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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"

37011 results found.

  1. GRB 991216, optical observations
  2. GRB 991208 SAO-RAS Spectroscopy
  3. SAX J2303.2+0015: an x-ray/GRB?
  4. GRB 991216, Optical Transient
  5. GRB 991216, Optical Afterglow
  6. GRB 991216: Comparison with DPOSS images
  7. GRB991216 Optical Observations
  8. GRB 991208 optical observations
  9. Lowell/Perkins observation of GRB 991216
  10. GRB 991216 Optical Observation
  11. GRB 991208 Keck Spectroscopy
  12. GRB 991216: Extremely bright BATSE burst
  13. GRB991208, optical observations
  14. GRB 991208 Keck Spectroscopy
  15. GRB991208 - millimeter detection
  16. GRB 991208, Optical Observation
  17. GRB991208 15-GHz observations
  18. GRB 991208 - OVRO detection
  19. GRB 991208 Optical Decay
  20. GRB 991208 optical observations
  21. GRB 991208 optical observations
  22. GRB 991208: Radio Observations
  23. IPN localization of GRB991208
  24. Optical Observations of GRB991105
  25. GRB991106: BeppoSAX/BATSE results
  26. GRB 991106, optical observations
  27. GRB991106, near-infrared observations
  28. BeppoSAX NFI Observation of GRB991106
  29. GRB 991106, radio observations
  30. GRB991106: the first BeppoSAX short GRB detection?
  31. GRB 991105: BATSE Observations
  32. IPN localization of GRB991105
  33. GRB 991106 Optical Observations
  34. GRB 991105, optical observations
  35. GRB991106, optical observation at SAO-RAS
  36. GRB 991106, LOTIS Optical Observations
  37. GRB 991106, optical observations
  38. BeppoSAX GRB Alert: GRB991106
  39. BeppoSAX MAIL n. 99/30: GRB991105 refined position (fwd)
  40. GRB ALERT: GRB991105
  41. GRB 991014 - X-ray afterglow identification by BeppoSAX-NFI
  42. GRB 991014, Optical Observations
  43. GRB 991014 - BeppoSAX NFI observations
  44. GRB 991014, Optical Observations
  45. GRB 991014, radio observations
  46. GRB991014 BATSE Observations
  47. GRB 991014, Optical Observations
  48. GRB 991014, optical observations
  49. Super-LOTIS optical observation of GRB991014
  50. IPN/NFI error box for GRB991014
  51. IPN localization of GRB991014 - CORRECTION
  52. IPN localization of GRB991014
  53. BeppoSAX ALERT: GRB991014
  54. GRB 990915 optical observations
  55. GRB 990907 optical observations
  56. BATSE GRB trigger criteria
  57. Optical Observations of GRB990907
  58. IPN error box for GRB990915 (=BATSE 7766)
  59. IPN localization of BATSE #7766 (GRB990915)
  60. IPN localization of GRB990907
  61. GRB990908, another BeppoSAX-GRBM/WFC burst detection
  62. BeppoSAX MAIL n. 99/24: GRB ALERT: GRB990907
  63. GRB 990712 Late Optical Decay and Host Galaxy
  64. GRB 990712, Optical Observation
  65. GRB990806: BATSE Observations
  66. GRB 990806 Optical observations
  67. Optical Observations of GRB990806
  68. GRB 990806, Optical Observations
  69. GRB 990806, optical observations
  70. GRB 990806, Optical Observations
  71. GRB990806 UBVRIJHK observations
  72. GRB990806: possible X-ray afterglow, BeppoSAX
  73. BeppoSAX ALERT GRB990806: Summer GRB
  74. GRB 990712 Optical Observations
  75. GRB990705: No Evidence for Neutrino Signal
  76. GRB 990712 Optical Decay: Indication of Bright Host Galaxy
  77. VLT spectrum of GRB990712
  78. GRB 990712
  79. Late-time HST/STIS Observations of GRB 990510
  80. Refined BeppoSAX-WFC position of GRB990712
  81. GRB 990705, R-band observations
  82. Updated IPN localization of GRB990705
  83. IPN localization of GRB990704
  84. IPN localization of GRB990705
  85. Infrared and Optical Observations of GRB990705
  86. GRB 990705, radio observations
  87. GRB990704 radio and optical observations
  88. BeppoSAX GRB990705: possible X-ray afterglow
  89. GRB 990704 X-ray Observations
  90. GRB 990704 Optical Observations
  91. GRB 990704, optical observations
  92. GRB990704
  93. GRB990705: Intriguing Positional Coincidences
  94. GRB990704
  95. GRB990704, optical observations
  96. GRB990704: possible X-ray afterglow
  97. Identification of a possible optical counterpart for GRB990704
  98. GRB990704
  99. Refined BeppoSAX-WFC position of GRB990704
  100. GRB990704: BeppoSAX detection

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