Optical surface photometry of a sample of disk galaxies

Prieto, M.; Aguerri, J. A. L.; Varela, A. M.; Muñoz–Tuñón, C.

doi:10.1051/0004-6361:20000426

Cited by 83 publications

(120 citation statements)

References 33 publications

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“…This can be achieved by performing a photometric decomposition of the galaxy surfacebrightness distribution. The galaxy light is usually modeled as the sum of the contributions of the different galactic components, i.e., bulge and disk, and eventually lenses, bars, spiral arms, and rings (Prieto et al 2001;Aguerri et al 2005). A number of two-dimensional parametric decomposition techniques have been developed to achieve this aim (e.g., Simard 1998;Khosroshahi et al 2000;Peng et al 2002;de Souza et al 2004;Laurikainen et al 2005;Pignatelli et al 2006;Méndez-Abreu et al 2008).…”

Section: Intrinsic Shape Of Disk Galaxiesmentioning

confidence: 99%

Structural properties of disk galaxies

Méndez-Abreu

Simonneau

Aguerri

et al. 2010

A&A

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Context. Knowledge of the intrinsic shapes of galaxy components provides crucial information when constraining phenomena driving their formation and evolution. Aims. We analize the structural parameters of a magnitude-limited sample of 148 unbarred S0-Sb galaxies to derive the intrinsic shape of their bulges. Methods. We developed a new method to derive the intrinsic shapes of bulges based on geometrical relationships between the apparent and intrinsic shapes of bulges and disks. Bulges were assumed to be triaxial ellipsoids sharing the same center and polar axis of their surrounding disks. Disks were assumed to be circular, infinitesimally thin, and to lie on the equatorial plane of bulges. The equatorial ellipticity and intrinsic flattening of bulges were obtained from the length of the apparent major and minor semi-axes of the bulge, the twist angle between the apparent major axis of the bulge and the galaxy line of nodes, and the galaxy inclination. Results. We find that the intrinsic shape is well constrained for a subsample of 115 bulges with favorable viewing angles. A large fraction of them are characterized by an elliptical section (B/A < 0.9). This fraction is 33%, 55%, and 43% if using their maximum, mean, or median equatorial ellipticity, respectively. Most are flattened along their polar axis (C < (A + B)/2). Only 18% of the observed bulges have a probability >50% and none has a probability >90% of being elongated along the polar axis. The distribution of triaxiality is strongly bimodal. This bimodality is driven by bulges with Sérsic index n > 2, or equivalently, by the bulges of galaxies with a bulge-to-total ratio B/T > 0.3. Bulges with n ≤ 2 and with B/T ≤ 0.3 follow a similar distribution, which differs from that of bulges with n > 2 and B/T > 0.3. In particular, bulges with n ≤ 2 and B/T ≤ 0.3 exhibit a larger fraction of oblate axisymmetric (or nearly axisymmetric) bulges, a smaller fraction of triaxial bulges, and fewer prolate axisymmetric (or nearly axisymmetric) bulges with respect to bulges with n > 2 and with B/T > 0.3, respectively. No correlation is found between the intrinsic shape and either the luminosity or velocity dispersion of bulges. Conclusions. According to predictions of the numerical simulations of bulge formation, bulges with n ≤ 2, which show a high fraction of oblate axisymmetric (or nearly axisymmetric) shapes and have B/T ≤ 0.3, may be the result of dissipational minor mergers. Both major dissipational and dissipationless mergers seem to be required to explain the variety of shapes found for bulges with n > 2 and B/T > 0.3.

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Section: Intrinsic Shape Of Disk Galaxiesmentioning

confidence: 99%

Structural properties of disk galaxies

Méndez-Abreu

Simonneau

Aguerri

et al. 2010

A&A

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“…Secondly, for systems with small bulges MacArthur et al (2003) showed that results from one-dimensional photometry are equivalent to those derived from two-dimensional fits (as required by this work). The resulting sample is comprised of 61 galaxies taken from Möllenhoff (2004), MacArthur et al (2003), Prieto et al (2001) and Pompei & Natali (1997). Since MacArthur et al had measurements in B V R H, their R band scalelengths were converted to I band scalelengths by multiplying them by a factor of 0.981.…”

Section: Application To Local Universe Disk Galaxiesmentioning

confidence: 99%

Modelling the spectral energy distribution of galaxies

Möllenhoff¹,

Popescu

Tuffs

2006

A&A

123

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We present corrections for the change in the apparent scalelengths, central surface brightnesses and axis ratios due to the presence of dust in pure disk galaxies, as a function of inclination, central face-on opacity in the B-band (τ f B ) and wavelength. The correction factors were derived from simulated images of disk galaxies created using geometries for stars and dust which can reproduce the entire spectral energy distribution from the ultraviolet (UV) to the Far-infrared (FIR)/submillimeter (submm) and can also account for the observed surface-brightness distributions in both the optical/Near-infrared and FIR/submm. We found that dust can significantly affect both the scalelength and central surface brightness, inducing variations in the apparent to intrinsic quantities of up to 50% in scalelength and up to 1.5 mag in central surface brightness. We also identified some astrophysical effects for which, although the absolute effect of dust is non-negligible, the predicted variation over a likely range in opacity is relatively small, such that an exact knowledge of opacity is not needed. Thus, for a galaxy at a typical inclination of 37• and having any τ f B > 2, the effect of dust is to increase the scalelength in B relative to that in I by a factor of 1.12 ± 0.02 and to change the B − I central colour by 0.36 ± 0.05 mag. Finally we use the model to analyse the observed scalelength ratios between B and I for a sample of disk-dominated spiral galaxies, finding that the tendency for apparent scalelength to increase with decreasing wavelength is primarily due to the effects of dust.

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“…In this context, the bulge is photometrically defined as the extra component dominating the galaxy light above the surfaceluca.costantin@studenti.unipd.it brightness profile of the disk extrapolated in the inner regions of the galaxy. The bulge surface brightness is usually fitted with a Sérsic law spanning a large range of profile shapes, whereas the disk surface brightness is usually fitted with an exponential law (Andredakis 1998;Prieto et al 2001;Aguerri et al 2005;Méndez-Abreu et al 2017). …”

Section: Introductionmentioning

confidence: 99%

No evidence for small disk-like bulges in a sample of late-type spirals

Costantin

Méndez-Abreu

Corsini

et al. 2017

A&A

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Context. About 20% of low-redshift galaxies are late-type spirals with a small or no bulge component. Although they are the simplest disk galaxies in terms of structure and dynamics, the role of the different physical processes driving their formation and evolution is not yet fully understood. Aims. We investigated whether small bulges of late-type spirals follow the same scaling relations traced by ellipticals and large bulges and if they are disk-like or classical bulges. Methods. We derived the photometric and kinematic properties of 9 nearby late-type spirals. To this aim, we analyzed the surfacebrightness distribution from the i-band images of the Sloan Digital Sky Survey and obtained the structural parameters of the galaxies from a two-dimensional photometric decomposition. We found a bulge component in 7 galaxies of the sample, while the remaining 2 resulted to be pure disk galaxies. We measured the line-of-sight stellar velocity distribution within the bulge effective radius from the long-slit spectra taken with high spectral resolution at the Telescopio Nazionale Galileo. We used the photometric and kinematic properties of the sample bulges to study their location in the Fundamental Plane, Kormendy, and Faber-Jackson relations defined for ellipticals and large bulges. Results. We found that our sample bulges satisfy some of the photometric and kinematic prescriptions for being considered disk-like bulges such as small sizes and masses with nearly exponential light profiles, small bulge-to-total luminosity ratios, low stellar velocity dispersions, and ongoing star formation. However, each of them follows the same scaling relations of ellipticals, massive bulges, and compact early-type galaxies so they cannot be classified as disk-like systems. Conclusions. We found a single population of galaxy spheroids that follow the same scaling relations, where the mass seems to lead to a smooth transition in the photometric and kinematic properties from less massive bulges to more massive bulges and ellipticals.

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Optical surface photometry of a sample of disk galaxies

Cited by 83 publications

References 33 publications

Structural properties of disk galaxies

Structural properties of disk galaxies

Modelling the spectral energy distribution of galaxies

No evidence for small disk-like bulges in a sample of late-type spirals

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