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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"

26325 results found.

  1. GRB 050922C: optical obserations
  2. GRB 050922C: NOT optical observations
  3. GRB 050922C: Swift detection of a bright burst
  4. GRB 050922B: ROTSE-III Optical Limits
  5. GRB 050922B,optical observation
  6. GRB050922B: Swift-BAT detection of a weak long burst
  7. GRB050820B: analysis of the XMM-Newton observation
  8. GRB050916: Swift/UVOT Upper Limits
  9. GRB 050916: Swift-BAT refined analysis
  10. Swift-BAT trigger 155764 is not a GRB
  11. Swift-BAT trigger 155764 is probably not a GRB
  12. Swift trigger 155764: bad XRT centroid
  13. Swift-BAT trigger 155535 is definitely not a GRB
  14. GRB050916 : Swift-XRT refined analysis
  15. GRB 050915B: Swift-BAT refined analysis
  16. GRB 050915B: Swift/UVOT Upper Limits
  17. GRB 050915a: IR Transient
  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: IR Observations
  22. GRB 050915: Swift XRT refined analysis
  23. GRB 050915: Swift-BAT refined analysis
  24. GRB 050915: Swift detection of a GRB
  25. GRB050911: Upper limit on X-ray afterglow
  26. Swift-BAT trigger 155072 ground analysis
  27. Swift-BAT trigger 155072 is probably not a GRB
  28. GRB 050908: DEIMOS spectrum and further analysis
  29. GRB 050911, optical content of Swift/XRT error box
  30. GRB 050911: Swift-BAT refined analysis
  31. GRB 050911: z~0.16 cluster in the field
  32. GRB050911: Swift-BAT detection of a long burst
  33. GRB 050910a: TAROT early optical limits
  34. WIRO observations in I of GRB 050908
  35. GRB 050906: Possible X-ray Counterpart
  36. GRB050908: Swift/UVOT Early upper limits
  37. GRB050908 : Swift-XRT refined analysis
  38. GRB 050908: Swift-BAT refined analysis
  39. GRB 050908: Optical observations
  40. GRB 050908: Optical Observations
  41. GRB 050908: Swift detection of a burst
  42. GRB 050906: Optical observations at the Very Large Telescope
  43. GRB 050904 BAT refined analysis of complete data set
  44. GRB 050904: Subaru Optical Spectroscopy
  45. GRB 050906: MARGE Optical Limits
  46. GRB 050906: Swift-BAT refined analysis
  47. GRB 050906: Swift XRT upper limit
  48. GRB 050906: Radio Observations
  49. GRB 050904: Keck I-band Imaging
  50. GRB050906: P60 Observations
  51. GRB 050904: more VLT NIR observations
  52. GRB 050904: photometric redshift
  53. GRB 050904: Swift/UVOT observations
  54. GRB 050904: NIR object inside the XRT error box
  55. GRB 050904: early Swift XRT analysis results
  56. GRB 050904: SOAR YJ and PROMPT Ic Observations
  57. GRB050904: Optical Observations
  58. GRB050904: P60 Observations
  59. GRB 050904: TAROT optical limits
  60. GRB 050827 : OSN 1.5m optical observations
  61. GRB 050827: P200 NIR Observations
  62. GRB050827: Swift/UVOT upper limits
  63. GRB 050827: Optical Limit
  64. GRB 050827: XRT possible afterglow detection
  65. GRB 050826 : Lulin R band observation
  66. GRB050824: Maidanak optical limits
  67. GRB 050827: Swift-BAT refined analysis
  68. Subaru Observations of GRB050724
  69. GRB 050826: Optical Candidate
  70. GRB 050826: Swift XRT preliminary analysis results
  71. GRB 050826: BAT refined analysis
  72. GRB050826: Swift/UVOT early upper limits
  73. GRB050826: Swift-BAT detection of a long burst
  74. GRB050824: MASTER final analysis of the OT observations
  75. Swift-BAT trigger 152038 is probably not a GRB
  76. GRB 050824: XRT refined analysis and possible afterglow detection
  77. GRB 050824: BAT refined analysis of a soft weak burst
  78. GRB050824: MASTER:OT decay
  79. GRB050824: MASTER observation OT
  80. GRB050805a: MASTER optical candidat
  81. XRF050509c: Radio upper limits from GMRT
  82. GRB050822: Swift/UVOT upper limits
  83. GRB 050820A BAT observations of second, larger episode of emission
  84. GRB050813: Maidanak I-band observations
  85. GRB 050822: Swift-BAT refined analysis
  86. GRB050525, GRB050607, GRB050802 BVRcIc field photometry
  87. GRB050820B at FRAM
  88. Swift/UVOT UV Photometry of GRB 050820B
  89. GRB 050822: Swift detection of a long burst
  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. GRB050820: refined XRT analysis
  96. GRB 050820 Swift-BAT refined analysis
  97. GRB050819: refined XRT analysis
  98. GRB 050820: Swift detection of a GRB
  99. GRB 050819 Swift-BAT refined analysis
  100. GRB050819: Swift-BAT detection of a weak burst

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