Skip to main content
Updates to LVK & CHIME Notices, Schema v7.2.3! 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 011121: Errata URL
  2. GRB 011121
  3. GRB011130 (=H1864): An X-Ray Rich GRB Detected by HETE
  4. GRB 011121: J-band observations
  5. GRB 011121: NIR observations, host galaxy?
  6. GRB010921 - Milagro GeV/TeV Observations
  7. GRB 011121: HST Scheduled
  8. GRB011121: fainter still
  9. Correction: GCN1157 (GRB 011121)
  10. GRB011121: UBRI Observations
  11. GRB011121
  12. GRB 011121: Radio Observations
  13. GRB 011121 J-Band Astrometry
  14. GRB011121: continued decay
  15. GRB 011121: Detection of Bright IR Counterpart
  16. GRB011121: possible redshift, continued decay
  17. GRB011121: fading behavior
  18. GRB011121: possible optical counterpart
  19. GRB011121: BeppoSAX-WFC refined positions
  20. IPN triangulation of GRB011121
  21. BEPPOSAX GRB011121
  22. GRB 011030: TNG K-band observation
  23. XRF011030: J and K band observations
  24. GRB011030, optical observation
  25. XRF011030: Chandra Observations
  26. GRB 011030: K-band observations
  27. GRB011030: Z-band observations
  28. GRB 011030 R band observations
  29. GRB 011030 I-band Observation
  30. The X-ray Flash 011030 ('GRB 011030')
  31. Non-triggered burst 011030 ("GRB 011030")
  32. The Radio Afterglow from the X-ray Rich GRB 011030
  33. GRB 010921: HST Detection of the Afterglow and Host Galaxy
  34. GRB 970828: HST Observations of the Host Galaxy
  35. GRB 000131: HST Detection of the Host Galaxy
  36. GRB 970828: HST Observations of the Host Galaxy
  37. GRB010921, optical observation
  38. GRB 011019 optical observation
  39. Optical observation of SGR 1806-20 at the 6-m SAO telescope
  40. GRB011019: Subaru Optical Observations
  41. GRB 011030 I-band Observations
  42. GRB 011030 K-band Observations
  43. GRB010921, optical observations
  44. GRB 011030, WSRT radio observations
  45. GRB011030 - further refinement WFC position
  46. GRB 011030, Radio observations
  47. GRB011030: radio search
  48. GRB 011030, R-band observations
  49. X-ray rich GRB011030: BeppoSAX refined positions
  50. BeppoSAX ALERT: Possible X-ray rich GRB011030
  51. GRB 010921: Possible supernova component
  52. GRB011019: NEAT Optical Observations
  53. GRB011019: ROTSE-III optical observations
  54. GRB010921, optical observation at early time
  55. GRB 010921, I-band observations
  56. GRB011019: Optical observations
  57. GRB011019, optical observations -- correction
  58. GRB011019, optical observations
  59. GRB011019: A Faint, X-ray Rich GRB localized by HETE
  60. GRB010921: Spectroscopy of the Host Galaxy
  61. GRB 010921: The afterglow of HETE #1761
  62. Optical Observations of the field of HETE trigger #1793/GRB 011012?
  63. Optical Observations of the field of HETE trigger #1793/GRB 011012?
  64. GRB010923 as seen by BeppoSAX GRBM
  65. GRB010928(=H1770): Localization of a Long GRB by HETE
  66. GRB010923(=H1764): A Short Duration GRB Detected by HETE
  67. GRB010921, negative optical observations
  68. GRB010921 field photometry
  69. GRB010921 Optical Observations
  70. GRB 010921 DPOSS Images Available
  71. IPN triangulation of GRB010921 (=H1761)
  72. H1761: A Bright GRB Detected by HETE
  73. HETE Trigger #1760 (GRB 010920B?): new optical source = asteroid
  74. HETE Trigger #1760 (GRB 010920B?): a new optical source
  75. HETE Trigger #1759 (GRB 010920?) optical observations
  76. GRB001109, Host Galaxy Astrometry
  77. GRB000926, Host Galaxy Observations
  78. GRB001109, Host Galaxy Spectroscopic Observations
  79. Probable SGR or Short Duration GRB Detected by HETE
  80. GRB000926 Host Galaxy Observations
  81. GRB 010222: HST observations -- host galaxy and late-time decay
  82. BeppoSAX/GRBM detection of GRB 010801
  83. GCN and HETE status
  84. Dramatic Increase in the Rate of X-ray Bursts Reported by HETE
  85. BeppoSAX/GRBM detection of GRB010728
  86. GRB 010222 - WHT BVRI images
  87. SGR1900+14 burst seen by HETE: BeppoSAX data
  88. GRB 010629 Optical Observations
  89. GRB010629: Optical Observations
  90. SGR1900+14: High Fluence Burst Localized by HETE
  91. GRB010629, optical observations
  92. IPN triangulation of GRB010629
  93. GRB010629: A Burst Localized by HETE
  94. SGR1900+14: Second Burst Localized by HETE
  95. SGR1900+14: A Burst Localized by HETE
  96. Possible burst from SGR1806-20
  97. IPN detection of SGR1900+14
  98. SGR1806-20: A Second, Intense Burst Localized by HETE
  99. GRB 00630: Host Galaxy
  100. SGR1806-20: Localization by HETE

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