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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"

45635 results found.

  1. GRB/SGR 050925: IR Observations
  2. GRB050922C - Swift UVOT preliminary analysis
  3. GRB 050922C: break in the lightcurve
  4. GRB 050925: WSRT Radio Observations
  5. GRB050925: Swift UVOT upper limits
  6. Refined analysis of the Swift-BAT soft short burst
  7. GRB 050925 : I-band observation at Xinglong observatory
  8. GRB050925: Faulkes Telescope North R-band limit
  9. GRB050925: Swift-BAT detection of a short burst
  10. GRB 050922B: Correction to BAT refined analysis, longer burst
  11. GRB050922C: TNG spectroscopic observations
  12. GRB050922B: refined XRT analysis
  13. Konus-Wind observation of GRB 050922C
  14. GRB 050922C: Refined redshift
  15. GRB050922B: Swift UVOT early upper limits.
  16. GRB OT observation
  17. GRB050922C: observation at MonteBoo
  18. INT 2.5m limit for GRB050922B
  19. GRB 050922B: optical limit
  20. GRB050922C: Optical Observations
  21. GRB 050922C: Swift XRT refined analysis
  22. HETE Fregate observations of GRB 050922C
  23. GRB 050922C: Swift-BAT refined analysis
  24. GRB 050922B: Swift-BAT refined analysis
  25. GRB050922C: optical observations
  26. GRB 050922C: Absorption redshift from the Nordic Optical Telescope
  27. GRB 050922C: optical obserations
  28. GRB 050922C: NOT optical observations
  29. GRB 050922A: Analysis of Swift/XRT TOO observation
  30. GRB 050922C: Swift detection of a bright burst
  31. GRB 050922C: ROTSE-IIId Refined Analysis
  32. GRB 050922C: ROTSE-III Detection of Possible Counterpart
  33. GRB 050922B: ROTSE-III Optical Limits
  34. GRB 050922B,optical observation
  35. GRB050922B: Swift-BAT detection of a weak long burst
  36. Possible GRB 050922 detected by INTEGRAL
  37. GRB050918: Possible Swift/XRT detected afterglow
  38. GRB050820B: analysis of the XMM-Newton observation
  39. GRB050916: Swift/UVOT Upper Limits
  40. GRB 050916: Swift-BAT refined analysis
  41. GRB 050918 - A long GRB detected by INTEGRAL
  42. GRB 050915a: Radio Observations
  43. Swift-BAT trigger 155764 is not a GRB
  44. Swift-BAT trigger 155764 is probably not a GRB
  45. Swift trigger 155764: bad XRT centroid
  46. Swift-BAT trigger 155535 is definitely not a GRB
  47. GRB050916 : Swift-XRT refined analysis
  48. GRB 050916: XRT position
  49. GRB 050915b, SMARTS optical/IR observations of the XRT position
  50. GRB 050915B: Swift-BAT refined analysis
  51. GRB 050915B: Swift/UVOT Upper Limits
  52. GRB050916: Swift-BAT detection of a long weak burst
  53. GRB 050915a: IR Transient
  54. GRB 050915B: XRT position
  55. GRB 050915b, SMARTS optical/IR observations
  56. GRB050915B: Swift-BAT detection of a long bright burst
  57. GRB050915: Swift/UVOT upper limits
  58. GRB 050915: KAIT optical limit
  59. GRB 050915: IR Observations
  60. GRB 050915: Swift XRT refined analysis
  61. GRB 050915: Swift-BAT refined analysis
  62. GRB050915: P60 Optical Observations
  63. GRB050915, optical observations
  64. GRB050915: XRT position
  65. GRB 050915: ROTSE-III optical limits
  66. GRB 050915: Swift detection of a GRB
  67. GRB050911: Upper limit on X-ray afterglow
  68. Swift-BAT trigger 155072 ground analysis
  69. Swift-BAT trigger 155072 is probably not a GRB
  70. GRB050914: XRT position probably due to cosmic ray
  71. GRB 050911: LCO limits on a variable source
  72. GRB 050908: DEIMOS spectrum and further analysis
  73. Swift is in normal operation
  74. GRB050911: Swift UVOT followup observations
  75. GRB 050911, optical content of Swift/XRT error box
  76. GRB050911: Swift-XRT position
  77. GRB 050911: LCO observations
  78. GRB 050911, optical observations
  79. GRB 050911: Swift-BAT refined analysis
  80. Later Swift-BAT triggers 154632 and 154633 RETRACTION
  81. GRB 050911: z~0.16 cluster in the field
  82. GRB050911: Swift-BAT detection of a long burst
  83. GRB050908: detection of Swift/UVOT optical counterpart
  84. GRB 050910a: TAROT early optical limits
  85. RBO GRB 050908 observations
  86. WIRO observations in I of GRB 050908
  87. GRB 050906: Possible X-ray Counterpart
  88. GRB 050906: RTT150 optical observations
  89. GRB050908: Swift/UVOT Early upper limits
  90. GRB050908: VLT R-band decay index.
  91. GRB050908 : Swift-XRT refined analysis
  92. GRB 050908: Swift-BAT refined analysis
  93. GRB 050908: Optical observations
  94. Gemini Spectroscopy of GRB 050908
  95. GRB 050908: spectroscopic redshift
  96. GRB 050908: Prompt PROMPT Observations
  97. GRB 050908 : Swift XRT position
  98. GRB 050908: KAIT observations
  99. GRB 050908: P60 Confirmation of Optical Afterglow
  100. GRB 050908: Optical Observations

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