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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"

37504 results found.

  1. GRB051006: optical observations
  2. GRB 051012: Swift-BAT detection of burst yesterday
  3. Swift trigger 159578 is not a burst
  4. GRB 051006: Swift/UVOT Upper Limits
  5. IBAS Alert 2675 : not a GRB
  6. GRB051008: optical candidate
  7. GRB 051008: - a high redshift high-luminosity burst?
  8. GRB 051008 - a low redshift low-luminosity burst?
  9. IBAS Alert 2673: not a real GRB
  10. GRB051011: MASTER optical observation
  11. GRB051008: optical observation
  12. GRB051008: Swift XRT refined analysis
  13. GRB051008 - Swift UVOT upper limits
  14. Konus-Wind observation of GRB 051008
  15. GRB051008: Final refined analysis of the Swift-BAT burst
  16. GRB 051008: R-band upper limit
  17. GRB051008: Radio Observation
  18. GRB 051008: Swift XRT position
  19. GRB 051008, optical observations
  20. GRB 051008: early Swift XRT analysis
  21. GRB 051008: Swift UVOT Candidate
  22. GRB 051006: P60 Observations
  23. grb test
  24. GRB 051006: XRT refined analysis
  25. GRB 051006: optical observations at Sierra Nevada
  26. GRB 051006: XRT position
  27. GRB 050906, summary of radio observations
  28. GRB 050925: Second Epoch WSRT Radio Observations
  29. GRB 051001: Swift XRT refined analysis
  30. GRB 051001, optical observations at Mt. John
  31. GRB 051001: I-band limit
  32. GRB 051001: AAT infra-red observations
  33. GRB 051001: Swift-BAT refined analysis
  34. GRB 051001: Swift Detection of a Burst
  35. GRB 051001: ROTSE-III Optical Limits
  36. GRB050908: optical observations
  37. GRB050922C: optical observation
  38. GRB050922B: optical limit
  39. GRB 050922C: further VLT observations
  40. GRB 050820A: NIR photometry at the TNG
  41. GRB050922C: UVES/VLT high resolution spectroscopy
  42. GRB050925: Swift/XRT limits
  43. GRB/SGR 050925: IR Observations
  44. GRB 050922C: break in the lightcurve
  45. GRB 050925: WSRT Radio Observations
  46. GRB 050925 : I-band observation at Xinglong observatory
  47. GRB050925: Faulkes Telescope North R-band limit
  48. GRB050925: Swift-BAT detection of a short burst
  49. GRB 050922B: Correction to BAT refined analysis, longer burst
  50. GRB050922C: TNG spectroscopic observations
  51. GRB050922B: refined XRT analysis
  52. Konus-Wind observation of GRB 050922C
  53. GRB 050922C: Refined redshift
  54. GRB OT observation
  55. GRB050922C: observation at MonteBoo
  56. INT 2.5m limit for GRB050922B
  57. GRB 050922B: optical limit
  58. GRB050922C: Optical Observations
  59. GRB 050922C: Swift XRT refined analysis
  60. HETE Fregate observations of GRB 050922C
  61. GRB 050922C: Swift-BAT refined analysis
  62. GRB 050922B: Swift-BAT refined analysis
  63. GRB 050922C: Absorption redshift from the Nordic Optical Telescope
  64. GRB 050922C: optical obserations
  65. GRB 050922C: NOT optical observations
  66. GRB 050922A: Analysis of Swift/XRT TOO observation
  67. GRB 050922C: Swift detection of a bright burst
  68. GRB 050922C: ROTSE-IIId Refined Analysis
  69. GRB 050922C: ROTSE-III Detection of Possible Counterpart
  70. GRB 050922B: ROTSE-III Optical Limits
  71. GRB 050922B,optical observation
  72. GRB050922B: Swift-BAT detection of a weak long burst
  73. Possible GRB 050922 detected by INTEGRAL
  74. GRB050820B: analysis of the XMM-Newton observation
  75. GRB050916: Swift/UVOT Upper Limits
  76. GRB 050916: Swift-BAT refined analysis
  77. GRB 050918 - A long GRB detected by INTEGRAL
  78. GRB 050915a: Radio Observations
  79. Swift-BAT trigger 155764 is not a GRB
  80. Swift-BAT trigger 155764 is probably not a GRB
  81. Swift-BAT trigger 155535 is definitely not a GRB
  82. GRB 050916: XRT position
  83. GRB 050915b, SMARTS optical/IR observations of the XRT position
  84. GRB 050915B: Swift-BAT refined analysis
  85. GRB 050915B: Swift/UVOT Upper Limits
  86. GRB 050915a: IR Transient
  87. GRB 050915B: XRT position
  88. GRB 050915b, SMARTS optical/IR observations
  89. GRB 050915: KAIT optical limit
  90. GRB 050915: IR Observations
  91. GRB 050915: Swift XRT refined analysis
  92. GRB 050915: Swift-BAT refined analysis
  93. GRB050915: P60 Optical Observations
  94. GRB 050915: ROTSE-III optical limits
  95. GRB 050915: Swift detection of a GRB
  96. GRB050911: Upper limit on X-ray afterglow
  97. Swift-BAT trigger 155072 ground analysis
  98. Swift-BAT trigger 155072 is probably not a GRB
  99. GRB 050911: LCO limits on a variable source
  100. GRB 050908: DEIMOS spectrum and further analysis

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