Skip to main content
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"
  1. GRB061121: Keck spectroscopic observations
  2. GRB 061121: ROTSE-III Confirmation of Optical Counterpart
  3. GRB 061121: Swift detection of a bright burst with an optical counterpart
  4. GRB 060605: NIR Observations
  5. GRB 050915B: optical afterglow
  6. GRB 060111B: Swift UVOT Refined Magnitudes
  7. Swift-BAT triggers 238544 and 238546 are not GRBs
  8. GRB061110A: Correction to GCN5817
  9. GRB 061110A: refined R-band analysis
  10. GRB 061110B: NIR Observations
  11. Swift TOO observations of GRB061110A
  12. Swift/UVOT Upper Limits for GRB061110b
  13. Swift/UVOT Upper Limits for GRB061110a
  14. GRB 061110A - VLT tentative redshift
  15. GRB 061110B: Swift XRT refined analysis
  16. GRB 061110B, Swift-BAT refined analysis
  17. GRB 061110B: VLT redshift
  18. GRB061110B: Optical observations at Crni Vrh
  19. GRB 061110B: NOT optical observations
  20. GRB 061110A: Swift XRT refined analysis
  21. GRB 061110B: Swift/XRT position
  22. GRB 061110B : Liverpool Telescope Optical Afterglow Detection
  23. GRB 061110B: Swift-UVOT Initial Observation
  24. GRB 061110A, Swift-BAT refined analysis
  25. GRB 061110B: TAROT Calern observatory optical observations
  26. GRB 061110B: Swift detection of a burst
  27. GRB 061110: NOT observations
  28. GRB 061110: Candidate confirmed
  29. GRB 061110 : Optical afterglow candidate
  30. GRB 061110: ROTSE-III Optical Limits
  31. GRB 061110: Swift detection of a burst
  32. GRB061110A - Optical Non-detection
  33. Swift-BAT Trigger 237821 is a Cosmic Ray Shower event
  34. GRB 061109: optical observation
  35. GRB 061109: TAROT Calern observatory optical observations
  36. GRB 061109: Swift detection of a possible burst
  37. GRB061028: MAGIC telescope GeV observation
  38. GRB 061027: TAROT La Silla observatory optical observations
  39. GRB 061007: Third Epoch ATCA Radio Observations
  40. GRB061019: second epoch CrAO observations
  41. GRB 061028: Swift/XRT Astrometry Correction
  42. GRB 061102: Swift/UVOT Magnitude Upper Limits
  43. GRB 061102, XRT refined analysis
  44. GRB 061004: Further VLT/NTT observations
  45. Swift-BAT Trigger 236481 is a Cosmic Ray Shower event
  46. GRB061102B: Super-LOTIS observations
  47. GRB 061028: Optical R passband observations
  48. GRB 061102B: Swift detection of a possible burst
  49. GRB 061102, Swift-BAT refined analysis
  50. GRB 061102: Swift detection of a burst
  51. GRB 061028: VLA Observation
  52. GRB 061004: Swift/XRT Astrometry Correction
  53. GRB 060801: Swift/XRT Astrometry Correction
  54. GRB 061028: Futher P200 Observations
  55. GRB 061028: MDM Observations
  56. GRB 061028: P200 Observations
  57. GRB 061028: SARA upper limit
  58. GRB 061028: z band imaging
  59. GRB061028: XRT refined analysis
  60. GRB 061028: Swift/UVOT Observations
  61. GRB 061028, Swift-BAT refined analysis
  62. GRB 061028: TAROT Calern observatory late optical observations
  63. GRB 061028: TAROT Calern observatory optical observations
  64. GRB 061028: Swift detection of a burst
  65. GRB 061027, Swift refined analysis of a possible burst
  66. GRB 061027: Swift detection of a possible burst
  67. GRB061025: ROTSE-III Confirmation of Optical Counterpart
  68. GRB061025: Swift XRT refined analysis
  69. GRB061025: Swift/UVOT observations
  70. GRB 061019: MITSuME upper limits
  71. GRB 061025: REM observations
  72. GRB 061025: Gemini-S observations
  73. GRB061025: Swift XRT position
  74. GRB 061025: ROTSE-III Optical Limits
  75. GRB 061025: a long GRB detected by INTEGRAL
  76. Swift XRT boresight update
  77. GRB 061021, Swift-BAT Lag analysis
  78. Konus-Wind observation of GRB 061021
  79. GRB 061021 - VLT spectrum without lines
  80. GRB 061021: Swift-XRT refined analysis
  81. GRB 061021: Swift/UVOT Observation
  82. GRB 061021, Swift-BAT refined analysis
  83. GRB 061021: Swift detection of a burst
  84. GRB 061019: Super-LOTIS upper limit
  85. GRB060904b: optical observations
  86. GRB061019: optical observations
  87. GRB061019: optical observations
  88. GRB 061019: SARA upper limit
  89. GRB 061019: dust-scattered X-ray halo detected in Swift/XRT
  90. GRB 060930: MARGE Optical Limits
  91. GRB 061019: Swift/UVOT upper limit
  92. GRB 061019: SMARTS afterglow confirmation
  93. GRB061019: Swift XRT refined analysis
  94. GRB 061019, Swift-BAT refined analysis
  95. GRB 061019: TAROT La Silla observatory optical observations
  96. GRB 061019: REM K-band candidate afterglow
  97. GRB061019: Swift/XRT position
  98. GRB 061019: Swift-BAT detection of a burst
  99. GRB 060825: GORT Observations
  100. GRB 061007: Second Epoch ATCA Radio 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