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ABSTRACT The depletion of elements onto dust grains is characterized using a generalized depletion strength F* for any sightline, and trend-line parameters AX, BX, and zX. The parameters AX, BX, and zX define the relative depletion pattern, for which values are published in previous works. The present study uses these parameters to calculate post-depleted gas-phase abundances of 15 different elements while varying F* from 0 to 1. An analysis of emergent strong spectral line intensities, obtained by inputting the calculated abundances into a cloudy model, shows that the depletion strength has a non-trivial effect on predicted emission lines and the thermal balance of the ionized cloud. The amount by which elements deplete also affects the coolant abundances in the gas. Furthermore, it was found that each of the parameters – metallicity, ionization parameter U, and depletion strength F* have degenerate effects on the emission-line strengths, and thermal balance of the interstellar medium (ISM). Finally, comparing our results to a sample of H ii regions using data obtained from the Mapping Nearby Galaxies at Apache Point Observatory survey (MaNGA) revealed that the best-fit F* was approximately 0.5. However, this best-fitting value does not work well for all metallicities. Removing the sulfur depletion and changing the nitrogen abundance pattern can improve the fit. As a result, extra observational evidence is required to verify the choices of parameters and better constrain the typical depletion strength in galaxies. 

ABSTRACT Atomic species in the interstellar medium transition out of their gas phase mainly by depletion on to dust. In this study, we examine if there is any change to the spectral-line ratio predictions from a photoionization model of the Orion H ii region when the degree of dust depletions is altered according to the most recently published model. We use equations and parameters published by previous works, in order to streamline the calculation of depleted abundances within cloudy. Our aim is for cloudy users to be able to vary the level of depletion using a single parameter in the input file. This makes it possible to explore predictions for a large range of depletions more efficiently. Finally, we discuss the results obtained for a model of the Orion Nebula when the degree of depletions are manipulated in this way. We found that the intensity of line ratios are significantly affected by depletions on to dust grains. Further, we found that adjusting dust abundances along with depletion affects the structure and the overall temperature of the H+ layer across the H ii region. 

We use the statistical power of the MaNGA integral-field spectroscopic galaxy survey to improve the definition of strong line diagnostic boundaries used to classify gas ionization properties in galaxies. We detect line emission from 3.6 million spaxels distributed across 7400 individual galaxies spanning a wide range of stellar masses, star formation rates, and morphological types, and find that the gas-phase velocity dispersion σHα correlates strongly with traditional optical emission-line ratios such as [S II]/Hα, [N II]/Hα, [O I]/Hα, and [O III]/Hβ. Spaxels whose line ratios are most consistent with ionization by galactic H II regions exhibit a narrow range of dynamically cold line-of-sight velocity distributions (LOSVDs) peaked around 25 km s-1 corresponding to a galactic thin disk, while those consistent with ionization by active galactic nuclei (AGNs) and low-ionization emission-line regions (LI(N)ERs) have significantly broader LOSVDs extending to 200 km s-1. Star-forming, AGN, and LI(N)ER regions are additionally well separated from each other in terms of their stellar velocity dispersion, stellar population age, Hα equivalent width, and typical radius within a given galaxy. We use our observations to revise the traditional emission-line diagnostic classifications so that they reliably identify distinct dynamical samples both in two-dimensional representations of the diagnostic line ratio space and in a multidimensional space that accounts for the complex folding of the star-forming model surface. By comparing the MaNGA observations to the SDSS single-fiber galaxy sample, we note that the latter is systematically biased against young, low-metallicity star-forming regions that lie outside of the 3″ fiber footprint. 

Abstract This paper documents the seventeenth data release (DR17) from the Sloan Digital Sky Surveys; the fifth and final release from the fourth phase (SDSS-IV). DR17 contains the complete release of the Mapping Nearby Galaxies at Apache Point Observatory (MaNGA) survey, which reached its goal of surveying over 10,000 nearby galaxies. The complete release of the MaNGA Stellar Library accompanies this data, providing observations of almost 30,000 stars through the MaNGA instrument during bright time. DR17 also contains the complete release of the Apache Point Observatory Galactic Evolution Experiment 2 survey that publicly releases infrared spectra of over 650,000 stars. The main sample from the Extended Baryon Oscillation Spectroscopic Survey (eBOSS), as well as the subsurvey Time Domain Spectroscopic Survey data were fully released in DR16. New single-fiber optical spectroscopy released in DR17 is from the SPectroscipic IDentification of ERosita Survey subsurvey and the eBOSS-RM program. Along with the primary data sets, DR17 includes 25 new or updated value-added catalogs. This paper concludes the release of SDSS-IV survey data. SDSS continues into its fifth phase with observations already underway for the Milky Way Mapper, Local Volume Mapper, and Black Hole Mapper surveys.