We present here far-infrared photometry of galaxies in a sample that is relatively unexplored at these wavelengths: low-metallicity dwarf galaxies with moderate star formation rates. Four dwarf irregular galaxies from the Little Things survey are considered, with deep Herschel PACS and SPIRE observations at 100, 160, 250, 350, and 500 μm. Results from modified blackbody fits indicate that these galaxies have low dust masses and cooler dust temperatures than more actively star-forming dwarfs, occupying the lowest L _TIR and M _dust regimes seen among these samples. Dust-to-gas mass ratios of ∼10⁻⁵ are lower, overall, than in more massive and active galaxies but are roughly consistent with the broken power-law relation between the dust-to-gas ratio and metallicity found for other low-metallicity systems. Chemical evolution modeling suggests that these dwarf galaxies are likely forming very little dust via stars or grain growth and have very high dust destruction rates.

我们在此展示了在这些波长下相对未探索的样本中星系的远红外光度测量：具有中等恒星形成率的低金属度矮星系。考虑了来自Little Things调查的四个矮不规则星系，在100、160、250、350 和 500 μ m处进行了深赫歇尔 PACS 和 SPIRE 观测。修改后的黑体拟合结果表明，与更活跃的恒星形成矮星相比，这些星系的尘埃质量低，尘埃温度更低，占据了这些样本中最低的L _TIR和M _尘埃区域。粉尘与气体的质量比约为 10 ^-5总体而言，比质量更大和更活跃的星系要低，但与在其他低金属丰度系统中发现的尘埃气体比和金属丰度之间的幂律关系大体一致。化学演化模型表明，这些矮星系可能通过恒星或颗粒生长形成的尘埃很少，并且尘埃破坏率非常高。