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

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