Object: UGC2238 On scan num: 132 134 136 138 140 142 Off scan num: 133 135 137 139 141 143 R.A.: 2.771534 hrs Dec.: 13.095544 deg On azimuth: 231.468117 deg On zenith dist.: 35.118196 deg Off azimuth: 231.429122 deg Off zenith dist.: 35.100275 deg MJD: 52511 UTC: 0.485660 Center freq.: 1390.680988 MHz Doppler: 0.00009192 Num. correlators: 2 Spectrom. atten.: 35 42 dB Bandwidth: 10.0 MHz Num. channels: 1024 Eff. integration: 1800 seconds
This spectrum is the integration of all data for the scan with spectra from both polarizations added together. The spectral intensities are Ssys * (on - off) / off, where Ssys is the system temperature in Jy. The system noise flux density equivalent is calibrated for each scan with a calibration noise source firing during each scan. The cal value, in Jy, is calibrated by comparison with a number of continuum sources as described in the summary web page
This is the section of spectrum measured to obtain the parameters listed below. The three horizontal dotted lines are the baseline, the peak level selected, and 20% of the peak level. The two vertical dotted lines mark the selected 20% line width edges. The solid horizontal line marks the velocity range chosen for the the line profile flux density integral. This spectrum has a second-order least squares fit baseline removed using most of the baseline shown in Figure 1.
Peak intensity: 0.057 Jy Lower 20% velocity: 6254.4 km/s Upper 20% velocity: 6630.5 km/s Systemic velocity: 6442.5 km/s Line width (20%): 376.2 km/s Profile integral: 12.85 Jy * km/s A: 11.54 B: 13.21 Ratio B/A: 1.144 Flux integral velocity range: 6181.9 - 6738.9 km/s
looks like two profiles blended, peak flux selection rather arbitrary