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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. GRB 051021B: Refined analysis of the Swift-BAT burst
  2. GRB 051022: SSO40 Optical Observations
  3. GRB051022,optical observation
  4. GRB 051022A: ROTSE-III Optical Limits
  5. GRB051022 (=H3590), A GRB Detected By HETE
  6. GRB 051022: Optical observations
  7. GRB 051021,optical observation
  8. GRB051021B: Swift XRT Position
  9. GRB 051021: SOAR NIR Observations
  10. GRB 051021B: Swift detection of a burst
  11. GRB051021: Swift XRT analysis
  12. GRB051021 (=H3947): Refined Analysis
  13. GRB 051021 : optical afterglow observation at Lulin
  14. GRB 051021: Optical observations
  15. GRB 051021: ROTSE-III Confirmation of Optical Counterpart
  16. GRB 051021: Optical observations and candidate afterglow
  17. GRB051021.63
  18. GRB051021.6: MASTER optical observation
  19. Swift-BAT trigger 160640 is not a real GRB
  20. GRB051021: A GRB Localized by HETE
  21. Swift-BAT trigger 160619 is not a GRB
  22. Swift-BAT triggered on a posible CR Shower or possible GRB
  23. GRB 050502b: Optical limit
  24. GRB 051016b: Optical limit
  25. Afterglow candidate of GRB 051016B observed at Lulin
  26. GRB 051016b: Gemini Near IR Observations
  27. GRB 051016A: Swift/UVOT upper limits
  28. GRB 051016B: refined analysis of the Swift/XRT data
  29. GRB 051016B: Swift/UVOT detection
  30. GRB 051016B,optical observation
  31. GRB 051016B : Optical follow-up at Lulin
  32. GRB 051016B: Refined analysis of the Swift-BAT burst
  33. GRB 051016B: Swift detection of a soft burst
  34. GRB 051016: Swift-BAT refined analysis
  35. GRB051016 XMM-Newton observation
  36. GRB051016: Swift XRT refined analysis.
  37. GRB051016: Planned XMM-Newton observation
  38. GRB 051016: LCO optical and near-IR imaging
  39. GRB 051016: PROMPT Observations
  40. GRB051016: Swift detection of a burst
  41. Photometric calibration of Swift/UVOT and Re-analysis of Swift/UVOT GRB 050922C data
  42. GRB051006: optical observations
  43. GRB 051012: Swift-BAT detection of burst yesterday
  44. Swift trigger 159578 is not a burst
  45. Swift-BAT Trigger 159578 is a possible burst
  46. GRB050805A: Rc optical observations
  47. GRB 051006: Swift/UVOT Upper Limits
  48. IBAS Alert 2675 : not a GRB
  49. GRB051008: optical candidate
  50. GRB 051008: - a high redshift high-luminosity burst?
  51. GRB 051008 - a low redshift low-luminosity burst?
  52. IBAS Alert 2673: not a real GRB
  53. GRB051011: bright nebulae near error box
  54. GRB051011: MASTER optical observation
  55. GRB051008: optical observation
  56. GRB051008: Swift XRT refined analysis
  57. GRB051008 - Swift UVOT upper limits
  58. Konus-Wind observation of GRB 051008
  59. GRB051008: Final refined analysis of the Swift-BAT burst
  60. GRB 051008: R-band upper limit
  61. GRB051008: Refined analysis of the Swift-BAT burst
  62. GRB051008: Radio Observation
  63. GRB 051008: Swift XRT position
  64. GRB 051008, optical observations
  65. GRB 051008: early Swift XRT analysis
  66. GRB 051008: Swift UVOT Candidate
  67. GRB051008: Swift-BAT detection of a bright burst
  68. GRB 051006: P60 Observations
  69. grb test
  70. GRB 051006: XRT refined analysis
  71. Swift-BAT trigger 158700 is a probable Cosmic Ray Shower Event
  72. GRB 051006: optical observations at Sierra Nevada
  73. GRB051006: Refined analysis of the Swift-BAT burst
  74. GRB 051006: XRT position
  75. GRB051006: Swift detection of a burst
  76. GRB 050906, summary of radio observations
  77. Swift-BAT triggers 158261 and 158262 Retraction
  78. GRB051001: Swift UVOT Upper Limits
  79. GRB 050925: Second Epoch WSRT Radio Observations
  80. GRB 051001: Swift XRT refined analysis
  81. GRB 051001, optical observations at Mt. John
  82. GRB 051001: I-band limit
  83. GRB 051001: AAT infra-red observations
  84. GRB 051001: Swift-BAT refined analysis
  85. GRB 051001: Swift Detection of a Burst
  86. GRB 051001: ROTSE-III Optical Limits
  87. GRB050908: optical observations
  88. GRB050922C: optical observation
  89. GRB050922B: optical limit
  90. GRB 050922C: further VLT observations
  91. GRB 050820A: NIR photometry at the TNG
  92. GRB050922C: UVES/VLT high resolution spectroscopy
  93. GRB050925: Swift/XRT limits
  94. GRB/SGR 050925: IR Observations
  95. GRB050922C - Swift UVOT preliminary analysis
  96. GRB 050922C: break in the lightcurve
  97. GRB 050925: WSRT Radio Observations
  98. GRB050925: Swift UVOT upper limits
  99. Refined analysis of the Swift-BAT soft short burst
  100. GRB 050925 : I-band observation at Xinglong observatory

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