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"

18476 results found.

  1. GRB 050925: WSRT Radio Observations
  2. GRB050925: Swift UVOT upper limits
  3. Refined analysis of the Swift-BAT soft short burst
  4. GRB050925: Faulkes Telescope North R-band limit
  5. GRB050925: Swift-BAT detection of a short burst
  6. GRB 050922B: Correction to BAT refined analysis, longer burst
  7. GRB050922B: refined XRT analysis
  8. Konus-Wind observation of GRB 050922C
  9. GRB050922B: Swift UVOT early upper limits.
  10. GRB 050922B: optical limit
  11. GRB 050922C: Swift XRT refined analysis
  12. HETE Fregate observations of GRB 050922C
  13. GRB 050922C: Swift-BAT refined analysis
  14. GRB 050922B: Swift-BAT refined analysis
  15. GRB050922C: optical observations
  16. GRB 050922C: Absorption redshift from the Nordic Optical Telescope
  17. GRB 050922C: optical obserations
  18. GRB 050922C: NOT optical observations
  19. GRB 050922A: Analysis of Swift/XRT TOO observation
  20. GRB 050922C: Swift detection of a bright burst
  21. GRB 050922C: ROTSE-IIId Refined Analysis
  22. GRB 050922C: ROTSE-III Detection of Possible Counterpart
  23. GRB 050922B: ROTSE-III Optical Limits
  24. GRB 050922B,optical observation
  25. GRB050922B: Swift-BAT detection of a weak long burst
  26. GRB050918: Possible Swift/XRT detected afterglow
  27. GRB050820B: analysis of the XMM-Newton observation
  28. GRB050916: Swift/UVOT Upper Limits
  29. GRB 050916: Swift-BAT refined analysis
  30. Swift-BAT trigger 155764 is not a GRB
  31. Swift-BAT trigger 155764 is probably not a GRB
  32. Swift trigger 155764: bad XRT centroid
  33. Swift-BAT trigger 155535 is definitely not a GRB
  34. GRB050916 : Swift-XRT refined analysis
  35. GRB 050916: XRT position
  36. GRB 050915B: Swift-BAT refined analysis
  37. GRB 050915B: Swift/UVOT Upper Limits
  38. GRB050916: Swift-BAT detection of a long weak burst
  39. GRB 050915B: XRT position
  40. GRB050915B: Swift-BAT detection of a long bright burst
  41. GRB050915: Swift/UVOT upper limits
  42. GRB 050915: KAIT optical limit
  43. GRB 050915: IR Observations
  44. GRB 050915: Swift XRT refined analysis
  45. GRB 050915: Swift-BAT refined analysis
  46. GRB050915, optical observations
  47. GRB050915: XRT position
  48. GRB 050915: ROTSE-III optical limits
  49. GRB 050915: Swift detection of a GRB
  50. GRB050911: Upper limit on X-ray afterglow
  51. Swift-BAT trigger 155072 ground analysis
  52. Swift-BAT trigger 155072 is probably not a GRB
  53. GRB050914: XRT position probably due to cosmic ray
  54. Swift is in normal operation
  55. GRB050911: Swift UVOT followup observations
  56. GRB 050911, optical content of Swift/XRT error box
  57. GRB050911: Swift-XRT position
  58. GRB 050911, optical observations
  59. GRB 050911: Swift-BAT refined analysis
  60. Later Swift-BAT triggers 154632 and 154633 RETRACTION
  61. GRB050911: Swift-BAT detection of a long burst
  62. GRB050908: detection of Swift/UVOT optical counterpart
  63. RBO GRB 050908 observations
  64. WIRO observations in I of GRB 050908
  65. GRB 050906: Possible X-ray Counterpart
  66. GRB050908: Swift/UVOT Early upper limits
  67. GRB050908 : Swift-XRT refined analysis
  68. GRB 050908: Swift-BAT refined analysis
  69. GRB 050908: Optical observations
  70. Gemini Spectroscopy of GRB 050908
  71. GRB 050908 : Swift XRT position
  72. GRB 050908: KAIT observations
  73. GRB 050908: P60 Confirmation of Optical Afterglow
  74. GRB 050908: Swift detection of a burst
  75. Swift trigger 154073 is not a GRB
  76. GRB050904: CrAO optical observations
  77. GRB 050904 BAT refined analysis of complete data set
  78. GRB 050906: MARGE Optical Limits
  79. GRB 050906: Swift-BAT refined analysis
  80. GRB 050906: Swift XRT upper limit
  81. GRB050906: P60 Observations
  82. GRB 050904: Did SWIFT/XRT see the prompt GRB emission ?
  83. GRB 050906: Bright galaxy in BAT error box
  84. GRB 050906: Swift/BAT Detection of a possible burst
  85. GRB 050904: Swift/UVOT observations
  86. GRB 050904: early Swift XRT analysis results
  87. GRB 050904: BAT refined analysis of partial data set
  88. GRB050904: P60 Observations
  89. GRB 050904: TAROT optical limits
  90. GRB050904: Swift-BAT detection of a probable burst
  91. Swift-BAT triggers 153461-153465 are not GRBs
  92. Retraction of Swift-BAT trigger #153355
  93. GRB 050824: MDM Observations
  94. GRB 050827: Swift XRT preliminary analysis results
  95. Swift Trigger #152652 is not a GRB
  96. GRB050827: Swift/UVOT upper limits
  97. GRB 050827: Optical Limit
  98. GRB 050827: XRT possible afterglow detection
  99. GRB050827: RTT150 optical observations
  100. GRB 050827: Swift-BAT refined analysis

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