The volumetric star formation law in the Milky Way

Abstract

Several open questions on galaxy formation and evolution have their roots in the lack of a universal star formation law, that could univocally link the gas properties, e.g. its density, to the star formation rate (SFR) density. In a recent paper, we used a sample of nearby disc galaxies to infer the volumetric star formation (VSF) law, a tight correlation between the gas and the SFR volume densities derived under the assumption of hydrostatic equilibrium for the gas disc. However, due to the dearth of information about the vertical distribution of the SFR in these galaxies, we could not find a unique slope for the VSF law, but two alternative values. In this paper, we use the scale height of the SFR density distribution in our Galaxy adopting classical Cepheids (age$\lesssim 200$ Myr) as tracers of star formation. We show that this latter is fully compatible with the flaring scale height expected from gas in hydrostatic equilibrium. These scale heights allowed us to convert the observed surface densities of gas and SFR into the corresponding volume densities. Our results indicate that the VSF law ${\rho }_{\mathrm{SFR}}\propto {\rho }_{\mathrm{gas}}^{\alpha }$ with $\alpha \approx 2$ is valid in the Milky Way as well as in nearby disc galaxies.

9 pages, 4 figures, + 4 pages of Appendix, accepted by A&A

References in corpus (17)

• Theory of Star Formation
• The mass distribution and gravitational potential of the Milky Way
• The Role of Pressure in GMC Formation II: The H_2 - Pressure Relation
• What is Driving the HI Velocity Dispersion?
• The cold gaseous halo of NGC 891
• The Vertical Structure of the Outer Milky Way HI Disk
• HI holes and high-velocity clouds in the spiral galaxy NGC 6946
• The age-metallicity structure of the Milky Way disk
• Dark matter in the Milky Way, II. the HI gas distribution as a tracer of the gravitational potential
• The distribution of the ISM in the Milky Way A three-dimensional large-scale model
• Revisiting the Integrated Star Formation Law. Paper I: Non-Starbursting Galaxies
• An intuitive 3D map of the Galactic warp's precession traced by classical Cepheids
• Distribution and kinematics of atomic and molecular gas inside the Solar circle
• CO map and steep Kennicutt-Schmidt relation in the extended UV disk of M63
• Recognizing the fingerprints of the Galactic bar: a quantitative approach to comparing model (l,v) distributions to observation
• Extended Schmidt law holds for faint dwarf irregular galaxies
• Giant HI Hole inside the 3-kpc Ring and the North Polar Spur - The Galactic Crater -

Cited by in corpus (22)

• FIREbox: Simulating galaxies at high dynamic range in a cosmological volume
• Star formation scaling relations at ~100 pc from PHANGS: Impact of completeness and spatial scale
• Physical Processes in Star Formation
• The Star Formation Rate of the Milky Way as seen by Herschel
• Evidence for supernova feedback sustaining gas turbulence in nearby star-forming galaxies
• The impact of gas disc flaring on rotation curve decomposition and revisiting baryonic and dark-matter relations for nearby galaxies
• The volumetric star formation law for nearby galaxies -- Extension to dwarf galaxies and low-density regions
• Calibration of hybrid resolved star formation rate recipes based on PHANGS-MUSE H$\alpha$ and H$\beta$ maps
• The resolved scaling relations in DustPedia: Zooming in on the local Universe
• A geostatistical analysis of multiscale metallicity variations in galaxies [I]: Introduction and comparison of high-resolution metallicity maps to an analytic metal transport model
• Hydrodynamic simulations of an isolated star-forming gas cloud in the Virgo cluster
• 3D modeling of the molecular gas kinematics in optically-selected jellyfish galaxies
• The Kennicutt-Schmidt law and the main sequence of galaxies in Newtonian and Milgromian dynamics
• Star cluster formation and feedback in different environments of a Milky Way-like galaxy
• The effect of diffuse background on the spatially-resolved Schmidt relation in nearby spiral galaxies
• Theoretical modelling of two-component molecular discs in spiral galaxies
• Local gravitational instability of stratified rotating fluids: 3D criteria for gaseous discs
• LEGA-C: analysis of dynamical masses from ionized gas and stellar kinematics at z~0.8
• The Volumetric Extended-Schmidt Law: A Unity Slope
• A path towards constraining the evolution of the interstellar medium and outflows in the Milky Way using APOGEE
• On the formation of spiral arms in dwarf galaxies
• On volume density and star formation in nearby molecular clouds