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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. GRB 991217 (SAX J2303.2+0015) Optical observations
  3. GRB991216 radio observations
  4. GRB991216 Spectroscopy
  5. Lowell/Perkins observation of GRB 991216
  6. GRB991216, optical observations
  7. GRB991216 Optical and infrared observations of Beethoven Burst
  8. Refined IPN localization of GRB991216
  9. GRB 991216 Radio Observations
  10. GRB 991217
  11. GRB 991208 Keck Spectroscopy
  12. GRB 991208 Infrared Detection
  13. GRB991216
  14. GRB 991216--Summary of RXTE Observations
  15. GRB 991216 Optical Observations
  16. GRB 991216, optical observations
  17. GRB 991208 SAO-RAS Spectroscopy
  18. SAX J2303.2+0015: an x-ray/GRB?
  19. GRB 991216, Optical Transient
  20. GRB 991216, Optical Afterglow
  21. GRB991216 ('Beethoven Burst') B, R, and K Observations
  22. GRB 991216: Comparison with DPOSS images
  23. GRB991216, infrared observations
  24. GRB991216 Optical Observations
  25. GRB 991208 optical observations
  26. Lowell/Perkins observation of GRB 991216
  27. GRB 991216 Optical Observation
  28. GRB 991208 Keck Spectroscopy
  29. GRB 991216: Extremely bright BATSE burst
  30. R-band Observations of GRB991208 at TNG
  31. GRB991208, optical observations
  32. GRB 991208 Keck Spectroscopy
  33. GRB991208 - millimeter detection
  34. GRB 991208, Optical Observation
  35. GRB991208 15-GHz observations
  36. GRB991208, optical observations
  37. GRB 991208 - OVRO detection
  38. GRB 991208 Optical Decay
  39. GRB 991208 optical observations
  40. GRB 991208 optical observations
  41. GRB 991208: Radio Observations
  42. IPN localization of GRB991208
  43. Optical Observations of GRB991105
  44. GRB991106: BeppoSAX/BATSE results
  45. GRB 991106, optical observations
  46. GRB991106, near-infrared observations
  47. BeppoSAX NFI Observation of GRB991106
  48. GRB 991106, radio observations
  49. GRB991106: the first BeppoSAX short GRB detection?
  50. GRB 991105: BATSE Observations
  51. IPN localization of GRB991105
  52. GRB 991106 Optical Observations
  53. GRB 991105, optical observations
  54. GRB991106, optical observation at SAO-RAS
  55. GRB 991106, LOTIS Optical Observations
  56. GRB 991106, optical observations
  57. BeppoSAX refined position for GRB991106
  58. BeppoSAX GRB Alert: GRB991106
  59. Revised BeppoSAX WFC position of GRB991105
  60. GRB991105: SAX-GRBM/-WFC detection
  61. BeppoSAX MAIL n. 99/30: GRB991105 refined position (fwd)
  62. GRB ALERT: GRB991105
  63. GRB 991014 - X-ray afterglow identification by BeppoSAX-NFI
  64. GRB 991014, Optical Observations
  65. GRB 991014 - BeppoSAX NFI observations
  66. GRB 991014, Optical Observations
  67. GRB 991014, radio observations
  68. GRB991014 BATSE Observations
  69. GRB 991014, Optical Observations
  70. GRB 991014, optical observations
  71. Super-LOTIS optical observation of GRB991014
  72. IPN/NFI error box for GRB991014
  73. IPN localization of GRB991014 - CORRECTION
  74. IPN localization of GRB991014
  75. BeppoSAX ALERT: GRB991014
  76. GRB 990915 optical observations
  77. GRB 990907 optical observations
  78. BATSE GRB trigger criteria
  79. Optical Observations of GRB990907
  80. IPN error box for GRB990915 (=BATSE 7766)
  81. IPN localization of BATSE #7766 (GRB990915)
  82. GRB990907: BeppoSAX follow up and X-ray afterglow
  83. GRB990907 and 990908
  84. IPN localization of GRB990907
  85. GRB990908, another BeppoSAX-GRBM/WFC burst detection
  86. GRB990907: refined WFC position
  87. BeppoSAX MAIL n. 99/24: GRB ALERT: GRB990907
  88. GRB 990712 Late Optical Decay and Host Galaxy
  89. GRB 990712, Optical Observation
  90. GRB990806 BeppoSAX follow up
  91. GRB990806: BATSE Observations
  92. GRB 990806 Optical observations
  93. Optical Observations of GRB990806
  94. GRB 990806, Optical Observations
  95. GRB 990806, optical observations
  96. GRB 990806, Optical Observations
  97. GRB990806 UBVRIJHK observations
  98. GRB990806: possible X-ray afterglow, BeppoSAX
  99. BeppoSAX ALERT GRB990806: Summer GRB
  100. GRB 990712 Optical Observations

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