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"

42779 results found.

  1. GRB011121: continued decay
  2. GRB 011121: Detection of Bright IR Counterpart
  3. GRB011121: possible redshift, continued decay
  4. GRB011121: fading behavior
  5. GRB011121: possible optical counterpart
  6. IPN triangulation of GRB011121
  7. BEPPOSAX GRB011121
  8. GRB 011030: TNG K-band observation
  9. XRF011030: J and K band observations
  10. GRB011030, optical observation
  11. XRF011030: Chandra Observations
  12. GRB 011030: K-band observations
  13. GRB011030: Z-band observations
  14. GRB 011030 R band observations
  15. GRB 011030 I-band Observation
  16. The X-ray Flash 011030 ('GRB 011030')
  17. Non-triggered burst 011030 ("GRB 011030")
  18. The Radio Afterglow from the X-ray Rich GRB 011030
  19. GRB 010921: HST Detection of the Afterglow and Host Galaxy
  20. GRB 970828: HST Observations of the Host Galaxy
  21. GRB 000131: HST Detection of the Host Galaxy
  22. GRB 970828: HST Observations of the Host Galaxy
  23. GRB010921, optical observation
  24. GRB 011019 optical observation
  25. Optical observation of SGR 1806-20 at the 6-m SAO telescope
  26. GRB011019: Subaru Optical Observations
  27. GRB 011030 I-band Observations
  28. GRB 011030 K-band Observations
  29. GRB010921, optical observations
  30. GRB 011030, WSRT radio observations
  31. GRB011030 - further refinement WFC position
  32. GRB 011030, Radio observations
  33. GRB 011030, R-band observations
  34. BeppoSAX ALERT: Possible X-ray rich GRB011030
  35. GRB 010921: Possible supernova component
  36. GRB011019: NEAT Optical Observations
  37. GRB011019: ROTSE-III optical observations
  38. GRB010921, optical observation at early time
  39. GRB011019: Optical observations
  40. GRB011019: A Faint, X-ray Rich GRB localized by HETE
  41. GRB010921: Spectroscopy of the Host Galaxy
  42. GRB 010921: The afterglow of HETE #1761
  43. Optical Observations of the field of HETE trigger #1793/GRB 011012?
  44. Optical Observations of the field of HETE trigger #1793/GRB 011012?
  45. GRB010923 as seen by BeppoSAX GRBM
  46. GRB010928(=H1770): Localization of a Long GRB by HETE
  47. GRB010923(=H1764): A Short Duration GRB Detected by HETE
  48. GRB010921, negative optical observations
  49. GRB010921 field photometry
  50. GRB010921 Optical Observations
  51. GRB 010921 DPOSS Images Available
  52. IPN triangulation of GRB010921 (=H1761)
  53. H1761: A Bright GRB Detected by HETE
  54. HETE Trigger #1760 (GRB 010920B?): new optical source = asteroid
  55. HETE Trigger #1760 (GRB 010920B?): a new optical source
  56. HETE Trigger #1759 (GRB 010920?) optical observations
  57. GRB001109, Host Galaxy Astrometry
  58. GRB000926, Host Galaxy Observations
  59. GRB001109, Host Galaxy Spectroscopic Observations
  60. Probable SGR or Short Duration GRB Detected by HETE
  61. GRB000926 Host Galaxy Observations
  62. GRB 010222: HST observations -- host galaxy and late-time decay
  63. BeppoSAX/GRBM detection of GRB 010801
  64. GCN and HETE status
  65. Dramatic Increase in the Rate of X-ray Bursts Reported by HETE
  66. BeppoSAX/GRBM detection of GRB010728
  67. GRB 010222 - WHT BVRI images
  68. SGR1900+14 burst seen by HETE: BeppoSAX data
  69. GRB010629: Optical Observations
  70. SGR1900+14: High Fluence Burst Localized by HETE
  71. GRB010629, optical observations
  72. IPN triangulation of GRB010629
  73. GRB010629: A Burst Localized by HETE
  74. SGR1900+14: Second Burst Localized by HETE
  75. SGR1900+14: A Burst Localized by HETE
  76. Possible burst from SGR1806-20
  77. IPN detection of SGR1900+14
  78. SGR1806-20: A Second, Intense Burst Localized by HETE
  79. GRB 00630: Host Galaxy
  80. SGR1806-20: Localization by HETE
  81. IPN triangulation of GRB010613
  82. IPN triangulation of GRB010612
  83. HETE Fully-Automated GCN Notices
  84. GRB000301C: Late-time HST/STIS observation
  85. GRB010518: a faint BeppoSAX detection
  86. GRB000418: HST/STIS Second-epoch Observations
  87. X-ray precursors to the large flare from SGR 1900+14
  88. GRB010214, optical observations
  89. GRB010427, Gamma Ray Observations
  90. SGR 1900+14: No evidence of extended X-ray emission
  91. SGR 1900+14 : RXTE observations
  92. BeppoSAX/NFI Follow-up Observation of SGR 1900+14
  93. SGR1900+14 - correction
  94. SGR1900+14
  95. SGR 1900+14: Correction to GCN 1049
  96. GRB 010222 /corrections to VBT data
  97. Millimeter observation of SGR 1900+14
  98. SGR 1900+14: Detection of extended X-ray emission
  99. SGR 1900+14, Chandra observations
  100. Chandra Observations of SGR 1900+14

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