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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"

25841 results found.

  1. GRB 050802: Swift-BAT refined analysis
  2. GRB050801: Optical photometry and decay index
  3. GRB 050802: Swift Gamma-ray Burst
  4. GCN 050801: early Swift XRT analysis results
  5. GRB 050730: XRT refined analysis
  6. GRB 050730: early TAROT optical observations
  7. GRB 050730, spectra and optical photometry
  8. GRB050730: Refined BAT analysis of the Swift-BAT burst
  9. GRB 050730: Swift XRT afterglow observations
  10. GRB 050730 XMM-Newton observation
  11. GRB050730: Liverpool Telescope optical observations
  12. GRB 050730, optical candidate
  13. GRB050730: Swift-BAT detection of a weak burst
  14. GRB 050713A: Swift XRT extended light curve
  15. GRB 050724: WHT optical observations
  16. GRB050713: analysis of the XMM-Newton observation
  17. Swift-BAT trigger 147918 is not a real GRB
  18. GRB050709: Second Epoch Chandra Observation
  19. GRB 050724: dust-scattered X-ray halo detected in SWIFT/XRT observation
  20. GRB 050726: early Swift XRT analysis results
  21. GRB 050724: Optical Variability in Nearby Galaxy
  22. GRB 050724: J-band observations
  23. GRB 050724: GMOS Imaging and Spectroscopy
  24. RXTE ASM Detection of GRB050724
  25. GRB050724: Radio Observation
  26. GRB 050724: Optical imaging/astrometry
  27. GRB 050724: RTT150 optical observations
  28. GRB 050724: Swift/UVOT Upper Limit
  29. GRB 050724: early Swift XRT analysis results
  30. GRB050724: Refined analysis of the Swift-BAT possible short burst
  31. GRB 050724: possible host galaxy in DSS
  32. GRB 050721A: Swift-BAT refined analysis
  33. GRB 050721A: Early Swift XRT analysis results
  34. GRB050721A: optical decay
  35. GRB 050721: optical afterglow confirmed
  36. GRB 050709: Refined Spectral and Temporal Properties
  37. GRB050714b: Radio Observation
  38. GRB050712: Radio Observations
  39. GRB050713a: Radio Observation
  40. Swift-BAT trigger 146731 is not a real GRB
  41. GRB 050712, Tautenburg optical afterglow observations
  42. Swift-BAT detection of a possible GRB
  43. GRB 050714B: VLT R-band observations
  44. GRB 050717: Additional LCO observations
  45. GRB 050716; J-band observations
  46. GRB 050717: LCO near-IR observations
  47. Swift/UVOT Observations of GRB 050717
  48. GRB 050717: Swift-BAT refined analysis
  49. GRB 050717: Refined XRT analysis.
  50. GRB050717: Swift XRT position
  51. Swift detection of GRB 050717
  52. Swift UVOT Observations of GRB 050716
  53. GRB 050716: Refined XRT analysis.
  54. GRB050716: Refined analysis of the Swift-BAT burst
  55. GRB 050716: Lulin B and R band optical observations
  56. GRB050716, optical observation
  57. GRB050716: Faulkes North Telescope observation
  58. GRB050715: Refined analysis of the Swift-BAT burst
  59. GRB 050715: Swift-BAT detection
  60. GRB 050714B: refined XRT analysis
  61. GRB 050713b: RTT150 optical observations
  62. GRB050714B: Refined analysis of the Swift-BAT burst
  63. GRB 050714B: optical afterglow
  64. GRB 050714, R-band candidate
  65. GRB 050714, optical observations
  66. GRB 050713A: XRT refined analysis
  67. GRB 050713A: RAPTOR detection of early optical emission
  68. GRB050713B :Swift/UVOT observations
  69. GRB050713b: XRT refined analysis
  70. GRB050712: TNG R-band observations
  71. GRB 050713B: Swift-BAT Refined Analysis
  72. GRB 050713A: Swift/UVOT observation
  73. GRB 050713A : Swift-BAT Refined Analysis
  74. GRB050712: Swift UVOT Observation of Afterglow Emission
  75. GRB 050713A XMM-Newton observation
  76. GRB050713B: Faulkes North Telescope observation
  77. GRB 050713B
  78. GRB050709 : Chandra source optical counterpart
  79. GRB050713: Liverpool Telescope prompt observations
  80. GRB 050712, optical observations
  81. GRB050709: Candidate X-ray Afterglow from Chandra
  82. GRB 050713, R-band observations at NOT
  83. GRB050713: possible I-band afterglow
  84. GRB050709: Radio Observations
  85. GRB 050709: Swift UVOT and XRT observations
  86. GRB 050712: Swift-BAT Refined Analysis
  87. GRB050712: UVOT candidate optical counterpart
  88. GRB 050709: LCO40 Observations
  89. GRB050709, optical observations
  90. GRB050709: A Possible Short-Hard GRB Localized by HETE
  91. PROMPT Rc Observations of GRB 050709
  92. GRB 050525a: PROMPT VRcIc Detections
  93. GRB 050525a: ARC 3.5-meter Optical and NIR Observations
  94. GRB 050525a: ARC 3.5-Meter SPIcam Field Calibration
  95. GRB 050626: Swift XRT observations
  96. GRB 050701
  97. GRB 050701, optical observations
  98. GRB 050408: ARC 3.5-meter NIR Observations
  99. GRB 050701: Refined XRT analysis
  100. Swift UVOT observations of GRB 050701

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