NGC_6822 Scan 581

Contents

Observing log information

  Object:           NGC_6822
  On scan num:      581
  Off scan num:     582
  R.A.:             19.748900 hrs
  Dec.:             -14.801667 deg
  On azimuth:       211.874639 deg
  On zenith dist.:  59.246830 deg
  Off azimuth:      211.836142 deg
  Off zenith dist.: 59.231052 deg
  MJD:              52523
  UTC:              0.162338
  Center freq.:     1419.353521 MHz
  Doppler:          -0.00007421
  Num. correlators: 2
  Spectrom. atten.: 44 42 dB
  Bandwidth:         5.0 MHz
  Num. channels:    1024
  Eff. integration: 300 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:     12.350 Jy
  Lower 20% velocity:  -89.0 km/s
  Upper 20% velocity:  -30.5 km/s
   Systemic velocity:  -59.8 km/s
   Line width (20%):    58.5 km/s
  Profile integral:   479.69 Jy * km/s
                 A:   445.75
                 B:   477.25
         Ratio B/A:   1.071
  Flux integral
     velocity range:  -120.6 -  -15.5 km/s

Comments