Dwarf lenticular galaxies: structure and evolutionary census
Silchenko Olga K. and Startseva Marina A. Sternberg Astronomical
Institute, Moscow, Russia Moiseev Alexei V. Special Astrophysical
Observatory, Nizhnij Arkhyz, Russia Slide 2 Where have S0s come
from? Fasano et al. (2000): At z>0.5 the population of S0s in
clusters (where they dominate presently) is negligible, so they
have formed 3-4 Gyr ago `en mass. so they have formed 3-4 Gyr ago
`en mass. Wilman et al. (2009): At z=0.4 many S0s form IN GROUPS,
at their outskirts, so they form probably through gravitational
interaction. Slide 3 The NGC 80 group as a probable situ of S0
formation Massive (>10 14 solar masses, Ramella et al. 2002)
Massive (>10 14 solar masses, Ramella et al. 2002) Rich (45
bright members, Mahdavi and Geller 2004) Rich (45 bright members,
Mahdavi and Geller 2004) X-ray luminous (log L X = 42.56, Mahdavi
et al. 2000) X-ray luminous (log L X = 42.56, Mahdavi et al. 2000)
BUT disk galaxies dominate (only 3 Es). BUT disk galaxies dominate
(only 3 Es). Slide 4 The NGC 80 group as a probable situ of S0
formation Optical image (DSS) X-ray image (ASCA) Slide 5 Startseva,
Silchenko & Moiseev (2009): Astronomy Reports, in press
Two-colour (BV) surface photometry of 13 disk galaxies with the
SCORPIO of the 6m telescope; Two-colour (BV) surface photometry of
13 disk galaxies with the SCORPIO of the 6m telescope; 9 of them
are classified by us as S0s 9 of them are classified by us as S0s
Slide 6 Startseva, Silchenko & Moiseev (2009): Astronomy
Reports, in press We have used the software GIDRA (Moiseev et al.
2004) to decompose two-dimensional images into Sersic components
iteratively, starting from the outermost parts. We have used the
software GIDRA (Moiseev et al. 2004) to decompose two-dimensional
images into Sersic components iteratively, starting from the
outermost parts. All S0s but two have appeared to possess two-
tiers (`antitruncated) disks and exponential bulges
(`pseudobulges?); All S0s but two have appeared to possess two-
tiers (`antitruncated) disks and exponential bulges
(`pseudobulges?); The remaining two which are the smallest contain
only one exponential component (a disk?) The remaining two which
are the smallest contain only one exponential component (a disk?)
Slide 7 Types of disk surface-brightness profiles: Exponential
Truncated Freemans type II Antitruncated Pohlen & Trujillo 2006
Slide 8 Two dwarf S0s fainter than M B =-17.5, both are located
close to giant galaxies A satellite of NGC 80 (central group
galaxy) A satellite of NGC 86 Slide 9 and both have pure disk
structure no bulges Slide 10 From UCM0018+2216 there is a smooth
transition to the second part of the topic According to Gallego et
al. (1996) and to the data in their survey of emission-line
galaxies UCM, this galaxy demonstrates a moderate-strength star
formation burst. According to Gallego et al. (1996) and to the data
in their survey of emission-line galaxies UCM, this galaxy
demonstrates a moderate-strength star formation burst. Many other
(most?) dwarf lenticulars in groups reveal also signs of
current/recent star formation. Many other (most?) dwarf lenticulars
in groups reveal also signs of current/recent star formation. Slide
11 The sample of nearby S0s by Silchenko (2008): a subsample of
faint group S0s All are very young! All are very young! Slide 12
Images (SDSS) NGC 3156 NGC 5379 NGC 3418 NGC 5574 Slide 13 SDSS
colour maps (g-r) NGC 3156NGC 3418 NGC 5379NGC 5574 Slide 14 Our
own colour mapping: NGC 509 Slide 15 NGC 3156: a disk-dominated S0
Slide 16 NGC 3156: young stars in the nucleus SAURON data, January
2002 Slide 17 NGC 3156: gas over the disk SAURON data, January 2002
[OIII] 5007 Slide 18 NGC 5379: a disk-dominated S0 A ring of star
formation? A ring of star formation? Solid-body rotation?
Solid-body rotation? Slide 19 NGC 5379: star formation over the
whole disk SCORPIO data, March 2008 nucleus 10 off20 off Slide 20
NGC 5379: radial gas motions or inner polar disk? SAURON data,
April 2007 [OIII] 5007 Slide 21 NGC 5379: complex pattern of the
stellar velocity dispersion The young (disk-like?) nucleus and a
ring of young stars shrudded by the dust Slide 22 Conclusions
`Downsizing in groups: small S0s are forming just now while giant
S0s have formed 3-4 Gyr ago. `Downsizing in groups: small S0s are
forming just now while giant S0s have formed 3-4 Gyr ago.
Mechanisms of transformation may be various: minor merging with
gas-rich dwarfs for `isolated group members, `harassment for
satellites of giant galaxies. Mechanisms of transformation may be
various: minor merging with gas-rich dwarfs for `isolated group
members, `harassment for satellites of giant galaxies. Small S0s
are almost bulgeless long in the course of shaping; so for giant
well-shaped S0s we may suggest late growth of their large
pseudobulges and/or original presence of large `classic bulges.
Small S0s are almost bulgeless long in the course of shaping; so
for giant well-shaped S0s we may suggest late growth of their large
pseudobulges and/or original presence of large `classic bulges.
Slide 23 Acknowledgements This paper makes use of data obtained
from the Isaac Newton Group Archive which is maintained as part of
the CASU Astronomical Data Centre at the Institute of Astronomy,
Cambridge. This paper makes use of data obtained from the Isaac
Newton Group Archive which is maintained as part of the CASU
Astronomical Data Centre at the Institute of Astronomy, Cambridge.
We use also the photometric images of the galaxies obtained in the
frame of the SDSS project. Funding for the Sloan Digital Sky Survey
(SDSS) and SDSS-II has been provided by the Alfred P. Sloan
Foundation, the Participating Institutions, the National Science
Foundation, the U.S. Department of Energy, the National Aeronautics
and Space Administration, the Japanese Monbukagakusho, and the Max
Planck Society, and the Higher Education Funding Council for
England. The SDSS Web site is http://www.sdss.org/. We use also the
photometric images of the galaxies obtained in the frame of the
SDSS project. Funding for the Sloan Digital Sky Survey (SDSS) and
SDSS-II has been provided by the Alfred P. Sloan Foundation, the
Participating Institutions, the National Science Foundation, the
U.S. Department of Energy, the National Aeronautics and Space
Administration, the Japanese Monbukagakusho, and the Max Planck
Society, and the Higher Education Funding Council for England. The
SDSS Web site is http://www.sdss.org/. The most of our data have
been obtained at the 6m telescope of the Special Astrophysical
Observatory of the Russian Academy of Sciences. The most of our
data have been obtained at the 6m telescope of the Special
Astrophysical Observatory of the Russian Academy of Sciences. Slide
24 Kormendys diagram
