in - integrate a part of stack 1 EXAMPLES: in 40,60 Integrate from 40 to 60 Km/s (if horiz plot units are Km/s). Print the results and put in area1. cr 2;in,x(0),x(1) Read the cursor twice and integrate between those limits. This is the macro "crin" in !0 !1 dp:;v ?(.area arg3 * the error in the area and otherwise gives DRAGON (aka IEEE NaN, aka BLANK). in clip:1,1 Use only channels with ABS(temperature) greater than the stack rms value (.rms) in calculating all moments. in clip:disp:2 Use only channels with ABS(temperature) greater than twice the stack rms value (.rms) in calculating the second moment (velocity dispersion). DESCRIPTION: Integrate the spectrum in stack 1 over a given horizontal interval. The results in horizontal plot units are printed unless suppressed by the 'dp:' flag (a header is also printed). The result in K*Km/s is put in the header variable 'area1' and the expected error in the area based on the rms is put in 'arerr1'. The horizontal interval is specified in horizontal plot units. The centroid (first moment) is also calculated (horizontal value at which half of the integral is reached). The value of the centroid is put in the header variable 'vcent1'. This integration may include fractional channels at each end. The dispersion (second moment) is calculated as: disp = sqrt[SUM(T_i(v_i-vcent)^2)/SUM(T_i)] where T_i and v_i are the temperature and velocity of the i-th channel, respectively. The result is put in fwhm1. Note for a purely Gaussian line, the true full-width at half-maximum is sqrt(8ln(2)) times the dispersion. Clipping levels (clip:) are applied to the moment calculations such that channels with values between -(clip*.rms) and +(clip*.rms) are not used. Thus it is important that the value of .rms is correct. The default clip levels are 0 for area and centroid (zeroth and first moments) and 1 for dispersion (second moment). Since the centroid is calculated directly from the area, it always takes the same clip level as the area. ERRORS: If the range of integration extends outside the stack, you will be warned. If you agree to continue, no more of those warnings will be given on the same command line. The computed values will be based on the portion of the range inside the limits of the stack. If the limits of integration are completely outside of the stack, a similar set of warnings will be given, but the value returned will be DRAGON (.DR). If the square of the second moment is negative, .fwhm will be set to DRAGON. This usually means the clip level was too low or that the integration limits have been poorly chosen.