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. GRB 050124: K-band afterglow observations
  2. GRB050126: MASTER optical limit for KECK OT
  3. GRB050126: Burst Parameters Measured by BAT
  4. GRB050126: MASTER optical observations
  5. GRB 050126: Detection of NIR afterglow with Keck/NIRC
  6. GRB 050126: Prompt XRT detection and localization
  7. GRB 050124: NIR afterglow confirmed with Keck/NIRC
  8. GRB050124: No Swift UVOT Detection of Afterglow Emission
  9. GRB 050124, SMARTS optical/IR observations
  10. GRB 050117a: Radio Observations
  11. GRB 050124 I-band observation
  12. GRB 050124: NIR Candidates from Keck/NIRC
  13. GRB050124,optical observation
  14. GRB 050124 : Lulin R-band follow-up observation
  15. GRB050124: Updated Swift XRT Position and Fluxes
  16. GRB 050124: Swift XRT Detection of X-ray Afterglow Emission
  17. GRB050124: Refined BAT position, spectral and fluence information
  18. GRB050124: Swift-BAT position of a double-peaked burst
  19. GRB 050123 : I-band follow-up observation
  20. GRB050123: optical limit 1.8h before GRB
  21. GRB050123,optical observation
  22. GRB 050123: KAIT observations
  23. GRB050123: P60 Observations
  24. GRB 050123(=H3666): A GRB Localized in Real Time by HETE
  25. CFHTLS optical transient unlikely to be a GRB
  26. Unusual optical transient (GRB ???)
  27. GRB050117a: Radio Observations
  28. GRB050117a: Refined analysis
  29. GRB 041224 and GRB 041226: BOOTES-2 simultaneous observations
  30. GRB050117: Palomar WIRC Ks-band observations
  31. GRB050117b: Swift-BAT detection of a weak burst
  32. GRB050117: optical observation
  33. GRB 050117, I-band observations
  34. GRB 050117: Optical observation
  35. GRB050117: Refined XRT position
  36. GRB050117: MASTER optical observations
  37. MASTER:GRB050117 SWIFT
  38. GRB050117: Swift-BAT detection of a long multi-peaked burst
  39. GRB050117: Swift XRT Position
  40. SGR 1806-20: RXTE/PCA pulse frequency during flare
  41. Triangulation of Short Hard GRB050112 (large error box)
  42. SGR 1806-20: Further VLA Observations
  43. SGR 1806-20: Further low frequency GMRT results
  44. SGR 1806-20: Further VLA Observations
  45. SGR1806-20: Swift-BAT observations of two additional bursts
  46. SGR1806: Optical Transient Candidates in SOHO/LASCO Images
  47. Further VLA observations of SGR 1806-20
  48. SGR 1806-20 and extragalactic short-duration GRBs
  49. Further ATCA observations of SGR 1806-20
  50. Fourth Epoch VLA observations of SGR 1806-20
  51. SGR 1806-20: Low frequency GMRT results; submission to GCN circulars
  52. SGR 1806-20: Temporal and Spectral behavior of radio transient
  53. ATCA observations of SGR 1806-20
  54. SGR 1806-20, RHESSI observations of the 041227 giant flare
  55. Third epoch observations of SGR 1806-20 with VLA
  56. Second Epoch VLA observations of SGR 1806-20
  57. Second-epoch VLA observations of SGR 1806-20
  58. SGR1806: Detection of a Sudden Ionospheric Disturbance
  59. DETECTION OF POLARIZATION OF THE RADIO EMISSION FROM SGR 1806-20
  60. VLA observations of SGR 1806-20
  61. SGR1806 VLA Observations
  62. VLA observations of SGR 1806-20
  63. SGR1806-20: RXTE-PCA observation of the 041227 super-flare
  64. GRB 041217: Optical observations
  65. SGR1806-20: Swift-BAT observation of the 041227 super-flare
  66. GRB041219, early time observations
  67. Detection of the SGR 1806-20 giant outburst back-scattered by the
  68. The giant outburst from SGR 1806-20
  69. IPN localization of giant flare from SGR1806-20
  70. Giant flare from SGR 1806-20 detected by INTEGRAL
  71. GRB041228: ROTSE-III Optical Observations
  72. GRB041228: Swift-BAT detection of a burst
  73. GRB041219; RXTE ASM Observations
  74. NIR Observations of GRB 041219
  75. GRB041226: ROTSE-III Optical Observations
  76. GRB041226: Swift-BAT detection of a burst
  77. GRB041223: decay of the afterglow
  78. GRB041224: ROTSE-III Optical Observations
  79. GRB 041224: near-infrared observations with REM
  80. GRB 041223: XRT afterglow spectrum and light curve
  81. GRB 041223 Fluence measured by Swift-BAT
  82. GRB041224: Swift-BAT detection of a soft burst
  83. GRB041223: optical and NIR observations with REM
  84. Swift-BAT Time History of GRB041219
  85. GRB 041219: TAROT optical observations
  86. GRB 041218: TAROT optical observations
  87. GRB 041223: J-band observations of the afterglow
  88. GRB 041223: Detection of Optical Transient with LCO40
  89. GRB041223: Swift XRT Detection of X-ray Afterglow Emission
  90. GRB 041219c: PROMPT Observations
  91. GRB041223: ROTSE-III Optical Observations
  92. GRB041223: Swift-BAT detection of a bright long burst
  93. GRB 041218: optical observations
  94. Very high activity of SGR 1806-20
  95. GRB 041219: Second Epoch WSRT Radio Observations
  96. GRB 041219: WSRT Radio Afterglow Detection
  97. GRB 041219: Keck IR Observations and Astrometric Refinement of the
  98. GRB 041218: Optical observations
  99. GRB 041219 : optical follow-up observations
  100. GRB041220: Swift-BAT burst

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