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

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