The present-day star formation rate of the Milky-Way determined from Spitzer detected young stellar objects

TL;DR

This paper introduces a novel galaxy-wide method to measure the Milky Way's star formation rate using young stellar objects detected by Spitzer, providing a more direct and potentially accurate estimate than traditional indirect tracers.

Contribution

The study presents the first galaxy-wide star formation rate measurement based on pre-main-sequence stars, utilizing population synthesis models and Spitzer data, improving accuracy over previous methods.

Findings

Star formation rate estimated between 0.68 and 1.45 Msun/yr.

Method reproduces observed YSO counts in the Galactic plane.

Results are consistent with prior estimates, with potential for refinement.

Abstract

We present initial results from a population synthesis model aimed at determining the star formation rate of the Milky-Way. We find that a total star formation rate of 0.68 to 1.45 Msun/yr is able to reproduce the observed number of young stellar objects in the Spitzer/IRAC GLIMPSE survey of the Galactic plane, assuming simple prescriptions for the 3D Galactic distributions of YSOs and interstellar dust, and using model SEDs to predict the brightness and color of the synthetic YSOs at different wavelengths. This is the first Galaxy-wide measurement derived from pre-main-sequence objects themselves, rather than global observables such as the total radio continuum, Halpha, or FIR flux. The value obtained is slightly lower than, but generally consistent with previously determined values. We will extend this method in the future to fit the brightness, color, and angular distribution of YSOs, and simultaneously make use of multiple surveys, to place constraints on the input assumptions, and reduce uncertainties in the star formation rate estimate. Ultimately, this will be one of the most accurate methods for determining the Galactic star formation rate, as it makes use of stars of all masses (limited only by sensitivity) rather than solely massive stars or indirect tracers of massive stars.