Skip to main content
New! Browse Circulars by Event, Advanced Search, Sample Codes, Schema Release. 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"

18991 results found.

  1. GRB050922C: optical observations
  2. GRB 050922C: Absorption redshift from the Nordic Optical Telescope
  3. GRB 050922C: optical obserations
  4. GRB 050922C: NOT optical observations
  5. GRB 050922A: Analysis of Swift/XRT TOO observation
  6. GRB 050922C: Swift detection of a bright burst
  7. GRB 050922C: ROTSE-IIId Refined Analysis
  8. GRB 050922C: ROTSE-III Detection of Possible Counterpart
  9. GRB 050922B: ROTSE-III Optical Limits
  10. GRB 050922B,optical observation
  11. GRB050922B: Swift-BAT detection of a weak long burst
  12. GRB050918: Possible Swift/XRT detected afterglow
  13. GRB050820B: analysis of the XMM-Newton observation
  14. GRB050916: Swift/UVOT Upper Limits
  15. GRB 050916: Swift-BAT refined analysis
  16. Swift-BAT trigger 155764 is not a GRB
  17. Swift-BAT trigger 155764 is probably not a GRB
  18. Swift trigger 155764: bad XRT centroid
  19. Swift-BAT trigger 155535 is definitely not a GRB
  20. GRB050916 : Swift-XRT refined analysis
  21. GRB 050916: XRT position
  22. GRB 050915B: Swift-BAT refined analysis
  23. GRB 050915B: Swift/UVOT Upper Limits
  24. GRB050916: Swift-BAT detection of a long weak burst
  25. GRB 050915B: XRT position
  26. GRB050915B: Swift-BAT detection of a long bright burst
  27. GRB050915: Swift/UVOT upper limits
  28. GRB 050915: KAIT optical limit
  29. GRB 050915: IR Observations
  30. GRB 050915: Swift XRT refined analysis
  31. GRB 050915: Swift-BAT refined analysis
  32. GRB050915, optical observations
  33. GRB050915: XRT position
  34. GRB 050915: ROTSE-III optical limits
  35. GRB 050915: Swift detection of a GRB
  36. GRB050911: Upper limit on X-ray afterglow
  37. Swift-BAT trigger 155072 ground analysis
  38. Swift-BAT trigger 155072 is probably not a GRB
  39. GRB050914: XRT position probably due to cosmic ray
  40. Swift is in normal operation
  41. GRB050911: Swift UVOT followup observations
  42. GRB 050911, optical content of Swift/XRT error box
  43. GRB050911: Swift-XRT position
  44. GRB 050911, optical observations
  45. GRB 050911: Swift-BAT refined analysis
  46. Later Swift-BAT triggers 154632 and 154633 RETRACTION
  47. GRB050911: Swift-BAT detection of a long burst
  48. GRB050908: detection of Swift/UVOT optical counterpart
  49. RBO GRB 050908 observations
  50. WIRO observations in I of GRB 050908
  51. GRB 050906: Possible X-ray Counterpart
  52. GRB050908: Swift/UVOT Early upper limits
  53. GRB050908 : Swift-XRT refined analysis
  54. GRB 050908: Swift-BAT refined analysis
  55. GRB 050908: Optical observations
  56. Gemini Spectroscopy of GRB 050908
  57. GRB 050908 : Swift XRT position
  58. GRB 050908: KAIT observations
  59. GRB 050908: P60 Confirmation of Optical Afterglow
  60. GRB 050908: Swift detection of a burst
  61. Swift trigger 154073 is not a GRB
  62. GRB050904: CrAO optical observations
  63. GRB 050904 BAT refined analysis of complete data set
  64. GRB 050906: MARGE Optical Limits
  65. GRB 050906: Swift-BAT refined analysis
  66. GRB 050906: Swift XRT upper limit
  67. GRB050906: P60 Observations
  68. GRB 050904: Did SWIFT/XRT see the prompt GRB emission ?
  69. GRB 050906: Bright galaxy in BAT error box
  70. GRB 050906: Swift/BAT Detection of a possible burst
  71. GRB 050904: Swift/UVOT observations
  72. GRB 050904: early Swift XRT analysis results
  73. GRB 050904: BAT refined analysis of partial data set
  74. GRB050904: P60 Observations
  75. GRB 050904: TAROT optical limits
  76. GRB050904: Swift-BAT detection of a probable burst
  77. Swift-BAT triggers 153461-153465 are not GRBs
  78. Retraction of Swift-BAT trigger #153355
  79. GRB 050824: MDM Observations
  80. GRB 050827: Swift XRT preliminary analysis results
  81. Swift Trigger #152652 is not a GRB
  82. GRB050827: Swift/UVOT upper limits
  83. GRB 050827: Optical Limit
  84. GRB 050827: XRT possible afterglow detection
  85. GRB050827: RTT150 optical observations
  86. GRB 050827: Swift-BAT refined analysis
  87. GRB050827: Swift-BAT detection of a burst
  88. GRB 050826: Optical Candidate
  89. GRB050824, HETE-2 Observation
  90. GRB 050826: Swift XRT preliminary analysis results
  91. GRB 050826: BAT refined analysis
  92. GRB050826: Swift/UVOT early upper limits
  93. GRB050824: First 2 hours of power low optical decay?
  94. GRB 050826: Swift XRT position
  95. GRB050826: Swift-BAT detection of a long burst
  96. GRB050824: MASTER final analysis of the OT observations
  97. Possible GRB050825:MASTER optical observations
  98. Swift-BAT trigger 152038 is definitely not a GRB
  99. GRB050824: CORRECTION to UVOT observing times
  100. Swift-BAT trigger 152038 is probably not a GRB

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