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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"

36180 results found.

  1. GRB 051001: I-band limit
  2. GRB 051001: AAT infra-red observations
  3. GRB 051001: Swift-BAT refined analysis
  4. GRB 051001: Swift Detection of a Burst
  5. GRB 051001: ROTSE-III Optical Limits
  6. GRB050908: optical observations
  7. GRB050922C: optical observation
  8. GRB050922B: optical limit
  9. GRB 050922C: further VLT observations
  10. GRB 050820A: NIR photometry at the TNG
  11. GRB050922C: UVES/VLT high resolution spectroscopy
  12. GRB050925: Swift/XRT limits
  13. GRB/SGR 050925: IR Observations
  14. GRB 050922C: break in the lightcurve
  15. GRB 050925: WSRT Radio Observations
  16. GRB 050925 : I-band observation at Xinglong observatory
  17. GRB050925: Faulkes Telescope North R-band limit
  18. GRB050925: Swift-BAT detection of a short burst
  19. GRB 050922B: Correction to BAT refined analysis, longer burst
  20. GRB050922C: TNG spectroscopic observations
  21. GRB050922B: refined XRT analysis
  22. Konus-Wind observation of GRB 050922C
  23. GRB 050922C: Refined redshift
  24. GRB OT observation
  25. GRB050922C: observation at MonteBoo
  26. INT 2.5m limit for GRB050922B
  27. GRB 050922B: optical limit
  28. GRB050922C: Optical Observations
  29. GRB 050922C: Swift XRT refined analysis
  30. HETE Fregate observations of GRB 050922C
  31. GRB 050922C: Swift-BAT refined analysis
  32. GRB 050922B: Swift-BAT refined analysis
  33. GRB 050922C: Absorption redshift from the Nordic Optical Telescope
  34. GRB 050922C: optical obserations
  35. GRB 050922C: NOT optical observations
  36. GRB 050922A: Analysis of Swift/XRT TOO observation
  37. GRB 050922C: Swift detection of a bright burst
  38. GRB 050922C: ROTSE-IIId Refined Analysis
  39. GRB 050922C: ROTSE-III Detection of Possible Counterpart
  40. GRB 050922B: ROTSE-III Optical Limits
  41. GRB 050922B,optical observation
  42. GRB050922B: Swift-BAT detection of a weak long burst
  43. Possible GRB 050922 detected by INTEGRAL
  44. GRB050820B: analysis of the XMM-Newton observation
  45. GRB050916: Swift/UVOT Upper Limits
  46. GRB 050916: Swift-BAT refined analysis
  47. GRB 050918 - A long GRB detected by INTEGRAL
  48. GRB 050915a: Radio Observations
  49. Swift-BAT trigger 155764 is not a GRB
  50. Swift-BAT trigger 155764 is probably not a GRB
  51. Swift-BAT trigger 155535 is definitely not a GRB
  52. GRB 050916: XRT position
  53. GRB 050915b, SMARTS optical/IR observations of the XRT position
  54. GRB 050915B: Swift-BAT refined analysis
  55. GRB 050915B: Swift/UVOT Upper Limits
  56. GRB 050915a: IR Transient
  57. GRB 050915B: XRT position
  58. GRB 050915b, SMARTS optical/IR observations
  59. GRB 050915: KAIT optical limit
  60. GRB 050915: IR Observations
  61. GRB 050915: Swift XRT refined analysis
  62. GRB 050915: Swift-BAT refined analysis
  63. GRB050915: P60 Optical Observations
  64. GRB 050915: ROTSE-III optical limits
  65. GRB 050915: Swift detection of a GRB
  66. GRB050911: Upper limit on X-ray afterglow
  67. Swift-BAT trigger 155072 ground analysis
  68. Swift-BAT trigger 155072 is probably not a GRB
  69. GRB 050911: LCO limits on a variable source
  70. GRB 050908: DEIMOS spectrum and further analysis
  71. Swift is in normal operation
  72. GRB 050911, optical content of Swift/XRT error box
  73. GRB 050911: LCO observations
  74. GRB 050911, optical observations
  75. GRB 050911: Swift-BAT refined analysis
  76. Later Swift-BAT triggers 154632 and 154633 RETRACTION
  77. GRB 050911: z~0.16 cluster in the field
  78. GRB 050910a: TAROT early optical limits
  79. RBO GRB 050908 observations
  80. WIRO observations in I of GRB 050908
  81. GRB 050906: Possible X-ray Counterpart
  82. GRB 050906: RTT150 optical observations
  83. GRB050908: VLT R-band decay index.
  84. GRB 050908: Swift-BAT refined analysis
  85. GRB 050908: Optical observations
  86. Gemini Spectroscopy of GRB 050908
  87. GRB 050908: spectroscopic redshift
  88. GRB 050908: Prompt PROMPT Observations
  89. GRB 050908 : Swift XRT position
  90. GRB 050908: KAIT observations
  91. GRB 050908: P60 Confirmation of Optical Afterglow
  92. GRB 050908: Optical Observations
  93. GRB 050908: Swift detection of a burst
  94. Swift trigger 154073 is not a GRB
  95. GRB 050906: Optical observations at the Very Large Telescope
  96. GRB050904: CrAO optical observations
  97. GRB 050904 BAT refined analysis of complete data set
  98. GRB 050904: Subaru Optical Spectroscopy
  99. GRB 050906: MARGE Optical Limits
  100. GRB 050906: Swift-BAT refined analysis

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