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

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