Person: Zamorano Calvo, Jaime
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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
17 results
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Now showing 1 - 10 of 17
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 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 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 The galaxy major merger fraction to z ~ 1(Astronomy and astrophysics, 2009) López Sanjuan, C.; Balcells, M.; Pérez González, Pablo Guillermo; Barro, Guillermo; GarcÃa Dabó, C. E.; Gallego Maestro, Jesús; Zamorano Calvo, JaimeAims. The importance of disc-disc major mergers in galaxy evolution remains uncertain. We study the major merger fraction in a SPITZER/IRAC-selected catalogue in the GOODS-S field up to z ~ 1 for luminosity- and mass-limited samples. Methods. We select disc-disc merger remnants on the basis of morphological asymmetries/distortions, and address three main sources of systematic errors: (i) we explicitly apply morphological K-corrections; (ii) we measure asymmetries in galaxies artificially redshifted to z_d = 1.0 to deal with loss of morphological information with redshift; and (iii) we take into account the observational errors in z and A, which tend to overestimate the merger fraction, though use of maximum likelihood techniques. Results. We obtain morphological merger fractions (f_m^mph) below 0.06 up to z ~ 1. Parameterizing the merger fraction evolution with redshift as f_m^mph (z) = f_m^mph (0)(1 + z)^m, we find that m = 1.8 ± 0.5 for M(B)≤ -20 galaxies, while m = 5.4 ± 0.4 for M_* ≥ 10^10 M_⨀ galaxies. When we translate our merger fractions to merger rates (R_m^mph), their evolution, parameterized as R_m^mph (z) = R_m^mph (0)(1+ z)^n, is quite similar in both cases: n = 3.3 ± 0.8 for M(B) ≤ -20 galaxies, and n = 3.5 ± 0.4 for M_* ≥10^10 M_⨀ galaxies. Conclusions. Our results imply that only similar to 8% of today's M(star) ≥ 10^10 M_⨀ galaxies have undergone a disc-disc major merger since z ~ 1. In addition, ~ 21% of M_* ≥ 10(10) M_⨀ galaxies at z ~ 1 have undergone one of these mergers since z similar to 1.5. This suggests that disc-disc major mergers are not the dominant process in the evolution of M_* ≥ 10(10) M_⨀ galaxies since z 1, with only 0.2 disc-disc major mergers per galaxy, but may be an important process at z > 1, with ~ 1 merger per galaxy at 1 < z < 3.Item Properties of Hα-selected star-forming galaxies from z ∼ 0.8 to now(II International GTC Workshop: Science with GTC 1st-Light Instruments and the LMT, Gallego Maestro, Jesús y Zamorano Calvo, Jaime y Pascual RamÃrez, Sergio y Villar, V. (2005) Emission-line galaxy surveys with GTC: The Hα Universe. In II International GTC Workshop: Science with GTC 1st-Light Instruments and the LMT, 2005) Pascual RamÃrez, Sergio; Villar, V.; Gallego Maestro, Jesús; Zamorano Calvo, Jaime; Pelló, R.; DÃaz-Guerra Viejo, Carlos; Aragón Salamanca, A.We present a long-term project to study the characteristics and evolution of current star-forming galaxies at different redshifts. Our results support the idea that the higher Star Formation Density measured at redshift z=0.24 is due to an increase of the density of bursting galaxies and not to an intrinsic change on overall galaxy properties.Item The Hα nature of the universe at Z∼0.83(First light science with the GTC, 2007) Villar, V.; Gallego Maestro, Jesús; Pascual RamÃrez, Sergio; Zamorano Calvo, Jaime; Noeske, K.; Koo, D.C.We presen there the results of a survey searching for current-star forming galaxies at at z ∼0.83. Objects are selected by their emission in the Hα line through the narrow band filter technique.Item The Hα-based star formation rate density of the universe at z=0.84(Astrophysical journal, 2008) Villar, Victor; Gallego Maestro, Jesús; Pérez González, Pablo Guillermo; Pascual, Sergio; Noeske, Kai; Koo, David C.; Barro, Guillermo; Zamorano Calvo, JaimeWe present the results of an Hα near-infrared narrowband survey searching for star-forming galaxies at redshift z = 0.84. This work is an extension of our previous narrowband studies in the optical at lower redshifts. After removal of stars and redshift interlopers (using spectroscopic and photometric redshifts), we build a complete sample of 165 Hα emitters in the extended Groth strip and GOODS-N fields with L(Hα) > 10^41 ergs s^−1. We compute the Hα luminosity function at z = 0.84 after corrections for [N_Ï€] flux contamination, extinction, systematic errors, and incompleteness. Our sources present an average dust extinction of A(H α) = 1.5 mag. Adopting Hα as a surrogate for the instantaneous SFR, we measure an extinction-corrected SFR density of 0.17^+0.03_−0.03 M_☉ yr^−1 Mpc^−3. Combining this result to our prior measurements at z = 0.02, 0.24, and 0.40, we derive an Hα-based evolution of the SFR density proportional to (1 + z)^β with β = 3.8 ± 0.5. This evolution is consistent with that derived by other authors using different SFR tracers.Item Extended UV (XUV) Emission in Nearby Galaxy Disks(Formation and evolution of galaxy disks, 2008) Gil de Paz, Armando; DÃaz Lopez, Cristina; Zamorano Calvo, Jaime; Gallego Maestro, Jesús; Muñoz Mateos, Juan Carlos; Pérez González, Pablo Guillermo; otros, ...; Funes, José G.; Corsini, Enrico MariaWe summarize the main properties of the extended UV (XUV) emission found in roughly 30% of the nearby spiral galaxies observed by the GALEX satellite. Two different classes of XUV disks are identified, the Type 1 XUV disks where significant, structured UV-bright features are found beyond the classical azimuthally-averaged star-formation threshold, and the Type 2 XUV disks, which are characterized by very extended (seven times the area where most of the stellar mass is found), blue ((FUV-K)<5 mag) outer disks. These latter disks are extreme examples of galaxies growing inside-out. The few XUV disks studied in detail to date are rich in H I but relatively poor in molecular gas, have stellar populations with luminosity-weighted ages of ∼1 Gyr, and ionized-gas metal abundances of ∼Z_⊙/10. As part of the CAHA-XUV project we are in the process of obtaining deep multi-wavelength imaging and spectroscopy of 65 XUV-disk galaxies so to determine whether or not these properties are common among XUV disks.