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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"

19531 results found.

  1. GRB050915, optical observations
  2. GRB050915: XRT position
  3. GRB 050915: ROTSE-III optical limits
  4. GRB 050915: Swift detection of a GRB
  5. GRB050911: Upper limit on X-ray afterglow
  6. Swift-BAT trigger 155072 ground analysis
  7. Swift-BAT trigger 155072 is probably not a GRB
  8. GRB050914: XRT position probably due to cosmic ray
  9. Swift is in normal operation
  10. GRB050911: Swift UVOT followup observations
  11. GRB 050911, optical content of Swift/XRT error box
  12. GRB050911: Swift-XRT position
  13. GRB 050911, optical observations
  14. GRB 050911: Swift-BAT refined analysis
  15. Later Swift-BAT triggers 154632 and 154633 RETRACTION
  16. GRB050911: Swift-BAT detection of a long burst
  17. GRB050908: detection of Swift/UVOT optical counterpart
  18. RBO GRB 050908 observations
  19. WIRO observations in I of GRB 050908
  20. GRB 050906: Possible X-ray Counterpart
  21. GRB050908: Swift/UVOT Early upper limits
  22. GRB050908 : Swift-XRT refined analysis
  23. GRB 050908: Swift-BAT refined analysis
  24. GRB 050908: Optical observations
  25. Gemini Spectroscopy of GRB 050908
  26. GRB 050908 : Swift XRT position
  27. GRB 050908: KAIT observations
  28. GRB 050908: P60 Confirmation of Optical Afterglow
  29. GRB 050908: Swift detection of a burst
  30. Swift trigger 154073 is not a GRB
  31. GRB050904: CrAO optical observations
  32. GRB 050904 BAT refined analysis of complete data set
  33. GRB 050906: MARGE Optical Limits
  34. GRB 050906: Swift-BAT refined analysis
  35. GRB 050906: Swift XRT upper limit
  36. GRB050906: P60 Observations
  37. GRB 050904: Did SWIFT/XRT see the prompt GRB emission ?
  38. GRB 050906: Bright galaxy in BAT error box
  39. GRB 050906: Swift/BAT Detection of a possible burst
  40. GRB 050904: Swift/UVOT observations
  41. GRB 050904: early Swift XRT analysis results
  42. GRB 050904: BAT refined analysis of partial data set
  43. GRB050904: P60 Observations
  44. GRB 050904: TAROT optical limits
  45. GRB050904: Swift-BAT detection of a probable burst
  46. Swift-BAT triggers 153461-153465 are not GRBs
  47. Retraction of Swift-BAT trigger #153355
  48. GRB 050824: MDM Observations
  49. GRB 050827: Swift XRT preliminary analysis results
  50. Swift Trigger #152652 is not a GRB
  51. GRB050827: Swift/UVOT upper limits
  52. GRB 050827: Optical Limit
  53. GRB 050827: XRT possible afterglow detection
  54. GRB050827: RTT150 optical observations
  55. GRB 050827: Swift-BAT refined analysis
  56. GRB050827: Swift-BAT detection of a burst
  57. GRB 050826: Optical Candidate
  58. GRB050824, HETE-2 Observation
  59. GRB 050826: Swift XRT preliminary analysis results
  60. GRB 050826: BAT refined analysis
  61. GRB050826: Swift/UVOT early upper limits
  62. GRB050824: First 2 hours of power low optical decay?
  63. GRB 050826: Swift XRT position
  64. GRB050826: Swift-BAT detection of a long burst
  65. GRB050824: MASTER final analysis of the OT observations
  66. Possible GRB050825:MASTER optical observations
  67. Swift-BAT trigger 152038 is definitely not a GRB
  68. GRB050824: CORRECTION to UVOT observing times
  69. Swift-BAT trigger 152038 is probably not a GRB
  70. GRB050824: Swift/UVOT detection of fading afterglow
  71. GRB050824: decay of the XRT light curve and updated X-ray spectrum
  72. GRB050824, I-band imaging
  73. GRB 050822: refined XRT analysis
  74. GRB 050824: XRT refined analysis and possible afterglow detection
  75. GRB 050824: BAT refined analysis of a soft weak burst
  76. GRB050824: MASTER:OT decay
  77. GRB050824: MASTER observation OT
  78. GRB050805a: MASTER optical candidat
  79. GRB 050824: ROTSE-III Optical Limits
  80. GRB050824: Swift-BAT detection of a burst
  81. GRB050822: Swift/UVOT upper limits
  82. GRB 050820A BAT observations of second, larger episode of emission
  83. GRB 050822: Swift-BAT refined analysis
  84. GRB 050820a - corrections to GCN 3846
  85. Swift/UVOT UV Photometry of GRB 050820B
  86. GRB 050822: ROTSE-III Prompt Optical Limits
  87. GRB 050822: Swift detection of a long burst
  88. Correction to Eiso calculation in GCN 3835 on GRB 050820A
  89. GRB050825a - very long GRB like GRB041219a? (Konus-Wind observation)
  90. GRB050820a BVRcIc field photometry
  91. GRB050820B XMM-Newton observation
  92. GRB 050820a: NIR Observations by WIRO
  93. GRB 050820B: Swift XRT position
  94. GRB050820B: Refined analysis of the Swift-BAT burst
  95. GRB050820B: BAT-Swift detection of a bright GRB
  96. Swift/UVOT photometry of GRB050820
  97. GRB050820: refined XRT analysis
  98. GRB 050820: Early RAPTOR detections
  99. GRB 050820 Swift-BAT refined analysis
  100. GRB050819: refined XRT analysis

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