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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 050717: Additional LCO observations
  2. GRB050717
  3. GRB 050716; J-band observations
  4. Konus-Wind observation of GRB 050717
  5. GRB 050717: LCO near-IR observations
  6. Swift/UVOT Observations of GRB 050717
  7. GRB 050717: Swift-BAT refined analysis
  8. GRB 050717: Refined XRT analysis.
  9. GRB050712: optical limits
  10. GRB050717: Swift XRT position
  11. Swift detection of GRB 050717
  12. GRB 050716 - UKIRT identification of candidate afterglow
  13. Swift UVOT Observations of GRB 050716
  14. GRB 050716: Refined XRT analysis.
  15. GRB050716: Refined analysis of the Swift-BAT burst
  16. GRB 050716: Lulin B and R band optical observations
  17. GRB050716, optical observation
  18. GRB 050716: Optical Observations
  19. GRB050716: Faulkes North Telescope observation
  20. GRB050716: Correction to sign in XRT coordinate
  21. Swift/BAT detection of GRB 050716
  22. GRB050715: Refined analysis of the Swift-BAT burst
  23. GRB 050715: Swift-BAT detection
  24. Swift UVOT Observations of GRB 050714B
  25. Konus-Wind observation of GRB 050713A
  26. GRB 050714B: refined XRT analysis
  27. GRB 050713b: RTT150 optical observations
  28. GRB 050714B: candidate afterglow does not fade
  29. GRB050714B: Refined analysis of the Swift-BAT burst
  30. GRB 050714B: optical afterglow
  31. Swift detection of a long transient (GRB 050714B?)
  32. GRB 050709: optical afterglow candidate
  33. GRB 050714, R-band candidate
  34. GRB 050714: Swift XRT afterglow position
  35. GRB 050714, optical observations
  36. GRB 050714A: ROTSE-III Optical Limits
  37. GRB 050714 - A long GRB detected with INTEGRAL
  38. GRB 050713A: XRT refined analysis
  39. GRB 050709: Spectroscopy
  40. GRB 050713A: RAPTOR detection of early optical emission
  41. GRB050713B :Swift/UVOT observations
  42. GRB050713b: XRT refined analysis
  43. GRB050712: TNG R-band observations
  44. GRB 050713B: Swift-BAT Refined Analysis
  45. Swift-BAT Trigger 145729 is not a GRB
  46. GRB 050713A: Swift/UVOT observation
  47. GRB 050713A : Swift-BAT Refined Analysis
  48. GRB050712: Swift UVOT Observation of Afterglow Emission
  49. GRB 050713A : Lulin R-band observation
  50. GRB 050713A XMM-Newton observation
  51. GRB 050713b : Lulin R-band observations
  52. GRB050713B: Faulkes North Telescope observation
  53. RBO RI observations of GRB 050713A
  54. GRB 050713B
  55. GRB050709 : Chandra source optical counterpart
  56. GRB050713: Liverpool Telescope prompt observations
  57. GRB 050712, optical observations
  58. GRB 050713 : Planned XMM-Newton observation
  59. GRB050709: Candidate X-ray Afterglow from Chandra
  60. GRB 050713, R-band observations at NOT
  61. GRB 050713: ARC NIR Detections and Identification of Fading
  62. GRB050713: possible I-band afterglow
  63. GRB 050713: Swift detection of Bright Burst
  64. GRB 050713A: ROTSE-III Optical Limits
  65. GRB050712: XRT refined analysis
  66. GRB050709: Radio Observations
  67. GRB 050709: Swift UVOT and XRT observations
  68. GRB 050712: Swift-BAT Refined Analysis
  69. GRB050712: UVOT candidate optical counterpart
  70. GRB 050712: Swift XRT afterglow position
  71. GRB 050712: Swift detection of a weak burst
  72. GRB 050709: LCO40 Observations
  73. GRB050709, optical observations
  74. GRB050709: A Possible Short-Hard GRB Localized by HETE
  75. PROMPT Rc Observations of GRB 050709
  76. GRB 050525a: PROMPT VRcIc Detections
  77. GRB 050525a: ARC 3.5-meter Optical and NIR Observations
  78. GRB 050525a: ARC 3.5-Meter SPIcam Field Calibration
  79. GRB 050626 optical observations
  80. GRB 050626: Swift XRT observations
  81. GRB 050701
  82. GRB 050701, optical observations
  83. GRB 050408: ARC 3.5-meter NIR Observations
  84. GRB 050701: Refined XRT analysis
  85. Swift UVOT observations of GRB 050701
  86. GRB050701: Swift-BAT Refined analysis
  87. GRB 050701: Swift XRT afterglow position
  88. Swift trigger 143708 is really GRB 050701
  89. GRB 050607, radio observations
  90. H11603: An X-ray flare from V4641 Sgr, or a possible XRF
  91. GRB 050626 - Correction to GCN 3552
  92. GRB 050626 - a long GRB detected with INTEGRAL
  93. GRB 050525A: Swift Late-Time Decay Rate
  94. GRB050525a: HST Observations
  95. CORRECTION: GRB050603 Swift UVOT Afterglow Observations
  96. H3804: A Possible New XRB Detected by HETE
  97. H3800 and H3801 on 2005 June 11: two bursts from SGR1806-20 localized by HETE
  98. XRF 050509c: Optical monitoring
  99. Konus-Wind observation of an intermediate burst from SGR 1806-20
  100. IBAS Alert #2512 is NOT a GRB

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