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Dust Content (dust + content)
Selected AbstractsIonized gas in E/S0 galaxies with dust lanesMONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY, Issue 4 2010Ido Finkelman ABSTRACT We report the results of multicolour observations of 30 E/S0 galaxies with dust lanes. For each galaxy we obtained broad-band images and narrow-band images using interference filters isolating the H,+[N ii] emission lines to derive the amount and morphology of dust and ionized gas. To improve the wavelength coverage we retrieved data from the Sloan Digital Sky Survey and Two Micron All Sky Survey and combined these with our data. Ionized gas is detected in 25 galaxies and shows in most cases a smooth morphology, although knots and filamentary structure are also observed in some objects. The extended gas distribution closely follows the dust structure, with a clear correlation between the mass of both components. An extinction law by the extragalactic dust in the dark lanes is derived and is used to estimate the dust content of the galaxies. The derived extinction law is used to correct the measured colours for intrinsic dust extinction and the data are fitted with a stellar population synthesis model. We find that the H, emission and colours of most objects are consistent with the presence of an ,old' stellar population (,10 Gyr) and a small fraction of a ,young' population (, 10,100 Myr). To check this we closely examine NGC 5363, for which archival Spitzer/Infrared Array Camera and Galaxy Evolution Explorer data are available, as a representative dust-lane E/S0 galaxy of the sample. [source] Radiative transfer in disc galaxies , IV.MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY, Issue 4 2010The effects of dust attenuation on bulge, disc structural parameters ABSTRACT Combining Monte Carlo radiative transfer simulations and accurate 2D bulge/disc decompositions, we present a new study to investigate the effects of dust attenuation on the apparent structural properties of the disc and bulge of spiral galaxies. We find that dust affects the results from such decompositions in ways which cannot be identified when one studies dust effects on bulge and disc components separately. In particular, the effects of dust in galaxies hosting pseudo-bulges might be different from those in galaxies hosting classical bulges, even if their dust content is identical. Confirming previous results, we find that disc scalelengths are overestimated when dust effects are important. In addition, we also find that bulge effective radii and Sérsic indices are underestimated. Furthermore, the apparent attenuation of the integrated disc light is underestimated, whereas the corresponding attenuation of bulge light is overestimated. Dust effects are more significant for the bulge parameters, and, combined, they lead to a strong underestimation of the bulge-to-disc ratio, which can reach a factor of 2 in the V band, even at relatively low galaxy inclinations and dust opacities. Nevertheless, it never reaches factors larger than about 3, which corresponds to a factor of 2 in bulge-to-total ratio. Such effect can have an impact on studies of the black hole/bulge scaling relations. [source] The large scale magnetic field configuration in the Sombrero galaxy , persistence during galaxy evolution?ASTRONOMISCHE NACHRICHTEN, Issue 5-6 2006M. Krause Abstract Radio polarization observations at 4.86 and 8.35 GHz of the nearby edge-on galaxy M 104 revealed a large-scale magnetic field in this early-type spiral. This is to our knowledge the first detection of a regular magntic field in an Sa galaxy in the radio range. The magnetic field orientation in M 104 is predominantly parallel to the disk but has also vertical components at larger z-distances from the disk, i.e. a field configuration typical for normal edge-on spiral galaxies. Bolometer observations at 345 GHz data pertain to the cold dust content of the galaxy. Despite the optical appearance of the object with the huge dust lane, its dust content is smaller than that of more late-type spirals. (© 2006 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source] | ||||||||||