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

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