A slow bar in a dark matter dominated galaxy

Chemin, L.; Hernandez, O.

doi:10.1051/0004-6361/200912019

Cited by 33 publications

(58 citation statements)

References 29 publications

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“…The TW method was also applied to gas tracers, such as CO (Zimmer et al 2004;Rand & Wallin 2004) or Hα (Hernandez et al 2005;Emsellem et al 2006;Fathi et al 2007Fathi et al , 2009Chemin & Hernandez 2009;Gabbasov et al 2009). …”

Section: Theoretical Basis Of the Tw Methodsmentioning

confidence: 99%

Bar pattern speeds in CALIFA galaxies

Aguerri

Méndez-Abreu

Falcón-Barroso

et al. 2015

A&A

113

189

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Context. The bar pattern speed (Ω b ) is defined as the rotational frequency of the bar, and it determines the bar dynamics. Several methods have been proposed for measuring Ω b . The non-parametric method proposed by Tremaine & Weinberg (1984, ApJ, 282, L5; TW) and based on stellar kinematics is the most accurate. This method has been applied so far to 17 galaxies, most of them SB0 and SBa types. Aims. We have applied the TW method to a new sample of 15 strong and bright barred galaxies, spanning a wide range of morphological types from SB0 to SBbc. Combining our analysis with previous studies, we investigate 32 barred galaxies with their pattern speed measured by the TW method. The resulting total sample of barred galaxies allows us to study the dependence of Ω b on galaxy properties, such as the Hubble type. Methods. We measured Ω b using the TW method on the stellar velocity maps provided by the integral-field spectroscopy data from the CALIFA survey. Integral-field data solve the problems that long-slit data present when applying the TW method, resulting in the determination of more accurate Ω b . In addition, we have also derived the ratio R of the corotation radius to the bar length of the galaxies. According to this parameter, bars can be classified as fast (R < 1.4) and slow (R > 1.4). Results. For all the galaxies, R is compatible within the errors with fast bars. We cannot rule out (at 95% level) the fast bar solution for any galaxy. We have not observed any significant trend between R and the galaxy morphological type. Conclusions. Our results indicate that independent of the Hubble type, bars have been formed and then evolve as fast rotators. This observational result will constrain the scenarios of formation and evolution of bars proposed by numerical simulations.

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Section: Theoretical Basis Of the Tw Methodsmentioning

confidence: 99%

Bar pattern speeds in CALIFA galaxies

Aguerri

Méndez-Abreu

Falcón-Barroso

et al. 2015

A&A

113

189

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“…The bar in UGC 628 is itself also extremely unusual in that it is a slow bar, meaning that bar pattern speed is slow enough that the corotation radius is more than 1.4 times the semi-bar length (Chemin & Hernandez 2009). This is one of only three slow bars known, the others being a stellar bar in the dwarf irregular galaxy NGC 3741 (Banerjee et al 2013) and a purely gaseous slow bar in the dwarf irregular galaxy NGC 2915 (Bureau et al 1999).…”

Section: Target Selection and Backgroundmentioning

confidence: 99%

The distribution of star formation and metals in the low surface brightness galaxy UGC 628

Young¹,

Naray²,

Wang³

2015

Mon. Not. R. Astron. Soc.

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We introduce the MUSCEL Program (MUltiwavelength observations of the Structure, Chemistry and Evolution of LSB galaxies), a project aimed at determining the starformation histories of low surface brightness galaxies. MUSCEL utilizes ground-based optical spectra and space-based UV and IR photometry to fully constrain the starformation histories of our targets with the aim of shedding light on the processes that led low surface brightness galaxies down a different evolutionary path from that followed by high surface brightness galaxies, such as our Milky Way. Here we present the spatially-resolved optical spectra of UGC 628, observed with the VIRUS-P IFU at the 2.7-m Harlen J. Smith Telescope at the McDonald Observatory, and utilize emission-line diagnostics to determine the rate and distribution of star formation as well as the gas-phase metallicity and metallicity gradient. We find highly clustered star formation throughout UGC 628, excluding the core regions, and a log(O/H) metallicity around −4.2, with more metal rich regions near the edges of the galactic disk. Based on the emission-line diagnostics alone, the current mode of star formation, slow and concentrated in the outer disk, appears to have dominated for quite some time, although there are clear signs of a much older stellar population formed in a more standard inside-out fashion.

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“…Inner structures in real galaxies produce noticeable features in the ellipticity ( ) and PA profiles of the central isophotes of the host galaxies Falcón-Barroso et al 2004;Chemin & Hernandez 2009). In the right panels of Figs.…”

Section: Ellipticity and Position Angle Profiles Of The Remnantsmentioning

confidence: 99%

A minor merger origin for stellar inner discs and rings in spiral galaxies

Eliche‐Moral

González-García

Balcells

et al. 2011

A&A

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Context. Observations have shown that inner discs and rings (IDs and IRs) are not preferably found in barred galaxies, which indicates that their formation may differ from that described by the traditional bar-origin scenario in many cases. In contrast, the role of minor mergers in producing these inner components (ICs), while often invoked, is still poorly understood. Aims. We investigate the capability of minor mergers to trigger the formation of IDs and IRs in spiral galaxies through collisionless N-body simulations. Methods. We run a battery of minor merger simulations in which both primary and secondary galaxies are modelled as disc-bulgehalo galaxies with realistic density ratios. Different orbits and mass ratios are considered, as well as two different models for the primary galaxy (a Sab or Sc). We then perform a detailed analysis of the morphology, structure, and kinematics of the ICs resulting from the minor merger. Results. All the simulated minor mergers develop thin ICs out of satellite material, supported by rotation. A wide morphological zoo of ICs are obtained (including IDs, IRs, pseudo-rings, nested IDs, spiral patterns, and combinations of them), but all have structural and kinematical properties similar to those observed. The sizes of the resulting ICs are comparable to those observed in real galaxies with the adequate scaling. The existence of the resulting ICs can be deduced from the features that they imprint in the isophotal profiles and kinemetric maps of the final remnant, as in many real galaxies. Weak transitory oval distortions appear in the remnant centre in many cases, but none of them develops a noticeable bar. The realistic density ratios used in the present models ensure that the satellites experience more efficient orbital circularization and disruption than in previous studies. Combined with the disc resonances induced by the encounter, these processes produce highly aligned co-and counter-rotating ICs at the remnant centre. Conclusions. Minor mergers are an efficient mechanism for forming rotationally-supported stellar ICs in spiral galaxies, without requiring either strong dissipation or the development of noticeable bars. The present models indicate that minor mergers can account for the existence of pure-stellar old ICs in unbarred galaxies, and suggest that their role must have been crucial in the formation of ICs and much more complex than just bar triggering.

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A slow bar in a dark matter dominated galaxy

Cited by 33 publications

References 29 publications

Bar pattern speeds in CALIFA galaxies

Bar pattern speeds in CALIFA galaxies

The distribution of star formation and metals in the low surface brightness galaxy UGC 628

A minor merger origin for stellar inner discs and rings in spiral galaxies

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