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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. GRB991216 ('Beethoven Burst') B, R, and K Observations
  2. GRB 991216: Comparison with DPOSS images
  3. GRB991216, infrared observations
  4. GRB991216 Optical Observations
  5. GRB 991208 optical observations
  6. Lowell/Perkins observation of GRB 991216
  7. GRB 991216 Optical Observation
  8. GRB 991208 Keck Spectroscopy
  9. GRB 991216: Extremely bright BATSE burst
  10. R-band Observations of GRB991208 at TNG
  11. GRB991208, optical observations
  12. GRB 991208 Keck Spectroscopy
  13. GRB991208 - millimeter detection
  14. GRB 991208, Optical Observation
  15. GRB991208 15-GHz observations
  16. GRB991208, optical observations
  17. GRB 991208 - OVRO detection
  18. GRB 991208 Optical Decay
  19. GRB 991208 optical observations
  20. GRB 991208 optical observations
  21. GRB 991208: Radio Observations
  22. IPN localization of GRB991208
  23. Optical Observations of GRB991105
  24. GRB991106: BeppoSAX/BATSE results
  25. GRB 991106, optical observations
  26. GRB991106, near-infrared observations
  27. BeppoSAX NFI Observation of GRB991106
  28. GRB 991106, radio observations
  29. GRB991106: the first BeppoSAX short GRB detection?
  30. GRB 991105: BATSE Observations
  31. IPN localization of GRB991105
  32. GRB 991106 Optical Observations
  33. GRB 991105, optical observations
  34. GRB991106, optical observation at SAO-RAS
  35. GRB 991106, LOTIS Optical Observations
  36. GRB 991106, optical observations
  37. BeppoSAX refined position for GRB991106
  38. BeppoSAX GRB Alert: GRB991106
  39. Revised BeppoSAX WFC position of GRB991105
  40. GRB991105: SAX-GRBM/-WFC detection
  41. BeppoSAX MAIL n. 99/30: GRB991105 refined position (fwd)
  42. GRB ALERT: GRB991105
  43. GRB 991014 - X-ray afterglow identification by BeppoSAX-NFI
  44. GRB 991014, Optical Observations
  45. GRB 991014 - BeppoSAX NFI observations
  46. GRB 991014, Optical Observations
  47. GRB 991014, radio observations
  48. GRB991014 BATSE Observations
  49. GRB 991014, Optical Observations
  50. GRB 991014, optical observations
  51. Super-LOTIS optical observation of GRB991014
  52. IPN/NFI error box for GRB991014
  53. IPN localization of GRB991014 - CORRECTION
  54. IPN localization of GRB991014
  55. BeppoSAX ALERT: GRB991014
  56. GRB 990915 optical observations
  57. GRB 990907 optical observations
  58. BATSE GRB trigger criteria
  59. Optical Observations of GRB990907
  60. IPN error box for GRB990915 (=BATSE 7766)
  61. IPN localization of BATSE #7766 (GRB990915)
  62. GRB990907: BeppoSAX follow up and X-ray afterglow
  63. GRB990907 and 990908
  64. IPN localization of GRB990907
  65. GRB990908, another BeppoSAX-GRBM/WFC burst detection
  66. GRB990907: refined WFC position
  67. BeppoSAX MAIL n. 99/24: GRB ALERT: GRB990907
  68. GRB 990712 Late Optical Decay and Host Galaxy
  69. GRB 990712, Optical Observation
  70. GRB990806 BeppoSAX follow up
  71. GRB990806: BATSE Observations
  72. GRB 990806 Optical observations
  73. Optical Observations of GRB990806
  74. GRB 990806, Optical Observations
  75. GRB 990806, optical observations
  76. GRB 990806, Optical Observations
  77. GRB990806 UBVRIJHK observations
  78. GRB990806: possible X-ray afterglow, BeppoSAX
  79. BeppoSAX ALERT GRB990806: Summer GRB
  80. GRB 990712 Optical Observations
  81. GRB990705: No Evidence for Neutrino Signal
  82. GRB 990712 Optical Decay: Indication of Bright Host Galaxy
  83. VLT spectrum of GRB990712
  84. GRB 990712
  85. Late-time HST/STIS Observations of GRB 990510
  86. Refined BeppoSAX-WFC position of GRB990712
  87. BeppoSAX NFI Observation of GRB990705
  88. BeppoSAX NFI Observation of GRB990705
  89. Updated Astrometry for the IR Counterpart of GRB990705
  90. GRB 990705, R-band observations
  91. Updated IPN localization of GRB990705
  92. IPN localization of GRB990704
  93. IPN localization of GRB990705
  94. Infrared and Optical Observations of GRB990705
  95. GRB 990705, radio observations
  96. GRB990704: SAX-NFI results summary
  97. GRB990704 radio and optical observations
  98. BeppoSAX GRB990705: possible X-ray afterglow
  99. GRB 990704 X-ray Observations
  100. GRB 990704 Optical Observations

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