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"
  1. SGR1900+14
  2. SGR 1900+14: Correction to GCN 1049
  3. GRB 010222 /corrections to VBT data
  4. Millimeter observation of SGR 1900+14
  5. SGR 1900+14: Detection of extended X-ray emission
  6. Chandra Observations of SGR 1900+14
  7. SGR 1900+14, Chandra observations
  8. Chandra Observations of SGR 1900+14
  9. Possible precursor to the SGR1900+14 giant burst
  10. SGR1900+14, I-band observations
  11. IPN Triangulation of the Giant Flare from SGR1900+14
  12. GRB010412, field photometry
  13. Giant flare from SGR1900+14
  14. GRB 010326b Optical Observations
  15. GRB010412: Optical observations
  16. GRB010412: Optical observations
  17. GRB010412: BeppoSAX GRBM and WFC observations
  18. IPN Triangulation of GRB010412
  19. GRB010412: refined positions from BeppoSAX
  20. BeppoSAX GRB: extension of BSAX operations upto April 30, 2002
  21. BeppoSAX GRB ALERT: GRB010412
  22. GRB Observation Report
  23. GRB010324, revised field photometry
  24. REVISED LOCATION OF GRB010326A
  25. GRB 980326: Late-time HST/STIS observations
  26. GRB010324, field photometry
  27. GRB010326B, field photometry
  28. GRB010326, field photometry
  29. GRB010220, field photometry
  30. Further Optical Observations of GRB 010324
  31. GRB010222, CXO X-ray observations
  32. GRB 010326A: Further optical observations
  33. GRB010324: BeppoSAX/GRBM data
  34. GRB 010326B: Optical observations
  35. GRB010324, optical observations
  36. GRB010326B: Localization by HETE (2nd GRB for this date)
  37. GRB 010326: Optical observations
  38. GRB 010326 optical observations
  39. GRB010326: Refined Localization by HETE
  40. GRB010326: Localization by HETE
  41. Duration, ECT, peak flux and fluence of GRB010324
  42. Optical Observations of GRB 010324
  43. IPN TRIANGULATION OF GRB010324
  44. GRB990705, VLT-FORS1 observations of the host galaxy
  45. GRB010222, late-time optical observation
  46. Support extension to the BeppoSAX mission
  47. GRB 010222 - HEGRA GeV/TeV Observations
  48. Congratulate Scott on the 1000th GRB Coordinates Network Circular!
  49. GRB010222: Chandra X-ray Observatory Observation
  50. GRB010222: Sub-millimeter vanishing act
  51. GRB010222 - Optical observation
  52. GRB 010222, Optical Observations
  53. GRB010220 optical obsercations
  54. GRB010222 - Optical observation
  55. GRB 010222: High-Resolution Keck Spectroscopy
  56. GRB010222: Optical observation and decay
  57. GRB 010214, I-band data
  58. Sub-millimeter Excess/GRB 010222
  59. GRB 010222
  60. GRB 010222 HST/Chandra TOO
  61. GRB 010222
  62. GRB010222 further R-band photometry
  63. GRB010222: R-band data
  64. GRB010222 Optical observations
  65. GRB 010222: Keck Spectroscopy
  66. GRB010214, field photometry
  67. GRB010222, field photometry
  68. GRB010222 further R-band photometry
  69. GRB010222, possible increase of optical decay slope
  70. GRB 010222 Kyoto optical observation
  71. GRB010222: fading behavior
  72. GRB 010222 BV optical observations
  73. GRB010220, Optical Observations
  74. GRB010222 R-BAND OBSERVATION
  75. GRB 010220: Near-IR Observations
  76. GRB010214 follow-up from Hanle
  77. GRB 010222: Near-IR Observations
  78. GRB 010222: Optical Observations
  79. GRB 010222, Decay Slope Confirmed
  80. GRB010222: Another absorption line system
  81. GRB010222: Optical decay slope
  82. GRB 010214, Optical Observations
  83. GRB010222: Sub-millimeter detection
  84. GRB010222: R-band fading behavior
  85. GRB010222: Optical Observations
  86. GRB010222, radio observations
  87. GRB010222, optical observations
  88. GRB010222: BeppoSAX/NFI Observations
  89. Redshift of the Optical Transient of GRB010222
  90. GRB010214B,Gamma Ray Observations
  91. GRB010222: possible optical counterpart
  92. GRB010222
  93. GRB010222
  94. GRB010222: BeppoSAX refined position
  95. ALERT: GRB010222: the brightest GRB observed by BeppoSAX
  96. GRB010220, Radio and Optical Observations
  97. GRB 010220, simultaneous optical observations
  98. GRB010220: BeppoSAX WFC and GRBM preliminary data
  99. GRB010214, candidate optical afterglow
  100. GRB010214, 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