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

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