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New polar ring galaxies catalogue.
·Alexei Moiseev(1), Ksenia Smirnova(2), Aleksandrina Smirnova Vladimir Reshetnikov(3) & Francoise Combes(4)
(1) Special Astrophysical Observatory RAS, Russia (2) Ural State University, Russia (3) St. Petersburg State University, Russia (4)Observatoire de Paris, LERMA & CNRS, France
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(1 )


A photographic atas of 157 polar ring galaxies, Whitmore et al (1990):
PRC-A (6 galaxies): Kinematically confirmed A-5 PRC-B ( 27 galaxies) Good candidates B-17 PRC-B ( 73 galaxies) Possible candidates C-43

PRC-D ( 51 galaxies) Related objects D-15

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Studying a role of merging and interactions in galaxy evolution (disc and bulge formation, starformation, etc.) · Implication for dark matter contents: M/L>20-50 · Probe to the 3D shapes of dark matter halo · "Cold" gas accretion for galaxies masses assembly?


Formation of polar rings: simulations
1) The major merging scenario:
- A head-on collision between two orthogonal spiral galaxies (Bekki, 1998; Bournaud & Combes, 2003)

2) The accretion scenario:
-Tidal accretion of the polar material from a gas-rich donor galaxy (Schweizer et al. 1983; Reshetnikov & Sotnikova 1997) - the disruption of a small companion on a polar orbit - accretion of gas infalling from extragalactic cosmic filaments (Maccio et al., 2006)

Bournaud & F. Combes (2003)


20 years looking in Polar Rings Catalogue...
see Combes (2005), Iodice et al. (2003), Sparke (2002) ... A host galaxy like S0 or E, the polar component is like spirals or irregular galaxies (gas-rich and bluer) Not only narrow annuli, but also extended disc-like rings Warped and inclined rings

Only 20 large-scale polar rings + 6 inner rings were kinematically confirmed from the Whitmore et al. list:
- HI maps (Cox et al; Sparke et al. ) - optical-long slit spectroscopy (Reshetnikov et al) - optical 3D spectroscopy (Spalyapina et al, Brosch et al)


SDSS-based Polar Ring Catalogue (=SPRC)

Results of original Galaxy Zoo project: - GalZoo ring galaxies internet-forum - Visual inspection of 41958 SDSS DR7 images preliminary selected using Galaxy Zoo simple classification from Lintott , et al (2011)

Moiseev et al (2011, MNRAS, 418, 244): 275 candidates 14 already have kinematic confirmation


The BEST Candidates (70) GOOD Candidates (115) RELATED Objects (53)

FACE ON Rings (37) New catalogue -- SPRC: 275 candidates ( 185 -- "the best" + "good")


SDSS-based Polar Ring Catalogue


SAO RAS 6-m telescope observations

In references: 5 confirmed polar rings (including SPRC-7 observed at the 6 m telescope

2010: 5 confirmed polar rings, 1 case of overlap 2011: + 4 confirmed polar rings


"The best" objects with known gas/stars kinematics


What is the true shape of dark matter halo?
Theory and simulations:
A flattening should be depend from the origin (Combes, 2005): Accretion: c/a<1 Merging: c/a1 Triaxial CDM halo: c/a=0.5-0.7

Observations:

T-F relation (Iodice flattened halo along Iodice et al (2009): constrains very flat

et al 2003; Reshetnikov 2004 ): polar plane new dynamical model for NGC4450A halo with c/a=0.3

Strongly tilted rings would survive preferentially in roundest halos:
NGC 2685 (Josza et a, 2009), NGC 3718 (Sparke et al, 2009), NGC 4753 (Steiman-Cameron, 1993)
Iodice et al (2009)

We need more spatial resolved 2D kinematics + detailed modeling of the 3D gravitational potential distribution

22 kpc


3D dark halo shape: simulations vs. observations:

1) Slightly triaxial halo (c/b=0.95 a/b=1.1 2) Evolved spiral structure in the polar ring (Khoperskov et al, poster on the SpS 3)


New examples of extended massive rings

h a

Discs rather than rings... How did they acquire a mass equal with their osts? Fast rotation of central galaxies contradicts with major merging scenario

NGC 4650A ­ a local analogue (Spavone+ 2010)

Cold gas accretion along misalignment filaments?

Hoag object (my talk on SpS 3)


Gas accretion from cosmic filaments
Macci et al (2006): gas infalling from cosmic filaments, with inclined angular momentum Dekel et al (2009) simulations NGC 4650A

Brook et al (2008) : Simulated object similar with NGC 4650A Iodice et al (2010): low metallicity (Z=0.2 Zsun) in the polar disk of NGC 4650 implies a cold accretion scenario?
Spavone's talks on SpS 4


Molecular gas observations
21 galaxies observed 12 Candidate PRG P13 P15 P17 P24 P29 P31 P42 P47 P48 P52 P56 P61 9 Confirmed PRG PC7 PC10 PC14 PC33 PC67 PC69 PC260 PC39 PC60

Double-horn profiles Rotating disks Typical masses 2 109 Mo

IRAM-30m


Molecular gas observations
CO(1-0) and CO(2-1) ·Simultaneously observed with IRAM-30m 24% detection rate ·About the same as in ATLAS3D nearby early-types galaxies ·(22%, Young et al, 2011) · · · CO(2-1)/CO(1-0) ratio typical of dense galaxy diss or nuclei


Conclusion
Sloan-based Polar Rings Catalogue contains 275 galaxies. It significantly (in 3 times) increases a number of genuen PRG candidates and may serve as a good basis both for the further detailed study of individual galaxies, and for the statistical analysis of PRGs as a separate class of objects. 14 SPRC galaxies already have a kinematic confirmation The most interesting items related with further studying of SPRC: - 3D dark halo shape - Statistic of an external gas accretion, including a cold accretion along filaments

The deep HI observations are stronlgly needed!


Thank you for your attention!