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HOROLOGIUM II: A SECOND ULTRA-FAINT MILKY WAY SATELLITE IN THE HOROLOGIUM CONSTELLATION

Kim, Dongwon; Jerjen, Helmut

Description

We report the discovery of a new ultra-faint Milky Way satellite candidate, Horologium II (Hor II), detected in the Dark Energy Survey Y1A1 public data. Hor II features a half-light radius of r<inf>h</inf> = 47 ±10 pc and a total luminosity of M<inf>v</inf>=- 2.6+0.3<inf>0.2</inf> that place it in the realm of ultra-faint dwarf galaxies on the sizeluminosity plane. The stellar population of the new satellite is consistent with an old (∼13.5 Gyr) and metal-poor ([Fe/H] ∼ -2.1) isochrone at a...[Show more]

dc.contributor.authorKim, Dongwon
dc.contributor.authorJerjen, Helmut
dc.date.accessioned2016-06-14T23:19:05Z
dc.identifier.issn2041-8205
dc.identifier.urihttp://hdl.handle.net/1885/102741
dc.description.abstractWe report the discovery of a new ultra-faint Milky Way satellite candidate, Horologium II (Hor II), detected in the Dark Energy Survey Y1A1 public data. Hor II features a half-light radius of r<inf>h</inf> = 47 ±10 pc and a total luminosity of M<inf>v</inf>=- 2.6+0.3<inf>0.2</inf> that place it in the realm of ultra-faint dwarf galaxies on the sizeluminosity plane. The stellar population of the new satellite is consistent with an old (∼13.5 Gyr) and metal-poor ([Fe/H] ∼ -2.1) isochrone at a distance modulus of (m - M) = 19.46 ±0.20, or a heliocentric distance of 78 ± 8 kpc, in the colormagnitude diagram. Hor II has a distance similar to the Sculptor dwarf spheroidal galaxy (∼82 kpc) and the recently reported ultra-faint satellites Eridanus III (87 ± 8 kpc) and Horologium I (79 ± 8 kpc). All four satellites are well aligned on the sky, which suggests a possible common origin. As Sculptor is moving on a retrograde orbit within the Vast Polar Structure when compared to the other classical MW satellite galaxies including the Magellanic Clouds, this hypothesis can be tested once proper motion measurements become available.
dc.publisherInstitute of Physics Publishing Ltd.
dc.rightsAuthor/s retain copyright
dc.sourceAstrophysical Journal Letters
dc.titleHOROLOGIUM II: A SECOND ULTRA-FAINT MILKY WAY SATELLITE IN THE HOROLOGIUM CONSTELLATION
dc.typeJournal article
local.description.notesImported from ARIES
local.identifier.citationvolume808
dc.date.issued2015
local.identifier.absfor020100 - ASTRONOMICAL AND SPACE SCIENCES
local.identifier.ariespublicationa383154xPUB3212
local.type.statusPublished Version
local.contributor.affiliationKim, Dongwon, College of Physical and Mathematical Sciences, ANU
local.contributor.affiliationJerjen, Helmut, College of Physical and Mathematical Sciences, ANU
local.bibliographicCitation.issue2
local.identifier.doi10.1088/2041-8205/808/2/L39
local.identifier.absseo970102 - Expanding Knowledge in the Physical Sciences
dc.date.updated2016-06-14T08:32:15Z
local.identifier.scopusID2-s2.0-84938680521
dcterms.accessRightsOpen Access
CollectionsANU Research Publications

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