arXiv subjects

C. Muñoz-Tuñón

Publications and source records attributed to C. Muñoz-Tuñón.

24 records · Page 2Linked to original sources

arXiv2005

The V-band luminosity function of galaxies in A2151

We present a wide field $V$-band imaging survey of approximately 1 deg$^2$ ($\sim7.2 h^{-2}_{75}$ Mpc$^{2}$) in the direction of the nearby cluster of galaxies Abell 2151 (the Hercules Cluster). The data are used to construct the luminosity function (LF) down to $M_V \approx -14.85$, thus allowing us to study the dwarf galaxy population in A2151 for the first time. The obtained global LF is well described by a Schechter function with best-fit parameters $α= -1.29^{+0.09}_{-0.08}$ and $M_V^* = -21.41^{+0.44}_{-0.41}$. The radial dependence of the LF was investigated, with the faint-end slope tending to be slightly steeper in the outermost regions and farther away than the virial radius. Given the presence of significant substructure within the cluster, we also analysed the LFs in three different regions. We find that the dwarf to giant ratio increases from the northern to the southern subcluster, and from low to high local density environments, although these variations are marginally significant (less than 2$σ$).

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arXiv2005

Photometric properties and origin of bulges in SB0 galaxies

We have derived the photometric parameters for the structural components of a sample of fourteen SB0 galaxies by applying a parametric photometric decomposition to their observed $I$-band surface brightness distribution. We find that SB0 bulges are similar to bulges of the early-type unbarred spirals, i.e. they have nearly exponential surface brightness profiles ($ =1.48\pm0.16$) and their effective radii are strongly coupled to the scale lengths of their surrounding discs ($ =0.20\pm0.01$). The photometric analysis alone does not allow us to differentiate SB0 bulges from unbarred S0 ones. However, three sample bulges have disc properties typical of pseudobulges. The bulges of NGC 1308 and NGC 4340 rotate faster than bulges of unbarred galaxies and models of isotropic oblate spheroids with equal ellipticity. The bulge of IC 874 has a velocity dispersion lower than expected from the Faber--Jackson correlation and the fundamental plane of the elliptical galaxies and S0 bulges. The remaining sample bulges are classical bulges, and are kinematically similar to lower-luminosity ellipticals. In particular, they follow the Faber--Jackson correlation, lie on the fundamental plane and those for which stellar kinematics are available rotate as fast as the bulges of unbarred galaxies.

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arXiv2004

The Luminosity Function of Galaxies in the Hercules Cluster

We have imaged $\sim$ 1 deg$^{2}$ in the V-band in the direction of the Hercules Cluster (Abell 2151). The data are used to compute for the first time the luminosity function (LF) of galaxies in the cluster down to the dwarf regime (M$_{lim}$ $\sim$ -13.85). The global LF is well described by a Schechter function (\cite{schechter76}) with best-fit parameters $α$ = -1.30 $\pm$ 0.06 and M$_V$$^*$ = -21.25 $\pm$ 0.25. The radial dependence of the LF has also been studied, finding that it turns out to be almost constant within the errors even further away than the virial radius. Given the presence of significant substructure within the cluster, we have analized the LFs in different regions. While two of the subclusters present LFs consistent with each other and with the global one, the southernmost one exhibits a somewhat steeper faint-end slope.

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arXiv2004

Environmental Effects in the Structural Parameters of Galaxies in the Coma Cluster

We have studied 116 bright galaxies from the Coma cluster brighter than $m_{r}=17$ mag. From a quantitative morphological analysis we find that the scales of the disks are smaller than those of field spiral galaxies. There is a correlation between the scale of the disks and the position of the galaxy in the cluster; no large disks are present near the center of the cluster or in high density environments. The structural parameters of the bulges are not affected by the environment. We have analyzed the distribution of blue and red objects in the cluster. For spirals there is a trend between color and position in the cluster. The bluest spiral galaxies are located at larger projected radii; they also show larger velocity dispersions than the red ones. The differences in the scale of the disks between cluster galaxies and local samples of isolated galaxies and the color distribution of the objects can be understood in terms of the harassment scenario.

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arXiv2002

The spatial distribution of the far-infrared emission in NGC 253

We study the far-infrared emission properties of the nearby starburst galaxy NGC 253 based on IRAS maps and an ISOPHOT map at 180 microns. Based on the analysis of the light profiles, we have been able to identify three main structural components: an unresolved nuclear component, an exponential disk, and a kiloparsec scale bar.In addition, we also found a ring structure at the end of the bar that is particularly conspicuous at 12 microns. The Spectral Energy Distribution (SED) of each morphological component has been modeled as thermal dust emission at different temperatures. The unresolved nuclear component is dominated by cold dust emission (T ~ 50 K), whereas the disk emission is dominated by very cold dust (T ~ 16 K) plus a contribution from cold dust (T ~ 55 K). The bar emission corresponds mainly to cold dust (T ~ 23 K) plus a warm component (T ~ 148 K). We detect an extension of the disk emission due to very cold dust, which contributes a large fraction (94%) of the total dust mass of the galaxy. The estimated total dust mass is 8.2 +/- 10^7 Msun.

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arXiv2000

Optical Surface Photometry of a Sample of Disk Galaxies. II Structural Components

This work presents the structural decomposition of a sample of 11 disk galaxies, which span a range of different morphological types. The U, B, V, R, and I photometric information given in Paper I (color and color-index images and luminosity, ellipticity, and position-angle profiles) has been used to decide what types of components form the galaxies before carrying out the decomposition. We find and model such components as bulges, disks, bars, lenses and rings.

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