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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"

37509 results found.

  1. GRB 991216, optical observations
  2. GRB 991216 Optical Observations
  3. GRB 991216 Optical spectroscopy/imaging
  4. K observations of GRB991216
  5. GRB 991217 (SAX J2303.2+0015) Optical observations
  6. GRB991216 Spectroscopy
  7. Lowell/Perkins observation of GRB 991216
  8. GRB991216, optical observations
  9. Refined IPN localization of GRB991216
  10. GRB 991216 Radio Observations
  11. GRB 991217
  12. GRB 991208 Keck Spectroscopy
  13. GRB 991208 Infrared Detection
  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. GRB 991216: Comparison with DPOSS images
  22. GRB 991208 optical observations
  23. Lowell/Perkins observation of GRB 991216
  24. GRB 991216 Optical Observation
  25. GRB 991208 Keck Spectroscopy
  26. GRB 991216: Extremely bright BATSE burst
  27. GRB991208, optical observations
  28. GRB 991208 Keck Spectroscopy
  29. GRB991208 - millimeter detection
  30. GRB 991208, Optical Observation
  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 GRB Alert: GRB991106
  52. BeppoSAX MAIL n. 99/30: GRB991105 refined position (fwd)
  53. GRB ALERT: GRB991105
  54. GRB 991014 - X-ray afterglow identification by BeppoSAX-NFI
  55. GRB 991014, Optical Observations
  56. GRB 991014 - BeppoSAX NFI observations
  57. GRB 991014, Optical Observations
  58. GRB 991014, radio observations
  59. GRB991014 BATSE Observations
  60. GRB 991014, Optical Observations
  61. GRB 991014, optical observations
  62. Super-LOTIS optical observation of GRB991014
  63. IPN/NFI error box for GRB991014
  64. IPN localization of GRB991014 - CORRECTION
  65. IPN localization of GRB991014
  66. BeppoSAX ALERT: GRB991014
  67. GRB 990915 optical observations
  68. GRB 990907 optical observations
  69. BATSE GRB trigger criteria
  70. Optical Observations of GRB990907
  71. IPN error box for GRB990915 (=BATSE 7766)
  72. IPN localization of BATSE #7766 (GRB990915)
  73. IPN localization of GRB990907
  74. GRB990908, another BeppoSAX-GRBM/WFC burst detection
  75. BeppoSAX MAIL n. 99/24: GRB ALERT: GRB990907
  76. GRB 990712 Late Optical Decay and Host Galaxy
  77. GRB 990712, Optical Observation
  78. GRB990806: BATSE Observations
  79. GRB 990806 Optical observations
  80. Optical Observations of GRB990806
  81. GRB 990806, Optical Observations
  82. GRB 990806, optical observations
  83. GRB 990806, Optical Observations
  84. GRB990806 UBVRIJHK observations
  85. BeppoSAX ALERT GRB990806: Summer GRB
  86. GRB 990712 Optical Observations
  87. GRB990705: No Evidence for Neutrino Signal
  88. GRB 990712 Optical Decay: Indication of Bright Host Galaxy
  89. VLT spectrum of GRB990712
  90. GRB 990712
  91. Late-time HST/STIS Observations of GRB 990510
  92. Refined BeppoSAX-WFC position of GRB990712
  93. GRB 990705, R-band observations
  94. Updated IPN localization of GRB990705
  95. IPN localization of GRB990704
  96. IPN localization of GRB990705
  97. Infrared and Optical Observations of GRB990705
  98. GRB 990705, radio observations
  99. GRB990704 radio and optical observations
  100. GRB 990704 X-ray Observations

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