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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"

26324 results found.

  1. GRB050817: Negative Optical Observations
  2. GRB 050814: continued fading
  3. GRB050815: Optical afterglow detection by Swift UVOT
  4. GRB050815: XRT refined analysis
  5. GRB050815: Refined analysis of the Swift-BAT burst
  6. GRB 050815: ROTSE-III Optical Limits
  7. GRB050815: Swift-BAT detection of a burst
  8. GRB050814: Fading red source
  9. GRB050814: P60 Optical Afterglow Candidate
  10. GRB 050813: Non-fading of afterglow candidate
  11. GRB 050814: XRT refined analysis
  12. GRB050814: SWIFT/UVOT observation
  13. GRB050814: Refined analysis of the Swift-BAT burst
  14. GRB 050813: Gemini spectroscopy and redshifts of galaxies B and C
  15. GRB 050814: Swift XRT Afterglow Localization
  16. GRB 050814: Swift detection of a burst
  17. GRB 050813: Magellan detection of a high redshift galaxy cluster
  18. GRB050813, SDSS pre-burst observations
  19. GRB 050813: Swift-BAT refined analysis
  20. GRB 050813: Photometry of object in XRT error circle
  21. GRB050813: SWIFT/UVOT observation
  22. GRB 050813: Swift XRT afterglow localization
  23. Ongoing activity of SGR 1806-20: an intermediate burst 050811
  24. Detection of an intermediate burst from SGR 1806-20 on August 8
  25. GRB050805b: CrAO optical limit
  26. GRB050803, optical observations
  27. Retraction of Swift Trigger 149131 (GRB 050805B)
  28. GRB 050805b: OHP optical limits
  29. GRB 050805b: TAROT optical limits
  30. GRB050805b: MASTER optical observations
  31. Possible GRB 050805B: Swift-BAT trigger 149131 may be a burst
  32. GRB050805a: MASTER optical candidat
  33. GRB050802: TNG optical observations
  34. GRB050803: Radio Observation
  35. GRB 050803: RTT150 optical observations
  36. GRB050801: Radio Observation
  37. GRB050730: Radio Detection
  38. GRB 050803: Keck Observations
  39. GRB 050803: Swift-BAT refined analysis
  40. GRB 050802.422: Fading of the afterglow and detection of the host
  41. GRB 050803: early Swift XRT analysis results
  42. GRB 050803: TAROT optical limits
  43. GCN GRB observation 050713A
  44. GRB050730: FORS1 and UVES/VLT low- and high-resolution spectroscopy
  45. GRB050802 radio non-detection
  46. GRB 050730: OHP optical observations
  47. GRB 050802: early Swift XRT analysis results
  48. GRB 050802: Swift/UVOT observations
  49. GRB 050802: Swift-BAT refined analysis
  50. GRB050801: Optical photometry and decay index
  51. GRB 050802: Swift Gamma-ray Burst
  52. GRB050801: Swift/UVOT Optical and UV detections
  53. GRB 050730: Preliminary Analysis of MIKE Spectrum
  54. GCN 050801: early Swift XRT analysis results
  55. GRB 050801: Swift-BAT refined analysis
  56. GRB 050730: XRT refined analysis
  57. GRB 050730: early TAROT optical observations
  58. GRB 050730, spectra and optical photometry
  59. GRB050730: Refined BAT analysis of the Swift-BAT burst
  60. GRB 050730 XMM-Newton observation
  61. GRB050730: Swift-BAT detection of a weak burst
  62. GRB050713b: Maidanak optical observations
  63. GRB 050724: Secure Host Redshift from Keck
  64. GRB 050724: WHT optical observations
  65. GRB050713: analysis of the XMM-Newton observation
  66. Swift-BAT trigger 147918 is not a real GRB
  67. GRB050724: VLT observations of the variable source
  68. GRB050709: Second Epoch Chandra Observation
  69. GRB050726: Swift-BAT detection of a weak burst
  70. GRB 050724: Optical Variability in Nearby Galaxy
  71. GRB 050724: J-band observations
  72. GRB 050724: GMOS Imaging and Spectroscopy
  73. GRB050724: Radio Observation
  74. GRB 050724: Optical imaging/astrometry
  75. GRB 050724: Swift/UVOT Upper Limit
  76. GRB050724: Refined analysis of the Swift-BAT possible short burst
  77. GRB 050724: possible host galaxy in DSS
  78. GRB 050721A: Swift-BAT refined analysis
  79. GRB 050721A: Early Swift XRT analysis results
  80. GRB050721A: optical decay
  81. GRB 050721: optical afterglow confirmed
  82. GRB 050709: Refined Spectral and Temporal Properties
  83. GRB050714b: Radio Observation
  84. GRB050712: Radio Observations
  85. GRB050713a: Radio Observation
  86. GRB 050712, Tautenburg optical afterglow observations
  87. Swift-BAT detection of a possible GRB
  88. GRB 050714B: VLT R-band observations
  89. GRB 050717: Additional LCO observations
  90. GRB 050716; J-band observations
  91. GRB 050717: LCO near-IR observations
  92. Swift/UVOT Observations of GRB 050717
  93. GRB 050717: Swift-BAT refined analysis
  94. GRB050717: Swift XRT position
  95. Swift detection of GRB 050717
  96. Swift UVOT Observations of GRB 050716
  97. GRB 050716: Refined XRT analysis.
  98. GRB050716: Refined analysis of the Swift-BAT burst
  99. GRB 050716: Lulin B and R band optical observations
  100. GRB050716, optical observation

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