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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. Konus-Wind observation of GRB 050525
  2. GRB 050525: TAROT observations of the early afterglow
  3. INTEGRAL detection of GRB 050525
  4. GRB 050525, infrared observations
  5. GRB 050525: Optical observation
  6. GRB 050525: observatons of the optical afterglow
  7. GRB050525: ROTSE-III Refined Analysis
  8. GRB 050525 - Very Bright, Not Short
  9. GRB 050525: Swift Detection of a Bright, Possibly Short Burst
  10. GRB 050525A: ROTSE-III Detection of Possible Counterpart
  11. XRF050522: NIR observations of XRT candidate
  12. XRF 050522: Swift XRT refined analysis
  13. XRF050522: Radio Observations
  14. Swift/UVOT observation of XRF 050522
  15. GRB 050509A: Further I-band imaging
  16. GRB050522,optical observation
  17. GRB050520,optical observation
  18. XRF 050522: Continued NIR P200 Monitoring
  19. RBO Observations of GRB050522
  20. GRB050509b: optical observations
  21. Recent GRB BVRcIc field photometry
  22. GRB050520: Radio Observations
  23. XRF 050522: Swift XRT observation
  24. XRF050522, BVRcIc field photometry
  25. XRF 050522 : Lulin observations
  26. XRF050522: Optical Observations
  27. XRF050522: Near-infrared Observations
  28. XRF 050522: KAIT observations
  29. XRF 050522 detected with INTEGRAL
  30. GRB 050520: VLT/ULTRACAM observations
  31. Swift UVOT Observations of GRB 050520
  32. GRB 050520: Swift XRT refined analysis
  33. XRF050509C: Chandra Afterglow Detection
  34. XRF 050509c: Swift XRT Upper Limit
  35. XRF050509c: Radio Observations
  36. RBO Observations of GRB050520
  37. GRB 050520: P200 Observations
  38. GRB050520: Liverpool Telescope follow-up
  39. RBO Observations of GRB050520
  40. GRB 050520: TAROT optical limit
  41. GRB 050520: Swift XRT position
  42. GRB 050520: VLT/ULTRACAM observations
  43. GRB 050520: OSN optical observations
  44. GRB 050520: BART optical limit
  45. GRB 050520 - A long GRB detected with INTEGRAL
  46. No Swift-BAT Lightcurves in real-time for next 3 weeks
  47. Swift-BAT trigger 122203 is not a real GRB
  48. XRF 050509C: REM NIR and Optical refined analysis
  49. GRB 050504: Swift XRT afterglow candidate has faded
  50. XRF 050509c optical afterglow
  51. GRB 050509B and short GRB-SN association? (corrected)
  52. GRB 050509B and short GRB-SN association?
  53. GRB 050509B: Subaru Optical Observations
  54. GRB050502b: Early Observation
  55. GRB050509b, Bok telescope B-band imaging
  56. Refined Chandra analysis of GRB 050509b
  57. GRB050509b, SDSS pre-burst observations
  58. GRB 050509b: Keck/Chandra Cross-Correlation
  59. GRB 050509b: Keck/Chandra Cross-Correlation
  60. Chandra observation of GRB 050509b
  61. GRB 050509b: RAPTOR deep, early limits.
  62. GRB050509B: Optical/Infared observations
  63. GRB 050509b: Swift/UVOT follow-up measurements
  64. GRB 050509b Milagro GeV/TeV Observations
  65. GRB050509B: Optical observations at the Very Large Telescope
  66. GRB 050509b: No Optical Variability in XRT Error Circle
  67. GRB050416: Afterglow detection at 188 nm with Swift UVOT
  68. GRB 050509a: Swift-BAT refined analysis
  69. GRB 050509c: ROTSE-III Optical Limits
  70. GRB 050509B: WSRT Radio Observations
  71. GRB050509c: REM NIR and Optical observations (errata corrige to GCN 3400)
  72. GRB 050505, early TAROT observation
  73. GRB050509c (=H3751): An X-Ray Flash Localized By HETE
  74. GRB 050509b: Further Analysis of Keck LRIS Images
  75. GRB050509c: REM NIR and Optical observations
  76. GRB 050509b: Physical Properties of the Candidate Host galaxy
  77. GRB 050505: SARA Observations
  78. Swift UVOT Follow-up Observations of GRB 050509B
  79. GRB 050509B, Optical Observations
  80. GRB 050509B: Swift/XRT refined analysis
  81. GRB050509a: Swift UVOT observations
  82. GRB 050509b: Optical observations
  83. GRB 050509b: Precision Astrometry
  84. GRB 050509b: Possible Optical Counterpart
  85. Keck/DEIMOS Spectrum of Possible Host Galaxy for GRB050509b
  86. GRB 050509A: Optical observations
  87. GRB 050509b: Optical Counterpart Candidate
  88. GRB050509b: Radio Observations
  89. GRB 050509b: PAIRITEL and WIYN Observations
  90. GRB 050509b: Swift-BAT refined analysis of the short hard burst
  91. GRB 050509b: optical observations
  92. GRB 050509b: Swift XRT Position
  93. GRB 050509B: ROTSE-III Optical Limits
  94. Swift Detection of GRB050509b: A short duration burst
  95. GRB 050509a: Swift XRT Position
  96. Swift Detection of the Burst GRB050509
  97. Swift-BAT detection of GRB 050507
  98. GRB 050505: Keck I-band Magnitude
  99. GRB 050505: early time observations
  100. GRB 050505 - Faulkes Telescope North observations

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