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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. GRB991216
  2. GRB 991216--Summary of RXTE Observations
  3. GRB 991216 Optical Observations
  4. GRB 991216, optical observations
  5. GRB 991208 SAO-RAS Spectroscopy
  6. SAX J2303.2+0015: an x-ray/GRB?
  7. GRB 991216, Optical Transient
  8. GRB 991216, Optical Afterglow
  9. GRB991216 ('Beethoven Burst') B, R, and K Observations
  10. GRB 991216: Comparison with DPOSS images
  11. GRB991216, infrared observations
  12. GRB991216 Optical Observations
  13. GRB 991208 optical observations
  14. Lowell/Perkins observation of GRB 991216
  15. GRB 991216 Optical Observation
  16. GRB 991208 Keck Spectroscopy
  17. GRB 991216: Extremely bright BATSE burst
  18. R-band Observations of GRB991208 at TNG
  19. GRB991208, optical observations
  20. GRB 991208 Keck Spectroscopy
  21. GRB991208 - millimeter detection
  22. GRB 991208, Optical Observation
  23. GRB991208 15-GHz observations
  24. GRB991208, optical observations
  25. GRB 991208 - OVRO detection
  26. GRB 991208 Optical Decay
  27. GRB 991208 optical observations
  28. GRB 991208 optical observations
  29. GRB 991208: Radio Observations
  30. IPN localization of GRB991208
  31. Optical Observations of GRB991105
  32. GRB991106: BeppoSAX/BATSE results
  33. GRB 991106, optical observations
  34. GRB991106, near-infrared observations
  35. BeppoSAX NFI Observation of GRB991106
  36. GRB 991106, radio observations
  37. GRB991106: the first BeppoSAX short GRB detection?
  38. GRB 991105: BATSE Observations
  39. IPN localization of GRB991105
  40. GRB 991106 Optical Observations
  41. GRB 991105, optical observations
  42. GRB991106, optical observation at SAO-RAS
  43. GRB 991106, LOTIS Optical Observations
  44. GRB 991106, optical observations
  45. BeppoSAX refined position for GRB991106
  46. BeppoSAX GRB Alert: GRB991106
  47. Revised BeppoSAX WFC position of GRB991105
  48. GRB991105: SAX-GRBM/-WFC detection
  49. BeppoSAX MAIL n. 99/30: GRB991105 refined position (fwd)
  50. GRB ALERT: GRB991105
  51. GRB 991014 - X-ray afterglow identification by BeppoSAX-NFI
  52. GRB 991014, Optical Observations
  53. GRB 991014 - BeppoSAX NFI observations
  54. GRB 991014, Optical Observations
  55. GRB 991014, radio observations
  56. GRB991014 BATSE Observations
  57. GRB 991014, Optical Observations
  58. GRB 991014, optical observations
  59. Super-LOTIS optical observation of GRB991014
  60. IPN/NFI error box for GRB991014
  61. IPN localization of GRB991014 - CORRECTION
  62. IPN localization of GRB991014
  63. BeppoSAX ALERT: GRB991014
  64. GRB 990915 optical observations
  65. GRB 990907 optical observations
  66. BATSE GRB trigger criteria
  67. Optical Observations of GRB990907
  68. IPN error box for GRB990915 (=BATSE 7766)
  69. IPN localization of BATSE #7766 (GRB990915)
  70. GRB990907: BeppoSAX follow up and X-ray afterglow
  71. GRB990907 and 990908
  72. IPN localization of GRB990907
  73. GRB990908, another BeppoSAX-GRBM/WFC burst detection
  74. GRB990907: refined WFC position
  75. BeppoSAX MAIL n. 99/24: GRB ALERT: GRB990907
  76. GRB 990712 Late Optical Decay and Host Galaxy
  77. GRB 990712, Optical Observation
  78. GRB990806 BeppoSAX follow up
  79. GRB990806: BATSE Observations
  80. GRB 990806 Optical observations
  81. Optical Observations of GRB990806
  82. GRB 990806, Optical Observations
  83. GRB 990806, optical observations
  84. GRB 990806, Optical Observations
  85. GRB990806 UBVRIJHK observations
  86. GRB990806: possible X-ray afterglow, BeppoSAX
  87. BeppoSAX ALERT GRB990806: Summer GRB
  88. GRB 990712 Optical Observations
  89. GRB990705: No Evidence for Neutrino Signal
  90. GRB 990712 Optical Decay: Indication of Bright Host Galaxy
  91. VLT spectrum of GRB990712
  92. GRB 990712
  93. Late-time HST/STIS Observations of GRB 990510
  94. Refined BeppoSAX-WFC position of GRB990712
  95. BeppoSAX NFI Observation of GRB990705
  96. BeppoSAX NFI Observation of GRB990705
  97. Updated Astrometry for the IR Counterpart of GRB990705
  98. GRB 990705, R-band observations
  99. Updated IPN localization of GRB990705
  100. IPN localization of GRB990704

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