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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"

28048 results found.

  1. GRB 050906, summary of radio observations
  2. GRB051001: Swift UVOT Upper Limits
  3. GRB 050925: Second Epoch WSRT Radio Observations
  4. GRB 051001: I-band limit
  5. GRB 051001: AAT infra-red observations
  6. GRB 051001: Swift-BAT refined analysis
  7. GRB 051001: Swift Detection of a Burst
  8. GRB 050820A: NIR photometry at the TNG
  9. GRB050925: Swift/XRT limits
  10. GRB/SGR 050925: IR Observations
  11. GRB 050922C: break in the lightcurve
  12. GRB050925: Swift UVOT upper limits
  13. Refined analysis of the Swift-BAT soft short burst
  14. GRB050925: Faulkes Telescope North R-band limit
  15. GRB050925: Swift-BAT detection of a short burst
  16. GRB050922C: TNG spectroscopic observations
  17. GRB050922B: refined XRT analysis
  18. GRB050922B: Swift UVOT early upper limits.
  19. GRB050922C: Optical Observations
  20. GRB 050922C: Swift XRT refined analysis
  21. HETE Fregate observations of GRB 050922C
  22. GRB 050922C: Swift-BAT refined analysis
  23. GRB 050922B: Swift-BAT refined analysis
  24. GRB 050922C: optical obserations
  25. GRB 050922C: NOT optical observations
  26. GRB 050922C: Swift detection of a bright burst
  27. GRB 050922B: ROTSE-III Optical Limits
  28. GRB 050922B,optical observation
  29. GRB050922B: Swift-BAT detection of a weak long burst
  30. GRB050820B: analysis of the XMM-Newton observation
  31. GRB050916: Swift/UVOT Upper Limits
  32. GRB 050916: Swift-BAT refined analysis
  33. Swift-BAT trigger 155764 is not a GRB
  34. Swift-BAT trigger 155764 is probably not a GRB
  35. Swift trigger 155764: bad XRT centroid
  36. Swift-BAT trigger 155535 is definitely not a GRB
  37. GRB050916 : Swift-XRT refined analysis
  38. GRB 050915B: Swift-BAT refined analysis
  39. GRB 050915B: Swift/UVOT Upper Limits
  40. GRB 050915a: IR Transient
  41. GRB 050915b, SMARTS optical/IR observations
  42. GRB050915B: Swift-BAT detection of a long bright burst
  43. GRB050915: Swift/UVOT upper limits
  44. GRB 050915: IR Observations
  45. GRB 050915: Swift XRT refined analysis
  46. GRB 050915: Swift-BAT refined analysis
  47. GRB 050915: Swift detection of a GRB
  48. GRB050911: Upper limit on X-ray afterglow
  49. Swift-BAT trigger 155072 ground analysis
  50. Swift-BAT trigger 155072 is probably not a GRB
  51. GRB 050908: DEIMOS spectrum and further analysis
  52. GRB 050911, optical content of Swift/XRT error box
  53. GRB 050911: Swift-BAT refined analysis
  54. GRB 050911: z~0.16 cluster in the field
  55. GRB050911: Swift-BAT detection of a long burst
  56. GRB 050910a: TAROT early optical limits
  57. WIRO observations in I of GRB 050908
  58. GRB 050906: Possible X-ray Counterpart
  59. GRB050908: Swift/UVOT Early upper limits
  60. GRB050908 : Swift-XRT refined analysis
  61. GRB 050908: Swift-BAT refined analysis
  62. GRB 050908: Optical observations
  63. GRB 050908: Optical Observations
  64. GRB 050908: Swift detection of a burst
  65. GRB 050906: Optical observations at the Very Large Telescope
  66. GRB 050904 BAT refined analysis of complete data set
  67. GRB 050904: Subaru Optical Spectroscopy
  68. GRB 050906: MARGE Optical Limits
  69. GRB 050906: Swift-BAT refined analysis
  70. GRB 050906: Swift XRT upper limit
  71. GRB 050906: Radio Observations
  72. GRB 050904: Keck I-band Imaging
  73. GRB050906: P60 Observations
  74. GRB 050904: more VLT NIR observations
  75. GRB 050904: photometric redshift
  76. GRB 050904: Swift/UVOT observations
  77. GRB 050904: NIR object inside the XRT error box
  78. GRB 050904: early Swift XRT analysis results
  79. GRB 050904: SOAR YJ and PROMPT Ic Observations
  80. GRB050904: Optical Observations
  81. GRB050904: P60 Observations
  82. GRB 050904: TAROT optical limits
  83. GRB 050827 : OSN 1.5m optical observations
  84. GRB 050827: P200 NIR Observations
  85. GRB050827: Swift/UVOT upper limits
  86. GRB 050827: Optical Limit
  87. GRB 050827: XRT possible afterglow detection
  88. GRB 050826 : Lulin R band observation
  89. GRB050824: Maidanak optical limits
  90. GRB 050827: Swift-BAT refined analysis
  91. Subaru Observations of GRB050724
  92. GRB 050826: Optical Candidate
  93. GRB 050826: Swift XRT preliminary analysis results
  94. GRB 050826: BAT refined analysis
  95. GRB050826: Swift/UVOT early upper limits
  96. GRB050826: Swift-BAT detection of a long burst
  97. GRB050824: MASTER final analysis of the OT observations
  98. Swift-BAT trigger 152038 is probably not a GRB
  99. GRB 050824: XRT refined analysis and possible afterglow detection
  100. GRB 050824: BAT refined analysis of a soft weak burst

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