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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"

41614 results found.

  1. R-band Observations of GRB991208 at TNG
  2. GRB991208, optical observations
  3. GRB 991208 Keck Spectroscopy
  4. GRB991208 - millimeter detection
  5. GRB991208 15-GHz observations
  6. GRB991208, optical observations
  7. GRB 991208 - OVRO detection
  8. GRB 991208 Optical Decay
  9. GRB 991208 optical observations
  10. GRB 991208 optical observations
  11. GRB 991208: Radio Observations
  12. Optical Observations of GRB991105
  13. GRB991106: BeppoSAX/BATSE results
  14. GRB 991106, optical observations
  15. GRB991106, near-infrared observations
  16. BeppoSAX NFI Observation of GRB991106
  17. GRB 991106, radio observations
  18. GRB991106: the first BeppoSAX short GRB detection?
  19. GRB 991105: BATSE Observations
  20. GRB 991106 Optical Observations
  21. GRB 991105, optical observations
  22. GRB991106, optical observation at SAO-RAS
  23. GRB 991106, LOTIS Optical Observations
  24. GRB 991106, optical observations
  25. BeppoSAX refined position for GRB991106
  26. BeppoSAX GRB Alert: GRB991106
  27. Revised BeppoSAX WFC position of GRB991105
  28. GRB991105: SAX-GRBM/-WFC detection
  29. BeppoSAX MAIL n. 99/30: GRB991105 refined position (fwd)
  30. GRB ALERT: GRB991105
  31. GRB 991014 - X-ray afterglow identification by BeppoSAX-NFI
  32. GRB 991014, Optical Observations
  33. GRB 991014 - BeppoSAX NFI observations
  34. GRB 991014, Optical Observations
  35. GRB 991014, radio observations
  36. GRB991014 BATSE Observations
  37. GRB 991014, Optical Observations
  38. GRB 991014, optical observations
  39. Super-LOTIS optical observation of GRB991014
  40. BeppoSAX ALERT: GRB991014
  41. GRB 990915 optical observations
  42. GRB 990907 optical observations
  43. Optical Observations of GRB990907
  44. GRB990907: BeppoSAX follow up and X-ray afterglow
  45. GRB990907 and 990908
  46. GRB990907: refined WFC position
  47. GRB 990712 Late Optical Decay and Host Galaxy
  48. GRB 990712, Optical Observation
  49. GRB990806 BeppoSAX follow up
  50. GRB990806: BATSE Observations
  51. GRB 990806 Optical observations
  52. Optical Observations of GRB990806
  53. GRB 990806, Optical Observations
  54. GRB 990806, optical observations
  55. GRB 990806, Optical Observations
  56. GRB990806 UBVRIJHK observations
  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. GRB 990705, R-band observations
  66. Updated IPN localization of GRB990705
  67. Infrared and Optical Observations of GRB990705
  68. GRB 990705, radio observations
  69. GRB990704 radio and optical observations
  70. GRB 990704 X-ray Observations
  71. GRB 990704 Optical Observations
  72. GRB 990704, optical observations
  73. GRB990705: Intriguing Positional Coincidences
  74. GRB990704
  75. GRB990704, optical observations
  76. Identification of a possible optical counterpart for GRB990704
  77. GRB990704
  78. Refined BeppoSAX-WFC position of GRB990704
  79. GRB990704: BeppoSAX detection
  80. BeppoSAX NFI Observation of GRB990627 X-ray afterglow
  81. Optical Observations of GRB990627
  82. GRB 990627, radio observations
  83. BeppoSAX: GRB990625
  84. Late-time HST/STIS Observation of GRB 990123
  85. GRB 990506 - clarification to GCN 352
  86. GRB 990506 - Optical Observations
  87. Optical Observations of GRB 990506
  88. GRB990527 Optical Observations
  89. X-ray/GRB 1SAX J0835.9+5118, Optical Observation
  90. IPN error box for GRB990527
  91. Late Afterglows of GRBs 990510, 990123
  92. X-ray/GRB 1SAX J0835.9+5118, TNG V and R observations
  93. X-ray/GRB 1SAX J0835.9+5118, BATSE Observation
  94. X-ray/GRB 1SAX J0835.9+5118, Optical Observations
  95. X-ray/GRB 1SAX J0835.9+5118, Optical Observation
  96. X-ray/GRB 1SAX J0835.9+5118, Optical Observation
  97. X-ray/GRB 1SAX J0835.9+5118, Optical Observation
  98. X-ray/GRB 1SAX J0835.9+5118, Optical Observation
  99. radio observations of X-ray/GRB transient field
  100. optical observation of the X-ray/GRB transient SAX J0835.9+5118

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