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

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