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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"

32796 results found.

  1. GRB 991216 Optical Observations
  2. GRB 991216, optical observations
  3. GRB 991208 SAO-RAS Spectroscopy
  4. SAX J2303.2+0015: an x-ray/GRB?
  5. GRB 991216, Optical Transient
  6. GRB 991216, Optical Afterglow
  7. GRB 991216: Comparison with DPOSS images
  8. GRB 991208 optical observations
  9. Lowell/Perkins observation of GRB 991216
  10. GRB 991216 Optical Observation
  11. GRB 991208 Keck Spectroscopy
  12. GRB 991216: Extremely bright BATSE burst
  13. GRB991208, optical observations
  14. GRB 991208 Keck Spectroscopy
  15. GRB991208 - millimeter detection
  16. GRB 991208, Optical Observation
  17. GRB 991208 - OVRO detection
  18. GRB 991208 Optical Decay
  19. GRB 991208 optical observations
  20. GRB 991208 optical observations
  21. GRB 991208: Radio Observations
  22. IPN localization of GRB991208
  23. Optical Observations of GRB991105
  24. GRB991106: BeppoSAX/BATSE results
  25. GRB 991106, optical observations
  26. GRB991106, near-infrared observations
  27. BeppoSAX NFI Observation of GRB991106
  28. GRB 991106, radio observations
  29. GRB991106: the first BeppoSAX short GRB detection?
  30. GRB 991105: BATSE Observations
  31. IPN localization of GRB991105
  32. GRB 991106 Optical Observations
  33. GRB 991105, optical observations
  34. GRB991106, optical observation at SAO-RAS
  35. GRB 991106, LOTIS Optical Observations
  36. GRB 991106, optical observations
  37. BeppoSAX GRB Alert: GRB991106
  38. BeppoSAX MAIL n. 99/30: GRB991105 refined position (fwd)
  39. GRB ALERT: GRB991105
  40. GRB 991014 - X-ray afterglow identification by BeppoSAX-NFI
  41. GRB 991014, Optical Observations
  42. GRB 991014 - BeppoSAX NFI observations
  43. GRB 991014, Optical Observations
  44. GRB 991014, radio observations
  45. GRB991014 BATSE Observations
  46. GRB 991014, Optical Observations
  47. GRB 991014, optical observations
  48. Super-LOTIS optical observation of GRB991014
  49. IPN/NFI error box for GRB991014
  50. IPN localization of GRB991014 - CORRECTION
  51. IPN localization of GRB991014
  52. BeppoSAX ALERT: GRB991014
  53. GRB 990915 optical observations
  54. GRB 990907 optical observations
  55. BATSE GRB trigger criteria
  56. Optical Observations of GRB990907
  57. IPN error box for GRB990915 (=BATSE 7766)
  58. IPN localization of BATSE #7766 (GRB990915)
  59. IPN localization of GRB990907
  60. GRB990908, another BeppoSAX-GRBM/WFC burst detection
  61. BeppoSAX MAIL n. 99/24: GRB ALERT: GRB990907
  62. GRB 990712 Late Optical Decay and Host Galaxy
  63. GRB 990712, Optical Observation
  64. GRB990806: BATSE Observations
  65. GRB 990806 Optical observations
  66. Optical Observations of GRB990806
  67. GRB 990806, Optical Observations
  68. GRB 990806, optical observations
  69. GRB 990806, Optical Observations
  70. GRB990806 UBVRIJHK observations
  71. BeppoSAX ALERT GRB990806: Summer GRB
  72. GRB 990712 Optical Observations
  73. GRB990705: No Evidence for Neutrino Signal
  74. GRB 990712 Optical Decay: Indication of Bright Host Galaxy
  75. VLT spectrum of GRB990712
  76. GRB 990712
  77. Late-time HST/STIS Observations of GRB 990510
  78. Refined BeppoSAX-WFC position of GRB990712
  79. GRB 990705, R-band observations
  80. Updated IPN localization of GRB990705
  81. IPN localization of GRB990704
  82. IPN localization of GRB990705
  83. Infrared and Optical Observations of GRB990705
  84. GRB 990705, radio observations
  85. GRB990704 radio and optical observations
  86. GRB 990704 X-ray Observations
  87. GRB 990704 Optical Observations
  88. GRB 990704, optical observations
  89. GRB990704
  90. GRB990705: Intriguing Positional Coincidences
  91. GRB990704
  92. GRB990704, optical observations
  93. Identification of a possible optical counterpart for GRB990704
  94. GRB990704
  95. Refined BeppoSAX-WFC position of GRB990704
  96. GRB990704: BeppoSAX detection
  97. Optical Observations of GRB990627
  98. GRB 990627, radio observations
  99. GRB990627: BeppoSAX-WFC final location
  100. BeppoSAX: GRB990625

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