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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"

26328 results found.

  1. GRB 050820: Swift detection of a GRB
  2. GRB 050819 Swift-BAT refined analysis
  3. GRB050819: Swift-BAT detection of a weak burst
  4. GRB 050817: Optical observations
  5. GRB050817: Negative Optical Observations
  6. GRB 050814: continued fading
  7. GRB050815: Optical afterglow detection by Swift UVOT
  8. GRB050815: XRT refined analysis
  9. GRB050815: Refined analysis of the Swift-BAT burst
  10. GRB 050815: ROTSE-III Optical Limits
  11. GRB050815: Swift-BAT detection of a burst
  12. GRB050814: Fading red source
  13. GRB050814: P60 Optical Afterglow Candidate
  14. GRB 050813: Non-fading of afterglow candidate
  15. GRB 050814: XRT refined analysis
  16. GRB050814: SWIFT/UVOT observation
  17. GRB050814: Refined analysis of the Swift-BAT burst
  18. GRB 050813: Gemini spectroscopy and redshifts of galaxies B and C
  19. GRB 050814: Swift XRT Afterglow Localization
  20. GRB 050814: Swift detection of a burst
  21. GRB 050813: Magellan detection of a high redshift galaxy cluster
  22. GRB050813, SDSS pre-burst observations
  23. GRB 050813: Swift-BAT refined analysis
  24. GRB 050813: Photometry of object in XRT error circle
  25. GRB050813: SWIFT/UVOT observation
  26. GRB 050813: Swift XRT afterglow localization
  27. Ongoing activity of SGR 1806-20: an intermediate burst 050811
  28. Detection of an intermediate burst from SGR 1806-20 on August 8
  29. GRB050805b: CrAO optical limit
  30. GRB050803, optical observations
  31. Retraction of Swift Trigger 149131 (GRB 050805B)
  32. GRB 050805b: OHP optical limits
  33. GRB 050805b: TAROT optical limits
  34. GRB050805b: MASTER optical observations
  35. Possible GRB 050805B: Swift-BAT trigger 149131 may be a burst
  36. GRB050805a: MASTER optical candidat
  37. GRB050802: TNG optical observations
  38. GRB050803: Radio Observation
  39. GRB 050803: RTT150 optical observations
  40. GRB050801: Radio Observation
  41. GRB050730: Radio Detection
  42. GRB 050803: Keck Observations
  43. GRB 050803: Swift-BAT refined analysis
  44. GRB 050802.422: Fading of the afterglow and detection of the host
  45. GRB 050803: early Swift XRT analysis results
  46. GRB 050803: TAROT optical limits
  47. GCN GRB observation 050713A
  48. GRB050730: FORS1 and UVES/VLT low- and high-resolution spectroscopy
  49. GRB050802 radio non-detection
  50. GRB 050730: OHP optical observations
  51. GRB 050802: early Swift XRT analysis results
  52. GRB 050802: Swift/UVOT observations
  53. GRB 050802: Swift-BAT refined analysis
  54. GRB050801: Optical photometry and decay index
  55. GRB 050802: Swift Gamma-ray Burst
  56. GRB050801: Swift/UVOT Optical and UV detections
  57. GRB 050730: Preliminary Analysis of MIKE Spectrum
  58. GCN 050801: early Swift XRT analysis results
  59. GRB 050801: Swift-BAT refined analysis
  60. GRB 050730: XRT refined analysis
  61. GRB 050730: early TAROT optical observations
  62. GRB 050730, spectra and optical photometry
  63. GRB050730: Refined BAT analysis of the Swift-BAT burst
  64. GRB 050730 XMM-Newton observation
  65. GRB050730: Swift-BAT detection of a weak burst
  66. GRB050713b: Maidanak optical observations
  67. GRB 050724: Secure Host Redshift from Keck
  68. GRB 050724: WHT optical observations
  69. GRB050713: analysis of the XMM-Newton observation
  70. Swift-BAT trigger 147918 is not a real GRB
  71. GRB050724: VLT observations of the variable source
  72. GRB050709: Second Epoch Chandra Observation
  73. GRB050726: Swift-BAT detection of a weak burst
  74. GRB 050724: Optical Variability in Nearby Galaxy
  75. GRB 050724: J-band observations
  76. GRB 050724: GMOS Imaging and Spectroscopy
  77. GRB050724: Radio Observation
  78. GRB 050724: Optical imaging/astrometry
  79. GRB 050724: Swift/UVOT Upper Limit
  80. GRB050724: Refined analysis of the Swift-BAT possible short burst
  81. GRB 050724: possible host galaxy in DSS
  82. GRB 050721A: Swift-BAT refined analysis
  83. GRB 050721A: Early Swift XRT analysis results
  84. GRB050721A: optical decay
  85. GRB 050721: optical afterglow confirmed
  86. GRB 050709: Refined Spectral and Temporal Properties
  87. GRB050714b: Radio Observation
  88. GRB050712: Radio Observations
  89. GRB050713a: Radio Observation
  90. GRB 050712, Tautenburg optical afterglow observations
  91. Swift-BAT detection of a possible GRB
  92. GRB 050714B: VLT R-band observations
  93. GRB 050717: Additional LCO observations
  94. GRB 050716; J-band observations
  95. GRB 050717: LCO near-IR observations
  96. Swift/UVOT Observations of GRB 050717
  97. GRB 050717: Swift-BAT refined analysis
  98. GRB050717: Swift XRT position
  99. Swift detection of GRB 050717
  100. Swift UVOT Observations of GRB 050716

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