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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"

26050 results found.

  1. GRB 051006: Swift/UVOT Upper Limits
  2. GRB051008: optical candidate
  3. GRB 051008 - a low redshift low-luminosity burst?
  4. GRB051008: optical observation
  5. GRB051008: Swift XRT refined analysis
  6. GRB051008 - Swift UVOT upper limits
  7. Konus-Wind observation of GRB 051008
  8. GRB051008: Final refined analysis of the Swift-BAT burst
  9. GRB 051008: R-band upper limit
  10. GRB051008: Refined analysis of the Swift-BAT burst
  11. GRB051008: Radio Observation
  12. GRB 051008: Swift XRT position
  13. GRB 051008, optical observations
  14. GRB 051008: early Swift XRT analysis
  15. GRB 051008: Swift UVOT Candidate
  16. GRB051008: Swift-BAT detection of a bright burst
  17. GRB 051006: P60 Observations
  18. GRB 051006: XRT refined analysis
  19. Swift-BAT trigger 158700 is a probable Cosmic Ray Shower Event
  20. GRB 051006: optical observations at Sierra Nevada
  21. GRB051006: Refined analysis of the Swift-BAT burst
  22. GRB 051006: XRT position
  23. GRB051006: Swift detection of a burst
  24. GRB 050906, summary of radio observations
  25. Swift-BAT triggers 158261 and 158262 Retraction
  26. GRB051001: Swift UVOT Upper Limits
  27. GRB 050925: Second Epoch WSRT Radio Observations
  28. GRB 051001: Swift XRT refined analysis
  29. GRB 051001, optical observations at Mt. John
  30. GRB 051001: I-band limit
  31. GRB 051001: AAT infra-red observations
  32. GRB 051001: Swift-BAT refined analysis
  33. GRB 051001: Swift Detection of a Burst
  34. GRB 051001: ROTSE-III Optical Limits
  35. GRB050922B: optical limit
  36. GRB 050922C: further VLT observations
  37. GRB050922C: UVES/VLT high resolution spectroscopy
  38. GRB050925: Swift/XRT limits
  39. GRB/SGR 050925: IR Observations
  40. GRB050922C - Swift UVOT preliminary analysis
  41. GRB 050922C: break in the lightcurve
  42. GRB 050925: WSRT Radio Observations
  43. GRB050925: Swift UVOT upper limits
  44. Refined analysis of the Swift-BAT soft short burst
  45. GRB050925: Faulkes Telescope North R-band limit
  46. GRB050925: Swift-BAT detection of a short burst
  47. GRB 050922B: Correction to BAT refined analysis, longer burst
  48. GRB050922C: TNG spectroscopic observations
  49. GRB050922B: refined XRT analysis
  50. Konus-Wind observation of GRB 050922C
  51. GRB050922B: Swift UVOT early upper limits.
  52. INT 2.5m limit for GRB050922B
  53. GRB 050922B: optical limit
  54. GRB 050922C: Swift XRT refined analysis
  55. HETE Fregate observations of GRB 050922C
  56. GRB 050922C: Swift-BAT refined analysis
  57. GRB 050922B: Swift-BAT refined analysis
  58. GRB050922C: optical observations
  59. GRB 050922C: Absorption redshift from the Nordic Optical Telescope
  60. GRB 050922C: optical obserations
  61. GRB 050922C: NOT optical observations
  62. GRB 050922A: Analysis of Swift/XRT TOO observation
  63. GRB 050922C: Swift detection of a bright burst
  64. GRB 050922C: ROTSE-IIId Refined Analysis
  65. GRB 050922C: ROTSE-III Detection of Possible Counterpart
  66. GRB 050922B: ROTSE-III Optical Limits
  67. GRB 050922B,optical observation
  68. GRB050922B: Swift-BAT detection of a weak long burst
  69. GRB050918: Possible Swift/XRT detected afterglow
  70. GRB050820B: analysis of the XMM-Newton observation
  71. GRB050916: Swift/UVOT Upper Limits
  72. GRB 050916: Swift-BAT refined analysis
  73. GRB 050915a: Radio Observations
  74. Swift-BAT trigger 155764 is not a GRB
  75. Swift-BAT trigger 155764 is probably not a GRB
  76. Swift trigger 155764: bad XRT centroid
  77. Swift-BAT trigger 155535 is definitely not a GRB
  78. GRB050916 : Swift-XRT refined analysis
  79. GRB 050916: XRT position
  80. GRB 050915b, SMARTS optical/IR observations of the XRT position
  81. GRB 050915B: Swift-BAT refined analysis
  82. GRB 050915B: Swift/UVOT Upper Limits
  83. GRB050916: Swift-BAT detection of a long weak burst
  84. GRB 050915a: IR Transient
  85. GRB 050915B: XRT position
  86. GRB050915B: Swift-BAT detection of a long bright burst
  87. GRB050915: Swift/UVOT upper limits
  88. GRB 050915: KAIT optical limit
  89. GRB 050915: IR Observations
  90. GRB 050915: Swift XRT refined analysis
  91. GRB 050915: Swift-BAT refined analysis
  92. GRB050915: P60 Optical Observations
  93. GRB050915, optical observations
  94. GRB050915: XRT position
  95. GRB 050915: ROTSE-III optical limits
  96. GRB 050915: Swift detection of a GRB
  97. GRB050911: Upper limit on X-ray afterglow
  98. Swift-BAT trigger 155072 ground analysis
  99. Swift-BAT trigger 155072 is probably not a GRB
  100. GRB050914: XRT position probably due to cosmic ray

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