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The feeble giant: Discovery of a large and diffuse Milky Way dwarf galaxy in the constellation of Crater

Published version
Peer-reviewed

Type

Article

Change log

Authors

Torrealba, G 
Koposov, SE 

Abstract

© 2016 The Authors Published by Oxford University Press on behalf of the Royal Astronomical Society.We announce the discovery of the Crater 2 dwarf galaxy, identified in imaging data of the VLT Survey Telescope ATLAS survey. Given its half-light radius of ~1100 pc, Crater 2 is the fourth largest satellite of the Milky Way, surpassed only by the Large Magellanic Cloud, Small Magellanic Cloud and the Sgr dwarf. With a total luminosity of MV ≈ -8, this galaxy is also one of the lowest surface brightness dwarfs. Falling under the nominal detection boundary of 30 mag arcsec-2, it compares in nebulosity to the recently discovered Tuc 2 and Tuc IV and UMa II. Crater 2 is located ~120 kpc from the Sun and appears to be aligned in 3D with the enigmatic globular cluster Crater, the pair of ultrafaint dwarfs Leo IV and Leo V and the classical dwarf Leo II. We argue that such arrangement is probably not accidental and, in fact, can be viewed as the evidence for the accretion of the Crater-Leo group.

Description

Keywords

Galaxy: halo, Galaxies: dwarf

Journal Title

Monthly Notices of the Royal Astronomical Society

Conference Name

Journal ISSN

0035-8711
1365-2966

Volume Title

459

Publisher

Oxford University Press

Rights

Publisher's own licence
Sponsorship
Science and Technology Facilities Council (ST/N004493/1)
Science and Technology Facilities Council (ST/N000927/1)