RT Journal Article
T1 Discovery of an ultra-diffuse galaxy in the pisces-perseus supercluster
A1 Martínez Delgado, David
A1 Läsker, Ronald
A1 Sharina, Margarita
A1 Toloba, Elisa
A1 Fliri, Jürgen
A1 Beaton, Rachael
A1 Valls-Gabaud, David
A1 Karachentsev, Igor D.
A1 Chonis, Taylor S.
A1 Grebel, Eva K.
A1 Forbes, Duncan A.
A1 Romanowsky, Aaron J.
A1 Gallego Laborda, J.
A1 Teuwen, Karel
A1 Gómez Flechoso, María De Los Ángeles
A1 Wang, Jie
A1 Guhathakurta, Puragra
A1 Kaisin, Serafim
A1 Ho, Nhung
AB We report the discovery of DGSAT I, an ultra-diffuse, quenched galaxy located 10fdg4 in projection from the Andromeda galaxy (M31). This low-surface brightness galaxy (μV = 24.8 mag arcsec−2), found with a small amateur telescope, appears unresolved in sub-arcsecond archival Subaru/Suprime-Cam images, and hence has been missed by optical surveys relying on resolved star counts, in spite of its relatively large effective radius (Re(V) = 12'') and proximity (15') to the well-known dwarf spheroidal galaxy And II. Its red color (V − I = 1.0), shallow Sérsic index (nV = 0.68), and the absence of detectable Hα emission are typical properties of dwarf spheroidal galaxies and suggest that it is mainly composed of old stars. Initially interpreted as an interesting case of an isolated dwarf spheroidal galaxy in the local universe, our radial velocity measurement obtained with the BTA 6 m telescope (Vh = 5450 ± 40 km s−1) shows that this system is an M31-background galaxy associated with the filament of the Pisces-Perseus supercluster. At the distance of this cluster (~78 Mpc), DGSAT I would have an Re ~ 4.7 kpc and MV ~ −16.3. Its properties resemble those of the ultra-diffuse galaxies (UDGs) recently discovered in the Coma cluster. DGSAT I is the first case of these rare UDGs found in this galaxy cluster. Unlike the UDGs associated with the Coma and Virgo clusters, DGSAT I is found in a much lower density environment, which provides a fresh constraint on the formation mechanisms for this intriguing class of galaxy.
PB Cross Mark
SN 0004-6256
YR 2016
FD 2016-04
LK https://hdl.handle.net/20.500.14352/23236
UL https://hdl.handle.net/20.500.14352/23236
LA eng
NO Ministerio de Economía y Competitividad (MINECO)
NO Russian Scientific Foundation
NO NSFC
NO German Research Foundation
DS Docta Complutense
RD 10 abr 2025