Optical broadband BVRI observations of 54 galaxies selected from the Catalog of Isolated Triplets of Galaxies in the Northern Hemisphere have been carried out at San Pedro Mártir National Observatory to evaluate their photometric and morphological properties. We complement our analysis with Two-Micron All Sky Survey (2MASS) and Sloan Digital Sky Survey (SDSS) images and look for signatures likely related to interactions/mergers. We report apparent/absolute BVRI magnitudes and colors for the 54 galaxies. The membership of these galaxies is re-evaluated by imposing a reasonable condition of concordant redshifts upon the original selection criteria, rendering a final sample of 34 galaxies in 13 triplets, 12 galaxies in close pairs, and 8 galaxy outliers. The triplets are spiral-dominated systems in different dynamical stages from loosely interacting to almost merged objects. The incidence fraction of features likely associated with interactions is ~56%, similar to those found in northern and southern compact groups. The average fraction of bars is 35% with a mean value of maximum bar ellipticity max ≈ 0.4. Bars are hosted in the late-type triplet spirals, almost twice more than in early-type spirals. The global fraction of rings is 20%, all in the late-type components. The overdensity of triplets with respect to the background and their current dynamical status, as devised from our estimate of their dynamical parameters, namely the harmonic radius RH , velocity dispersion σ, dimensionless crossing time H 0τ c , and virial mass MV , appear to be sufficient to favor galaxy transformations similar to those seen in dense groups and clusters. By contrast, the lower fraction of bonafide ellipticals and the relatively higher fraction of late-type spirals make these triplets essentially different from the Hickson Compact Groups and more representative of the field. A modest 1.6 enhancement factor in the optical luminosity of the late-type triplet components relative to an isolated galaxy control sample is also interpreted as consistent with interactions in physically bounded aggregates. Our results lead us to suggest that non-negligible populations of physical triplets might be found in complete and well-observed samples. We provide individual mosaics for the 54 galaxies containing (1) logarithmic-scaled R-band images, (2) R-band sharp/filtered images, (3) (B – I) color index maps, (4) RGB images from the SDSS database, (5) co-added J + H + K images generated from the 2MASS archives that were also sharp/filtered, and (6) , position angle radial profiles from a surface photometry analysis of (a) the R band and (b) the co-added near-infrared images, all used for the present analysis.
展开▼
机译：San PedroMártir国家天文台已对从北半球孤立三重星系目录中选出的54个星系进行了宽带BVRI光学观测，以评估它们的光度和形态特性。我们用两微米全天候测量（2MASS）和斯隆数字天文学测量（SDSS）图像来补充我们的分析，并寻找可能与交互/合并相关的签名。我们报告了54个星系的表观/绝对BVRI大小和颜色。通过在原始选择标准上施加一致的红移的合理条件，重新评估这些星系的成员资格，最终得出13个三重态中的34个星系，成对的12个星系和8个星系离群值的最终样本。三元组是从松散相互作用到几乎合并的对象，处于不同动力学阶段的螺旋控制系统。可能与相互作用相关的特征的发生率约为56％，与北部和南部致密群中发现的相似。条的平均分数为35％，最大条椭圆率max≈0.4。条形图放置在晚期类型的三重螺旋中，几乎是早期类型中的两倍多。环的总分数为20％，全部在后期类型的组件中。根据我们对它们的动力学参数（即谐波半径RH，速度色散σ，无因次穿越时间H0τc和病毒质量MV）的估计，三胞胎相对于背景及其当前动力学状态的过密度似乎是足以支持类似于在密集群体和星团中看到的星系转换。相比之下，较低比例的纯正椭圆形和较高比例的后期螺旋形使这些三元组与希克森致密基团本质上不同，并且更具代表性。相对于孤立的银河系对照样品，晚型三重态组分的光度的适度1.6增强因子也被解释为与物理结合的聚集体中的相互作用一致。我们的结果使我们建议，在完整且观察良好的样本中可能会发现不可忽略的三胞胎种群。我们为54个星系提供了单独的镶嵌图，其中包括（1）对数缩放的R带图像，（2）R带清晰/滤波图像，（3）（B – I）颜色索引图，（4）来自SDSS数据库，（5）共添加了从2MASS存档生成的J + H + K图像，这些图像也经过了清晰/过滤，（6）是根据（a）R波段和（ b）共加的近红外图像，全部用于本分析。
展开▼
