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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').
  1. GRB 050709: Swift UVOT and XRT observations
  2. GRB 050712: Swift-BAT Refined Analysis
  3. GRB050712: UVOT candidate optical counterpart
  4. GRB 050712: Swift XRT afterglow position
  5. GRB 050712: Swift detection of a weak burst
  6. GRB 050709: LCO40 Observations
  7. GRB050709, optical observations
  8. GRB050709: A Possible Short-Hard GRB Localized by HETE
  9. PROMPT Rc Observations of GRB 050709
  10. GRB 050525a: PROMPT VRcIc Detections
  11. GRB 050525a: ARC 3.5-meter Optical and NIR Observations
  12. GRB 050525a: ARC 3.5-Meter SPIcam Field Calibration
  13. GRB 050626 optical observations
  14. GRB 050626: Swift XRT observations
  15. GRB 050701
  16. GRB 050701, optical observations
  17. GRB 050408: ARC 3.5-meter NIR Observations
  18. GRB 050701: Refined XRT analysis
  19. Swift UVOT observations of GRB 050701
  20. GRB050701: Swift-BAT Refined analysis
  21. GRB 050701: Swift XRT afterglow position
  22. Swift trigger 143708 is really GRB 050701
  23. GRB 050607, radio observations
  24. H11603: An X-ray flare from V4641 Sgr, or a possible XRF
  25. GRB 050626 - Correction to GCN 3552
  26. GRB 050626 - a long GRB detected with INTEGRAL
  27. GRB 050525A: Swift Late-Time Decay Rate
  28. GRB050525a: HST Observations
  29. CORRECTION: GRB050603 Swift UVOT Afterglow Observations
  30. H3804: A Possible New XRB Detected by HETE
  31. H3800 and H3801 on 2005 June 11: two bursts from SGR1806-20 localized by HETE
  32. XRF 050509c: Optical monitoring
  33. Konus-Wind observation of an intermediate burst from SGR 1806-20
  34. IBAS Alert #2512 is NOT a GRB
  35. XRF050509c: Radio Detection
  36. GRB 050416(a): Host Galaxy Redshift Determination
  37. GRB 050607: MDM Observation
  38. GRB 050607 optical decay
  39. GRB 050607: RTT150 optical observations
  40. GRB050607: refined analysis of prompt REM observations
  41. Swift/UVOT observations of GRB050607
  42. GRB 050607 : Lulin R-band observation
  43. GRB 050607: PROMPT VRcIc Observations
  44. GRB 050607: RAPTOR-S Early Optical Limits
  45. GRB050607: KAIT optical limits
  46. GRB 050525a, Mid-Infrared Observations
  47. GRB 050607: Optical decay and spectral slope
  48. GRB 050607: MDM Observations
  49. GRB050607,optical observation
  50. GRB 050607 - XRT refined data analysis
  51. Optical Afterglow of GRB 050607
  52. GRB050607 optical limit by "Pi of the Sky"
  53. GRB050607: Swift Detection of a long GRB
  54. GRB050607: P60 Observations
  55. GRB050607: prompt REM observations
  56. GRB 050603: prediction of t_break
  57. Limits on a SN in the field of GRB 050509b
  58. GRB 050603: Redshift
  59. GRB 050603 - XRT data analysis of the first day
  60. Konus-Wind observation of GRB 050603
  61. GRB 050603: Analysis of UVOT data
  62. GRB050603: Fading Afterglow observed by Swift UVOT
  63. GRB050603, submillimetre observations
  64. GRB 050603: Swift XRT Position
  65. GRB050603: Radio Detection
  66. GRB 050603: Swift-BAT refined analysis of a long three-spiked burst
  67. GRB 050603: Afterglow Identification from LCO
  68. GRB 050603: INTEGRAL shows it is not a short GRB
  69. Swift/BAT Detection of GRB050603
  70. GRB 050408: jet break in the XRT light curve
  71. GRB 050525a, infrared observations
  72. GRB 050525a, SMARTS optical/IR afterglow observations
  73. GRB050528, XRT observations
  74. Correction to GCN Circ 3502 on GRB 050528
  75. GRB050528: updated Liverpool Telescope limits
  76. Swift-BAT GRB 050528: a soft burst
  77. Update on Swift-BAT GRB 050528 (Trigger 130679)
  78. GRB050528: BOOTES optical candidate (retraction)
  79. GRB050504: Ashra-P2/3 monitor and Ashra-AFT response
  80. GRB050528: BOOTES optical candidate
  81. Possible GRB050528: no candidate from Liverpool Telescope
  82. Swift-BAT detection of possible GRB 050528
  83. GRB050525a: Radio Observations
  84. GRB 050509b: refined XRT/Chandra afterglow position analysis
  85. GRB 050525: RTT150, Optical observations
  86. GRB050525a: optical upper limits
  87. GRB 050525a: SARA Observations
  88. GRB 050525B: Swift-BAT observations
  89. GRB 050525: MITSuME Optical Observation in VRI
  90. GRB 050525a: MDM Observations
  91. GRB050525A,optical observation
  92. GRB 050525 : Lulin optical afterglow observations
  93. GRB050525: Super-LOTIS observations
  94. GRB 050525, spectral lag pseudo-redshift
  95. GRB 050525a: Gemini/GMOS Spectra
  96. GRB050306: optical afterglow not confirmed
  97. GRB 050525: BART optical observation
  98. GRB 050525A: BOOTES simultaneous optical observations
  99. GRB 050525A: Swift-BAT refined analysis
  100. GRB050525: Optical observations

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