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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"

42173 results found.

  1. GRB 050922B: ROTSE-III Optical Limits
  2. GRB 050922B,optical observation
  3. GRB050922B: Swift-BAT detection of a weak long burst
  4. Possible GRB 050922 detected by INTEGRAL
  5. GRB050918: Possible Swift/XRT detected afterglow
  6. GRB050820B: analysis of the XMM-Newton observation
  7. GRB 050918 - A long GRB detected by INTEGRAL
  8. Swift-BAT trigger 155764 is probably not a GRB
  9. Swift-BAT trigger 155535 is definitely not a GRB
  10. GRB050916 : Swift-XRT refined analysis
  11. GRB 050916: XRT position
  12. GRB 050915b, SMARTS optical/IR observations of the XRT position
  13. GRB 050915B: Swift-BAT refined analysis
  14. GRB 050915B: Swift/UVOT Upper Limits
  15. GRB050916: Swift-BAT detection of a long weak burst
  16. GRB 050915a: IR Transient
  17. GRB 050915B: XRT position
  18. GRB 050915b, SMARTS optical/IR observations
  19. GRB050915B: Swift-BAT detection of a long bright burst
  20. GRB050915: Swift/UVOT upper limits
  21. GRB 050915: KAIT optical limit
  22. GRB 050915: IR Observations
  23. GRB 050915: Swift XRT refined analysis
  24. GRB050915: P60 Optical Observations
  25. GRB050915, optical observations
  26. GRB050915: XRT position
  27. GRB 050915: ROTSE-III optical limits
  28. GRB 050915: Swift detection of a GRB
  29. GRB050911: Upper limit on X-ray afterglow
  30. Swift-BAT trigger 155072 ground analysis
  31. Swift-BAT trigger 155072 is probably not a GRB
  32. GRB050914: XRT position probably due to cosmic ray
  33. GRB 050911: LCO limits on a variable source
  34. GRB 050908: DEIMOS spectrum and further analysis
  35. GRB050911: Swift UVOT followup observations
  36. GRB 050911, optical content of Swift/XRT error box
  37. GRB050911: Swift-XRT position
  38. GRB 050911: LCO observations
  39. GRB 050911, optical observations
  40. GRB 050911: Swift-BAT refined analysis
  41. GRB 050911: z~0.16 cluster in the field
  42. GRB050911: Swift-BAT detection of a long burst
  43. GRB050908: detection of Swift/UVOT optical counterpart
  44. GRB 050910a: TAROT early optical limits
  45. RBO GRB 050908 observations
  46. WIRO observations in I of GRB 050908
  47. GRB 050906: Possible X-ray Counterpart
  48. GRB 050906: RTT150 optical observations
  49. GRB050908: Swift/UVOT Early upper limits
  50. GRB050908: VLT R-band decay index.
  51. GRB050908 : Swift-XRT refined analysis
  52. GRB 050908: Swift-BAT refined analysis
  53. GRB 050908: Optical observations
  54. Gemini Spectroscopy of GRB 050908
  55. GRB 050908: spectroscopic redshift
  56. GRB 050908 : Swift XRT position
  57. GRB 050908: KAIT observations
  58. GRB 050908: P60 Confirmation of Optical Afterglow
  59. GRB 050908: Optical Observations
  60. GRB 050908: Swift detection of a burst
  61. Swift trigger 154073 is not a GRB
  62. GRB 050906: Optical observations at the Very Large Telescope
  63. GRB050904: CrAO optical observations
  64. GRB 050904 BAT refined analysis of complete data set
  65. GRB 050904: Subaru Optical Spectroscopy
  66. GRB 050906: MARGE Optical Limits
  67. GRB 050906: Swift-BAT refined analysis
  68. GRB 050906: Swift XRT upper limit
  69. GRB 050904: Keck I-band Imaging
  70. GRB 050904: more VLT NIR observations
  71. GRB 050904: BOOTES early R-band observation
  72. GRB 050904: Did SWIFT/XRT see the prompt GRB emission ?
  73. GRB 050906: Swift/BAT Detection of a possible burst
  74. GRB 050904: More SOAR
  75. GRB 050904: photometric redshift
  76. GRB 050904: Swift/UVOT observations
  77. GRB 050904: Afterglow Astrometry
  78. GRB 050904: NIR object inside the XRT error box
  79. GRB 050904: early Swift XRT analysis results
  80. GRB 050904: SOAR YJ and PROMPT Ic Observations
  81. GRB 050904: BAT refined analysis of partial data set
  82. GRB 050904: TAROT optical measurements
  83. GRB050904: Optical Observations
  84. GRB 050904: Environmental Constraints
  85. GRB 050904: Possible High-Redshift GRB
  86. GRB 050904: SOAR/PROMPT Observations
  87. GRB050904: P60 Observations
  88. GRB 050904: TAROT optical limits
  89. GRB050904: Swift-BAT detection of a probable burst
  90. Retraction of Swift-BAT trigger #153355
  91. GRB 050824: MDM Observations
  92. GRB 050827: Swift XRT preliminary analysis results
  93. GRB 050827 : OSN 1.5m optical observations
  94. GRB 050827: P200 NIR Observations
  95. GRB050827: Swift/UVOT upper limits
  96. GRB 050827: Optical Limit
  97. GRB 050827: XRT possible afterglow detection
  98. GRB 050826 : Lulin R band observation
  99. GRB050824: Maidanak optical limits
  100. GRB050820A: RTT150 optical observations

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