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

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