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"

32828 results found.

  1. Second RXTE Observation of GRB 000115
  2. GRB991216, UBVRIJHK field photometry
  3. Single IPN error box for GRB991229
  4. GCN resumes full operations
  5. GRB 991216 VLBA Observations
  6. BEPPOSAX GRBM Localization of GRB991226
  7. IPN error boxes for GRB991229
  8. GRB 991216: J band spectrophotometry
  9. GRB 991216: Detection of the Host and/or Absorber Galaxy
  10. IPN localization of GRB991226
  11. Single IPN error box for GRB991221
  12. IPN error boxes for GRB991221
  13. GRB 991216 RXTE ASM Observations
  14. IPN error box for GRB991216
  15. GRB 991216: Updated BATSE parameters
  16. Lowell/Perkins observation of GRB 991216
  17. GRB 991217 (SAX J2303.2+0015) Optical observations
  18. Chandra observation of the X-ray afterglow of GRB991216
  19. GRB 991216, optical observations
  20. GRB 991216 Optical Observations
  21. GRB 991216 Optical spectroscopy/imaging
  22. K observations of GRB991216
  23. GRB 991217 (SAX J2303.2+0015) Optical observations
  24. GRB991216 Spectroscopy
  25. Lowell/Perkins observation of GRB 991216
  26. GRB991216, optical observations
  27. Refined IPN localization of GRB991216
  28. GRB 991216 Radio Observations
  29. GRB 991217
  30. GRB 991208 Keck Spectroscopy
  31. GRB 991208 Infrared Detection
  32. GRB 991216--Summary of RXTE Observations
  33. GRB 991216 Optical Observations
  34. GRB 991216, optical observations
  35. GRB 991208 SAO-RAS Spectroscopy
  36. SAX J2303.2+0015: an x-ray/GRB?
  37. GRB 991216, Optical Transient
  38. GRB 991216, Optical Afterglow
  39. GRB 991216: Comparison with DPOSS images
  40. GRB 991208 optical observations
  41. Lowell/Perkins observation of GRB 991216
  42. GRB 991216 Optical Observation
  43. GRB 991208 Keck Spectroscopy
  44. GRB 991216: Extremely bright BATSE burst
  45. GRB991208, optical observations
  46. GRB 991208 Keck Spectroscopy
  47. GRB991208 - millimeter detection
  48. GRB 991208, Optical Observation
  49. GRB 991208 - OVRO detection
  50. GRB 991208 Optical Decay
  51. GRB 991208 optical observations
  52. GRB 991208 optical observations
  53. GRB 991208: Radio Observations
  54. IPN localization of GRB991208
  55. Optical Observations of GRB991105
  56. GRB991106: BeppoSAX/BATSE results
  57. GRB 991106, optical observations
  58. GRB991106, near-infrared observations
  59. BeppoSAX NFI Observation of GRB991106
  60. GRB 991106, radio observations
  61. GRB991106: the first BeppoSAX short GRB detection?
  62. GRB 991105: BATSE Observations
  63. IPN localization of GRB991105
  64. GRB 991106 Optical Observations
  65. GRB 991105, optical observations
  66. GRB991106, optical observation at SAO-RAS
  67. GRB 991106, LOTIS Optical Observations
  68. GRB 991106, optical observations
  69. BeppoSAX GRB Alert: GRB991106
  70. BeppoSAX MAIL n. 99/30: GRB991105 refined position (fwd)
  71. GRB ALERT: GRB991105
  72. GRB 991014 - X-ray afterglow identification by BeppoSAX-NFI
  73. GRB 991014, Optical Observations
  74. GRB 991014 - BeppoSAX NFI observations
  75. GRB 991014, Optical Observations
  76. GRB 991014, radio observations
  77. GRB991014 BATSE Observations
  78. GRB 991014, Optical Observations
  79. GRB 991014, optical observations
  80. Super-LOTIS optical observation of GRB991014
  81. IPN/NFI error box for GRB991014
  82. IPN localization of GRB991014 - CORRECTION
  83. IPN localization of GRB991014
  84. BeppoSAX ALERT: GRB991014
  85. GRB 990915 optical observations
  86. GRB 990907 optical observations
  87. BATSE GRB trigger criteria
  88. Optical Observations of GRB990907
  89. IPN error box for GRB990915 (=BATSE 7766)
  90. IPN localization of BATSE #7766 (GRB990915)
  91. IPN localization of GRB990907
  92. GRB990908, another BeppoSAX-GRBM/WFC burst detection
  93. BeppoSAX MAIL n. 99/24: GRB ALERT: GRB990907
  94. GRB 990712 Late Optical Decay and Host Galaxy
  95. GRB 990712, Optical Observation
  96. GRB990806: BATSE Observations
  97. GRB 990806 Optical observations
  98. Optical Observations of GRB990806
  99. GRB 990806, Optical Observations
  100. GRB 990806, optical observations

Advanced

Download all Circulars as a .tar.gz archive:
Looking for U.S. government information and services? Visit USA.gov