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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. Swift/BAT detection of GRB 050716
  2. GRB050715: Refined analysis of the Swift-BAT burst
  3. GRB 050715: Swift-BAT detection
  4. Swift UVOT Observations of GRB 050714B
  5. Konus-Wind observation of GRB 050713A
  6. GRB 050714B: refined XRT analysis
  7. GRB 050713b: RTT150 optical observations
  8. GRB 050714B: candidate afterglow does not fade
  9. GRB050714B: Refined analysis of the Swift-BAT burst
  10. GRB 050714B: optical afterglow
  11. Swift detection of a long transient (GRB 050714B?)
  12. GRB 050709: optical afterglow candidate
  13. GRB 050714, R-band candidate
  14. GRB 050714: Swift XRT afterglow position
  15. GRB 050714, optical observations
  16. GRB 050714A: ROTSE-III Optical Limits
  17. GRB 050714 - A long GRB detected with INTEGRAL
  18. GRB 050713A: XRT refined analysis
  19. GRB 050709: Spectroscopy
  20. GRB 050713A: RAPTOR detection of early optical emission
  21. GRB050713B :Swift/UVOT observations
  22. GRB050713b: XRT refined analysis
  23. GRB050712: TNG R-band observations
  24. GRB 050713B: Swift-BAT Refined Analysis
  25. Swift-BAT Trigger 145729 is not a GRB
  26. GRB 050713A: Swift/UVOT observation
  27. GRB 050713A : Swift-BAT Refined Analysis
  28. GRB050712: Swift UVOT Observation of Afterglow Emission
  29. GRB 050713A : Lulin R-band observation
  30. GRB 050713A XMM-Newton observation
  31. GRB 050713b : Lulin R-band observations
  32. GRB050713B: Faulkes North Telescope observation
  33. RBO RI observations of GRB 050713A
  34. GRB 050713B
  35. GRB050709 : Chandra source optical counterpart
  36. GRB050713: Liverpool Telescope prompt observations
  37. GRB 050712, optical observations
  38. GRB 050713 : Planned XMM-Newton observation
  39. GRB050709: Candidate X-ray Afterglow from Chandra
  40. GRB 050713, R-band observations at NOT
  41. GRB 050713: ARC NIR Detections and Identification of Fading
  42. GRB050713: possible I-band afterglow
  43. GRB 050713: Swift detection of Bright Burst
  44. GRB 050713A: ROTSE-III Optical Limits
  45. GRB050712: XRT refined analysis
  46. GRB050709: Radio Observations
  47. GRB 050709: Swift UVOT and XRT observations
  48. GRB 050712: Swift-BAT Refined Analysis
  49. GRB050712: UVOT candidate optical counterpart
  50. GRB 050712: Swift XRT afterglow position
  51. GRB 050712: Swift detection of a weak burst
  52. GRB 050709: LCO40 Observations
  53. GRB050709, optical observations
  54. GRB050709: A Possible Short-Hard GRB Localized by HETE
  55. PROMPT Rc Observations of GRB 050709
  56. GRB 050525a: PROMPT VRcIc Detections
  57. GRB 050525a: ARC 3.5-meter Optical and NIR Observations
  58. GRB 050525a: ARC 3.5-Meter SPIcam Field Calibration
  59. GRB 050626 optical observations
  60. GRB 050626: Swift XRT observations
  61. GRB 050701
  62. GRB 050701, optical observations
  63. GRB 050408: ARC 3.5-meter NIR Observations
  64. GRB 050701: Refined XRT analysis
  65. Swift UVOT observations of GRB 050701
  66. GRB050701: Swift-BAT Refined analysis
  67. GRB 050701: Swift XRT afterglow position
  68. Swift trigger 143708 is really GRB 050701
  69. GRB 050607, radio observations
  70. H11603: An X-ray flare from V4641 Sgr, or a possible XRF
  71. GRB 050626 - Correction to GCN 3552
  72. GRB 050626 - a long GRB detected with INTEGRAL
  73. GRB 050525A: Swift Late-Time Decay Rate
  74. GRB050525a: HST Observations
  75. CORRECTION: GRB050603 Swift UVOT Afterglow Observations
  76. H3804: A Possible New XRB Detected by HETE
  77. H3800 and H3801 on 2005 June 11: two bursts from SGR1806-20 localized by HETE
  78. XRF 050509c: Optical monitoring
  79. Konus-Wind observation of an intermediate burst from SGR 1806-20
  80. IBAS Alert #2512 is NOT a GRB
  81. XRF050509c: Radio Detection
  82. GRB 050416(a): Host Galaxy Redshift Determination
  83. GRB 050607: MDM Observation
  84. GRB 050607 optical decay
  85. GRB 050607: RTT150 optical observations
  86. GRB050607: refined analysis of prompt REM observations
  87. Swift/UVOT observations of GRB050607
  88. GRB 050607 : Lulin R-band observation
  89. GRB 050607: PROMPT VRcIc Observations
  90. GRB 050607: RAPTOR-S Early Optical Limits
  91. GRB050607: KAIT optical limits
  92. GRB 050525a, Mid-Infrared Observations
  93. GRB 050607: Optical decay and spectral slope
  94. GRB 050607: MDM Observations
  95. GRB050607,optical observation
  96. GRB 050607 - XRT refined data analysis
  97. Optical Afterglow of GRB 050607
  98. GRB050607 optical limit by "Pi of the Sky"
  99. GRB050607: Swift Detection of a long GRB
  100. GRB050607: P60 Observations

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