Bibcode
Penny, S. J.; Masters, Karen L.; Weijmans, Anne-Marie; Westfall, Kyle B.; Bershady, Matthew A.; Bundy, Kevin; Drory, Niv; Falcón-Barroso, J.; Law, David; Nichol, Robert C.; Thomas, Daniel; Bizyaev, Dmitry; Brownstein, Joel R.; Freischlad, Gordon; Gaulme, Patrick; Grabowski, Katie; Kinemuchi, Karen; Malanushenko, Elena; Malanushenko, Viktor; Oravetz, Daniel; Roman-Lopes, Alexandre; Pan, Kaike; Simmons, Audrey; Wake, David A.
Bibliographical reference
Monthly Notices of the Royal Astronomical Society, Volume 462, Issue 4, p.3955-3978
Advertised on:
11
2016
Citations
31
Refereed citations
30
Description
Using kinematic maps from the Sloan Digital Sky Survey (SDSS) Mapping
Nearby Galaxies at Apache Point Observatory (MaNGA) survey, we reveal
that the majority of low-mass quenched galaxies exhibit coherent
rotation in their stellar kinematics. Our sample includes all 39
quenched low-mass galaxies observed in the first year of MaNGA. The
galaxies are selected with Mr > -19.1, stellar masses
109 M⊙ < M* < 5 ×
109 M⊙, EWHα < 2 Å,
and all have red colours (u - r) > 1.9. They lie on the
size-magnitude and σ-luminosity relations for previously studied
dwarf galaxies. Just six (15 ± 5.7 per cent) are found to have
rotation speeds ve, rot < 15 km s-1 at ˜1
Re, and may be dominated by pressure support at all radii.
Two galaxies in our sample have kinematically distinct cores in their
stellar component, likely the result of accretion. Six contain ionized
gas despite not hosting ongoing star formation, and this gas is
typically kinematically misaligned from their stellar component. This is
the first large-scale Integral Field Unit (IFU) study of low-mass
galaxies selected without bias against low-density environments.
Nevertheless, we find the majority of these galaxies are within
˜1.5 Mpc of a bright neighbour (MK < -23; or
M* > 5 × 1010 M⊙),
supporting the hypothesis that galaxy-galaxy or galaxy-group
interactions quench star formation in low-mass galaxies. The local
bright galaxy density for our sample is ρproj = 8.2
± 2.0 Mpc-2, compared to ρproj = 2.1
± 0.4 Mpc-2 for a star-forming comparison sample,
confirming that the quenched low-mass galaxies are preferentially found
in higher density environments.