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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. GRB050713B :Swift/UVOT observations
  2. GRB050713b: XRT refined analysis
  3. GRB050712: TNG R-band observations
  4. GRB 050713B: Swift-BAT Refined Analysis
  5. Swift-BAT Trigger 145729 is not a GRB
  6. GRB 050713A: Swift/UVOT observation
  7. GRB 050713A : Swift-BAT Refined Analysis
  8. GRB050712: Swift UVOT Observation of Afterglow Emission
  9. GRB 050713A : Lulin R-band observation
  10. GRB 050713A XMM-Newton observation
  11. GRB 050713b : Lulin R-band observations
  12. GRB050713B: Faulkes North Telescope observation
  13. RBO RI observations of GRB 050713A
  14. GRB 050713B
  15. GRB050709 : Chandra source optical counterpart
  16. GRB050713: Liverpool Telescope prompt observations
  17. GRB 050712, optical observations
  18. GRB 050713 : Planned XMM-Newton observation
  19. GRB050709: Candidate X-ray Afterglow from Chandra
  20. GRB 050713, R-band observations at NOT
  21. GRB 050713: ARC NIR Detections and Identification of Fading
  22. GRB050713: possible I-band afterglow
  23. GRB 050713: Swift detection of Bright Burst
  24. GRB 050713A: ROTSE-III Optical Limits
  25. GRB050712: XRT refined analysis
  26. GRB050709: Radio Observations
  27. GRB 050709: Swift UVOT and XRT observations
  28. GRB 050712: Swift-BAT Refined Analysis
  29. GRB050712: UVOT candidate optical counterpart
  30. GRB 050712: Swift XRT afterglow position
  31. GRB 050712: Swift detection of a weak burst
  32. GRB 050709: LCO40 Observations
  33. GRB050709, optical observations
  34. GRB050709: A Possible Short-Hard GRB Localized by HETE
  35. PROMPT Rc Observations of GRB 050709
  36. GRB 050525a: PROMPT VRcIc Detections
  37. GRB 050525a: ARC 3.5-meter Optical and NIR Observations
  38. GRB 050525a: ARC 3.5-Meter SPIcam Field Calibration
  39. GRB 050626 optical observations
  40. GRB 050626: Swift XRT observations
  41. GRB 050701
  42. GRB 050701, optical observations
  43. GRB 050408: ARC 3.5-meter NIR Observations
  44. GRB 050701: Refined XRT analysis
  45. Swift UVOT observations of GRB 050701
  46. GRB050701: Swift-BAT Refined analysis
  47. GRB 050701: Swift XRT afterglow position
  48. Swift trigger 143708 is really GRB 050701
  49. GRB 050607, radio observations
  50. H11603: An X-ray flare from V4641 Sgr, or a possible XRF
  51. GRB 050626 - Correction to GCN 3552
  52. GRB 050626 - a long GRB detected with INTEGRAL
  53. GRB 050525A: Swift Late-Time Decay Rate
  54. GRB050525a: HST Observations
  55. CORRECTION: GRB050603 Swift UVOT Afterglow Observations
  56. H3804: A Possible New XRB Detected by HETE
  57. H3800 and H3801 on 2005 June 11: two bursts from SGR1806-20 localized by HETE
  58. XRF 050509c: Optical monitoring
  59. Konus-Wind observation of an intermediate burst from SGR 1806-20
  60. IBAS Alert #2512 is NOT a GRB
  61. XRF050509c: Radio Detection
  62. GRB 050416(a): Host Galaxy Redshift Determination
  63. GRB 050607: MDM Observation
  64. GRB 050607 optical decay
  65. GRB 050607: RTT150 optical observations
  66. GRB050607: refined analysis of prompt REM observations
  67. Swift/UVOT observations of GRB050607
  68. GRB 050607 : Lulin R-band observation
  69. GRB 050607: PROMPT VRcIc Observations
  70. GRB 050607: RAPTOR-S Early Optical Limits
  71. GRB050607: KAIT optical limits
  72. GRB 050525a, Mid-Infrared Observations
  73. GRB 050607: Optical decay and spectral slope
  74. GRB 050607: MDM Observations
  75. GRB050607,optical observation
  76. GRB 050607 - XRT refined data analysis
  77. Optical Afterglow of GRB 050607
  78. GRB050607 optical limit by "Pi of the Sky"
  79. GRB050607: Swift Detection of a long GRB
  80. GRB050607: P60 Observations
  81. GRB050607: prompt REM observations
  82. GRB 050603: prediction of t_break
  83. Limits on a SN in the field of GRB 050509b
  84. GRB 050603: Redshift
  85. GRB 050603 - XRT data analysis of the first day
  86. Konus-Wind observation of GRB 050603
  87. GRB 050603: Analysis of UVOT data
  88. GRB050603: Fading Afterglow observed by Swift UVOT
  89. GRB050603, submillimetre observations
  90. GRB 050603: Swift XRT Position
  91. GRB050603: Radio Detection
  92. GRB 050603: Swift-BAT refined analysis of a long three-spiked burst
  93. GRB 050603: Afterglow Identification from LCO
  94. GRB 050603: INTEGRAL shows it is not a short GRB
  95. Swift/BAT Detection of GRB050603
  96. GRB 050408: jet break in the XRT light curve
  97. GRB 050525a, infrared observations
  98. GRB 050525a, SMARTS optical/IR afterglow observations
  99. GRB050528, XRT observations
  100. Correction to GCN Circ 3502 on GRB 050528

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Download all Circulars as a .tar.gz archive (updated once a day):
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