Person: Zamorano Calvo, Jaime
Loading...
First Name
Jaime
Last Name
Zamorano Calvo
Affiliation
Universidad Complutense de Madrid
Faculty / Institute
Ciencias Físicas
Department
Física de la Tierra y Astrofísica
Area
Astronomía y Astrofísica
Identifiers
3 results
Search Results
Now showing 1 - 3 of 3
Item On the nature of the extragalactic number counts in the K-band(Astronomy & Astrophysics, 2009) Barro, G.; Gallego Maestro, Jesús; Pérez González, Pablo Guillermo; Eliche Moral, María del Carmen; Balcells, M.; Villar, V.; Cardiel López, Nicolás; Cristobal Hornillos, D.; Gil de Paz, Armando; Guzmán, R.; Pello, R.; Prieto, M.; Zamorano Calvo, JaimeContext. The galaxy number counts has been traditionally used to test models of galaxy evolution. However, the origin of significant differences in the shape of number counts at different wavelengths is still unclear. By relating the most remarkable features in the number counts with the underlying galaxy population it is possible to introduce further constraints on galaxy evolution. Aims. We aim to investigate the causes of the different shape of the K-band number counts when compared to other bands, analyzing in detail the presence of a change in the slope around K similar to 17.5. Methods. We present a near-infrared imaging survey, conducted at the 3.5 m telescope of the Calar Alto Spanish-German Astronomical Center (CAHA), covering two separated fields centered on the HFDN and the Groth field, with a total combined area of similar to 0.27 deg(2) to a depth of K similar to 19 (3 sigma, Vega). By combining our data with public deep K-band images in the CDFS (GOODS/ISAAC) and high quality imaging in multiple bands, we extract K-selected catalogs characterized with highly reliable photometric redshift estimates. We derive redshift binned number counts, comparing the results in our three fields to sample the effects of cosmic variance. We derive luminosity functions from the observed K-band in the redshift range [0.25-1.25], that are combined with data from the references in multiple bands and redshifts, to build up the K-band number count distribution. Results. The overall shape of the number counts can be grouped into three regimes: the classic Euclidean slope regime (d log N/dm similar to 0.6) at bright magnitudes; a transition regime at intermediate magnitudes, dominated by M* galaxies at the redshift that maximizes the product phi*dVc/d Omega; and an alpha dominated regime at faint magnitudes, where the slope asymptotically approaches -0.4(alpha + 1) controlled by post-M* galaxies. The slope of the K-band number counts presents an averaged decrement of similar to 50% in the range 15.5 < K < 18.5 (d log N/dm similar to 0.6-0.30). The rate of change in the slope is highly sensitive to cosmic variance effects. The decreasing trend is the consequence of a prominent decrease of the characteristic density phi(K,obs)* (similar to 60% from z = 0.5 to z = 1.5) and an almost flat evolution of M(K,obs)* (1 sigma compatible with M(K,obs)* = -22.89 +/- 0.25 in the same redshift range).Item Secular Evolution of Bulges Induced by Satellite Accretion(Formation and evolution of galaxy disks, 2008) Eliche Moral, María del Carmen; González García, A. C.; Balcells, M.; Aguerri, J. A. L.; Gallego Maestro, Jesús; Zamorano Calvo, JaimeSatellite accretion events have been invoked for mimicking the internal secular evolutionary processes of bulge growth (Kormendy & Kennicutt 2004). In order to investigate this question, we perform N-body models of the accretion of satellites onto disk galaxies. A scaling between the primary and the satellite based on the Tully-Fisher relation ensures that the density ratios, critical to the outcome of the accretion; are realistic. Both the bulge-to-disk ratio and the Sersic index of the remnant bulge increase as a result of the accretion. The dominant mechanism for bulge growth is the inward flow of material from the primary disk to the bulge region during the satellite decay. The models confirm that the growth of the bulge out of disk material, a central ingredient of secular evolution models, may be triggered externally through satellite accretion. This work is described in more detail in Eliche-Moral et al. (2006).Item Formation of SO galaxies through mergers: antitruncated stellar discs resulting from major mergers(Astronomy and astrophysics, 2004) Borlaff, Alejandro; Eliche Moral, María del Carmen; Rodríguez Pérez, Cristina; Querejeta, Miguel; Tapia, Tinidad; Pérez González, Pablo Guillermo; Zamorano Calvo, Jaime; Gallego Maestro, Jesús; Beckman, JohnContext. Lenticular galaxies (S0’s) are more likely to host antitruncated (Type-III) stellar discs than galaxies of later Hubble types. Major mergers are popularly considered too violent mechanisms to form these breaks. Aims. We have investigated whether major mergers can result into S0-like remnants with realistic antitruncated stellar discs or not. Methods. We have analysed 67 relaxed S0 and E/S0 remnants resulting from dissipative N-body simulations of major mergers from the GalMer database. We have simulated realistic R-band surface brightness profiles of the remnants to identify those with antitruncated stellar discs. Their inner and outer discs and the breaks have been quantitatively characterized to compare with real data. Results. Nearly 70% of our S0-like remnants are antitruncated, meaning that major mergers that result in S0’s have a high probability of producing Type-III stellar discs. Our remnants lie on top of the extrapolations of the observational trends (towards brighter magnitudes and higher break radii) in several photometric diagrams, due to the higher luminosities and sizes of the simulations compared to observational samples. In scale-free photometric diagrams, simulations and observations overlap and the remnants reproduce the observational trends, so the physical mechanism after antitruncations is highly scalable. We have found novel photometric scaling relations between the characteristic parameters of the antitruncations in real S0’s, which are also reproduced by our simulations. We show that the trends in all the photometric planes can be derived from three basic scaling relations that real and simulated Type-III S0’s fulfill: h_i ∝ R_brkIII, h_o ∝ R_brkIII, and μ_brkIII ∝ R_brkIII, where h_i and h_o are the scalelenghts of the inner and outer discs, and μ_brkIII and R_brkIII are the surface brightness and radius of the breaks. Bars and antitruncations in real S0’s are structurally unrelated phenomena according to the studied photometric planes. Conclusions. Mayor mergers provide a feasible mechanism to form realistic antitruncated S0 galaxies.