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"

15556 results found.

  1. XRF011130: NEAT Optical Observations
  2. GRB011130 (=XRF011130): Revised Localization of an X-ray
  3. GRB001109, Radio Monitoring
  4. GRB011130 (=H1864): An X-Ray Rich GRB Detected by HETE
  5. GRB 011121: J-band observations
  6. GRB 011121: HST Scheduled
  7. GRB011121: UBRI Observations
  8. GRB 011121: Radio Observations
  9. GRB 011121 J-Band Astrometry
  10. GRB011121: fading behavior
  11. GRB011121: possible optical counterpart
  12. GRB011030, optical observation
  13. GRB 011030 I-band Observation
  14. The X-ray Flash 011030 ('GRB 011030')
  15. Non-triggered burst 011030 ("GRB 011030")
  16. GRB 010921: HST Detection of the Afterglow and Host Galaxy
  17. GRB 970828: HST Observations of the Host Galaxy
  18. GRB 000131: HST Detection of the Host Galaxy
  19. GRB 970828: HST Observations of the Host Galaxy
  20. GRB010921, optical observation
  21. GRB 011019 optical observation
  22. Optical observation of SGR 1806-20 at the 6-m SAO telescope
  23. GRB011019: Subaru Optical Observations
  24. GRB010921, optical observations
  25. GRB 011030, R-band observations
  26. GRB 010921: Possible supernova component
  27. GRB011019: NEAT Optical Observations
  28. GRB011019: ROTSE-III optical observations
  29. GRB010921, optical observation at early time
  30. GRB011019: Optical observations
  31. GRB011019, optical observations -- correction
  32. GRB011019, optical observations
  33. GRB011019: A Faint, X-ray Rich GRB localized by HETE
  34. GRB 010921: The afterglow of HETE #1761
  35. Optical Observations of the field of HETE trigger #1793/GRB 011012?
  36. Optical Observations of the field of HETE trigger #1793/GRB 011012?
  37. GRB010928(=H1770): Localization of a Long GRB by HETE
  38. GRB010923(=H1764): A Short Duration GRB Detected by HETE
  39. GRB010921, negative optical observations
  40. GRB010921 field photometry
  41. GRB010921 Optical Observations
  42. IPN triangulation of GRB010921 (=H1761)
  43. H1761: A Bright GRB Detected by HETE
  44. HETE Trigger #1760 (GRB 010920B?): new optical source = asteroid
  45. HETE Trigger #1760 (GRB 010920B?): a new optical source
  46. HETE Trigger #1759 (GRB 010920?) optical observations
  47. GRB001109, Host Galaxy Astrometry
  48. GRB000926, Host Galaxy Observations
  49. GRB001109, Host Galaxy Spectroscopic Observations
  50. Probable SGR or Short Duration GRB Detected by HETE
  51. GRB000926 Host Galaxy Observations
  52. GRB 010222 - WHT BVRI images
  53. GRB 010629 Optical Observations
  54. GRB010629: Optical Observations
  55. SGR1900+14: High Fluence Burst Localized by HETE
  56. GRB010629, optical observations
  57. GRB010629: A Burst Localized by HETE
  58. SGR1900+14: Second Burst Localized by HETE
  59. SGR1900+14: A Burst Localized by HETE
  60. SGR1806-20: A Second, Intense Burst Localized by HETE
  61. GRB 00630: Host Galaxy
  62. SGR1806-20: Localization by HETE
  63. GRB000418: HST/STIS Second-epoch Observations
  64. GRB010214, optical observations
  65. GRB010412, field photometry
  66. GRB 010326b Optical Observations
  67. GRB010412: Optical observations
  68. GRB010412: Optical observations
  69. GRB010324, revised field photometry
  70. GRB010326B, field photometry
  71. GRB010326, field photometry
  72. Further Optical Observations of GRB 010324
  73. GRB010222, CXO X-ray observations
  74. GRB 010326A: Further optical observations
  75. GRB 010326B: Optical observations
  76. GRB010324, optical observations
  77. GRB010326B: Localization by HETE (2nd GRB for this date)
  78. GRB 010326: Optical observations
  79. GRB 010326 optical observations
  80. GRB010326: Refined Localization by HETE
  81. GRB010326: Localization by HETE
  82. Optical Observations of GRB 010324
  83. GRB010222, late-time optical observation
  84. GRB010222 - Optical observation
  85. GRB 010222, Optical Observations
  86. GRB010220 optical obsercations
  87. GRB010222 - Optical observation
  88. GRB 010222: High-Resolution Keck Spectroscopy
  89. GRB010222: Optical observation and decay
  90. GRB 010214, I-band data
  91. GRB 010222 HST/Chandra TOO
  92. GRB 010222
  93. GRB010222: R-band data
  94. GRB010222 Optical observations
  95. GRB 010222: Keck Spectroscopy
  96. GRB010222, possible increase of optical decay slope
  97. GRB 010222 Kyoto optical observation
  98. GRB010222: fading behavior
  99. GRB 010222 BV optical observations
  100. GRB010220, Optical Observations

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