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Perseus I: a distant satellite dwarf galaxy of Andromeda

Martin, N.F.; Schlafly, E.F.; Slater, C.T.; Bernard, E.J.; Rix, H.-W.; Bell, E.F.; Ferguson, A.M.N.; Finkbeiner, D.P.; Laevens, B.P.M.; Burgett, W.S.; Chambers, K.C.; Draper, P.W.; Hodapp, K.W.; Kaiser, N.; Kudritzki, R.-P.; Magnier, E.A.; Metcalfe, N.; Morgan, J.S.; Price, P.A.; Tonry, J.L.; Wainscoat, R.J.; Waters, C.

Perseus I: a distant satellite dwarf galaxy of Andromeda Thumbnail


N.F. Martin

E.F. Schlafly

C.T. Slater

E.J. Bernard

H.-W. Rix

E.F. Bell

A.M.N. Ferguson

D.P. Finkbeiner

B.P.M. Laevens

W.S. Burgett

K.C. Chambers

K.W. Hodapp

N. Kaiser

R.-P. Kudritzki

E.A. Magnier

J.S. Morgan

P.A. Price

J.L. Tonry

R.J. Wainscoat

C. Waters


We present the discovery of a new dwarf galaxy, Perseus I/Andromeda XXXIII, found in the vicinity of Andromeda (M31) in stacked imaging data from the Pan-STARRS1 3π survey. Located 27fdg9 away from M31, Perseus I has a heliocentric distance of 785 ± 65 kpc, compatible with it being a satellite of M31 at $374^{+14}_{-10}{\rm \,kpc}$ from its host. The properties of Perseus I are typical for a reasonably bright dwarf galaxy (MV = –10.3 ± 0.7), with an exponential half-light radius of rh = 1.7 ± 0.4 arcmin or $r_h = 400^{+105}_{-85}{\rm \,pc}$ at this distance, and a moderate ellipticity ($\epsilon = 0.43^{+0.15}_{-0.17}$). The late discovery of Perseus I is due to its fairly low surface brightness ($\mu _0=25.7^{+1.0}_{-0.9}$ mag arcsec–2), and to the previous lack of deep, high quality photometric data in this region. If confirmed to be a companion of M31, the location of Perseus I, far east from its host, could place interesting constraints on the bulk motion of the satellite system of M31.


Martin, N., Schlafly, E., Slater, C., Bernard, E., Rix, H., Bell, E., …Waters, C. (2013). Perseus I: a distant satellite dwarf galaxy of Andromeda. Astrophysical Journal Letters, 779(1), Article L10.

Journal Article Type Article
Publication Date Dec 10, 2013
Deposit Date Apr 3, 2014
Publicly Available Date Jun 30, 2014
Journal Astrophysical Journal Letters
Print ISSN 2041-8205
Electronic ISSN 2041-8213
Publisher American Astronomical Society
Peer Reviewed Peer Reviewed
Volume 779
Issue 1
Article Number L10
Keywords Galaxies: individual (Perseus I, Andromeda XXXIII), Local Group.


Published Journal Article (391 Kb)

Copyright Statement
© 2013. The American Astronomical Society. All rights reserved.

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