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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"

26500 results found.

  1. Swift-BAT detection of a possible GRB
  2. GRB 050714B: VLT R-band observations
  3. GRB 050717: Additional LCO observations
  4. GRB 050716; J-band observations
  5. GRB 050717: LCO near-IR observations
  6. Swift/UVOT Observations of GRB 050717
  7. GRB 050717: Swift-BAT refined analysis
  8. GRB 050717: Refined XRT analysis.
  9. GRB050717: Swift XRT position
  10. Swift detection of GRB 050717
  11. Swift UVOT Observations of GRB 050716
  12. GRB 050716: Refined XRT analysis.
  13. GRB050716: Refined analysis of the Swift-BAT burst
  14. GRB 050716: Lulin B and R band optical observations
  15. GRB050716, optical observation
  16. GRB050716: Faulkes North Telescope observation
  17. GRB050715: Refined analysis of the Swift-BAT burst
  18. GRB 050715: Swift-BAT detection
  19. GRB 050714B: refined XRT analysis
  20. GRB 050713b: RTT150 optical observations
  21. GRB050714B: Refined analysis of the Swift-BAT burst
  22. GRB 050714B: optical afterglow
  23. GRB 050714, R-band candidate
  24. GRB 050714, optical observations
  25. GRB 050713A: XRT refined analysis
  26. GRB 050713A: RAPTOR detection of early optical emission
  27. GRB050713B :Swift/UVOT observations
  28. GRB050713b: XRT refined analysis
  29. GRB050712: TNG R-band observations
  30. GRB 050713B: Swift-BAT Refined Analysis
  31. GRB 050713A: Swift/UVOT observation
  32. GRB 050713A : Swift-BAT Refined Analysis
  33. GRB050712: Swift UVOT Observation of Afterglow Emission
  34. GRB 050713A XMM-Newton observation
  35. GRB050713B: Faulkes North Telescope observation
  36. GRB 050713B
  37. GRB050709 : Chandra source optical counterpart
  38. GRB050713: Liverpool Telescope prompt observations
  39. GRB 050712, optical observations
  40. GRB050709: Candidate X-ray Afterglow from Chandra
  41. GRB 050713, R-band observations at NOT
  42. GRB050713: possible I-band afterglow
  43. GRB050709: Radio Observations
  44. GRB 050709: Swift UVOT and XRT observations
  45. GRB 050712: Swift-BAT Refined Analysis
  46. GRB050712: UVOT candidate optical counterpart
  47. GRB 050709: LCO40 Observations
  48. GRB050709, optical observations
  49. GRB050709: A Possible Short-Hard GRB Localized by HETE
  50. PROMPT Rc Observations of GRB 050709
  51. GRB 050525a: PROMPT VRcIc Detections
  52. GRB 050525a: ARC 3.5-meter Optical and NIR Observations
  53. GRB 050525a: ARC 3.5-Meter SPIcam Field Calibration
  54. GRB 050626: Swift XRT observations
  55. GRB 050701
  56. GRB 050701, optical observations
  57. GRB 050408: ARC 3.5-meter NIR Observations
  58. GRB 050701: Refined XRT analysis
  59. Swift UVOT observations of GRB 050701
  60. GRB 050607, radio observations
  61. H11603: An X-ray flare from V4641 Sgr, or a possible XRF
  62. GRB 050626 - a long GRB detected with INTEGRAL
  63. GRB050525a: HST Observations
  64. H3800 and H3801 on 2005 June 11: two bursts from SGR1806-20 localized by HETE
  65. XRF 050509c: Optical monitoring
  66. XRF050509c: Radio Detection
  67. GRB 050416(a): Host Galaxy Redshift Determination
  68. GRB 050607 optical decay
  69. GRB050607: refined analysis of prompt REM observations
  70. GRB 050607: PROMPT VRcIc Observations
  71. GRB 050525a, Mid-Infrared Observations
  72. GRB 050607: Optical decay and spectral slope
  73. GRB 050607: MDM Observations
  74. GRB050607,optical observation
  75. GRB 050607 - XRT refined data analysis
  76. Optical Afterglow of GRB 050607
  77. GRB050607: Swift Detection of a long GRB
  78. GRB050607: prompt REM observations
  79. Limits on a SN in the field of GRB 050509b
  80. GRB 050603: Redshift
  81. GRB050603, submillimetre observations
  82. GRB 050603: Swift XRT Position
  83. GRB050603: Radio Detection
  84. GRB 050603: Swift-BAT refined analysis of a long three-spiked burst
  85. GRB 050603: INTEGRAL shows it is not a short GRB
  86. GRB 050525a, infrared observations
  87. GRB050528, XRT observations
  88. GRB050528: updated Liverpool Telescope limits
  89. GRB050504: Ashra-P2/3 monitor and Ashra-AFT response
  90. Possible GRB050528: no candidate from Liverpool Telescope
  91. GRB050525a: Radio Observations
  92. GRB 050509b: refined XRT/Chandra afterglow position analysis
  93. GRB 050525: RTT150, Optical observations
  94. GRB 050525a: SARA Observations
  95. GRB 050525B: Swift-BAT observations
  96. GRB 050525: MITSuME Optical Observation in VRI
  97. GRB050525A,optical observation
  98. GRB050525: Super-LOTIS observations
  99. GRB 050525, spectral lag pseudo-redshift
  100. GRB050306: optical afterglow not confirmed

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