论文标题
从螺旋到凸线：来自三个早期型星系的旋转曲线和质量模型的证据
From spirals to lenticulars: evidence from the rotation curves and mass models of three early-type galaxies
论文作者
论文摘要
传统上，旋转曲线很难追踪早期型星系（ETG），因为它们通常像晚期星系（LTG）一样缺乏高密度的冷气盘。我们从ATLAS3D调查中得出了三个凸耳星系的旋转曲线，将内部部分中的CO数据与外部区域的深HI数据相结合，延伸到10-20个有效半径。我们还使用3.6 UM的Spitzer光度法将旋转曲线分解为重子和暗物质（DM）的贡献。我们发现（1）这些ETG的旋转形状与具有相似质量和表面亮度的LTG相似； （2）动态$ - $推断出的恒星质量与光的比率很小，对于静态ETG，但与星形LTG相似； （3）DM光晕遵循与星系光度与LTG相同的缩放关系； （4）一个星系（NGC 3626）的cuspy DM剖面拟合不佳，这表明DM核心也可能存在于高质量星系中。我们的结果表明，这些凸耳星系最近已从LTG转变为ETG，而没有改变其DM光环结构（例如，通过主要合并），并且可能是褪色的。我们还确认ETG遵循与LTG相同的径向加速关系，这加强了这样一种观念，即这是所有星系类型的普遍定律。
Rotation curves have traditionally been difficult to trace for early-type galaxies (ETGs) because they often lack a high-density disk of cold gas as in late-type galaxies (LTGs). We derive rotation curves for three lenticular galaxies from the ATLAS3D survey, combining CO data in the inner parts with deep HI data in the outer regions, extending out to 10-20 effective radii. We also use Spitzer photometry at 3.6 um to decompose the rotation curves into the contributions of baryons and dark matter (DM). We find that (1) the rotation-curve shapes of these ETGs are similar to those of LTGs of similar mass and surface brightness; (2) the dynamically$-$inferred stellar mass-to-light ratios are small for quiescent ETGs but similar to those of star-forming LTGs; (3) the DM halos follow the same scaling relations with galaxy luminosity as those of LTGs; (4) one galaxy (NGC 3626) is poorly fitted by cuspy DM profiles, suggesting that DM cores may exist in high-mass galaxies too. Our results indicate that these lenticular galaxies have recently transitioned from LTGs to ETGs without altering their DM halo structure (e.g., via a major merger) and could be faded spirals. We also confirm that ETGs follow the same radial acceleration relation as LTGs, reinforcing the notion that this is a universal law for all galaxy types.
