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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"

40633 results found.

  1. GRB 991208 Keck Spectroscopy
  2. GRB 991208 Infrared Detection
  3. GRB991216
  4. GRB 991216--Summary of RXTE Observations
  5. GRB 991216 Optical Observations
  6. GRB 991216, optical observations
  7. GRB 991208 SAO-RAS Spectroscopy
  8. SAX J2303.2+0015: an x-ray/GRB?
  9. GRB 991216, Optical Transient
  10. GRB 991216, Optical Afterglow
  11. GRB991216 ('Beethoven Burst') B, R, and K Observations
  12. GRB 991216: Comparison with DPOSS images
  13. GRB991216, infrared observations
  14. GRB991216 Optical Observations
  15. GRB 991208 optical observations
  16. Lowell/Perkins observation of GRB 991216
  17. GRB 991216 Optical Observation
  18. GRB 991208 Keck Spectroscopy
  19. GRB 991216: Extremely bright BATSE burst
  20. R-band Observations of GRB991208 at TNG
  21. GRB991208, optical observations
  22. GRB 991208 Keck Spectroscopy
  23. GRB991208 - millimeter detection
  24. GRB991208 15-GHz observations
  25. GRB991208, optical observations
  26. GRB 991208 - OVRO detection
  27. GRB 991208 Optical Decay
  28. GRB 991208 optical observations
  29. GRB 991208 optical observations
  30. GRB 991208: Radio Observations
  31. Optical Observations of GRB991105
  32. GRB991106: BeppoSAX/BATSE results
  33. GRB 991106, optical observations
  34. GRB991106, near-infrared observations
  35. BeppoSAX NFI Observation of GRB991106
  36. GRB 991106, radio observations
  37. GRB991106: the first BeppoSAX short GRB detection?
  38. GRB 991105: BATSE Observations
  39. GRB 991106 Optical Observations
  40. GRB 991105, optical observations
  41. GRB991106, optical observation at SAO-RAS
  42. GRB 991106, LOTIS Optical Observations
  43. GRB 991106, optical observations
  44. BeppoSAX refined position for GRB991106
  45. BeppoSAX GRB Alert: GRB991106
  46. Revised BeppoSAX WFC position of GRB991105
  47. GRB991105: SAX-GRBM/-WFC detection
  48. BeppoSAX MAIL n. 99/30: GRB991105 refined position (fwd)
  49. GRB ALERT: GRB991105
  50. GRB 991014 - X-ray afterglow identification by BeppoSAX-NFI
  51. GRB 991014, Optical Observations
  52. GRB 991014 - BeppoSAX NFI observations
  53. GRB 991014, Optical Observations
  54. GRB 991014, radio observations
  55. GRB991014 BATSE Observations
  56. GRB 991014, Optical Observations
  57. GRB 991014, optical observations
  58. Super-LOTIS optical observation of GRB991014
  59. BeppoSAX ALERT: GRB991014
  60. GRB 990915 optical observations
  61. GRB 990907 optical observations
  62. Optical Observations of GRB990907
  63. GRB990907: BeppoSAX follow up and X-ray afterglow
  64. GRB990907 and 990908
  65. GRB990907: refined WFC position
  66. GRB 990712 Late Optical Decay and Host Galaxy
  67. GRB 990712, Optical Observation
  68. GRB990806 BeppoSAX follow up
  69. GRB990806: BATSE Observations
  70. GRB 990806 Optical observations
  71. Optical Observations of GRB990806
  72. GRB 990806, Optical Observations
  73. GRB 990806, optical observations
  74. GRB 990806, Optical Observations
  75. GRB990806 UBVRIJHK observations
  76. BeppoSAX ALERT GRB990806: Summer GRB
  77. GRB 990712 Optical Observations
  78. GRB990705: No Evidence for Neutrino Signal
  79. GRB 990712 Optical Decay: Indication of Bright Host Galaxy
  80. VLT spectrum of GRB990712
  81. GRB 990712
  82. Late-time HST/STIS Observations of GRB 990510
  83. Refined BeppoSAX-WFC position of GRB990712
  84. GRB 990705, R-band observations
  85. Updated IPN localization of GRB990705
  86. Infrared and Optical Observations of GRB990705
  87. GRB 990705, radio observations
  88. GRB990704 radio and optical observations
  89. GRB 990704 X-ray Observations
  90. GRB 990704 Optical Observations
  91. GRB 990704, optical observations
  92. GRB990705: Intriguing Positional Coincidences
  93. GRB990704
  94. GRB990704, optical observations
  95. Identification of a possible optical counterpart for GRB990704
  96. GRB990704
  97. Refined BeppoSAX-WFC position of GRB990704
  98. GRB990704: BeppoSAX detection
  99. BeppoSAX NFI Observation of GRB990627 X-ray afterglow
  100. Optical Observations of GRB990627

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