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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. GRB 051022, mm counterpart
  2. GRB051022: host galaxy redshift
  3. GRB 051022: Swift/UVOT Upper Limits
  4. GRB051022: Radio Counterpart
  5. GRB051022: IR observations
  6. GRB 051022: SOAR JKs Observations
  7. GRB051021A: Swift XRT refined analysis
  8. Konus-Wind observation of GRB 051022
  9. GRB051022: Optical Observations
  10. GRB 051022: Magellan NIR imaging
  11. GRB 051021: PROMPT RcIc Observations
  12. GRB051021b: Magellan IR Imaging
  13. GRB 051022: Spectral Analysis Indicates That The Spectrum Is Absorbed
  14. GRB 051021: Correction
  15. GRB 051022, J & K-band observation
  16. GRB 051021, SMARTS optical/IR observations
  17. GRB051022: Swift XRT Position
  18. GRB 051021: P200 Ks Observations
  19. IPN triangulation of GRB051022 (=H3950)
  20. GRB 051021: MDM Upper Limit
  21. GRB 051022 (=H3950): SXC Flight Localization is Valid
  22. GRB051021: Swift/UVOT Upper Limits
  23. GRB 051021B: Refined analysis of the Swift-BAT burst
  24. GRB 051022: SSO40 Optical Observations
  25. GRB051022,optical observation
  26. GRB 051022A: ROTSE-III Optical Limits
  27. GRB051022 (=H3590), A GRB Detected By HETE
  28. GRB 051022: Optical observations
  29. GRB 051021,optical observation
  30. GRB051021B: Swift XRT Position
  31. GRB 051021: SOAR NIR Observations
  32. GRB 051021B: Swift detection of a burst
  33. GRB051021: Swift XRT analysis
  34. GRB051021 (=H3947): Refined Analysis
  35. GRB 051021 : optical afterglow observation at Lulin
  36. GRB 051021: Optical observations
  37. GRB 051021: ROTSE-III Confirmation of Optical Counterpart
  38. GRB 051021: Optical observations and candidate afterglow
  39. GRB051021.63
  40. GRB051021.6: MASTER optical observation
  41. Swift-BAT trigger 160640 is not a real GRB
  42. GRB051021: A GRB Localized by HETE
  43. Swift-BAT trigger 160619 is not a GRB
  44. Swift-BAT triggered on a posible CR Shower or possible GRB
  45. GRB 050502b: Optical limit
  46. GRB 051016b: Optical limit
  47. Afterglow candidate of GRB 051016B observed at Lulin
  48. GRB 051016b: Gemini Near IR Observations
  49. GRB 051016A: Swift/UVOT upper limits
  50. GRB 051016B: refined analysis of the Swift/XRT data
  51. GRB 051016B: Swift/UVOT detection
  52. GRB 051016B,optical observation
  53. GRB 051016B : Optical follow-up at Lulin
  54. GRB 051016B: Refined analysis of the Swift-BAT burst
  55. GRB 051016B: Swift detection of a soft burst
  56. GRB 051016: Swift-BAT refined analysis
  57. GRB051016 XMM-Newton observation
  58. GRB051016: Swift XRT refined analysis.
  59. GRB051016: Planned XMM-Newton observation
  60. GRB 051016: LCO optical and near-IR imaging
  61. GRB 051016: PROMPT Observations
  62. GRB051016: Swift detection of a burst
  63. Photometric calibration of Swift/UVOT and Re-analysis of Swift/UVOT GRB 050922C data
  64. GRB051006: optical observations
  65. GRB 051012: Swift-BAT detection of burst yesterday
  66. Swift trigger 159578 is not a burst
  67. Swift-BAT Trigger 159578 is a possible burst
  68. GRB050805A: Rc optical observations
  69. GRB 051006: Swift/UVOT Upper Limits
  70. IBAS Alert 2675 : not a GRB
  71. GRB051008: optical candidate
  72. GRB 051008: - a high redshift high-luminosity burst?
  73. GRB 051008 - a low redshift low-luminosity burst?
  74. IBAS Alert 2673: not a real GRB
  75. GRB051011: bright nebulae near error box
  76. GRB051011: MASTER optical observation
  77. GRB051008: optical observation
  78. GRB051008: Swift XRT refined analysis
  79. GRB051008 - Swift UVOT upper limits
  80. Konus-Wind observation of GRB 051008
  81. GRB051008: Final refined analysis of the Swift-BAT burst
  82. GRB 051008: R-band upper limit
  83. GRB051008: Refined analysis of the Swift-BAT burst
  84. GRB051008: Radio Observation
  85. GRB 051008: Swift XRT position
  86. GRB 051008, optical observations
  87. GRB 051008: early Swift XRT analysis
  88. GRB 051008: Swift UVOT Candidate
  89. GRB051008: Swift-BAT detection of a bright burst
  90. GRB 051006: P60 Observations
  91. grb test
  92. GRB 051006: XRT refined analysis
  93. Swift-BAT trigger 158700 is a probable Cosmic Ray Shower Event
  94. GRB 051006: optical observations at Sierra Nevada
  95. GRB051006: Refined analysis of the Swift-BAT burst
  96. GRB 051006: XRT position
  97. GRB051006: Swift detection of a burst
  98. GRB 050906, summary of radio observations
  99. Swift-BAT triggers 158261 and 158262 Retraction
  100. GRB051001: Swift UVOT Upper Limits

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