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"

25042 results found.

  1. GRB 020124: Optical afterglow
  2. GRB020124(=H1896): Localization of a Long GRB by HETE
  3. Possible optical counterpart to a GRB
  4. GRB011212, Optical Observations
  5. Optical polarization observations for GRB011211
  6. GRB 011211: Detection of the Probable Host Galaxy
  7. GRB 011130 and GRB 011212 - Milagro GeV/TeV Observations
  8. GRB 011130: Optical Observations of X-ray and Radio Sources
  9. GRB 011212: optical observation at Asiago
  10. GRB 011211: Evidence for an Optical Break
  11. GRB 011211: TNG Spectroscopic Observations
  12. optical follow-up of GRB(XRF) 011211
  13. GRB 011212: optical observation at Oslo (relayed)
  14. GRB 011211, Optical Observations
  15. GRB011212, BVRI field photometry
  16. GRB011211, BVRI field photometry
  17. GRB011212 (=H10001): An X-Ray Rich GRB Detected by HETE
  18. Fading of the optical source associated of XRF 011211
  19. GRB 011211 Optical Observations: Likely Afterglow
  20. GRB011130 (=XRF011130): Further analysis of Chandra Target of
  21. GRB011130 (XRF011130) Chandra Observations
  22. GRB011130 (=XRF011130): Scheduled Target of Opportunity
  23. GRB 011130, K band observations
  24. GRB011130, optical observations
  25. GRB011130 (=XRF011130): Second Revised Localization by HETE
  26. GRB011130 (XRF011130) SDSS PT i-band observations
  27. XRF011130: Infrared Observations
  28. GRB 011121
  29. GRB011130 (=H1864): An X-Ray Rich GRB Detected by HETE
  30. GRB 011121: J-band observations
  31. GRB 011121: NIR observations, host galaxy?
  32. GRB011121: UBRI Observations
  33. GRB 011121 J-Band Astrometry
  34. GRB 011121: Detection of Bright IR Counterpart
  35. GRB011121: possible redshift, continued decay
  36. GRB 011030: TNG K-band observation
  37. XRF011030: J and K band observations
  38. XRF011030: Chandra Observations
  39. GRB011030: Z-band observations
  40. GRB 011030 R band observations
  41. GRB 011030 I-band Observation
  42. The X-ray Flash 011030 ('GRB 011030')
  43. Non-triggered burst 011030 ("GRB 011030")
  44. The Radio Afterglow from the X-ray Rich GRB 011030
  45. GRB 010921: HST Detection of the Afterglow and Host Galaxy
  46. GRB 970828: HST Observations of the Host Galaxy
  47. GRB 000131: HST Detection of the Host Galaxy
  48. GRB 970828: HST Observations of the Host Galaxy
  49. Optical observation of SGR 1806-20 at the 6-m SAO telescope
  50. GRB011019: Subaru Optical Observations
  51. GRB 011030 I-band Observations
  52. GRB 011030 K-band Observations
  53. GRB010921, optical observations
  54. GRB011030 - further refinement WFC position
  55. GRB 011030, Radio observations
  56. GRB011030: radio search
  57. GRB 010921: Possible supernova component
  58. GRB010921, optical observation at early time
  59. GRB 010921, I-band observations
  60. GRB011019, optical observations
  61. GRB011019: A Faint, X-ray Rich GRB localized by HETE
  62. GRB 010921: The afterglow of HETE #1761
  63. Optical Observations of the field of HETE trigger #1793/GRB 011012?
  64. Optical Observations of the field of HETE trigger #1793/GRB 011012?
  65. GRB010923 as seen by BeppoSAX GRBM
  66. GRB010928(=H1770): Localization of a Long GRB by HETE
  67. GRB010923(=H1764): A Short Duration GRB Detected by HETE
  68. GRB010921, negative optical observations
  69. GRB010921 field photometry
  70. H1761: A Bright GRB Detected by HETE
  71. GRB000926, Host Galaxy Observations
  72. GRB001109, Host Galaxy Spectroscopic Observations
  73. Probable SGR or Short Duration GRB Detected by HETE
  74. GCN and HETE status
  75. Dramatic Increase in the Rate of X-ray Bursts Reported by HETE
  76. GRB 010222 - WHT BVRI images
  77. SGR1900+14 burst seen by HETE: BeppoSAX data
  78. GRB 010629 Optical Observations
  79. SGR1900+14: High Fluence Burst Localized by HETE
  80. GRB010629, optical observations
  81. GRB010629: A Burst Localized by HETE
  82. SGR1900+14: Second Burst Localized by HETE
  83. SGR1900+14: A Burst Localized by HETE
  84. SGR1806-20: A Second, Intense Burst Localized by HETE
  85. SGR1806-20: Localization by HETE
  86. HETE Fully-Automated GCN Notices
  87. GRB000301C: Late-time HST/STIS observation
  88. GRB010518: a faint BeppoSAX detection
  89. GRB000418: HST/STIS Second-epoch Observations
  90. X-ray precursors to the large flare from SGR 1900+14
  91. GRB010427, Gamma Ray Observations
  92. SGR 1900+14: No evidence of extended X-ray emission
  93. SGR 1900+14 : RXTE observations
  94. BeppoSAX/NFI Follow-up Observation of SGR 1900+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. SGR1900+14, I-band 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