TY - JOUR
T1 - Mapping electron temperature variations across a spiral arm in ngc 1672
AU - Ho, I. Ting
AU - Kreckel, Kathryn
AU - Meidt, Sharon E.
AU - Groves, Brent
AU - Blanc, Guillermo A.
AU - Bigiel, Frank
AU - Dale, Daniel A.
AU - Emsellem, Eric
AU - Glover, Simon C.O.
AU - Grasha, Kathryn
AU - Kewley, Lisa J.
AU - Kruijssen, J. M.Diederik
AU - Lang, Philipp
AU - McElroy, Rebecca
AU - Kudritzki, Rolf Peter
AU - Sanchez-Blazquez, Patricia
AU - Sandstrom, Karin
AU - Santoro, Francesco
AU - Schinnerer, Eva
AU - Schruba, Andreas
N1 - Publisher Copyright:
© 2019. The American Astronomical Society. All rights reserved..
PY - 2019/11/10
Y1 - 2019/11/10
N2 - We report one of the first extragalactic observations of electron temperature variations across a spiral arm. Using Multi Unit Spectroscopic Explorer mosaic observations of the nearby galaxy NGC 1672, we measure the [N ii]λ5755 auroral line in a sample of 80 H ii regions in the eastern spiral arm of NGC 1672. We discover systematic temperature variations as a function of distance perpendicular to the spiral arm. The electron temperature is lowest on the spiral arm itself and highest on the downstream side. Photoionization models of different metallicity, pressure, and age of the ionizing source are explored to understand what properties of the interstellar medium drive the observed temperature variations. An azimuthally varying metallicity appears to be the most likely cause of the temperature variations. The electron temperature measurements solidify recent discoveries of azimuthal variations of oxygen abundance based on strong lines, and rule out the possibility that the abundance variations are artifacts of the strong-line calibrations.
AB - We report one of the first extragalactic observations of electron temperature variations across a spiral arm. Using Multi Unit Spectroscopic Explorer mosaic observations of the nearby galaxy NGC 1672, we measure the [N ii]λ5755 auroral line in a sample of 80 H ii regions in the eastern spiral arm of NGC 1672. We discover systematic temperature variations as a function of distance perpendicular to the spiral arm. The electron temperature is lowest on the spiral arm itself and highest on the downstream side. Photoionization models of different metallicity, pressure, and age of the ionizing source are explored to understand what properties of the interstellar medium drive the observed temperature variations. An azimuthally varying metallicity appears to be the most likely cause of the temperature variations. The electron temperature measurements solidify recent discoveries of azimuthal variations of oxygen abundance based on strong lines, and rule out the possibility that the abundance variations are artifacts of the strong-line calibrations.
UR - http://www.scopus.com/inward/record.url?scp=85075295324&partnerID=8YFLogxK
U2 - 10.3847/2041-8213/ab4feb
DO - 10.3847/2041-8213/ab4feb
M3 - Article
SN - 2041-8205
VL - 885
JO - Astrophysical Journal Letters
JF - Astrophysical Journal Letters
IS - 2
M1 - L31
ER -