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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"

27907 results found.

  1. GRB050813, SDSS pre-burst observations
  2. GRB 050813: Swift-BAT refined analysis
  3. GRB 050813: Photometry of object in XRT error circle
  4. GRB050813: SWIFT/UVOT observation
  5. GRB 050813: Swift XRT afterglow localization
  6. Ongoing activity of SGR 1806-20: an intermediate burst 050811
  7. Detection of an intermediate burst from SGR 1806-20 on August 8
  8. GRB050805b: CrAO optical limit
  9. GRB050803, optical observations
  10. Retraction of Swift Trigger 149131 (GRB 050805B)
  11. GRB 050805b: OHP optical limits
  12. GRB 050805b: TAROT optical limits
  13. GRB050805b: MASTER optical observations
  14. Possible GRB 050805B: Swift-BAT trigger 149131 may be a burst
  15. GRB050805a: MASTER optical candidat
  16. GRB050802: TNG optical observations
  17. GRB050803: Radio Observation
  18. GRB 050803: RTT150 optical observations
  19. GRB050801: Radio Observation
  20. GRB050730: Radio Detection
  21. GRB 050803: Keck Observations
  22. GRB 050803: Swift-BAT refined analysis
  23. GRB 050802.422: Fading of the afterglow and detection of the host
  24. GRB 050803: early Swift XRT analysis results
  25. GRB 050803: TAROT optical limits
  26. GCN GRB observation 050713A
  27. GRB050730: FORS1 and UVES/VLT low- and high-resolution spectroscopy
  28. GRB050802 radio non-detection
  29. GRB 050730: OHP optical observations
  30. GRB 050802: early Swift XRT analysis results
  31. GRB 050802: Swift/UVOT observations
  32. GRB 050802: Swift-BAT refined analysis
  33. GRB050801: Optical photometry and decay index
  34. GRB 050802: Swift Gamma-ray Burst
  35. GRB050801: Swift/UVOT Optical and UV detections
  36. GRB 050730: Preliminary Analysis of MIKE Spectrum
  37. GCN 050801: early Swift XRT analysis results
  38. GRB 050801: Swift-BAT refined analysis
  39. GRB 050730: XRT refined analysis
  40. GRB 050730: early TAROT optical observations
  41. GRB 050730, spectra and optical photometry
  42. GRB050730: Refined BAT analysis of the Swift-BAT burst
  43. GRB 050730 XMM-Newton observation
  44. GRB050730: Swift-BAT detection of a weak burst
  45. GRB050713b: Maidanak optical observations
  46. GRB 050724: Secure Host Redshift from Keck
  47. GRB 050724: WHT optical observations
  48. GRB050713: analysis of the XMM-Newton observation
  49. Swift-BAT trigger 147918 is not a real GRB
  50. GRB050724: VLT observations of the variable source
  51. GRB050709: Second Epoch Chandra Observation
  52. GRB050726: Swift-BAT detection of a weak burst
  53. GRB 050724: Optical Variability in Nearby Galaxy
  54. GRB 050724: J-band observations
  55. GRB 050724: GMOS Imaging and Spectroscopy
  56. GRB050724: Radio Observation
  57. GRB 050724: Optical imaging/astrometry
  58. GRB 050724: Swift/UVOT Upper Limit
  59. GRB050724: Refined analysis of the Swift-BAT possible short burst
  60. GRB 050724: possible host galaxy in DSS
  61. GRB 050721A: Swift-BAT refined analysis
  62. GRB 050721A: Early Swift XRT analysis results
  63. GRB050721A: optical decay
  64. GRB 050721: optical afterglow confirmed
  65. GRB 050709: Refined Spectral and Temporal Properties
  66. GRB050714b: Radio Observation
  67. GRB050712: Radio Observations
  68. GRB050713a: Radio Observation
  69. GRB 050712, Tautenburg optical afterglow observations
  70. Swift-BAT detection of a possible GRB
  71. GRB 050714B: VLT R-band observations
  72. GRB 050717: Additional LCO observations
  73. GRB 050716; J-band observations
  74. GRB 050717: LCO near-IR observations
  75. Swift/UVOT Observations of GRB 050717
  76. GRB 050717: Swift-BAT refined analysis
  77. GRB050717: Swift XRT position
  78. Swift detection of GRB 050717
  79. Swift UVOT Observations of GRB 050716
  80. GRB 050716: Refined XRT analysis.
  81. GRB050716: Refined analysis of the Swift-BAT burst
  82. GRB 050716: Lulin B and R band optical observations
  83. GRB050716, optical observation
  84. GRB050716: Faulkes North Telescope observation
  85. GRB050715: Refined analysis of the Swift-BAT burst
  86. GRB 050715: Swift-BAT detection
  87. GRB 050713b: RTT150 optical observations
  88. GRB050714B: Refined analysis of the Swift-BAT burst
  89. GRB 050714B: optical afterglow
  90. GRB 050714, R-band candidate
  91. GRB 050714, optical observations
  92. GRB 050713A: XRT refined analysis
  93. GRB 050713A: RAPTOR detection of early optical emission
  94. GRB050713B :Swift/UVOT observations
  95. GRB050713b: XRT refined analysis
  96. GRB050712: TNG R-band observations
  97. GRB 050713B: Swift-BAT Refined Analysis
  98. GRB 050713A: Swift/UVOT observation
  99. GRB 050713A : Swift-BAT Refined Analysis
  100. GRB050712: Swift UVOT Observation of Afterglow Emission

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