NGC985 Scan 541

Contents

Observing log information

  Object:           NGC985
  On scan num:      541 543 545 547 549 551 553 555 557 559 561 563 565 567
  Off scan num:     542 544 546 548 550 552 554 556 558 560 562 564 566 568
  R.A.:             2.577052 hrs
  Dec.:             -8.785516 deg
  On azimuth:       223.491093 deg
  On zenith dist.:  57.911530 deg
  Off azimuth:      223.453857 deg
  Off zenith dist.: 57.891164 deg
  MJD:              52280
  UTC:              0.134942
  Center freq.:     1362.770912 MHz
  Doppler:          -0.00008947
  Num. correlators: 2
  Spectrom. atten.: 33 40 dB
  Bandwidth:        10.0 MHz
  Num. channels:    1024
  Eff. integration: 4200 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:      0.006 Jy
  Lower 20% velocity: 12591.5 km/s
  Upper 20% velocity: 13188.0 km/s
   Systemic velocity: 12889.8 km/s
   Line width (20%):   596.5 km/s
  Profile integral:    2.35 Jy * km/s
                 A:    1.94
                 B:    2.00
         Ratio B/A:   1.035
  Flux integral
     velocity range:  12508.9 - 13248.9 km/s

Comments

extremely low SNR, profile edge locations are strictly guesses