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

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