Dissecting Nearby Galaxies with piXedfit. II. Spatially Resolved Scaling Relations among Stars, Dust, and Gas

Abstract

We study spatially resolved scaling relations among stars, dust, and gas in ten nearby spiral galaxies. In a preceding paper, we have derived spatially resolved properties of the stellar population and dust by a panchromatic spectral energy distribution fitting using piXedfit. Now, we investigate resolved star formation ( Σ H 2 –ΣSFR–Σ*) and dust scaling relations. While the relations with all subgalactic regions of the galaxies are reasonably tight (σ ≲ 0.3 dex), we find that most of the scaling relations exhibit galaxy-to-galaxy variations in normalization and shape. Only two relations of Σdust–Σgas and Σdust– Σ H 2 do not show noticeable galaxy-to-galaxy variations among our sample galaxies. We further investigate the correlations among the scaling relations. We find significant correlations among the normalization of the Σ H 2 –ΣSFR–Σ* relations, which suggest that the galaxies with higher levels of resolved H2 fraction ( f H 2 ) tend to have higher levels of resolved star formation efficiency (SFE) and specific star formation rate (sSFR). We also observe that the galaxies with higher levels of resolved dust-to-stellar mass ratios tend to have higher levels of resolved sSFR, SFE, and f H 2 . Moreover, we find that the galaxies with higher global sSFR and less compact morphology tend to have higher levels of the resolved sSFR, SFE, and f H 2 , which can explain the variations in the normalization of the Σ H 2 –ΣSFR–Σ* relationships. Overall, we observe indications of the contributions of both global and local factors in governing the star formation process in galaxies.

The resolved scaling relations in DustPedia: Zooming in on the local Universe

“…If small-scale processes drive the SF and a large set of SRs at different scales, this does not mean that also global processes and global galaxy properties do not play a role (see, e.g., Abdurro'uf et al 2022). Galaxies with strong bars, interactions between galaxies and with the environment, mergers, gas inflows/outflows, and/or the presence of an AGN can affect the gas fraction and therefore the SF of the entire galaxy (e.g., Casasola et al 2004;Poggianti et al 2017;Sánchez et al 2018;Sánchez 2020;Mancillas et al 2019).…”

“…2010; CO: HERACLES-IRAM 30 m, Leroy et al 2009;ALLSMOG: Cicone et al 2017;COMING, Sorai et al 2019; Hi: VLA THINGS survey, Walter et al 2008;xGASS Catinella et al 2018) and the detailed work of homogenization of preexistent data to collect large amounts of coherent observations (e.g., DustPedia, Davies et al 2017), it is now possible to investigate the main SRs also on the subgalactic scale. In the literature one refers to such subgalactic SRs, typically at kiloparsec scales, as resolved SRs (e.g., Viaene et al 2014;Roychowdhury et al 2015;Barrera-Ballesteros et al 2016Cano-Díaz et al 2016;Hsieh et al 2017;Pan et al 2018;Cano-Díaz et al 2019;Lin et al 2019;Vulcani et al 2019;Enia et al 2020;Morselli et al 2020;Ellison et al 2021;Sánchez et al 2021;Abdurro'uf et al 2022;Baker et al 2022). Most of these works focused on the SF relations, that is those between stellar mass surface density (Σ star ), molecular gas mass surface density (Σ H2 ), and SFR surface density (Σ SFR ).…”

Spatially Resolved Stellar Populations of 0.3 < z < 6.0 Galaxies in WHL 0137–08 and MACS 0647+70 Clusters as Revealed by JWST: How Do Galaxies Grow and Quench over Cosmic Time?

“…This includes the spatially resolved SFMS (rSFMS), a relationship between the SFR surface density (Σ SFR ) and M * surface density (Σ * ), a local analog of the global SFMS (e.g., Sánchez et al 2013;Wuyts et al 2013;Cano-Díaz et al 2016;Abdurro'uf & Akiyama 2017;Hsieh et al 2017;Abdurro'uf & Akiyama 2018;Lin et al 2019;Enia et al 2020). Recent studies found that the rSFMS relation (and hence the global SFMS) originated from two more fundamental relations on kiloparsec scales: the resolved Kennicutt-Schmidt (Σ SFR versus H 2 mass surface density; S H 2 ) and molecular gas main-sequence relations (Σ * versus S H 2 ) (e.g., Lin et al 2019;Morselli et al 2020;Abdurro'uf et al 2022b;Baker et al 2022). This emphasizes the necessity of studying the spatially resolved properties of galaxies.…”

Colour gradients of low-redshift galaxies in the DESI Legacy Imaging Survey

“…Template fits to spectra (or to well-sampled broad-band SEDs, e.g. Abdurro'uf et al 2022) can break degeneracies between the effects of age, metallicity and dust on the colour of stellar populations. In principle, spatially resolved spectroscopy can be used to measure stellar population gradients directly, and therefore help both to explain the colour gradient trends we observe and to enable more straightforward comparisons with simulations.…”

“…Results from previous statistical studies of colour gradients in the low redshift galaxy population, including Peletier et al (1990); De Jong (1996); La Barbera et al (2005); Tortora et al (2010) and Gonzalez-Perez et al (2011), are broadly consistent with the current consensus understanding of galaxy formation (we discuss this in more detail in Section 5). However, the effects of age, metallicity and dust on the broadband colours of stellar populations are notoriously degenerate, which greatly limits more detailed inferences about galaxy formation based on resolved photometric data alone (although see Abdurro'uf et al 2022). In contrast, fits of population synthesis templates to spatially resolved spectroscopy can provide much stronger constraints on the underlying stellar populations, and hence allow trends in the distribution of age, metallicity and dust content to be measured more directly.…”