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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"

26334 results found.

  1. GRB050925: Swift-BAT detection of a short burst
  2. GRB050922C: TNG spectroscopic observations
  3. GRB050922B: refined XRT analysis
  4. GRB050922B: Swift UVOT early upper limits.
  5. GRB050922C: Optical Observations
  6. GRB 050922C: Swift XRT refined analysis
  7. HETE Fregate observations of GRB 050922C
  8. GRB 050922C: Swift-BAT refined analysis
  9. GRB 050922B: Swift-BAT refined analysis
  10. GRB 050922C: optical obserations
  11. GRB 050922C: NOT optical observations
  12. GRB 050922C: Swift detection of a bright burst
  13. GRB 050922B: ROTSE-III Optical Limits
  14. GRB 050922B,optical observation
  15. GRB050922B: Swift-BAT detection of a weak long burst
  16. GRB050820B: analysis of the XMM-Newton observation
  17. GRB050916: Swift/UVOT Upper Limits
  18. GRB 050916: Swift-BAT refined analysis
  19. Swift-BAT trigger 155764 is not a GRB
  20. Swift-BAT trigger 155764 is probably not a GRB
  21. Swift trigger 155764: bad XRT centroid
  22. Swift-BAT trigger 155535 is definitely not a GRB
  23. GRB050916 : Swift-XRT refined analysis
  24. GRB 050915B: Swift-BAT refined analysis
  25. GRB 050915B: Swift/UVOT Upper Limits
  26. GRB 050915a: IR Transient
  27. GRB 050915b, SMARTS optical/IR observations
  28. GRB050915B: Swift-BAT detection of a long bright burst
  29. GRB050915: Swift/UVOT upper limits
  30. GRB 050915: IR Observations
  31. GRB 050915: Swift XRT refined analysis
  32. GRB 050915: Swift-BAT refined analysis
  33. GRB 050915: Swift detection of a GRB
  34. GRB050911: Upper limit on X-ray afterglow
  35. Swift-BAT trigger 155072 ground analysis
  36. Swift-BAT trigger 155072 is probably not a GRB
  37. GRB 050908: DEIMOS spectrum and further analysis
  38. GRB 050911, optical content of Swift/XRT error box
  39. GRB 050911: Swift-BAT refined analysis
  40. GRB 050911: z~0.16 cluster in the field
  41. GRB050911: Swift-BAT detection of a long burst
  42. GRB 050910a: TAROT early optical limits
  43. WIRO observations in I of GRB 050908
  44. GRB 050906: Possible X-ray Counterpart
  45. GRB050908: Swift/UVOT Early upper limits
  46. GRB050908 : Swift-XRT refined analysis
  47. GRB 050908: Swift-BAT refined analysis
  48. GRB 050908: Optical observations
  49. GRB 050908: Optical Observations
  50. GRB 050908: Swift detection of a burst
  51. GRB 050906: Optical observations at the Very Large Telescope
  52. GRB 050904 BAT refined analysis of complete data set
  53. GRB 050904: Subaru Optical Spectroscopy
  54. GRB 050906: MARGE Optical Limits
  55. GRB 050906: Swift-BAT refined analysis
  56. GRB 050906: Swift XRT upper limit
  57. GRB 050906: Radio Observations
  58. GRB 050904: Keck I-band Imaging
  59. GRB050906: P60 Observations
  60. GRB 050904: more VLT NIR observations
  61. GRB 050904: photometric redshift
  62. GRB 050904: Swift/UVOT observations
  63. GRB 050904: NIR object inside the XRT error box
  64. GRB 050904: early Swift XRT analysis results
  65. GRB 050904: SOAR YJ and PROMPT Ic Observations
  66. GRB050904: Optical Observations
  67. GRB050904: P60 Observations
  68. GRB 050904: TAROT optical limits
  69. GRB 050827 : OSN 1.5m optical observations
  70. GRB 050827: P200 NIR Observations
  71. GRB050827: Swift/UVOT upper limits
  72. GRB 050827: Optical Limit
  73. GRB 050827: XRT possible afterglow detection
  74. GRB 050826 : Lulin R band observation
  75. GRB050824: Maidanak optical limits
  76. GRB 050827: Swift-BAT refined analysis
  77. Subaru Observations of GRB050724
  78. GRB 050826: Optical Candidate
  79. GRB 050826: Swift XRT preliminary analysis results
  80. GRB 050826: BAT refined analysis
  81. GRB050826: Swift/UVOT early upper limits
  82. GRB050826: Swift-BAT detection of a long burst
  83. GRB050824: MASTER final analysis of the OT observations
  84. Swift-BAT trigger 152038 is probably not a GRB
  85. GRB 050824: XRT refined analysis and possible afterglow detection
  86. GRB 050824: BAT refined analysis of a soft weak burst
  87. GRB050824: MASTER:OT decay
  88. GRB050824: MASTER observation OT
  89. GRB050805a: MASTER optical candidat
  90. XRF050509c: Radio upper limits from GMRT
  91. GRB050822: Swift/UVOT upper limits
  92. GRB 050820A BAT observations of second, larger episode of emission
  93. GRB050813: Maidanak I-band observations
  94. GRB 050822: Swift-BAT refined analysis
  95. GRB050525, GRB050607, GRB050802 BVRcIc field photometry
  96. GRB050820B at FRAM
  97. Swift/UVOT UV Photometry of GRB 050820B
  98. GRB 050822: Swift detection of a long burst
  99. GRB050820a BVRcIc field photometry
  100. GRB050820B XMM-Newton observation

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