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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"

33833 results found.

  1. GRB 050915B: XRT position
  2. GRB 050915b, SMARTS optical/IR observations
  3. GRB 050915: KAIT optical limit
  4. GRB 050915: IR Observations
  5. GRB 050915: Swift XRT refined analysis
  6. GRB 050915: Swift-BAT refined analysis
  7. GRB050915: P60 Optical Observations
  8. GRB 050915: ROTSE-III optical limits
  9. GRB 050915: Swift detection of a GRB
  10. GRB050911: Upper limit on X-ray afterglow
  11. Swift-BAT trigger 155072 ground analysis
  12. Swift-BAT trigger 155072 is probably not a GRB
  13. GRB 050911: LCO limits on a variable source
  14. GRB 050908: DEIMOS spectrum and further analysis
  15. Swift is in normal operation
  16. GRB 050911, optical content of Swift/XRT error box
  17. GRB 050911: LCO observations
  18. GRB 050911, optical observations
  19. GRB 050911: Swift-BAT refined analysis
  20. Later Swift-BAT triggers 154632 and 154633 RETRACTION
  21. GRB 050911: z~0.16 cluster in the field
  22. GRB 050910a: TAROT early optical limits
  23. RBO GRB 050908 observations
  24. WIRO observations in I of GRB 050908
  25. GRB 050906: Possible X-ray Counterpart
  26. GRB 050906: RTT150 optical observations
  27. GRB050908: VLT R-band decay index.
  28. GRB 050908: Swift-BAT refined analysis
  29. GRB 050908: Optical observations
  30. Gemini Spectroscopy of GRB 050908
  31. GRB 050908: spectroscopic redshift
  32. GRB 050908: Prompt PROMPT Observations
  33. GRB 050908 : Swift XRT position
  34. GRB 050908: KAIT observations
  35. GRB 050908: P60 Confirmation of Optical Afterglow
  36. GRB 050908: Optical Observations
  37. GRB 050908: Swift detection of a burst
  38. Swift trigger 154073 is not a GRB
  39. GRB 050906: Optical observations at the Very Large Telescope
  40. GRB050904: CrAO optical observations
  41. GRB 050904 BAT refined analysis of complete data set
  42. GRB 050904: Subaru Optical Spectroscopy
  43. GRB 050906: MARGE Optical Limits
  44. GRB 050906: Swift-BAT refined analysis
  45. GRB 050906: Swift XRT upper limit
  46. GRB 050906: Radio Observations
  47. GRB 050904: Keck I-band Imaging
  48. GRB 050904: more VLT NIR observations
  49. GRB 050904: BOOTES early R-band observation
  50. GRB 050904: Did SWIFT/XRT see the prompt GRB emission ?
  51. GRB 050906: Bright galaxy in BAT error box
  52. GRB 050906: Swift/BAT Detection of a possible burst
  53. GRB 050904: More SOAR
  54. GRB 050904: photometric redshift
  55. GRB 050904: Swift/UVOT observations
  56. GRB 050904: Afterglow Astrometry
  57. GRB 050904: NIR object inside the XRT error box
  58. GRB 050904: early Swift XRT analysis results
  59. GRB 050904: SOAR YJ and PROMPT Ic Observations
  60. GRB 050904: BAT refined analysis of partial data set
  61. GRB 050904: TAROT optical measurements
  62. GRB050904: Optical Observations
  63. GRB 050904: Environmental Constraints
  64. GRB 050904: Possible High-Redshift GRB
  65. GRB 050904: SOAR/PROMPT Observations
  66. GRB 050904: TAROT optical limits
  67. Swift-BAT triggers 153461-153465 are not GRBs
  68. GRB 050824: MDM Observations
  69. GRB 050827: Swift XRT preliminary analysis results
  70. IBAS Alerts 2641 and 2642: not a real GRB
  71. Swift Trigger #152652 is not a GRB
  72. GRB 050827 : OSN 1.5m optical observations
  73. GRB 050827: P200 NIR Observations
  74. GRB 050827: Optical Limit
  75. GRB 050827: XRT possible afterglow detection
  76. GRB 050826 : Lulin R band observation
  77. GRB050824: Maidanak optical limits
  78. GRB050820A: RTT150 optical observations
  79. GRB050827: RTT150 optical observations
  80. GRB 050827: Swift-BAT refined analysis
  81. GRB 050826: Optical Candidate
  82. GRB050824, HETE-2 Observation
  83. GRB 050826: Swift XRT preliminary analysis results
  84. GRB 050826: BAT refined analysis
  85. GRB050824: First 2 hours of power low optical decay?
  86. GRB 050826: Swift XRT position
  87. GRB050826: Swift-BAT detection of a long burst
  88. GRB050824: MASTER final analysis of the OT observations
  89. Possible GRB050825:MASTER optical observations
  90. Swift-BAT trigger 152038 is definitely not a GRB
  91. Swift-BAT trigger 152038 is probably not a GRB
  92. GRB050824: decay of the XRT light curve and updated X-ray spectrum
  93. GRB050824, I-band imaging
  94. GRB050824: Radio Observations
  95. GRB 050824: Spectroscopic redshift from the VLT
  96. GRB 050822: refined XRT analysis
  97. GRB 050824: XRT refined analysis and possible afterglow detection
  98. GRB 050824: BAT refined analysis of a soft weak burst
  99. GRB050824: MASTER:OT decay
  100. GRB050824: MASTER observation OT

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