Skip to main content
Updates to LVK & CHIME Notices, Schema v7.2.3! 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"

32504 results found.

  1. GRB000210, Radio Observations
  2. Correction to GCN 557 (GRB000214: BeppoSAX GRBM and WFC Detection)
  3. IPN annulus for GRB000214
  4. Optical observations of GRB000210
  5. GRB000210 X-ray afterglow
  6. GRB 000210: BATSE Observations
  7. Correction to Chandra Position of GRB000210 afterglow
  8. Optical observations of the Chandra X-ray source for GRB000210
  9. GRB000210, Radio Observations
  10. Optical candidate for GRB000210
  11. Chandra Observations of GRB000210 X-ray Afterglow
  12. IPN triangulation of GRB000210
  13. GRB000201, Radio Observations
  14. Optical observations of GRB000131
  15. GRB000201 Optical Observations
  16. GRB 000131 Optical Observations
  17. GRB000126 Optical Observations
  18. GRB 991208, radio observations
  19. BATSE+IPN location of GRB000131
  20. GRB 000126, optical observations
  21. GRB000126, optical observations
  22. BATSE location of GRB000126
  23. GRB 000115 Optical observations
  24. BATSE Observations of GRB000115
  25. Correction to GCN 520 (IPN annulus for GRB000115)
  26. IPN annulus for GRB000115
  27. GRB991216, UBVRIJHK field photometry
  28. GRB991216 late optical observation
  29. Single IPN error box for GRB991229
  30. GCN resumes full operations
  31. GRB 991216 VLBA Observations
  32. BEPPOSAX GRBM Localization of GRB991226
  33. GRB 991216: J band spectrophotometry
  34. GRB 991216: Detection of the Host and/or Absorber Galaxy
  35. Single IPN error box for GRB991221
  36. GRB 991216 RXTE ASM Observations
  37. IPN error box for GRB991216
  38. Lowell/Perkins observation of GRB 991216
  39. GRB 991217 (SAX J2303.2+0015) Optical observations
  40. GRB991217/SAX J2303.2+0015, optical observations
  41. Chandra observation of the X-ray afterglow of GRB991216
  42. GRB 991216, optical observations
  43. GRB 991216 Optical Observations
  44. GRB 991216 Optical spectroscopy/imaging
  45. VLT spectra of GRB991216
  46. GRB991216 Optical and IR observations
  47. SAX J2303.2+0015 Optical observations
  48. IR observations of GRB991216
  49. GRB991216 radio observations
  50. GRB 991217 (SAX J2303.2+0015) Optical observations
  51. GRB991216 radio observations
  52. Lowell/Perkins observation of GRB 991216
  53. GRB991216, optical observations
  54. Refined IPN localization of GRB991216
  55. GRB 991216 Radio Observations
  56. GRB 991208 Keck Spectroscopy
  57. GRB 991208 Infrared Detection
  58. GRB991216
  59. GRB 991216--Summary of RXTE Observations
  60. GRB 991216 Optical Observations
  61. GRB 991216, optical observations
  62. GRB 991208 SAO-RAS Spectroscopy
  63. GRB 991216, Optical Transient
  64. GRB 991216, Optical Afterglow
  65. GRB991216 ('Beethoven Burst') B, R, and K Observations
  66. GRB 991216: Comparison with DPOSS images
  67. GRB 991208 optical observations
  68. Lowell/Perkins observation of GRB 991216
  69. GRB 991216 Optical Observation
  70. GRB 991208 Keck Spectroscopy
  71. R-band Observations of GRB991208 at TNG
  72. GRB991208, optical observations
  73. GRB 991208 Keck Spectroscopy
  74. GRB991208 - millimeter detection
  75. GRB 991208, Optical Observation
  76. GRB991208 15-GHz observations
  77. GRB991208, optical observations
  78. GRB 991208 - OVRO detection
  79. GRB 991208 Optical Decay
  80. GRB 991208 optical observations
  81. GRB 991208 optical observations
  82. GRB 991208: Radio Observations
  83. Optical Observations of GRB991105
  84. GRB991106: BeppoSAX/BATSE results
  85. GRB 991106, optical observations
  86. GRB991106, near-infrared observations
  87. BeppoSAX NFI Observation of GRB991106
  88. GRB 991106, radio observations
  89. GRB 991105: BATSE Observations
  90. IPN localization of GRB991105
  91. GRB 991106 Optical Observations
  92. GRB 991105, optical observations
  93. GRB991106, optical observation at SAO-RAS
  94. GRB 991106, LOTIS Optical Observations
  95. GRB 991106, optical observations
  96. Revised BeppoSAX WFC position of GRB991105
  97. GRB 991014 - X-ray afterglow identification by BeppoSAX-NFI
  98. GRB 991014, Optical Observations
  99. GRB 991014 - BeppoSAX NFI observations
  100. GRB 991014, Optical Observations

Advanced

Download all Circulars as a .tar.gz archive (updated once a day):
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