NASA/IPAC EXTRAGALACTIC DATABASE
Date and Time of the Query: 2019-01-19 T18:23:00 PST
Help | Comment | NED Home

For refcode 1997AJ....114.2402C:
Retrieve 1247 NED objects in this reference.
Please click here for ADS abstract

NED Abstract

Copyright by American Astronomical Society. Reproduced by permission
1997AJ....114.2402C OPTICAL ROTATION CURVES AND LINEWIDTHS FOR TULLY-FISHER APPLICATIONS STEPHANE COURTEAU Kitt Peak National Observatory. 950 North Cherry Avenue, Tucson, Arizona 85726 Electronic mail: stephane.courteau@hia.nrc.ca Received 1997 May 20; revised 1997 August 27; accepted 1997 August 27 ABSTRACT We present optical long-slit rotation curves for 304 northern Sb-Sc UGC galaxies from a sample designed for Tully-Fisher (TF) applications. Matching r-band photometry exists for each galaxy. We describe the procedures of rotation curve (RC) extraction and construction of optical profiles analogous to 21 cm integrated linewidths. More than 20% of the galaxies were observed twice or more, allowing for a proper determination of systematic errors. Various measures of maximum rotational velocity to be used as input in the TF relation are tested on the basis of their repeatability, minimization of TF scatter, and match with 21 cm linewidths. The best measure of TF velocity, V_22_ is given at the location of peak rotational velocity of a pure exponential disk. An alternative measure to V_22_ which makes no assumption about the luminosity profile or shape of. the rotation curve is V_hist_, the 20% width of the velocity histogram, though the match with 21 cm linewidths is not as good. We show that optical TF calibrations yield internal scatter comparable to, if not smaller than, the best calibrations based on single-dish 21 cm radio linewidths. Even though resolved H I RCs are more extended than their optical counterpart, a tight match between optical and radio linewidths exists since the bulk of the H I surface density is enclosed within the optical radius. We model the 304 RCs presented here plus a sample of 958 curves from Mathewson et al. (1992, APJS, ,81,413) with various fitting functions. An arctan function provides an adequate simple fit (not accounting for non-circular motions and spiral arms). More elaborate, empirical models may yield a better match at the expense of strong covariances. We caution against physical or "universal" parametrizations for TF applications.
Retrieve 1247 NED objects in this reference.
Please click here for ADS abstract

Back to NED Home