The Ongoing Growth of the M87 Halo through Accretion EventsReport as inadecuate




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1

Max-Planck-Institut fuer extraterrestrische Physik, Giessenbachstr.1, 85748 Garching, Germany

2

ESO, Karl-Schwarzschild-Str.2, 85748 Garching, Germany



These authors contributed equally to this work.





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Author to whom correspondence should be addressed.



Academic Editors: José Alfonso López Aguerri, Enrichetta Iodice and Alexei Moiseev

Abstract Planetary nebulas PNs offer a unique tool to investigate the outer regions of massive galaxies because their strong OIIIλ5007Å emission line makes them detectable out to several effective radii from the galaxy’s centre. We use a deep and extended spectroscopic survey of PNs ∼300 objects to study the spatial distribution, the kinematics and the stellar populations in the extended outer halo of the bright elliptical galaxy M87 NGC 4486 in the Virgo cluster. We show that in the Virgo core, M87 stellar halo and the intracluster light are two distinct dynamical components, with different velocity distributions. Moreover the synergy of the PN kinematical information and the deep V-B-band photometry revealed an ongoing accretion event in the outer regions of M87. This satellite accretion represents a non-negligible perturbation of the halo properties: beyond 60 kpc the M87 halo is still growing with 60% of its light being added by the accretion event at the distance where it is detected. View Full-Text

Keywords: clusters: individual: Virgo; galaxies: halos; galaxies: individual: M 87 NGC 4486; planetary nebulae: general clusters: individual: Virgo; galaxies: halos; galaxies: individual: M 87 NGC 4486; planetary nebulae: general





Author: Alessia Longobardi 1,* , Magda Arnaboldi 2,† and Ortwin Gerhard 1,†

Source: http://mdpi.com/



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