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

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