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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"

28035 results found.

  1. GRB050820B XMM-Newton observation
  2. GRB 050820a: NIR Observations by WIRO
  3. GRB 050820B: Swift XRT position
  4. GRB050820B: Refined analysis of the Swift-BAT burst
  5. GRB050820: refined XRT analysis
  6. GRB 050820 Swift-BAT refined analysis
  7. GRB050819: refined XRT analysis
  8. GRB 050820: Swift detection of a GRB
  9. GRB 050819 Swift-BAT refined analysis
  10. GRB050819: Swift-BAT detection of a weak burst
  11. GRB 050817: Optical observations
  12. GRB050817: Negative Optical Observations
  13. GRB 050814: continued fading
  14. GRB050815: Optical afterglow detection by Swift UVOT
  15. GRB050815: XRT refined analysis
  16. GRB050815: Refined analysis of the Swift-BAT burst
  17. GRB 050815: ROTSE-III Optical Limits
  18. GRB050815: Swift-BAT detection of a burst
  19. GRB050814: Fading red source
  20. GRB050814: P60 Optical Afterglow Candidate
  21. GRB 050813: Non-fading of afterglow candidate
  22. GRB 050814: XRT refined analysis
  23. GRB050814: SWIFT/UVOT observation
  24. GRB050814: Refined analysis of the Swift-BAT burst
  25. GRB 050813: Gemini spectroscopy and redshifts of galaxies B and C
  26. GRB 050814: Swift XRT Afterglow Localization
  27. GRB 050814: Swift detection of a burst
  28. GRB 050813: Magellan detection of a high redshift galaxy cluster
  29. GRB050813, SDSS pre-burst observations
  30. GRB 050813: Swift-BAT refined analysis
  31. GRB 050813: Photometry of object in XRT error circle
  32. GRB050813: SWIFT/UVOT observation
  33. GRB 050813: Swift XRT afterglow localization
  34. Ongoing activity of SGR 1806-20: an intermediate burst 050811
  35. Detection of an intermediate burst from SGR 1806-20 on August 8
  36. GRB050805b: CrAO optical limit
  37. GRB050803, optical observations
  38. Retraction of Swift Trigger 149131 (GRB 050805B)
  39. GRB 050805b: OHP optical limits
  40. GRB 050805b: TAROT optical limits
  41. GRB050805b: MASTER optical observations
  42. Possible GRB 050805B: Swift-BAT trigger 149131 may be a burst
  43. GRB050805a: MASTER optical candidat
  44. GRB050802: TNG optical observations
  45. GRB050803: Radio Observation
  46. GRB 050803: RTT150 optical observations
  47. GRB050801: Radio Observation
  48. GRB050730: Radio Detection
  49. GRB 050803: Keck Observations
  50. GRB 050803: Swift-BAT refined analysis
  51. GRB 050802.422: Fading of the afterglow and detection of the host
  52. GRB 050803: early Swift XRT analysis results
  53. GRB 050803: TAROT optical limits
  54. GCN GRB observation 050713A
  55. GRB050730: FORS1 and UVES/VLT low- and high-resolution spectroscopy
  56. GRB050802 radio non-detection
  57. GRB 050730: OHP optical observations
  58. GRB 050802: early Swift XRT analysis results
  59. GRB 050802: Swift/UVOT observations
  60. GRB 050802: Swift-BAT refined analysis
  61. GRB050801: Optical photometry and decay index
  62. GRB 050802: Swift Gamma-ray Burst
  63. GRB050801: Swift/UVOT Optical and UV detections
  64. GRB 050730: Preliminary Analysis of MIKE Spectrum
  65. GCN 050801: early Swift XRT analysis results
  66. GRB 050801: Swift-BAT refined analysis
  67. GRB 050730: XRT refined analysis
  68. GRB 050730: early TAROT optical observations
  69. GRB 050730, spectra and optical photometry
  70. GRB050730: Refined BAT analysis of the Swift-BAT burst
  71. GRB 050730 XMM-Newton observation
  72. GRB050730: Swift-BAT detection of a weak burst
  73. GRB050713b: Maidanak optical observations
  74. GRB 050724: Secure Host Redshift from Keck
  75. GRB 050724: WHT optical observations
  76. GRB050713: analysis of the XMM-Newton observation
  77. Swift-BAT trigger 147918 is not a real GRB
  78. GRB050724: VLT observations of the variable source
  79. GRB050709: Second Epoch Chandra Observation
  80. GRB050726: Swift-BAT detection of a weak burst
  81. GRB 050724: Optical Variability in Nearby Galaxy
  82. GRB 050724: J-band observations
  83. GRB 050724: GMOS Imaging and Spectroscopy
  84. GRB050724: Radio Observation
  85. GRB 050724: Optical imaging/astrometry
  86. GRB 050724: Swift/UVOT Upper Limit
  87. GRB050724: Refined analysis of the Swift-BAT possible short burst
  88. GRB 050724: possible host galaxy in DSS
  89. GRB 050721A: Swift-BAT refined analysis
  90. GRB 050721A: Early Swift XRT analysis results
  91. GRB050721A: optical decay
  92. GRB 050721: optical afterglow confirmed
  93. GRB 050709: Refined Spectral and Temporal Properties
  94. GRB050714b: Radio Observation
  95. GRB050712: Radio Observations
  96. GRB050713a: Radio Observation
  97. GRB 050712, Tautenburg optical afterglow observations
  98. Swift-BAT detection of a possible GRB
  99. GRB 050714B: VLT R-band observations
  100. GRB 050717: Additional LCO observations

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