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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 050525B: INTEGRAL shows it is unrelated to GRB050525A
  2. Subject : GRB 050525: pseudo-redshift
  3. Swift/UVOT UV and optical detections of GRB 050525
  4. Konus-Wind observation of GRB 050525
  5. GRB 050525: TAROT observations of the early afterglow
  6. INTEGRAL detection of GRB 050525
  7. GRB 050525, infrared observations
  8. GRB 050525: Optical observation
  9. GRB 050525: observatons of the optical afterglow
  10. GRB050525: ROTSE-III Refined Analysis
  11. GRB 050525 - Very Bright, Not Short
  12. GRB 050525: Swift Detection of a Bright, Possibly Short Burst
  13. GRB 050525A: ROTSE-III Detection of Possible Counterpart
  14. XRF050522: NIR observations of XRT candidate
  15. XRF 050522: Swift XRT refined analysis
  16. XRF050522: Radio Observations
  17. Swift/UVOT observation of XRF 050522
  18. GRB 050509A: Further I-band imaging
  19. GRB050522,optical observation
  20. GRB050520,optical observation
  21. XRF 050522: Continued NIR P200 Monitoring
  22. RBO Observations of GRB050522
  23. GRB050509b: optical observations
  24. Recent GRB BVRcIc field photometry
  25. GRB050520: Radio Observations
  26. XRF 050522: Swift XRT observation
  27. XRF050522, BVRcIc field photometry
  28. XRF 050522 : Lulin observations
  29. XRF050522: Optical Observations
  30. XRF050522: Near-infrared Observations
  31. XRF 050522: KAIT observations
  32. XRF 050522 detected with INTEGRAL
  33. GRB 050520: VLT/ULTRACAM observations
  34. Swift UVOT Observations of GRB 050520
  35. GRB 050520: Swift XRT refined analysis
  36. XRF050509C: Chandra Afterglow Detection
  37. XRF 050509c: Swift XRT Upper Limit
  38. XRF050509c: Radio Observations
  39. RBO Observations of GRB050520
  40. GRB 050520: P200 Observations
  41. GRB050520: Liverpool Telescope follow-up
  42. RBO Observations of GRB050520
  43. GRB 050520: TAROT optical limit
  44. GRB 050520: Swift XRT position
  45. GRB 050520: VLT/ULTRACAM observations
  46. GRB 050520: OSN optical observations
  47. GRB 050520: BART optical limit
  48. GRB 050520 - A long GRB detected with INTEGRAL
  49. No Swift-BAT Lightcurves in real-time for next 3 weeks
  50. Swift-BAT trigger 122203 is not a real GRB
  51. XRF 050509C: REM NIR and Optical refined analysis
  52. GRB 050504: Swift XRT afterglow candidate has faded
  53. XRF 050509c optical afterglow
  54. GRB 050509B and short GRB-SN association? (corrected)
  55. GRB 050509B and short GRB-SN association?
  56. GRB 050509B: Subaru Optical Observations
  57. GRB050502b: Early Observation
  58. GRB050509b, Bok telescope B-band imaging
  59. Refined Chandra analysis of GRB 050509b
  60. GRB050509b, SDSS pre-burst observations
  61. GRB 050509b: Keck/Chandra Cross-Correlation
  62. GRB 050509b: Keck/Chandra Cross-Correlation
  63. Chandra observation of GRB 050509b
  64. GRB 050509b: RAPTOR deep, early limits.
  65. GRB050509B: Optical/Infared observations
  66. GRB 050509b: Swift/UVOT follow-up measurements
  67. GRB 050509b Milagro GeV/TeV Observations
  68. GRB050509B: Optical observations at the Very Large Telescope
  69. GRB 050509b: No Optical Variability in XRT Error Circle
  70. GRB050416: Afterglow detection at 188 nm with Swift UVOT
  71. GRB 050509a: Swift-BAT refined analysis
  72. GRB 050509c: ROTSE-III Optical Limits
  73. GRB 050509B: WSRT Radio Observations
  74. GRB050509c: REM NIR and Optical observations (errata corrige to GCN 3400)
  75. GRB 050505, early TAROT observation
  76. GRB050509c (=H3751): An X-Ray Flash Localized By HETE
  77. GRB 050509b: Further Analysis of Keck LRIS Images
  78. GRB050509c: REM NIR and Optical observations
  79. GRB 050509b: Physical Properties of the Candidate Host galaxy
  80. GRB 050505: SARA Observations
  81. Swift UVOT Follow-up Observations of GRB 050509B
  82. GRB 050509B, Optical Observations
  83. GRB 050509B: Swift/XRT refined analysis
  84. GRB050509a: Swift UVOT observations
  85. GRB 050509b: Optical observations
  86. GRB 050509b: Precision Astrometry
  87. GRB 050509b: Possible Optical Counterpart
  88. Keck/DEIMOS Spectrum of Possible Host Galaxy for GRB050509b
  89. GRB 050509A: Optical observations
  90. GRB 050509b: Optical Counterpart Candidate
  91. GRB050509b: Radio Observations
  92. GRB 050509b: PAIRITEL and WIYN Observations
  93. GRB 050509b: Swift-BAT refined analysis of the short hard burst
  94. GRB 050509b: optical observations
  95. GRB 050509b: Swift XRT Position
  96. GRB 050509B: ROTSE-III Optical Limits
  97. Swift Detection of GRB050509b: A short duration burst
  98. GRB 050509a: Swift XRT Position
  99. Swift Detection of the Burst GRB050509
  100. Swift-BAT detection of GRB 050507

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