computing error in EW

rohit wrote on Apr 27, 2009

I use the SPLOT task to obtain the equivalent width, however, IRAF does not give me the precision or the error involved in measuring EW. Is there something I need to enable? How do I get the error in EW?

Thanks,

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Francisco Valdes wrote on Apr 27, 2009

The parameters you want are nerrsample, sigma0, and nerrsample. Read the help for a description of the parameters and the algorithm. Some hints, sigma0 is basically the standard deviation of a clean area of the continuum. The invgain is harder to determine and you may just want to skip using it and assume the pixel uncertainties are independent of signal level.

Frank Valdes

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Last post on Apr 27, 2009