J. C. Muñoz-Mateos

University of Santiago, Chile, CiudadSantiago, Santiago Metropolitan, Chile

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Publications (50)153.33 Total impact

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    ABSTRACT: Using 3.6 and 4.5$\mu$m images of 73 late-type, edge-on galaxies from the S$^4$G survey, we compare the richness of the globular cluster populations of these galaxies to those of early type galaxies that we measured previously. In general, the galaxies presented here fill in the distribution for galaxies with lower stellar mass, M$_*$, specifically $\log({\rm M}_*/{\rm M}_\odot) < 10$, overlap the results for early-type galaxies of similar masses, and, by doing so, strengthen the case for a dependence of the number of globular clusters per $10^9\ {\rm M}_\odot$ of galaxy stellar mass, T$_{\rm N}$, on M$_*$. For $8.5 < \log ({\rm M}_*/{\rm M}_\odot) < 10.5$ we find the relationship can be satisfactorily described as T$_{\rm N} = ({\rm M}_*/10^{6.7})^{-0.56}$ when M$_*$ is expressed in solar masses. The functional form of the relationship is only weakly constrained and extrapolation outside this range is not advised. Our late-type galaxies, in contrast to our early-types, do not show the tendency for low mass galaxies to split into two T$_{\rm N}$ families. Using these results and a galaxy stellar mass function from the literature, we calculate that in a volume limited, local Universe sample, clusters are most likely to be found around fairly massive galaxies (M$_* \sim 10^{10.8}$ M$_\odot$) and present a fitting function for the volume number density of clusters as a function of parent galaxy stellar mass. We find no correlation between T$_{\rm N}$ and large-scale environment, but do find a tendency for galaxies of fixed M$_*$ to have larger T$_{\rm N}$ if they have converted a larger proportion of their baryons into stars.
    No preview · Article · Nov 2015
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    ABSTRACT: The Star Formation Rate (SFR) is one of the main parameters used to analyze the evolution of galaxies through time. The need for recovering the light reprocessed by dust commonly requires the use of low spatial resolution far-infrared data. Recombination-line luminosities provide an alternative, although uncertain dust-extinction corrections based on narrow-band imaging or long-slit spectroscopy have traditionally posed a limit to their applicability. Integral Field Spectroscopy (IFS) is clearly the way to overcome such limitation. We obtain integrated H{\alpha}, ultraviolet (UV) and infrared (IR)-based SFR measurements for 272 galaxies from the CALIFA survey at 0.005 < z < 0.03 using single-band and hybrid tracers. We provide updated calibrations, both global and split by properties (including stellar mass and morphological type), referred to H{\alpha}. The extinction-corrected H{\alpha} luminosity agrees with the updated hybrid SFR estimators based on either UV or H{\alpha} plus IR luminosity over the full range of SFRs (0.03-20 M$_{\odot}$ yr$^{-1}$). The coefficient that weights the amount of energy produced by newly-born stars that is reprocessed by dust on the hybrid tracers, a$_{IR}$, shows a large dispersion. However, it does not became increasingly small at high attenuations, as expected if significant highly-obscured H$\alpha$ emission would be missed. Lenticulars, early-type spirals and type-2 AGN host galaxies show smaller coefficients due to the contribution of optical photons and AGN to dust heating. In the Local Universe the H{\alpha} luminosity derived from IFS observations can be used to measure SFR, at least in statistically-significant, optically-selected galaxy samples. The analysis of the SFR calibrations by galaxies properties could be potentially used by other works to study the impact of different selection criteria in the SFR values derived.
    Full-text · Article · Jul 2015 · Astronomy and Astrophysics
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    ABSTRACT: The mid-infrared is an optimal window to trace stellar mass in nearby galaxies and the 3.6 mm IRAC band has been exploited to this effect, but such mass estimates can be biased by dust emission. We present our pipeline to reveal the old stellar flux at 3.6 μm and obtain stellar mass maps for more than 1600 galaxies available from the Spitzer Survey of Stellar Structure in Galaxies (S4G). This survey consists of images in two infrared bands (3.6 and 4.5 μm), and we use the Independent Component Analysis (ICA) method presented in Meidt et al. to separate the dominant light from old stars and the dust emission that can significantly contribute to the observed 3.6 mm flux. We exclude from our ICA analysis galaxies with low signal-to-noise ratio (S/N < 10) and those with original [3.6][4.5] colors compatible with an old stellar population, indicative of little dust emission (mostly early Hubble types, which can directly provide good mass maps). For the remaining 1251 galaxies to which ICA was successfully applied, we find that as much as 10%30% of the total light at 3.6 μm typically originates from dust, and locally it can reach even higher values. This contamination fraction shows a correlation with specific star formation rates, confirming that the dust emission that we detect is related to star formation. Additionally, we have used our large sample of mass estimates to calibrate a relationship of effective mass-to-light ratio (M/L) as a function of observed [3.6][4.5] color: log(M/L) = -0.339(±0.057) × ([3.6]-[4.5]) - 0.336(±0.002). Our final pipeline products have been made public through IRSA, providing the astronomical community with an unprecedentedly large set of stellar mass maps ready to use for scientific applications. © 2015. The American Astronomical Society. All rights reserved.
    Full-text · Article · Jul 2015 · The Astrophysical Journal Supplement Series
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    ABSTRACT: The Spitzer Survey of Stellar Structure in Galaxies (S4G) is a volume, magnitude, and size-limited survey of 2352 nearby galaxies with deep imaging at 3.6 and 4.5um. In this paper we describe our surface photometry pipeline and showcase the associated data products that we have released to the community. We also identify the physical mechanisms leading to different levels of central stellar mass concentration for galaxies with the same total stellar mass. Finally, we derive the local stellar mass-size relation at 3.6um for galaxies of different morphologies. Our radial profiles reach stellar mass surface densities below 1 Msun pc-2. Given the negligible impact of dust and the almost constant mass-to-light ratio at these wavelengths, these profiles constitute an accurate inventory of the radial distribution of stellar mass in nearby galaxies. From these profiles we have also derived global properties such as asymptotic magnitudes (and the corresponding stellar masses), isophotal sizes and shapes, and concentration indices. These and other data products from our various pipelines (science-ready mosaics, object masks, 2D image decompositions, and stellar mass maps), can be publicly accessed at IRSA (http://irsa.ipac.caltech.edu/data/SPITZER/S4G/).
    Full-text · Article · May 2015 · The Astrophysical Journal Supplement Series
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    Gabriele Pezzulli · Filippo Fraternali · Samuel Boissier · Juan Carlos Muñoz-Mateos
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    ABSTRACT: We present a new and simple method to measure the instantaneous mass and radial growth rates of the stellar discs of spiral galaxies, based on their star formation rate surface density (SFRD) profiles. Under the hypothesis that discs are exponential with time-varying scalelengths, we derive a universal theoretical profile for the SFRD, with a linear dependence on two parameters: the specific mass growth rate $\nu_\textrm{M} \equiv \dot{M_\star}/M_\star$ and the specific radial growth rate $\nu_\textrm{R} \equiv \dot{R}_\star/R_\star$ of the disc. We test our theory on a sample of 35 nearby spiral galaxies, for which we derive a measurement of $\nu_\textrm{M}$ and $\nu_\textrm{R}$. 32/35 galaxies show the signature of ongoing inside-out growth ($\nu_\textrm{R} > 0$). The typical derived e-folding timescales for mass and radial growth in our sample are ~ 10 Gyr and ~ 30 Gyr, respectively, with some systematic uncertainties. More massive discs have a larger scatter in $\nu_\textrm{M}$ and $\nu_\textrm{R}$, biased towards a slower growth, both in mass and size. We find a linear relation between the two growth rates, indicating that our galaxy discs grow in size at ~ 0.35 times the rate at which they grow in mass; this ratio is largely unaffected by systematics. Our results are in very good agreement with theoretical expectations if known scaling relations of disc galaxies are not evolving with time.
    Preview · Article · May 2015 · Monthly Notices of the Royal Astronomical Society
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    ABSTRACT: We present a kinematical study of 29 spiral galaxies included in the Spitzer Survey of Stellar Structure in Galaxies, using Halpha Fabry-Perot data obtained with the Galaxy Halpha Fabry-Perot System instrument at the William Herschel Telescope in La Palma, complemented with images in the R-band and in Halpha. The primary goal is to study the evolution and properties of the main structural components of galaxies through the kinematical analysis of the FP data, complemented with studies of morphology, star formation and mass distribution. In this paper we describe how the FP data have been obtained, processed and analysed. We present the resulting moment maps, rotation curves, velocity model maps and residual maps. Images are available in FITS format through the NASA/IPAC Extragalactic Database and the Centre de Donn\'ees Stellaires. With these data products we study the non-circular motions, in particular those found along the bars and spiral arms. The data indicate that the amplitude of the non-circular motions created by the bar does not correlate with the bar strength indicators. The amplitude of those non-circular motions in the spiral arms does not correlate with either arm class or star formation rate along the spiral arms. This implies that the presence and the magnitude of the streaming motions in the arms is a local phenomenon.
    Full-text · Article · Apr 2015 · Monthly Notices of the Royal Astronomical Society
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    ABSTRACT: Using 3.6$\mu$m images of 97 early-type galaxies, we develop and verify methodology to measure globular cluster populations from the S$^4$G survey images. We find that 1) the ratio, T$_{\rm N}$, of the number of clusters, N$_{\rm CL}$, to parent galaxy stellar mass, M$_*$, rises weakly with M$_*$ for early-type galaxies with M$_* > 10^{10}$ M$_\odot$ when we calculate galaxy masses using a universal stellar initial mass function (IMF), but that the dependence of T$_{\rm N}$ on M$_*$ is removed entirely once we correct for the recently uncovered systematic variation of IMF with M$_*$, and 2) for M$_* < 10^{10}$ M$_\odot$ there is no trend between N$_{\rm CL}$ and M$_*$, the scatter in T$_{\rm N}$ is significantly larger (approaching 2 orders of magnitude), and there is evidence to support a previous, independent suggestion of two families of galaxies. The behavior of N$_{\rm CL}$ in the lower mass systems is more difficult to measure because these systems are inherently cluster poor, but our results may add to previous evidence that large variations in cluster formation and destruction efficiencies are to be found among low mass galaxies. The average fraction of stellar mass in clusters is $\sim$ 0.0014 for M$_* > 10^{10}$ M$_\odot$ and can be as large as $\sim 0.02$ for less massive galaxies. These are the first results from the S$^4$G sample of galaxies, and will be enhanced by the sample of early-type galaxies now being added to S$^4$G and complemented by the study of later type galaxies within S$^4$G.
    Full-text · Article · Nov 2014 · The Astrophysical Journal
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    ABSTRACT: The mid-infrared is an optimal window to trace stellar mass in nearby galaxies and the 3.6 micron IRAC band has been exploited to this effect, but such mass estimates can be biased by dust emission. We present our pipeline to reveal the old stellar flux at 3.6 micron and obtain stellar mass maps for more than 1600 galaxies available from the Spitzer Survey of Stellar Structure in Galaxies (S4G). This survey consists of images in two infrared bands (3.6 and 4.5 micron), and we use the Independent Component Analysis (ICA) method presented in Meidt et al. (2012) to separate the dominant light from old stars and the dust emission that can significantly contribute to the observed 3.6 micron flux. We exclude from our ICA analysis galaxies with low signal-to-noise (S/N < 10) and those with original [3.6]-[4.5] colors compatible with an old stellar population, indicative of little dust emission (mostly early Hubble types, which can directly provide good mass maps). For the remaining 1251 galaxies to which ICA was successfully applied, we find that as much as 10-30% of the total light at 3.6 micron typically originates from dust, and locally it can reach even higher values. This contamination fraction shows a correlation with specific star formation rates, confirming that the dust emission that we detect is related to star formation. Additionally, we have used our large sample of mass estimates to calibrate a relationship of effective M/L as a function of observed [3.6]-[4.5] color: log(M/L)=-0.339 (+/- 0.057) x ([3.6]-[4.5]) -0.336 (+/-0.002). Our final pipeline products will be made public through IRSA, providing the astronomical community with an unprecedentedly large set of stellar mass maps ready to use for scientific applications.
    Full-text · Article · Sep 2014
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    ABSTRACT: Physical conditions of the interstellar medium in galaxies are closely linked to the ambient radiation field and the heating of dust grains. In order to characterize dust properties in galaxies over a wide range of physical conditions, we present here the radial surface brightness profiles of the entire sample of 61 galaxies from Key Insights into Nearby Galaxies: Far-Infrared Survey with Herschel (KINGFISH). The main goal of our work is the characterization of the grain emissivities, dust temperatures, and interstellar radiation fields responsible for heating the dust. After fitting the dust and stellar radial profiles with exponential functions, we fit the far-infrared spectral energy distribution (SED) in each annular region with single-temperature modified black bodies using both variable (MBBV) and fixed (MBBF) emissivity indices beta, as well as with physically motivated dust models. Results show that while most SED parameters decrease with radius, the emissivity index beta also decreases with radius in some galaxies, but in others is increasing, or rising in the inner regions and falling in the outer ones. Despite the fixed grain emissivity (average beta~ 2.1) of the physically-motivated models, they are well able to accommodate flat spectral slopes with beta<= 1. We find that flatter slopes (beta<= 1.5) are associated with cooler temperatures, contrary to what would be expected from the usual Tdust-beta degeneracy. This trend is related to variations in Umin since beta and Umin are very closely linked over the entire range in Umin sampled by the KINGFISH galaxies: low Umin is associated with flat beta<=1. Both these results strongly suggest that the low apparent \beta values (flat slopes) in MBBV fits are caused by temperature mixing along the line-of-sight, rather than by intrinsic variations in grain properties. Abstract truncated for arXiv.
    Full-text · Article · Sep 2014 · Astronomy and Astrophysics
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    ABSTRACT: We study the surface brightness profiles of disc galaxies in the 3.6 μm images from the Spitzer Survey of Stellar Structure in Galaxies (S4G) and Ks-band images from the Near-Infrared S0-Sa galaxy Survey (NIRS0S). We particularly connect properties of single exponential (type I), downbending double exponential (type II), and upbending double exponential (type III) disc profile types, to structural components of galaxies by using detailed morphological classifications, and size measurements of rings and lenses. We also study how the local environment of the galaxies affects the profile types by calculating parameters describing the environmental density and the tidal interaction strength. We find that in majority of type II profiles the break radius is connected with structural components such as rings, lenses, and spirals. The exponential disc sections of all three profile types, when considered separately, follow the disc scaling relations. However, the outer discs of type II, and the inner discs of type III, are similar in scalelength to the single exponential discs. Although the different profile types have similar mean environmental parameters, the scalelengths of the type III profiles show a positive correlation with the tidal interaction strength.
    Full-text · Article · Apr 2014 · Monthly Notices of the Royal Astronomical Society
  • A. Y. K. Bouquin · A. Gil de Paz · S. Boissier · J. C. Muñoz-Mateos
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    ABSTRACT: We have obtained GALEX UV radial surface brightness and color profiles, as well as integrated magnitudes for +1500 galaxies covering ̃70% of the S4G/DAGAL volume-limited sample of nearby galaxies (d < 40Mpc), and combined these with S4G Spitzer/IRAC-3.6 μm photometry. The analysis of the (FUV-NUV) vs. (NUV-[3.6]) color-color and (FUV-NUV) vs. M[3.6] color-magnitude diagrams (CMD) reveal both a narrow so-called “blue sequence”, where Irr through Sb's are located, and a “red cloud”, where E/S0 galaxies reside. This is opposite to the morphology seen in optical CMDs, and in the case of the color-color diagram, it reflects the degeneracy between SFH of disk galaxies and dust extinction (which strongly correlates the FUV-NUV and NUV-[3.6] colors) and could only be seen in its full extent thanks to the statistics and wide range of galaxy masses and types provided by S4G/DAGAL. We find that a large fraction (%) of the galaxies evolving off (or into) this “blue sequence” towards (or from) the “red cloud” are early-type spirals, that we interpret as a sign of strangulation (or re-birth) of the star formation in these galaxies. Such processes lead to distinct FUV-NUV colors, as this color is very sensitive to recent changes in the star formation activity, compared to other colors (optical ones, NUV-optical, or even NUV-[3.6]).
    No preview · Article · Feb 2014
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    ABSTRACT: We present Herschel/PACS 100 and 160 μm integrated photometry for the 323 galaxies in the Herschel Reference Survey (HRS), a K-band, volume-limited sample of galaxies in the local Universe. Once combined with the Herschel/SPIRE observations already available, these data make the HRS the largest representative sample of nearby galaxies with homogeneous coverage across the 100–500 μm wavelength range. In this paper, we take advantage of this unique data set to investigate the properties and shape of the far-infrared/submillimetre spectral energy distribution in nearby galaxies. We show that, in the stellar mass range covered by the HRS (8 ≲ log (M*/M⊙) ≲ 12), the far-infrared/submillimetre colours are inconsistent with a single modified blackbody having the same dust emissivity index β for all galaxies. In particular, either β decreases or multiple temperature components are needed, when moving from metal-rich/gas-poor to metal-poor/gas-rich galaxies. We thus investigate how the dust temperature and mass obtained from a single modified blackbody depend on the assumptions made on β. We show that, while the correlations between dust temperature, galaxy structure and star formation rate are strongly model dependent, the dust mass scaling relations are much more reliable, and variations of β only change the strength of the observed trends.
    Full-text · Article · Feb 2014 · Monthly Notices of the Royal Astronomical Society
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    ABSTRACT: The study of early type galaxies (ellipticals and lenticulars) is undergoing a renaissance with new observations that are confronting our notions of these systems as being old, dead and red. Observations are revealing stellar substructure, gas and dust, star formation and tidal debris in these galaxies, all of which are challenging our understanding of the formation and evolution of these 'simple' systems. Here we propose to assemble a complete survey of all nearby early type galaxies (ETGs) using archival and new observations for all ETGs at d < 40 Mpc (v < 3000.0 km/s), m_B < 15.5, D_25 > 1 arcminute and \|b\| > 30 degrees. We request 188.1 hrs to map 465 ETGs at 3.6 and 4.5 microns - this will provide a statistically robust and complete sample of ETGs with sufficient numbers in each mass, type and environment to study their structure, reconstruct their evolution through stellar populations, assess their recent merger history and ultimately constrain their origins. These data will be the most sensitive probe to date for faint stellar structures such as nuclear cusps, large scale shells and rings, and stellar disks in the largest sample of ETGs ever assembled, providing an extremely sensitive test of current and future models for the formation and evolution of ETGs over cosmic time.
    No preview · Article · Oct 2013
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    ABSTRACT: We study the m = 1 distortions (lopsidedness) in the stellar components of 167 nearby galaxies that span a wide range of morphologies and luminosities. We confirm the previous findings of (1) a high incidence of lopsidedness in the stellar distributions, (2) increasing lopsidedness as a function of radius out to at least 3.5 exponential scale lengths, and (3) greater lopsidedness, over these radii, for galaxies of later type and lower surface brightness. Additionally, the magnitude of the lopsidedness (1) correlates with the character of the spiral arms (stronger arm patterns occur in galaxies with less lopsidedness), (2) is not correlated with the presence or absence of a bar, or the strength of the bar when one is present, (3) is inversely correlated to the stellar mass fraction, f *, within one radial scale length, and (4) correlates directly with f * measured within the radial range over which we measure lopsidedness. We interpret these findings to mean that lopsidedness is a generic feature of galaxies and does not, generally, depend on a rare event, such as a direct accretion of a satellite galaxy onto the disk of the parent galaxy. While lopsidedness may be caused by several phenomena, moderate lopsidedness (A 1i + A 1o )/2 < 0.3) is likely to reflect halo asymmetries to which the disk responds or a gravitationally self-generated mode. We hypothesize that the magnitude of the stellar response depends both on how centrally concentrated the stars are with respect to the dark matter and whether there are enough stars in the region of the lopsidedness that self-gravity is dynamically important.
    Full-text · Article · May 2013 · The Astrophysical Journal
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    ABSTRACT: Local Luminous Compact Blue Galaxies (LCBG) are the closest counterpart of the high z outburst population. These objects are crucial as a local reference for compact star-forming galaxies observed at cosmological distances. We have obtained 2-D spectroscopy in the 3700-7000 Å range with PPAK instrument (at 3.5 m CAHA) for a sample of 22 local LCBGs. In this poster we show the results derived from the 2D analysis of different physical properties in UCM1648+2855, a case study LCBG. It was chosen as a prototype of one of the three kinematic classes observed by Pérez-Gallego, et al. (2011): perturbed rotation. Our study shows that this galaxy has a dichotomy between eastern star-forming region and the western part that shows an old underlying stellar population. UCM1648+2855 has a disc-supported velocity map, perturbed by two large star-forming regions; and an enhanced dust distribution outside the star-forming regions. Therefore the massive star formation in UCM1648+2855 seems to be not driven by merging (or any accompanying galaxy), but by a genuine starburst, with a SFR of ˜ 9 {M}_{⊙}/year.
    No preview · Article · May 2013
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    ABSTRACT: MEGARA (Multi-Espectrógrafo en GTC de Alta Resolución para Astronomía) is an optical Integral-Field Unit (IFU) and Multi-Object Spectrograph (MOS) designed for the GTC 10.4 m telescope in La Palma. MEGARA will be a 3rd generation instrument for GTC. It is led by the University Complutense of Madrid with the collaboration of INAOE, IAA, UPM and comprises more than 50 researchers from a large number of institutions worldwide.
    No preview · Article · May 2013
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    ABSTRACT: Luminous Compact Blue Galaxies (LCBGs) are small, but vigorously star forming galaxies. Their presence at different redshifts denotes their cosmological relevance and implies that local starburst galaxies, when properly selected, are unique laboratories for studying the complex ecosystem of the star formation process over time. We have selected a representative sample of 22 LCBGs from the SDSS and UCM databases which, although small, provides an excellent reference for comparison with current and future surveys of similar starbursts at high-z. We are carrying out a 2D optical spectroscopic study of this LCBG sample, including spatially resolved maps of kinematics, extinction, SFR and metallicity. This will help us to answer questions regarding the nature of these objects. In this poster we show our results on the kinematical study (Pérez-Gallego et al. 2011) which allows us to classify these galaxies into three different classes: rotating disk (RD) 48%, perturbed rotation (PR) 28% and complex kinematics (CK) 24%. We find 5% of objects show evidence of a recent major merger, 10% of a minor merger, and 45% of a companion. This argues in favor of ongoing interactions with close companions as a mechanism for the enhanced star formation activity in these galaxies. We find only 5% of objects with clear evidence of AGN activity, and 27% with kinematics consistent with SN-driven galactic winds. Therefore, a different mechanism may be responsible for quenching the star formation in LCBGs. The detailed analysis of the physical properties for each galaxy in the sample is on progress and we show in this poster the results on UCM2325+2318 as a prototype LCBG. Between the possible mechanisms to explain the starburst activity in this galaxy, our 2D spectroscopic data support the scenario of an on-going interaction with the possibility for clump B to be the dwarf satellite galaxy (Castillo-Morales et al. 2011, Pérez-Gallego et al. 2010).
    No preview · Article · May 2013
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    ABSTRACT: We have analyzed the radial distribution of old stars in a sample of 218 nearby face-on disks, using deep 3.6 μm images from the Spitzer Survey of Stellar Structure in Galaxies. In particular, we have studied the structural properties of those disks with a broken or down-bending profile. We find that, on average, disks with a genuine single-exponential profile have a scale length and a central surface brightness which are intermediate to those of the inner and outer components of a down-bending disk with the same total stellar mass. In the particular case of barred galaxies, the ratio between the break and the bar radii (R br/R bar) depends strongly on the total stellar mass of the galaxy. For galaxies more massive than 1010M ☉, the distribution is bimodal, peaking at R br/R bar ~ 2 and ~3.5. The first peak, which is the most populated one, is linked to the outer Lindblad resonance of the bar, whereas the second one is consistent with a dynamical coupling between the bar and the spiral pattern. For galaxies below 1010M ☉, breaks are found up to ~10 R bar, but we show that they could still be caused by resonances given the rising nature of rotation curves in these low-mass disks. While not ruling out star formation thresholds, our results imply that radial stellar migration induced by non-axisymmetric features can be responsible not only for those breaks at ~2 R bar, but also for many of those found at larger radii.
    Full-text · Article · Apr 2013 · The Astrophysical Journal
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    ABSTRACT: NGC 1097 has an extensive, unique network of jet-like extended structures that stretch out for dozens of kiloparsecs. Their origin has remained a mystery for decades. The evidence for their association with the AGN is weak, and the lack of HI emission in the vicinity makes it unlikely that they are the product of tidal interactions or streams off the main disk of the galaxy. Recent modeling has shown that the structures may be the remnants of a dwarf galaxy, though the type of dwarf remains unclear, and such interactions are complicated by the fact that the main spiral has a large bar. We propose Spitzer observations of these features to determine the streams' true extent, to age-date individual structures by focusing on the old stellar population, estimate their masses, and calculate their metallicities. We will use Spitzer's sensitivity and the degeneracy-breaking IRAC colors to unravel the history of this unusual object. This proposal is part of broader studies by members of this team on galaxy outskirts and interactions, including mergers, streams, shells, asymmetries and lopsidedness, all of which contribute to our understanding of galaxy evolution in the nearby Universe.
    No preview · Article · Dec 2012
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    ABSTRACT: We present a study of the kinematics of the isolated spiral galaxy NGC 864, using Hα Fabry-Perot data obtained with the Galaxy Hα Fabry-Perot System (GHαFaS) instrument at the William Herschel Telescope in La Palma, complemented with images at 3.6 μm, in the R band and in Hα filter, and integral-field spectroscopic data. The resulting data cubes and velocity maps allow the study of the kinematics of the galaxy, including in-depth investigations of the rotation curve, velocity moment maps, velocity residual maps, gradient maps and position-velocity diagrams. We find asymmetries in the velocity field in the bar zone, caused by non-circular motions, probably in response to the potential of the bar. We also find a flat-profile bar, in agreement with the strong bar, with the grand design spiral pattern, and with the gap between the ends of the bar and the start of the spiral arms. We quantify the rate of massive star formation, which is concentrated in the two spiral arms.
    No preview · Article · Dec 2012 · Monthly Notices of the Royal Astronomical Society

Publication Stats

804 Citations
153.33 Total Impact Points

Institutions

  • 2014-2015
    • University of Santiago, Chile
      CiudadSantiago, Santiago Metropolitan, Chile
    • European Southern Observatory
      Arching, Bavaria, Germany
  • 2013-2015
    • Universidad de La Laguna
      • Department of Astrophysics
      San Cristóbal de La Laguna, Canary Islands, Spain
  • 2012-2013
    • National Radio Astronomy Observatory
      Charlottesville, Virginia, United States
  • 2007-2012
    • Complutense University of Madrid
      • • Department of Physics of the Earth, Astronomy and Astrophysics I
      • • Department of Atomic, Molecular and Nuclear Physics
      Madrid, Madrid, Spain