# Tag Info

7

The luminosity of normal stars is a strongly increasing function of mass. e.g. $L \propto M^3$. If another star is "hidden" in a binary system, then it is of lower mass. So the amount of hidden mass is less than what is seen. Of course this can (and is) be accounted for when estimating the mass present in luminous matter because we know typical ...

3

A few sources come to mind to add to MAST and Sloan. Data releases from the SAMI Galaxy survey, which contain (or will eventually contain) emission line spectra for about 3500 galaxies. The papers for the first two releases can be found [here] and [here]. Another (smaller and older) dataset can be found at the Penn State Center for Astrophysics. It contains ...

3

I'm not a spectroscopist, but, I know a fair bit about spacecraft data reduction. CRISM is a spectrometer that's very sensitive, but it needs more light than it can get by just riding along with the spacecraft, so it slews in the reverse direction of motion (that's why CRISM images have that hourglass shape). Despite that, it STILL has some light issues ...

2

In this case itseems to mean that the depth of the line is 7 times its error bar below the continuum level. Impossible to answer. You say it can't be done, but the authors say that they fitted a Gaussian. You either use a rough estimate (attributable to Cayrel de Strobel 1988) of $$\Delta {\rm EW} \sim 1.5\frac{\sqrt{RP}}{{\rm SNR}},$$ where $R$ is the ...

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