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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"

36053 results found.

  1. GRB 050922C: Swift detection of a bright burst
  2. GRB 050922C: ROTSE-IIId Refined Analysis
  3. GRB 050922C: ROTSE-III Detection of Possible Counterpart
  4. GRB 050922B: ROTSE-III Optical Limits
  5. GRB 050922B,optical observation
  6. GRB050922B: Swift-BAT detection of a weak long burst
  7. Possible GRB 050922 detected by INTEGRAL
  8. GRB050820B: analysis of the XMM-Newton observation
  9. GRB050916: Swift/UVOT Upper Limits
  10. GRB 050916: Swift-BAT refined analysis
  11. GRB 050918 - A long GRB detected by INTEGRAL
  12. GRB 050915a: Radio Observations
  13. Swift-BAT trigger 155764 is not a GRB
  14. Swift-BAT trigger 155764 is probably not a GRB
  15. Swift-BAT trigger 155535 is definitely not a GRB
  16. GRB 050916: XRT position
  17. GRB 050915b, SMARTS optical/IR observations of the XRT position
  18. GRB 050915B: Swift-BAT refined analysis
  19. GRB 050915B: Swift/UVOT Upper Limits
  20. GRB 050915a: IR Transient
  21. GRB 050915B: XRT position
  22. GRB 050915b, SMARTS optical/IR observations
  23. GRB 050915: KAIT optical limit
  24. GRB 050915: IR Observations
  25. GRB 050915: Swift XRT refined analysis
  26. GRB 050915: Swift-BAT refined analysis
  27. GRB050915: P60 Optical Observations
  28. GRB 050915: ROTSE-III optical limits
  29. GRB 050915: Swift detection of a GRB
  30. GRB050911: Upper limit on X-ray afterglow
  31. Swift-BAT trigger 155072 ground analysis
  32. Swift-BAT trigger 155072 is probably not a GRB
  33. GRB 050911: LCO limits on a variable source
  34. GRB 050908: DEIMOS spectrum and further analysis
  35. Swift is in normal operation
  36. GRB 050911, optical content of Swift/XRT error box
  37. GRB 050911: LCO observations
  38. GRB 050911, optical observations
  39. GRB 050911: Swift-BAT refined analysis
  40. Later Swift-BAT triggers 154632 and 154633 RETRACTION
  41. GRB 050911: z~0.16 cluster in the field
  42. GRB 050910a: TAROT early optical limits
  43. RBO GRB 050908 observations
  44. WIRO observations in I of GRB 050908
  45. GRB 050906: Possible X-ray Counterpart
  46. GRB 050906: RTT150 optical observations
  47. GRB050908: VLT R-band decay index.
  48. GRB 050908: Swift-BAT refined analysis
  49. GRB 050908: Optical observations
  50. Gemini Spectroscopy of GRB 050908
  51. GRB 050908: spectroscopic redshift
  52. GRB 050908: Prompt PROMPT Observations
  53. GRB 050908 : Swift XRT position
  54. GRB 050908: KAIT observations
  55. GRB 050908: P60 Confirmation of Optical Afterglow
  56. GRB 050908: Optical Observations
  57. GRB 050908: Swift detection of a burst
  58. Swift trigger 154073 is not a GRB
  59. GRB 050906: Optical observations at the Very Large Telescope
  60. GRB050904: CrAO optical observations
  61. GRB 050904 BAT refined analysis of complete data set
  62. GRB 050904: Subaru Optical Spectroscopy
  63. GRB 050906: MARGE Optical Limits
  64. GRB 050906: Swift-BAT refined analysis
  65. GRB 050906: Swift XRT upper limit
  66. GRB 050906: Radio Observations
  67. GRB 050904: Keck I-band Imaging
  68. GRB 050904: more VLT NIR observations
  69. GRB 050904: BOOTES early R-band observation
  70. GRB 050904: Did SWIFT/XRT see the prompt GRB emission ?
  71. GRB 050906: Bright galaxy in BAT error box
  72. GRB 050906: Swift/BAT Detection of a possible burst
  73. GRB 050904: More SOAR
  74. GRB 050904: photometric redshift
  75. GRB 050904: Swift/UVOT observations
  76. GRB 050904: Afterglow Astrometry
  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. GRB 050904: BAT refined analysis of partial data set
  81. GRB 050904: TAROT optical measurements
  82. GRB050904: Optical Observations
  83. GRB 050904: Environmental Constraints
  84. GRB 050904: Possible High-Redshift GRB
  85. GRB 050904: SOAR/PROMPT Observations
  86. GRB 050904: TAROT optical limits
  87. Swift-BAT triggers 153461-153465 are not GRBs
  88. GRB 050824: MDM Observations
  89. GRB 050827: Swift XRT preliminary analysis results
  90. IBAS Alerts 2641 and 2642: not a real GRB
  91. Swift Trigger #152652 is not a GRB
  92. GRB 050827 : OSN 1.5m optical observations
  93. GRB 050827: P200 NIR Observations
  94. GRB 050827: Optical Limit
  95. GRB 050827: XRT possible afterglow detection
  96. GRB 050826 : Lulin R band observation
  97. GRB050824: Maidanak optical limits
  98. GRB050820A: RTT150 optical observations
  99. GRB050827: RTT150 optical observations
  100. GRB 050827: Swift-BAT refined analysis

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