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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"
  1. GRB051022 (=H3590), A GRB Detected By HETE
  2. GRB 051022: Optical observations
  3. GRB 051021,optical observation
  4. GRB051021B: Swift XRT Position
  5. GRB 051021: SOAR NIR Observations
  6. GRB 051021B: Swift detection of a burst
  7. GRB051021: Swift XRT analysis
  8. GRB051021 (=H3947): Refined Analysis
  9. GRB 051021 : optical afterglow observation at Lulin
  10. GRB 051021: Optical observations
  11. GRB 051021: ROTSE-III Confirmation of Optical Counterpart
  12. GRB 051021: Optical observations and candidate afterglow
  13. GRB051021.63
  14. GRB051021.6: MASTER optical observation
  15. Swift-BAT trigger 160640 is not a real GRB
  16. GRB051021: A GRB Localized by HETE
  17. Swift-BAT trigger 160619 is not a GRB
  18. Swift-BAT triggered on a posible CR Shower or possible GRB
  19. GRB 050502b: Optical limit
  20. GRB 051016b: Optical limit
  21. Afterglow candidate of GRB 051016B observed at Lulin
  22. GRB 051016b: Gemini Near IR Observations
  23. GRB 051016A: Swift/UVOT upper limits
  24. GRB 051016B: refined analysis of the Swift/XRT data
  25. GRB 051016B: Swift/UVOT detection
  26. GRB 051016B,optical observation
  27. GRB 051016B : Optical follow-up at Lulin
  28. GRB 051016B: Refined analysis of the Swift-BAT burst
  29. GRB 051016B: Swift detection of a soft burst
  30. GRB 051016: Swift-BAT refined analysis
  31. GRB051016 XMM-Newton observation
  32. GRB051016: Swift XRT refined analysis.
  33. GRB051016: Planned XMM-Newton observation
  34. GRB 051016: LCO optical and near-IR imaging
  35. GRB 051016: PROMPT Observations
  36. GRB051016: Swift detection of a burst
  37. Photometric calibration of Swift/UVOT and Re-analysis of Swift/UVOT GRB 050922C data
  38. GRB051006: optical observations
  39. GRB 051012: Swift-BAT detection of burst yesterday
  40. Swift trigger 159578 is not a burst
  41. Swift-BAT Trigger 159578 is a possible burst
  42. GRB050805A: Rc optical observations
  43. GRB 051006: Swift/UVOT Upper Limits
  44. IBAS Alert 2675 : not a GRB
  45. GRB051008: optical candidate
  46. GRB 051008: - a high redshift high-luminosity burst?
  47. GRB 051008 - a low redshift low-luminosity burst?
  48. IBAS Alert 2673: not a real GRB
  49. GRB051011: bright nebulae near error box
  50. GRB051011: MASTER optical observation
  51. GRB051008: optical observation
  52. GRB051008: Swift XRT refined analysis
  53. GRB051008 - Swift UVOT upper limits
  54. Konus-Wind observation of GRB 051008
  55. GRB051008: Final refined analysis of the Swift-BAT burst
  56. GRB 051008: R-band upper limit
  57. GRB051008: Refined analysis of the Swift-BAT burst
  58. GRB051008: Radio Observation
  59. GRB 051008: Swift XRT position
  60. GRB 051008, optical observations
  61. GRB 051008: early Swift XRT analysis
  62. GRB 051008: Swift UVOT Candidate
  63. GRB051008: Swift-BAT detection of a bright burst
  64. GRB 051006: P60 Observations
  65. grb test
  66. GRB 051006: XRT refined analysis
  67. Swift-BAT trigger 158700 is a probable Cosmic Ray Shower Event
  68. GRB 051006: optical observations at Sierra Nevada
  69. GRB051006: Refined analysis of the Swift-BAT burst
  70. GRB 051006: XRT position
  71. GRB051006: Swift detection of a burst
  72. GRB 050906, summary of radio observations
  73. Swift-BAT triggers 158261 and 158262 Retraction
  74. GRB051001: Swift UVOT Upper Limits
  75. GRB 050925: Second Epoch WSRT Radio Observations
  76. GRB 051001: Swift XRT refined analysis
  77. GRB 051001, optical observations at Mt. John
  78. GRB 051001: I-band limit
  79. GRB 051001: AAT infra-red observations
  80. GRB 051001: Swift-BAT refined analysis
  81. GRB 051001: Swift Detection of a Burst
  82. GRB 051001: ROTSE-III Optical Limits
  83. GRB050908: optical observations
  84. GRB050922C: optical observation
  85. GRB050922B: optical limit
  86. GRB 050922C: further VLT observations
  87. GRB 050820A: NIR photometry at the TNG
  88. GRB050922C: UVES/VLT high resolution spectroscopy
  89. GRB050925: Swift/XRT limits
  90. GRB/SGR 050925: IR Observations
  91. GRB050922C - Swift UVOT preliminary analysis
  92. GRB 050922C: break in the lightcurve
  93. GRB 050925: WSRT Radio Observations
  94. GRB050925: Swift UVOT upper limits
  95. Refined analysis of the Swift-BAT soft short burst
  96. GRB 050925 : I-band observation at Xinglong observatory
  97. GRB050925: Faulkes Telescope North R-band limit
  98. GRB050925: Swift-BAT detection of a short burst
  99. GRB 050922B: Correction to BAT refined analysis, longer burst
  100. GRB050922C: TNG spectroscopic observations

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