Document Type
Article
Publication Date
11-11-2016
Abstract
We introduce SPARC (Spitzer Photometry and Accurate Rotation Curves): a sample of 175 nearby galaxies with new surface photometry at 3.6 μm and high-quality rotation curves from previous H I/Hα studies. SPARC spans a broad range of morphologies (S0 to Irr), luminosities (∼5 dex), and surface brightnesses (∼4 dex). We derive [3.6] surface photometry and study structural relations of stellar and gas disks. We find that both the stellar mass-H I mass relation and the stellar radius-H i radius relation have significant intrinsic scatter, while the H I mass-radius relation is extremely tight. We build detailed mass models and quantify the ratio of baryonic to observed velocity (Vbar/Vobs) for different characteristic radii and values of the stellar mass-to-light ratio (ϒ∗) at [3.6]. Assuming ϒ∗ ≃ 0.5 M⊙/L⊙ (as suggested by stellar population models), we find that (i) the gas fraction linearly correlates with total luminosity; (ii) the transition from star-dominated to gas-dominated galaxies roughly corresponds to the transition from spiral galaxies to dwarf irregulars, in line with density wave theory; and (iii) Vbar/Vobs varies with luminosity and surface brightness: high-mass, high-surface-brightness galaxies are nearly maximal, while low-mass, low-surface-brightness galaxies are submaximal. These basic properties are lost for low values of ϒ∗ ≃ 0.2 M⊙/L⊙ as suggested by the DiskMass survey. The mean maximum-disk limit in bright galaxies is ϒ∗ ≃ 0.7 M⊙/L⊙ at [3.6]. The SPARC data are publicly available and represent an ideal test bed for models of galaxy formation.
Keywords
dark matter, galaxies: dwarf, galaxies: irregular, galaxies: kinematics and dynamics, galaxies: spiral, galaxies: structure
Publication Title
Astronomical Journal
Rights
© The American Astronomical Society. All rights reserved. This content is free to access, download, and share. For all other uses, you must obtain permission to reuse content: https://journals.aas.org/article-charges-and-copyright/#AAS_material
Recommended Citation
SPARC: Mass Models for 175 Disk Galaxies with Spitzer Photometry and Accurate Rotation Curves. Federico Lelli et al 2016 AJ 152 157
Manuscript Version
Final Publisher Version