Parameters
Required
 Sky position, galactic, supergalactic, or equatorial (J2000 as 360° decimal) in degrees.
Optional
 Cone (degrees) [default 15°]; plot data points within this cone angle.
 Distance (Mpc); returns model velocity in km/s.
 Velocity (km/s); returns model distance(s) in Mpc – potentially more than one value.
Features
 Model distance – velocity curve (blue) is derived from interpolation of velocities on a grid of distances with grid intervals of 0.2 Mpc at the origin increasing to 1 Mpc intervals at 38 Mpc, the outer limit of the model. The value at a grid point is averaged over the 4 nearest mass points weighted by the inverse square of separation.
 Pause cursor over blue curve for distance and velocity information at chosen location.
 Pause cursor over red crosses for information on data points.
Details
 V_{gsr} (km/s) is the galactic standard of rest velocity; referenced to the center of the Galaxy assuming a circular velocity of Sun of 239 km/s plus local solar motion (van der Marel et al. 2012): V_{gsr} = V_{helio} + 11.1 cos(l) cos(b) + 251 sin(l) cos(b) + 7.25 sin(b)
 PGC1 is the Principal Galaxies Catalog identification of the brightest member of the group contributing to the data point (Kourkchi & Tully 2017).
 The H_{0}=75 dashed line is only for reference. Velocities are observed and distances are determined using the scale zeropoint described by Tully et al. 2016.
 Click on figure for animation of model orbits.
References
 Kourkchi & Tully 2017, ApJ, 843, 16
 Shaya et al. 2017, ApJ, 850, 207
 Tully et al 2016, AJ, 152, 50
 Van der Marel et al. 2012, ApJ, 753, 8
