000227027 001__ 227027
000227027 005__ 20181203024624.0
000227027 0247_ $$2doi$$a10.1093/mnras/stw2103
000227027 022__ $$a0035-8711
000227027 02470 $$2ISI$$a000393566000052
000227027 037__ $$aARTICLE
000227027 245__ $$aASTErIsM: application of topometric clustering algorithms in automatic galaxy detection and classification
000227027 260__ $$bOxford Univ Press$$c2016$$aOxford
000227027 269__ $$a2016
000227027 300__ $$a19
000227027 336__ $$aJournal Articles
000227027 520__ $$aWe present a study on galaxy detection and shape classification using topometric clustering algorithms. We first use the DBSCAN algorithm to extract, from CCD frames, groups of adjacent pixels with significant fluxes and we then apply the DENCLUE algorithm to separate the contributions of overlapping sources. The DENCLUE separation is based on the localization of pattern of local maxima, through an iterative algorithm, which associates each pixel to the closest local maximum. Our main classification goal is to take apart elliptical from spiral galaxies. We introduce new sets of features derived from the computation of geometrical invariant moments of the pixel group shape and from the statistics of the spatial distribution of the DENCLUE local maxima patterns. Ellipticals are characterized by a single group of local maxima, related to the galaxy core, while spiral galaxies have additional groups related to segments of spiral arms. We use two different supervised ensemble classification algorithms: Random Forest and Gradient Boosting. Using a sample of similar or equal to 24 000 galaxies taken from the Galaxy Zoo 2 main sample with spectroscopic redshifts, and we test our classification against the Galaxy Zoo 2 catalogue. We find that features extracted from our pipeline give, on average, an accuracy of similar or equal to 93 per cent, when testing on a test set with a size of 20 per cent of our full data set, with features deriving from the angular distribution of density attractor ranking at the top of the discrimination power.
000227027 6531_ $$amethods: data analysis
000227027 6531_ $$amethods: statistical
000227027 6531_ $$acatalogues
000227027 6531_ $$agalaxies: elliptical and lenticular
000227027 6531_ $$acD
000227027 6531_ $$agalaxies: general
000227027 6531_ $$agalaxies: spiral
000227027 700__ $$uUniv Geneva, Dept Astron, ISDC Data Ctr Astrophys, Chemin Ecogia 16, CH-1290 Versoix, Switzerland$$aTramacere, A.
000227027 700__ $$0247585$$g239560$$aParaficz, D.
000227027 700__ $$uUniv Geneva, Dept Astron, ISDC Data Ctr Astrophys, Chemin Ecogia 16, CH-1290 Versoix, Switzerland$$aDubath, P.
000227027 700__ $$0246614$$g222189$$aKneib, J. -P.
000227027 700__ $$aCourbin, F.$$g166196$$0245072
000227027 773__ $$j463$$tMonthly Notices Of The Royal Astronomical Society$$k3$$q2939-2957
000227027 909C0 $$xU10933$$0252365$$pLASTRO
000227027 909CO $$pSB$$particle$$ooai:infoscience.tind.io:227027
000227027 917Z8 $$x103317
000227027 937__ $$aEPFL-ARTICLE-227027
000227027 973__ $$rREVIEWED$$sPUBLISHED$$aEPFL
000227027 980__ $$aARTICLE