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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. GRB991208 15-GHz observations
  2. GRB991208, optical observations
  3. GRB 991208 - OVRO detection
  4. GRB 991208 Optical Decay
  5. GRB 991208 optical observations
  6. GRB 991208 optical observations
  7. GRB 991208: Radio Observations
  8. IPN localization of GRB991208
  9. Optical Observations of GRB991105
  10. GRB991106: BeppoSAX/BATSE results
  11. GRB 991106, optical observations
  12. GRB991106, near-infrared observations
  13. BeppoSAX NFI Observation of GRB991106
  14. GRB 991106, radio observations
  15. GRB991106: the first BeppoSAX short GRB detection?
  16. GRB 991105: BATSE Observations
  17. IPN localization of GRB991105
  18. GRB 991106 Optical Observations
  19. GRB 991105, optical observations
  20. GRB991106, optical observation at SAO-RAS
  21. GRB 991106, LOTIS Optical Observations
  22. GRB 991106, optical observations
  23. BeppoSAX refined position for GRB991106
  24. BeppoSAX GRB Alert: GRB991106
  25. Revised BeppoSAX WFC position of GRB991105
  26. GRB991105: SAX-GRBM/-WFC detection
  27. BeppoSAX MAIL n. 99/30: GRB991105 refined position (fwd)
  28. GRB ALERT: GRB991105
  29. GRB 991014 - X-ray afterglow identification by BeppoSAX-NFI
  30. GRB 991014, Optical Observations
  31. GRB 991014 - BeppoSAX NFI observations
  32. GRB 991014, Optical Observations
  33. GRB 991014, radio observations
  34. GRB991014 BATSE Observations
  35. GRB 991014, Optical Observations
  36. GRB 991014, optical observations
  37. Super-LOTIS optical observation of GRB991014
  38. IPN/NFI error box for GRB991014
  39. IPN localization of GRB991014 - CORRECTION
  40. IPN localization of GRB991014
  41. BeppoSAX ALERT: GRB991014
  42. GRB 990915 optical observations
  43. GRB 990907 optical observations
  44. BATSE GRB trigger criteria
  45. Optical Observations of GRB990907
  46. IPN error box for GRB990915 (=BATSE 7766)
  47. IPN localization of BATSE #7766 (GRB990915)
  48. GRB990907: BeppoSAX follow up and X-ray afterglow
  49. GRB990907 and 990908
  50. IPN localization of GRB990907
  51. GRB990908, another BeppoSAX-GRBM/WFC burst detection
  52. GRB990907: refined WFC position
  53. BeppoSAX MAIL n. 99/24: GRB ALERT: GRB990907
  54. GRB 990712 Late Optical Decay and Host Galaxy
  55. GRB 990712, Optical Observation
  56. GRB990806 BeppoSAX follow up
  57. GRB990806: BATSE Observations
  58. GRB 990806 Optical observations
  59. Optical Observations of GRB990806
  60. GRB 990806, Optical Observations
  61. GRB 990806, optical observations
  62. GRB 990806, Optical Observations
  63. GRB990806 UBVRIJHK observations
  64. GRB990806: possible X-ray afterglow, BeppoSAX
  65. BeppoSAX ALERT GRB990806: Summer GRB
  66. GRB 990712 Optical Observations
  67. GRB990705: No Evidence for Neutrino Signal
  68. GRB 990712 Optical Decay: Indication of Bright Host Galaxy
  69. VLT spectrum of GRB990712
  70. GRB 990712
  71. Late-time HST/STIS Observations of GRB 990510
  72. Refined BeppoSAX-WFC position of GRB990712
  73. BeppoSAX NFI Observation of GRB990705
  74. BeppoSAX NFI Observation of GRB990705
  75. Updated Astrometry for the IR Counterpart of GRB990705
  76. GRB 990705, R-band observations
  77. Updated IPN localization of GRB990705
  78. IPN localization of GRB990704
  79. IPN localization of GRB990705
  80. Infrared and Optical Observations of GRB990705
  81. GRB 990705, radio observations
  82. GRB990704: SAX-NFI results summary
  83. GRB990704 radio and optical observations
  84. BeppoSAX GRB990705: possible X-ray afterglow
  85. GRB 990704 X-ray Observations
  86. GRB 990704 Optical Observations
  87. GRB 990704, optical observations
  88. GRB990704
  89. GRB990705: Intriguing Positional Coincidences
  90. GRB990704
  91. Refined BeppoSAX-WFC position of GRB990704: Errata Corrige
  92. GRB990704, optical observations
  93. GRB990704: possible X-ray afterglow
  94. Identification of a possible optical counterpart for GRB990704
  95. GRB990704
  96. Refined BeppoSAX-WFC position of GRB990704
  97. GRB990704: BeppoSAX detection
  98. BeppoSAX NFI Observation of GRB990627 X-ray afterglow
  99. Optical Observations of GRB990627
  100. GRB 990627, radio observations

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