BGM FASt: Besançon Galaxy Model for Big Data. Simultaneous inference of the IMF, SFH and density in the Solar Neighbourhood

Abstract

We develop a new theoretical framework to generate Besançon Galaxy Model fast approximate simulations (BGM FASt) to address fundamental questions of the Galactic structure and evolution performing multi-parameter inference. As a first application of our strategy we simultaneously infer the IMF, the star formation history and the stellar mass density in the Solar Neighbourhood. The BGM FASt strategy is based on a reweighing scheme, that uses a specific pre-sampled simulation, and on the assumption that the distribution function of the generated stars in the Galaxy can be described by an analytical expression. To validate BGM FASt we execute a set of tests. Finally, we use BGM FASt with an approximate Bayesian computation algorithm to obtain the posterior PDF of the inferred parameters, by comparing synthetic versus Tycho-2 colour-magnitude diagrams. Results: The validation shows a very good agreement between BGM FASt and the standard BGM, with BGM FASt being $\approx 10^4$ times faster. By analysing Tycho-2 data we obtain a thin disc star formation history decreasing in time and a present rate of $1.2\pm 0.2M_{\odot }/yr$. The resulting total stellar mass density in the Solar Neighbourhood is $0.051_{-0.005}^{+0.002}{M}_{\odot }/p{c}^3$ and the local dark matter density is $0.012\pm 0.001M_{\odot }/p{c}^3$. For the composite IMF we obtain a slope of ${\alpha }_2={2.1}_{-0.3}^{+0.1}$ in the mass range between $0.5M_{\odot }$ and $1.53M_{\odot }$. The results of the slope at the high mass range are trustable up to $4M_{\odot }$ and highly depend on the choice of the extinction map (obtaining ${\alpha }_3={2.9}_{-0.2}^{+0.2}$ and ${\alpha }_3={3.7}_{-0.2}^{+0.2}$ respectively, for two different extinction maps). Systematic uncertainties are not included. Conclusions: The good performance of BGM FASt demonstrates that it is a very valuable tool to perform multi-parameter inference using Gaia data releases.

arXiv commentAccepted for publication by A&A. 30 pages (23 pages of main body and 7 pages of Appendixes) , 15 figures and 4 tables

References in corpus (27)

• Gaia Data Release 2. Summary of the contents and survey properties
• The Milky Way Tomography with SDSS: I. Stellar Number Density Distribution
• Mass models of the Milky Way
• Modelling the Galactic Interstellar Extinction Distribution in Three Dimensions
• Adaptive approximate Bayesian computation
• Galactic-Field IMFs of Massive Stars
• Improved Estimates of the Milky Way's Stellar Mass and Star Formation Rate from Hierarchical Bayesian Meta-Analysis
• Three Dimensional Structure of the Milky Way Disk
• Scaled solar tracks and isochrones in a large region of the Z-Y plane I. From the ZAMS to the TP-AGB end for 0.15 - 2.5 Mo stars
• The dark matter density at the Sun's location
• On the mass-to-light ratio of the local Galactic disc and the optical luminosity of the Galaxy
• Kinematics and history of the solar neighbourhood revisited
• Stars, Gas, and Dark Matter in the Solar Neighborhood
• Reconstructing the star formation history of the Milky Way disc(s) from chemical abundances
• The impact of the metallicity and star formation rate on the time-dependent galaxy-wide stellar initial mass function
• Stellar Inventory of the Solar Neighborhood using Gaia DR1
• A highly abnormal massive star mass function in the Orion Nebula cluster and the dynamical decay of trapezia systems
• Likelihood-free Markov chain Monte Carlo
• A parametric description of the 3D structure of the Galactic Bar/Bulge using the VVV survey
• Kinematics of the local disk from the RAVE survey and the Gaia first data release
• Local Surface Density of the Galactic Disk from a 3-D Stellar Velocity Sample
• The Effect of Star Formation History on the Inferred Initial Stellar Mass Function
• Quasi integral of motion for axisymmetric potentials
• Towards a fully consistent Milky Way disc model - III. Constraining the initial mass function
• Besançon Galactic model analysis of MOA-II microlensing: evidence for a mass deficit in the inner bulge
• Spiral arm kinematics for Milky Way stellar populations
• Theory of Stellar Population Synthesis with an application to N-Body simulations

Cited by in corpus (7)

• Gaia Early Data Release 3: The Gaia Catalogue of Nearby Stars
• The impact of the metallicity and star formation rate on the time-dependent galaxy-wide stellar initial mass function
• The Canada-France Imaging Survey: Reconstructing the Milky Way Star Formation History from its White Dwarf Population
• The stellar Initial Mass Function of the solar neighbourhood revealed by Gaia
• Analysis of galaxy kinematics based on Cepheids from the Gaia DR2 Catalogue
• Towards a fully consistent Milky Way disk model -- IV. The impact of Gaia DR2 and APOGEE
• Gaia Early Data Release 3: Structure and properties of the Magellanic Clouds