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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"

26357 results found.

  1. GRB051008: Radio Observation
  2. GRB 051008, optical observations
  3. GRB 051008: early Swift XRT analysis
  4. GRB 051008: Swift UVOT Candidate
  5. GRB 051006: P60 Observations
  6. Swift-BAT trigger 158700 is a probable Cosmic Ray Shower Event
  7. GRB 051006: optical observations at Sierra Nevada
  8. GRB051006: Refined analysis of the Swift-BAT burst
  9. GRB051006: Swift detection of a burst
  10. GRB 050906, summary of radio observations
  11. GRB051001: Swift UVOT Upper Limits
  12. GRB 050925: Second Epoch WSRT Radio Observations
  13. GRB 051001: I-band limit
  14. GRB 051001: AAT infra-red observations
  15. GRB 051001: Swift-BAT refined analysis
  16. GRB 051001: Swift Detection of a Burst
  17. GRB 050820A: NIR photometry at the TNG
  18. GRB050925: Swift/XRT limits
  19. GRB/SGR 050925: IR Observations
  20. GRB 050922C: break in the lightcurve
  21. GRB050925: Swift UVOT upper limits
  22. Refined analysis of the Swift-BAT soft short burst
  23. GRB050925: Faulkes Telescope North R-band limit
  24. GRB050925: Swift-BAT detection of a short burst
  25. GRB050922C: TNG spectroscopic observations
  26. GRB050922B: refined XRT analysis
  27. GRB050922B: Swift UVOT early upper limits.
  28. GRB050922C: Optical Observations
  29. GRB 050922C: Swift XRT refined analysis
  30. HETE Fregate observations of GRB 050922C
  31. GRB 050922C: Swift-BAT refined analysis
  32. GRB 050922B: Swift-BAT refined analysis
  33. GRB 050922C: optical obserations
  34. GRB 050922C: NOT optical observations
  35. GRB 050922C: Swift detection of a bright burst
  36. GRB 050922B: ROTSE-III Optical Limits
  37. GRB 050922B,optical observation
  38. GRB050922B: Swift-BAT detection of a weak long burst
  39. GRB050820B: analysis of the XMM-Newton observation
  40. GRB050916: Swift/UVOT Upper Limits
  41. GRB 050916: Swift-BAT refined analysis
  42. Swift-BAT trigger 155764 is not a GRB
  43. Swift-BAT trigger 155764 is probably not a GRB
  44. Swift trigger 155764: bad XRT centroid
  45. Swift-BAT trigger 155535 is definitely not a GRB
  46. GRB050916 : Swift-XRT refined analysis
  47. GRB 050915B: Swift-BAT refined analysis
  48. GRB 050915B: Swift/UVOT Upper Limits
  49. GRB 050915a: IR Transient
  50. GRB 050915b, SMARTS optical/IR observations
  51. GRB050915B: Swift-BAT detection of a long bright burst
  52. GRB050915: Swift/UVOT upper limits
  53. GRB 050915: IR Observations
  54. GRB 050915: Swift XRT refined analysis
  55. GRB 050915: Swift-BAT refined analysis
  56. GRB 050915: Swift detection of a GRB
  57. GRB050911: Upper limit on X-ray afterglow
  58. Swift-BAT trigger 155072 ground analysis
  59. Swift-BAT trigger 155072 is probably not a GRB
  60. GRB 050908: DEIMOS spectrum and further analysis
  61. GRB 050911, optical content of Swift/XRT error box
  62. GRB 050911: Swift-BAT refined analysis
  63. GRB 050911: z~0.16 cluster in the field
  64. GRB050911: Swift-BAT detection of a long burst
  65. GRB 050910a: TAROT early optical limits
  66. WIRO observations in I of GRB 050908
  67. GRB 050906: Possible X-ray Counterpart
  68. GRB050908: Swift/UVOT Early upper limits
  69. GRB050908 : Swift-XRT refined analysis
  70. GRB 050908: Swift-BAT refined analysis
  71. GRB 050908: Optical observations
  72. GRB 050908: Optical Observations
  73. GRB 050908: Swift detection of a burst
  74. GRB 050906: Optical observations at the Very Large Telescope
  75. GRB 050904 BAT refined analysis of complete data set
  76. GRB 050904: Subaru Optical Spectroscopy
  77. GRB 050906: MARGE Optical Limits
  78. GRB 050906: Swift-BAT refined analysis
  79. GRB 050906: Swift XRT upper limit
  80. GRB 050906: Radio Observations
  81. GRB 050904: Keck I-band Imaging
  82. GRB050906: P60 Observations
  83. GRB 050904: more VLT NIR observations
  84. GRB 050904: photometric redshift
  85. GRB 050904: Swift/UVOT observations
  86. GRB 050904: NIR object inside the XRT error box
  87. GRB 050904: early Swift XRT analysis results
  88. GRB 050904: SOAR YJ and PROMPT Ic Observations
  89. GRB050904: Optical Observations
  90. GRB050904: P60 Observations
  91. GRB 050904: TAROT optical limits
  92. GRB 050827 : OSN 1.5m optical observations
  93. GRB 050827: P200 NIR Observations
  94. GRB050827: Swift/UVOT upper limits
  95. GRB 050827: Optical Limit
  96. GRB 050827: XRT possible afterglow detection
  97. GRB 050826 : Lulin R band observation
  98. GRB050824: Maidanak optical limits
  99. GRB 050827: Swift-BAT refined analysis
  100. Subaru Observations of GRB050724

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