Skip to main content
New! Browse Circulars by Event, Advanced Search, Sample Codes, Schema Release. 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"

24797 results found.

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