Person: Zamorano Calvo, Jaime
Loading...
First Name
Jaime
Last Name
Zamorano Calvo
Affiliation
Universidad Complutense de Madrid
Faculty / Institute
Ciencias FÃsicas
Department
FÃsica de la Tierra y AstrofÃsica
Area
AstronomÃa y AstrofÃsica
Identifiers
52 results
Search Results
Now showing 1 - 10 of 52
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, MarÃa 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 3C a multi-wavelength database for the future GTC cosmological surveys(First light science with the GTC, 2007) Barro, G.; Gallego Maestro, Jesús; Villar, V.; Zamorano Calvo, JaimeThe 3C Database aims to provide complete multi-wavelength information over different cosmological fields, such as GOODS, Groth or Sa68 allowing detailed studies on wide samples of galaxies.Item The stellar mass assembly of galaxies from z=0 to z=4: Analysis of a sample selected in the rest-frame near-infrared with Spitzer(Astrophysical journal, 2008) Pérez González, Pablo Guillermo; Rieke, George H.;, George H.; Villar, Victor; Barro, Guillermo; Blaylock, Myra; Egami, Eiichi; Gallego Maestro, Jesús; Gil de Paz, Armando; Pascual, Sergio; Zamorano Calvo, Jaime; Donley, Jennifer L.Using a sample of ~28,000 sources selected at 3.6-4.5 μm with Spitzer observations of the Hubble Deep Field North, the Chandra Deep Field South, and the Lockman Hole (surveyed area ~664 arcmin^2), we study the evolution of the stellar mass content of the universe at 0 < z < 4. We calculate stellar masses and photometric redshifts, based on ~2000 templates built with stellar population and dust emission models fitting the ultraviolet to mid-infrared spectral energy distributions of galaxies with spectroscopic redshifts. We estimate stellar mass functions for different redshift intervals. We find that 50% of the local stellar mass density was assembled at 0 < z < 1 (average star formation rate [SFR] 0.048 M-☉ yr^−1 Mpc^−3), and at least another 40% at 1 < z < 4 (average SFR 0.074 M_☉ yr^−1 Mpc^−3). Our results confirm and quantify the "downsizing" scenario of galaxy formation. The most massive galaxies (M > 10^12.0 M_☉) assembled the bulk of their stellar content rapidly (in 1-2 Gyr) beyond z ~ 3 in very intense star formation events (producing high specific SFRs). Galaxies with 10^11.5 < M < 10^12.0 M_☉ assembled half of their stellar mass before z ~ 1.5, and more than 90% of their mass was already in place at z ~ 0.6. Galaxies with M < 1011.5 M☉ evolved more slowly (presenting smaller specific SFRs), assembling half of their stellar mass below z ~ 1. About 40% of the local stellar mass density of 10^9.0 < M < 10^11.0 M_☉ galaxies was assembled below z ~ 0.4, most probably through accretion of small satellites producing little star formation. The cosmic stellar mass density at z > 2.5 is dominated by optically faint (Rgsim 25) red galaxies (distant red galaxies or BzK sources), which account for ~30% of the global population of galaxies, but contribute at least 60% of the cosmic stellar mass density. Bluer galaxies (e.g., Lyman break galaxies) are more numerous but less massive, contributing less than 50% of the global stellar mass density at high redshift.Item Star formation in the nucleus of the galaxy NGC-5253(Astronomy and astrophysics, 1987) González-Riestra, R.; Rego Fernández, Manuel Eduardo; Zamorano Calvo, JaimeSummary. Optical and ultraviolet spectroscopic observations of the nucleus of the galaxy NGC5253 are analyzed. This galaxy presents the typical features of an elliptical system at large distances from its center. However, its nucleus is dominated by an emission complex composed by severa) giant H rr regions. The analysis of the optical spectra shows that the metallic abundances in the nucleus of the galaxy are below the solar values. The presence of O stars can be deduced from the numerous absorption Iines present in the UV spectrum. The UV emission lines indicate a high effective temperature for the ionizing star cluster. The comparison of the observations with evolutive models of W(Hp) and the slope of the UV continuum shows that the age of the brightest knot of the nucleus of NGC 5253 is less than three millions years. The exact age depends on the choice of the extinction law, not well known in this type of objects. An LMC like law (consistent with the low metallicity of the object) leads to an age of 2.3 106 yr, and to an IMF similar or slightly flatter than that found by Salpeter for the solar neighbourhood, with an upper mass limit in the range 60 M 0 < M0P < 120 M 0 .Item CO^(12) mapping of the low-metallicity blue compact dwarf galaxy Markarian 86(Astrophysical journal, 2002) Gil de Paz, Armando; Silich, S. A.; Madore, B. F.; Sánchez Contreras, C.; Zamorano Calvo, Jaime; Gallego Maestro, JesúsWe have mapped the CO^12 J = 1-0 and J = 2-1 line emission in Markarian 86, one of the most metal-deficient blue compact dwarf galaxies so far detected in CO^12. The CO^12 emission is distributed in a horseshoe-like structure that follows the locus of the most recent star formation regions. The minimum in molecular line emission corresponds to the position of an older, massive nuclear starburst. The H_2 mass of the galaxy [in the range of (0.4-5) x 10^7 M_⨀] and its morphology have been compared with the predictions of hydrodynamic simulations of the evolution of the interstellar medium surrounding a nuclear starburst. These simulations suggest that the physical conditions in the gas swept out by the starburst could have led to the formation of the ring of molecular gas reported here. This result provides an attractive scenario for explaining the propagation (in a galactic scale) of the star formation in dwarf galaxies.Item Spectroscopic properties and luminosity distribution of the Universidad Complutense de Madrid survey galaxies(Astrophysical journal, 1997) Gallego Maestro, Jesús; Zamorano Calvo, Jaime; Rego Fernández, Manuel; Vitores, A. G.A spectroscopic analysis of the entire sample of Ha emission-line galaxies (ELGs) contained in lists 1 and 2 of the Universidad Complutense de Madrid (UCM) objective-prism survey is presented. A significant fraction (59%) of star-forming galaxies with low-ionization or high-extinction properties has been found. This kind of ELG is only incompletely detected in the blue or in other ELG surveys. We have found evidence for evolution among some of the different ELG classes. A comparison between the populations detected by the Case, Kiso, University of Michigan, and UCM surveys is presented. We conclude that a deep H_α survey is better able to sample all the ages, evolutionary stages, and luminosities of currently star-forming galaxies than other surveys using blue emission lines or colors. Finally, the luminosity and spatial distributions of the UCM galaxies are determined. The contribution of the newly found, currently star-forming ELGs provides new clues to galaxy evolution and has to be taken into account when trying to consider the density of ELGs and total star formation rate in the universe.Item Specific star formation rate profiles in nearby spiral galaxies: Quantifying the inside-out formation of disks(Astrophysical journal, 2007) Muñoz Mateos, J. C.; Gil de Paz, Armando; Boissier, S.; Zamorano Calvo, Jaime; Jarrett, T.; Gallego Maestro, Jesús; Madore, B. F.We present specific star formation rate (sSFR) radial profiles for a sample of 161 relatively face-on spiral galaxies from the GALEX Atlas of NearbyGalaxies. The sSFR profiles are derived from GALEX and 2MASS (FUV-K) color profiles after a proper SFR calibration of the UV luminosity and K-band mass-to-light ratio are adopted. The (FUV-K) profiles were first corrected for foreground Galactic extinction and later for internal extinction using the ratio of the total-infrared (TIR) to FUV emission. For those objects where TIR-to-FUV ratio radial profiles were not available, the (FUV-NUV) color profiles were used as a measure of the UV slope. The sSFR radial gradients derived from these profiles allow us to quantify the inside-out scenario for the growth of spiral disks for the first time in the local universe. We find a large dispersion in the slope of the sSFR profiles with a slightly positive mean value, which implies a moderate inside-out disk formation. There is also a strong dependency of the value of this slope on the luminosity and size of the disks, with large systems showing a uniform, slightly positive slope in almost all cases and low-luminosity small disks showing a large dispersion with both positive and negative large values. While a majority of the galaxies can be interpreted as forming stars gradually either from inside out or from outside in, a few disks require episodes of enhanced recent growth with scale lengths of the SFR (or gas infall) being significantly larger at present than in the past. We do not find any clear dependence of the sSFR gradient on the environment (local galaxy density or presence of close neighbors).Item Mapping the star formation history of Mrk 86 II. Stellar populations and global interpretation(Astronomy and astrophysics, 2000) Gil de Paz, Armando; Zamorano Calvo, Jaime; Gallego Maestro, JesúsIn this paper, continuation of Gil de Pat et al. (Paper I), we derive the main properties of the stellar populations in the Blue Compact Dwarf galaxy Mrk 86. Ages, stellar masses, metallicites and burst strengths have been obtained using the combination of Monte Carlo simulations, a maximum likelihood estimator and Cluster and Principal Component Analysis. The three stellar populations detected show well defined properties. We have studied the underlying stellar population, which shows an age between 5-13 Gyr and no significant color gradients. The intermediate aged (30 Myr old) central starburst show a very low dust extinction with high burst strength and high stellar mass content (∼9x10^6 M_⨀). Finally, the properties of 46 low-metallicity (∼1/10Z_⨀) star-forming regions were also studied. The properties derived suggest that the most recent star-forming activity in Mrk 86 was triggered by the evolution of a superbubble originated at the central starburst by the energy deposition of stellar winds and supernova explosions. This superbubble produced the blowout of a fraction of the interstellar medium at distances of about 1 kpc with high gas surface densities, leading to the activation of the star formation. Finally, different mechanisms for the star formation triggering in this massive central starburst are studied, including the merging with a low mass companion and the interaction with UGC 4278. We have assumed a distance to Mrk 86 of 6.9 Mpc.Item Exploring the evolutionary paths of the most massive galaxies since z ~ 2(Astrophysical journal, 2008) Pérez González, Pablo Guillermo; Trujillo, Ignacio; Barro, Guillermo; Gallego Maestro, Jesús; Zamorano Calvo, Jaime; Conselice, Christopher J.We use Spitzer MIPS data from the FIDEL Legacy Project in the extended Groth strip to analyze the stellar mass assembly of massive (M > 1011 M_☉) galaxies at z < 2 as a function of structural parameters. We find 24 μm emission for more than 85% of the massive galaxies morphologically classified as disks, and for more than 57% of the massive systems morphologically classified as spheroids at any redshift, with about 8% of sources harboring a bright X-ray- and/or infrared-emitting AGN. More noticeably, ~60% of all compact massive galaxies at z = 1–2 are detected at 24 μm, even when rest-frame optical colors reveal that they are dead and evolving passively. For spheroid-like galaxies at a given stellar mass, the sizes of MIPS nondetections are smaller by a factor of ~1.2 in comparison with IR-bright sources. We find that disklike massive galaxies present specific SFRs ranging from 0.04 to 0.2 Gyr^−1 at z < 1 (SFRs ranging from 1 to 10 M_☉ yr^−1), typically a factor of 3-6 higher than massive spheroid-like objects in the same redshift range. At z > 1, and more pronouncedly at z > 1.3, the median specific SFRs of the disks and spheroids detected by MIPS are very similar, ranging from 0.1 to 1 Gyr^−1 (SFR = 10–200 M_☉ yr^−1). We estimate that massive spheroid-like galaxies may have doubled (at the most) their stellar mass from star-forming events at z < 2: less than 20% mass increase at 1.7 < z < 2.0, up to 40% more at 1.1 < z < 1.7, and less than 20% additional increase at z < 1. Disklike galaxies may have tripled (at the most) their stellar mass at z < 2 from star formation alone: up to ~40% mass increase at 1.7 < z < 2.0, and less than 180% additional increase below z = 1.7 occurred at a steady rate.Item Mapping the star formation history of Mrk 86 - I. Data and models(Astronomy & astrophysics supplement series, 2000) Gil de Paz, Armando; Zamorano Calvo, Jaime; Gallego Maestro, Jesús; DomÃnguez, F. de B.We have obtained optical (BVR, [O III]Æ› 5007 Ã… and H_α), near infrared (JHK) imaging and long-slit optical spectroscopy for the Blue Compact Dwarf galaxy Mrk 86 (NGC 2537). In this paper, the first of two, we present optical-near-infrared colors and emission-line fluxes for the currently star-forming regions, intermediate aged starburst and underlying stellar population. We also describe the evolutionary synthesis models used in Paper II. The R and H_α luminosity distributions of the galaxy star-forming regions show maxima at M-R = -9.5^m and L_H_α = 10^37.3 ergs^-l. The underlying stellar population shows an exponential surface brigthness profile with central value, μ_E,0 = 21.5 mag arcsec^-2, and scale, α=0.88 kpc, both measured in the R-band image. In the galaxy outer regions, dominated by this component, no significant color gradients are observed. Finally, a complete set of evolutionary synthesis models have been developed, covering a wide range in metallicity, 1/50 Z_⨀< Z < 2 Z_⨀, and burst strength, 1-10^-4. These models include nebular continuum and recombination and forbidden-line emission.