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

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