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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"

37524 results found.

  1. GRB 050717: Swift-BAT refined analysis
  2. GRB 050717: Refined XRT analysis.
  3. GRB050712: optical limits
  4. Swift detection of GRB 050717
  5. GRB 050716 - UKIRT identification of candidate afterglow
  6. Swift UVOT Observations of GRB 050716
  7. GRB 050716: Refined XRT analysis.
  8. GRB 050716: Lulin B and R band optical observations
  9. GRB050716, optical observation
  10. GRB 050716: Optical Observations
  11. GRB050716: Faulkes North Telescope observation
  12. Swift/BAT detection of GRB 050716
  13. GRB 050715: Swift-BAT detection
  14. Swift UVOT Observations of GRB 050714B
  15. Konus-Wind observation of GRB 050713A
  16. GRB 050714B: refined XRT analysis
  17. GRB 050713b: RTT150 optical observations
  18. GRB 050714B: candidate afterglow does not fade
  19. GRB050714B: Refined analysis of the Swift-BAT burst
  20. GRB 050714B: optical afterglow
  21. Swift detection of a long transient (GRB 050714B?)
  22. GRB 050709: optical afterglow candidate
  23. GRB 050714, R-band candidate
  24. GRB 050714: Swift XRT afterglow position
  25. GRB 050714, optical observations
  26. GRB 050714A: ROTSE-III Optical Limits
  27. GRB 050714 - A long GRB detected with INTEGRAL
  28. GRB 050713A: XRT refined analysis
  29. GRB 050709: Spectroscopy
  30. GRB 050713A: RAPTOR detection of early optical emission
  31. GRB050713B :Swift/UVOT observations
  32. GRB050712: TNG R-band observations
  33. GRB 050713B: Swift-BAT Refined Analysis
  34. Swift-BAT Trigger 145729 is not a GRB
  35. GRB 050713A: Swift/UVOT observation
  36. GRB 050713A : Swift-BAT Refined Analysis
  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. GRB 050709: Swift UVOT and XRT observations
  54. GRB 050712: Swift-BAT Refined Analysis
  55. GRB 050712: Swift XRT afterglow position
  56. GRB 050712: Swift detection of a weak burst
  57. GRB 050709: LCO40 Observations
  58. GRB050709: A Possible Short-Hard GRB Localized by HETE
  59. PROMPT Rc Observations of GRB 050709
  60. GRB 050525a: PROMPT VRcIc Detections
  61. GRB 050525a: ARC 3.5-meter Optical and NIR Observations
  62. GRB 050525a: ARC 3.5-Meter SPIcam Field Calibration
  63. GRB 050626 optical observations
  64. GRB 050626: Swift XRT observations
  65. GRB 050701
  66. GRB 050701, optical observations
  67. GRB 050408: ARC 3.5-meter NIR Observations
  68. GRB 050701: Refined XRT analysis
  69. Swift UVOT observations of GRB 050701
  70. GRB 050701: Swift XRT afterglow position
  71. Swift trigger 143708 is really GRB 050701
  72. GRB 050607, radio observations
  73. GRB 050626 - Correction to GCN 3552
  74. GRB 050626 - a long GRB detected with INTEGRAL
  75. GRB 050525A: Swift Late-Time Decay Rate
  76. H3804: A Possible New XRB Detected by HETE
  77. XRF 050509c: Optical monitoring
  78. IBAS Alert #2512 is NOT a GRB
  79. GRB 050416(a): Host Galaxy Redshift Determination
  80. GRB 050607: MDM Observation
  81. GRB 050607 optical decay
  82. GRB 050607: RTT150 optical observations
  83. GRB 050607 : Lulin R-band observation
  84. GRB 050607: PROMPT VRcIc Observations
  85. GRB 050607: RAPTOR-S Early Optical Limits
  86. GRB 050525a, Mid-Infrared Observations
  87. GRB 050607: Optical decay and spectral slope
  88. GRB 050607: MDM Observations
  89. GRB050607,optical observation
  90. GRB 050607 - XRT refined data analysis
  91. Optical Afterglow of GRB 050607
  92. GRB050607 optical limit by "Pi of the Sky"
  93. GRB050607: Swift Detection of a long GRB
  94. GRB050607: P60 Observations
  95. GRB 050603: prediction of t_break
  96. Limits on a SN in the field of GRB 050509b
  97. GRB 050603: Redshift
  98. GRB 050603 - XRT data analysis of the first day
  99. Konus-Wind observation of GRB 050603
  100. GRB 050603: Analysis of UVOT data

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