Person:
Catalán Torrecilla, Cristina

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First Name
Cristina
Last Name
Catalán Torrecilla
Affiliation
Universidad Complutense de Madrid
Faculty / Institute
Ciencias Físicas
Department
Física de la Tierra y Astrofísica
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Now showing 1 - 10 of 11
  • Publication
    MEGARA, the R=6000-20000 IFU and MOS of GTC
    (SPIE-Int Soc Optical Engineering, 2018) Gil de Paz, Armando; Gallego Maestro, Jesús; Bouquin, A.; Carbajo, J.; Cardiel López, Nicolás; Castillo Morales, África; Esteban San Román, Segundo; López Orozco, José Antonio; Pascual, S.; Picazo, P.; Sánchez Penim, Ainhoa; Velázquez, M.; Zamorano Calvo, Jaime; Catalán Torrecilla, Cristina; Dullo, Bililign; Pérez González, P.G.; Roca Fábrega, Santi
    MEGARA is the new generation IFU and MOS optical spectrograph built for the 10.4m Gran Telescopio CANARIAS (GTC). The project was developed by a consortium led by UCM (Spain) that also includes INAOE (Mexico), IAA-CSIC (Spain) and UPM (Spain). The instrument arrived to GTC on March 28th 2017 and was successfully integrated and commissioned at the telescope from May to August 2017. During the on-sky commissioning we demonstrated that MEGARA is a powerful and robust instrument that provides on-sky intermediate-to-high spectral resolutions R_(FWHM) ~ 6,000, 12,000 and 20,000 at an unprecedented efficiency for these resolving powers in both its IFU and MOS modes. The IFU covers 12.5 x 11.3 arcsec2 while the MOS mode allows observing up to 92 objects in a region of 3.5 x 3.5 arcmin^(2) . In this paper we describe the instrument main subsystems, including the Folded-Cassegrain unit, the fiber link, the spectrograph, the cryostat, the detector and the control subsystems, and its performance numbers obtained during commissioning where the fulfillment of the instrument requirements is demonstrated.
  • Publication
    CALIFA, the Calar Alto Legacy Integral Field Area survey III. Second public data release
    (EDP Sciencies, 2015-04) Castillo Morales, África; Gil de Paz, Armando; Catalán Torrecilla, Cristina
    This paper describes the Second Public Data Release (DR2) of the Calar Alto Legacy Integral Field Area (CALIFA) survey. The data for 200 objects are made public, including the 100 galaxies of the First Public Data Release (DR1). Data were obtained with the integral-field spectrograph PMAS /PPak mounted on the 3.5 m telescope at the Calar Alto observatory. Two different spectral setups are available for each galaxy, (i) a low-resolution V500 setup covering the wavelength range 3745-7500 Å with a spectral resolution of 6.0 Å (FWHM); and (ii) a medium-resolution V1200 setup covering the wavelength range 3650-4840 Å with a spectral resolution of 2.3 Å (FWHM). The sample covers a redshift range between 0.005 and 0.03, with a wide range of properties in the color-magnitude diagram, stellar mass, ionization conditions, and morphological types. All the cubes in the data release were reduced with the latest pipeline, which includes improved spectrophotometric calibration, spatial registration, and spatial resolution. The spectrophotometric calibration is better than 6% and the median spatial resolution is 2´´ 4. In total, the second data release contains over 1.5 million spectra.
  • Publication
    First scientific observations with MEGARA at GTC
    (Spie-Int Soc Optical Engineering, 2018) Gil de Paz, Armando; Gallego Maestro, Jesús; Bouquin, A.; Carbajo, J.; Cardiel López, Nicolás; Castillo Morales, África; Esteban San Román, Segundo; López Orozco, José Antonioi; Pascual Ramírez, Sergio; Picazo, P.; Sánchez Penim, Ainhoa; Zamorano Calvo, Jaime; Catalán Torrecilla, Cristina; Dullo, Bililign; Pérez González, P.G.
    On June 25th 2017, the new intermediate-resolution optical IFU and MOS of the 10.4-m GTC had its first light. As part of the tests carried out to verify the performance of the instrument in its two modes (IFU & MOS) and 18 spectral setups (identical number of VPHs with resolutions R=6000-20000 from 0.36 to 1 micron) a number of astronomical objects were observed. These observations show that MEGARA@GTC is called to fill a niche of high-throughput, intermediate resolution IFU & MOS observations of extremely-faint narrow-lined objects. Lyman-α absorbers, star-forming dwarfs or even weak absorptions in stellar spectra in our Galaxy or in the Local Group can now be explored to a new level. Thus, the versatility of MEGARA in terms of observing modes and spectral resolution and coverage will allow GTC to go beyond current observational limits in either depth or precision for all these objects. The results to be presented in this talk clearly demonstrate the potential of MEGARA in this regard.
  • Publication
    Star formation in the local Universe from the CALIFA sample. I. Calibrating the SFR using IFS data
    (EDP Sciencies, 2015-12) Catalán Torrecilla, Cristina; Gil de Paz, Armando; Castillo Morales, África; Pérez González, Pablo Guillermo; Marino, Raffaella Anna; otros, ...
    Context. 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 narrowband imaging or long-slit spectroscopy have traditionally posed a limit to their applicability. Integral field spectroscopy (IFS) is clearly the way to overcome this kind of limitation. Aims. We obtain integrated Hα, ultraviolet (UV) and infrared (IR)-based SFR measurements for 272 galaxies from the CALIFA survey at 0.005
  • Publication
    Stellar population gradients in galaxy discs from the CALIFA survey
    (EDP Sciencies, 2014-10) Sánchez Blázquez, P.; Rosales Ortega, F. F.; Méndez Abreu, J.; Pérez, I.; Sánchez, S. F.; Zibetti, S.; Aguerri, J. A. L.; Bland-Hawthorn, J.; Catalán Torrecilla, Cristina; Cid Fernandes, R.; de Amorim, A.; de Lorenzo Cáceres, A.; Falcón Barroso, J.; Galazzi, A.; García Benito, R.; Gil de Paz, Armando; González Delgado, R.; Husemann, B.; Iglesias Paramo, Jorge; Jungwiert, B.; Marino, Raffaella Anna; Márquez, I.; Mast, D.; Mendoza, M. A.; Molla, M.; Papaderos, P.; Ruiz Lara, T.; van de Ven, G.; Walcher, C. J.; Wisotzki, L.
    While studies of gasphase metallicity gradients in disc galaxies are common, very little has been done towards the acquisition of stellar abundance gradients in the same regions. We present here a comparative study of the stellar metallicity and age distributions in a sample of 62 nearly face-on, spiral galaxies with and without bars, using data from the CALIFA survey. We measure the slopes of the gradients and study their relation with other properties of the galaxies. We find that the mean stellar age and metallicity gradients in the disc are shallow and negative. Furthermore, when normalized to the effective radius of the disc, the slope of the stellar population gradients does not correlate with the mass or with the morphological type of the galaxies. In contrast to this, the values of both age and metallicity at similar to 2.5 scale lengths correlate with the central velocity dispersion in a similar manner to the central values of the bulges, although bulges show, on average, older ages and higher metallicities than the discs. One of the goals of the present paper is to test the theoretical prediction that non-linear coupling between the bar and the spiral arms is an efficient mechanism for producing radial migrations across significant distances within discs. The process of radial migration should flatten the stellar metallicity gradient with time and, therefore, we would expect flatter stellar metallicity gradients in barred galaxies. However, we do not find any difference in the metallicity or age gradients between galaxies with and without bars. We discuss possible scenarios that can lead to this lack of difference.
  • Publication
    Outer-disk reddening and gas-phase metallicities: The CALIFA connection
    (EDP Sciencies, 2016-01) Marino, Raffaella Anna; Gil de Paz, Armando; Cardiel López, Nicolás; Castillo Morales, África; Catalán Torrecilla, Cristina; ..., otros.
    We study, for the first time in a statistically significant and well-defined sample, the relation between the outer-disk ionized-gas metallicity gradients and the presence of breaks in the surface brightness profiles of disk galaxies. Sloan Digital Sky Survey (SDSS) g′- and r′-band surface brightness, (g′ – r′) color, and ionized-gasoxygen abundance profiles for 324 galaxies within the Calar Alto Legacy Integral Field Area (CALIFA) survey are used for this purpose. We perform a detailed light-profile classification, finding that 84% of our disks show down- or up-bending profiles (Type II and Type III, respectively), while the remaining 16% are well fitted by one single exponential (Type I). The analysis of the color gradients at both sides of this break shows a U-shaped profile for most Type II galaxies with an average minimum (g′ − r′) color of ~0.5  mag and an ionized-gas metallicity flattening associated with it only in the case of low-mass galaxies. Comparatively, more massive systems show a rather uniform negative metallicity gradient. The correlation between metallicity flattening and stellar mass for these systems results in p-values as low as 0.01. Independent of the mechanism having shaped the outer light profiles of these galaxies, stellar migration or a previous episode of star formation in a shrinking star-forming disk, it is clear that the imprint in their ionized-gas metallicity was different for low- and high-mass Type II galaxies. In the case of Type III disks, a positive correlation between the change in color and abundance gradient is found (the null hypothesis is ruled out with a p-value of 0.02), with the outer disks of Type III galaxies with masses ≤10^10 M_⊙ showing a weak color reddening or even a bluing. This is interpreted as primarily due to a mass downsizing effect on the population of Type III galaxies that recently experienced an enhanced inside-out growth.
  • Publication
    Aperture effects on the oxygen abundance determinations from Califa data
    (American Astronomical Society, 2016-07-20) Gil de Paz, Armando; Catalán Torrecilla, Cristina; Castillo Morales, África; Marino, Raffaella Anna; otros, ...
    This paper aims to provide aperture corrections for emission lines in a sample of spiral galaxies from the Calar Alto Legacy Integral Field Area Survey (CALIFA) database. In particular, we explore the behavior of the log([O III] λ5007/Hβ)/([N II] λ6583/Hα) (O3N2) and log[N II] lambda 6583/Hα (N2) flux ratios since they are closely connected to different empirical calibrations of the oxygen abundances in star-forming galaxies. We compute the median growth curves of Hα, Hα/Hβ, O3N2, and N-2 up to 2.5R(50) and 1.5 disk R-eff. These distances cover most of the optical spatial extent of the CALIFA galaxies. The growth curves simulate the effect of observing galaxies through apertures of varying radii. We split these growth curves by morphological types and stellar masses to check if there is any dependence on these properties. The median growth curve of the Hα flux shows a monotonous increase with radius with no strong dependence on galaxy inclination, morphological type, and stellar mass. The median growth curve of the Hα/HβH ratio monotonically decreases from the center toward larger radii, showing for small apertures a maximum value of ≈10% larger than the integrated one. It does not show any dependence on inclination, morphological type, and stellar mass. The median growth curve of N-2 shows a similar behavior, decreasing from the center toward larger radii. No strong dependence is seen on the inclination, morphological type, and stellar mass. Finally, the median growth curve of O3N2 increases monotonically with radius, and it does not show dependence on the inclination. However, at small radii it shows systematically higher values for galaxies of earlier morphological types and for high stellar mass galaxies. Applying our aperture corrections to a sample of galaxies from the SDSS survey at 0.02 ≤ z ≤ 0.3 shows that the average difference between fiber-based and aperture-corrected oxygen abundances, for different galaxy stellar mass and redshift ranges, reaches typically to ≈11%, depending on the abundance calibration used. This average difference is found to be systematically biased, though still within the typical uncertainties of oxygen abundances derived from empirical calibrations. Caution must be exercised when using observations of galaxies for small radii (e.g., below 0.5 R_eff) given the high dispersion shown around the median growth curves. Thus, the application of these median aperture corrections to derive abundances for individual galaxies is not recommended when their fluxes come from radii much smaller than either R_50 or R_eff.
  • Publication
    Star Formation in the Local Universe from the CALIFA Sample. II. Activation and Quenching Mechanisms in Bulges, Bars, and Disks
    (American Astronomical Society, 2017-10-20) Catalán Torrecilla, Cristina; Gil de Paz, Armando; Castillo Morales, África
    We estimate the current extinction-corrected Ha star formation rate (SFR) of the different morphological components that shape galaxies (bulges, bars, and disks). We use a multicomponent photometric decomposition based on Sloan Digital Sky Survey imaging to Calar Alto Legacy Integral Field Area Integral Field Spectroscopy (IFS) datacubes for a sample of 219 galaxies. This analysis reveals an enhancement of the central SFR and specific SFR (sSFR = SFR/M-star) in barred galaxies. Along the main sequence, we find that more massive galaxies in total have undergone efficient suppression (quenching) of their star formation, in agreement with many studies. We discover that more massive disks have had their star formation quenched as well. We evaluate which mechanisms might be responsible for this quenching process. The presence of type 2 AGNs plays a role at damping the sSFR in bulges and less efficiently in disks. Also, the decrease in the sSFR of the disk component becomes more noticeable for stellar masses around 10(10.5) M-circle dot; for bulges, it is already present at similar to 10(9.5) M-circle dot. The analysis of the line-of-sight stellar velocity dispersions (sigma) for the bulge component and of the corresponding Faber-Jackson relation shows that AGNs tend to have slightly higher sigma values than star-forming galaxies for the same mass. Finally, the impact of environment is evaluated by means of the projected galaxy density, Sigma(5). We find that the SFR of both bulges and disks decreases in intermediate- to high-density environments. This work reflects the potential of combining IFS data with 2D multicomponent decompositions to shed light on the processes that regulate the SFR.
  • Publication
    Stellar populations with MEGARA: The inner regions of NGC 7025
    (EDP Sciencies, 2022-01-18) Chamorro Cazorla, Mario; Gil de Paz, Armando; Castillo Morales, África; Dullo, Bililign T.; Gallego Maestro, Jesús; Carrasco, E.; Iglesias Páramo, J.; Cedazo, R.; García Vargas, M. L.; Pascual Ramírez, Sergio; Cardiel López, Nicolás; Pérez Calpena, A.; Gómez Álvarez, P.; Martínez-Delgado, I.; Catalán Torrecilla, Cristina
    Context. This paper aims to determine the capabilities of the MEGARA spectrograph at the Gran Telescopio Canarias (GTC), which is an optical integral-field unit, for studying stellar populations. We also aim to exploit its combination of high spectral (Rx2004;similar to 6000,12000 and 20 000) and spatial (0.62 '') resolution within its 12 '' .5 x 11 '' .3 field of view. We do this by analysing the commissioning data of the nearby S0a galaxy NGC 7025. Aims. We establish a systematic method through which we can determine the properties of the stellar populations in the observations made with MEGARA, more specifically, within the MEGADES legacy project. For this paper in particular, we determine the properties of the stellar populations of NGC 7025. Methods. We used MEGARA observations of galaxy NGC 7025 that were taken during the commissioning phase of the instrument. We applied different approaches to estimate the properties of the stellar populations with the highest possible certainty. In addition to the specific study of NGC 7025 and in the context of the MEGADES survey, we have carried out a number of tests to determine the expected errors (including potential biases) in these star formation history (SFH) derivations as a function of these parameters, namely spectral setup, signal-to-noise ratio, sigma, and the SFH itself. Results. All the studies we conduct (both full spectral fitting and absorption line indices) of the stellar populations of NGC 7025 indicate that the stars that form its bulge have supersolar metallicity and considerably old ages (similar to 10 Gyr) in general. Using three different combinations of MEGARA spectral setups, we determined that the bulge of NGC 7025 has smild negative mass-weighted age gradient. For the more detailed SFH, our results indicate that in addition to a rather constant star formation at early epochs, a peak in the formation history of the stars in the bulge is also found 3.5-4.5 Gyr ago. This partly explains the mass-weighted age gradients we measured. Conclusions. The scenario presented in NGC 7025 is that of an isolated galaxy under secular evolution that about 3.5-4.5 Gyr ago likely experienced a minor merger (mass ratio 1/10) that induced an increase in star formation and also perturbed the morphology of its outer disc. In addition to these specific results for NGC 7025, we report different lessons learned for the ongoing exploitation of the MEGADES survey with the GTC, such as the need to obtain combined observations in the LR-B + LR-V setups and a signal-to-noise ratio of at least 20 per angstrom.
  • Publication
    CALIFA, the Calar Alto Legacy Integral Field Area survey
    (EDP Sciencies, 2013-01) Castillo Morales, África; Catalán Torrecilla, Cristina; Marino, Raffaella Anna; Gil de Paz, Armando; Mollá, M.
    We present the first public data release (DR1) of the Calar Alto Legacy Integral Field Area (CALIFA) survey. It consists of science-grade optical datacubes for the first 100 of eventually 600 nearby (0.005 < z < 0.03) galaxies, obtained with the integral-field spectrograph PMAS/PPak mounted on the 3.5 m telescope at the Calar Alto observatory. The galaxies in DR1 already cover a wide range of properties in color-magnitude space, morphological type, stellar mass, and gas ionization conditions. This offers the potential to tackle a variety of open questions in galaxy evolution using spatially resolved spectroscopy. Two different spectral setups are available for each galaxy, (i) a low-resolution V500 setup covering the nominal wavelength range 3745-7500 angstrom with a spectral resolution of 6.0 angstrom (FWHM), and (ii) a medium-resolution V1200 setup covering the nominal wavelength range 3650-4840 angstrom with a spectral resolution of 2.3 angstrom (FWHM). We present the characteristics and data structure of the CALIFA datasets that should be taken into account for scientific exploitation of the data, in particular the effects of vignetting, bad pixels and spatially correlated noise. The data quality test for all 100 galaxies showed that we reach a median limiting continuum sensitivity of 1.0 x 10(-18) erg s(-1) cm(-2) angstrom(-1) arcsec(-2) at 5635 angstrom and 2.2 x 10(-18) erg s(-1) cm(-2) angstrom(-1) arcsec(-2) at 4500 angstrom for the V500 and V1200 setup respectively, which corresponds to limiting r and g band surface brightnesses of 23.6 mag arcsec(-2) and 23.4 mag arcsec(-2), or an unresolved emission-line flux detection limit of roughly 1 x 10(-17) erg s(-1) cm(-2) arcsec(-2) and 0.6 x 10(-17) erg s(-1) cm(-2) arcsec(-2), respectively. The median spatial resolution is 3 ''.7, and the absolute spectrophotometric calibration is better than 15% (1 sigma). We also describe the available interfaces and tools that allow easy access to this first public CALIFA data at http://califa.caha.es/DR1.