Skip to main content
New! BOOM Notices and Schema v7.0.0. 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"
  1. Photometric calibration of Swift/UVOT and Re-analysis of Swift/UVOT GRB 050922C data
  2. GRB051006: optical observations
  3. GRB 051012: Swift-BAT detection of burst yesterday
  4. Swift trigger 159578 is not a burst
  5. Swift-BAT Trigger 159578 is a possible burst
  6. GRB050805A: Rc optical observations
  7. GRB 051006: Swift/UVOT Upper Limits
  8. IBAS Alert 2675 : not a GRB
  9. GRB051008: optical candidate
  10. GRB 051008: - a high redshift high-luminosity burst?
  11. GRB 051008 - a low redshift low-luminosity burst?
  12. IBAS Alert 2673: not a real GRB
  13. GRB051011: bright nebulae near error box
  14. GRB051011: MASTER optical observation
  15. GRB051008: optical observation
  16. GRB051008: Swift XRT refined analysis
  17. GRB051008 - Swift UVOT upper limits
  18. Konus-Wind observation of GRB 051008
  19. GRB051008: Final refined analysis of the Swift-BAT burst
  20. GRB 051008: R-band upper limit
  21. GRB051008: Refined analysis of the Swift-BAT burst
  22. GRB051008: Radio Observation
  23. GRB 051008: Swift XRT position
  24. GRB 051008, optical observations
  25. GRB 051008: early Swift XRT analysis
  26. GRB 051008: Swift UVOT Candidate
  27. GRB051008: Swift-BAT detection of a bright burst
  28. GRB 051006: P60 Observations
  29. grb test
  30. GRB 051006: XRT refined analysis
  31. Swift-BAT trigger 158700 is a probable Cosmic Ray Shower Event
  32. GRB 051006: optical observations at Sierra Nevada
  33. GRB051006: Refined analysis of the Swift-BAT burst
  34. GRB 051006: XRT position
  35. GRB051006: Swift detection of a burst
  36. GRB 050906, summary of radio observations
  37. Swift-BAT triggers 158261 and 158262 Retraction
  38. GRB051001: Swift UVOT Upper Limits
  39. GRB 050925: Second Epoch WSRT Radio Observations
  40. GRB 051001: Swift XRT refined analysis
  41. GRB 051001, optical observations at Mt. John
  42. GRB 051001: I-band limit
  43. GRB 051001: AAT infra-red observations
  44. GRB 051001: Swift-BAT refined analysis
  45. GRB 051001: Swift Detection of a Burst
  46. GRB 051001: ROTSE-III Optical Limits
  47. GRB050908: optical observations
  48. GRB050922C: optical observation
  49. GRB050922B: optical limit
  50. GRB 050922C: further VLT observations
  51. GRB 050820A: NIR photometry at the TNG
  52. GRB050922C: UVES/VLT high resolution spectroscopy
  53. GRB050925: Swift/XRT limits
  54. GRB/SGR 050925: IR Observations
  55. GRB050922C - Swift UVOT preliminary analysis
  56. GRB 050922C: break in the lightcurve
  57. GRB 050925: WSRT Radio Observations
  58. GRB050925: Swift UVOT upper limits
  59. Refined analysis of the Swift-BAT soft short burst
  60. GRB 050925 : I-band observation at Xinglong observatory
  61. GRB050925: Faulkes Telescope North R-band limit
  62. GRB050925: Swift-BAT detection of a short burst
  63. GRB 050922B: Correction to BAT refined analysis, longer burst
  64. GRB050922C: TNG spectroscopic observations
  65. GRB050922B: refined XRT analysis
  66. Konus-Wind observation of GRB 050922C
  67. GRB 050922C: Refined redshift
  68. GRB050922B: Swift UVOT early upper limits.
  69. GRB OT observation
  70. GRB050922C: observation at MonteBoo
  71. INT 2.5m limit for GRB050922B
  72. GRB 050922B: optical limit
  73. GRB050922C: Optical Observations
  74. GRB 050922C: Swift XRT refined analysis
  75. HETE Fregate observations of GRB 050922C
  76. GRB 050922C: Swift-BAT refined analysis
  77. GRB 050922B: Swift-BAT refined analysis
  78. GRB050922C: optical observations
  79. GRB 050922C: Absorption redshift from the Nordic Optical Telescope
  80. GRB 050922C: optical obserations
  81. GRB 050922C: NOT optical observations
  82. GRB 050922A: Analysis of Swift/XRT TOO observation
  83. GRB 050922C: Swift detection of a bright burst
  84. GRB 050922C: ROTSE-IIId Refined Analysis
  85. GRB 050922C: ROTSE-III Detection of Possible Counterpart
  86. GRB 050922B: ROTSE-III Optical Limits
  87. GRB 050922B,optical observation
  88. GRB050922B: Swift-BAT detection of a weak long burst
  89. Possible GRB 050922 detected by INTEGRAL
  90. GRB050918: Possible Swift/XRT detected afterglow
  91. GRB050820B: analysis of the XMM-Newton observation
  92. GRB050916: Swift/UVOT Upper Limits
  93. GRB 050916: Swift-BAT refined analysis
  94. GRB 050918 - A long GRB detected by INTEGRAL
  95. GRB 050915a: Radio Observations
  96. Swift-BAT trigger 155764 is not a GRB
  97. Swift-BAT trigger 155764 is probably not a GRB
  98. Swift trigger 155764: bad XRT centroid
  99. Swift-BAT trigger 155535 is definitely not a GRB
  100. GRB050916 : Swift-XRT 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