Dwarf Galaxies in the M 81/82 Group. New Photometric Data

Abstract

We present a list of 39 dwarf galaxies of the M 81/82 group. Three different methods are applied to determine their apparent integral magnitude : digital processing, equidensitometry, and calculation according to the formulae of FISHER and TULLY. The plates used were obtained with the Tautenburg Schmidt telescope. For a distance of the group of 3.5 Mpc the absolute magnitudes of the dwarf galaxies investigated are -15m < M < -gmEs wird eine Liste von 39 Zwerggalaxien, die zur M 81/8~-Gruppe gehciren, vorgelegt. Drei verschiedene Methoden wurden zur Bestimmung der scheinbaren Integralhelligkeiten angewandt : digitale Flachenphotometrie, Aquidensitometrie und die Methode von FISCHER und TULLY. Es wurden Platten des Tautenburger Schmidt-Teleskopes benutzt. Bei einer Entfernung der Gruppe iron 3.5 Mpc liegen die absoluten Helligkeiten der untersuchten Zwerggalaxien in dem Helligkeitsinterval1 -15m < M < -gm.

Structure and stellar content of dwarf galaxies

“…7 × 11. 7 Börngen et al (1982), which is not well defined. We guess a magnitude of completeness is M lim B ≈ −12.…”

“…This list was prepared by Binggeli (Van Driel et al 1998) based on Börngen et al (1982Börngen et al ( , 1984 and Karachentseva et al (1985). A map showing the distribution of these objects on the sky can be found in Van Driel et al (1998).…”

“…It is quite nearby, with D ≈ 4 Mpc (Karachentsev & Tikhonov 1994), and approximately 2 times as rich as the LG (above a given absolute magnitude). Our principal knowledge of the dwarf galaxy population of the M 81 group is due to the extensive photographic survey of Börngen et al (1982) In our first observing campaign we did B and R imaging for essentially all (≈ 35) known dwarf members from Börngen et al's list. Paper II will present deep B, V, R, I photometry for a subsample of non-resolved (early-type) dwarfs.…”

Thick disks and halos of spiral galaxies M 81, NGC 55 and NGC 300

“…M 81 is the gravitationally dominant member of its group, consisting of about 30 types of galaxies (Börngen et al 1982(Börngen et al , 1984Karachentseva et al 1985). The galaxy is a suitable object for this study because of its close distance, D = 3.6 Mpc (Freedman et al 2001) and small inclination, which provide an opportunity to study the geometry of the stellar structures across the disk plane.…”

Luminosity Profiles of 6 Dwarf Galaxies in the M 81/82 Group

“…The morphological classification (column 8) has been done recently after the large-scale photographs of the M81/82 group dwarfs with the 6-meter telescope were obtained (BORNGEN et al 1984). In the last column the mean color indices of each object are given.…”