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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. GRB 050714B: candidate afterglow does not fade
  2. GRB050714B: Refined analysis of the Swift-BAT burst
  3. GRB 050714B: optical afterglow
  4. Swift detection of a long transient (GRB 050714B?)
  5. GRB 050709: optical afterglow candidate
  6. GRB 050714, R-band candidate
  7. GRB 050714: Swift XRT afterglow position
  8. GRB 050714, optical observations
  9. GRB 050714A: ROTSE-III Optical Limits
  10. GRB 050714 - A long GRB detected with INTEGRAL
  11. GRB 050713A: XRT refined analysis
  12. GRB 050709: Spectroscopy
  13. GRB 050713A: RAPTOR detection of early optical emission
  14. GRB050713B :Swift/UVOT observations
  15. GRB050713b: XRT refined analysis
  16. GRB050712: TNG R-band observations
  17. GRB 050713B: Swift-BAT Refined Analysis
  18. Swift-BAT Trigger 145729 is not a GRB
  19. GRB 050713A: Swift/UVOT observation
  20. GRB 050713A : Swift-BAT Refined Analysis
  21. GRB050712: Swift UVOT Observation of Afterglow Emission
  22. GRB 050713A : Lulin R-band observation
  23. GRB 050713A XMM-Newton observation
  24. GRB 050713b : Lulin R-band observations
  25. GRB050713B: Faulkes North Telescope observation
  26. RBO RI observations of GRB 050713A
  27. GRB 050713B
  28. GRB050709 : Chandra source optical counterpart
  29. GRB050713: Liverpool Telescope prompt observations
  30. GRB 050712, optical observations
  31. GRB 050713 : Planned XMM-Newton observation
  32. GRB050709: Candidate X-ray Afterglow from Chandra
  33. GRB 050713, R-band observations at NOT
  34. GRB 050713: ARC NIR Detections and Identification of Fading
  35. GRB050713: possible I-band afterglow
  36. GRB 050713: Swift detection of Bright Burst
  37. GRB 050713A: ROTSE-III Optical Limits
  38. GRB050712: XRT refined analysis
  39. GRB050709: Radio Observations
  40. GRB 050709: Swift UVOT and XRT observations
  41. GRB 050712: Swift-BAT Refined Analysis
  42. GRB050712: UVOT candidate optical counterpart
  43. GRB 050712: Swift XRT afterglow position
  44. GRB 050712: Swift detection of a weak burst
  45. GRB 050709: LCO40 Observations
  46. GRB050709, optical observations
  47. GRB050709: A Possible Short-Hard GRB Localized by HETE
  48. PROMPT Rc Observations of GRB 050709
  49. GRB 050525a: PROMPT VRcIc Detections
  50. GRB 050525a: ARC 3.5-meter Optical and NIR Observations
  51. GRB 050525a: ARC 3.5-Meter SPIcam Field Calibration
  52. GRB 050626 optical observations
  53. GRB 050626: Swift XRT observations
  54. GRB 050701
  55. GRB 050701, optical observations
  56. GRB 050408: ARC 3.5-meter NIR Observations
  57. GRB 050701: Refined XRT analysis
  58. Swift UVOT observations of GRB 050701
  59. GRB050701: Swift-BAT Refined analysis
  60. GRB 050701: Swift XRT afterglow position
  61. Swift trigger 143708 is really GRB 050701
  62. GRB 050607, radio observations
  63. H11603: An X-ray flare from V4641 Sgr, or a possible XRF
  64. GRB 050626 - Correction to GCN 3552
  65. GRB 050626 - a long GRB detected with INTEGRAL
  66. GRB 050525A: Swift Late-Time Decay Rate
  67. GRB050525a: HST Observations
  68. CORRECTION: GRB050603 Swift UVOT Afterglow Observations
  69. H3804: A Possible New XRB Detected by HETE
  70. H3800 and H3801 on 2005 June 11: two bursts from SGR1806-20 localized by HETE
  71. XRF 050509c: Optical monitoring
  72. Konus-Wind observation of an intermediate burst from SGR 1806-20
  73. IBAS Alert #2512 is NOT a GRB
  74. XRF050509c: Radio Detection
  75. GRB 050416(a): Host Galaxy Redshift Determination
  76. GRB 050607: MDM Observation
  77. GRB 050607 optical decay
  78. GRB 050607: RTT150 optical observations
  79. GRB050607: refined analysis of prompt REM observations
  80. Swift/UVOT observations of GRB050607
  81. GRB 050607 : Lulin R-band observation
  82. GRB 050607: PROMPT VRcIc Observations
  83. GRB 050607: RAPTOR-S Early Optical Limits
  84. GRB050607: KAIT optical limits
  85. GRB 050525a, Mid-Infrared Observations
  86. GRB 050607: Optical decay and spectral slope
  87. GRB 050607: MDM Observations
  88. GRB050607,optical observation
  89. GRB 050607 - XRT refined data analysis
  90. Optical Afterglow of GRB 050607
  91. GRB050607 optical limit by "Pi of the Sky"
  92. GRB050607: Swift Detection of a long GRB
  93. GRB050607: P60 Observations
  94. GRB050607: prompt REM observations
  95. GRB 050603: prediction of t_break
  96. Limits on a SN in the field of GRB 050509b
  97. GRB 050603: Redshift
  98. GRB 050603 - XRT data analysis of the first day
  99. Konus-Wind observation of GRB 050603
  100. GRB 050603: Analysis of UVOT data

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