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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. GRB050717
  2. GRB 050716; J-band observations
  3. Konus-Wind observation of GRB 050717
  4. GRB 050717: LCO near-IR observations
  5. Swift/UVOT Observations of GRB 050717
  6. GRB 050717: Swift-BAT refined analysis
  7. GRB 050717: Refined XRT analysis.
  8. GRB050712: optical limits
  9. GRB050717: Swift XRT position
  10. Swift detection of GRB 050717
  11. GRB 050716 - UKIRT identification of candidate afterglow
  12. Swift UVOT Observations of GRB 050716
  13. GRB 050716: Refined XRT analysis.
  14. GRB050716: Refined analysis of the Swift-BAT burst
  15. GRB 050716: Lulin B and R band optical observations
  16. GRB050716, optical observation
  17. GRB 050716: Optical Observations
  18. GRB050716: Faulkes North Telescope observation
  19. GRB050716: Correction to sign in XRT coordinate
  20. Swift/BAT detection of GRB 050716
  21. GRB050715: Refined analysis of the Swift-BAT burst
  22. GRB 050715: Swift-BAT detection
  23. Swift UVOT Observations of GRB 050714B
  24. Konus-Wind observation of GRB 050713A
  25. GRB 050714B: refined XRT analysis
  26. GRB 050713b: RTT150 optical observations
  27. GRB 050714B: candidate afterglow does not fade
  28. GRB050714B: Refined analysis of the Swift-BAT burst
  29. GRB 050714B: optical afterglow
  30. Swift detection of a long transient (GRB 050714B?)
  31. GRB 050709: optical afterglow candidate
  32. GRB 050714, R-band candidate
  33. GRB 050714: Swift XRT afterglow position
  34. GRB 050714, optical observations
  35. GRB 050714A: ROTSE-III Optical Limits
  36. GRB 050714 - A long GRB detected with INTEGRAL
  37. GRB 050713A: XRT refined analysis
  38. GRB 050709: Spectroscopy
  39. GRB 050713A: RAPTOR detection of early optical emission
  40. GRB050713B :Swift/UVOT observations
  41. GRB050713b: XRT refined analysis
  42. GRB050712: TNG R-band observations
  43. GRB 050713B: Swift-BAT Refined Analysis
  44. Swift-BAT Trigger 145729 is not a GRB
  45. GRB 050713A: Swift/UVOT observation
  46. GRB 050713A : Swift-BAT Refined Analysis
  47. GRB050712: Swift UVOT Observation of Afterglow Emission
  48. GRB 050713A : Lulin R-band observation
  49. GRB 050713A XMM-Newton observation
  50. GRB 050713b : Lulin R-band observations
  51. GRB050713B: Faulkes North Telescope observation
  52. RBO RI observations of GRB 050713A
  53. GRB 050713B
  54. GRB050709 : Chandra source optical counterpart
  55. GRB050713: Liverpool Telescope prompt observations
  56. GRB 050712, optical observations
  57. GRB 050713 : Planned XMM-Newton observation
  58. GRB050709: Candidate X-ray Afterglow from Chandra
  59. GRB 050713, R-band observations at NOT
  60. GRB 050713: ARC NIR Detections and Identification of Fading
  61. GRB050713: possible I-band afterglow
  62. GRB 050713: Swift detection of Bright Burst
  63. GRB 050713A: ROTSE-III Optical Limits
  64. GRB050712: XRT refined analysis
  65. GRB050709: Radio Observations
  66. GRB 050709: Swift UVOT and XRT observations
  67. GRB 050712: Swift-BAT Refined Analysis
  68. GRB050712: UVOT candidate optical counterpart
  69. GRB 050712: Swift XRT afterglow position
  70. GRB 050712: Swift detection of a weak burst
  71. GRB 050709: LCO40 Observations
  72. GRB050709, optical observations
  73. GRB050709: A Possible Short-Hard GRB Localized by HETE
  74. PROMPT Rc Observations of GRB 050709
  75. GRB 050525a: PROMPT VRcIc Detections
  76. GRB 050525a: ARC 3.5-meter Optical and NIR Observations
  77. GRB 050525a: ARC 3.5-Meter SPIcam Field Calibration
  78. GRB 050626 optical observations
  79. GRB 050626: Swift XRT observations
  80. GRB 050701
  81. GRB 050701, optical observations
  82. GRB 050408: ARC 3.5-meter NIR Observations
  83. GRB 050701: Refined XRT analysis
  84. Swift UVOT observations of GRB 050701
  85. GRB050701: Swift-BAT Refined analysis
  86. GRB 050701: Swift XRT afterglow position
  87. Swift trigger 143708 is really GRB 050701
  88. GRB 050607, radio observations
  89. H11603: An X-ray flare from V4641 Sgr, or a possible XRF
  90. GRB 050626 - Correction to GCN 3552
  91. GRB 050626 - a long GRB detected with INTEGRAL
  92. GRB 050525A: Swift Late-Time Decay Rate
  93. GRB050525a: HST Observations
  94. CORRECTION: GRB050603 Swift UVOT Afterglow Observations
  95. H3804: A Possible New XRB Detected by HETE
  96. H3800 and H3801 on 2005 June 11: two bursts from SGR1806-20 localized by HETE
  97. XRF 050509c: Optical monitoring
  98. Konus-Wind observation of an intermediate burst from SGR 1806-20
  99. IBAS Alert #2512 is NOT a GRB
  100. XRF050509c: Radio Detection

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