Skip to main content
Circulars over Kafka event name backfill. 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"

24600 results found.

  1. Non-triggered burst 011030 ("GRB 011030")
  2. The Radio Afterglow from the X-ray Rich GRB 011030
  3. GRB 010921: HST Detection of the Afterglow and Host Galaxy
  4. GRB 970828: HST Observations of the Host Galaxy
  5. GRB 000131: HST Detection of the Host Galaxy
  6. GRB 970828: HST Observations of the Host Galaxy
  7. Optical observation of SGR 1806-20 at the 6-m SAO telescope
  8. GRB011019: Subaru Optical Observations
  9. GRB 011030 I-band Observations
  10. GRB 011030 K-band Observations
  11. GRB010921, optical observations
  12. GRB011030 - further refinement WFC position
  13. GRB 011030, Radio observations
  14. GRB011030: radio search
  15. GRB 010921: Possible supernova component
  16. GRB010921, optical observation at early time
  17. GRB 010921, I-band observations
  18. GRB011019, optical observations
  19. GRB011019: A Faint, X-ray Rich GRB localized by HETE
  20. GRB 010921: The afterglow of HETE #1761
  21. Optical Observations of the field of HETE trigger #1793/GRB 011012?
  22. Optical Observations of the field of HETE trigger #1793/GRB 011012?
  23. GRB010923 as seen by BeppoSAX GRBM
  24. GRB010928(=H1770): Localization of a Long GRB by HETE
  25. GRB010923(=H1764): A Short Duration GRB Detected by HETE
  26. GRB010921, negative optical observations
  27. GRB010921 field photometry
  28. H1761: A Bright GRB Detected by HETE
  29. GRB000926, Host Galaxy Observations
  30. GRB001109, Host Galaxy Spectroscopic Observations
  31. Probable SGR or Short Duration GRB Detected by HETE
  32. GCN and HETE status
  33. Dramatic Increase in the Rate of X-ray Bursts Reported by HETE
  34. GRB 010222 - WHT BVRI images
  35. SGR1900+14 burst seen by HETE: BeppoSAX data
  36. GRB 010629 Optical Observations
  37. SGR1900+14: High Fluence Burst Localized by HETE
  38. GRB010629, optical observations
  39. GRB010629: A Burst Localized by HETE
  40. SGR1900+14: Second Burst Localized by HETE
  41. SGR1900+14: A Burst Localized by HETE
  42. SGR1806-20: A Second, Intense Burst Localized by HETE
  43. SGR1806-20: Localization by HETE
  44. HETE Fully-Automated GCN Notices
  45. GRB000301C: Late-time HST/STIS observation
  46. GRB010518: a faint BeppoSAX detection
  47. GRB000418: HST/STIS Second-epoch Observations
  48. X-ray precursors to the large flare from SGR 1900+14
  49. GRB010427, Gamma Ray Observations
  50. SGR 1900+14: No evidence of extended X-ray emission
  51. SGR 1900+14 : RXTE observations
  52. BeppoSAX/NFI Follow-up Observation of SGR 1900+14
  53. SGR 1900+14: Correction to GCN 1049
  54. GRB 010222 /corrections to VBT data
  55. Millimeter observation of SGR 1900+14
  56. SGR 1900+14: Detection of extended X-ray emission
  57. SGR 1900+14, Chandra observations
  58. SGR1900+14, I-band observations
  59. GRB010412, field photometry
  60. Giant flare from SGR1900+14
  61. GRB 010326b Optical Observations
  62. GRB010412: BeppoSAX GRBM and WFC observations
  63. GRB010324, revised field photometry
  64. REVISED LOCATION OF GRB010326A
  65. GRB 980326: Late-time HST/STIS observations
  66. GRB010324, field photometry
  67. GRB010326B, field photometry
  68. GRB010326, field photometry
  69. GRB010220, field photometry
  70. Further Optical Observations of GRB 010324
  71. GRB010222, CXO X-ray observations
  72. GRB010324, optical observations
  73. GRB010326B: Localization by HETE (2nd GRB for this date)
  74. GRB 010326 optical observations
  75. GRB010326: Refined Localization by HETE
  76. GRB010326: Localization by HETE
  77. Optical Observations of GRB 010324
  78. GRB010222, late-time optical observation
  79. Support extension to the BeppoSAX mission
  80. GRB 010222 - HEGRA GeV/TeV Observations
  81. GRB010222: Chandra X-ray Observatory Observation
  82. GRB010222: Sub-millimeter vanishing act
  83. GRB010222 - Optical observation
  84. GRB 010222, Optical Observations
  85. GRB010222 - Optical observation
  86. GRB 010222: High-Resolution Keck Spectroscopy
  87. GRB 010214, I-band data
  88. GRB 010222
  89. GRB010222 further R-band photometry
  90. GRB010222: R-band data
  91. GRB 010222: Keck Spectroscopy
  92. GRB010214, field photometry
  93. GRB010222, field photometry
  94. GRB010222 further R-band photometry
  95. GRB010222, possible increase of optical decay slope
  96. GRB 010222 Kyoto optical observation
  97. GRB010222 R-BAND OBSERVATION
  98. GRB010214 follow-up from Hanle
  99. GRB 010222: Near-IR Observations
  100. GRB 010222: 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