lambdaR: Function to compute the angular momentum parameter lambda_R...

Description Usage Arguments Details Value Author(s) References See Also

Description

Function to compute the angular momentum parameter lambda_R from the kinematic map of a galaxy. The parameter is defined by Emsellem et al. (2007) as

λ_R = \frac{\langle R\,|V|\rangle}{R√{V^2 + σ^2}}

Usage

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lambdaR(kinmap, config, SN.lim = 0, SN.plot = FALSE, Lcent = NULL, Mcent
  = NULL, title = "NULL", errors = 0, error.scale = NULL, v.err = NULL,
  sig.err = NULL, ...)

Arguments

kinmap

a kinematic map with velocity and velocity dispersion, given as a file name, an object of class kinmap or as a data.frame containing the relevant columns

config

configuration file for the system at hand. The function requires the coordinates of the centre of the galaxy if these are not specified explicitely.

SN.lim

Lower signal-to-noise limit of data points that are to be used in the computation.

SN.plot

Create a plot of λ_R against signal-to-noise limit. This clarifies the dependence on SN.lim and may help in choosing an appropriate value.

Lcent, Mcent

Centre coordinates of the galaxy in the kinematic map. These values have priority over those in the configuration file.

title

A title for the SN.plot.

errors

number of Monte Carlo simulations to simulate errors on lambda.R

error.scale

If v.err and sig.err are not given, then they are computed from the interval between dv.high and dv.low (same for sig), scaled by error.scale

v.err, sig.err

dispersion of Gaussian distributions used to obtain Monte Carlo kinmaps for v and sigma

...

further arguments passed to or from other methods.

Details

The value of lambda_R computed here is uncorrected.

Value

a number

Author(s)

Oliver Czoske

References

Emsellem, E. et al.: "The SAURON project - IX. A kinematic classification for early-type galaxies", MNRAS 379, 401 (2007)

See Also

binney


oczoske/slacR documentation built on May 20, 2019, 8:23 p.m.