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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. GRB 991216 Radio Observations
  2. GRB 991217
  3. GRB 991208 Keck Spectroscopy
  4. GRB 991208 Infrared Detection
  5. GRB991216
  6. GRB 991216--Summary of RXTE Observations
  7. GRB 991216 Optical Observations
  8. GRB 991216, optical observations
  9. GRB 991208 SAO-RAS Spectroscopy
  10. SAX J2303.2+0015: an x-ray/GRB?
  11. GRB 991216, Optical Transient
  12. GRB 991216, Optical Afterglow
  13. GRB991216 ('Beethoven Burst') B, R, and K Observations
  14. GRB 991216: Comparison with DPOSS images
  15. GRB991216, infrared observations
  16. GRB991216 Optical Observations
  17. GRB 991208 optical observations
  18. Lowell/Perkins observation of GRB 991216
  19. GRB 991216 Optical Observation
  20. GRB 991208 Keck Spectroscopy
  21. GRB 991216: Extremely bright BATSE burst
  22. R-band Observations of GRB991208 at TNG
  23. GRB991208, optical observations
  24. GRB 991208 Keck Spectroscopy
  25. GRB991208 - millimeter detection
  26. GRB 991208, Optical Observation
  27. GRB991208 15-GHz observations
  28. GRB991208, optical observations
  29. GRB 991208 - OVRO detection
  30. GRB 991208 Optical Decay
  31. GRB 991208 optical observations
  32. GRB 991208 optical observations
  33. GRB 991208: Radio Observations
  34. IPN localization of GRB991208
  35. Optical Observations of GRB991105
  36. GRB991106: BeppoSAX/BATSE results
  37. GRB 991106, optical observations
  38. GRB991106, near-infrared observations
  39. BeppoSAX NFI Observation of GRB991106
  40. GRB 991106, radio observations
  41. GRB991106: the first BeppoSAX short GRB detection?
  42. GRB 991105: BATSE Observations
  43. IPN localization of GRB991105
  44. GRB 991106 Optical Observations
  45. GRB 991105, optical observations
  46. GRB991106, optical observation at SAO-RAS
  47. GRB 991106, LOTIS Optical Observations
  48. GRB 991106, optical observations
  49. BeppoSAX refined position for GRB991106
  50. BeppoSAX GRB Alert: GRB991106
  51. Revised BeppoSAX WFC position of GRB991105
  52. GRB991105: SAX-GRBM/-WFC detection
  53. BeppoSAX MAIL n. 99/30: GRB991105 refined position (fwd)
  54. GRB ALERT: GRB991105
  55. GRB 991014 - X-ray afterglow identification by BeppoSAX-NFI
  56. GRB 991014, Optical Observations
  57. GRB 991014 - BeppoSAX NFI observations
  58. GRB 991014, Optical Observations
  59. GRB 991014, radio observations
  60. GRB991014 BATSE Observations
  61. GRB 991014, Optical Observations
  62. GRB 991014, optical observations
  63. Super-LOTIS optical observation of GRB991014
  64. IPN/NFI error box for GRB991014
  65. IPN localization of GRB991014 - CORRECTION
  66. IPN localization of GRB991014
  67. BeppoSAX ALERT: GRB991014
  68. GRB 990915 optical observations
  69. GRB 990907 optical observations
  70. BATSE GRB trigger criteria
  71. Optical Observations of GRB990907
  72. IPN error box for GRB990915 (=BATSE 7766)
  73. IPN localization of BATSE #7766 (GRB990915)
  74. GRB990907: BeppoSAX follow up and X-ray afterglow
  75. GRB990907 and 990908
  76. IPN localization of GRB990907
  77. GRB990908, another BeppoSAX-GRBM/WFC burst detection
  78. GRB990907: refined WFC position
  79. BeppoSAX MAIL n. 99/24: GRB ALERT: GRB990907
  80. GRB 990712 Late Optical Decay and Host Galaxy
  81. GRB 990712, Optical Observation
  82. GRB990806 BeppoSAX follow up
  83. GRB990806: BATSE Observations
  84. GRB 990806 Optical observations
  85. Optical Observations of GRB990806
  86. GRB 990806, Optical Observations
  87. GRB 990806, optical observations
  88. GRB 990806, Optical Observations
  89. GRB990806 UBVRIJHK observations
  90. GRB990806: possible X-ray afterglow, BeppoSAX
  91. BeppoSAX ALERT GRB990806: Summer GRB
  92. GRB 990712 Optical Observations
  93. GRB990705: No Evidence for Neutrino Signal
  94. GRB 990712 Optical Decay: Indication of Bright Host Galaxy
  95. VLT spectrum of GRB990712
  96. GRB 990712
  97. Late-time HST/STIS Observations of GRB 990510
  98. Refined BeppoSAX-WFC position of GRB990712
  99. BeppoSAX NFI Observation of GRB990705
  100. BeppoSAX NFI Observation of GRB990705

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