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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. GRB051028:MASTER observations
  2. GRB 051028 (=H3951): A GRB localized by HETE
  3. GRB051028:MASTER optical observations
  4. GRB 051022: XRT Refined Spectral and Temporal Analysis--Correction
  5. GRB051022: Swift XRT measurement of jet break
  6. SGR 1806-20: continued moderate activity seen with INTEGRAL
  7. GRB051021B: Swift/UVOT Upper limits
  8. GRB 051021, Optical Observations
  9. GRB 051022: XRT Refined Spectral and Temporal Analysis
  10. GRB 051022, refined optical astrometry
  11. Chandra Observations of GRB 051022
  12. GRB051012: Swift-XRT analysis
  13. GRB 051022 Chandra Observations scheduled
  14. GRB051021B: Swift XRT refined analysis
  15. GRB051021a: optical observations
  16. GRB 051022: WSRT Radio Detection
  17. GRB 051022, mm counterpart
  18. GRB051022: host galaxy redshift
  19. GRB 051022: Swift/UVOT Upper Limits
  20. GRB051022: Radio Counterpart
  21. GRB051022: IR observations
  22. GRB 051022: SOAR JKs Observations
  23. GRB051021A: Swift XRT refined analysis
  24. Konus-Wind observation of GRB 051022
  25. GRB051022: Optical Observations
  26. GRB 051022: Magellan NIR imaging
  27. GRB 051021: PROMPT RcIc Observations
  28. GRB051021b: Magellan IR Imaging
  29. GRB 051022: Spectral Analysis Indicates That The Spectrum Is Absorbed
  30. GRB 051021: Correction
  31. GRB 051022, J & K-band observation
  32. GRB 051021, SMARTS optical/IR observations
  33. GRB051022: Swift XRT Position
  34. GRB 051021: P200 Ks Observations
  35. IPN triangulation of GRB051022 (=H3950)
  36. GRB 051021: MDM Upper Limit
  37. GRB 051022 (=H3950): SXC Flight Localization is Valid
  38. GRB051021: Swift/UVOT Upper Limits
  39. GRB 051021B: Refined analysis of the Swift-BAT burst
  40. GRB 051022: SSO40 Optical Observations
  41. GRB051022,optical observation
  42. GRB 051022A: ROTSE-III Optical Limits
  43. GRB051022 (=H3590), A GRB Detected By HETE
  44. GRB 051022: Optical observations
  45. GRB 051021,optical observation
  46. GRB051021B: Swift XRT Position
  47. GRB 051021: SOAR NIR Observations
  48. GRB 051021B: Swift detection of a burst
  49. GRB051021: Swift XRT analysis
  50. GRB051021 (=H3947): Refined Analysis
  51. GRB 051021 : optical afterglow observation at Lulin
  52. GRB 051021: Optical observations
  53. GRB 051021: ROTSE-III Confirmation of Optical Counterpart
  54. GRB 051021: Optical observations and candidate afterglow
  55. GRB051021.63
  56. GRB051021.6: MASTER optical observation
  57. Swift-BAT trigger 160640 is not a real GRB
  58. GRB051021: A GRB Localized by HETE
  59. Swift-BAT trigger 160619 is not a GRB
  60. Swift-BAT triggered on a posible CR Shower or possible GRB
  61. GRB 050502b: Optical limit
  62. GRB 051016b: Optical limit
  63. Afterglow candidate of GRB 051016B observed at Lulin
  64. GRB 051016b: Gemini Near IR Observations
  65. GRB 051016A: Swift/UVOT upper limits
  66. GRB 051016B: refined analysis of the Swift/XRT data
  67. GRB 051016B: Swift/UVOT detection
  68. GRB 051016B,optical observation
  69. GRB 051016B : Optical follow-up at Lulin
  70. GRB 051016B: Refined analysis of the Swift-BAT burst
  71. GRB 051016B: Swift detection of a soft burst
  72. GRB 051016: Swift-BAT refined analysis
  73. GRB051016 XMM-Newton observation
  74. GRB051016: Swift XRT refined analysis.
  75. GRB051016: Planned XMM-Newton observation
  76. GRB 051016: LCO optical and near-IR imaging
  77. GRB 051016: PROMPT Observations
  78. GRB051016: Swift detection of a burst
  79. Photometric calibration of Swift/UVOT and Re-analysis of Swift/UVOT GRB 050922C data
  80. GRB051006: optical observations
  81. GRB 051012: Swift-BAT detection of burst yesterday
  82. Swift trigger 159578 is not a burst
  83. Swift-BAT Trigger 159578 is a possible burst
  84. GRB050805A: Rc optical observations
  85. GRB 051006: Swift/UVOT Upper Limits
  86. IBAS Alert 2675 : not a GRB
  87. GRB051008: optical candidate
  88. GRB 051008: - a high redshift high-luminosity burst?
  89. GRB 051008 - a low redshift low-luminosity burst?
  90. IBAS Alert 2673: not a real GRB
  91. GRB051011: bright nebulae near error box
  92. GRB051011: MASTER optical observation
  93. GRB051008: optical observation
  94. GRB051008: Swift XRT refined analysis
  95. GRB051008 - Swift UVOT upper limits
  96. Konus-Wind observation of GRB 051008
  97. GRB051008: Final refined analysis of the Swift-BAT burst
  98. GRB 051008: R-band upper limit
  99. GRB051008: Refined analysis of the Swift-BAT burst
  100. GRB051008: Radio Observation

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