Person: Pérez González, Pablo Guillermo
Loading...
First Name
Pablo Guillermo
Last Name
Pérez González
Affiliation
Universidad Complutense de Madrid
Faculty / Institute
Ciencias Físicas
Department
Area
Astronomía y Astrofísica
Identifiers
111 results
Search Results
Now showing 1 - 10 of 111
Item Exploring the star forming regions in vigorous star forming galaxies at Z=0.84(Fourth science meeting with the GTC, 2013) Villar, V.; Guzmán, R.; Gallego Maestro, Jesús; Pérez González, Pablo Guillermo; Zamorano Calvo, JaimeWe analyze the properties of star forming regions in a sample of star forming galaxies at z = 0.84. Star forming regions are extracted from B band ACS-HST images. Previously we have substracted a model of the galaxy, fitting a bulged+disk model to the whole galaxy. Special care has been taken masking the star forming regions in the model fitting procedure, yielding more reliable results. We present here the properties of these star forming regions.Item Integral field spectroscopy and multi-wavelength imaging of nearby spiral galaxies: NGC 5668 as a pilot case for MEGARA(Fourth Science meeting with the GTC, 2013) Marino, Raffaella Anna; Castillo Morales, María África; Muñoz Mateos, J. C.; Sánchez, S. F.; Gil De Paz, Armando; Pérez González, Pablo Guillermo; Zamorano Calvo, Jaime; Gallego Maestro, Jesús; Alonso Herrera, A.; Kannappan, S.; Boissier, S.; Eliche Moral, María del Carmen; García Vargas, M. L.; Carrasco, E.; Vílchez, J. M.; Sánchez Moreno, F. M.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.Item Integral field spectroscopy and multi-wavelength imaging of the nearby spiral galaxy ngc 5668*: an unusual flattening in metallicity gradient(Astrophysical journal, 2012) Marino, Raffaella Anna; Castillo Morales, María África; Gil De Paz, Armando; Muñoz Mateos, J. C.; Sánchez, S. F.; Pérez González, Pablo Guillermo; Gallego Maestro, Jesús; Zamorano Calvo, Jaime; Alonso Herrero, A.; Boissier, S.We present an analysis of the full bidimensional optical spectral cube of the nearby spiral galaxy NGC 5668, observed with the Pmas fiber PAcK Integral Field Unit (IFU) at the Calar Alto observatory 3.5 m telescope. We make use of broadband imaging to provide further constraints on the evolutionary history of the galaxy. This data set will allow us to improve our understanding of the mechanisms that drive the evolution of disks. We investigated the properties of 62 H II regions and concentric rings in NGC 5668 and derived maps in ionized-gas attenuation and chemical (oxygen) abundances. We find that while inward of r similar to 36 '' similar to 4.4 kpc similar to 0.36 (D-25/2) the derived O/H ratio follows the radial gradient typical of spiral galaxies, the abundance gradient beyond r similar to 36 '' flattens out. The analysis of the multi-wavelength surface brightness profiles of NGC 5668 is performed by fitting these profiles with those predicted by chemo-spectrophotometric evolutionary models of galaxy disks. From this, we infer a spin and circular velocity of lambda = 0.053 and nu(c) = 167 km s(-1), respectively. The metallicity gradient and rotation curve predicted by this best-fitting galaxy model nicely match the values derived from the IFU observations, especially within r similar to 36 ''. The same is true for the colors despite some small offsets and a reddening in the bluest colors beyond that radius. On the other hand, deviations of some of these properties in the outer disk indicate that a secondary mechanism, possibly gas transfer induced by the presence of a young bar, must have played a role in shaping the recent chemical and star formation histories of NGC 5668.Item Quantifying the suppression of the (un)-obscured star formation in galaxy cluster cores at 0.2 less than or similar to z less than or similar to 0.9(Monthly notices of the Royal Astronomical Society, 2019) Pérez González, Pablo GuillermoWe quantify the star formation (SF) in the inner cores (R/R_(200) ≤0.3) of 24 massive galaxy clusters at 0.2 z 0.9 observed by the Herschel Lensing Survey and the Cluster Lensing and Supernova survey with Hubble. These programmes, covering the rest-frame ultraviolet to far-infrared regimes, allow us to accurately characterize stellar mass-limited (M_(∗) > 10^(10) M_(ʘ)) samples of star-forming cluster members (not)-detected in the mid- and/or far-infrared. We release the catalogues with the photometry, photometric redshifts, and physical properties of these samples. We also quantify the SF displayed by comparable field samples from the Cosmic Assembly Near-infrared Deep Extragalactic Legacy Survey. We find that in intermediatez cluster cores, the SF activity is suppressed with respect the field in terms of both the fraction (F) of star-forming galaxies (SFGs) and the rate at which they form stars (SFR and sSFR = SFR/M_(∗)). On average, the F of SFGs is a factor ∼2 smaller in cluster cores than in the field. Furthermore, SFGs present average SFR and sSFR typically ∼0.3 dex smaller in the clusters than in the field along the whole redshift range probed. Our results favour long time-scale quenching physical processes as the main driver of SF suppression in the inner cores of clusters since z ∼0.9, with shorter time-scale processes being very likely responsible for a fraction of the missing SFG population.Item A deeper look at the dust attenuation law of star-forming galaxies at high redshift(Monthly noticies of the royal astronomical society, 2019) Tress, M.; Ferreras, I.; Pérez González, Pablo Guillermo; Bressan, A.; Barro, G.; Domínguez Sánchez, H.; Eliche Moral, María del CarmenA diverse range of dust attenuation laws is found in star-forming galaxies. In particular, Tress et al. (2018) studied the SHARDS survey to constrain the NUV bump strength (B) and the total-to-selective ratio (R_(V)) of 1,753 star-forming galaxies in the GOODS-N field at 1.5Item GUAIX: The UCM Group of Extragalactic Astrophysics and Astronomical Instrumentation(Highlights of Spanish Astrophysics, 2010) Cardiel López, Nicolás; Gallego Maestro, Jesús; Pascual Ramírez, Sergio; Eliche Moral, María del Carmen; Castillo Morales, María África; Guzmán, R.; Gil De Paz, Armando; Pérez González, Pablo Guillermo; Gorgas García, Francisco Javier; Zamorano Calvo, JaimeWe present a short summary of the activities developed by GUAIX, the Universidad Complutense de Madrid (UCM) Group of Extragalactic Astrophysics and Astronomical Instrumentation. At present we are focused in the development of data reduction pipelines for several future instruments for the Spanish 10m GTC (Gran Telescopio Canarias). The careful treatment of the random error propagation throughout the data reduction is one of the main improvements of those pipelines. The first hardware development leaded by the GUAIX group will be FISIR, a fully-cryogenic (optimized for the K band) tunable filter in the near-infrared, to be installed within CIRCE, a near-IR camera for GTC.Item KMOS LENsing Survey (KLENS): Morpho-kinematic analysis of star-forming galaxies at z ~ 2(Astronomy and Astrophysics, 2018) Girard, M.; Dessauges-Zavadsky, M.; Schaerer, D.; Cirasuolo, M.; Turner, O. J.; Cava, A.; Rodríguez Muñoz, L.; Richard, J.; Pérez González, Pablo GuillermoWe present results from the KMOS LENsing Survey (KLENS), which is exploiting gravitational lensing to study the kinematics of 24 star -forming galaxies at 1.4 < z < 3.5 with a median mass of log(M-*/M-circle dot) = 9.6 and a median star formation rate (SFR) of 7.5 M-circle dot yr(-1). We find that 25% of these low mass/low SFR galaxies are rotation -dominated, while the majority of our sample shows no velocity gradient. When combining our data with other surveys, we find that the fraction of rotation -dominated galaxies increases with the stellar mass, and decreases for galaxies with a positive offset from the main sequence (higher specific star formation rate). We also investigate the evolution of the intrinsic velocity dispersion, sigma(0), as a function of the redshift, z, and stellar mass, M-*, assuming galaxies in quasi-equilibrium (Toomre Q parameter equal to 1). From the z -sigma(0) relation, we find that the redshift evolution of the velocity dispersion is mostly expected for massive galaxies (log(M-*/M-circle dot) > 10). We derive a M* - sigma(0) relation, using the Tully Fisher relation, which highlights that a different evolution of the velocity dispersion is expected depending on the stellar mass, with lower velocity dispersions for lower masses, and an increase for higher masses, stronger at higher redshift. The observed velocity dispersions from this work and from comparison samples spanning 0 < z < 3.5 appear to follow this relation, except at higher redshift (z > 2), where we observe higher velocity dispersions for low masses (log(M-*/M-circle dot) similar to 9.6) and lower velocity dispersions for high masses (log(M-*/M-circle dot) similar to 10.9) than expected. This discrepancy could, for instance, suggest that galaxies at high redshift do not satisfy the stability criterion, or that the adopted parametrization of the specific star formation rate and molecular properties fail at high redshift.Item The AGN, star-forming, and morphological properties of luminous ir-bright/optically-faint galaxies(Astrophysical journal, 2010) Donley, J. L.; Rieke, G. H.; Alexander, D. M.; Egami, E.; Pérez González, Pablo GuillermoWe present the active galactic nucleus (AGN), star-forming, and morphological properties of a sample of 13 MIR-luminous (∫_24 700 μJy) IR-bright/optically-faint galaxies (IRBGs, ∫_24/f_R≲ 1000). While these z ∼ 2 sources were drawn from deep Chandra fields with >200 ks X-ray coverage, only seven are formally detected in the X-ray and four lack X-ray emission at even the 2σ level. Spitzer InfraRed Spectrograph (IRS) spectra, however, confirm that all of the sources are AGN-dominated in the mid-IR, although half have detectable polycyclic aromatic hydrocarbon (PAH) emission responsible for ∼25% of their mid-infrared flux density. When combined with other samples, this indicates that at least 30%–40% of luminous IRBGs have star formation rates in the ultraluminous infrared galaxy (ULIRG) range (∼100–2000 M_⨀ yr^−1). X-ray hardness ratios and MIR to X-ray luminosity ratios indicate that all members of the sample contain heavily X-ray obscured AGNs, 80% of which are candidates to be Compton thick. Furthermore, the mean X-ray luminosity of the sample, log L_2–10 keV(erg s^−1) ∼44.6, indicates that these IRBGs are Type 2 QSOs, at least from the X-ray perspective. While those sources most heavily obscured in the X-ray are also those most likely to display strong silicate absorption in the mid-IR, silicate absorption does not always accompany X-ray obscuration. Finally, ∼70% of the IRBGs are merger candidates, a rate consistent with that of sub-mm galaxies (SMGs), although SMGs appear to be physically larger than IRBGs. These characteristics are consistent with the proposal that these objects represent a later, AGN-dominated, and more relaxed evolutionary stage following soon after the star-formation-dominated one represented by the SMGs.Item Testing diagnostics of nuclear activity and star formation in galaxies at z > 1(Astrophysical journal letters, 2013) Trump, Jonathan R.; Konidaris, Nicholas P.; Barro, Guillermo; Koo, David C.; Kocevski, Dale D.; Juneau, Stephanie; Weiner, Benjamin J.; Faber, S. M.; McLean, Ian S.; Yan, Renbin; Pérez González, Pablo Guillermo; Villar, VictorWe present some of the first science data with the new Keck/MOSFIRE instrument to test the effectiveness of different AGN/SF diagnostics at z ~ 1.5. MOSFIRE spectra were obtained in three H-band multi-slit masks in the GOODS-S field, resulting in 2 hr exposures of 36 emission-line galaxies. We compare X-ray data with the traditional emission-line ratio diagnostics and the alternative mass-excitation and color-excitation diagrams, combining new MOSFIRE infrared data with previous HST/WFC3 infrared spectra (from the 3D-HST survey) and multiwavelength photometry. We demonstrate that a high [O III]/Hβ ratio is insufficient as an active galactic nucleus (AGN) indicator at z > 1. For the four X-ray-detected galaxies, the classic diagnostics ([O III]/Hβ versus [N II]/Hα and [S II]/Hα) remain consistent with X-ray AGN/SF classification. The X-ray data also suggest that "composite" galaxies (with intermediate AGN/SF classification) host bona fide AGNs. Nearly ~2/3 of the z ~ 1.5 emission-line galaxies have nuclear activity detected by either X-rays or the classic diagnostics. Compared to the X-ray and line ratio classifications, the mass-excitation method remains effective at z > 1, but we show that the color-excitation method requires a new calibration to successfully identify AGNs at these redshifts.Item Molecular clouds in the Cosmic Snake normal star-forming galaxy 8 billion years ago(Nature astronomy, 2019) Pérez González, Pablo GuillermoThe cold molecular gas in contemporary galaxies is structured in discrete cloud complexes. These giant molecular clouds (GMCs), with 10^(4) –10^(7) solar masses (M⊙) and radii of 5–100 parsecs, are the seeds of star formation1 . Highlighting the molecular gas structure at such small scales in distant galaxies is observationally challenging. Only a handful of molecular clouds were reported in two extreme submillimetre galaxies at high redshift(2-4) . Here we search for GMCs in a typical Milky Way progenitor at z=1.036. Using the Atacama Large Millimeter/submillimeter Array (ALMA), we mapped the CO(4–3) emission of this gravitationally lensed galaxy at high resolution, reading down to 30 parsecs, which is comparable to the resolution of CO observations of nearby galaxies(5). We identify 17 molecular clouds, characterized by masses, surface densities and supersonic turbulence all of which are 10–100 times higher than present-day analogues. These properties question the universality of GMCs(6) and suggest that GMCs inherit their properties from ambient interstellar medium. The measured cloud gas masses are similar to the masses of stellar clumps seen in the galaxy in comparable numbers(7) . This corroborates the formation of molecular clouds by fragmentation of distant turbulent galactic gas disks(8,9), which then turn into stellar clumps ubiquitously observed in galaxies at ‘cosmic noon’ (ref. 10).