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

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