AI 中文总结
研究星系大小上限，以IC 1101为对象，通过超深成像、散射光建模减除及多剖面分析，得出其主体沿半主轴延伸至260 kpc，是已知最大星系且范围仍在扩大，处于质量-大小关系极端上端，还发现其周围与星系团介质扰动相关的特征。
AI 中文摘要
星系能达到的最大物理范围尚不清楚。在这方面，已知最大且质量最大的星系之一IC 1101为限制当前星系大小上限提供了宝贵机会。此前对该星系的深度成像证实其巨大，但未表明是否有边缘。我们利用对该星系拍摄的最深图像探索此问题，采用INT/WFC的超深g和r波段成像，达到μ = 30 mag arcsec^-2（在10 x 10 arcsec^2区域内3σ）。我们通过扩展PSF表征和基于小波的混合反卷积对恒星和星系自身的散射光进行建模和减除。通过不同位置角的表面亮度、颜色和恒星质量密度剖面组合，发现IC 1101主体沿半主轴延伸至Redge = 260 kpc（假设阿贝尔2029红移z = 0.077），包含3.4 x 10^12 M_sun恒星。此Redge是迄今测量的最大边缘半径之一，使IC 1101处于质量-大小关系的极端上端。此外，我们报告在星系周围有大量不对称、极低表面亮度特征，在空间上与通过对阿贝尔2029星系团X射线研究在星系团介质中观察到的大规模扰动一致，IC 1101就嵌于此星系团中。IC 1101直径约520 kpc，是迄今已知最大星系；但其外围显示出正在进行质量聚集的明显迹象，表明其空间范围仍在扩大。
英文摘要
The maximum physical extent that galaxies can reach is poorly understood. In this regard, IC 1101, one of the most extended and massive galaxies known, provides a valuable opportunity to constrain the upper limit of galaxy sizes at the present epoch. Previous deep imaging of the system confirmed its enormous extension, but did not indicate whether it has an edge. We explore this issue using the deepest images ever taken of this galaxy; ultra-deep g- and r- band imaging from the INT/WFC, reaching μ = 30 mag arcsec^-2 (3σ in an area equivalent to 10 x 10 arcsec^2). We model and subtract the scattered light from both stars and the galaxy itself using an extended PSF characterization and a hybrid wavelet-based deconvolution. Using a combination of surface brightness, colour, and stellar mass density profiles oriented at different position angles, we find that the main body of IC 1101 extends to Redge = 260 kpc along the semi-major axis (assuming the redshift of Abell 2029, z = 0.077), enclosing 3.4 x 10^12 M_sun in stars. This Redge is among the largest edge radii measured for any galaxy to date, placing IC 1101 at the extreme upper end of the mass-size relation. In addition, we report a large number of asymmetrical, very low surface brightness features around the galaxy that are spatially consistent with the large-scale disturbances observed in the intracluster medium through X-ray studies of the Abell 2029 cluster, in which IC 1101 is embedded. With a confirmed diameter of around 520 kpc, IC 1101 stands as the largest galaxy known to date; yet, its outskirts show clear signatures of ongoing mass assembly, indicating that its spatial extent is still growing.
Comments20 pages, 15 figures. Accepted for publication in Astronomy and Astrophysics. Corrected typos
