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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"

15987 results found.

  1. GRB 050730, optical observation
  2. GRB050805b: CrAO optical limit
  3. GRB050805a : Null detection report
  4. GRB050730, optical observations
  5. GRB050803, optical observations
  6. GRB 050805b: OHP optical limits
  7. GRB 050805b: TAROT optical limits
  8. GRB050805b: MASTER optical observations
  9. GRB050805a: MASTER optical candidat
  10. GRB050802: TNG optical observations
  11. GRB050803: Radio Observation
  12. GRB 050803: RTT150 optical observations
  13. GRB050801: Radio Observation
  14. GRB050730: Radio Detection
  15. GRB050803: CrAO optical observations, possible OT candidate
  16. GRB050803: Optical/UV Upper Limits from Swift-UVOT
  17. GRB 050802.422: Fading of the afterglow and detection of the host
  18. GRB050803: MASTER further analys
  19. GRB 050803, optical observations
  20. GRB 050803: TAROT optical limits
  21. GRB050803: MASTER optical observations
  22. GRB050802: Tentative absorption redshift
  23. GRB050730: FORS1 and UVES/VLT low- and high-resolution spectroscopy
  24. GRB 050802: Swift/UVOT optical and UV detections
  25. GRB050802: CrAO optical observations
  26. GRB050801: Unchanged decay slope
  27. GRB 050730: OHP optical observations
  28. GRB 050802 : Lulin Optical follow-up observation
  29. GRB050801: Optical photometry and decay index
  30. GRB050801: Swift/UVOT Optical and UV detections
  31. GRB 050801, SMARTS optical/IR afterglow observations
  32. GRB 050801: ROTSE-III Early Afterglow Break
  33. GRB 050730: early TAROT optical observations
  34. GRB 050730: RTT150 optical observations
  35. GRB 050730, spectra and optical photometry
  36. GRB 050730: Swift XRT afterglow observations
  37. GRB050730: confirmation of redshift
  38. GRB 050730, SMARTS optical/IR afterglow observations
  39. GRB050730: Liverpool Telescope optical observations
  40. GRB 050730, optical candidate
  41. GRB050730: Swift-BAT detection of a weak burst
  42. GRB050713b: Maidanak optical observations
  43. GRB 050724: WHT optical observations
  44. GRB050726: Swift UVOT observations
  45. GRB050724: Refined Radio Position
  46. GRB 050724, SMARTS optical/IR afterglow observations
  47. GRB 050726, SMARTS optical/IR observations
  48. GRB 050727: RTT150 optical observations
  49. GRB050727: KAIT optical limit
  50. GRB050709: Second Epoch Chandra Observation
  51. GRB 050724: dust-scattered X-ray halo detected in SWIFT/XRT observation
  52. GRB050724: Further Radio Observations
  53. GRB050726: Swift-BAT detection of a weak burst
  54. GRB 050724: Optical Variability in Nearby Galaxy
  55. GRB 050724: Optical limit
  56. GRB 050724: optical and near-IR observations
  57. GRB 050724: Optical imaging/astrometry
  58. GRB 050724: RTT150 optical observations
  59. GRB 050724: early Swift XRT analysis results
  60. GRB050721A: optical decay
  61. GRB 050721: optical afterglow confirmed
  62. Swift BAT Trigger 146986 is SWIFT J1753.5-0127
  63. GRB 050721a: Optical Observations
  64. GRB 050709: Refined Spectral and Temporal Properties
  65. GRB050712: Radio Observations
  66. GRB050713a: Radio Observation
  67. GRB 050712, Tautenburg optical afterglow observations
  68. Swift-BAT detection of a possible GRB
  69. GRB050712: optical limits
  70. Swift detection of GRB 050717
  71. GRB 050716: Lulin B and R band optical observations
  72. GRB050716, optical observation
  73. GRB 050716: Optical Observations
  74. Swift/BAT detection of GRB 050716
  75. GRB 050713b: RTT150 optical observations
  76. GRB 050714B: candidate afterglow does not fade
  77. GRB 050714B: optical afterglow
  78. Swift detection of a long transient (GRB 050714B?)
  79. GRB 050709: optical afterglow candidate
  80. GRB 050714, optical observations
  81. GRB 050714A: ROTSE-III Optical Limits
  82. GRB 050709: Spectroscopy
  83. GRB 050713A: RAPTOR detection of early optical emission
  84. GRB050712: Swift UVOT Observation of Afterglow Emission
  85. GRB 050713B
  86. GRB050709 : Chandra source optical counterpart
  87. GRB 050712, optical observations
  88. GRB050709: Candidate X-ray Afterglow from Chandra
  89. GRB 050713, R-band observations at NOT
  90. GRB 050713: Swift detection of Bright Burst
  91. GRB 050713A: ROTSE-III Optical Limits
  92. GRB 050709: Swift UVOT and XRT observations
  93. GRB050712: UVOT candidate optical counterpart
  94. GRB 050712: Swift detection of a weak burst
  95. GRB050709, optical observations
  96. GRB050709: A Possible Short-Hard GRB Localized by HETE
  97. GRB 050525a: ARC 3.5-meter Optical and NIR Observations
  98. GRB 050525a: ARC 3.5-Meter SPIcam Field Calibration
  99. GRB 050626 optical observations
  100. GRB 050626: Swift XRT observations

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