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. GRB061126: update on the Swift-XRT afterglow light curve
  2. Corrections for Swift/UVOT Exposure Times for GRBs 061110B and 061121
  3. GRB 061201: UVOT Observations of a Fading Optical Afterglow
  4. GRB 061202: TORTOREM optical upper limits
  5. GRB 061201: VLT optical decay
  6. GRB 061201: SOAR Confirmation of Candidate Afterglow
  7. GRB061126 : NMSU 1.0m observations
  8. GRB 061202: Swift XRT refined analysis
  9. GRB061202: FRAM early follow-up limit
  10. GRB061202 optical limit by "Pi of the Sky"
  11. Konus-Wind observation of GRB 061201
  12. GRB061202: optical/NIR observations with REM
  13. GRB061202: Swift/UVOT Upper Limits
  14. GRB 061202, Swift-BAT refined analysis
  15. GRB 061202: Swift detection of a burst
  16. GRB 061201: Swift XRT Team refined analysis
  17. GRB 061201: VLT optical observations
  18. GRB 061201: Initial UVOT Observations
  19. GRB 061201, Swift-BAT refined analysis of the SHB
  20. GRB 061201: Swift detection of a short hard burst
  21. GRB 061201: Coincidence with a Galaxy Cluster
  22. GRB 061122: GETS observation
  23. GRB 061121, SMARTS optical/IR observations
  24. GRB 061121: flattening of the decay
  25. INT+WFC observations of GRB 061126
  26. GRB 061126: Possible Jet Break
  27. GRB 061121: Second Epoch ATCA Radio Observations
  28. GRB 061126: RAPTOR Optical Detection During Gamma-Ray Emission
  29. Swift XRT on-board boresight update
  30. GRB 061121: ATCA & WSRT Radio Observations
  31. GRB061121: optical observations
  32. GRB 061126: Early Super-LOTIS Observations
  33. GRB 061126: optical observation
  34. RHESSI Spectrum of GRB061126
  35. GRB 061126: Tautenburg afterglow observations
  36. GRB061126: Optical afterglow observations from MIRO
  37. GRB061126: Optical afterglow observations from MIRO
  38. GRB 061126 : SDSS Pre-Burst Observations
  39. GRB 061126: Swift-XRT refined analysis
  40. GRB 061126: Swift/UVOT Observations
  41. GRB 061126, Swift-BAT refined analysis
  42. GRB 061126: SARA Observations
  43. GRB 061126: Early Detection of the IR Afterglow
  44. GRB 061126: Faulkes Telescope North Optical Observations
  45. GRB 061126: Swift/UVOT Afterglow Detection
  46. GRB 061126: XRT position
  47. GRB 061126: Swift detection of a burst
  48. GRB 061121: MDM Continued Monitoring
  49. GRB 061122: Confirmation of X-ray/Optical Afterglow
  50. GRB 061121: MDM Continuing Optical Decay
  51. GRB061121: optical observations
  52. GRB 061122: Candidate Optical Afterglow
  53. GRB 061121: Ep,i - Eiso correlation
  54. GRB 061121: MDM Optical Decay
  55. GRB061122: Swift/UVOT Optical Observations
  56. GRB 061121: ART detection in Ic
  57. GRB061121: P60 Observations
  58. Radio detection of GRB 061121
  59. GRB061122: Swift-XRT position
  60. Konus-Wind observation of GRB 061122
  61. GRB 061121: MDM Optical Observations
  62. GRB 061121 declared "Burst of Interest" by Swift team
  63. RHESSI Spectrum of GRB061121
  64. Konus-Wind and Konus-A observations of GRB 061121
  65. INTEGRAL results on GRB 061122
  66. Swift-BAT trigger 239987 is not a GRB
  67. GRB 061122A: a long GRB detected by INTEGRAL
  68. GRB 061121: Swift/UVOT Observations
  69. GRB 061121: Swift-XRT Team Refined Analysis
  70. GRB 061121, Swift-BAT refined analysis
  71. GRB061121, optical observation
  72. GRB 061121 : Planned XMM-Newton observation
  73. GRB 061121: Optical observation at the KANATA 1.5m telescope
  74. GRB 061121: Faulkes Telescope North Optical Observation
  75. GRB061121: Spectroscopic Redshift
  76. GRB061121: Keck spectroscopic observations
  77. GRB 061121: ROTSE-III Confirmation of Optical Counterpart
  78. GRB 061121: Swift detection of a bright burst with an optical counterpart
  79. GRB 060605: NIR Observations
  80. GRB 050915B: optical afterglow
  81. GRB 060111B: Swift UVOT Refined Magnitudes
  82. Swift-BAT triggers 238544 and 238546 are not GRBs
  83. GRB061110A: Correction to GCN5817
  84. GRB 061110A: refined R-band analysis
  85. GRB 061110B: NIR Observations
  86. Swift TOO observations of GRB061110A
  87. Swift/UVOT Upper Limits for GRB061110b
  88. Swift/UVOT Upper Limits for GRB061110a
  89. GRB 061110A - VLT tentative redshift
  90. GRB 061110B: Swift XRT refined analysis
  91. GRB 061110B, Swift-BAT refined analysis
  92. GRB 061110B: VLT redshift
  93. GRB061110B: Optical observations at Crni Vrh
  94. GRB 061110B: NOT optical observations
  95. GRB 061110A: Swift XRT refined analysis
  96. GRB 061110B: Swift/XRT position
  97. GRB 061110B : Liverpool Telescope Optical Afterglow Detection
  98. GRB 061110B: Swift-UVOT Initial Observation
  99. GRB 061110A, Swift-BAT refined analysis
  100. GRB 061110B: TAROT Calern observatory optical 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