NGC5157 Scan 252

Contents

Observing log information

  Object:           NGC5157
  On scan num:      252 254 256 258 260 262 264 266 268 270 272 274
  Off scan num:     253 255 257 259 261 263 265 267 269 271 273 275
  R.A.:             13.454819 hrs
  Dec.:             32.028014 deg
  On azimuth:       70.591995 deg
  On zenith dist.:  60.725006 deg
  Off azimuth:      70.570021 deg
  Off zenith dist.: 60.758867 deg
  MJD:              52617
  UTC:              0.352477
  Center freq.:     1386.968608 MHz
  Doppler:          0.00007677
  Num. correlators: 2
  Spectrom. atten.: 38 40 dB
  Bandwidth:        20.0 MHz
  Num. channels:    1024
  Eff. integration: 3360 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 8 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 second-order least squares fit baseline removed using most of the baseline shown in Figure 2.

Figure 3. Measured spectrum

Measured parameters

  Peak intensity:      0.008 Jy
  Lower 20% velocity: 7039.3 km/s
  Upper 20% velocity: 7560.3 km/s
   Systemic velocity: 7299.8 km/s
   Line width (20%):   521.0 km/s
  Profile integral:    2.67 Jy * km/s
                 A:    2.37
                 B:    2.71
         Ratio B/A:   1.142
  Flux integral
     velocity range:  7017.2 - 7588.0 km/s

Comments