Mario Santos

The Baldwin, Philips, & Terlevich diagram of [O III]/Hβ vs. [N II]/Hα (hereafter N2-BPT) has long been used as a tool for classifying galaxies based on the dominant source of ionizing radiation. Recent observations have demonstrated that galaxies at z∼2 reside offset from local galaxies in the N2-BPT space. In this paper, we conduct a series of controlled numerical …

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We present the evolution of the star-formation dispersion – stellar mass relation (σSFR-M⋆) in the DEVILS D10 region using new measurements derived using the ProSpect spectral energy distribution fitting code. We find that σSFR-M⋆ shows the characteristic ‘U-shape’ at intermediate stellar masses from 0.1<z<0.7 for a number of metrics, including using the deconvolved intrinsic dispersion. A physical …

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Using the state-of-the-art suite of hydrodynamic simulations Simba, as well as its dark-matter-only counterpart, we study the impact of the presence of baryons and of different stellar/AGN feedback mechanisms on large-scale structure, halo density profiles, and on the abundance of different baryonic phases within halos and in the intergalactic medium (IGM). The unified picture that …

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We study the variation of the gravitational Newton’s constant on cosmological scales in scalar-tensor theories of gravity. We focus on the simplest models of scalar-tensor theories with a coupling to the Ricci scalar of the form F(σ)=N2pl+ξσ2, such as extended Jordan-Brans-Dicke (Npl=0), or a non-minimally coupled scalar field with Npl=Mpl, which permits the gravitational constant to vary …

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21cm intensity mapping experiments are bringing an influx of high spectral resolution observational data in the ∼100 MHz −1 GHz regime. We use pilot 971−1075 MHz data from MeerKAT in single-dish mode, recently used to test the calibration and data reduction scheme of the upcoming MeerKLASS survey, to probe the spectral index of diffuse synchrotron emission below 1 GHz within 145∘<α<180∘, −1∘<δ<8∘. Through …

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Understanding the halo-galaxy connection is fundamental in order to improve our knowledge on the nature and properties of dark matter. In this work we build a model that infers the mass of a halo given the positions, velocities, stellar masses, and radii of the galaxies it hosts. In order to capture information from correlations among …

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Observations of cold molecular gas reservoirs are critical for understanding the shutdown of star formation in massive galaxies. While dust continuum is an efficient and affordable tracer, this method relies upon the assumption of a “normal” molecular-gas to dust mass ratio, δGDR, typically of order one hundred. Recent null detections of quiescent galaxies in deep dust …

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