Polar Ring Galaxies and the Tully‐Fisher Relation: Implications for the Dark Halo Shape

Iodice, E.; Arnaboldi, M.; Bournaud, F.; Combes, F.; Sparke, Linda S.; Driel, W. van; Capaccioli, M.

doi:10.1086/346107

Cited by 63 publications

(98 citation statements)

References 58 publications

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“…The dark-to-visible mass ratio in PRGs is again not larger than in spiral galaxies. Iodice et al (2003) have shown that polar ring velocities are abnormally large, when compared to the Tully-Fisher relation for spiral galaxies. The dark halo could then be either flattened along the polar ring, or spheroidal and very massive: the dark-to-visible mass ratio inside the optical radius would be as large as 3.5.…”

Section: Dark Matter Around Polar Ring Galaxiesmentioning

confidence: 95%

Formation of polar ring galaxies

Bournaud

Combes

2003

A&A

Self Cite

156

196

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Abstract. Polar ring galaxies are peculiar systems in which a gas-rich, nearly polar ring surrounds an early-type or elliptical host galaxy. Two formation scenarios for these objects have been proposed: they are thought to form either in major galaxy mergers or by tidal accretion of the polar material from a gas rich donor galaxy. Both scenarios are studied through N-body simulations including gas dynamics and star formation. Constraints on physical parameters are drawn out, in order to determine which scenario is the most likely to occur. Polar ring galaxies from each scenario are compared with observations and we discuss whether the accretion scenario and the merging scenario account for observational properties of polar ring galaxies. The conclusion of this study is that the accretion scenario is both the most likely and the most supported by observations. Even if the merging scenario is rather robust, most polar ring galaxies are shown to be the result of tidal gas accretion events.

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Section: Dark Matter Around Polar Ring Galaxiesmentioning

confidence: 95%

Formation of polar ring galaxies

Bournaud

Combes

2003

A&A

Self Cite

156

196

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“…NGC 6822 can therefore be considered to be a polar ring galaxy (PRG). Investigators of PRGs have found that almost all of these systems exhibit evidence of recent formation, possibly within the past 2 Gyr (Whitmore et al 1990;Iodice et al 2003). If this is also the case of NGC 6822, we need to identify the interaction that may have triggered a burst of star formation.…”

Section: Age Distributionmentioning

confidence: 99%

Long period variable survey in NGC 6822

Battinelli

Demers

2010

A&A

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Context. The star-formation history of the intermediate-age population of the Local Group dwarf irregular galaxy NGC 6822 may have been influenced by the often discussed interaction with its HI cloud that might have produced the present polar-ring structure. Aims. We investigate the period distribution of the Mira variables in the central region and the spheroid of NGC 6822. Methods. We use the new wide-field near-infrared imager CPAPIR to acquire K s images of a 32 × 32 area, which includes a good part of the eastern spheroid of NGC 6822. Results. Periods could be determined for 45 cyclic and semi-regular variables brighter than K = 17. The vast majority of the variables have ages between 1 and 3 Gyr. Conclusions. The period distribution of the long period variables may reflect the proposed interaction with the HI cloud that produces the polar ring.

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“…On longer timescales, the polar ring can become warped or unstable. Moreover, some observations [29] suggest that the velocity field of some polar ring galaxies is consistent with a flattened dark matter halo, along the plane of the polar ring. Our simulations show that stable polar rings form also if the dark matter halo is spherical.…”

Section: Gas Ringsmentioning

confidence: 98%

Back to the Green Valley: How to Rejuvenate an S0 Galaxy through Minor Mergers

Mapelli

2015

Galaxies

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About half of the S0 galaxies in the nearby Universe show signatures of recent or ongoing star formation. Whether these S0 galaxies were rejuvenated by the accretion of fresh gas is still controversial. We study minor mergers of a gas-rich dwarf galaxy with an S0 galaxy, by means of N-body smoothed-particle hydrodynamics simulations. We find that minor mergers trigger episodes of star formation in the S0 galaxy, lasting for ∼10 Gyr. One of the most important fingerprints of the merger is the formation of a gas ring in the S0 galaxy. The ring is reminiscent of the orbit of the satellite galaxy, and its lifetime depends on the merger properties: polar and counter-rotating satellite galaxies induce the formation of long-lived smooth gas rings.

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Polar Ring Galaxies and the Tully‐Fisher Relation: Implications for the Dark Halo Shape

Cited by 63 publications

References 58 publications

Formation of polar ring galaxies

Formation of polar ring galaxies

Long period variable survey in NGC 6822

Back to the Green Valley: How to Rejuvenate an S0 Galaxy through Minor Mergers

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