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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"

28042 results found.

  1. GRB 051001: Swift Detection of a Burst
  2. GRB 050820A: NIR photometry at the TNG
  3. GRB050925: Swift/XRT limits
  4. GRB/SGR 050925: IR Observations
  5. GRB 050922C: break in the lightcurve
  6. GRB050925: Swift UVOT upper limits
  7. Refined analysis of the Swift-BAT soft short burst
  8. GRB050925: Faulkes Telescope North R-band limit
  9. GRB050925: Swift-BAT detection of a short burst
  10. GRB050922C: TNG spectroscopic observations
  11. GRB050922B: refined XRT analysis
  12. GRB050922B: Swift UVOT early upper limits.
  13. GRB050922C: Optical Observations
  14. GRB 050922C: Swift XRT refined analysis
  15. HETE Fregate observations of GRB 050922C
  16. GRB 050922C: Swift-BAT refined analysis
  17. GRB 050922B: Swift-BAT refined analysis
  18. GRB 050922C: optical obserations
  19. GRB 050922C: NOT optical observations
  20. GRB 050922C: Swift detection of a bright burst
  21. GRB 050922B: ROTSE-III Optical Limits
  22. GRB 050922B,optical observation
  23. GRB050922B: Swift-BAT detection of a weak long burst
  24. GRB050820B: analysis of the XMM-Newton observation
  25. GRB050916: Swift/UVOT Upper Limits
  26. GRB 050916: Swift-BAT refined analysis
  27. Swift-BAT trigger 155764 is not a GRB
  28. Swift-BAT trigger 155764 is probably not a GRB
  29. Swift trigger 155764: bad XRT centroid
  30. Swift-BAT trigger 155535 is definitely not a GRB
  31. GRB050916 : Swift-XRT refined analysis
  32. GRB 050915B: Swift-BAT refined analysis
  33. GRB 050915B: Swift/UVOT Upper Limits
  34. GRB 050915a: IR Transient
  35. GRB 050915b, SMARTS optical/IR observations
  36. GRB050915B: Swift-BAT detection of a long bright burst
  37. GRB050915: Swift/UVOT upper limits
  38. GRB 050915: IR Observations
  39. GRB 050915: Swift XRT refined analysis
  40. GRB 050915: Swift-BAT refined analysis
  41. GRB 050915: Swift detection of a GRB
  42. GRB050911: Upper limit on X-ray afterglow
  43. Swift-BAT trigger 155072 ground analysis
  44. Swift-BAT trigger 155072 is probably not a GRB
  45. GRB 050908: DEIMOS spectrum and further analysis
  46. GRB 050911, optical content of Swift/XRT error box
  47. GRB 050911: Swift-BAT refined analysis
  48. GRB 050911: z~0.16 cluster in the field
  49. GRB050911: Swift-BAT detection of a long burst
  50. GRB 050910a: TAROT early optical limits
  51. WIRO observations in I of GRB 050908
  52. GRB 050906: Possible X-ray Counterpart
  53. GRB050908: Swift/UVOT Early upper limits
  54. GRB050908 : Swift-XRT refined analysis
  55. GRB 050908: Swift-BAT refined analysis
  56. GRB 050908: Optical observations
  57. GRB 050908: Optical Observations
  58. GRB 050908: Swift detection of a burst
  59. GRB 050906: Optical observations at the Very Large Telescope
  60. GRB 050904 BAT refined analysis of complete data set
  61. GRB 050904: Subaru Optical Spectroscopy
  62. GRB 050906: MARGE Optical Limits
  63. GRB 050906: Swift-BAT refined analysis
  64. GRB 050906: Swift XRT upper limit
  65. GRB 050906: Radio Observations
  66. GRB 050904: Keck I-band Imaging
  67. GRB050906: P60 Observations
  68. GRB 050904: more VLT NIR observations
  69. GRB 050904: photometric redshift
  70. GRB 050904: Swift/UVOT observations
  71. GRB 050904: NIR object inside the XRT error box
  72. GRB 050904: early Swift XRT analysis results
  73. GRB 050904: SOAR YJ and PROMPT Ic Observations
  74. GRB050904: Optical Observations
  75. GRB050904: P60 Observations
  76. GRB 050904: TAROT optical limits
  77. GRB 050827 : OSN 1.5m optical observations
  78. GRB 050827: P200 NIR Observations
  79. GRB050827: Swift/UVOT upper limits
  80. GRB 050827: Optical Limit
  81. GRB 050827: XRT possible afterglow detection
  82. GRB 050826 : Lulin R band observation
  83. GRB050824: Maidanak optical limits
  84. GRB 050827: Swift-BAT refined analysis
  85. Subaru Observations of GRB050724
  86. GRB 050826: Optical Candidate
  87. GRB 050826: Swift XRT preliminary analysis results
  88. GRB 050826: BAT refined analysis
  89. GRB050826: Swift/UVOT early upper limits
  90. GRB050826: Swift-BAT detection of a long burst
  91. GRB050824: MASTER final analysis of the OT observations
  92. Swift-BAT trigger 152038 is probably not a GRB
  93. GRB 050824: XRT refined analysis and possible afterglow detection
  94. GRB 050824: BAT refined analysis of a soft weak burst
  95. GRB050824: MASTER:OT decay
  96. GRB050824: MASTER observation OT
  97. GRB050805a: MASTER optical candidat
  98. XRF050509c: Radio upper limits from GMRT
  99. GRB050822: Swift/UVOT upper limits
  100. GRB 050820A BAT observations of second, larger episode of emission

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