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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 051022, refined optical astrometry
  2. Chandra Observations of GRB 051022
  3. GRB051012: Swift-XRT analysis
  4. GRB 051022 Chandra Observations scheduled
  5. GRB051021B: Swift XRT refined analysis
  6. GRB051021a: optical observations
  7. GRB 051022: WSRT Radio Detection
  8. GRB 051022, mm counterpart
  9. GRB051022: host galaxy redshift
  10. GRB 051022: Swift/UVOT Upper Limits
  11. GRB051022: Radio Counterpart
  12. GRB051022: IR observations
  13. GRB 051022: SOAR JKs Observations
  14. GRB051021A: Swift XRT refined analysis
  15. Konus-Wind observation of GRB 051022
  16. GRB051022: Optical Observations
  17. GRB 051022: Magellan NIR imaging
  18. GRB 051021: PROMPT RcIc Observations
  19. GRB051021b: Magellan IR Imaging
  20. GRB 051022: Spectral Analysis Indicates That The Spectrum Is Absorbed
  21. GRB 051021: Correction
  22. GRB 051022, J & K-band observation
  23. GRB 051021, SMARTS optical/IR observations
  24. GRB051022: Swift XRT Position
  25. GRB 051021: P200 Ks Observations
  26. IPN triangulation of GRB051022 (=H3950)
  27. GRB 051021: MDM Upper Limit
  28. GRB 051022 (=H3950): SXC Flight Localization is Valid
  29. GRB051021: Swift/UVOT Upper Limits
  30. GRB 051021B: Refined analysis of the Swift-BAT burst
  31. GRB 051022: SSO40 Optical Observations
  32. GRB051022,optical observation
  33. GRB 051022A: ROTSE-III Optical Limits
  34. GRB051022 (=H3590), A GRB Detected By HETE
  35. GRB 051022: Optical observations
  36. GRB 051021,optical observation
  37. GRB051021B: Swift XRT Position
  38. GRB 051021: SOAR NIR Observations
  39. GRB 051021B: Swift detection of a burst
  40. GRB051021: Swift XRT analysis
  41. GRB051021 (=H3947): Refined Analysis
  42. GRB 051021 : optical afterglow observation at Lulin
  43. GRB 051021: Optical observations
  44. GRB 051021: ROTSE-III Confirmation of Optical Counterpart
  45. GRB 051021: Optical observations and candidate afterglow
  46. GRB051021.63
  47. GRB051021.6: MASTER optical observation
  48. Swift-BAT trigger 160640 is not a real GRB
  49. GRB051021: A GRB Localized by HETE
  50. Swift-BAT trigger 160619 is not a GRB
  51. Swift-BAT triggered on a posible CR Shower or possible GRB
  52. GRB 050502b: Optical limit
  53. GRB 051016b: Optical limit
  54. Afterglow candidate of GRB 051016B observed at Lulin
  55. GRB 051016b: Gemini Near IR Observations
  56. GRB 051016A: Swift/UVOT upper limits
  57. GRB 051016B: refined analysis of the Swift/XRT data
  58. GRB 051016B: Swift/UVOT detection
  59. GRB 051016B,optical observation
  60. GRB 051016B : Optical follow-up at Lulin
  61. GRB 051016B: Refined analysis of the Swift-BAT burst
  62. GRB 051016B: Swift detection of a soft burst
  63. GRB 051016: Swift-BAT refined analysis
  64. GRB051016 XMM-Newton observation
  65. GRB051016: Swift XRT refined analysis.
  66. GRB051016: Planned XMM-Newton observation
  67. GRB 051016: LCO optical and near-IR imaging
  68. GRB 051016: PROMPT Observations
  69. GRB051016: Swift detection of a burst
  70. Photometric calibration of Swift/UVOT and Re-analysis of Swift/UVOT GRB 050922C data
  71. GRB051006: optical observations
  72. GRB 051012: Swift-BAT detection of burst yesterday
  73. Swift trigger 159578 is not a burst
  74. Swift-BAT Trigger 159578 is a possible burst
  75. GRB050805A: Rc optical observations
  76. GRB 051006: Swift/UVOT Upper Limits
  77. IBAS Alert 2675 : not a GRB
  78. GRB051008: optical candidate
  79. GRB 051008: - a high redshift high-luminosity burst?
  80. GRB 051008 - a low redshift low-luminosity burst?
  81. IBAS Alert 2673: not a real GRB
  82. GRB051011: bright nebulae near error box
  83. GRB051011: MASTER optical observation
  84. GRB051008: optical observation
  85. GRB051008: Swift XRT refined analysis
  86. GRB051008 - Swift UVOT upper limits
  87. Konus-Wind observation of GRB 051008
  88. GRB051008: Final refined analysis of the Swift-BAT burst
  89. GRB 051008: R-band upper limit
  90. GRB051008: Refined analysis of the Swift-BAT burst
  91. GRB051008: Radio Observation
  92. GRB 051008: Swift XRT position
  93. GRB 051008, optical observations
  94. GRB 051008: early Swift XRT analysis
  95. GRB 051008: Swift UVOT Candidate
  96. GRB051008: Swift-BAT detection of a bright burst
  97. GRB 051006: P60 Observations
  98. grb test
  99. GRB 051006: XRT refined analysis
  100. Swift-BAT trigger 158700 is a probable Cosmic Ray Shower Event

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