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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. Optical Afterglow of GRB 050607
  2. GRB050607 optical limit by "Pi of the Sky"
  3. GRB050607: Swift Detection of a long GRB
  4. GRB050607: P60 Observations
  5. GRB050607: prompt REM observations
  6. GRB 050603: prediction of t_break
  7. Limits on a SN in the field of GRB 050509b
  8. GRB 050603: Redshift
  9. GRB 050603 - XRT data analysis of the first day
  10. Konus-Wind observation of GRB 050603
  11. GRB 050603: Analysis of UVOT data
  12. GRB050603: Fading Afterglow observed by Swift UVOT
  13. GRB050603, submillimetre observations
  14. GRB 050603: Swift XRT Position
  15. GRB050603: Radio Detection
  16. GRB 050603: Swift-BAT refined analysis of a long three-spiked burst
  17. GRB 050603: Afterglow Identification from LCO
  18. GRB 050603: INTEGRAL shows it is not a short GRB
  19. Swift/BAT Detection of GRB050603
  20. GRB 050408: jet break in the XRT light curve
  21. GRB 050525a, infrared observations
  22. GRB 050525a, SMARTS optical/IR afterglow observations
  23. GRB050528, XRT observations
  24. Correction to GCN Circ 3502 on GRB 050528
  25. GRB050528: updated Liverpool Telescope limits
  26. Swift-BAT GRB 050528: a soft burst
  27. Update on Swift-BAT GRB 050528 (Trigger 130679)
  28. GRB050528: BOOTES optical candidate (retraction)
  29. GRB050504: Ashra-P2/3 monitor and Ashra-AFT response
  30. GRB050528: BOOTES optical candidate
  31. Possible GRB050528: no candidate from Liverpool Telescope
  32. Swift-BAT detection of possible GRB 050528
  33. GRB050525a: Radio Observations
  34. GRB 050509b: refined XRT/Chandra afterglow position analysis
  35. GRB 050525: RTT150, Optical observations
  36. GRB050525a: optical upper limits
  37. GRB 050525a: SARA Observations
  38. GRB 050525B: Swift-BAT observations
  39. GRB 050525: MITSuME Optical Observation in VRI
  40. GRB 050525a: MDM Observations
  41. GRB050525A,optical observation
  42. GRB 050525 : Lulin optical afterglow observations
  43. GRB050525: Super-LOTIS observations
  44. GRB 050525, spectral lag pseudo-redshift
  45. GRB 050525a: Gemini/GMOS Spectra
  46. GRB050306: optical afterglow not confirmed
  47. GRB 050525: BART optical observation
  48. GRB 050525A: BOOTES simultaneous optical observations
  49. GRB 050525A: Swift-BAT refined analysis
  50. GRB050525: Optical observations
  51. GRB 050525B: INTEGRAL shows it is unrelated to GRB050525A
  52. Subject : GRB 050525: pseudo-redshift
  53. Swift/UVOT UV and optical detections of GRB 050525
  54. Konus-Wind observation of GRB 050525
  55. GRB 050525: TAROT observations of the early afterglow
  56. INTEGRAL detection of GRB 050525
  57. GRB 050525, infrared observations
  58. GRB 050525: Optical observation
  59. GRB 050525: observatons of the optical afterglow
  60. GRB050525: ROTSE-III Refined Analysis
  61. GRB 050525 - Very Bright, Not Short
  62. GRB 050525: Swift Detection of a Bright, Possibly Short Burst
  63. GRB 050525A: ROTSE-III Detection of Possible Counterpart
  64. XRF050522: NIR observations of XRT candidate
  65. XRF 050522: Swift XRT refined analysis
  66. XRF050522: Radio Observations
  67. Swift/UVOT observation of XRF 050522
  68. GRB 050509A: Further I-band imaging
  69. GRB050522,optical observation
  70. GRB050520,optical observation
  71. XRF 050522: Continued NIR P200 Monitoring
  72. RBO Observations of GRB050522
  73. GRB050509b: optical observations
  74. Recent GRB BVRcIc field photometry
  75. GRB050520: Radio Observations
  76. XRF 050522: Swift XRT observation
  77. XRF050522, BVRcIc field photometry
  78. XRF 050522 : Lulin observations
  79. XRF050522: Optical Observations
  80. XRF050522: Near-infrared Observations
  81. XRF 050522: KAIT observations
  82. XRF 050522 detected with INTEGRAL
  83. GRB 050520: VLT/ULTRACAM observations
  84. Swift UVOT Observations of GRB 050520
  85. GRB 050520: Swift XRT refined analysis
  86. XRF050509C: Chandra Afterglow Detection
  87. XRF 050509c: Swift XRT Upper Limit
  88. XRF050509c: Radio Observations
  89. RBO Observations of GRB050520
  90. GRB 050520: P200 Observations
  91. GRB050520: Liverpool Telescope follow-up
  92. RBO Observations of GRB050520
  93. GRB 050520: TAROT optical limit
  94. GRB 050520: Swift XRT position
  95. GRB 050520: VLT/ULTRACAM observations
  96. GRB 050520: OSN optical observations
  97. GRB 050520: BART optical limit
  98. GRB 050520 - A long GRB detected with INTEGRAL
  99. No Swift-BAT Lightcurves in real-time for next 3 weeks
  100. Swift-BAT trigger 122203 is not a real GRB

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