SDSS-IV MaNGA: Modeling the Spectral Line Spread Function to Sub-Percent Accuracy. (arXiv:2011.04675v2 [astro-ph.IM] UPDATED)

SDSS-IV MaNGA: Modeling the Spectral Line Spread Function to Sub-Percent Accuracy. (arXiv:2011.04675v2 [astro-ph.IM] UPDATED)
<a href="http://arxiv.org/find/astro-ph/1/au:+Law_D/0/1/0/all/0/1">David R. Law</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Westfall_K/0/1/0/all/0/1">Kyle B. Westfall</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Bershady_M/0/1/0/all/0/1">Matthew A. Bershady</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Cappellari_M/0/1/0/all/0/1">Michele Cappellari</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Yan_R/0/1/0/all/0/1">Renbin Yan</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Belfiore_F/0/1/0/all/0/1">Francesco Belfiore</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Bizyaev_D/0/1/0/all/0/1">Dmitry Bizyaev</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Brownstein_J/0/1/0/all/0/1">Joel R. Brownstein</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Chen_Y/0/1/0/all/0/1">Yanping Chen</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Cherinka_B/0/1/0/all/0/1">Brian Cherinka</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Drory_N/0/1/0/all/0/1">Niv Drory</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Lazarz_D/0/1/0/all/0/1">Daniel Lazarz</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Shetty_S/0/1/0/all/0/1">Shravan Shetty</a>

The SDSS-IV Mapping Nearby Galaxies at APO (MaNGA) program has been operating
from 2014-2020, and has now observed a sample of 9,269 galaxies in the low
redshift universe (z ~ 0.05) with integral-field spectroscopy. With
rest-optical (lambdalambda 0.36 – 1.0 um) spectral resolution R ~ 2000 the
instrumental spectral line-spread function (LSF) typically has 1sigma width of
about 70 km/s, which poses a challenge for the study of the typically 20-30
km/s 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., undersampling, 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 line
spread function sufficiently accurately (<= 0.6% systematic, 2% random around
the wavelength of Halpha) that it enables reliable measurements of
astrophysical velocity dispersions sigma_Halpha ~ 20 km/s for spaxels with
emission lines detected at SNR > 50. Velocity dispersions derived from [O II],
Hbeta, [O III], [N II], and [S II] are consistent with those derived from
Halpha to within about 2% at sigma_Halpha > 30 km/s. Although the impact of
these changes to the estimated LSF will be minimal at velocity dispersions
greater than about 100 km/s, scientific results from previous data releases
that are based on dispersions far below the instrumental resolution should be
reevaulated.

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