标题： LIGHTS. 一种识别星系边缘的鲁棒技术 显示英文标题

标题： LIGHTS. A robust technique to identify galaxy edges

摘要： LIGHTS调查正在以与十年后时空遗产调查（LSST）将产生的深度和空间分辨率相当的方式成像星系（即，$\sim$31 星等/角秒$^2$； 3$\sigma$在相当于 10$^{\prime\prime}$$\times$ 10$^{\prime\prime}$的区域中）。这使得有可能以我们过去无法实现的精度探测星系的边缘，即原位恒星形成的最远位置。传统上，星系边缘是通过椭圆平均或视觉检查在一维中分析的。我们的方法允许对星系边缘进行二维探索，这对于理解偏离盘对称性的现象以及环境对星系生长的影响至关重要。在本文中，我们提出了一种新方法，利用星系表面质量密度图的二阶导数来确定其边缘。当有深空成像时，这为传统的边缘检测方法提供了一种稳健的定量替代方案。我们的技术结合了维纳-亨特去卷积法，通过星系自身去除点扩散函数（PSF）的影响。 通过将我们的方法应用于LIGHTS星系NGC 3486，我们确定了边缘位于205$^{\prime\prime}$ $\pm$ 5$^{\prime\prime}$。在此半径处，恒星表面质量密度为$\sim$1 M$_\odot$/pc$^2$，这支持了星系边缘与原位恒星形成阈值之间的潜在联系。 我们的对NGC 3486的二维分析显示边缘不对称性为$\sim$5$\%$。 这些技术对于在超深调查（如LSST、Euclid和Roman）中进行物理上有根据的星系大小确定将具有决定性的重要性。 显示英文摘要

摘要： The LIGHTS survey is imaging galaxies at a depth and spatial resolution comparable to what the Legacy Survey of Space and Time (LSST) will produce in 10 years (i.e., $\sim$31 mag/arcsec$^2$; 3$\sigma$ in areas equivalent to 10$^{\prime\prime}$$\times$ 10$^{\prime\prime}$). This opens up the possibility of probing the edge of galaxies, as the farthest location of in-situ star formation, with a precision that we have been unable to achieve in the past. Traditionally, galaxy edges have been analyzed in one-dimension through ellipse averaging or visual inspection. Our approach allows for a two-dimensional exploration of galaxy edges, which is crucial for understanding deviations from disc symmetry and the environmental effects on galaxy growth. In this paper, we propose a novel method using the second derivative of the surface mass density map of a galaxy to determine its edges. This offers a robust quantitative alternative to traditional edge-detection methods when deep imaging is available. Our technique incorporates Wiener-Hunt deconvolution to remove the effect of the Point Spread Function (PSF) by the galaxy itself. By applying our methodology to the LIGHTS galaxy NGC 3486, we identify the edge at 205$^{\prime\prime}$ $\pm$ 5$^{\prime\prime}$. At this radius, the stellar surface mass density is $\sim$1 M$_\odot$/pc$^2$, supporting a potential connection between galaxy edges and a threshold for in-situ star formation. Our two-dimensional analysis on NGC 3486 reveals an edge asymmetry of $\sim$5$\%$. These techniques will be of paramount importance for a physically motivated determination of the sizes of galaxies in ultra-deep surveys such as LSST, Euclid and Roman.