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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"

35264 results found.

  1. GRB 991106 Optical Observations
  2. GRB 991105, optical observations
  3. GRB991106, optical observation at SAO-RAS
  4. GRB 991106, LOTIS Optical Observations
  5. GRB 991106, optical observations
  6. BeppoSAX GRB Alert: GRB991106
  7. BeppoSAX MAIL n. 99/30: GRB991105 refined position (fwd)
  8. GRB ALERT: GRB991105
  9. GRB 991014 - X-ray afterglow identification by BeppoSAX-NFI
  10. GRB 991014, Optical Observations
  11. GRB 991014 - BeppoSAX NFI observations
  12. GRB 991014, Optical Observations
  13. GRB 991014, radio observations
  14. GRB991014 BATSE Observations
  15. GRB 991014, Optical Observations
  16. GRB 991014, optical observations
  17. Super-LOTIS optical observation of GRB991014
  18. IPN/NFI error box for GRB991014
  19. IPN localization of GRB991014 - CORRECTION
  20. IPN localization of GRB991014
  21. BeppoSAX ALERT: GRB991014
  22. GRB 990915 optical observations
  23. GRB 990907 optical observations
  24. BATSE GRB trigger criteria
  25. Optical Observations of GRB990907
  26. IPN error box for GRB990915 (=BATSE 7766)
  27. IPN localization of BATSE #7766 (GRB990915)
  28. IPN localization of GRB990907
  29. GRB990908, another BeppoSAX-GRBM/WFC burst detection
  30. BeppoSAX MAIL n. 99/24: GRB ALERT: GRB990907
  31. GRB 990712 Late Optical Decay and Host Galaxy
  32. GRB 990712, Optical Observation
  33. GRB990806: BATSE Observations
  34. GRB 990806 Optical observations
  35. Optical Observations of GRB990806
  36. GRB 990806, Optical Observations
  37. GRB 990806, optical observations
  38. GRB 990806, Optical Observations
  39. GRB990806 UBVRIJHK observations
  40. BeppoSAX ALERT GRB990806: Summer GRB
  41. GRB 990712 Optical Observations
  42. GRB990705: No Evidence for Neutrino Signal
  43. GRB 990712 Optical Decay: Indication of Bright Host Galaxy
  44. VLT spectrum of GRB990712
  45. GRB 990712
  46. Late-time HST/STIS Observations of GRB 990510
  47. Refined BeppoSAX-WFC position of GRB990712
  48. GRB 990705, R-band observations
  49. Updated IPN localization of GRB990705
  50. IPN localization of GRB990704
  51. IPN localization of GRB990705
  52. Infrared and Optical Observations of GRB990705
  53. GRB 990705, radio observations
  54. GRB990704 radio and optical observations
  55. GRB 990704 X-ray Observations
  56. GRB 990704 Optical Observations
  57. GRB 990704, optical observations
  58. GRB990704
  59. GRB990705: Intriguing Positional Coincidences
  60. GRB990704
  61. GRB990704, optical observations
  62. Identification of a possible optical counterpart for GRB990704
  63. GRB990704
  64. Refined BeppoSAX-WFC position of GRB990704
  65. GRB990704: BeppoSAX detection
  66. Optical Observations of GRB990627
  67. GRB 990627, radio observations
  68. GRB990627: BeppoSAX-WFC final location
  69. BeppoSAX: GRB990625
  70. Late-time HST/STIS Observation of GRB 990123
  71. GRB 990506 - clarification to GCN 352
  72. GRB 990506 - Optical Observations
  73. Optical Observations of GRB 990506
  74. GRB 990506 Radio Transient
  75. GRB990527 Optical Observations
  76. X-ray/GRB 1SAX J0835.9+5118, Optical Observation
  77. IPN error box for GRB990527
  78. Late Afterglows of GRBs 990510, 990123
  79. X-ray/GRB 1SAX J0835.9+5118, TNG V and R observations
  80. X-ray/GRB 1SAX J0835.9+5118, BATSE Observation
  81. X-ray/GRB 1SAX J0835.9+5118, Optical Observations
  82. GRB 990506 optical observation
  83. X-ray/GRB 1SAX J0835.9+5118, Optical Observation
  84. X-ray/GRB 1SAX J0835.9+5118, Optical Observation
  85. X-ray/GRB 1SAX J0835.9+5118, Optical Observation
  86. X-ray/GRB 1SAX J0835.9+5118, Optical Observation
  87. radio observations of X-ray/GRB transient field
  88. optical observation of the X-ray/GRB transient SAX J0835.9+5118
  89. Optical report on X-ray/GRB transient
  90. radio detection of X-ray/GRB transient
  91. BeppoSAX: A new fast X-ray transient
  92. GRB 990510: optical observations
  93. GRB990510: photometric and spectroscopic observations with the VLT
  94. GRB 990510: optical linear polarization
  95. GRB 990510: optical observations
  96. GRB990510, VI observations
  97. GRB 990506 R band observations
  98. GRB990510: X-ray afterglow
  99. GRB 990510: optical observation
  100. VLT spectrum of GRB990510

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