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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"

19549 results found.

  1. GRB 050803: Keck Observations
  2. GRB 050802.422: Fading of the afterglow and detection of the host
  3. GRB 050803: TAROT optical limits
  4. GRB050802 radio non-detection
  5. GRB 050730: OHP optical observations
  6. GRB050801: Optical photometry and decay index
  7. GRB 050802: XRT position
  8. GRB 050802: Swift Gamma-ray Burst
  9. GCN 050801: early Swift XRT analysis results
  10. GRB 050730: early TAROT optical observations
  11. GRB 050730, spectra and optical photometry
  12. GRB 050730 XMM-Newton observation
  13. GRB050730: Swift-BAT detection of a weak burst
  14. GRB050713: analysis of the XMM-Newton observation
  15. GRB050709: Second Epoch Chandra Observation
  16. GRB 050724: Optical Variability in Nearby Galaxy
  17. GRB 050724: J-band observations
  18. GRB 050724: GMOS Imaging and Spectroscopy
  19. GRB050724: Radio Observation
  20. GRB 050724: Swift/UVOT Upper Limit
  21. GRB 050724: possible host galaxy in DSS
  22. GRB050721A: optical decay
  23. GRB 050721: optical afterglow confirmed
  24. GRB 050709: Refined Spectral and Temporal Properties
  25. GRB050714b: Radio Observation
  26. GRB050712: Radio Observations
  27. GRB050713a: Radio Observation
  28. GRB 050712, Tautenburg optical afterglow observations
  29. Swift-BAT detection of a possible GRB
  30. GRB 050714B: VLT R-band observations
  31. GRB 050717: Additional LCO observations
  32. GRB 050716; J-band observations
  33. GRB 050717: LCO near-IR observations
  34. Swift/UVOT Observations of GRB 050717
  35. GRB 050717: Swift-BAT refined analysis
  36. GRB050712: optical limits
  37. GRB050717: Swift XRT position
  38. Swift detection of GRB 050717
  39. Swift UVOT Observations of GRB 050716
  40. GRB 050716: Lulin B and R band optical observations
  41. GRB050716, optical observation
  42. GRB050716: Faulkes North Telescope observation
  43. GRB 050713b: RTT150 optical observations
  44. GRB 050714B: optical afterglow
  45. GRB 050714, R-band candidate
  46. GRB 050714, optical observations
  47. GRB 050713A: RAPTOR detection of early optical emission
  48. GRB050713B :Swift/UVOT observations
  49. GRB050712: TNG R-band observations
  50. GRB 050713A: Swift/UVOT observation
  51. GRB050712: Swift UVOT Observation of Afterglow Emission
  52. GRB 050713A XMM-Newton observation
  53. GRB050713B: Faulkes North Telescope observation
  54. GRB050709 : Chandra source optical counterpart
  55. GRB 050712, optical observations
  56. GRB050709: Candidate X-ray Afterglow from Chandra
  57. GRB050713: possible I-band afterglow
  58. GRB050709: Radio Observations
  59. GRB050712: UVOT candidate optical counterpart
  60. GRB 050709: LCO40 Observations
  61. PROMPT Rc Observations of GRB 050709
  62. GRB 050525a: PROMPT VRcIc Detections
  63. GRB 050525a: ARC 3.5-meter Optical and NIR Observations
  64. GRB 050525a: ARC 3.5-Meter SPIcam Field Calibration
  65. GRB 050408: ARC 3.5-meter NIR Observations
  66. Swift UVOT observations of GRB 050701
  67. GRB 050607, radio observations
  68. H11603: An X-ray flare from V4641 Sgr, or a possible XRF
  69. GRB 050626 - a long GRB detected with INTEGRAL
  70. GRB050525a: HST Observations
  71. XRF 050509c: Optical monitoring
  72. XRF050509c: Radio Detection
  73. GRB 050607: MDM Observation
  74. GRB 050607 optical decay
  75. GRB050607: refined analysis of prompt REM observations
  76. GRB 050607 : Lulin R-band observation
  77. GRB 050525a, Mid-Infrared Observations
  78. GRB 050607: Optical decay and spectral slope
  79. GRB050607,optical observation
  80. Optical Afterglow of GRB 050607
  81. GRB050607 optical limit by "Pi of the Sky"
  82. GRB050607: Swift Detection of a long GRB
  83. GRB050607: prompt REM observations
  84. Limits on a SN in the field of GRB 050509b
  85. GRB050603, submillimetre observations
  86. GRB 050603: Swift XRT Position
  87. GRB050603: Radio Detection
  88. GRB 050603: Swift-BAT refined analysis of a long three-spiked burst
  89. GRB 050603: INTEGRAL shows it is not a short GRB
  90. Swift/BAT Detection of GRB050603
  91. GRB 050525a, infrared observations
  92. GRB050528: updated Liverpool Telescope limits
  93. Swift-BAT GRB 050528: a soft burst
  94. GRB050504: Ashra-P2/3 monitor and Ashra-AFT response
  95. Possible GRB050528: no candidate from Liverpool Telescope
  96. GRB050525a: Radio Observations
  97. GRB 050509b: refined XRT/Chandra afterglow position analysis
  98. GRB 050525: RTT150, Optical observations
  99. GRB 050525a: SARA Observations
  100. GRB 050525B: Swift-BAT observations

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