UGC2238 Scan 132


Observing log information

  Object:           UGC2238
  On scan num:      132 134 136 138 140 142
  Off scan num:     133 135 137 139 141 143
  R.A.:             2.771534 hrs
  Dec.:             13.095544 deg
  On azimuth:       231.468117 deg
  On zenith dist.:  35.118196 deg
  Off azimuth:      231.429122 deg
  Off zenith dist.: 35.100275 deg
  MJD:              52511
  UTC:              0.485660
  Center freq.:     1390.680988 MHz
  Doppler:          0.00009192
  Num. correlators: 2
  Spectrom. atten.: 35 42 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:      0.057 Jy
  Lower 20% velocity: 6254.4 km/s
  Upper 20% velocity: 6630.5 km/s
   Systemic velocity: 6442.5 km/s
   Line width (20%):   376.2 km/s
  Profile integral:   12.85 Jy * km/s
                 A:   11.54
                 B:   13.21
         Ratio B/A:   1.144
  Flux integral
     velocity range:  6181.9 - 6738.9 km/s


looks like two profiles blended, peak flux selection rather arbitrary