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

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