The GALEX Ultraviolet Virgo Cluster Survey (GUViCS) VIII. Diffuse dust in the Virgo intra-cluster space

A. Longobardi; A. Boselli; S. Boissier; S. Bianchi; P. Andreani; E. Sarpa; A. Nanni; M. Miville-Deschenes

doi:10.1051/0004-6361/201937024

paper

The GALEX Ultraviolet Virgo Cluster Survey (GUViCS) VIII. Diffuse dust in the Virgo intra-cluster space

arXiv:2001.05512 · doi:10.1051/0004-6361/201937024

Abstract

We present the first detection of diffuse dust in the intra-cluster medium of the Virgo cluster out to $\sim$ 0.4 virial radii, and study the radial variation of its properties on a radial scale of the virial radius. Analysing near-UV - $i$ colours for a sample of $\sim 12000$ background galaxies with redshifts $0.02 < z < 0.8$ , we find significant colour reddening and relate it to variation in $E (B - V)$ values. The $E (B - V)$ mean profile shows a dust component characterised by an average reddening $E (B - V) \sim 0.042 \pm 0.004$ mag within 1.5 degrees ( $\sim 0.3 r_{v i r}$ ) from the cluster centre. Assuming a Large Magellanic Cloud extinction law, we derive an average visual extinction $A_{V} = 0.14 \pm 0.01$ for a total dust mass, $M_{d} = 2.5 \pm 0.2 \times 1 0^{9} M_{⊙}$ , hence a dust-to-gas mass ratio $M_{d} / M_{g} = 3.0 \pm 0.3 \times 1 0^{- 4}$ . Based on the upper limits on the flux density $I_{250 μ m} = 0.1 MJys r^{- 1}$ derived from $H er sc h e l$ data, we estimate an upper limit for the dust temperature of $T_{d} \sim 10 K$ . However, similar densities can be obtained with dust at higher temperatures with lower emissivities. The Virgo cluster has diffuse dust in its intra-cluster medium characterised by different physical properties as those characterising the Milky Way dust. The diffuse dust in Virgo is transported into the cluster space through similar phenomena (stripping) as those building up the optical intra-cluster light, and it constitutes an additional cooling agent of the cluster gas.

arXiv comment5 pages, 3 figures, accepted as letter to the editor on A&A

The GALEX Ultraviolet Virgo Cluster Survey (GUViCS) VIII. Diffuse dust in the Virgo intra-cluster space

Abstract

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