Subscribe to the gold package and get unlimited access to Shamra Academy
Register a new userSDSS-IV MaNGA: The kinematic-morphology of galaxies on the mass vs star-formation relation in different environments
73
0
0.0
(
0
)
Ask ChatGPT about the research
No Arabic abstract
We study the link between the kinematic-morphology of galaxies, as inferred from integral-field stellar kinematics, and their relation between mass and star formation rate (SFR). Our sample consists of $sim 3200$ galaxies with integral-field spectroscopic data from the MaNGA survey with available determinations of their effective stellar angular momentum within the half-light radius $lambda_{R_e}$. We find that for star-forming galaxies, namely along the star formation main sequence (SFMS), the $lambda_{R_e}$ values remain large and almost unchanged over about two orders of magnitude in stellar mass, with the exception of the lowest masses $mathcal{M}_{star}lesssim2times10^{9} mathcal{M}_{odot}$, where $lambda_{R_e}$ slightly decreases. The SFMS is dominated by spiral galaxies with small bulges. Below the SFMS, but above the characteristic stellar mass $mathcal{M}_{rm crit}approx2times10^{11} mathcal{M}_{odot}$, there is a sharp decrease in $lambda_{R_e}$ with decreasing star formation rate: massive galaxies well below the SFMS are mainly slow-rotator early-type galaxies, namely genuinely spheroidal galaxies without disks. Below the SFMS and below $mathcal{M}_{rm crit}$ the decrease of $lambda_{R_e}$ with decreasing SFR becomes modest or nearly absent: low-mass galaxies well below the SFMS, are fast-rotator early-type galaxies, and contain fast-rotating stellar disks like their star-forming counterparts. We also find a small but clear environmental dependence for the massive galaxies: in the mass range $10^{10.9}-10^{11.5} mathcal{M}_{odot}$, galaxies in rich groups or denser regions or classified as central galaxies have lower values of $lambda_{R_e}$. While no environmental dependence is found for galaxies of lower mass. We discuss how our results can be understood as due to the different star formation and mass assembly histories of galaxies with varying mass.
rate research
Read More
Star formation rate density, $Sigma_{rm SFR}$, has shown a remarkable correlation with both components of the baryonic mass at kpc scales (i.e., the stellar mass density, and the molecular gas mass density; $Sigma_{ast}$, and $Sigma_{rm mol}$, respectively) for galaxies in the nearby Universe. In this study we propose an empirical relation between $Sigma_{rm SFR}$ and the baryonic mass surface density ($Sigma_{rm b}$ =$Sigma_{rm mol,Av}$ + $Sigma_{ast}$; where $Sigma_{rm mol,Av}$ is the molecular gas density derived from the optical extinction, Av) at kpc scales using the spatially-resolved properties of the MaNGA survey - the largest sample of galaxies observed via Integral Field Spectroscopy (IFS, $sim$ 8400 objects). We find that $Sigma_{rm SFR}$ tightly correlates with $Sigma_{rm b}$. Furthermore, we derive an empirical relation between the $Sigma_{rm SFR}$ and a second degree polynomial of $Sigma_{rm b}$ yielding a one-to-one relation between these two observables. Both, $Sigma_{rm b}$ and its polynomial form show a stronger correlation and smaller scatter with respect to $Sigma_{rm SFR}$ than the relations derived using the individual components of $Sigma_{rm b}$. Our results suggest that indeed these three parameters are physically correlated, suggesting a scenario in which the two components of the baryonic mass regulate the star-formation activity at kpc scales.
It remains an open question as to how long ago the morphology that we see in a present-day galaxy was typically imprinted. Studies of galaxy populations at different redshifts reveal that the balance of morphologies has changed over time, but such snapshots cannot uncover the typical timescales over which individual galaxies undergo morphological transformation, nor which are the progenitors of todays galaxies of different types. However, these studies also show a strong link between morphology and star-formation rate over a large range in redshift, which offers an alternative probe of morphological transformation. We therefore derive the evolution in star-formation rate and stellar mass of a sample of 4342 galaxies in the SDSS-IV MaNGA survey through a stellar population fossil record approach, and show that the average evolution of the population shows good agreement with known behaviour from previous studies. Although the correlation between a galaxys contemporaneous morphology and star-formation rate is strong over a large range of lookback times, we find that a galaxys present-day morphology only correlates with its relatively recent (~2 Gyr) star-formation history. We therefore find strong evidence that morphological transitions to galaxies current appearance occurred on timescales as short as a few billion years.
We present the integrated stellar mass-metallicity relation (MZR) for more than 1700 galaxies included in the integral field area SDSS-IV MaNGA survey. The spatially resolved data allow us to determine the metallicity at the same physical scale (effective radius in arcsecs, $mathrm{R_{eff}}$ ) using a heterogeneous set of ten abundance calibrators. Besides scale factors, the shape of the MZR is similar for all calibrators, consistent with those reported previously using single-fiber and integral field spectroscopy. We compare the residuals of this relation against the star formation rate (SFR) and specific SFR (sSFR). We do not find a strong secondary relation of the MZR with either SFR or the sSFR for any of the calibrators, in contrast with previous single-fiber spectroscopic studies. Our results agree with an scenario in which metal enrichment happens at local scales, with global outflows playing a secondary role in shaping the chemistry of galaxies and cold-gas inflows regulating the stellar formation.
Bars inhabit the majority of local-Universe disk galaxies and may be important drivers of galaxy evolution through the redistribution of gas and angular momentum within disks. We investigate the star formation and gas properties of bars in galaxies spanning a wide range of masses, environments, and star formation rates using the MaNGA galaxy survey. Using a robustly-defined sample of 684 barred galaxies, we find that fractional (or scaled) bar length correlates with the hosts offset from the star-formation main sequence. Considering the morphology of the H$alpha$ emission we separate barred galaxies into different categories, including barred, ringed, and central configurations, together with H$alpha$ detected at the ends of a bar. We find that only low-mass galaxies host star formation along their bars, and that this is located predominantly at the leading edge of the bar itself. Our results are supported by recent simulations of massive galaxies, which show that the position of star formation within a bar is regulated by a combination of shear forces, turbulence and gas flows. We conclude that the physical properties of a bar are mostly governed by the existing stellar mass of the host galaxy, but that they also play an important role in the galaxys ongoing star formation.
Gas stripping of spiral galaxies or mergers are thought to be the formation mechanisms of lenticular galaxies. In order to determine the conditions in which each scenario dominates, we derive stellar populations of both the bulge and disk regions of 279 lenticular galaxies in the MaNGA survey. We find a clear bimodality in stellar age and metallicity within the population of S0s and this is strongly correlated with stellar mass. Old and metal-rich bulges and disks belong to massive galaxies, and young and metal-poor bulges and disks are hosted by low-mass galaxies. From this we conclude that the bulges and disks are co-evolving. When the bulge and disk stellar ages are compared, we find that the bulge is almost always older than the disk for massive galaxies ($textrm{M}_{star} > 10^{10}~textrm{M}_{odot}$). The opposite is true for lower mass galaxies. We conclude that we see two separate populations of lenticular galaxies. The old, massive, and metal-rich population possess bulges that are predominantly older than their disks, which we speculate may have been caused by morphological or inside-out quenching. In contrast, the less massive and more metal-poor population have bulges with more recent star formation than their disks. We postulate they may be undergoing bulge rejuvenation (or disk fading), or compaction. Environment doesnt play a distinct role in the properties of either population. Our findings give weight to the notion that while the faded spiral scenario likely formed low-mass S0s, other processes, such as mergers, may be responsible for high-mass S0s.
Log in to be able to interact and post comments
comments
Fetching comments
Sign in to be able to follow your search criteria
