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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"

20882 results found.

  1. GRB 051016: PROMPT Observations
  2. GRB051016: Swift detection of a burst
  3. GRB051006: optical observations
  4. GRB 051012: Swift-BAT detection of burst yesterday
  5. Swift-BAT Trigger 159578 is a possible burst
  6. GRB050805A: Rc optical observations
  7. GRB 051006: Swift/UVOT Upper Limits
  8. GRB051008: optical candidate
  9. GRB 051008 - a low redshift low-luminosity burst?
  10. GRB051008: Swift XRT refined analysis
  11. GRB051008: Radio Observation
  12. GRB 051008, optical observations
  13. GRB 051008: early Swift XRT analysis
  14. GRB 051008: Swift UVOT Candidate
  15. GRB051008: Swift-BAT detection of a bright burst
  16. GRB 051006: P60 Observations
  17. GRB 051006: XRT refined analysis
  18. Swift-BAT trigger 158700 is a probable Cosmic Ray Shower Event
  19. GRB 051006: optical observations at Sierra Nevada
  20. GRB051006: Refined analysis of the Swift-BAT burst
  21. GRB051006: Swift detection of a burst
  22. GRB 050906, summary of radio observations
  23. GRB051001: Swift UVOT Upper Limits
  24. GRB 050925: Second Epoch WSRT Radio Observations
  25. GRB 051001: AAT infra-red observations
  26. GRB 051001: Swift Detection of a Burst
  27. GRB 051001: ROTSE-III Optical Limits
  28. GRB 050820A: NIR photometry at the TNG
  29. GRB050925: Swift/XRT limits
  30. GRB/SGR 050925: IR Observations
  31. GRB 050925: WSRT Radio Observations
  32. GRB050925: Swift UVOT upper limits
  33. GRB 050925 : I-band observation at Xinglong observatory
  34. GRB050925: Faulkes Telescope North R-band limit
  35. GRB050925: Swift-BAT detection of a short burst
  36. GRB050922B: refined XRT analysis
  37. GRB050922B: Swift UVOT early upper limits.
  38. INT 2.5m limit for GRB050922B
  39. GRB 050922B: optical limit
  40. GRB 050922C: Swift-BAT refined analysis
  41. GRB 050922C: optical obserations
  42. GRB 050922C: NOT optical observations
  43. GRB 050922A: Analysis of Swift/XRT TOO observation
  44. GRB 050922C: Swift detection of a bright burst
  45. GRB 050922B: ROTSE-III Optical Limits
  46. GRB 050922B,optical observation
  47. GRB050922B: Swift-BAT detection of a weak long burst
  48. GRB050820B: analysis of the XMM-Newton observation
  49. GRB050916: Swift/UVOT Upper Limits
  50. GRB 050915a: Radio Observations
  51. Swift-BAT trigger 155764 is not a GRB
  52. Swift-BAT trigger 155764 is probably not a GRB
  53. Swift trigger 155764: bad XRT centroid
  54. Swift-BAT trigger 155535 is definitely not a GRB
  55. GRB050916 : Swift-XRT refined analysis
  56. GRB 050915B: Swift/UVOT Upper Limits
  57. GRB050916: Swift-BAT detection of a long weak burst
  58. GRB 050915a: IR Transient
  59. GRB 050915b, SMARTS optical/IR observations
  60. GRB050915B: Swift-BAT detection of a long bright burst
  61. GRB050915: Swift/UVOT upper limits
  62. GRB 050915: KAIT optical limit
  63. GRB 050915: IR Observations
  64. GRB 050915: Swift-BAT refined analysis
  65. GRB050915: P60 Optical Observations
  66. GRB 050915: ROTSE-III optical limits
  67. GRB 050915: Swift detection of a GRB
  68. GRB050911: Upper limit on X-ray afterglow
  69. Swift-BAT trigger 155072 ground analysis
  70. Swift-BAT trigger 155072 is probably not a GRB
  71. GRB 050911: LCO limits on a variable source
  72. GRB 050911, optical content of Swift/XRT error box
  73. GRB050911: Swift-XRT position
  74. GRB 050911: z~0.16 cluster in the field
  75. GRB050911: Swift-BAT detection of a long burst
  76. GRB050908: detection of Swift/UVOT optical counterpart
  77. GRB 050910a: TAROT early optical limits
  78. GRB 050906: Possible X-ray Counterpart
  79. GRB050908: Swift/UVOT Early upper limits
  80. GRB050908 : Swift-XRT refined analysis
  81. GRB 050908: Optical observations
  82. GRB 050908: Swift detection of a burst
  83. GRB 050906: Optical observations at the Very Large Telescope
  84. GRB 050904 BAT refined analysis of complete data set
  85. GRB 050904: Subaru Optical Spectroscopy
  86. GRB 050906: Swift-BAT refined analysis
  87. GRB 050906: Swift XRT upper limit
  88. GRB 050904: Keck I-band Imaging
  89. GRB050906: P60 Observations
  90. GRB 050904: more VLT NIR observations
  91. GRB 050906: Swift/BAT Detection of a possible burst
  92. GRB 050904: photometric redshift
  93. GRB 050904: Swift/UVOT observations
  94. GRB 050904: NIR object inside the XRT error box
  95. GRB050904: Optical Observations
  96. GRB050904: P60 Observations
  97. GRB 050904: TAROT optical limits
  98. GRB050904: Swift-BAT detection of a probable burst
  99. GRB 050827: P200 NIR Observations
  100. GRB050827: Swift/UVOT upper limits

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