Dwarf Galaxies in the Local Volume

Abstract

We review observational data about a sample of Local Volume objects containing about 1000 galaxies within 11 Mpc of the Milky Way. Dwarf galaxies with stellar masses M * /M ⊙ < 9 dex make up 5/6 of the sample. Almost 40% of them have their distances measured with high precision using the Hubble Space Telescope. Currently, the LV is the most representative and least selection-affected sample of dwarf galaxies suitable for testing the standard ΛCDM paradigm at the shortest cosmological scales. We discuss the H II properties of dwarf galaxies in different environments and the star formation rates in these systems as determined from F U V-and Hα-survey data. We also pay certain attention to the baryonic Tully-Fisher relation for low-mass dwarf galaxies. We also point out that LV dwarfs are important "tracers" for determining the total masses of nearby groups and the nearest Virgo cluster.

The Interstellar Medium of Dwarf Galaxies

“…Half of these are located near major galaxies like the Milky Way or M 81. While spheroidal dwarfs show a tendency to be located in more crowded environments, there also exist rare exceptions from this rule with dSphs quite far from any major source, but being nevertheless devoid of a significant interstellar medium [17]. HI is detected in 91% (424/467) of the HI observed late-type but only in 7% (13/180) of the HI observed early-type dwarfs.…”

“…Green peas are even rarer than BCDs and are therefore commonly observed at redshifts z > 0.1. Not surprisingly, dIrrs preferentially reside in field environments, while dEs are more commonly found in denser more clustered regions (e.g., [15,17]; for the Virgo cluster, see e.g., [22]). The latter also holds for the relatively luminous nucleated dwarfs.…”

“…Some of them, like the SMC, owe their shape to a recent interaction with another galaxy. The majority of this class of objects is characterized by a massive interstellar medium that is dominated by neutral hydrogen (HI; see e.g., [17]). Among this class of late-type objects, blue compact dwarf galaxies (BCDs) stand out because they host sites of recent or ongoing massive star formation, 1 by a high surface brightness, e.g., µ B,peak < 22 m /arcsec 2 , and blue color, e.g., µ B,peak − µ R,peak < ∼ 1 m .…”

“…Over the last 10 to 15 years, the most important of these include FIGGS (Faint Irregular Galaxies GMRT Survey; [37]) with the Giant Meter Radio Telescope covering ≈60 nearby (D < ∼ 4 Mpc) dwarfs and the JVLA (Jansky Very Large Array) projects THINGS (The HI Nearby Galaxy Survey; [38]) with 12 dwarfs among the 34 targeted sources, SHIELD (Survey of HI in Extremely Low mass Dwarfs; [39]) with 12 sources, and the JVLA-ANGST survey (Very Large Array survey of ACS Nearby Galaxy Survey Treasury galaxies; [40]) encompassing 35 dwarfs at D < ∼ 4 Mpc. The Little Things survey (Local Irregulars That Trace Luminosity Extremes; [41]), again obtained with the JVLA, presents observations of 37 dwarf irregulars and 4 BCDs, while a compilation of local volume objects (distance D < 11 Mpc), comprising a total of 1072 galaxies, among them many dwarfs, has been presented by [17].…”

Специальный Сводный Каталог Карликовых Галактик Во Вселенной До Расстояний 121 Мпк

“…В работах Караченцева и его коллегами [10 19] изучены различные проблемы по карликовым галактикам. Например, в работе [19] авторы пред ставляют обзор наблюдательных данных о вы борке Местного объема, которая содержит около 1000 галактик в пределах 11 Мпк вокруг Млечно го Пути. Они обсуждают HII-свойства карлико вых галактик в различном окружении, а также темпы звездообразования в них, полученные по данным FUV-и Hα-обзоров.…”