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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. Optical Observations of GRB991105
  2. GRB991106: BeppoSAX/BATSE results
  3. GRB 991106, optical observations
  4. GRB991106, near-infrared observations
  5. BeppoSAX NFI Observation of GRB991106
  6. GRB 991106, radio observations
  7. GRB991106: the first BeppoSAX short GRB detection?
  8. GRB 991105: BATSE Observations
  9. IPN localization of GRB991105
  10. GRB 991106 Optical Observations
  11. GRB 991105, optical observations
  12. GRB991106, optical observation at SAO-RAS
  13. GRB 991106, LOTIS Optical Observations
  14. GRB 991106, optical observations
  15. BeppoSAX refined position for GRB991106
  16. BeppoSAX GRB Alert: GRB991106
  17. Revised BeppoSAX WFC position of GRB991105
  18. GRB991105: SAX-GRBM/-WFC detection
  19. BeppoSAX MAIL n. 99/30: GRB991105 refined position (fwd)
  20. GRB ALERT: GRB991105
  21. GRB 991014 - X-ray afterglow identification by BeppoSAX-NFI
  22. GRB 991014, Optical Observations
  23. GRB 991014 - BeppoSAX NFI observations
  24. GRB 991014, Optical Observations
  25. GRB 991014, radio observations
  26. GRB991014 BATSE Observations
  27. GRB 991014, Optical Observations
  28. GRB 991014, optical observations
  29. Super-LOTIS optical observation of GRB991014
  30. IPN/NFI error box for GRB991014
  31. IPN localization of GRB991014 - CORRECTION
  32. IPN localization of GRB991014
  33. BeppoSAX ALERT: GRB991014
  34. GRB 990915 optical observations
  35. GRB 990907 optical observations
  36. BATSE GRB trigger criteria
  37. Optical Observations of GRB990907
  38. IPN error box for GRB990915 (=BATSE 7766)
  39. IPN localization of BATSE #7766 (GRB990915)
  40. GRB990907: BeppoSAX follow up and X-ray afterglow
  41. GRB990907 and 990908
  42. IPN localization of GRB990907
  43. GRB990908, another BeppoSAX-GRBM/WFC burst detection
  44. GRB990907: refined WFC position
  45. BeppoSAX MAIL n. 99/24: GRB ALERT: GRB990907
  46. GRB 990712 Late Optical Decay and Host Galaxy
  47. GRB 990712, Optical Observation
  48. GRB990806 BeppoSAX follow up
  49. GRB990806: BATSE Observations
  50. GRB 990806 Optical observations
  51. Optical Observations of GRB990806
  52. GRB 990806, Optical Observations
  53. GRB 990806, optical observations
  54. GRB 990806, Optical Observations
  55. GRB990806 UBVRIJHK observations
  56. GRB990806: possible X-ray afterglow, BeppoSAX
  57. BeppoSAX ALERT GRB990806: Summer GRB
  58. GRB 990712 Optical Observations
  59. GRB990705: No Evidence for Neutrino Signal
  60. GRB 990712 Optical Decay: Indication of Bright Host Galaxy
  61. VLT spectrum of GRB990712
  62. GRB 990712
  63. Late-time HST/STIS Observations of GRB 990510
  64. Refined BeppoSAX-WFC position of GRB990712
  65. BeppoSAX NFI Observation of GRB990705
  66. BeppoSAX NFI Observation of GRB990705
  67. Updated Astrometry for the IR Counterpart of GRB990705
  68. GRB 990705, R-band observations
  69. Updated IPN localization of GRB990705
  70. IPN localization of GRB990704
  71. IPN localization of GRB990705
  72. Infrared and Optical Observations of GRB990705
  73. GRB 990705, radio observations
  74. GRB990704: SAX-NFI results summary
  75. GRB990704 radio and optical observations
  76. BeppoSAX GRB990705: possible X-ray afterglow
  77. GRB 990704 X-ray Observations
  78. GRB 990704 Optical Observations
  79. GRB 990704, optical observations
  80. GRB990704
  81. GRB990705: Intriguing Positional Coincidences
  82. GRB990704
  83. Refined BeppoSAX-WFC position of GRB990704: Errata Corrige
  84. GRB990704, optical observations
  85. GRB990704: possible X-ray afterglow
  86. Identification of a possible optical counterpart for GRB990704
  87. GRB990704
  88. Refined BeppoSAX-WFC position of GRB990704
  89. GRB990704: BeppoSAX detection
  90. BeppoSAX NFI Observation of GRB990627 X-ray afterglow
  91. Optical Observations of GRB990627
  92. GRB 990627, radio observations
  93. GRB990627: BeppoSAX-WFC final location
  94. BeppoSAX: GRB990625
  95. Late-time HST/STIS Observation of GRB 990123
  96. GRB 990506 - clarification to GCN 352
  97. GRB 990506 - Optical Observations
  98. Optical Observations of GRB 990506
  99. GRB 990506 Radio Transient
  100. GRB990527 Optical Observations

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