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Transferring mag to erg/cm$^2$/s

Stellar magnitudes, provided by observations in an optical band, are reduced to the units of erg/cm$^2$/s as follows:

\begin{displaymath}
F_i = \Delta {\lambda}_i   10^{-0.4 m_i-A_i^0}   ,
\end{displaymath} (4.1)

where `zero-point' $A_i^0$ and effective widths $\Delta {\lambda}_i$ are collected in Table [*].


Table: `Zero-points', central wavelengths, and effective widths of optical bands (Zombeck's Handbook, 1990). $^*$ - the corrected value (the handbook value is given in parentheses).
  $A^0_i$ $\lambda$, Angstreom      $\Delta {\lambda}_i$, Angstreom     
U $8.37$ $3650$ $680$
B $8.198^*$ ($8.18$) $4400$ $980$
V $8.44$ $5500$ $890$

The $^*$-value is corrected by us according to the paper by Bochkarev et al (1991), where disk color indexes are calculated with a certain distribution of the temperature along the radius and the real shapes of transmission bands of optical filters are taken into account. We have achieved coincidence between theoretical values by Bochkarev et al (1991) and ours, obtained with rectangular shapes of transmission band of optical filters. For the effect, it was enough to correct the value of `zero-point' for B band.

Refs:

Бочкарев и др. (Bochkarev N.G., Karitskaya E.A., Shakura N.I., Zhekov S.A.) // Astron. Astrophys. Trans., 1991, V. 1, P. 41.

Zombeck M.V. // Handbook of Astronomy and Astrophysics, 1990, Cambridge, UK. http://adsbit.harvard.edu/books/hsaa/index.html


next up previous
Next: About this document ... Up: xnov Previous: 9.3-37.2 keV light curve
Lipunova Galina 2002-01-14