Stellar Mass Star Formation Rate Research Articles

The First Combined Hα and Rest-UV Spectroscopic Probe of Galactic Outflows at High Redshift

We investigate the multiphase structure of gas flows in galaxies. We study 80 galaxies during the epoch of peak star formation (1.4 ≤ z ≤ 2.7) using data from the Keck/Low-Resolution Imaging Spectrometer (LRIS) and the Very Large Telescope/K-Band Multi-Object Spectrograph (KMOS). Our analysis provides a simultaneous probe of outflows using UV emission and absorption features and Hα emission. With this unprecedented data set, we examine the properties of gas flows estimated from LRIS and KMOS in relation to other galaxy properties, such as star formation rate (SFR), SFR surface density (ΣSFR), stellar mass (M *), and main-sequence offset (ΔMS). We find no strong correlations between outflow velocity measured from rest-UV line centroids and galaxy properties. However, we find that galaxies with detected outflows show higher averages in SFR, ΣSFR, and ΔMS than those lacking outflow detections, indicating a connection between outflow and galaxy properties. Furthermore, we find a lower average outflow velocity than previously reported, suggesting greater absorption at the systemic redshift of the galaxy. Finally, we detect outflows in 49% of our LRIS sample and 30% in the KMOS sample and find no significant correlation between outflow detection and inclination. These results may indicate that outflows are not collimated and that Hα outflows have a lower covering fraction than low-ionization interstellar absorption lines. Additionally, these tracers may be sensitive to different physical scales of outflow activity. A larger sample size with a wider dynamic range in galaxy properties is needed to further test this picture.

The SAGA Survey. IV. The Star Formation Properties of 101 Satellite Systems around Milky Way–mass Galaxies

Abstract We present the star-forming properties of 378 satellite galaxies around 101 Milky Way analogs in the Satellites Around Galactic Analogs (SAGA) Survey, focusing on the environmental processes that suppress or quench star formation. In the SAGA stellar mass range of 106−10 M ⊙, we present quenched fractions, star-forming rates, gas-phase metallicities, and gas content. The fraction of SAGA satellites that are quenched increases with decreasing stellar mass and shows significant system-to-system scatter. SAGA satellite quenched fractions are highest in the central 100 kpc of their hosts and decline out to the virial radius. Splitting by specific star formation rate (sSFR), the least star-forming satellite quartile follows the radial trend of the quenched population. The median sSFR of star-forming satellites increases with decreasing stellar mass and is roughly constant with projected radius. Star-forming SAGA satellites are consistent with the star formation rate–stellar mass relationship determined in the Local Volume, while the median gas-phase metallicity is higher and median H i gas mass is lower at all stellar masses. We investigate the dependence of the satellite quenched fraction on host properties. Quenched fractions are higher in systems with larger host halo mass, but this trend is only seen in the inner 100 kpc; we do not see significant trends with host color or star formation rate. Our results suggest that lower-mass satellites and satellites inside 100 kpc are more efficiently quenched in a Milky Way–like environment, with these processes acting sufficiently slowly to preserve a population of star-forming satellites at all stellar masses and projected radii.

The Nature of 500 micron Risers III: a small complete sample

ABSTRACT Herschel surveys have found large numbers of sources with red far-IR colours, and spectral energy distributions (SEDs) rising from 250 to 500 µm: 500 risers. The nature and role of these sources is not fully understood. We here present Submillimeter Array (SMA) interferometric imaging at 200 GHz of a complete sample of five 500 risers with F500 >44 mJy selected within a 4.5 deg2 region of the XMMLSS field. These observations can resolve the separate components of multiple sources and allow cross identification at other wavelengths using the extensive optical-to-IR data in this field. Of our five targets, we find that two are likely gravitationally lensed, two are multiple sources, and one an isolated single source. Photometric redshifts, using optical-to-IR data and far-IR/submm data, suggest they lie at redshifts $z \sim 2.5\!-\!3.5$. Star formation rates and stellar masses estimated from the SEDs show that the majority of our sources lie on the star-formation rate-stellar mass ‘main sequence’, though with outliers both above and below this relation. Of particular interest is our most multiple source, which consists of three submm emitters and one submm-undetected optical companion within a 7 arcsec region, all with photometric redshifts ∼3. One of the submm emitters in this group lies above the ‘main sequence’, while the optical companion lies well below the relation, and has an estimated stellar mass of $3.3 \pm 1.3 \times 10^{11}$ M$_{\odot }$. We suggest this object is a forming brightest cluster galaxy (BCG) in the process of accreting actively star forming companions.

MusE GAs FLOw and Wind (MEGAFLOW)

Absorption line spectroscopy using background quasars can provide strong constraints on galactic outflows. In this paper we investigate possible scaling relations between outflow properties, namely outflow velocity Vout, mass ejection rate Ṁout, and mass loading factor η, and the host galaxy properties, such as star formation rate (SFR), SFR surface density, redshift, and stellar mass, using galactic outflows probed by background quasars from MEGAFLOW and other surveys. We find that Vout (η) is (anti-)correlated with SFR and SFR surface density. We extend the formalism of momentum-driven outflows from a previous study to show that it applies not only to “down-the-barrel” studies, but also to winds probed by background quasars, suggesting a possible universal wind formalism. Under this formalism, we find a clear distinction between strong and weak outflows where strong outflows seem to have tighter correlations with galaxy properties (SFR or galaxy stellar mass) than weak outflows.

A comparative study of the fundamental metallicity relation

Aims. We aim to investigate the influences on the evolution of the fundamental metallicity relation of different selection criteria. Methods. We used 5 487 star-forming galaxies at a median redshift of z ≈ 0.63 extracted from the VIMOS Public Extragalactic Redshift Survey (VIPERS) and 143 774 comparison galaxies in the local Universe from the GALEX-SDSS-WISE Legacy Catalog. We employed two families of methods: parametric and nonparametric. In the parametric approaches, we compared the fundamental metallicity relation projections plagued by observational biases on differently constructed control samples at various redshifts. Then, we compare the metallicity difference between different redshifts in stellar mass-star formation rate bins. In the nonparametric approach, we related the metallicity and the normalized specific star formation rate (sSFR). To compare galaxies with the same physical properties, we normalized the sSFR of our samples according to the median value at median redshift z ≈ 0.09. Then, the galaxies with the same distance from the star-forming main sequence at their respective redshifts were compared when the sSFR is normalized according to the expected values from their respective star-forming main sequences. Results. The methodologies implemented to construct fair, complete samples for studying the mass-metallicity relation and the fundamental metallicity relation produced consistent results showing a small but still statistically significant evolution of both relations up to z ≈ 0.63. In particular, we observed a systematic trend where the median metallicity of the sample at z = 0.63 is lower than that of the local sample at the same stellar mass and star formation rate. The average difference in the metallicity of the low and intermediate redshifts is approximately 1.8 times the metallicity standard deviation of the median of the intermediate redshift sample in stellar mass-star formation rate bins. We confirmed this result using the Kolmogorov-Smirnov test. When we applied the stellar mass-completeness criterion to catalogs, the metallicity difference in redshifts decreased to approximately 0.96 times the metallicity standard deviation of the median, and thus it was not statistically significant. The limited area of the FMR surface explored once the stellar mass-completeness criterion is applied might dominate this difference reduction, leaving out the area where the difference between the two samples is the highest. A careful reading of the results and their underlying selection criteria is crucial in studies of the mass-metallicity and fundamental metallicity relations. Conclusions. When studying the mass-metallicity and fundamental metallicity relations, we recommend using the nonparametric approach, which provides similar results compared to parametric prescriptions, is easier to use, and is clear to interpret. The nonparametric methodology provides a convenient way to compare physical properties, with a smaller impact on observational selection biases.

The Art of Measuring Physical Parameters in Galaxies: A Critical Assessment of Spectral Energy Distribution Fitting Techniques

The study of galaxy evolution hinges on our ability to interpret multiwavelength galaxy observations in terms of their physical properties. To do this, we rely on spectral energy distribution (SED) models, which allow us to infer physical parameters from spectrophotometric data. In recent years, thanks to wide and deep multiwave band galaxy surveys, the volume of high-quality data have significantly increased. Alongside the increased data, algorithms performing SED fitting have improved, including better modeling prescriptions, newer templates, and more extensive sampling in wavelength space. We present a comprehensive analysis of different SED-fitting codes including their methods and output with the aim of measuring the uncertainties caused by the modeling assumptions. We apply 14 of the most commonly used SED-fitting codes on samples from the CANDELS photometric catalogs at z ∼ 1 and z ∼ 3. We find agreement on the stellar mass, while we observe some discrepancies in the star formation rate (SFR) and dust-attenuation results. To explore the differences and biases among the codes, we explore the impact of the various modeling assumptions as they are set in the codes (e.g., star formation histories, nebular, dust and active galactic nucleus models) on the derived stellar masses, SFRs, and A V values. We then assess the difference among the codes on the SFR–stellar mass relation and we measure the contribution to the uncertainties by the modeling choices (i.e., the modeling uncertainties) in stellar mass (∼0.1 dex), SFR (∼0.3 dex), and dust attenuation (∼0.3 mag). Finally, we present some resources summarizing best practices in SED fitting.

The Roles of Morphology and Environment on the Star Formation Rate–Stellar Mass Relation in COSMOS from 0 < z < 3.5

We investigate the relationship between environment, morphology, and the star formation rate (SFR)–stellar mass relation derived from a sample of star-forming (SF) galaxies (commonly referred to as the “star formation main sequence”, SFMS) in the COSMOS field from 0 < z < 3.5. We constructed and fit the far-UV–far-IR spectral energy distributions of our stellar-mass-selected sample of 111,537 galaxies with stellar and dust emission models using the public packages MAGPHYS and SED3FIT. From the best-fit parameter estimates, we construct the SFR–stellar mass relation as a function of redshift, local environment, NUVrJ color diagnostics, and morphology. We find that the shape of the main sequence derived from our color–color and specific-star-formation-rate-selected SF galaxy population, including the turnover at high stellar mass, does not exhibit an environmental dependence at any redshift from 0 < z < 3.5. We investigate the role of morphology in the high-mass end of the SFMS to determine whether bulge growth is driving the high-mass turnover. We find that SF galaxies experience this turnover independent of bulge-to-total ratio, strengthening the case that the turnover is due to the disk component’s specific SFR evolving with stellar mass rather than bulge growth.

Constraining galactic baryon cycle using the galaxy stellar-to-halo mass relations

ABSTRACT Galaxies display several well-behaved scaling relations between their properties, such as the star formation rate–stellar mass relation (the main sequence, MS) and the stellar mass–halo mass relation (SHMR). In principle, these scaling relations could imply different star formation histories (SFHs) of galaxies and different constraints on galaxy formation physics. In this paper, we derive the SFHs of galaxies by assuming that they always follow the SHMRs at different redshifts and use an empirical model to constrain key processes in their baryon cycle. It is found that, besides cold accretion due to halo growth, outflow of gas produced by stellar feedback has to be recycled to sustain the derived SFHs of galaxies. The recycled fraction is strongly affected by the baryon fraction in accreted low-mass haloes and the mass loading factor that quantifies the ratio between the galactic outflow rate and star formation rate. Our fiducial model predicts that around 20–60 per cent of outflow is recycled in $\sim 0.5\!-\!4\, \mathrm{Gyr}$, while simulations predict a slightly higher recycle fraction and a lower recycle time. We argue that strong constraints on the baryon cycle process can be obtained from future observation of the circum-galactic medium (CGM) of galaxies, such as the gas cooling rate of CGM. We also find that the implied SFHs from the SHMRs indicate that galaxies stay on the MS only for part of their lifetimes. Our model reproduces the evolution of the mass–metallicity relation as well.

The dispersion measure of Fast Radio Bursts host galaxies: estimation from cosmological simulations

ABSTRACT The dispersion measure (DM) of fast radio burst (FRB) encodes important information such as its distance, properties of intervening medium. Based on simulations in the Illustris and IllustrisTNG projects, we analyse the DM of FRBs contributed by the interstellar medium and circumgalactic medium in the hosts, DMhost. We explore two population models – tracing the star formation rate (SFR) and the stellar mass, i.e. young and old progenitors, respectively. The distribution of DMhost shows significant differences at z = 0 between two populations: the stellar mass model exhibits an excess at the low-DM end with respect to the SFR model. The SFR (stellar mass) model has a median value of 179 (63) pc cm−3 for galaxies with $M_*=10^{8\!-\!13}\, \mathrm{M}_{\odot }$ in the TNG100-1. Galaxies in the Illustris-1 have a much smaller DMhost. The distributions of DMhost deviate from lognormal function for both models. Furthermore, two populations differ moderately in the spatial offset from host galaxy’s centre in the stellar mass function of hosts. DMhost increases with the stellar mass of hosts when $M_* &amp;lt; 10^{10.5}\, \mathrm{M}_{\odot }$, and fluctuate at higher mass. At 0 &amp;lt; z &amp;lt; 2, DMhost increases with redshift. The differences in DMhost between two populations declines with increasing redshift. With more localized events available in the future, statistics such as DMhost, the offset from galaxy centre, and the stellar mass function of hosts will be of great helpful to ascertain the origin of FRB. Meanwhile, statistics of DMhost of localized FRB events could help to constrain the baryon physics models in galaxy evolution.

Peculiar Black Hole Accretion Rates in AGN with Highest Star Formation Rates in the Universe

Pouliasis et al. explored star formation rates, black hole accretion rates, and stellar mass of active galaxies at redshift above 3.5, uncovering a leveling off of the star formation rate at high stellar mass, which they consider to be evidence of AGN feedback. Their data shows that as AGN approach the flattening of the curve in the star formation rate—stellar mass plane, the accretion rates begin to drop. We describe the nature of the AGN feedback responsible for this in terms of powerful FRII jets enhancing star formation rates but eventually also triggering a shift in accretion from near-Eddington rates to advection dominated. These systems are on the cusp of a dramatic transition where the active galaxy goes from strong enhancement to large suppression of star formation in a way that produces the steeper slope for radio AGN at low redshift compared to radio AGN at higher redshift and to jetless AGN. We argue, therefore, that the data of Pouliasis et al. constitute the high redshift objects predicted by Singh et al. that connect to the low redshift behavior of radio AGN shown in Comerford et al.

Galaxy formation in the Santa Cruz semi-analytic model compared with IllustrisTNG – I. Galaxy scaling relations, dispersions, and residuals at z = 0

ABSTRACT We present the first results from applying the Santa Cruz semi-analytic model (SAM) for galaxy formation on merger trees extracted from a dark matter only version of the IllustrisTNG (TNG) simulations. We carry out a statistical comparison between the predictions of the Santa Cruz SAM and TNG for a subset of central galaxy properties at z = 0 with a focus on stellar mass, cold and hot gas mass, star formation rate (SFR), and black hole (BH) mass. We find fairly good agreement between the mean predictions of the two methods for stellar mass functions and the stellar mass versus halo mass (SMHM) relation, and qualitatively good agreement between the SFR or cold gas mass versus stellar mass relation and quenched fraction as a function of stellar mass There are greater differences between the predictions for hot (circumgalactic) gas mass and BH mass as a function of halo mass. Going beyond the mean relations, we also compare the dispersion in the predicted scaling relations, and the correlation in residuals on a halo-by-halo basis between halo mass and galaxy property scaling relations. Intriguingly, we find similar correlations between residuals in SMHM in the SAM and in TNG, suggesting that these relations may be shaped by similar physical processes. Other scaling relations do not show significant correlations in the residuals, indicating that the physics implementations in the SAM and TNG are significantly different.

The Distribution of Radio Quiet Active Galactic Nuclei in the Star Formation Rate-stellar Mass Plane

That active galactic nuclei (AGN) with jets can alternately enhance as well as suppress star formation rates, explains the location and slope of radio loud AGN on the star formation rate—stellar mass plane. Here, we explore 860 type 1 and 2 AGN at z < 0.2 from the ROSAT-2RXS survey in order to understand both different location and lower slopes for non-jetted AGN in the star formation rate—stellar mass plane. We describe the nature of these differences in terms of different degrees of black hole feedback, with relatively weak negative feedback from non-jetted AGN compared to both relatively strong positive and negative feedback from jetted AGN. The validity of these ideas brings us a step closer towards understanding the black hole scaling relations across space and time.

Stellar Mass-to-light Ratios: Composite Bulge+Disk Models and the Baryonic Tully–Fisher Relation

Abstract We present stellar population models to calculate the mass-to-light ratio (ϒ*) based on galaxies’ colors ranging from GALEX far-UV to Spitzer IRAC1 at 3.6 μm. We present a new composite bulge+disk ϒ* model that considers the varying contribution from bulges and disks based on their optical and near-IR colors. Using these colors, we build plausible star formation histories and chemical enrichment scenarios based on the star formation rate–stellar mass and mass–metallicity correlations for star-forming galaxies. The most accurate prescription is to use the actual colors for the bulge and disk components to constrain ϒ*; however, a reasonable bulge+disk model plus total color only introduces 5% more uncertainty. Full bulge+disk ϒ* prescriptions applied to the baryonic Tully–Fisher relation improve the linearity of the correlation, increase the slope, and reduce the total scatter by 4%.

The Black Hole-star Formation Connection Over Cosmic Time

Observations at low redshift have begun to tease out the star formation rate in active galaxies (AGN), which marks the beginning of the black hole-star formation connection over cosmic time. Star formation appears to depend on AGN type, cluster richness, and black hole accretion, but in ways that are not direct and have yet to be understood. Much of the confusion is that while some AGN appear to enhance star formation, others seem to suppress it. By implementing simplified, yet informed assumptions about AGN feedback on star formation, we show how AGN with jets might be dominated by two phases in which star formation is first enhanced, then suppressed. With this new element incorporated into our model, we make sense of radio and quasar mode behavior in the star formation rate–stellar mass (SFR-SM) plane for AGN. Due to jet feedback on star formation, jetted AGN tends to move upwards and rightward in the SFR-SM plane and then downward and to the right, past both the star-forming main sequence as well as the radio-quiet AGN. This picture allows us to predict the black hole connection to star formation as a function of the environment over the history of the universe.

The spatially resolved view of star formation in galaxy clusters

AbstractIntegral field spectroscopic studies of galaxies in dense environments, such as clusters and groups of galaxies, have provided new insights for understanding how star formation proceeds, and quenches. I present the spatially resolved view of the star formation activity and its link with the multiphase gas in cluster galaxies based on MUSE and multi-wavelength data of the GASP survey. I discuss the link among the different scales (i.e. the link between the spatially resolved and the global star formation rate-stellar mass relation), the spatially resolved signatures and the quenching histories of jellyfish (progenitors) and post-starburst (descendants) galaxies in clusters. Finally, I discuss the multi-wavelength view of star-forming clumps both in galaxy disks and in the tails of stripped gas.

The H α star formation main sequence in cluster and field galaxies at z ∼ 1.6

ABSTRACT We calculate H α-based star formation rates and determine the star formation rate–stellar mass relation for members of three Spitzer Adaptation of the Red-Sequence Cluster Survey (SpARCS) clusters at z ∼ 1.6 and serendipitously identified field galaxies at similar redshifts to the clusters. We find similar star formation rates in cluster and field galaxies throughout our range of stellar masses. The results are comparable to those seen in other clusters at similar redshifts, and consistent with our previous photometric evidence for little quenching activity in clusters. One possible explanation for our results is that galaxies in our z ∼ 1.6 clusters have been accreted too recently to show signs of environmental quenching. It is also possible that the clusters are not yet dynamically mature enough to produce important environmental quenching effects shown to be important at low redshift, such as ram-pressure stripping or harassment.

The Roles of Mass and Environment in the Quenching of Galaxies. II.

Abstract We take advantage of an analytic model of galaxy formation coupled to the merger tree of an N-body simulation to study the roles of environment and stellar mass in the quenching of galaxies. The model has been originally set in order to provide the observed evolution of the stellar mass function as well as reasonable predictions of the star formation rate–stellar mass relation, from high redshift to the present time. We analyze the stellar mass and environmental quenching efficiencies and their dependence on stellar mass, halo mass (taken as a proxy for the environment), and redshift. Our analysis shows that the two quenching efficiencies are dependent on redshift and stellar and halo mass, and that the halo mass is also a good proxy for the environment. The environmental quenching increases with decreasing redshift and is inefficient below log M * ∼ 9.5, reaches the maximum value at log M * ∼ 10.5, and decreases again, becoming poorly efficient at very high stellar mass (log M * ≳ 11.5). Central and satellites galaxies are mass quenched differently: for the former, the quenching efficiency depends very weakly on redshift but strongly on stellar mass; for the latter, it strongly depends on both stellar mass and redshift in the range . According to the most recent observational results, we find that the two quenching efficiencies are not separable: intermediate-mass galaxies, as well as intermediate/massive galaxies in more massive halos, are environmentally quenched faster. At stellar masses lower than log M * ≲ 9.5, both quenching mechanisms become inefficient, independently of the redshift.

Significance of bar quenching in the global quenching of star formation

The suppression of star formation in the inner kiloparsec regions of barred disk galaxies due to the action of bars is known as bar quenching. We investigate here the significance of bar quenching in the global quenching of star formation in the barred galaxies and their transformation to passive galaxies in the local Universe. We do this by measuring the offset of quenched barred galaxies from star-forming main sequence galaxies in the star formation rate-stellar mass plane and comparing it with the length of the bar, which is considered as a proxy of bar quenching. We constructed the star formation rate-stellar mass plane of 2885 local Universe face-on strong barred disk galaxies (z &lt; 0.06) identified by Galaxy Zoo. The barred disk galaxies studied here fall on the star formation main sequence relation with a significant scatter for galaxies above stellar mass 1010.2M⊙. We found that 34.97% galaxies are within the intrinsic scatter (0.3 dex) of the main sequence relation, with a starburst population of 10.78% (above the 0.3 dex) and a quenched population of 54.25% (below the −0.3 dex) of the total barred disk galaxies in our sample. Significant neutral hydrogen (MHI&gt; 109M⊙with logMHI/M⋆∼ −1.0 to −0.5) is detected in the quenched barred galaxies with a similar gas content to that of the star-forming barred galaxies. We found that the offset of the quenched barred galaxies from the main sequence relation is not dependent on the length of the stellar bar. This implies that the bar quenching may not contribute significantly to the global quenching of star formation in barred galaxies. However, this observed result could also be due to other factors such as the dissolution of bars over time after star formation quenching, the effect of other quenching processes acting simultaneously, and/or the effects of environment.

SDSS-IV MaNGA: effects of morphology in the global and local star formation main sequences

ABSTRACT We study the global star formation rate (SFR) versus stellar mass (M*) correlation, and the spatially resolved SFR surface density (ΣSFR) versus stellar mass surface density (Σ*) correlation, in a sample of ∼2000 galaxies from the MaNGA MPL-5 survey. We classify galaxies and spatially resolved areas into star forming and retired according to their ionization processes. We confirm the existence of a star-forming main sequence (SFMS) for galaxies and spatially resolved areas, and show that they have the same nature, with the global as a consequence of the local one. The latter presents a bend below a limit Σ* value, ≈3 × 107 M$\odot$ kpc−2, which is not physical. Using only star-forming areas (SFAs) above this limit, a slope and a scatter of ≈1 and ≈0.27 dex are determined. The retired galaxies/areas strongly segregate from their respective SFMSs, by ∼−1.5 dex on average. We explore how the global/local SFMSs depend on galaxy morphology, finding that for star-forming galaxies and SFAs, there is a trend to lower values of star formation activity with earlier morphological types, which is more pronounced for the local SFMS. The morphology not only affects the global SFR due to the diminish of SFAs with earlier types, but also affects the local SF process. Our results suggest that the local SF at all radii is established by some universal mechanism partially modulated by morphology. Morphology seems to be connected to the slow aging and sharp decline of the SF process, and on its own it may depend on other properties as the environment.

The star formation activity of IllustrisTNG galaxies: main sequence, UVJ diagram, quenched fractions, and systematics

Abstract We select galaxies from the IllustrisTNG hydrodynamical simulations ($M_{\rm stars}\gt 10^9 \, {\rm M}_\odot$ at 0 ≤ z ≤ 2) and characterize the shapes and evolutions of their UVJ and star formation rate–stellar mass (SFR–Mstars) diagrams. We quantify the systematic uncertainties related to different criteria to classify star-forming versus quiescent galaxies, different SFR estimates, and by accounting for the star formation measured within different physical apertures. The TNG model returns the observed features of the UVJ diagram at z ≤ 2, with a clear separation between two classes of galaxies. It also returns a tight star-forming main sequence (MS) for $M_{\rm stars}\lt 10^{10.5} \, ({\rm M}_\odot)$ with a ∼0.3 dex scatter at z ∼ 0 in our fiducial choices. If a UVJ-based cut is adopted, the TNG MS exhibits a downwardly bending at stellar masses of about 1010.5−10.7 M⊙. Moreover, the model predicts that ${\sim }80\, (50)$ per cent of 1010.5−11 M⊙ galaxies at z = 0 (z = 2) are quiescent and the numbers of quenched galaxies at intermediate redshifts and high masses are in better agreement with observational estimates than previous models. However, shorter SFR-averaging time-scales imply higher normalizations and scatter of the MS, while smaller apertures lead to underestimating the galaxy SFRs: overall we estimate the inspected systematic uncertainties to sum up to about 0.2−0.3 dex in the locus of the MS and to about 15 percentage points in the fraction of quenched galaxies. While TNG colour distributions are clearly bimodal, this is not the case for the SFR logarithmic distributions in bins of stellar mass (SFR ≳ 10−3 M⊙yr−1). Finally, the slope and z = 0 normalization of the TNG MS are consistent with observational findings; however, the locus of the TNG MS remains lower by about 0.2−0.5 dex at 0.75 ≤ z &amp;lt; 2 than the available observational estimates taken at face value.