N_992 Scan 550


Observing log information

  Object:           N_992
  On scan num:      550 552 554 556 558 560
  Off scan num:     551 553 555 557 559 561
  R.A.:             2.623809 hrs
  Dec.:             21.101257 deg
  On azimuth:       217.176680 deg
  On zenith dist.:  20.698025 deg
  Off azimuth:      217.165775 deg
  Off zenith dist.: 20.695942 deg
  MJD:              52267
  UTC:              0.108866
  Center freq.:     1400.905197 MHz
  Doppler:          -0.00007605
  Num. correlators: 2
  Spectrom. atten.: 34 40 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:      0.084 Jy
  Lower 20% velocity: 3977.4 km/s
  Upper 20% velocity: 4308.1 km/s
   Systemic velocity: 4142.7 km/s
   Line width (20%):   330.7 km/s
  Profile integral:   18.75 Jy * km/s
                 A:   15.14
                 B:   18.14
         Ratio B/A:   1.198
  Flux integral
     velocity range:  3919.5 - 4368.7 km/s


quite asymmetric profile