Browsing by Author "Bruzual, Gustavo"

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    Modelling H2 and its effects on star formation using a joint implementation of gadget-3 and KROME
    (2021) Sillero, Emanuel; Tissera, Patricia B.; Lambas, Diego G.; Bovino, Stefano; Schleicher, Dominik R.; Grassi, Tommaso; Bruzual, Gustavo; Charlot, Stephane
    We present p-gadget3-k, an updated version of gadget-3, that incorporates the chemistry package krome. p-gadget3-k follows the hydrodynamical and chemical evolution of cosmic structures, incorporating the chemistry and cooling of H-2 and metal cooling in non-equilibrium. We performed different runs of the same ICs to assess the impact of various physical parameters and prescriptions, namely gas metallicity, molecular hydrogen formation on dust, star formation recipes including or not H-2 dependence, and the effects of numerical resolution. We find that the characteristics of the simulated systems, both globally and at kpc-scales, are in good agreement with several observable properties of molecular gas in star-forming galaxies. The surface density profiles of star formation rate (SFR) and H-2 are found to vary with the clumping factor and resolution. In agreement with previous results, the chemical enrichment of the gas component is found to be a key ingredient to model the formation and distribution of H-2 as a function of gas density and temperature. A star formation algorithm that takes into account the H-2 fraction together with a treatment for the local stellar radiation field improves the agreement with observed H-2 abundances over a wide range of gas densities and with the molecular Kennicutt-Schmidt law, implying a more realistic modelling of the star formation process.
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    Spectroscopy of NGC 4258 Globular Cluster Candidates: Membership Confirmation and Kinematics
    (2019) Gonzalez-Lopezlira, Rosa A.; Mayya, Y. D.; Loinard, Laurent; Alamo-Martinez, Karla; Heald, George; Georgiev, Iskren Y.; Ordenes-Briceno, Yasna; Lancon, Ariane; Lara-Lopez, Maritza A.; Lomeli-Nunez, Luis; Bruzual, Gustavo; Puzia, Thomas H.
    We present multiobject spectroscopic observations of 23 globular cluster candidates (GCCs) in the prototypical megamaser galaxy NGC 4258, carried out with the Optical System for Imaging and low-Intermediate-Resolution Integrated Spectroscopy instrument at the 10.4 m Gran Telescopio Canarias. The candidates have been selected based on the (u* - i') versus (i' - K-s) diagram, in the first application of the u*i'K-s, method to a spiral galaxy. In the spectroscopy presented here, 70% of the candidates are confirmed as globular clusters (GCs). Our results validate the efficiency of the u*i'K-s, method in the sparser GC systems of spirals, and given the downward correction to the total number of GCs, the agreement of the galaxy with the correlations between black hole mass and the total number and mass of GCs is actually improved. We find that the GCs, mostly metal-poor, corotate with the H I disk, even at large galactocentric distances.
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    The Relation between Globular Cluster Systems and Supermassive Black Holes in Spiral Galaxies. III. The Link to the M.-M * Correlation
    (2022) Gonzalez-Lopezlira, Rosa A.; Lomeli-Nunez, Luis; Ordenes-Briceno, Yasna; Loinard, Laurent; Gwyn, Stephen; Alamo-Martinez, Karla; Bruzual, Gustavo; Lancon, Ariane; Puzia, Thomas H.
    D We continue to explore the relationship between the total number of globular clusters (GCs), NGC, and the central black hole mass, M alpha, in spiral galaxies. We present here results for the Sab galaxies NGC 3368, NGC 4736 (M94), and NGC 4826 (M64), and the Sm galaxy NGC 4395. The GC candidate selection is based on the (u* - i cent) versus (i cent - Ks) color-color diagram, and i cent-band shape parameters. We determine the M alpha versus NGC correlation for these spirals, plus NGC 4258, NGC 253, M104, M81, M31, and the Milky Way. We also redetermine the correlation for the elliptical sample in Harris et al., with updated galaxy types from Sahu et al. Additionally, we derive the total stellar galaxy mass, M*, from its two-slope correlation with NGC, and fit M _ versus M* for both spirals and ellipticals. We obtain log M alpha. (1.01 +/- 0.13) log NGC for ellipticals, and log M alpha. (1.64 +/- 0.24) log NGC for latetype galaxies (LTGs). The linear M alpha versus NGC correlation in ellipticals could be due to statistical convergence through mergers, unlike the much steeper correlation for LTGs. However, in the M alpha versus total stellar mass (M*) parameter space, with M* derived from its correlation with NGC, M alpha. (1.48 +/- 0.18) log M* for ellipticals, and M alpha. (1.21 +/- 0.16) log M* for LTGs. The observed agreement between ellipticals and LTGs in this parameter space may imply that black holes and galaxies coevolve through calm accretion, active galactic nuclei feedback, and other secular processes.