Nebulosities around QSOs |
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| Authors: | R K Thakur R K Sood |
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| Institution: | (1) Dept of Physics, Ravishankar University, Raipur, India;(2) Present address: Govt Science College, Raipur, (M.P.), India |
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| Abstract: | In this paper independent evidence in favour of the hypothesis proposed by Thakur and Sapre (1979) that a QSO consists of a bright central object embedded in an extended nebulosity has been presented. 
U–B
and
B–V
, the spectral indices in (U-B) and (B-V) colours, have been calculated for a sample of 80 QSOs with redshiftz 0.76. In Figure 1  = (
B–V
–
U–V
) has been plotted against   = (
B–V
+
U–B
)/2. In this figure the QSOs in which detectability of neubulosities has been predicted by Thakur and Sapre (1979) occupy a separate but adjacent part of the diagram as compared to those for which such a prediction has not been made. In Figure 2 (U-B)0 has been plotted against (B-V)0 for the same sample of 80 QSOs, where (U-B)0 and (B-V)0 are the (U-B) and (B-V) colours corrected for galactic extinction. In this plot also, a similar separation of the two classes of objects is discernible. Another empirical criterion—namely, (B-V)00.32 for the detectability of nebulosities around QSOs—has been suggested. |
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| Keywords: | |
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