Bibcode
Vaduvescu, O.; McCall, M. L.
Bibliographical reference
Astronomy and Astrophysics, Volume 487, Issue 1, 2008, pp.147-160
Advertised on:
8
2008
Journal
Citations
17
Refereed citations
15
Description
Aims: Near-IR photometry of dwarf irregular galaxies (dIs) has been
acquired to expand the sample of objects suitable for investigating the
fundamental plane (FP) discovered previously by us. Data for blue
compact dwarfs (BCDs), dwarf ellipticals (dEs), and dwarf spheroidal
galaxies (dSphs) are amalgamated to evaluate how closely these classes
of galaxies are related to dIs. Methods: Surface brightness
profiles for dIs are modeled using a hyperbolic secant function (sech),
which has been shown to sample the old galaxy component observed in the
NIR (K_s). Also, profiles for BCDs are modeled using a sech function,
but to this is added a Gaussian burst. Kinematics for dIs and BCDs are
constrained by the width W20 of integrated HI line profiles,
and motions within dEs and dSphs are judged from stellar velocity
dispersions. Results: The existence of a FP for dIs is confirmed.
Omitting extreme deviants, the scatter of dIs about the plane is 0.43
mag, somewhat higher than expected from observational errors alone.
Corrections of line widths for tilt do not reduce the residuals, so
motions must be predominantly random. Corrections of surface
brightnesses for tilt have no effect either. BCDs and dEs lie precisely
on the FP defined by dIs, suggesting strong underlying connections among
dIs, BCDs, and dEs.
Based on observations acquired from CTIO, CFHT and 2MASS.