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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"

20351 results found.

  1. GRB 050817: Optical observations
  2. GRB050817: Swift-BAT Detection of a burst
  3. GRB 050814: continued fading
  4. GRB050815: Refined analysis of the Swift-BAT burst
  5. GRB 050815: ROTSE-III Optical Limits
  6. GRB050815: Swift-BAT detection of a burst
  7. GRB050814: Fading red source
  8. GRB050814: P60 Optical Afterglow Candidate
  9. GRB 050813: Non-fading of afterglow candidate
  10. GRB 050814: XRT refined analysis
  11. GRB050814: SWIFT/UVOT observation
  12. GRB 050814: Swift XRT Afterglow Localization
  13. GRB 050814: Swift detection of a burst
  14. GRB 050813: Magellan detection of a high redshift galaxy cluster
  15. GRB050813, SDSS pre-burst observations
  16. GRB050813: SWIFT/UVOT observation
  17. GRB 050813: Swift XRT afterglow localization
  18. GRB050803: CrAO optical observations, no OT candidate
  19. GRB050805b: CrAO optical limit
  20. GRB050803, optical observations
  21. Retraction of Swift Trigger 149131 (GRB 050805B)
  22. GRB 050805b: OHP optical limits
  23. GRB 050805b: TAROT optical limits
  24. Possible GRB 050805B: Swift-BAT trigger 149131 may be a burst
  25. GRB050802: TNG optical observations
  26. GRB050803: Radio Observation
  27. GRB 050803: RTT150 optical observations
  28. GRB050801: Radio Observation
  29. GRB050730: Radio Detection
  30. GRB 050803: Keck Observations
  31. GRB 050802.422: Fading of the afterglow and detection of the host
  32. GRB 050803: TAROT optical limits
  33. GRB050803: Swift-BAT detection of a very long burst
  34. GRB050730: FORS1 and UVES/VLT low- and high-resolution spectroscopy
  35. GRB 050802: Swift/UVOT optical and UV detections
  36. GRB050802 radio non-detection
  37. GRB 050730: OHP optical observations
  38. GRB050801: Optical photometry and decay index
  39. GRB 050802: Swift Gamma-ray Burst
  40. GCN 050801: early Swift XRT analysis results
  41. GRB 050730, corrected photometry and break?
  42. GRB 050730: early TAROT optical observations
  43. GRB 050730, spectra and optical photometry
  44. GRB 050730 XMM-Newton observation
  45. GRB 050730: Redshift Measurement based on Magellan/MIKE Observations
  46. GRB050730: Swift-BAT detection of a weak burst
  47. GRB 050713A: Swift XRT extended light curve
  48. GRB 050724: WHT optical observations
  49. GRB050713: analysis of the XMM-Newton observation
  50. GRB050709: Second Epoch Chandra Observation
  51. GRB050709: Second Epoch Chandra Observation
  52. GRB 050724: Optical Variability in Nearby Galaxy
  53. GRB 050724: J-band observations
  54. GRB 050724: GMOS Imaging and Spectroscopy
  55. GRB050724: Radio Observation
  56. GRB 050724: Swift/UVOT Upper Limit
  57. GRB 050724: possible host galaxy in DSS
  58. GRB050721A: optical decay
  59. GRB 050721: optical afterglow confirmed
  60. GRB050714b: Radio Observation
  61. GRB050712: Radio Observations
  62. GRB050713a: Radio Observation
  63. GRB 050712, Tautenburg optical afterglow observations
  64. Swift-BAT detection of a possible GRB
  65. GRB 050714B: VLT R-band observations
  66. GRB 050717: Additional LCO observations
  67. GRB 050716; J-band observations
  68. GRB 050717: LCO near-IR observations
  69. Swift/UVOT Observations of GRB 050717
  70. GRB050717: Swift XRT position
  71. Swift detection of GRB 050717
  72. Swift UVOT Observations of GRB 050716
  73. GRB 050716: Lulin B and R band optical observations
  74. GRB050716, optical observation
  75. GRB050716: Faulkes North Telescope observation
  76. Swift/BAT detection of GRB 050716
  77. Konus-Wind observation of GRB 050713A
  78. GRB 050713b: RTT150 optical observations
  79. GRB 050714B: optical afterglow
  80. GRB 050714, R-band candidate
  81. GRB 050714, optical observations
  82. GRB 050713A: RAPTOR detection of early optical emission
  83. GRB050713B :Swift/UVOT observations
  84. GRB050712: TNG R-band observations
  85. GRB 050713A: Swift/UVOT observation
  86. GRB050712: Swift UVOT Observation of Afterglow Emission
  87. GRB 050713A XMM-Newton observation
  88. GRB050713B: Faulkes North Telescope observation
  89. RBO RI observations of GRB 050713A
  90. GRB050709 : Chandra source optical counterpart
  91. GRB050713: Liverpool Telescope prompt observations
  92. GRB 050712, optical observations
  93. GRB050709: Candidate X-ray Afterglow from Chandra
  94. GRB050713: possible I-band afterglow
  95. GRB 050713A: ROTSE-III Optical Limits
  96. GRB050709: Radio Observations
  97. GRB050712: UVOT candidate optical counterpart
  98. GRB 050712: Swift detection of a weak burst
  99. GRB 050709: LCO40 Observations
  100. PROMPT Rc Observations of GRB 050709

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