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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"

28038 results found.

  1. Swift/UVOT UV Photometry of GRB 050820B
  2. GRB 050822: Swift detection of a long burst
  3. GRB050820a BVRcIc field photometry
  4. GRB050820B XMM-Newton observation
  5. GRB 050820a: NIR Observations by WIRO
  6. GRB 050820B: Swift XRT position
  7. GRB050820B: Refined analysis of the Swift-BAT burst
  8. GRB050820: refined XRT analysis
  9. GRB 050820 Swift-BAT refined analysis
  10. GRB050819: refined XRT analysis
  11. GRB 050820: Swift detection of a GRB
  12. GRB 050819 Swift-BAT refined analysis
  13. GRB050819: Swift-BAT detection of a weak burst
  14. GRB 050817: Optical observations
  15. GRB050817: Negative Optical Observations
  16. GRB 050814: continued fading
  17. GRB050815: Optical afterglow detection by Swift UVOT
  18. GRB050815: XRT refined analysis
  19. GRB050815: Refined analysis of the Swift-BAT burst
  20. GRB 050815: ROTSE-III Optical Limits
  21. GRB050815: Swift-BAT detection of a burst
  22. GRB050814: Fading red source
  23. GRB050814: P60 Optical Afterglow Candidate
  24. GRB 050813: Non-fading of afterglow candidate
  25. GRB 050814: XRT refined analysis
  26. GRB050814: SWIFT/UVOT observation
  27. GRB050814: Refined analysis of the Swift-BAT burst
  28. GRB 050813: Gemini spectroscopy and redshifts of galaxies B and C
  29. GRB 050814: Swift XRT Afterglow Localization
  30. GRB 050814: Swift detection of a burst
  31. GRB 050813: Magellan detection of a high redshift galaxy cluster
  32. GRB050813, SDSS pre-burst observations
  33. GRB 050813: Swift-BAT refined analysis
  34. GRB 050813: Photometry of object in XRT error circle
  35. GRB050813: SWIFT/UVOT observation
  36. GRB 050813: Swift XRT afterglow localization
  37. Ongoing activity of SGR 1806-20: an intermediate burst 050811
  38. Detection of an intermediate burst from SGR 1806-20 on August 8
  39. GRB050805b: CrAO optical limit
  40. GRB050803, optical observations
  41. Retraction of Swift Trigger 149131 (GRB 050805B)
  42. GRB 050805b: OHP optical limits
  43. GRB 050805b: TAROT optical limits
  44. GRB050805b: MASTER optical observations
  45. Possible GRB 050805B: Swift-BAT trigger 149131 may be a burst
  46. GRB050805a: MASTER optical candidat
  47. GRB050802: TNG optical observations
  48. GRB050803: Radio Observation
  49. GRB 050803: RTT150 optical observations
  50. GRB050801: Radio Observation
  51. GRB050730: Radio Detection
  52. GRB 050803: Keck Observations
  53. GRB 050803: Swift-BAT refined analysis
  54. GRB 050802.422: Fading of the afterglow and detection of the host
  55. GRB 050803: early Swift XRT analysis results
  56. GRB 050803: TAROT optical limits
  57. GCN GRB observation 050713A
  58. GRB050730: FORS1 and UVES/VLT low- and high-resolution spectroscopy
  59. GRB050802 radio non-detection
  60. GRB 050730: OHP optical observations
  61. GRB 050802: early Swift XRT analysis results
  62. GRB 050802: Swift/UVOT observations
  63. GRB 050802: Swift-BAT refined analysis
  64. GRB050801: Optical photometry and decay index
  65. GRB 050802: Swift Gamma-ray Burst
  66. GRB050801: Swift/UVOT Optical and UV detections
  67. GRB 050730: Preliminary Analysis of MIKE Spectrum
  68. GCN 050801: early Swift XRT analysis results
  69. GRB 050801: Swift-BAT refined analysis
  70. GRB 050730: XRT refined analysis
  71. GRB 050730: early TAROT optical observations
  72. GRB 050730, spectra and optical photometry
  73. GRB050730: Refined BAT analysis of the Swift-BAT burst
  74. GRB 050730 XMM-Newton observation
  75. GRB050730: Swift-BAT detection of a weak burst
  76. GRB050713b: Maidanak optical observations
  77. GRB 050724: Secure Host Redshift from Keck
  78. GRB 050724: WHT optical observations
  79. GRB050713: analysis of the XMM-Newton observation
  80. Swift-BAT trigger 147918 is not a real GRB
  81. GRB050724: VLT observations of the variable source
  82. GRB050709: Second Epoch Chandra Observation
  83. GRB050726: Swift-BAT detection of a weak burst
  84. GRB 050724: Optical Variability in Nearby Galaxy
  85. GRB 050724: J-band observations
  86. GRB 050724: GMOS Imaging and Spectroscopy
  87. GRB050724: Radio Observation
  88. GRB 050724: Optical imaging/astrometry
  89. GRB 050724: Swift/UVOT Upper Limit
  90. GRB050724: Refined analysis of the Swift-BAT possible short burst
  91. GRB 050724: possible host galaxy in DSS
  92. GRB 050721A: Swift-BAT refined analysis
  93. GRB 050721A: Early Swift XRT analysis results
  94. GRB050721A: optical decay
  95. GRB 050721: optical afterglow confirmed
  96. GRB 050709: Refined Spectral and Temporal Properties
  97. GRB050714b: Radio Observation
  98. GRB050712: Radio Observations
  99. GRB050713a: Radio Observation
  100. GRB 050712, Tautenburg optical afterglow observations

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