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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. SGR 1900+14: Swift-BAT detection of a bright outburst
  2. GRB 060218SN 2006aj: optical observations at Rozhen Observatory
  3. GRB 060323 : WIDGET simultaneous optical observations
  4. GRB 060323: Early optical observation at Xinglong
  5. GRB060218, optical observations
  6. GRB 060322: Confirmation of Swift XRT afterglow
  7. GRB 060211A: optical observation
  8. GRB060323: optical limit
  9. GRB060211B: optical observation
  10. SGR 1900+14: CORRECTION to GCN 4923
  11. SGR 1900+14: Refined Swift-BAT analysis of the renewed activity
  12. SGR 1900+14: Swift detection of renewed activity
  13. GRB060323: NOT optical observations
  14. GRB 060322: IAC80 optical observations
  15. GRB 060322: Swift XRT afterglow candidate
  16. GRB060323: P60 Observations
  17. GRB 060323: Swift/UVOT Observations
  18. GRB 060323: optical afterglow confirmed
  19. GRB060323: NOT observations
  20. GRB 060323: Optical Observations
  21. GRB 060323: Tautenburg OT candidate retraction
  22. GRB 060323: Refined analysis of the Swift-BAT burst
  23. GRB 060323: optical observations at TNG
  24. GRB 060323: Swift XRT refined analysis
  25. GRB 060323: BVRI observations at Tautenburg, aftreglow candidate
  26. GRB 060323: Swift/XRT position
  27. GRB 060322: Refined analysis of the Swift-BAT burst
  28. GRB060323, optical observation
  29. GRB060323 - SDSS Pre-Burst Observations
  30. GRB 060323: Swift detection of a burst with a possible optical afterglow
  31. GRB 060322: Swift-BAT detection of a 200-sec burst
  32. GRB060219: optical observation
  33. GRB060206: optical observation
  34. GRB060218/SN2006aj: optical observations
  35. GRB 060218/SN 2006aj, LNA optical observation
  36. GRB060218: Refined photometric calibration of comparison stars
  37. GRB 060319: WHT K-band candidate afterglow
  38. GRB 060319: IAC-80 optical observations
  39. GRB060319: Swift XRT refined analysis
  40. GRB060319: Swift/UVOT upper limits
  41. GRB 060319: Re-analysis of TNG data
  42. GRB060319: MASTER limit
  43. GRB 060319: Swift-BAT refined analysis
  44. GRB 060319 optical observations at TNG
  45. GRB060319 : Liverpool Telescope optical limit
  46. GRB060319: MASTER optical observation
  47. GRB060319 - SDSS Pre-burst Observations
  48. GRB060319: Swift/XRT position
  49. GRB 060319: Swift detection of a burst
  50. GRB060313: Radio Observations
  51. GRB 060313: early afterglow NIR upper limits with REM
  52. IBAS Alert n. 3221: not a GRB
  53. Konus-Wind observation of GRB 060313
  54. GRB060313: SSO 40inch Observations
  55. GRB 060313: Further analysis of the Swift-BAT bright short hard burst
  56. GRB 060313: PROMPT Observations
  57. GRB 060313: Swift/UVOT Observations
  58. GRB060313:Gemini South Observations
  59. GRB 060313: Swift-XRT team refined analysis
  60. GRB060313: optical observations of the afterglow candidate
  61. GRB 060313: Refined analysis of the Swift-BAT bright short hard burst
  62. GRB 060313, SMARTS optical counterpart?
  63. GRB 060313: Possible optical counterpart
  64. GRB 060313: Swift XRT position
  65. GRB 060313, SMARTS optical/IR observations
  66. GRB060313: optical and near infrared observations with REM
  67. GRB 060313: Swift-BAT detection of a bright short hard burst
  68. GRB060218: SARA Observations of SN2006aj
  69. GRB060312: Swift UVOT observation
  70. GRB 060312: Refined analysis of the Swift-BAT burst
  71. GRB 060218/SN 2006aj, high resolution spectra
  72. GRB 060312: Swift XRT team refined analysis
  73. GRB060306: APO Ks-band Imaging Observations
  74. GRB 060312: ROTSE-III Optical Limits
  75. GRB 060312: Swift detection of a burst
  76. IBAS Alert n. 3218 : not a real GRB
  77. GRB 060306: SOAR Ks Observations
  78. Bright short hard GRB 060303: IPN localization and Konus spectrum
  79. GRB060219: Liverpool Telescope observations
  80. GRB 060306: MAGNUM observations
  81. GRB060218: analysis of the XMM-Newton observation
  82. Swift/UVOT observations of GRB060306
  83. GRB 060306: Swift-BAT refined analysis
  84. GRB 060306: Swift-XRT team refined analysis
  85. GRB 060306: PROMPT Observations
  86. GRB 060306: Swift detection of a bright burst
  87. GRB 060218: RTT150 optical observations
  88. GRB060218: Ep,i - Eiso correlation
  89. GRB060218: R-band CCD photmetry
  90. GRB060223b: optical limit
  91. GRB060218/SN 2006aj: optical observation in V
  92. GRB060218/SN 2006aj: optical observation
  93. GRB 060121: HST observations
  94. GRB 060218 : GMRT observation [Correction and Improvement]
  95. GRB 060223b: Swift/UVOT Upper Limits
  96. GRB 060218/SN 2006aj: K-380 optical observations
  97. GRB 060218/SN 2006aj, SMARTS optical/IR observations
  98. GRB200618: optical polarimetry and photometry
  99. GRB 060223B: Swift XRT possible afterglow
  100. GRB 060218/SN 2006aj: ABT observations

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