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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"

26050 results found.

  1. GRB 050911: LCO limits on a variable source
  2. GRB 050908: DEIMOS spectrum and further analysis
  3. Swift is in normal operation
  4. GRB050911: Swift UVOT followup observations
  5. GRB 050911, optical content of Swift/XRT error box
  6. GRB050911: Swift-XRT position
  7. GRB 050911, optical observations
  8. GRB 050911: Swift-BAT refined analysis
  9. Later Swift-BAT triggers 154632 and 154633 RETRACTION
  10. GRB050911: Swift-BAT detection of a long burst
  11. GRB050908: detection of Swift/UVOT optical counterpart
  12. GRB 050910a: TAROT early optical limits
  13. RBO GRB 050908 observations
  14. WIRO observations in I of GRB 050908
  15. GRB 050906: Possible X-ray Counterpart
  16. GRB050908: Swift/UVOT Early upper limits
  17. GRB050908: VLT R-band decay index.
  18. GRB050908 : Swift-XRT refined analysis
  19. GRB 050908: Swift-BAT refined analysis
  20. GRB 050908: Optical observations
  21. Gemini Spectroscopy of GRB 050908
  22. GRB 050908: spectroscopic redshift
  23. GRB 050908: Prompt PROMPT Observations
  24. GRB 050908 : Swift XRT position
  25. GRB 050908: KAIT observations
  26. GRB 050908: P60 Confirmation of Optical Afterglow
  27. GRB 050908: Swift detection of a burst
  28. Swift trigger 154073 is not a GRB
  29. GRB050904: CrAO optical observations
  30. GRB 050904 BAT refined analysis of complete data set
  31. GRB 050904: Subaru Optical Spectroscopy
  32. GRB 050906: MARGE Optical Limits
  33. GRB 050906: Swift-BAT refined analysis
  34. GRB 050906: Swift XRT upper limit
  35. GRB 050904: Keck I-band Imaging
  36. GRB050906: P60 Observations
  37. GRB 050904: more VLT NIR observations
  38. GRB 050904: Did SWIFT/XRT see the prompt GRB emission ?
  39. GRB 050906: Bright galaxy in BAT error box
  40. GRB 050906: Swift/BAT Detection of a possible burst
  41. GRB 050904: More SOAR
  42. GRB 050904: photometric redshift
  43. GRB 050904: Swift/UVOT observations
  44. GRB 050904: Afterglow Astrometry
  45. GRB 050904: NIR object inside the XRT error box
  46. GRB 050904: early Swift XRT analysis results
  47. GRB 050904: SOAR YJ and PROMPT Ic Observations
  48. GRB 050904: BAT refined analysis of partial data set
  49. GRB050904: Optical Observations
  50. GRB 050904: Environmental Constraints
  51. GRB 050904: Possible High-Redshift GRB
  52. GRB 050904: SOAR/PROMPT Observations
  53. GRB050904: P60 Observations
  54. GRB 050904: TAROT optical limits
  55. GRB050904: Swift-BAT detection of a probable burst
  56. Swift-BAT triggers 153461-153465 are not GRBs
  57. Retraction of Swift-BAT trigger #153355
  58. GRB 050824: MDM Observations
  59. GRB 050827: Swift XRT preliminary analysis results
  60. Swift Trigger #152652 is not a GRB
  61. GRB 050827 : OSN 1.5m optical observations
  62. GRB 050827: P200 NIR Observations
  63. GRB050827: Swift/UVOT upper limits
  64. GRB 050827: Optical Limit
  65. GRB 050827: XRT possible afterglow detection
  66. GRB 050826 : Lulin R band observation
  67. GRB050827: RTT150 optical observations
  68. GRB 050827: Swift-BAT refined analysis
  69. GRB050827: Swift-BAT detection of a burst
  70. GRB 050826: Optical Candidate
  71. GRB050824, HETE-2 Observation
  72. GRB 050826: Swift XRT preliminary analysis results
  73. GRB 050826: BAT refined analysis
  74. GRB050826: Swift/UVOT early upper limits
  75. GRB050824: First 2 hours of power low optical decay?
  76. GRB 050826: Swift XRT position
  77. GRB050826: Swift-BAT detection of a long burst
  78. GRB050824: MASTER final analysis of the OT observations
  79. Possible GRB050825:MASTER optical observations
  80. Swift-BAT trigger 152038 is definitely not a GRB
  81. GRB050824: CORRECTION to UVOT observing times
  82. Swift-BAT trigger 152038 is probably not a GRB
  83. GRB050824: Swift/UVOT detection of fading afterglow
  84. GRB050824: decay of the XRT light curve and updated X-ray spectrum
  85. GRB050824, I-band imaging
  86. GRB050824: Radio Observations
  87. GRB 050824: Spectroscopic redshift from the VLT
  88. GRB 050822: refined XRT analysis
  89. GRB 050824: XRT refined analysis and possible afterglow detection
  90. GRB 050824: BAT refined analysis of a soft weak burst
  91. GRB050824: MASTER:OT decay
  92. GRB050824: MASTER observation OT
  93. GRB050805a: MASTER optical candidat
  94. GRB 050824: ROTSE-III Optical Limits
  95. GRB050824: Swift-BAT detection of a burst
  96. GRB050820A: RTT150 optical observations
  97. GRB050820a: PROMPT RcIc Observations
  98. GRB050815: Maidanak optical observation
  99. XRF050509c: Radio upper limits from GMRT
  100. VLT/UVES spectroscopy of GRB050820

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