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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"

24963 results found.

  1. GRB 051006: Swift/UVOT Upper Limits
  2. GRB051008: optical candidate
  3. GRB 051008 - a low redshift low-luminosity burst?
  4. GRB051011: bright nebulae near error box
  5. GRB051011: MASTER optical observation
  6. GRB051008: Final refined analysis of the Swift-BAT burst
  7. GRB051008: Radio Observation
  8. GRB 051008, optical observations
  9. GRB 051008: early Swift XRT analysis
  10. GRB 051008: Swift UVOT Candidate
  11. GRB 051006: P60 Observations
  12. Swift-BAT trigger 158700 is a probable Cosmic Ray Shower Event
  13. GRB 051006: optical observations at Sierra Nevada
  14. GRB051006: Refined analysis of the Swift-BAT burst
  15. GRB051006: Swift detection of a burst
  16. GRB 050906, summary of radio observations
  17. GRB051001: Swift UVOT Upper Limits
  18. GRB 050925: Second Epoch WSRT Radio Observations
  19. GRB 051001: I-band limit
  20. GRB 051001: AAT infra-red observations
  21. GRB 051001: Swift-BAT refined analysis
  22. GRB 051001: Swift Detection of a Burst
  23. GRB 050820A: NIR photometry at the TNG
  24. GRB050925: Swift/XRT limits
  25. GRB/SGR 050925: IR Observations
  26. GRB 050922C: break in the lightcurve
  27. GRB050925: Swift UVOT upper limits
  28. Refined analysis of the Swift-BAT soft short burst
  29. GRB050925: Faulkes Telescope North R-band limit
  30. GRB050925: Swift-BAT detection of a short burst
  31. GRB050922C: TNG spectroscopic observations
  32. GRB050922B: refined XRT analysis
  33. GRB050922B: Swift UVOT early upper limits.
  34. GRB050922C: Optical Observations
  35. GRB 050922C: Swift XRT refined analysis
  36. HETE Fregate observations of GRB 050922C
  37. GRB 050922C: Swift-BAT refined analysis
  38. GRB 050922B: Swift-BAT refined analysis
  39. GRB 050922C: optical obserations
  40. GRB 050922C: NOT optical observations
  41. GRB 050922C: Swift detection of a bright burst
  42. GRB 050922B: ROTSE-III Optical Limits
  43. GRB 050922B,optical observation
  44. GRB050922B: Swift-BAT detection of a weak long burst
  45. GRB050820B: analysis of the XMM-Newton observation
  46. GRB050916: Swift/UVOT Upper Limits
  47. GRB 050916: Swift-BAT refined analysis
  48. Swift-BAT trigger 155764 is not a GRB
  49. Swift-BAT trigger 155764 is probably not a GRB
  50. Swift trigger 155764: bad XRT centroid
  51. Swift-BAT trigger 155535 is definitely not a GRB
  52. GRB050916 : Swift-XRT refined analysis
  53. GRB 050915B: Swift-BAT refined analysis
  54. GRB 050915B: Swift/UVOT Upper Limits
  55. GRB 050915a: IR Transient
  56. GRB 050915b, SMARTS optical/IR observations
  57. GRB050915B: Swift-BAT detection of a long bright burst
  58. GRB050915: Swift/UVOT upper limits
  59. GRB 050915: IR Observations
  60. GRB 050915: Swift XRT refined analysis
  61. GRB 050915: Swift-BAT refined analysis
  62. GRB 050915: Swift detection of a GRB
  63. GRB050911: Upper limit on X-ray afterglow
  64. Swift-BAT trigger 155072 ground analysis
  65. Swift-BAT trigger 155072 is probably not a GRB
  66. GRB 050908: DEIMOS spectrum and further analysis
  67. GRB 050911, optical content of Swift/XRT error box
  68. GRB 050911: Swift-BAT refined analysis
  69. GRB 050911: z~0.16 cluster in the field
  70. GRB050911: Swift-BAT detection of a long burst
  71. GRB 050910a: TAROT early optical limits
  72. WIRO observations in I of GRB 050908
  73. GRB 050906: Possible X-ray Counterpart
  74. GRB050908: Swift/UVOT Early upper limits
  75. GRB050908 : Swift-XRT refined analysis
  76. GRB 050908: Swift-BAT refined analysis
  77. GRB 050908: Optical observations
  78. GRB 050908: Optical Observations
  79. GRB 050908: Swift detection of a burst
  80. GRB 050906: Optical observations at the Very Large Telescope
  81. GRB 050904 BAT refined analysis of complete data set
  82. GRB 050904: Subaru Optical Spectroscopy
  83. GRB 050906: MARGE Optical Limits
  84. GRB 050906: Swift-BAT refined analysis
  85. GRB 050906: Swift XRT upper limit
  86. GRB 050906: Radio Observations
  87. GRB 050904: Keck I-band Imaging
  88. GRB050906: P60 Observations
  89. GRB 050904: more VLT NIR observations
  90. GRB 050904: photometric redshift
  91. GRB 050904: Swift/UVOT observations
  92. GRB 050904: NIR object inside the XRT error box
  93. GRB 050904: early Swift XRT analysis results
  94. GRB 050904: SOAR YJ and PROMPT Ic Observations
  95. GRB050904: Optical Observations
  96. GRB050904: P60 Observations
  97. GRB 050904: TAROT optical limits
  98. GRB 050827 : OSN 1.5m optical observations
  99. GRB 050827: P200 NIR Observations
  100. GRB050827: Swift/UVOT upper limits

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