TY - JOUR
T1 - The acs nearby galaxy survey treasury. I. the star formation history of the M81 outer disk
AU - Williams, Benjamin F.
AU - Dalcanton, Julianne J.
AU - Seth, Anil C.
AU - Weisz, Daniel
AU - Dolphin, Andrew
AU - Skillman, Evan
AU - Harris, Jason
AU - Holtzman, Jon
AU - Girardi, Léo
AU - De Jong, Roelof S.
AU - Olsen, Knut
AU - Cole, Andrew
AU - Gallart, Carme
AU - Gogarten, Stephanie M.
AU - Hidalgo, Sebastian L.
AU - Mateo, Mario
AU - Rosema, Keith
AU - Stetson, Peter B.
AU - Quinn, Thomas
PY - 2009
Y1 - 2009
N2 - The Advanced Camera for Surveys (ACS) Nearby Galaxy Survey Treasury is a large Hubble Space Telescope (HST)/ACS treasury program to obtain resolved stellar photometry for a volume-limited sample of galaxies out to 4 Mpc. As part of this program, we have obtained deep ACS imaging of a field in the outer disk of the large spiral galaxy M81. The field contains the outskirts of a spiral arm as well as an area containing no current star formation. Our imaging results in a color-magnitude diagram (CMD) reaching to mF814W = 28.8 and mF606W = 29.5, one magnitude fainter than the red clump. Through detailed modeling of the full CMD, we quantify the age and metallicity distribution of the stellar populations contained in the field. The mean metallicity in the field is -1 < [M/H] < 0 and only a small fraction of stars have ages ≲ 1 Gyr. The results show that most of the stars in this outer disk field were formed by z 1 and that the arm structure at this radius has a lifetime of ≳ 100 Myr. We discuss the measured evolution of the M81 disk in the context of surveys of high redshift disk galaxies and deep stellar photometry of other nearby galaxies. All of these indicate that massive spiral disks are mostly formed by z 1 and that they have experienced rapid metal enrichment.
AB - The Advanced Camera for Surveys (ACS) Nearby Galaxy Survey Treasury is a large Hubble Space Telescope (HST)/ACS treasury program to obtain resolved stellar photometry for a volume-limited sample of galaxies out to 4 Mpc. As part of this program, we have obtained deep ACS imaging of a field in the outer disk of the large spiral galaxy M81. The field contains the outskirts of a spiral arm as well as an area containing no current star formation. Our imaging results in a color-magnitude diagram (CMD) reaching to mF814W = 28.8 and mF606W = 29.5, one magnitude fainter than the red clump. Through detailed modeling of the full CMD, we quantify the age and metallicity distribution of the stellar populations contained in the field. The mean metallicity in the field is -1 < [M/H] < 0 and only a small fraction of stars have ages ≲ 1 Gyr. The results show that most of the stars in this outer disk field were formed by z 1 and that the arm structure at this radius has a lifetime of ≳ 100 Myr. We discuss the measured evolution of the M81 disk in the context of surveys of high redshift disk galaxies and deep stellar photometry of other nearby galaxies. All of these indicate that massive spiral disks are mostly formed by z 1 and that they have experienced rapid metal enrichment.
KW - Galaxies: evolution
KW - Galaxies: individual (M81)
KW - Galaxies: spiral
KW - Galaxies: stellar content
UR - https://www.scopus.com/pages/publications/64849092859
UR - https://www.scopus.com/inward/citedby.url?scp=64849092859&partnerID=8YFLogxK
U2 - 10.1088/0004-6256/137/1/419
DO - 10.1088/0004-6256/137/1/419
M3 - Article
AN - SCOPUS:64849092859
SN - 0004-6256
VL - 137
SP - 419
EP - 430
JO - Astronomical Journal
JF - Astronomical Journal
IS - 1
ER -