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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. GRB050717: Swift XRT position
  2. Swift detection of GRB 050717
  3. GRB 050716 - UKIRT identification of candidate afterglow
  4. Swift UVOT Observations of GRB 050716
  5. GRB 050716: Refined XRT analysis.
  6. GRB050716: Refined analysis of the Swift-BAT burst
  7. GRB 050716: Lulin B and R band optical observations
  8. GRB050716, optical observation
  9. GRB 050716: Optical Observations
  10. GRB050716: Faulkes North Telescope observation
  11. GRB050716: Correction to sign in XRT coordinate
  12. Swift/BAT detection of GRB 050716
  13. GRB050715: Refined analysis of the Swift-BAT burst
  14. GRB 050715: Swift-BAT detection
  15. Swift UVOT Observations of GRB 050714B
  16. Konus-Wind observation of GRB 050713A
  17. GRB 050714B: refined XRT analysis
  18. GRB 050713b: RTT150 optical observations
  19. GRB 050714B: candidate afterglow does not fade
  20. GRB050714B: Refined analysis of the Swift-BAT burst
  21. GRB 050714B: optical afterglow
  22. Swift detection of a long transient (GRB 050714B?)
  23. GRB 050709: optical afterglow candidate
  24. GRB 050714, R-band candidate
  25. GRB 050714: Swift XRT afterglow position
  26. GRB 050714, optical observations
  27. GRB 050714A: ROTSE-III Optical Limits
  28. GRB 050714 - A long GRB detected with INTEGRAL
  29. GRB 050713A: XRT refined analysis
  30. GRB 050709: Spectroscopy
  31. GRB 050713A: RAPTOR detection of early optical emission
  32. GRB050713B :Swift/UVOT observations
  33. GRB050713b: XRT refined analysis
  34. GRB050712: TNG R-band observations
  35. GRB 050713B: Swift-BAT Refined Analysis
  36. Swift-BAT Trigger 145729 is not a GRB
  37. GRB 050713A: Swift/UVOT observation
  38. GRB 050713A : Swift-BAT Refined Analysis
  39. GRB050712: Swift UVOT Observation of Afterglow Emission
  40. GRB 050713A : Lulin R-band observation
  41. GRB 050713A XMM-Newton observation
  42. GRB 050713b : Lulin R-band observations
  43. GRB050713B: Faulkes North Telescope observation
  44. RBO RI observations of GRB 050713A
  45. GRB 050713B
  46. GRB050709 : Chandra source optical counterpart
  47. GRB050713: Liverpool Telescope prompt observations
  48. GRB 050712, optical observations
  49. GRB 050713 : Planned XMM-Newton observation
  50. GRB050709: Candidate X-ray Afterglow from Chandra
  51. GRB 050713, R-band observations at NOT
  52. GRB 050713: ARC NIR Detections and Identification of Fading
  53. GRB050713: possible I-band afterglow
  54. GRB 050713: Swift detection of Bright Burst
  55. GRB 050713A: ROTSE-III Optical Limits
  56. GRB050712: XRT refined analysis
  57. GRB050709: Radio Observations
  58. GRB 050709: Swift UVOT and XRT observations
  59. GRB 050712: Swift-BAT Refined Analysis
  60. GRB050712: UVOT candidate optical counterpart
  61. GRB 050712: Swift XRT afterglow position
  62. GRB 050712: Swift detection of a weak burst
  63. GRB 050709: LCO40 Observations
  64. GRB050709, optical observations
  65. GRB050709: A Possible Short-Hard GRB Localized by HETE
  66. PROMPT Rc Observations of GRB 050709
  67. GRB 050525a: PROMPT VRcIc Detections
  68. GRB 050525a: ARC 3.5-meter Optical and NIR Observations
  69. GRB 050525a: ARC 3.5-Meter SPIcam Field Calibration
  70. GRB 050626 optical observations
  71. GRB 050626: Swift XRT observations
  72. GRB 050701
  73. GRB 050701, optical observations
  74. GRB 050408: ARC 3.5-meter NIR Observations
  75. GRB 050701: Refined XRT analysis
  76. Swift UVOT observations of GRB 050701
  77. GRB050701: Swift-BAT Refined analysis
  78. GRB 050701: Swift XRT afterglow position
  79. Swift trigger 143708 is really GRB 050701
  80. GRB 050607, radio observations
  81. H11603: An X-ray flare from V4641 Sgr, or a possible XRF
  82. GRB 050626 - Correction to GCN 3552
  83. GRB 050626 - a long GRB detected with INTEGRAL
  84. GRB 050525A: Swift Late-Time Decay Rate
  85. GRB050525a: HST Observations
  86. CORRECTION: GRB050603 Swift UVOT Afterglow Observations
  87. H3804: A Possible New XRB Detected by HETE
  88. H3800 and H3801 on 2005 June 11: two bursts from SGR1806-20 localized by HETE
  89. XRF 050509c: Optical monitoring
  90. Konus-Wind observation of an intermediate burst from SGR 1806-20
  91. IBAS Alert #2512 is NOT a GRB
  92. XRF050509c: Radio Detection
  93. GRB 050416(a): Host Galaxy Redshift Determination
  94. GRB 050607: MDM Observation
  95. GRB 050607 optical decay
  96. GRB 050607: RTT150 optical observations
  97. GRB050607: refined analysis of prompt REM observations
  98. Swift/UVOT observations of GRB050607
  99. GRB 050607 : Lulin R-band observation
  100. GRB 050607: PROMPT VRcIc Observations

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