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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"

18335 results found.

  1. GCN 050801: early Swift XRT analysis results
  2. GRB 050730: early TAROT optical observations
  3. GRB 050730, spectra and optical photometry
  4. GRB 050730 XMM-Newton observation
  5. GRB050730: Swift-BAT detection of a weak burst
  6. GRB050713: analysis of the XMM-Newton observation
  7. GRB050709: Second Epoch Chandra Observation
  8. GRB 050724: Optical Variability in Nearby Galaxy
  9. GRB 050724: J-band observations
  10. GRB 050724: GMOS Imaging and Spectroscopy
  11. GRB050724: Radio Observation
  12. GRB 050724: Swift/UVOT Upper Limit
  13. GRB 050724: early Swift XRT analysis results
  14. GRB 050724: possible host galaxy in DSS
  15. GRB050721A: optical decay
  16. GRB 050721: optical afterglow confirmed
  17. GRB050714b: Radio Observation
  18. GRB050712: Radio Observations
  19. GRB050713a: Radio Observation
  20. GRB 050712, Tautenburg optical afterglow observations
  21. Swift-BAT detection of a possible GRB
  22. GRB 050714B: VLT R-band observations
  23. GRB 050717: Additional LCO observations
  24. GRB 050716; J-band observations
  25. GRB 050717: LCO near-IR observations
  26. Swift/UVOT Observations of GRB 050717
  27. GRB050717: Swift XRT position
  28. Swift detection of GRB 050717
  29. Swift UVOT Observations of GRB 050716
  30. GRB 050716: Lulin B and R band optical observations
  31. GRB050716, optical observation
  32. GRB050716: Faulkes North Telescope observation
  33. GRB 050714B: refined XRT analysis
  34. GRB 050713b: RTT150 optical observations
  35. GRB 050714B: optical afterglow
  36. GRB 050714, R-band candidate
  37. GRB 050714: Swift XRT afterglow position
  38. GRB 050714, optical observations
  39. GRB 050713A: RAPTOR detection of early optical emission
  40. GRB050713B :Swift/UVOT observations
  41. GRB050712: TNG R-band observations
  42. GRB 050713A: Swift/UVOT observation
  43. GRB050712: Swift UVOT Observation of Afterglow Emission
  44. GRB 050713A XMM-Newton observation
  45. GRB050713B: Faulkes North Telescope observation
  46. GRB050709 : Chandra source optical counterpart
  47. GRB 050712, optical observations
  48. GRB050709: Candidate X-ray Afterglow from Chandra
  49. GRB050713: possible I-band afterglow
  50. GRB050709: Radio Observations
  51. GRB 050709: Swift UVOT and XRT observations
  52. GRB050712: UVOT candidate optical counterpart
  53. GRB 050709: LCO40 Observations
  54. GRB050709: A Possible Short-Hard GRB Localized by HETE
  55. PROMPT Rc Observations of GRB 050709
  56. GRB 050525a: PROMPT VRcIc Detections
  57. GRB 050525a: ARC 3.5-meter Optical and NIR Observations
  58. GRB 050525a: ARC 3.5-Meter SPIcam Field Calibration
  59. GRB 050408: ARC 3.5-meter NIR Observations
  60. Swift UVOT observations of GRB 050701
  61. GRB 050607, radio observations
  62. GRB050525a: HST Observations
  63. CORRECTION: GRB050603 Swift UVOT Afterglow Observations
  64. XRF 050509c: Optical monitoring
  65. XRF050509c: Radio Detection
  66. GRB 050607 optical decay
  67. GRB050607: refined analysis of prompt REM observations
  68. GRB 050607: Optical decay and spectral slope
  69. GRB050607,optical observation
  70. Optical Afterglow of GRB 050607
  71. GRB050607: Swift Detection of a long GRB
  72. GRB050607: prompt REM observations
  73. Limits on a SN in the field of GRB 050509b
  74. GRB050603: Fading Afterglow observed by Swift UVOT
  75. GRB050603, submillimetre observations
  76. GRB050603: Radio Detection
  77. GRB 050603: Swift-BAT refined analysis of a long three-spiked burst
  78. GRB 050603: INTEGRAL shows it is not a short GRB
  79. GRB 050525a, infrared observations
  80. GRB050528, XRT observations
  81. GRB050528: updated Liverpool Telescope limits
  82. GRB050504: Ashra-P2/3 monitor and Ashra-AFT response
  83. Possible GRB050528: no candidate from Liverpool Telescope
  84. GRB050525a: Radio Observations
  85. GRB 050509b: refined XRT/Chandra afterglow position analysis
  86. GRB 050525: RTT150, Optical observations
  87. GRB 050525a: SARA Observations
  88. GRB 050525B: Swift-BAT observations
  89. GRB 050525: MITSuME Optical Observation in VRI
  90. GRB050525A,optical observation
  91. GRB050525: Super-LOTIS observations
  92. GRB050306: optical afterglow not confirmed
  93. GRB 050525: BART optical observation
  94. GRB 050525A: BOOTES simultaneous optical observations
  95. GRB050525: Optical observations
  96. GRB 050525B: INTEGRAL shows it is unrelated to GRB050525A
  97. GRB 050525: TAROT observations of the early afterglow
  98. INTEGRAL detection of GRB 050525
  99. GRB 050525, infrared observations
  100. GRB 050525: observatons of the optical afterglow

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