Object: NGC6821 On scan num: 136 138 140 142 144 146 Off scan num: 137 139 141 143 145 147 R.A.: 19.740031 hrs Dec.: -6.833798 deg On azimuth: 131.568975 deg On zenith dist.: 58.411344 deg Off azimuth: 131.529374 deg Off zenith dist.: 58.435780 deg MJD: 52353 UTC: 0.437708 Center freq.: 1413.338708 MHz Doppler: 0.00008613 Num. correlators: 2 Spectrom. atten.: 39 40 dB Bandwidth: 10.0 MHz Num. channels: 1024 Eff. integration: 1740 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 spectrum is the same as Figure 1 but with 2 60-second sub-integrations manually deleted because of interference or a bad baseline.
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 2.
Peak intensity: 0.168 Jy Lower 20% velocity: 1436.7 km/s Upper 20% velocity: 1609.9 km/s Systemic velocity: 1523.3 km/s Line width (20%): 173.2 km/s Profile integral: 21.08 Jy * km/s A: 19.55 B: 20.93 Ratio B/A: 1.071 Flux integral velocity range: 1395.9 - 1645.7 km/s