TY - JOUR
T1 - SDSS-IV MaNGA
T2 - calibration of astrophysical line-widths in the Hα region using HexPak observations
AU - Chattopadhyay, Sabyasachi
AU - Bershady, Matthew A.
AU - Law, David R.
AU - Westfall, Kyle
AU - Shetty, Shravan
AU - Machuca, Camilo
AU - Cappellari, Michele
AU - Rubin, Kate H. R.
AU - Bundy, Kevin
AU - Penny, Samantha
PY - 2024/3/1
Y1 - 2024/3/1
N2 - We have re-observed ∼40 low-inclination, star-forming galaxies from the MaNGA survey (σ ∼ 65 km s−1) at ∼6.5 times higher spectral resolution (σ ∼ 10 km s−1) using the HexPak integral field unit on the WIYN 3.5-m telescope. The aim of these observations is to calibrate MaNGA's instrumental resolution and to characterize turbulence in the warm interstellar medium and ionized galactic outflows. Here we report the results for the Hα region observations as they pertain to the calibration of MaNGA's spectral resolution. Remarkably, we find that the previously reported MaNGA line-spread-function (LSF) Gaussian width is systematically underestimated by only 1 per cent. The LSF increase modestly reduces the characteristic dispersion of H II regions-dominated spectra sampled at 1-2 kpc spatial scales from 23 to 20 km s−1 in our sample, or a 25 per cent decrease in the random-motion kinetic energy. This commensurately lowers the dispersion zeropoint in the relation between line-width and star-formation rate surface-density in galaxies sampled on the same spatial scale. This modest zero-point shift does not appear to alter the power-law slope in the relation between line-width and star-formation rate surface-density. We also show that adopting a scheme whereby corrected line-widths are computed as the square root of the median of the difference in the squared measured line width and the squared LSF Gaussian avoids biases and allows for lower signal-to-noise data to be used reliably.
AB - We have re-observed ∼40 low-inclination, star-forming galaxies from the MaNGA survey (σ ∼ 65 km s−1) at ∼6.5 times higher spectral resolution (σ ∼ 10 km s−1) using the HexPak integral field unit on the WIYN 3.5-m telescope. The aim of these observations is to calibrate MaNGA's instrumental resolution and to characterize turbulence in the warm interstellar medium and ionized galactic outflows. Here we report the results for the Hα region observations as they pertain to the calibration of MaNGA's spectral resolution. Remarkably, we find that the previously reported MaNGA line-spread-function (LSF) Gaussian width is systematically underestimated by only 1 per cent. The LSF increase modestly reduces the characteristic dispersion of H II regions-dominated spectra sampled at 1-2 kpc spatial scales from 23 to 20 km s−1 in our sample, or a 25 per cent decrease in the random-motion kinetic energy. This commensurately lowers the dispersion zeropoint in the relation between line-width and star-formation rate surface-density in galaxies sampled on the same spatial scale. This modest zero-point shift does not appear to alter the power-law slope in the relation between line-width and star-formation rate surface-density. We also show that adopting a scheme whereby corrected line-widths are computed as the square root of the median of the difference in the squared measured line width and the squared LSF Gaussian avoids biases and allows for lower signal-to-noise data to be used reliably.
KW - galaxies: ISM
KW - galaxies: kinematics & dynamics
KW - techniques: imaging spectroscopy
UR - http://www.scopus.com/inward/record.url?scp=85185402267&partnerID=8YFLogxK
U2 - 10.1093/mnras/stae371
DO - 10.1093/mnras/stae371
M3 - Article
AN - SCOPUS:85185402267
SN - 0035-8711
VL - 528
SP - 5377
EP - 5393
JO - Monthly Notices of the Royal Astronomical Society
JF - Monthly Notices of the Royal Astronomical Society
IS - 3
ER -