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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"

45463 results found.

  1. GRB 050922A: Analysis of Swift/XRT TOO observation
  2. GRB 050922C: Swift detection of a bright burst
  3. GRB 050922C: ROTSE-IIId Refined Analysis
  4. GRB 050922C: ROTSE-III Detection of Possible Counterpart
  5. GRB 050922B: ROTSE-III Optical Limits
  6. GRB 050922B,optical observation
  7. GRB050922B: Swift-BAT detection of a weak long burst
  8. Possible GRB 050922 detected by INTEGRAL
  9. GRB050918: Possible Swift/XRT detected afterglow
  10. GRB050820B: analysis of the XMM-Newton observation
  11. GRB050916: Swift/UVOT Upper Limits
  12. GRB 050916: Swift-BAT refined analysis
  13. GRB 050918 - A long GRB detected by INTEGRAL
  14. GRB 050915a: Radio Observations
  15. Swift-BAT trigger 155764 is not a GRB
  16. Swift-BAT trigger 155764 is probably not a GRB
  17. Swift trigger 155764: bad XRT centroid
  18. Swift-BAT trigger 155535 is definitely not a GRB
  19. GRB050916 : Swift-XRT refined analysis
  20. GRB 050916: XRT position
  21. GRB 050915b, SMARTS optical/IR observations of the XRT position
  22. GRB 050915B: Swift-BAT refined analysis
  23. GRB 050915B: Swift/UVOT Upper Limits
  24. GRB050916: Swift-BAT detection of a long weak burst
  25. GRB 050915a: IR Transient
  26. GRB 050915B: XRT position
  27. GRB 050915b, SMARTS optical/IR observations
  28. GRB050915B: Swift-BAT detection of a long bright burst
  29. GRB050915: Swift/UVOT upper limits
  30. GRB 050915: KAIT optical limit
  31. GRB 050915: IR Observations
  32. GRB 050915: Swift XRT refined analysis
  33. GRB 050915: Swift-BAT refined analysis
  34. GRB050915: P60 Optical Observations
  35. GRB050915, optical observations
  36. GRB050915: XRT position
  37. GRB 050915: ROTSE-III optical limits
  38. GRB 050915: Swift detection of a GRB
  39. GRB050911: Upper limit on X-ray afterglow
  40. Swift-BAT trigger 155072 ground analysis
  41. Swift-BAT trigger 155072 is probably not a GRB
  42. GRB050914: XRT position probably due to cosmic ray
  43. GRB 050911: LCO limits on a variable source
  44. GRB 050908: DEIMOS spectrum and further analysis
  45. Swift is in normal operation
  46. GRB050911: Swift UVOT followup observations
  47. GRB 050911, optical content of Swift/XRT error box
  48. GRB050911: Swift-XRT position
  49. GRB 050911: LCO observations
  50. GRB 050911, optical observations
  51. GRB 050911: Swift-BAT refined analysis
  52. Later Swift-BAT triggers 154632 and 154633 RETRACTION
  53. GRB 050911: z~0.16 cluster in the field
  54. GRB050911: Swift-BAT detection of a long burst
  55. GRB050908: detection of Swift/UVOT optical counterpart
  56. GRB 050910a: TAROT early optical limits
  57. RBO GRB 050908 observations
  58. WIRO observations in I of GRB 050908
  59. GRB 050906: Possible X-ray Counterpart
  60. GRB 050906: RTT150 optical observations
  61. GRB050908: Swift/UVOT Early upper limits
  62. GRB050908: VLT R-band decay index.
  63. GRB050908 : Swift-XRT refined analysis
  64. GRB 050908: Swift-BAT refined analysis
  65. GRB 050908: Optical observations
  66. Gemini Spectroscopy of GRB 050908
  67. GRB 050908: spectroscopic redshift
  68. GRB 050908: Prompt PROMPT Observations
  69. GRB 050908 : Swift XRT position
  70. GRB 050908: KAIT observations
  71. GRB 050908: P60 Confirmation of Optical Afterglow
  72. GRB 050908: Optical Observations
  73. GRB 050908: Swift detection of a burst
  74. Swift trigger 154073 is not a GRB
  75. GRB 050906: Optical observations at the Very Large Telescope
  76. GRB050904: CrAO optical observations
  77. GRB 050904 BAT refined analysis of complete data set
  78. GRB 050904: Subaru Optical Spectroscopy
  79. GRB 050906: MARGE Optical Limits
  80. GRB 050906: Swift-BAT refined analysis
  81. GRB 050906: Swift XRT upper limit
  82. GRB 050906: Radio Observations
  83. GRB 050904: Keck I-band Imaging
  84. GRB050906: P60 Observations
  85. GRB 050904: more VLT NIR observations
  86. GRB 050904: BOOTES early R-band observation
  87. GRB 050904: Did SWIFT/XRT see the prompt GRB emission ?
  88. GRB 050906: Bright galaxy in BAT error box
  89. GRB 050906: Swift/BAT Detection of a possible burst
  90. GRB 050904: More SOAR
  91. GRB 050904: photometric redshift
  92. GRB 050904: Swift/UVOT observations
  93. GRB 050904: Afterglow Astrometry
  94. GRB 050904: NIR object inside the XRT error box
  95. GRB 050904: early Swift XRT analysis results
  96. GRB 050904: SOAR YJ and PROMPT Ic Observations
  97. GRB 050904: BAT refined analysis of partial data set
  98. GRB 050904: TAROT optical measurements
  99. GRB050904: Optical Observations
  100. GRB 050904: Environmental Constraints

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