ﻻ يوجد ملخص باللغة العربية
The tight correlation between total galaxy stellar mass and star formation rate (SFR) has become known as the star forming main sequence. Using ~487,000 spaxels from galaxies observed as part of the Sloan Digital Sky Survey Mapping Galaxies at Apache Point Observatory (MaNGA) survey, we confirm previous results that a correlation also exists between the surface densities of star formation (Sigma_SFR) and stellar mass (Sigma_mass) on kpc scales, representing a `resolved main sequence. Using a new metric (Delta Sigma_SFR), which measures the relative enhancement or deficit of star formation on a spaxel-by-spaxel basis relative to the resolved main sequence, we investigate the SFR profiles of 864 galaxies as a function of their position relative to the global star forming main sequence (Delta SFR). For galaxies above the global main sequence (positive Delta SFR) Delta Sigma_SFR is elevated throughout the galaxy, but the greatest enhancement in star formation occurs at small radii (< 3 kpc, or 0.5 R_e). Moreover, galaxies that are at least a factor of three above the main sequence show diluted gas phase metallicities out to 2 R_e, indicative of metal-poor gas inflows accompanying the starbursts. For quiescent/passive galaxies that lie at least a factor of 10 below the star forming main sequence there is an analogous deficit of star formation throughout the galaxy with the lowest values of Delta Sigma_SFR in the central 3 kpc. Our results are in qualitative agreement with the `compaction scenario in which a central starburst leads to mass growth in the bulge and may ultimately precede galactic quenching from the inside-out.
The bimodality in observed present-day galaxy colours has long been a challenge for hierarchical galaxy formation models, as it requires some physical process to quench (and keep quenched) star formation in massive galaxies. Here we examine phenomeno
Using spatially resolved spectroscopy from SDSS-IV MaNGA we have demonstrated that low ionisation emission line regions (LIERs) in local galaxies result from photoionisation by hot evolved stars, not active galactic nuclei. LIERs are ubiquitous in bo
Radial age gradients hold the cumulative record of the multitude of physical processes driving the build-up of stellar populations and the ensuing star formation (SF) quenching process in galaxy bulges, therefore potentially sensitive discriminators
We derive two-dimensional dust attenuation maps at $sim1~mathrm{kpc}$ resolution from the UV continuum for ten galaxies on the $zsim2$ Star-Forming Main Sequence (SFMS). Comparison with IR data shows that 9 out of 10 galaxies do not require further o
We compare the radial profiles of the specific star formation rate (sSFR) in a sample of 169 star-forming galaxies in close pairs with those of mass-matched control galaxies in the SDSS-IV MaNGA survey. We find that the sSFR is centrally enhanced (wi