Object: NGC4418 On scan num: 74 76 78 80 82 84 Off scan num: 75 77 79 81 83 85 R.A.: 12.448511 hrs Dec.: -0.877777 deg On azimuth: 228.835775 deg On zenith dist.: 51.331301 deg Off azimuth: 228.796475 deg Off zenith dist.: 51.308917 deg MJD: 52419 UTC: 0.165231 Center freq.: 1410.039811 MHz Doppler: -0.00008261 Num. correlators: 2 Spectrom. atten.: 38 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: 0.033 Jy Lower 20% velocity: 2115.8 km/s Upper 20% velocity: 2246.9 km/s Systemic velocity: 2181.3 km/s Line width (20%): 131.1 km/s Profile integral: 3.18 Jy * km/s A: 2.87 B: 3.32 Ratio B/A: 1.154 Flux integral velocity range: 2093.4 - 2262.9 km/s