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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"

26352 results found.

  1. Swift-BAT trigger 158700 is a probable Cosmic Ray Shower Event
  2. GRB 051006: optical observations at Sierra Nevada
  3. GRB051006: Refined analysis of the Swift-BAT burst
  4. GRB051006: Swift detection of a burst
  5. GRB 050906, summary of radio observations
  6. GRB051001: Swift UVOT Upper Limits
  7. GRB 050925: Second Epoch WSRT Radio Observations
  8. GRB 051001: I-band limit
  9. GRB 051001: AAT infra-red observations
  10. GRB 051001: Swift-BAT refined analysis
  11. GRB 051001: Swift Detection of a Burst
  12. GRB 050820A: NIR photometry at the TNG
  13. GRB050925: Swift/XRT limits
  14. GRB/SGR 050925: IR Observations
  15. GRB 050922C: break in the lightcurve
  16. GRB050925: Swift UVOT upper limits
  17. Refined analysis of the Swift-BAT soft short burst
  18. GRB050925: Faulkes Telescope North R-band limit
  19. GRB050925: Swift-BAT detection of a short burst
  20. GRB050922C: TNG spectroscopic observations
  21. GRB050922B: refined XRT analysis
  22. GRB050922B: Swift UVOT early upper limits.
  23. GRB050922C: Optical Observations
  24. GRB 050922C: Swift XRT refined analysis
  25. HETE Fregate observations of GRB 050922C
  26. GRB 050922C: Swift-BAT refined analysis
  27. GRB 050922B: Swift-BAT refined analysis
  28. GRB 050922C: optical obserations
  29. GRB 050922C: NOT optical observations
  30. GRB 050922C: Swift detection of a bright burst
  31. GRB 050922B: ROTSE-III Optical Limits
  32. GRB 050922B,optical observation
  33. GRB050922B: Swift-BAT detection of a weak long burst
  34. GRB050820B: analysis of the XMM-Newton observation
  35. GRB050916: Swift/UVOT Upper Limits
  36. GRB 050916: Swift-BAT refined analysis
  37. Swift-BAT trigger 155764 is not a GRB
  38. Swift-BAT trigger 155764 is probably not a GRB
  39. Swift trigger 155764: bad XRT centroid
  40. Swift-BAT trigger 155535 is definitely not a GRB
  41. GRB050916 : Swift-XRT refined analysis
  42. GRB 050915B: Swift-BAT refined analysis
  43. GRB 050915B: Swift/UVOT Upper Limits
  44. GRB 050915a: IR Transient
  45. GRB 050915b, SMARTS optical/IR observations
  46. GRB050915B: Swift-BAT detection of a long bright burst
  47. GRB050915: Swift/UVOT upper limits
  48. GRB 050915: IR Observations
  49. GRB 050915: Swift XRT refined analysis
  50. GRB 050915: Swift-BAT refined analysis
  51. GRB 050915: Swift detection of a GRB
  52. GRB050911: Upper limit on X-ray afterglow
  53. Swift-BAT trigger 155072 ground analysis
  54. Swift-BAT trigger 155072 is probably not a GRB
  55. GRB 050908: DEIMOS spectrum and further analysis
  56. GRB 050911, optical content of Swift/XRT error box
  57. GRB 050911: Swift-BAT refined analysis
  58. GRB 050911: z~0.16 cluster in the field
  59. GRB050911: Swift-BAT detection of a long burst
  60. GRB 050910a: TAROT early optical limits
  61. WIRO observations in I of GRB 050908
  62. GRB 050906: Possible X-ray Counterpart
  63. GRB050908: Swift/UVOT Early upper limits
  64. GRB050908 : Swift-XRT refined analysis
  65. GRB 050908: Swift-BAT refined analysis
  66. GRB 050908: Optical observations
  67. GRB 050908: Optical Observations
  68. GRB 050908: Swift detection of a burst
  69. GRB 050906: Optical observations at the Very Large Telescope
  70. GRB 050904 BAT refined analysis of complete data set
  71. GRB 050904: Subaru Optical Spectroscopy
  72. GRB 050906: MARGE Optical Limits
  73. GRB 050906: Swift-BAT refined analysis
  74. GRB 050906: Swift XRT upper limit
  75. GRB 050906: Radio Observations
  76. GRB 050904: Keck I-band Imaging
  77. GRB050906: P60 Observations
  78. GRB 050904: more VLT NIR observations
  79. GRB 050904: photometric redshift
  80. GRB 050904: Swift/UVOT observations
  81. GRB 050904: NIR object inside the XRT error box
  82. GRB 050904: early Swift XRT analysis results
  83. GRB 050904: SOAR YJ and PROMPT Ic Observations
  84. GRB050904: Optical Observations
  85. GRB050904: P60 Observations
  86. GRB 050904: TAROT optical limits
  87. GRB 050827 : OSN 1.5m optical observations
  88. GRB 050827: P200 NIR Observations
  89. GRB050827: Swift/UVOT upper limits
  90. GRB 050827: Optical Limit
  91. GRB 050827: XRT possible afterglow detection
  92. GRB 050826 : Lulin R band observation
  93. GRB050824: Maidanak optical limits
  94. GRB 050827: Swift-BAT refined analysis
  95. Subaru Observations of GRB050724
  96. GRB 050826: Optical Candidate
  97. GRB 050826: Swift XRT preliminary analysis results
  98. GRB 050826: BAT refined analysis
  99. GRB050826: Swift/UVOT early upper limits
  100. GRB050826: Swift-BAT detection of a long burst

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