The ionized gas kinematics in dwarf galaxies:

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The ionized gas kinematics in dwarf galaxies 3D
spectroscopic study
Alexei Moiseev Special Astrophysical
Observatory, Nizhnij Arkhyz, Russia
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• Introduction
• velocity fields
• Fabry-Perot interferometers
• Kinematics of dIrr and BCDG
• Effects of starformation (outflow, bubles...)
• Mergers
• Polar rings and disks

SCORPIO multi-mode focal reducer with scanning
FPI
SAO RAS 6-m telescope
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Velocity fields of galactic disk
Thick disk approximation

• Non-circular gas motions
• bar and spiral arms
• active galactic nucleus
• violent starformation
• interacting galaxies, mergers

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Fabry-Perot Interferometer
Interferogram of M51 (Tully, 1974)
1901 Fabry Ch. Perot A. On a New Form of
Interferometer (ApJ, 13, 265) 1914 Buisson H.,
Fabry Ch. Bourget H. turned a FP etalon on the
Orion nebula 1950-60 Courtes G. et al. revived
this technique for observations of
HII-regions 1974 Tully R.B., constructed the
first spectrophotometric data-cube (M
51) 1980-90s the piezoelectrically IFP
panoramic detectors (photon counters and
CCDs) TAURUS (Taylor K. Atherthon P.), CIGALE
(Boulesteix J. et al) Now New generation
devices for large telescopes SCORPIO
(BTA, 6-m), Kyoto3D (SUBARU) New
generation photon counters FaNTOmM,
GHASP-instrument, GHaFAS
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Scanning Fabry-Perot Interferometer
gap between plates
Line intensity
??

• large field of view 1-10 arcmin
• high spectral resolution?? 0.22Å
• high orders n 100...1000
• small spectral range ? ? ?/n550 Å

? ?
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Scanning Fabry-Perot Interferometer in SAO
1982 CIGALE system from Marseille Observatory
(J. Boulesteix et al.) 1988 CIGALE with new
IPCS KVANT (SAO team V. Afanasiev, A.
Burenkov, S. Dodonov, S. Drabek, V. Vlasyuk)
1997 set a CCD instead IPCS 2000 multimode
focal reducer SCORPIO fast CCD 2Kx2K
(Moiseev, 2002 Afanasiev Moiseev, 2005) 2009
new Fabry-Perot etalon (IC Optical System
Ltd.) Observations in Ha, NII, SII emission
lines with resolution 0.4 A (20 km/s)
Data reduction
Observed cube
Scaled in wavelength
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HII vs. HI kinematics
GMRT(Begum et al, 2008)
Fabry-Perot interferometers 21 cm radio inrerferometers
ISM Ionized gas Neutral hydrogen
Spatial resolution 1-2 arcsec 10-50 arcsec
Velocity resolution 10-50 km/s 2-10 km/s
HI
Different spatial scales beam smoothing
difference in distribution of gas fractions
Ha
Direct comparison of HI and HII
spatial-resolved kinematics in dwarf galaxies
(bubles, outflow, envelopes of HII
regions) IC1613 (Lozinskaya et al, 2003) IC10
(Lozinskaya et al, 2008) NGC 2366 (van Eymeren et
al, 2008) NGC 4861 (van Eymeren et al, 2009)
6-m telescope, SCORPIO/FPI
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FPI observations of dIrr/BCDG
Individual objects I Zw 18 (3.6 m, CFHT)
Petrosian et al (1997) Mrk 86 (3.6 m, CFHT) Gil
de Paz et al (1997) NGC4449 (4.2 m, WHT)
Muñoz-Tuñón et al (1998) Samples 6 BVDGs (3.6
m, ESO) Östlin et al (1999) 23 dIRR in GHASP
survey (1.93-m,OHP) - Epinat et al (2008),
(however only 10 objects have good quality of
velocity fields)
Galaxies 6-m telescope proposal PI Puplications
IC10, IC1613, U6456 Lozinskaya Lozinskaya, et al (2003, 2006-2009)
KK12, DDO125, U8508 Begum
10 BCDGs Muñoz-Tuñón Martines-Delgado, et al. (2007)
10 low-metallicity BCDGs Pustilnik Pustilnik et al., submitted
10 dwarfs Khlypin
NGC 7468 Hagen-Thorn Shaliapina et al (2004)
Total velocity fields of 37 BCDG and dIrr
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Rotation or peculiar motions?
Östlin et al (1999) the optical velocity
fields of the BCGs are complex and appear
perturbed...''

• No regular circular rotation?
• all ionized gas motions connect with regions of
  ongoing starformation

VIIZw403
Lozinskaya et al. (2006)
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• H II kinematics in the region of ongoing
  starformation in the dIrr galaxy IC 1613 a
  complex of expanding shells
• re-estimation ages of the bubles
• comparision with SF models

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PV diagrams for ionized shells
R4
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v1
v1
v2
v2
R4
(Lozinskaya et al., 2003)
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Regular circular rotation
Major part of the sample (24/3765) has regular
velocity pattern that is described by the model
of circular rotation VmaxgtgtVres
Velocities-model
Velocities
Model
Ha image
Mrk 36 MB-14.9
UGC5423 MB-14.7
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UGC 993 Merging of two dwarf disks
GMRT HI data (courtesy to Chengalur Pustilnik)
titled-ring model
(Pustilnik et al., submitted)
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HS22361344 two disks major merger
SDSS
(Pustilnik, Moiseev Kniazev, MNRAS, submitted)
Velocities
Model of circular rotation
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NGC 7468 the circumnuclear polar disk
Bettoni et al. (1990)
H? velocity field
??- image
The velocity field shows a gaseous disk (rlt900
pc) whose rotation plane is almost
perpendicular to the main galactic plane. The
merging of a gas-rich dwarf galaxy seem to be
responsible for the formation of the polar disc
(Shaliapina et al. 2004)
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The polar-ring formation
Bournaud Combes (2003) 1) the merging scenario
proposed by Bekki (1997, 1998), this scenario
assumes a head-on collision between two
orthogonal spiral galaxies. 2) the accretion
scenario this scenario (e.g. Schweizer et al.
1983, Reshetnikov Sotnikova 1997) consists of
the accretion of gas from another galaxy by the
host.
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Mrk 33 (Haro 2) inner polar disk
SDSS
Inner disk (kinematics) PA171, i60 Outer
disk (isophotes) PA120, i48 Two solutions
for ?i 86 and 41
B-band (Cairos et al, 2001)
B-band (Cairos et al, 2001)
B-band (Cairos et al, 2001)
VLA 15'' beam (Bravo-Alfaro et al, 2004)
..a dwarf elliptical that has recently
captured gas in a close interaction or merger
with an initially gas-rich companion.''
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Mrk 370 outer HII regions on polar orbits
Ha image(Cairós et al, 2002)
Inner disk PA270, i40 Outer regions
PA15, i70 Two solutions for ?i 83 and 65
Tilted-rings models
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BCD galaxy Arp 212 (NGC 7625, III Zw 102)?
Arp (1966)
Ha-image
Moiseev (2008)
Inner disk (main body)
Outer filaments
6-m telescope, FPI
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Warped outer disk?
Tilted-ring model for outer disk
Orbits of the gaseous clouds
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Arp 212 HI distribution
HI VLA (Li et al., 1993)?
Precession of gas orbits in the triaxial
garvitational potential
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..Formation of the polar/warped gaseous disk
after accretion from gas-rich dwarf galaxy UGC
12549.. (Mosieev, 2008)
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Even in galaxies with strong starformation the
regular component dominates in the ionized gas
velocity fields (2/3 of all cases) An important
role of current/recent interactions and mergers
in the observed enhanced star formation in BCDG
(all objects in the sample of low-metallicity
dwarfs are of interacted/mergers) Gas on
polar/warped orbits (5/3714 of observed
sample)!
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Thank you!