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. GRB050123: optical limit 1.8h before GRB
  2. GRB050123,optical observation
  3. GRB 050123: KAIT observations
  4. GRB050123: P60 Observations
  5. GRB 050123(=H3666): A GRB Localized in Real Time by HETE
  6. CFHTLS optical transient unlikely to be a GRB
  7. Unusual optical transient (GRB ???)
  8. GRB050117a: Radio Observations
  9. GRB050117a: Refined analysis
  10. GRB 041224 and GRB 041226: BOOTES-2 simultaneous observations
  11. GRB050117: Palomar WIRC Ks-band observations
  12. GRB050117b: Swift-BAT detection of a weak burst
  13. GRB050117: optical observation
  14. GRB 050117, I-band observations
  15. GRB 050117: Optical observation
  16. GRB050117: Refined XRT position
  17. GRB050117: MASTER optical observations
  18. MASTER:GRB050117 SWIFT
  19. GRB050117: Swift-BAT detection of a long multi-peaked burst
  20. GRB050117: Swift XRT Position
  21. SGR 1806-20: RXTE/PCA pulse frequency during flare
  22. Triangulation of Short Hard GRB050112 (large error box)
  23. SGR 1806-20: Further VLA Observations
  24. SGR 1806-20: Further low frequency GMRT results
  25. SGR 1806-20: Further VLA Observations
  26. SGR1806-20: Swift-BAT observations of two additional bursts
  27. SGR1806: Optical Transient Candidates in SOHO/LASCO Images
  28. Further VLA observations of SGR 1806-20
  29. SGR 1806-20 and extragalactic short-duration GRBs
  30. Further ATCA observations of SGR 1806-20
  31. Fourth Epoch VLA observations of SGR 1806-20
  32. SGR 1806-20: Low frequency GMRT results; submission to GCN circulars
  33. SGR 1806-20: Temporal and Spectral behavior of radio transient
  34. ATCA observations of SGR 1806-20
  35. SGR 1806-20, RHESSI observations of the 041227 giant flare
  36. Third epoch observations of SGR 1806-20 with VLA
  37. Second Epoch VLA observations of SGR 1806-20
  38. Second-epoch VLA observations of SGR 1806-20
  39. SGR1806: Detection of a Sudden Ionospheric Disturbance
  40. DETECTION OF POLARIZATION OF THE RADIO EMISSION FROM SGR 1806-20
  41. VLA observations of SGR 1806-20
  42. SGR1806 VLA Observations
  43. VLA observations of SGR 1806-20
  44. SGR1806-20: RXTE-PCA observation of the 041227 super-flare
  45. GRB 041217: Optical observations
  46. SGR1806-20: Swift-BAT observation of the 041227 super-flare
  47. GRB041219, early time observations
  48. Detection of the SGR 1806-20 giant outburst back-scattered by the
  49. The giant outburst from SGR 1806-20
  50. IPN localization of giant flare from SGR1806-20
  51. Giant flare from SGR 1806-20 detected by INTEGRAL
  52. GRB041228: ROTSE-III Optical Observations
  53. GRB041228: Swift-BAT detection of a burst
  54. GRB041219; RXTE ASM Observations
  55. NIR Observations of GRB 041219
  56. GRB041226: ROTSE-III Optical Observations
  57. GRB041226: Swift-BAT detection of a burst
  58. GRB041223: decay of the afterglow
  59. GRB041224: ROTSE-III Optical Observations
  60. GRB 041224: near-infrared observations with REM
  61. GRB 041223: XRT afterglow spectrum and light curve
  62. GRB 041223 Fluence measured by Swift-BAT
  63. GRB041224: Swift-BAT detection of a soft burst
  64. GRB041223: optical and NIR observations with REM
  65. Swift-BAT Time History of GRB041219
  66. GRB 041219: TAROT optical observations
  67. GRB 041218: TAROT optical observations
  68. GRB 041223: J-band observations of the afterglow
  69. GRB 041223: Detection of Optical Transient with LCO40
  70. GRB041223: Swift XRT Detection of X-ray Afterglow Emission
  71. GRB 041219c: PROMPT Observations
  72. GRB041223: ROTSE-III Optical Observations
  73. GRB041223: Swift-BAT detection of a bright long burst
  74. GRB 041218: optical observations
  75. Very high activity of SGR 1806-20
  76. GRB 041219: Second Epoch WSRT Radio Observations
  77. GRB 041219: WSRT Radio Afterglow Detection
  78. GRB 041219: Keck IR Observations and Astrometric Refinement of the
  79. GRB 041218: Optical observations
  80. GRB 041219 : optical follow-up observations
  81. GRB041220: Swift-BAT burst
  82. Deep RAPTOR observations during GRB 041219
  83. GRB 041218 Optical Observations
  84. GRB 041219 Optical Observations
  85. GRB041219c: Third Burst in One Day from Swift-BAT
  86. GRB041219: Optical Afterglow Detection
  87. GRB041219: Continued NIR Observations
  88. GRB041219b: A Swift-BAT burst
  89. GRB 041219 ,optical observation
  90. GRB 041219: Radio Afterglow Detection
  91. GRB 041218 : Radio Observations
  92. GRB 041218: R-band optical observations
  93. GRB041218: Liverpool Telescope optical observations
  94. GRB041218: optical observations
  95. GRB041219: Confirmed NIR Afterglow
  96. GRB041218: Continued P60 Optical Observations
  97. Swift-BAT detection of the bright long burst GRB041219
  98. GRB 041218: Optical Observation
  99. GRB 041219: Infrared Afterglow Candidate
  100. GRB041219, BVRcIc field calibration

Advanced

Download all Circulars as a .tar.gz archive (updated once a day):
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