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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 060602B: Swift/UVOT observations
  2. GRB 060602A: Swift-BAT Refined Analysis
  3. GRB 060602B: RTT150 optical observations
  4. GRB 060211A : WIDGET simultaneous optical observations
  5. GRB060602A: optical observations(/transient?)
  6. GRB 060526: Tautenburg Second Epoch Observations
  7. GRB060602A: Bootes-IR observations
  8. GRB 060602B: Swift detection of a burst
  9. GRB060602B: Watcher observations - no OT candidate
  10. GRB060602B: BOOTES-IR candidate afterglow
  11. GRB060602 - SDSS Pre-Burst Observations
  12. GRB 060602: Swift detection of a burst
  13. GRB 060502A: Optical afterglow observations
  14. GRB 060526: Break in X-ray light curve
  15. GRB 060526: RTT150 optical observations
  16. GRB060526, optical observations
  17. GRB 051227 : WIDGET simultaneous optical observations
  18. GRB 051028 : WIDGET pre-trigger limit
  19. GRB 060526: RTT150 optical observations
  20. GRB 060526: Multiple Optical Flares
  21. GRB060526: afterglow fitting and probable jet break
  22. GRB 060526: RTT150 optical observations
  23. GRB060526: Optical counterpart from MIRO
  24. GRB060502b: optical observations
  25. GRB 060526: RTT150 optical observations
  26. GRB 060526: Tautenburg OT observation and light curve fitting
  27. GRB060526: optical observations
  28. GRB 060526: SMARTS optical/IR afterglow observations
  29. GRB060526: possible break in the optical light curve
  30. GRB 060526: REM observations
  31. GRB 060526: RTT150 optical observations, afterglow flattening
  32. GRB 060526: Optical Flare
  33. GRB 060526: MDM-2.4m Observations
  34. GRB 060526: Refined analysis of the Swift-BAT burst
  35. GRB 060526: RTT150 optical observations
  36. GRB060526: Further Swift-UVOT Observations
  37. GRB060526, optical observations
  38. GRB 060526: Magellan Redshift
  39. GRB 060526 Lulin optical observation
  40. GRB 060526: Swift/XRT Team refined analysis
  41. GRB 060526: TNG optical observations
  42. GRB 060526: ROTSE-III Observations of Optical Counterpart
  43. GRB 060526: Watcher Observations
  44. GRB060526 - SDSS Pre-burst Observations
  45. GRB 060526: Continued emission for the Swift burst
  46. GRB 060526: Swift detection of a burst with x-ray and optical afterglow
  47. GRB060505: VLT observations of the optical afterglow
  48. GRB 060413 : WIDGET simultaneous optical observations
  49. GRB 060522: Swift/UVOT Observations: Correction
  50. GRB 060522: Swift/UVOT Observations of the Optical Afterglow
  51. XMM-Newton observation of GRB060510b
  52. GRB060512: Late-Time P200 Observations
  53. GRB060522: z = 5.11 Keck-LRIS Redshift
  54. GRB 060522: Swift/XRT Team refined analysis
  55. GRB 060522: Swift-BAT Refined Analysis
  56. GRB 060522: REM NIR observations
  57. GRB 060522: TNG optical observations
  58. GRB 060522: Swift detection of a burst with possible optical afterglow
  59. GRB 060512: reanalysis of optical spectra
  60. GRB 060515: NIR observation
  61. GRB 060210: Jet Break in the XRT light curve
  62. GRB 060516: Refined analysis of the Swift-BAT burst
  63. GRB 060512: TNG optical spectroscopy
  64. GRB 060516: Swift detection of a burst
  65. GRB060515: P200 NIR Observations
  66. GRB 060505 BAT refined analysis
  67. GRB 060515 BAT refined analysis
  68. GRB 060512: TAROT optical observation
  69. GRB 060515: Swift/XRT Team refined analysis
  70. GRB 060515: Swift/UVOT Upper Limits
  71. GRB 060515: Swift/XRT position
  72. GRB 060515: Super-LOTIS Observations
  73. GRB060515: Swift/UVOT initial observation
  74. GRB 060515: TAROT optical observation
  75. GRB 060515: ROTSE-III Optical Limits
  76. GRB 060515: Swift detection of a burst
  77. VLT optical spectroscopy of GRB 060512
  78. Swift/UVOT observations of GRB060512.
  79. GRB 060512: Subaru NIR observation
  80. GRB060512: Swift XRT Team refined analysis
  81. GRB 060512: 1.54m Kuiper Observations
  82. GRB 060512: Detection of NIR afterglow
  83. GRB 060512: P60 Observations
  84. GRB 060512: Swift-BAT Refined Analysis
  85. GRB 060505 - OT candidate + galaxy spectrum
  86. GRB 060512: optical decay
  87. GRB 060512: REM NIR observations
  88. GRB060512 - SDSS Pre-Burst Observations
  89. GRB060512 Name Correction: LT Afterglow detection
  90. GRB060512: Liverpool Telescope Afterglow detection
  91. GRB 060512: Swift detection of a burst with an optical afterglow
  92. GRB 060510A: Swift/UVOT Detection of an Optical Afterglow
  93. GRB 060505: X-ray afterglow - Correction -
  94. GRB 060505: X-ray afterglow
  95. Konus-Wind observation of GRB 060510A
  96. GRB060418: optical observations
  97. GRB 060428a, SMARTS optical/IR afterglow detection
  98. GRB060510B: Swift XRT refined analysis
  99. GRB 060510B: Swift/UVOT Upper Limits
  100. GRB 060510A: Refined analysis of the Swift-BAT burst

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