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"

36135 results found.

  1. GRB 990712 Late Optical Decay and Host Galaxy
  2. GRB 990712, Optical Observation
  3. GRB990806: BATSE Observations
  4. GRB 990806 Optical observations
  5. Optical Observations of GRB990806
  6. GRB 990806, Optical Observations
  7. GRB 990806, optical observations
  8. GRB 990806, Optical Observations
  9. GRB990806 UBVRIJHK observations
  10. BeppoSAX ALERT GRB990806: Summer GRB
  11. GRB 990712 Optical Observations
  12. GRB990705: No Evidence for Neutrino Signal
  13. GRB 990712 Optical Decay: Indication of Bright Host Galaxy
  14. VLT spectrum of GRB990712
  15. GRB 990712
  16. Late-time HST/STIS Observations of GRB 990510
  17. Refined BeppoSAX-WFC position of GRB990712
  18. GRB 990705, R-band observations
  19. Updated IPN localization of GRB990705
  20. IPN localization of GRB990704
  21. IPN localization of GRB990705
  22. Infrared and Optical Observations of GRB990705
  23. GRB 990705, radio observations
  24. GRB990704 radio and optical observations
  25. GRB 990704 X-ray Observations
  26. GRB 990704 Optical Observations
  27. GRB 990704, optical observations
  28. GRB990704
  29. GRB990705: Intriguing Positional Coincidences
  30. GRB990704
  31. GRB990704, optical observations
  32. Identification of a possible optical counterpart for GRB990704
  33. GRB990704
  34. Refined BeppoSAX-WFC position of GRB990704
  35. GRB990704: BeppoSAX detection
  36. Optical Observations of GRB990627
  37. GRB 990627, radio observations
  38. GRB990627: BeppoSAX-WFC final location
  39. BeppoSAX: GRB990625
  40. Late-time HST/STIS Observation of GRB 990123
  41. GRB 990506 - clarification to GCN 352
  42. GRB 990506 - Optical Observations
  43. Optical Observations of GRB 990506
  44. GRB 990506 Radio Transient
  45. GRB990527 Optical Observations
  46. X-ray/GRB 1SAX J0835.9+5118, Optical Observation
  47. IPN error box for GRB990527
  48. Late Afterglows of GRBs 990510, 990123
  49. X-ray/GRB 1SAX J0835.9+5118, TNG V and R observations
  50. X-ray/GRB 1SAX J0835.9+5118, BATSE Observation
  51. X-ray/GRB 1SAX J0835.9+5118, Optical Observations
  52. GRB 990506 optical observation
  53. X-ray/GRB 1SAX J0835.9+5118, Optical Observation
  54. X-ray/GRB 1SAX J0835.9+5118, Optical Observation
  55. X-ray/GRB 1SAX J0835.9+5118, Optical Observation
  56. X-ray/GRB 1SAX J0835.9+5118, Optical Observation
  57. radio observations of X-ray/GRB transient field
  58. optical observation of the X-ray/GRB transient SAX J0835.9+5118
  59. Optical report on X-ray/GRB transient
  60. radio detection of X-ray/GRB transient
  61. BeppoSAX: A new fast X-ray transient
  62. GRB 990510: optical observations
  63. GRB990510: photometric and spectroscopic observations with the VLT
  64. GRB 990510: optical linear polarization
  65. GRB 990510: optical observations
  66. GRB990510, VI observations
  67. GRB 990506 R band observations
  68. GRB990510: X-ray afterglow
  69. GRB 990510: optical observation
  70. VLT spectrum of GRB990510
  71. GRB 990510: Broad Band Break
  72. GRB 990510: BATSE Observations
  73. GRB 990510 Optical Observations
  74. GRB 990510, BVI photometry
  75. GRB 990510 optical observations
  76. GRB 990510: BeppoSAX/GRBM observations
  77. GRB990510 optical observations
  78. GRB 990510 optical observations
  79. GRB 990510 optical observations
  80. Galactic extinction towards GRB 990510
  81. GRB 990510 optical observations
  82. IPN localization of GRB990510
  83. GRB 990506 Radio Observations
  84. GRB 990123, optical monitoring
  85. GRB 990506: BATSE Observations
  86. GRB 990506, optical observations
  87. GRB 990510: Final BeppoSAX-WFC Coordinates
  88. GRB 990506, Optical Observations
  89. GRB 990506 optical observations
  90. GRB 990506 optical observations
  91. GRB 990506, optical observations
  92. GRB990506 observation plan
  93. Refined IPN error box for GRB990506
  94. GRB 990506: Limits on the possible optical transient
  95. GRB 990506, armchair astronomy
  96. GRB 990506, optical observations from +1 to +3 hours
  97. GRB 990506, optical observations
  98. GRB990506 observation plan
  99. New IPN/RXTE error box for GRB990506
  100. IPN localization for GRB990506

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