The Magellanic Squall: Gas Replenishment from the Small to Large Magellanic Cloud

TL;DR

This study shows that tidal interactions between the Small and Large Magellanic Clouds have led to significant infall of metal-poor gas into the LMC, influencing its star formation and metallicity distribution.

Contribution

It demonstrates through simulations that gas from the SMC can be stripped and accreted into the LMC, explaining the origin of low-metallicity stars in the LMC.

Findings

Approximately 0.7% of SMC gas passed through LMC's center 1.3 Gyr ago.

About 18% of SMC gas passed through LMC's center 0.2 Gyr ago.

Replenished gas has a metallicity of [Fe/H] = -0.9 to -1.0.

Abstract

We first show that a large amount of metal-poor gas is stripped from the Small Magellanic Cloud (SMC) and fallen into the Large Magellanic Cloud (LMC) during the tidal interaction between the SMC, the LMC, and the Galaxy over the last 2 Gyrs. We propose that this metal-poor gas can closely be associated with the origin of LMC's young and intermediate-age stars and star clusters with distinctively low-metallicities with [Fe/H] < -0.6. We numerically investigate whether gas initially in the outer part of the SMC's gas disk can be stripped during the LMC-SMC-Galaxy interaction and consequently can pass through the central region (R<7.5 kpc) of the LMC. We find that about 0.7 % and 18 % of the SMC's gas can pass through the central region of the LMC about 1.3 Gyr ago and 0.2 Gyr ago, respectively. The possible mean metallicity of the replenished gas from the SMC to LMC is about [Fe/H] = -0.9 to -1.0 for the two interacting phases. These results imply that the LMC can temporarily replenish gas supplies through the sporadic accretion and infall of metal-poor gas from the SMC. These furthermore imply that if these gas from the SMC can collide with gas in the LMC to form new stars in the LMC, the metallicities of the stars can be significantly lower than those of stars formed from gas initially within the LMC.