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"

232 results found.

  1. GRB040827 optical observations
  2. GRB040825B, BVRcIc field photometry
  3. GRB040825A, BVRcIc field photometry
  4. GRB040825B: Correction to GCN 2657
  5. GRB040422, BVRcIc field calibration
  6. INTEGRAL-SPI/ACS GRB data: timing correction
  7. GRB030913, candidate afterglow observations
  8. GRB030913: AAVSO optical observations
  9. XRF030723, BVRcIc field photometry update
  10. GRB030725, optical transient observations
  11. GRB030725, possible optical transient
  12. XRF030723, BVRcIc field photometry correction
  13. XRF030723, BVRcIc field photometry
  14. GRB030723, optical observations
  15. GRB030528, BVRI field photometry
  16. GRB030418, BVRcIc field photometry
  17. GRB030429, BVRcIc field photometry
  18. GRB030429, possible optical counterpart
  19. GRB030329, optical position
  20. GRB030328, UBVRcIc field photometry
  21. GRB030329, fading resumes
  22. GRB030329, cessation of fading
  23. GRB030329, new UBVRcIc field photometry
  24. GRB030329, BVRcIc field photometry
  25. GRB030131, BVRcIc field photometry
  26. GRB030324, BVRcIc field photometry
  27. GRB030323, possible optical counterpart
  28. GRB030323, BVRcIc field calibration
  29. GRB030227, BVRcIc field photometry
  30. GRB030226, BVRcIc field calibration
  31. GRB030204 field photometry
  32. GRB030115, afterglow candidate
  33. GRB021219, optical observations
  34. GRB021211, BVRI field photometry
  35. GRB021201, BVRcIc field photometry
  36. GRB021113, SPI ACS observation
  37. GRB021112, BVRI field photometry
  38. GRB021016, optical observations
  39. GRB021004, UBVRcIc field photometry update
  40. GRB021004, astrometric position
  41. GRB021004, Optical Observations
  42. GRB021004, BVRcIc field photometry
  43. XRF020903, BVRI field photometry
  44. GRB020812: negative optical observations
  45. GRB020813, UBVRI field calibration
  46. GRB020813, optical observations
  47. GRB020813, astrometric position
  48. GRB020801, optical afterglow candidate
  49. GRB020604, optical observations
  50. GRB020604, BVRcIc field photometry
  51. GRB020603, BVRcIc field observations
  52. GRB020531, BVRcIc field photometry
  53. GRB020531, optical observations
  54. GRB020525, optical observations
  55. GRB020406(?), optical observations
  56. GRB020410, optical observations
  57. GRB020406(?), optical observations
  58. GRB020331 field photometry
  59. GRB020317 BVRI field photometry
  60. GRB011211 revised BVRI field photometry
  61. GRB020305 BVRI field photometry
  62. GRB020322 BVRI field photometry
  63. GRB020321 optical observations
  64. GRB020124 BVRI field photometry
  65. SN2002ap (SN/GRB?) UBVRI Field Photometry
  66. GRB011212, BVRI field photometry
  67. GRB011211, BVRI field photometry
  68. GRB011130 (XRF011130) optical observations
  69. GRB011019, optical observations -- correction
  70. GRB011019, optical observations
  71. GRB010921, negative optical observations
  72. GRB010921 field photometry
  73. GRB010629, optical observations
  74. GRB010412, field photometry
  75. GRB010324, revised field photometry
  76. GRB010324, field photometry
  77. GRB010326B, field photometry
  78. GRB010326, field photometry
  79. GRB010220, field photometry
  80. GRB010324, optical observations
  81. GRB 010222, Optical Observations
  82. GRB010214, field photometry
  83. GRB010222, field photometry
  84. GRB010222, optical observations
  85. GRB010222
  86. GRB010222
  87. GRB010213, Near-IR observations
  88. GRB 010119, optical observations
  89. GRB010103, optical observations
  90. GRB001120, optical observations
  91. GRB001105 BVRI field photometry correction
  92. GRB001105, BVRI field photometry
  93. GRB001019, Optical Observations
  94. GRB 000911, BVRI field photometry
  95. GRB000830, BVRI field photometry
  96. GRB 000727, optical observations
  97. GRB000630, Revised BVRI Field Photometry
  98. GRB000630, BVRI Field Photometry
  99. GRB000519, BVRI field photometry
  100. GRB000508B, BVR field photometry

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