A search for ultra-compact dwarf galaxies in the NGC 1023 group of galaxies
نویسندگان
چکیده
We present a photometric search for UCD candidates in the nearby galaxy group NGC 1023 (d=11 Mpc) – the poorest environment searched for UCDs yet –, based on wide field imaging with CFHT. After photometric and morphological selection, we obtain a sample of 21 UCD candidates with −12 < MV < −11 mag, if located at NGC 1023’s distance. From spectroscopy taken at Calar Alto observatory, we identify the UCD candidate in closest projection to NGC 1023 as an emission line background galaxy. Our photometric data show that in the NGC 1023 group, the mass spectrum of analogs to Fornax/Virgo UCD is restricted to 1/4 of the maximum Fornax/Virgo UCD mass. More spectroscopy is needed to further constrain the mass range of UCDs in this galaxy group.
منابع مشابه
Galaxy threshing and the formation of ultra-compact dwarf galaxies
Recent spectroscopic and morphological observational studies of galaxies around NGC 1399 in the Fornax Cluster (Drinkwater et al. 2000b) have discovered several ‘ultra-compact dwarf’ galaxies with intrinsic sizes of ∼ 100 pc and absolute B band magnitudes ranging from −13 to −11 mag. In order to elucidate the origin of these enigmatic objects, we perform numerical simulations on the dynamical e...
متن کاملPulsating red giant and supergiant stars in the Local Group dwarf galaxy Andromeda I
We have conducted an optical long-term monitoring survey of the majority of dwarf galaxies in the Local Group, with the Isaac Newton Telescope (INT), to identify the long period variable (LPV) stars. LPV stars vary on timescales of months to years, and reach the largest amplitudes of their brightness variations at optical wavelengths, due to the changing temperature. They trace stellar populati...
متن کاملThe Dwarf Galaxy Population in Nearby Groups. the Data
We used V and I CCD photometry to search for low-surface brightness dwarf galaxies in the central (< 0.5 h Mpc) region of the loose groups NGC 6868 (Telescopium) and NGC 5846, the compact group HCG 42 and the poor cluster IC 4765. We used the parameters given by the exponential profile fit (central surface brightness, scale length and limiting diameter) to identify 80 low surfacebrightness dwar...
متن کاملDASTWAR: a tool for completeness estimation in magnitude-size plane
Today, great observatories around the world, devote a substantial amount of observing time to sky surveys. The resulted images are inputs of source finder modules. These modules search for the target objects and provide us with source catalogues. We sought to quantify the ability of detection tools in recovering faint galaxies regularly encountered in deep surveys. Our approach was based on com...
متن کاملFaint Fuzzies and the Formation of Lenticular Galaxies
We investigate the dynamical state of a new class of extended star clusters, known as ”Faint Fuzzies”, that were discovered in two nearby S0 galaxies, NGC 1023 and NGC 3384. It is shown that the Faint Fuzzies of NGC 1023 lie in a fast rotating ring-like structure within the galactic disk with mean radius of 5 kpc, rotational velocity of 200 km/s and velocity dispersion of 115 km/s. We propose a...
متن کامل