A Catalog of Merging Dwarf Galaxies in the Local Universe

Abstract

We present the largest publicly available catalog of interacting dwarf galaxies. It includes 177 nearby merging dwarf galaxies of stellar mass M * < 10 10 M and redshifts z < 0.02. These galaxies are selected by visual inspection of publicly available archival imaging from two wide-field optical surveys (SDSS III and the Legacy Survey), and they possess low surface brightness features that are likely the result of an interaction between dwarf galaxies. We list UV and optical photometric data which we use to estimate stellar masses and star formation rates. So far, the study of interacting dwarf galaxies has largely been done on an individual basis, and lacks a sufficiently large catalog to give statistics on the properties of interacting dwarf galaxies, and their role in the evolution of low mass galaxies. We expect that this public catalog can be used as a reference sample to investigate the effects of the tidal interaction on the evolution of star-formation, morphology/structure of dwarf galaxies.Our sample is overwhelmingly dominated by star-forming galaxies, and they are generally found significantly below the red-sequence in the color-magnitude relation. The number of early-type galaxies is only 3 out of 177. We classify them, according to observed low surface brightness features, into various categories including shells, stellar streams, loops, antennae or simply interacting. We find that dwarf-dwarf interactions tend to prefer the low density environment. Only 41 out of the 177 candidate dwarf-dwarf interaction systems have giant neighbors within a sky projected distance of 700 kpc and a line of sight radial velocity range ±700 km/s and, compared to the LMC-SMC, they are generally located at much larger sky-projected distances from their nearest giant neighbor.

Study of Star Formation Rate and Metallicity of an Interacting Dwarf Galaxy NGC 2604

“…We selected a system of interacting dwarf galaxy NGC 2604 having a low redshift of z = 0.0069 from the catalog compiled by Poudel et al (2018). The galaxy NGC 2604 is an interacting galaxy located at R.A. (J2000) = 128.3457 0 , Dec. (J2000) = 29.5386 0 (Fig.…”

“…For H α line, the intensity was maximum. Using the adopted distance to the galaxy D = 29.29 Mpc (Poudel et al, 2018), we calculated R = D × 3.08 × 10 24 cm = 29.29 × 3.08 × 10 24 cm = 90.21 × 10 24 cm. Star formation rate using H α line was calculated by using equation (2).…”

Star Formation in Isolated Dwarf Galaxies Hosting Tidal Debris: Extending the Dwarf–Dwarf Merger Sequence

“…To ensure that the inclusion of such ambiguous cases does not bias our results, we visually inspect the automated sample and construct a "visual sample" subset that consists of only tidal feature systems that are unambiguously the result of a merger with another dwarf galaxy. We follow the benchmarks set forward in Paudel et al (2018), and generally look for the morphology of the detected LSB feature to be inconsistent with extended irregular structure or flocculent spiral arms.…”

“…We adopt the isolation criterion of Paudel et al (2018) because the scope of the work was to identify mergers between dwarf galaxies. Paudel et al (2018) required that the dwarf be separated by at least 700 kpc in projection and 700 km s −1 from its nearest massive neighbor, where we adopt a mass cut of M > 4 × 10 10 M such that the median stellar mass of the massive neighbors coincides with that reported by Paudel et al (2018). This method produces a sample of 231 isolated dwarfs, as compared to 226 in the original isolated sample.…”

MCG+07-20-052: Interacting Dwarf Pair in a Group Environment

“…INTERACTING DWARF As our primary interest is to find low-mass interacting galaxies in the nearby Universe, we carried out a systematic search for such objects in the local volume (z < 0.02). We published the most extended catalog of interacting dwarf galaxies (Paudel et al 2018b), which comprises 177 interacting dwarf galaxies. These galaxies are selected by visual inspection of color images of the two wide-field optical surveys (SDSS-III and the Legacy Survey).…”