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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 050716: Lulin B and R band optical observations
  2. GRB050716, optical observation
  3. GRB 050716: Optical Observations
  4. GRB050716: Faulkes North Telescope observation
  5. GRB050716: Correction to sign in XRT coordinate
  6. Swift/BAT detection of GRB 050716
  7. GRB050715: Refined analysis of the Swift-BAT burst
  8. GRB 050715: Swift-BAT detection
  9. Swift UVOT Observations of GRB 050714B
  10. Konus-Wind observation of GRB 050713A
  11. GRB 050714B: refined XRT analysis
  12. GRB 050713b: RTT150 optical observations
  13. GRB 050714B: candidate afterglow does not fade
  14. GRB050714B: Refined analysis of the Swift-BAT burst
  15. GRB 050714B: optical afterglow
  16. Swift detection of a long transient (GRB 050714B?)
  17. GRB 050709: optical afterglow candidate
  18. GRB 050714, R-band candidate
  19. GRB 050714: Swift XRT afterglow position
  20. GRB 050714, optical observations
  21. GRB 050714A: ROTSE-III Optical Limits
  22. GRB 050714 - A long GRB detected with INTEGRAL
  23. GRB 050713A: XRT refined analysis
  24. GRB 050709: Spectroscopy
  25. GRB 050713A: RAPTOR detection of early optical emission
  26. GRB050713B :Swift/UVOT observations
  27. GRB050713b: XRT refined analysis
  28. GRB050712: TNG R-band observations
  29. GRB 050713B: Swift-BAT Refined Analysis
  30. Swift-BAT Trigger 145729 is not a GRB
  31. GRB 050713A: Swift/UVOT observation
  32. GRB 050713A : Swift-BAT Refined Analysis
  33. GRB050712: Swift UVOT Observation of Afterglow Emission
  34. GRB 050713A : Lulin R-band observation
  35. GRB 050713A XMM-Newton observation
  36. GRB 050713b : Lulin R-band observations
  37. GRB050713B: Faulkes North Telescope observation
  38. RBO RI observations of GRB 050713A
  39. GRB 050713B
  40. GRB050709 : Chandra source optical counterpart
  41. GRB050713: Liverpool Telescope prompt observations
  42. GRB 050712, optical observations
  43. GRB 050713 : Planned XMM-Newton observation
  44. GRB050709: Candidate X-ray Afterglow from Chandra
  45. GRB 050713, R-band observations at NOT
  46. GRB 050713: ARC NIR Detections and Identification of Fading
  47. GRB050713: possible I-band afterglow
  48. GRB 050713: Swift detection of Bright Burst
  49. GRB 050713A: ROTSE-III Optical Limits
  50. GRB050712: XRT refined analysis
  51. GRB050709: Radio Observations
  52. GRB 050709: Swift UVOT and XRT observations
  53. GRB 050712: Swift-BAT Refined Analysis
  54. GRB050712: UVOT candidate optical counterpart
  55. GRB 050712: Swift XRT afterglow position
  56. GRB 050712: Swift detection of a weak burst
  57. GRB 050709: LCO40 Observations
  58. GRB050709, optical observations
  59. GRB050709: A Possible Short-Hard GRB Localized by HETE
  60. PROMPT Rc Observations of GRB 050709
  61. GRB 050525a: PROMPT VRcIc Detections
  62. GRB 050525a: ARC 3.5-meter Optical and NIR Observations
  63. GRB 050525a: ARC 3.5-Meter SPIcam Field Calibration
  64. GRB 050626 optical observations
  65. GRB 050626: Swift XRT observations
  66. GRB 050701
  67. GRB 050701, optical observations
  68. GRB 050408: ARC 3.5-meter NIR Observations
  69. GRB 050701: Refined XRT analysis
  70. Swift UVOT observations of GRB 050701
  71. GRB050701: Swift-BAT Refined analysis
  72. GRB 050701: Swift XRT afterglow position
  73. Swift trigger 143708 is really GRB 050701
  74. GRB 050607, radio observations
  75. H11603: An X-ray flare from V4641 Sgr, or a possible XRF
  76. GRB 050626 - Correction to GCN 3552
  77. GRB 050626 - a long GRB detected with INTEGRAL
  78. GRB 050525A: Swift Late-Time Decay Rate
  79. GRB050525a: HST Observations
  80. CORRECTION: GRB050603 Swift UVOT Afterglow Observations
  81. H3804: A Possible New XRB Detected by HETE
  82. H3800 and H3801 on 2005 June 11: two bursts from SGR1806-20 localized by HETE
  83. XRF 050509c: Optical monitoring
  84. Konus-Wind observation of an intermediate burst from SGR 1806-20
  85. IBAS Alert #2512 is NOT a GRB
  86. XRF050509c: Radio Detection
  87. GRB 050416(a): Host Galaxy Redshift Determination
  88. GRB 050607: MDM Observation
  89. GRB 050607 optical decay
  90. GRB 050607: RTT150 optical observations
  91. GRB050607: refined analysis of prompt REM observations
  92. Swift/UVOT observations of GRB050607
  93. GRB 050607 : Lulin R-band observation
  94. GRB 050607: PROMPT VRcIc Observations
  95. GRB 050607: RAPTOR-S Early Optical Limits
  96. GRB050607: KAIT optical limits
  97. GRB 050525a, Mid-Infrared Observations
  98. GRB 050607: Optical decay and spectral slope
  99. GRB 050607: MDM Observations
  100. GRB050607,optical observation

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