标题： 基于深近红外观测的六例本地星系团矮星系的 photometric 性质 显示英文标题

标题： Photometric Properties of Six Local Volume Dwarf Galaxies from Deep Near-Infrared Observations

摘要： 我们获得了六个矮星系样本的深度近红外 $J$-波段（1.25 $\mu$微米）、$H$-波段（1.65$ \mu$微米）和$K_s$-波段（2.15 $\mu$微米）成像，这些矮星系位于本星系群（LV，$D\la10$兆秒差距）中（绝对星等$M_B\ga-17$魔术值）。 该样本主要由发现于本地宇宙（LV）各种环境中的早期类型的矮星系组成。样本中有两颗星系（LEDA 166099 和 UGCA 200）首次在近红外波段被探测到。深场近红外图像允许我们详细研究每颗星系的光度和结构特性。星系的表面亮度分布一直测量到约$24 mag arcsec^{-2}$等亮度线，在$J$和$H$波段，以及$K_s$波段的$23 mag arcsec^{-2}$等亮度线处。星系的总星等在三个波长带内得到确定。对于样本中最亮的星系（$M_B\la-15.5$星等），我们发现“两微米全天巡天”（2MASS）低估了这些系统的总星等，最多可达$\la0.5$星等。通过指数函数（针对具有恒星盘的星系）或 Sérsic 函数拟合星系的径向表面亮度分布，以推导出其潜在恒星成分的结构。 特别是，有效面亮度（$\mu_e$）和有效半径（$r_e$）是通过拟合表面亮度分布曲线得到的。 星系的（$J$-$K_s$）颜色已被测量，以探索早期类型的矮星系的光度-金属丰度关系。 此外，星系的（$B$-$K_s$）颜色被用来评估它们相对于其他星系形态的演化状态。 矮星系的总恒星质量是根据（$H$）波段的测光测量得出的。 这些结果随后将与星系的动力学质量估计值进行比较，以确定它们的暗物质含量。 显示英文摘要

摘要： We have obtained deep near-infrared $J$- (1.25 $\mu$m), $H$- (1.65$ \mu$m) and $K_s$-band (2.15 $\mu$m) imaging for a sample of six dwarf galaxies ($M_B\ga-17$ mag) in the Local Volume (LV, $D\la10$ Mpc). The sample consists mainly of early-type dwarf galaxies found in various environments in the LV. Two galaxies (LEDA 166099 and UGCA 200) in the sample are detected in the near-infrared for the first time. The deep near-infrared images allow for a detailed study of the photometric and structural properties of each galaxy. The surface brightness profiles of the galaxies are detected down to the ~$24 mag arcsec^{-2}$ isophote in the $J$- and $H$-bands, and $23 mag arcsec^{-2}$ in the $K_s$-band. The total magnitudes of the galaxies are derived in the three wavelength bands. For the brightest galaxies ($M_B\la-15.5$ mag) in the sample, we find that the Two Micron All Sky Survey (2MASS) underestimates the total magnitudes of these systems by up to $\la0.5$ mag. The radial surface brightness profiles of the galaxies are fitted with an exponential (for those galaxies having a stellar disk) or S\'ersic law to derive the structure of the underlying stellar component. In particular, the effective surface brightness ($\mu_e$) and effective radius ($r_e$) are determined from the analytic fits to the surface brightness profile. The $J$-$K_s$ colours for the galaxies have been measured to explore the luminosity-metallicity relation for early-type dwarfs. In addition, the $B$-$K_s$ colours of the galaxies are used to assess their evolutionary state relative to other galaxy morphologies. The total stellar masses of the dwarf galaxies are derived from the $H$-band photometric measurements. These will later be compared to the dynamical mass estimates for the galaxies to determine their dark matter content.