NGC520 Scan 504


Observing log information

  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

Raw spectrum

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

Figure 1. Unedited spectrum

Measured spectrum

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.

Figure 2. Measured spectrum

Measured parameters

  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