H i-MaNGA: tracing the physics of the neutral and ionized ISM with the second data release

Abstract

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.

Measuring the HI content of individual galaxies out to the epoch of reionization with [CII]

“…In addition to examining the evolution of the H i gas fraction with redshift, here we quantify whether the high-redshift measurements follow the observed anticorrelation with gas-phase metallicity observed in the local Universe (Hughes et al 2013;Brown et al 2018;Stark et al 2021). At fixed redshifts, this is equivalently represented as a decrease in the H i fraction with increasing stellar mass (Catinella et al 2013;Brown et al 2015).…”

“…In Figure 5 we show the gas fraction M HI /M as a function of metal abundance 12 + log(O/H) for each galaxy in our compiled high-z sample. For comparison, we overplot the xGASS catalog of galaxies at z ∼ 0 with direct H i 21-cm observations (Catinella et al 2018), together with the empirical relation derived for the H i-MaNGA sample galaxies (Stark et al 2021). The combined sample of galaxies, spanning redshifts from z = 0 − 6, is observed to closely follow this local, empirical relation.…”

“…Metal abundances are determined for each high-redshift galaxy based on the FMR(Curti et al 2020). The xGASS catalog of galaxies at z ∼ 0 with direct H i 21-cm observations(Catinella et al 2018) is shown the grey-shaded contours for comparison, together with the empirical relation derived for the H i-MaNGA sample galaxies(Stark et al 2021) (black dashed line). Both nearby and distant galaxies, at z = 0 − 6, are observed to follow this fundamental relation.…”

SDSS-IV MaNGA: Understanding Ionized Gas Turbulence using Integral Field Spectroscopy of 4500 Star-Forming Disk Galaxies

“…Additionally, we compute the HI gas fraction using Green Bank Telescope and ALFALFA HI masses drawn from the ongoing HI-MaNGA survey (Masters et al 2019;Stark et al 2021). 19 We find that 1732 of our galaxies have HI measurements flagged as reliable in v2.0.1 of the HI-MaNGA catalog.…”

“…Intensity-weighted mean Hα velocity dispersion for galaxies in the MaNGA sample as a function of their specific star formation rate (left-hand panel), SFR offset from the main sequence (middle panel), and HI gas fraction (right-hand panel). HI gas fractions are based on 1732 galaxies of the sample with HI gas masses drawn from Stark et al (2021). The majority of the trends in all panels are best explained by the vertical offset between individual quartiles of the galaxy sample in total SFR (colored lines and points).…”