TY - JOUR
T1 - The VIRUS-P Exploration of Nearby Galaxies (VENGA)
T2 - Spatially resolved gas-phase metallicity distributions in barred and unbarred spirals
AU - Kaplan, Kyle F.
AU - Jogee, Shardha
AU - Kewley, Lisa
AU - Blanc, Guillermo A.
AU - Weinzirl, Tim
AU - Song, Mimi
AU - Drory, Niv
AU - Luo, Rongxin
AU - van den Bosch, Remco C.E.
N1 - Publisher Copyright:
© 2016 The Authors.
PY - 2016/10/21
Y1 - 2016/10/21
N2 - We present a study of the excitation conditions and metallicity of ionized gas (Zgas) in eight nearby barred and unbarred spiral galaxies from the VIRUS-P Exploration of Nearby Galaxies (VENGA) survey, which provides high spatial sampling and resolution (median ~387 pc), large coverage from the bulge to outer disc, broad wavelength range (3600-6800 Å), and medium spectral resolution (~120 km s-1 at 5000 Å). Our results are: (1) We present high resolution gas excitation maps to differentiate between regions with excitation typical of Seyfert, LINER, or recent star formation. We find LINER-type excitation at large distances (3-10 kpc) from the centre, and associate this excitation with diffuse ionized gas (DIG). (2) After excluding spaxels dominated by Seyfert, LINER, or DIG, we produce maps with the best spatial resolution and sampling to date of the ionization parameter q, star formation rate, and Zgas using common strong line diagnostics. We find that isolated barred and unbarred spirals exhibit similarly shallow Zgas profiles from the inner kpc out to large radii (7-10 kpc or 0.5-1.0 R25). This implies that if profiles had steeper gradients at earlier epochs, then the presentday bar is not the primary driver flattening gradients over time. This result contradicts earlier claims, but agrees with recent IFU studies. (3) The Zgas gradients in our z ~ 0 massive spirals are markedly shallower, by ~0.2 dex kpc-1, than published gradients for lensed lower mass galaxies at z ~ 1.5-2.0. Cosmologically motivated hydrodynamical simulations best match this inferred evolution, but the match is sensitive to adopted stellar feedback prescriptions.
AB - We present a study of the excitation conditions and metallicity of ionized gas (Zgas) in eight nearby barred and unbarred spiral galaxies from the VIRUS-P Exploration of Nearby Galaxies (VENGA) survey, which provides high spatial sampling and resolution (median ~387 pc), large coverage from the bulge to outer disc, broad wavelength range (3600-6800 Å), and medium spectral resolution (~120 km s-1 at 5000 Å). Our results are: (1) We present high resolution gas excitation maps to differentiate between regions with excitation typical of Seyfert, LINER, or recent star formation. We find LINER-type excitation at large distances (3-10 kpc) from the centre, and associate this excitation with diffuse ionized gas (DIG). (2) After excluding spaxels dominated by Seyfert, LINER, or DIG, we produce maps with the best spatial resolution and sampling to date of the ionization parameter q, star formation rate, and Zgas using common strong line diagnostics. We find that isolated barred and unbarred spirals exhibit similarly shallow Zgas profiles from the inner kpc out to large radii (7-10 kpc or 0.5-1.0 R25). This implies that if profiles had steeper gradients at earlier epochs, then the presentday bar is not the primary driver flattening gradients over time. This result contradicts earlier claims, but agrees with recent IFU studies. (3) The Zgas gradients in our z ~ 0 massive spirals are markedly shallower, by ~0.2 dex kpc-1, than published gradients for lensed lower mass galaxies at z ~ 1.5-2.0. Cosmologically motivated hydrodynamical simulations best match this inferred evolution, but the match is sensitive to adopted stellar feedback prescriptions.
KW - Galaxies: ISM
KW - Galaxies: abundances
KW - Galaxies: spiral
UR - http://www.scopus.com/inward/record.url?scp=84988807180&partnerID=8YFLogxK
U2 - 10.1093/mnras/stw1422
DO - 10.1093/mnras/stw1422
M3 - Article
SN - 0035-8711
VL - 462
SP - 1642
EP - 1682
JO - Monthly Notices of the Royal Astronomical Society
JF - Monthly Notices of the Royal Astronomical Society
IS - 2
ER -