Dust in galaxies Galaxy Zoo

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hst image of ngc 3314, example of overlapping galaxy.


the properties of galactic dust have been examined in several galaxy zoo papers. interstellar medium of spiral galaxies filled gas , small solid particles called dust grains. despite constituting minor fraction of galactic mass (between 0.1% , 0.01% milky way), dust grains have major role in shaping appearance of galaxy. because of dimension (typically smaller few tenths of micron), effective in absorbing , scattering radiation emitted stars in ultraviolet, optical , near-infrared. although interstellar regions more devoid of matter vacuum artificially created on earth, there matter in space. these regions have low densities , consist of gas (99%) , dust. in total, approximately 15% of visible matter in milky way composed of interstellar gas , dust.


the study of dust in galaxies interesting many reasons. example, dimming effects of dust need corrected estimate total mass of galaxy measurements of light. standard candles used measure expansion history of universe need corrected dust extinction.


a catalogue of 1,990 overlapping galaxies published in 2013, had been collected volunteers on galaxy zoo forum using sdss images. abstract states: analysis of galaxies overlapping images offers direct way probe distribution of dust extinction , effects on background light. catalogue used in study of ultraviolet attenuation laws.








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