4 research outputs found
H-alpha imaging of the Local Volume galaxies I. The NGC 6946 galaxy group
We present new H-alpha imaging of all known dwarf irregular companions to NGC
6946: UGC 11583, KK 251, KK 252, KKR 55, KKR 56, Cepheus 1, KKR 59, and KKR 60.
The galaxies span a range of blue absolute magnitudes of [-13.6, -17.6],
relative gas content of [0.1, 2.5] M_sun/L_sun, current star formation activity
of [0.2, 5.2]10^-2 M_sun yr^-1, and timescale to exhaust the current gas supply
of [6, 86] Gyr.Comment: 4 pages, 1 figure. accepted to Research Note in Astronomy and
Astrophysic
The stellar disk thickness of LSB galaxies
We present surface photometry results for a sample of eleven edge-on galaxies
observed with the 6m telescope at the Special Astrophysical Observatory
(Russia). The photometric scale length, scale height, and central surface
brightness of the stellar disks of our sample galaxies are estimated. We show
that four galaxies in our sample, which are visually referred as objects of the
lowest surface brightness class in the Revised Flat Galaxies Catalog, have bona
fide low surface brightness (LSB) disks. We find from the comparison of
photometric scales that the stellar disks of LSB galaxies are thinner than
those of high surface brightness (HSB) ones. There is a clear correlation
between the central surface brightness of the stellar disk and its vertical to
radial scale ratio. The masses of spherical subsystems (dark halo + bulge) and
the dark halo masses are obtained for the sample galaxies based on the
thickness of their stellar disks. The LSB galaxies tend to harbor more massive
spherical subsystems than the HSB objects, whereas no systematic difference in
the dark halo masses between LSB and HSB galaxies is found. At the same time,
the inferred mass-to-luminosity ratio for the LSB disks appears to be
systematically higher than for HSB disks.Comment: 33 pages with 17 Postscript figures, uses aastex.cls, accepted by Ap
Revised photometric distances to nearby dwarf galaxies in the IC 342/Maffei complex
The results of DAOPHOT photometry of several hundred stars in five
irregular galaxies are presented using V and I CCD frames, obtained with
the Nordic Optical Telescope under a 0.6 arcsec seeing. Based on the
brightest blue and red stars we estimate the following distances to the
galaxies: 3.2 Mpc for UGCAÂ 105, 2.6 Mpc for UGCA 86, 1.8 Mpc for UGCA 92,
1.7 Mpc for NGCÂ 1569, and 1.7 Mpc for Cas 1. The problem of membership of
the galaxies to the IC 342/Maffei complex is briefly
discussed