501-055 Scan 2390


Observing log information

  Object:           501-055
  On scan num:      2390 2392 2394 2396 2398 2400
  Off scan num:     2391 2393 2395 2397 2399 2401
  R.A.:             0.967066 hrs
  Dec.:             30.705168 deg
  On azimuth:       271.642967 deg
  On zenith dist.:  36.812574 deg
  Off azimuth:      271.621214 deg
  Off zenith dist.: 36.783978 deg
  MJD:              52255
  UTC:              0.158657
  Center freq.:     1398.267964 MHz
  Doppler:          -0.00007689
  Num. correlators: 2
  Spectrom. atten.: 34 39 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. Narrow band interference was removed from 5 channels by interpolation between the nearest valid channels

Figure 2. Measured spectrum

Measured parameters

  Peak intensity:      0.005 Jy
  Lower 20% velocity: 4607.1 km/s
  Upper 20% velocity: 4823.6 km/s
   Systemic velocity: 4715.3 km/s
   Line width (20%):   216.5 km/s
  Profile integral:    0.87 Jy * km/s
                 A:    0.81
                 B:    0.75
         Ratio B/A:   0.921
  Flux integral
     velocity range:  4587.3 - 4848.9 km/s


very low SNR, edge locations only guesses