Skip to main content
New! CHIME and DSA-110 FRB Notices, IceCube Notices and Schema v6.1.1. 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. GRB050209: TAROT optical observations
  2. GRB 050209(=U11568): Duration and spectrum
  3. short/hard GRB 050202, optical observations
  4. GRB050209: REM optical observations
  5. GRB 050209 I-band observation
  6. GRB 050209 Optical observations
  7. GRB050209: P60 Optical Observations
  8. GRB050209 (=U11568): A Long GRB Detected by HETE
  9. GRB 050209: Optical observation
  10. GRB 050128: Radio observations
  11. Further analysis of the short Swift-BAT GRB 050202
  12. GRB 050202: Second epoch radio observations
  13. GRB 050129: Optical observations
  14. GRB050202: Radio Observations
  15. GRB 050202: Optical observations with LCO40
  16. GRB 050202: Short burst detected by Swift-BAT
  17. GRB 050128 Optical observation with REM
  18. GRB 050129: a weak long GRB detected with INTEGRAL
  19. SGR1806-20: Swift-BAT detection of a large normal burst
  20. GRB050128: Faulkes Telescope South observations
  21. GRB 050124: Radio Observations
  22. GRB 050128: near-infrared observations with REM
  23. GRB050128,optical observations
  24. GRB 050126: A NIR afterglow candidate in the revised XRT error circle
  25. GRB050126: Updated Swift XRT Position
  26. SGR 1806-20: GMRT results at 240 MHz band.
  27. SGR 1806-20: low frequency GMRT results of 2005 Jan 16.
  28. GRB 050126: Radio Observations
  29. GRB050128 Swift-BAT observations
  30. GRB 050128: Swift XRT prompt afterglow position
  31. HETE #3667: P60 Observations
  32. GRB 050124: K-band afterglow observations
  33. GRB050126: MASTER optical limit for KECK OT
  34. GRB050126: Burst Parameters Measured by BAT
  35. GRB050126: MASTER optical observations
  36. GRB 050126: Detection of NIR afterglow with Keck/NIRC
  37. GRB 050126: Prompt XRT detection and localization
  38. GRB 050124: NIR afterglow confirmed with Keck/NIRC
  39. GRB050124: No Swift UVOT Detection of Afterglow Emission
  40. GRB 050124, SMARTS optical/IR observations
  41. GRB 050117a: Radio Observations
  42. GRB 050124 I-band observation
  43. GRB 050124: NIR Candidates from Keck/NIRC
  44. GRB050124,optical observation
  45. GRB 050124 : Lulin R-band follow-up observation
  46. GRB050124: Updated Swift XRT Position and Fluxes
  47. GRB 050124: Swift XRT Detection of X-ray Afterglow Emission
  48. GRB050124: Refined BAT position, spectral and fluence information
  49. GRB050124: Swift-BAT position of a double-peaked burst
  50. GRB 050123 : I-band follow-up observation
  51. GRB050123: optical limit 1.8h before GRB
  52. GRB050123,optical observation
  53. GRB 050123: KAIT observations
  54. GRB050123: P60 Observations
  55. GRB 050123(=H3666): A GRB Localized in Real Time by HETE
  56. CFHTLS optical transient unlikely to be a GRB
  57. Unusual optical transient (GRB ???)
  58. GRB050117a: Radio Observations
  59. GRB050117a: Refined analysis
  60. GRB 041224 and GRB 041226: BOOTES-2 simultaneous observations
  61. GRB050117: Palomar WIRC Ks-band observations
  62. GRB050117b: Swift-BAT detection of a weak burst
  63. GRB050117: optical observation
  64. GRB 050117, I-band observations
  65. GRB 050117: Optical observation
  66. GRB050117: Refined XRT position
  67. GRB050117: MASTER optical observations
  68. MASTER:GRB050117 SWIFT
  69. GRB050117: Swift-BAT detection of a long multi-peaked burst
  70. GRB050117: Swift XRT Position
  71. SGR 1806-20: RXTE/PCA pulse frequency during flare
  72. Triangulation of Short Hard GRB050112 (large error box)
  73. SGR 1806-20: Further VLA Observations
  74. SGR 1806-20: Further low frequency GMRT results
  75. SGR 1806-20: Further VLA Observations
  76. SGR1806-20: Swift-BAT observations of two additional bursts
  77. SGR1806: Optical Transient Candidates in SOHO/LASCO Images
  78. Further VLA observations of SGR 1806-20
  79. SGR 1806-20 and extragalactic short-duration GRBs
  80. Further ATCA observations of SGR 1806-20
  81. Fourth Epoch VLA observations of SGR 1806-20
  82. SGR 1806-20: Low frequency GMRT results; submission to GCN circulars
  83. SGR 1806-20: Temporal and Spectral behavior of radio transient
  84. ATCA observations of SGR 1806-20
  85. SGR 1806-20, RHESSI observations of the 041227 giant flare
  86. Third epoch observations of SGR 1806-20 with VLA
  87. Second Epoch VLA observations of SGR 1806-20
  88. Second-epoch VLA observations of SGR 1806-20
  89. SGR1806: Detection of a Sudden Ionospheric Disturbance
  90. DETECTION OF POLARIZATION OF THE RADIO EMISSION FROM SGR 1806-20
  91. VLA observations of SGR 1806-20
  92. SGR1806 VLA Observations
  93. VLA observations of SGR 1806-20
  94. SGR1806-20: RXTE-PCA observation of the 041227 super-flare
  95. GRB 041217: Optical observations
  96. SGR1806-20: Swift-BAT observation of the 041227 super-flare
  97. GRB041219, early time observations
  98. Detection of the SGR 1806-20 giant outburst back-scattered by the
  99. The giant outburst from SGR 1806-20
  100. IPN localization of giant flare from SGR1806-20

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