Light Profiles and Pattern Speeds for Bars in Early- and Late-Type Galaxies

Elmegreen, Bruce G.; Elmegreen, D. M.; Chromey, F. R.; Hasselbacher, David A.; Bissell, Bradley A.

doi:10.1086/117957

Cited by 94 publications

(121 citation statements)

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“…In the bar/inter-bar contrast method of Elmegreen & Elmegreen (1985) and Elmegreen et al (1996), bar strength is parameterized as the ratio between peak surface brightness in the bar region and the minimum surface brightness in the inter-bar region. Elmegreen & Elmegreen (1985) and Elmegreen et al (1996) also characterize bar strength with the maximum amplitude of the m = 2 mode from Fourier decomposition. When ellipse fitting is applied, the maximum ellipticity of the bar, e bar , can be used to characterize bar strength (e.g.…”

Section: Bar Strengthmentioning

confidence: 99%

BULGEnANDB/TIN HIGH-MASS GALAXIES: CONSTRAINTS ON THE ORIGIN OF BULGES IN HIERARCHICAL MODELS

Weinzirl

Jogee

Khochfar

et al. 2009

ApJ

316

382

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We use the bulge Sérsic index n and bulge-to-total ratio (B/T ) to explore the fundamental question of how bulges form. We perform 2D bulge-disk-bar decomposition on H-band images of 143 bright, high mass (M ⋆ ≥ 1.0 × 10 10 M ⊙ ) low-to-moderately inclined (i < 70 • ) spirals. Our results are: (1) Our H-band bar fraction (∼ 58%) is consistent with that from ellipse fits. (5) We compare the results with predictions from a set of ΛCDM models. In the models, a high mass spiral can have a bulge with a present-day low B/T ≤ 0.2 only if it did not undergo a major merger since z ≤ 2. The predicted fraction (∼ 1.6%) of high mass spirals, which have undergone a major merger since z ≤ 4 and host a bulge with a present-day low B/T ≤ 0.2, is a factor of over thirty smaller than the observed fraction (∼ 66%) of high mass spirals with B/T ≤ 0.2. Thus, contrary to common perception, bulges built via major mergers since z ≤ 4 seriously fail to account for the bulges present in ∼ 66% of high mass spirals. Most of these present-day low B/T ≤ 0.2 bulges are likely to have been built by a combination of minor mergers and/or secular processes since z ≤ 4.

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Section: Bar Strengthmentioning

confidence: 99%

BULGEnANDB/TIN HIGH-MASS GALAXIES: CONSTRAINTS ON THE ORIGIN OF BULGES IN HIERARCHICAL MODELS

Weinzirl

Jogee

Khochfar

et al. 2009

ApJ

316

382

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“…Different methods are adopted to determine these quantities. In particular, the bar strength can be measured using the gravitational torque exerted by the bar (Block et al 2002;Buta et al 2005), the maximum ellipticity of the bar (Martin 1995;Jogee et al 1999;Knapen et al 2000;Laine et al 2002;Marinova & Jogee 2007;Barazza et al 2008), Fourier decomposition (Elmegreen et al 1996), and visual estimates of strength (Eskridge et al 2002). As described in Sect.…”

Section: The Properties Of the Barsmentioning

confidence: 99%

Frequency and properties of bars in cluster and field galaxies at intermediate redshifts

Barazza¹,

Jablonka

Desai

et al. 2009

A&A

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We present a study of large-scale bars in field and cluster environments out to redshifts of ∼0.8 using a final sample of 945 moderately inclined disk galaxies drawn from the EDisCS project. We characterize bars and their host galaxies and look for relations between the presence of a bar and the properties of the underlying disk. We investigate whether the fraction and properties of bars in clusters are different from their counterparts in the field. The properties of bars and disks are determined by ellipse fits to the surface brightness distribution of the galaxies using HST/ACS images in the F814W filter. The bar identification is based on quantitative criteria after highly inclined (>60 • ) systems have been excluded. The total optical bar fraction in the redshift range z = 0.4−0.8 (median z = 0.60), averaged over the entire sample, is 25% (20% for strong bars). For the cluster and field subsamples, we measure bar fractions of 24% and 29%, respectively. We find that bars in clusters are on average longer than in the field and preferentially found close to the cluster center, where the bar fraction is somewhat higher (∼31%) than at larger distances (∼18%). These findings however rely on a relatively small subsample and might be affected by small number statistics. In agreement with local studies, we find that disk-dominated galaxies have a higher optical bar fraction (∼45%) than bulge-dominated galaxies (∼15%). This result is based on Hubble types and effective radii and does not change with redshift. The latter finding implies that bar formation or dissolution is strongly connected to the emergence of the morphological structure of a disk and is typically accompanied by a transition in the Hubble type. The question whether internal or external factors are more important for bar formation and evolution cannot be answered definitely. On the one hand, the bar fraction and properties of cluster and field samples of disk galaxies are quite similar, indicating that internal processes are crucial for bar formation. On the other hand, we find evidence that cluster centers are favorable locations for bars, which suggests that the internal processes responsible for bar growth are supported by the typical interactions taking place in such environments.

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“…The isophotes were traced using the ellipse task in IRAF, which is based on the photometric technique developed by Jedrzejewski (1987). The bar-defining isophote was assumed to be where the position angle of the elliptical isophotes change direction and start tracing the disk of the galaxy (Elmegreen et al 1996;Laurikainen & Salo 2000). This isophote was used to determine the position angle and semimajor axis length of the bar.…”

Section: Bar Size and Ellipticitymentioning

confidence: 99%

“…All the profiles have a characteristic peak at the center due to the bulge and usually a flat portion that represents the bar. Such profiles have been used in previous studies to determine bar sizes and ellipticities (Elmegreen et al 1996;Regan & Elmegreen 1997). We have assumed that the bulge radius is the distance along the bar where the central peak appears to end and the bar profile becomes prominent.…”

Section: Bar Size and Ellipticitymentioning

confidence: 99%

Central Mass Concentration and Bar Dissolution in Nearby Spiral Galaxies

Das

Teuben

Vogel

et al. 2003

ApJ

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We use data from the BIMA Survey of Nearby Galaxies (SONG) to investigate the relationship between ellipticity and central mass concentration in barred spirals. Existing simulations predict that bar ellipticity decreases as inflowing mass driven by the bar accumulates in the central regions, ultimately destroying the bar. Using the ratio of the bulge mass to the mass within the bar radius as an estimate of the central mass concentration, we obtain dynamical mass estimates from SONG CO 1-0 rotation curve data. We find an inverse correlation between bar ellipticity and central mass concentration, consistent with simulations of bar dissolution.

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Light Profiles and Pattern Speeds for Bars in Early- and Late-Type Galaxies

Cited by 94 publications

References 0 publications

BULGEnANDB/TIN HIGH-MASS GALAXIES: CONSTRAINTS ON THE ORIGIN OF BULGES IN HIERARCHICAL MODELS

BULGEnANDB/TIN HIGH-MASS GALAXIES: CONSTRAINTS ON THE ORIGIN OF BULGES IN HIERARCHICAL MODELS

Frequency and properties of bars in cluster and field galaxies at intermediate redshifts

Central Mass Concentration and Bar Dissolution in Nearby Spiral Galaxies

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