Understanding the star formation rate (SFR) history of the Milky Way is crucial for comprehending galactic evolution.
Previous studies have provided varying insights into the SFR history, highlighting the need for more robust data and analysis.
Purpose of the Study:
To derive the star formation rate history of the Milky Way using chromospheric age distribution.
To investigate fluctuations and secular trends in the Milky Way's star formation over cosmic timescales.
Main Methods:
Analyzed the chromospheric age distribution of 552 stars in the solar neighborhood.
Incorporated metallicity dependence of chromospheric emission, and applied corrections for incompleteness, scale height-age correlations, and stellar evolutionary effects.
Main Results:
Identified significant fluctuations in the global star formation rate (SFR) with amplitudes of 2-3 on timescales of 0.2-1 Gyr.
Found evidence for a slow secular increase in SFR, suggesting a record of galactic accumulation.
Strongly ruled out a smooth, constant SFR history, confirming previous findings.
Conclusions:
The Milky Way's star formation history is not constant but exhibits significant fluctuations.
Galactic SFR can vary coherently on large scales, providing insights into galaxy-wide processes.
The findings challenge models assuming a steady star formation rate and emphasize the dynamic nature of galaxy evolution.