Mrk331 Scan 159


Observing log information

  Object:           Mrk331
  On scan num:      159 161 163 165 167 169
  Off scan num:     160 162 164 166 168 170
  R.A.:             23.857455 hrs
  Dec.:             20.586131 deg
  On azimuth:       253.653117 deg
  On zenith dist.:  38.168130 deg
  Off azimuth:      253.615212 deg
  Off zenith dist.: 38.136760 deg
  MJD:              52421
  UTC:              0.643067
  Center freq.:     1394.738543 MHz
  Doppler:          0.00007841
  Num. correlators: 2
  Spectrom. atten.: 35 42 dB
  Bandwidth:        10.0 MHz
  Num. channels:    1024
  Eff. integration: 1440 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

Edited spectrum

This spectrum is the same as Figure 1 but with 12 60-second sub-integrations manually deleted because of interference or a bad baseline.

Figure 2. Edited 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 6th-order least squares fit baseline removed using most of the baseline shown in Figure 2.

Figure 3. Measured spectrum

Measured parameters

  Peak intensity:      0.041 Jy
  Lower 20% velocity: 5227.4 km/s
  Upper 20% velocity: 5610.3 km/s
   Systemic velocity: 5418.8 km/s
   Line width (20%):   382.9 km/s
  Profile integral:   13.69 Jy * km/s
                 A:   11.92
                 B:   13.68
         Ratio B/A:   1.147
  Flux integral
     velocity range:  5201.0 - 5643.2 km/s


very poor baseline, flux density integral very inaccurate