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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"

26329 results found.

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

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