The Dust-to-Gas Ratio in the Small Magellanic Cloud Tail

TL;DR

This study measures the dust-to-gas ratio in the Small Magellanic Cloud Tail using infrared observations, revealing higher ratios than expected and suggesting dust destruction and recent tidal stripping of the region.

Contribution

First measurement of the gas-to-dust ratio in the SMC Tail using Spitzer data, indicating dust destruction and recent tidal origin.

Findings

Gas-to-dust ratio in the Tail is ~1200, higher than expected.

Localized ratios of ~440 and ~250 suggest dust formation or ionized gas.

Results support the Tail being a recently stripped tidal feature.

Abstract

The Tail region of the Small Magellanic Cloud (SMC) was imaged using the MIPS instrument on the Spitzer Space Telescope as part of the SAGE-SMC Spitzer Legacy. Diffuse infrared emission from dust was detected in all the MIPS bands. The Tail gas-to-dust ratio was measured to be 1200 +/- 350 using the MIPS observations combined with existing IRAS and HI observations. This gas-to-dust ratio is higher than the expected 500-800 from the known Tail metallicity indicating possible destruction of dust grains. Two cluster regions in the Tail were resolved into multiple sources in the MIPS observations and local gas-to-dust ratios were measured to be ~440 and ~250 suggests dust formation and/or significant amounts of ionized gas in these regions. These results support the interpretation that the SMC Tail is a tidal tail recently stripped from the SMC that includes gas, dust, and young stars.