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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"

26336 results found.

  1. GRB050820a BVRcIc field photometry
  2. GRB050820B XMM-Newton observation
  3. GRB 050820a: NIR Observations by WIRO
  4. GRB 050820B: Swift XRT position
  5. GRB050820B: Refined analysis of the Swift-BAT burst
  6. GRB050820: refined XRT analysis
  7. GRB 050820 Swift-BAT refined analysis
  8. GRB050819: refined XRT analysis
  9. GRB 050820: Swift detection of a GRB
  10. GRB 050819 Swift-BAT refined analysis
  11. GRB050819: Swift-BAT detection of a weak burst
  12. GRB 050817: Optical observations
  13. GRB050817: Negative Optical Observations
  14. GRB 050814: continued fading
  15. GRB050815: Optical afterglow detection by Swift UVOT
  16. GRB050815: XRT refined analysis
  17. GRB050815: Refined analysis of the Swift-BAT burst
  18. GRB 050815: ROTSE-III Optical Limits
  19. GRB050815: Swift-BAT detection of a burst
  20. GRB050814: Fading red source
  21. GRB050814: P60 Optical Afterglow Candidate
  22. GRB 050813: Non-fading of afterglow candidate
  23. GRB 050814: XRT refined analysis
  24. GRB050814: SWIFT/UVOT observation
  25. GRB050814: Refined analysis of the Swift-BAT burst
  26. GRB 050813: Gemini spectroscopy and redshifts of galaxies B and C
  27. GRB 050814: Swift XRT Afterglow Localization
  28. GRB 050814: Swift detection of a burst
  29. GRB 050813: Magellan detection of a high redshift galaxy cluster
  30. GRB050813, SDSS pre-burst observations
  31. GRB 050813: Swift-BAT refined analysis
  32. GRB 050813: Photometry of object in XRT error circle
  33. GRB050813: SWIFT/UVOT observation
  34. GRB 050813: Swift XRT afterglow localization
  35. Ongoing activity of SGR 1806-20: an intermediate burst 050811
  36. Detection of an intermediate burst from SGR 1806-20 on August 8
  37. GRB050805b: CrAO optical limit
  38. GRB050803, optical observations
  39. Retraction of Swift Trigger 149131 (GRB 050805B)
  40. GRB 050805b: OHP optical limits
  41. GRB 050805b: TAROT optical limits
  42. GRB050805b: MASTER optical observations
  43. Possible GRB 050805B: Swift-BAT trigger 149131 may be a burst
  44. GRB050805a: MASTER optical candidat
  45. GRB050802: TNG optical observations
  46. GRB050803: Radio Observation
  47. GRB 050803: RTT150 optical observations
  48. GRB050801: Radio Observation
  49. GRB050730: Radio Detection
  50. GRB 050803: Keck Observations
  51. GRB 050803: Swift-BAT refined analysis
  52. GRB 050802.422: Fading of the afterglow and detection of the host
  53. GRB 050803: early Swift XRT analysis results
  54. GRB 050803: TAROT optical limits
  55. GCN GRB observation 050713A
  56. GRB050730: FORS1 and UVES/VLT low- and high-resolution spectroscopy
  57. GRB050802 radio non-detection
  58. GRB 050730: OHP optical observations
  59. GRB 050802: early Swift XRT analysis results
  60. GRB 050802: Swift/UVOT observations
  61. GRB 050802: Swift-BAT refined analysis
  62. GRB050801: Optical photometry and decay index
  63. GRB 050802: Swift Gamma-ray Burst
  64. GRB050801: Swift/UVOT Optical and UV detections
  65. GRB 050730: Preliminary Analysis of MIKE Spectrum
  66. GCN 050801: early Swift XRT analysis results
  67. GRB 050801: Swift-BAT refined analysis
  68. GRB 050730: XRT refined analysis
  69. GRB 050730: early TAROT optical observations
  70. GRB 050730, spectra and optical photometry
  71. GRB050730: Refined BAT analysis of the Swift-BAT burst
  72. GRB 050730 XMM-Newton observation
  73. GRB050730: Swift-BAT detection of a weak burst
  74. GRB050713b: Maidanak optical observations
  75. GRB 050724: Secure Host Redshift from Keck
  76. GRB 050724: WHT optical observations
  77. GRB050713: analysis of the XMM-Newton observation
  78. Swift-BAT trigger 147918 is not a real GRB
  79. GRB050724: VLT observations of the variable source
  80. GRB050709: Second Epoch Chandra Observation
  81. GRB050726: Swift-BAT detection of a weak burst
  82. GRB 050724: Optical Variability in Nearby Galaxy
  83. GRB 050724: J-band observations
  84. GRB 050724: GMOS Imaging and Spectroscopy
  85. GRB050724: Radio Observation
  86. GRB 050724: Optical imaging/astrometry
  87. GRB 050724: Swift/UVOT Upper Limit
  88. GRB050724: Refined analysis of the Swift-BAT possible short burst
  89. GRB 050724: possible host galaxy in DSS
  90. GRB 050721A: Swift-BAT refined analysis
  91. GRB 050721A: Early Swift XRT analysis results
  92. GRB050721A: optical decay
  93. GRB 050721: optical afterglow confirmed
  94. GRB 050709: Refined Spectral and Temporal Properties
  95. GRB050714b: Radio Observation
  96. GRB050712: Radio Observations
  97. GRB050713a: Radio Observation
  98. GRB 050712, Tautenburg optical afterglow observations
  99. Swift-BAT detection of a possible GRB
  100. GRB 050714B: VLT R-band observations

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