Interstellar medium

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[edit] ESTIMATION OF CARBON COLUMN DENSITY IN THE INTERSTELLAR MEDIUM

Line of sight towards HD 27778 is being studied.


WORK DONE SO FAR

1) UV data from HST obtained using STIS spectrograph is used for the analysis. STIS data are in the form of small chunks.

2) Bin size of all the chunks are made the same by interpolation.

3) Different chunks are coadded using the formulae

X=\frac{\Sigma_{i} \frac{x_{i}}{\sigma_{i}^{2}}}{\Sigma_{i} \frac{1}{\sigma_{i}^{2}}}

\sigma^{2}=\frac{1}{\Sigma_{i} \frac{1}{\sigma_{i}^{2}}}

Likewise different STIS observations are also coadded to form a single spectrum.

4) The stellar continuum is subjected to fourth order polynomial fitting to normalize the spectrum.

5) The form of the interstellar absorption line is a voigt profile, which is the convolution of a lorentzian with a gaussian. Model is constructed with radial velocity v_{\odot}, doppler broadening parameter b and column density N.

6)

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