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arXiv 2403.04850astro-ph.GA
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基于强引力透镜高分辨率ALMA观测的三个椭圆星系的复杂角结构

Complex angular structure of three elliptical galaxies from high-resolution ALMA observations of strong gravitational lenses

H. R. Stacey, D. M. Powell, S. Vegetti, J. P. McKean, C. D. Fassnacht, D. Wen, C. M. O'Riordan

AI总结:

本研究利用ALMA高分辨率观测三个强透镜星系,通过多极展开联合推断透镜质量与源面亮度,发现透镜存在显著高阶角结构,暗示暗物质对星系角结构有贡献。

摘要:

长期以来,人们一直认为星系尺度强透镜的大尺度质量分布可以用带有外部剪切的奇异椭球幂律密度剖面很好地描述。然而,该模型的刚性可能导致利用引力透镜观测值推断的天体物理参数出现系统误差。本文中,我们利用阿塔卡马大型(亚)毫米波阵列(Atacama Large (sub-)Millimetre Array,ALMA)对三个强透镜尘埃恒星形成星系进行了角分辨率约30毫角秒的观测,并探究了这些数据对透镜星系角结构的敏感度。我们借助一项为干涉测量数据开发的技术,通过最高至四阶的幂律密度剖面多极展开,联合推断了透镜质量分布和被透镜源的完整面亮度。三组数据集均强烈支持三阶与四阶多极振幅约为会聚度的1%。尽管其中一个透镜系统的红外恒星等光强线与等密度形状吻合,但另外两个系统的等光强线存在不同程度的差异,表明透镜星系内部或外部的暗物质对角结构有贡献。

英文摘要:

The large-scale mass distributions of galaxy-scale strong lenses have long been assumed to be well-described by a singular ellipsoidal power-law density profile with external shear. However, the inflexibility of this model could lead to systematic errors in astrophysical parameters inferred with gravitational lensing observables. Here, we present observations with the Atacama Large (sub-)Millimetre Array (ALMA) of three strongly lensed dusty star-forming galaxies at $\simeq30$ mas angular resolution and investigate the sensitivity of these data to angular structure in the lensing galaxies. We jointly infer the lensing mass distribution and the full surface brightness of the lensed sources with multipole expansions of the power-law density profile up to fourth order using a technique developed for interferometric data. All three data sets strongly favour third and fourth-order multipole amplitudes of $\approx1$ percent of the convergence. While the infrared stellar isophotes and isodensity shapes agree for one lens system, for the other two the isophotes disagree to varying extents, suggesting contributions to the angular structure from dark matter intrinsic or extrinsic to the lensing galaxy.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

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