We study the global star-formation rate (SFR) vs. stellar mass (M * ) correlation, and the spatially-resolved SFR surface density (Σ S FR ) vs. stellar mass surface density (Σ * ) correlation, in a sample of ∼ 2, 000 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 × 10 7 M ⊙ 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 SFMS's, by ∼ −1.5 dex on average. We explore how the global/local SFMS's 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.

We present spatially resolved stellar population (SP) age maps, average radial profiles and gradients for the first 62 active galactic nuclei (AGN) observed with Sloan Digital Sky Survey (SDSS)-IV Mapping Nearby Galaxies at Apache Point Observatory (MaNGA) to study the effects of the active nuclei on the star formation history of the host galaxies. These results, derived using the STARLIGHT code, are compared with a control sample of non-active galaxies matching the properties of the AGN hosts. We find that the fraction of young SPs in highluminosity AGN is higher in the inner (R ≤ 0.5 R e) regions when compared with the control sample; low-luminosity AGN, on the other hand, present very similar fractions of young stars to the control sample hosts for the entire studied range (1 R e). The fraction of intermediate-age SP of the AGN hosts increases outwards, with a clear enhancement when compared with the control sample. The inner region of the galaxies (AGN and control galaxies) presents a dominant old SP, whose fraction decreases outwards. We also compare our results (differences between AGN and control galaxies) for the early-and late-type hosts and find no significant differences. In summary, our results suggest that the most luminous AGN seems to have been triggered by a recent supply of gas that has also triggered recent star formation (t ≤ 40 Myr) in the central region.

We present the second data release for the HI-MaNGA programme of H i follow-up observations for the SDSS-IV MaNGA survey. This release contains measurements for 3669 unique galaxies, combining 2108 Green Bank Telescope observations with an updated crossmatch of the MaNGA sample with the ALFALFA survey. We combine these data with MaNGA spectroscopic measurements to examine relationships between H i-to-stellar mass ratio (${\rm M_{H\, {\small I}}/{M_*}}$) and average ISM/star formation properties probed by optical emission lines. ${\rm M_{H\, {\small I}}/{M_*}}$ is very weakly correlated with the equivalent width of Hα, implying a loose connection between the instantaneous star formation rate and the HI reservoir, although the link between ${\rm M_{H\, {\small I}}/{M_*}}$ and star formation strengthens when averaged even over only moderate timescales (∼30 Myrs). Galaxies with elevated H i depletion times have enhanced [O i]/Hα and depressed Hα surface brightness, consistent with more H i residing in a diffuse and/or shock heated phase which is less capable of condensing into molecular clouds. Of all optical lines, ${\rm M_{H\, {\small I}}/{M_*}}$ correlates most strongly with oxygen equivalent width, EW(O), which is likely a result of the existing correlation between ${\rm M_{H\, {\small I}}/{M_*}}$ and gas-phase metallicity. Residuals in the ${\rm M_{H\, {\small I}}/{M_*}}$−EW(O) relation are again correlated with [O i]/Hα and Hα surface brightness, suggesting they are also driven by variations in the fraction of diffuse and/or shock-heated gas. We recover the strong anti-correlation between ${\rm M_{H\, {\small I}}/{M_*}}$ and gas-phase metallicity seen in previous studies. We also find a relationship between ${\rm M_{H\, {\small I}}/{M_*}}$ and [O i]6302/Hα, suggesting that higher fractions of diffuse and/or shock-heated gas are more prevalent in gas-rich galaxies.

Context. We study the spatially resolved properties of 343 elliptical galaxies with the Mapping Nearby Galaxies at the Apache Point Observatory (MaNGA) survey. Aims. Our goal is to understand the fundamental processes of formation and quenching of elliptical galaxies. Methods. We used the DESI Legacy Imaging Surveys for accurate morphological classification. Based on integrated spectroscopic properties and colors, we classified seven classes of elliptical galaxies. We inferred the stellar age and metallicity gradients out to a 1.5 effective radius (Reff) of classical “red and dead”, recently quenched, and blue star-forming ellipticals (CLEs, RQEs, and BSFs), corresponding to 73%, 10%, and 4% of the sample, respectively. Additionally, we reconstructed their global and radial histories of star formation and mass growth. Results. The mass- and luminosity-weighted age gradients of CLEs are nearly flat or mildly negative, with small differences between both ages. The respective metallicity gradients are negative (∇log[Zmw] = −0.11−0.08+0.07 dex/Reff and ∇log[Zlw] = −0.11−0.07+0.06 dex/Reff, respectively), being flatter as the mass is smaller. The more massive CLEs formed stars earlier and quenched faster than the less massive ones. The CLEs show a weak inside-out growth and a clear inside-out quenching. They finished their quenching globally 3.8  ±  1.2 Gyr ago on average, with quenching time-scales of 3.4  ±  0.8 Gyr. At M⋆ < 1011 M⊙, the age and Z gradients of the RQEs and BSFs are flatter than those of the CLEs, but with larger scatters. They show very weak inside-out growth and quenching, which is slow and not even completed at z ∼ 0 for the BSFs. Instead, the massive RQEs show an outside-in quenching and positive gradients in the luminosity-weighted age and stellar metallicities. The RQEs of all masses quenched 1.2 ± 0.9 Gyr ago on average. Conclusions. Our results for the CLEs are consistent with a two-phase scenario where their inner parts formed by an early and coeval dissipative collapse with a consequent burst of star formation and further quenching, whereas the outer parts continued their assembly, likely by dry mergers. We also discuss some evolutionary scenarios for the RQE and BSF galaxies that would agree with the generic results.

Abstract We present the H i-MaNGA programme of H i follow-up for the Mapping Nearby Galaxies at Apache Point Observatory (MaNGA) survey. MaNGA, which is part of the Fourth phase of the Sloan Digital Sky Surveys, is in the process of obtaining integral field unit spectroscopy for a sample of ∼10 000 nearby galaxies. We give an overview of the H i 21cm radio follow-up observing plans and progress and present data for the first 331 galaxies observed in the 2016 observing season at the Robert C. Bryd Green Bank Telescope. We also provide a cross-match of the current MaNGA (DR15) sample with publicly available H i data from the Arecibo Legacy Fast Arecibo L-band Feed Array survey. The addition of H i data to the MaNGA data set will strengthen the survey’s ability to address several of its key science goals that relate to the gas content of galaxies, while also increasing the legacy of this survey for all extragalactic science.