Object: NGC520 On scan num: 504 506 508 510 512 514 Off scan num: 505 507 509 511 513 515 R.A.: 1.409814 hrs Dec.: 3.793625 deg On azimuth: 162.773506 deg On zenith dist.: 35.719778 deg Off azimuth: 162.738388 deg Off zenith dist.: 35.724752 deg MJD: 52522 UTC: 0.294942 Center freq.: 1409.835028 MHz Doppler: 0.00006022 Num. correlators: 2 Spectrom. atten.: 35 38 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: 0.139 Jy Lower 20% velocity: 2055.3 km/s Upper 20% velocity: 2307.1 km/s Systemic velocity: 2181.2 km/s Line width (20%): 251.8 km/s Profile integral: 22.42 Jy * km/s A: 20.88 B: 22.15 Ratio B/A: 1.061 Flux integral velocity range: 1985.8 - 2332.8 km/s
2 or 3 profiles together, measured strongest part at lower velocity