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|Title:||SDSS-IV MaNGA: Modeling the spectral line-spread function to subpercent accuracy||Authors:||Law, David R.
Westfall, Kyle B.
Bershady, Matthew A.
BELFIORE, FRANCESCO MICHEL CONCETTO
Brownstein, Joel R.
|Issue Date:||2021||Journal:||THE ASTRONOMICAL JOURNAL||Number:||161||Issue:||2||First Page:||52||Abstract:||The Sloan Digital Sky Survey IV Mapping Nearby Galaxies at APO (MaNGA) program has been operating from 2014 to 2020, and has now observed a sample of 9269 galaxies in the low redshift universe (z ∼ 0.05) with integral-field spectroscopy. With rest-optical (λλ0.36-1.0 μm) spectral resolution R ∼ 2000 the instrumental spectral line-spread function (LSF) typically has 1σ width of about 70 km s−1, which poses a challenge for the study of the typically 20-30 km s−1 velocity dispersion of the ionized gas in present-day disk galaxies. In this contribution, we present a major revision of the MaNGA data pipeline architecture, focusing particularly on a variety of factors impacting the effective LSF (e.g., under-sampling, spectral rectification, and data cube construction). Through comparison with external assessments of the MaNGA data provided by substantially higher-resolution R ∼ 10,000 instruments, we demonstrate that the revised MPL-10 pipeline measures the instrumental LSF sufficiently accurately (≤0.6% systematic, 2% random around the wavelength of Hα) that it enables reliable measurements of astrophysical velocity dispersions σHα ∼ 20 km s−1 for spaxels with emission lines detected at signal-to-noise ratio > 50. Velocity dispersions derived from [O II], Hβ, [O III], [N II], and [S II] are consistent with those derived from Hα to within about 2% at σHα > 30 km s−1. Although the impact of these changes to the estimated LSF will be minimal at velocity dispersions greater than about 100 km s−1, scientific results from previous data releases that are based on dispersions far below the instrumental resolution should be reevaluated.||URI:||http://hdl.handle.net/20.500.12386/31301||URL:||https://iopscience.iop.org/article/10.3847/1538-3881/abcaa2
|Appears in Collections:||1.01 Articoli in rivista|
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