 050408: Early Optical/Ultraviolet Observations with Swift/UVOT
  82. GRB 050410 R band Optical Observations
  83. GRB050410 : Null detection report
  84. GRB 050410, optical observations
  85. GRB050410: Radio Observations
  86. GRB 050408: Swift XRT measurement of possible jet break
  87. GRB050410: MASTER optical observations
  88. GRB 050410: Early observations with Swift-UVOT
  89. Swift-BAT detection of GRB 050410
  90. GRB 050410: Swift XRT Position
  91. GRB 050408: Retraction of Proposed Host Galaxy
  92. GRB 050408: Inconsistency of host galaxy identification
  93. GRB 050408: Subaru Observations
  94. GRB 050408: WIDGET simultaneous optical observations
  95. GRB 050408: SOAR UBVRc Observations
  96. GRB 050408: Properties of the Host Galaxy
  97. GRB 050408: Mercator Optical Observations
  98. GRB050408: Radio Observations
  99. GRB 050408: Swift XRT analysis
  100. GRB 050408, SMARTS optical/IR afterglow observations

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