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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"

26337 results found.

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

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