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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"

16159 results found.

  1. GRB050709: Second Epoch Chandra Observation
  2. GRB 050724: dust-scattered X-ray halo detected in SWIFT/XRT observation
  3. GRB050724: Further Radio Observations
  4. GRB050726: Swift-BAT detection of a weak burst
  5. GRB 050724: Optical Variability in Nearby Galaxy
  6. GRB 050724: Optical limit
  7. GRB 050724: optical and near-IR observations
  8. GRB 050724: Optical imaging/astrometry
  9. GRB 050724: RTT150 optical observations
  10. GRB 050724: early Swift XRT analysis results
  11. GRB050721A: optical decay
  12. GRB 050721: optical afterglow confirmed
  13. Swift BAT Trigger 146986 is SWIFT J1753.5-0127
  14. GRB 050721a: Optical Observations
  15. GRB 050709: Refined Spectral and Temporal Properties
  16. GRB050712: Radio Observations
  17. GRB050713a: Radio Observation
  18. GRB 050712, Tautenburg optical afterglow observations
  19. Swift-BAT detection of a possible GRB
  20. GRB050712: optical limits
  21. Swift detection of GRB 050717
  22. GRB 050716: Lulin B and R band optical observations
  23. GRB050716, optical observation
  24. GRB 050716: Optical Observations
  25. Swift/BAT detection of GRB 050716
  26. GRB 050713b: RTT150 optical observations
  27. GRB 050714B: candidate afterglow does not fade
  28. GRB 050714B: optical afterglow
  29. Swift detection of a long transient (GRB 050714B?)
  30. GRB 050709: optical afterglow candidate
  31. GRB 050714, optical observations
  32. GRB 050714A: ROTSE-III Optical Limits
  33. GRB 050709: Spectroscopy
  34. GRB 050713A: RAPTOR detection of early optical emission
  35. GRB050712: Swift UVOT Observation of Afterglow Emission
  36. GRB 050713B
  37. GRB050709 : Chandra source optical counterpart
  38. GRB 050712, optical observations
  39. GRB050709: Candidate X-ray Afterglow from Chandra
  40. GRB 050713, R-band observations at NOT
  41. GRB 050713: Swift detection of Bright Burst
  42. GRB 050713A: ROTSE-III Optical Limits
  43. GRB 050709: Swift UVOT and XRT observations
  44. GRB050712: UVOT candidate optical counterpart
  45. GRB 050712: Swift detection of a weak burst
  46. GRB050709, optical observations
  47. GRB050709: A Possible Short-Hard GRB Localized by HETE
  48. GRB 050525a: ARC 3.5-meter Optical and NIR Observations
  49. GRB 050525a: ARC 3.5-Meter SPIcam Field Calibration
  50. GRB 050626 optical observations
  51. GRB 050626: Swift XRT observations
  52. GRB 050701, optical observations
  53. GRB 050607, radio observations
  54. H11603: An X-ray flare from V4641 Sgr, or a possible XRF
  55. GRB 050525A: Swift Late-Time Decay Rate
  56. H3804: A Possible New XRB Detected by HETE
  57. H3800 and H3801 on 2005 June 11: two bursts from SGR1806-20 localized by HETE
  58. XRF 050509c: Optical monitoring
  59. XRF050509c: Radio Detection
  60. GRB 050607 optical decay
  61. GRB 050607: RTT150 optical observations
  62. GRB050607: refined analysis of prompt REM observations
  63. Swift/UVOT observations of GRB050607
  64. GRB 050607: RAPTOR-S Early Optical Limits
  65. GRB050607: KAIT optical limits
  66. GRB 050525a, Mid-Infrared Observations
  67. GRB 050607: Optical decay and spectral slope
  68. GRB 050607: MDM Observations
  69. GRB050607,optical observation
  70. GRB 050607 - XRT refined data analysis
  71. Optical Afterglow of GRB 050607
  72. GRB050607 optical limit by "Pi of the Sky"
  73. GRB050607: prompt REM observations
  74. GRB050603: Fading Afterglow observed by Swift UVOT
  75. GRB 050603: Swift XRT Position
  76. GRB050603: Radio Detection
  77. GRB 050525a, SMARTS optical/IR afterglow observations
  78. GRB050528: BOOTES optical candidate (retraction)
  79. GRB050528: BOOTES optical candidate
  80. GRB050525a: Radio Observations
  81. GRB 050525: RTT150, Optical observations
  82. GRB050525a: optical upper limits
  83. GRB 050525a: SARA Observations
  84. GRB 050525: MITSuME Optical Observation in VRI
  85. GRB 050525a: MDM Observations
  86. GRB050525A,optical observation
  87. GRB 050525 : Lulin optical afterglow observations
  88. GRB050525: Super-LOTIS observations
  89. GRB 050525a: Gemini/GMOS Spectra
  90. GRB050306: optical afterglow not confirmed
  91. GRB 050525: BART optical observation
  92. GRB 050525A: BOOTES simultaneous optical observations
  93. GRB 050525A: Swift-BAT refined analysis
  94. GRB050525: Optical observations
  95. Swift/UVOT UV and optical detections of GRB 050525
  96. GRB 050525, infrared observations
  97. GRB 050525: Optical observation
  98. GRB 050525: observatons of the optical afterglow
  99. GRB 050525: Swift Detection of a Bright, Possibly Short Burst
  100. GRB 050509A: Further I-band imaging

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