Object: NGC4490 On scan num: 10 12 14 Off scan num: 11 13 15 R.A.: 12.510247 hrs Dec.: 41.639655 deg On azimuth: 60.539346 deg On zenith dist.: 56.381571 deg Off azimuth: 60.520905 deg Off zenith dist.: 56.415705 deg MJD: 52553 UTC: 0.487975 Center freq.: 1417.783971 MHz Doppler: 0.00003533 Num. correlators: 2 Spectrom. atten.: 35 34 dB Bandwidth: 10.0 MHz Num. channels: 1024 Eff. integration: 900 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: 1.468 Jy Lower 20% velocity: 454.6 km/s Upper 20% velocity: 697.0 km/s Systemic velocity: 575.8 km/s Line width (20%): 242.4 km/s Profile integral: 250.30 Jy * km/s A: 229.34 B: 253.71 Ratio B/A: 1.106 Flux integral velocity range: 399.6 - 740.9 km/s