A DIRECT STELLAR METALLICITY DETERMINATION IN THE DISK OF THE MASER GALAXY NGC 4258

Journal Article · Fri Dec 20 04:00:00 EST 2013 · Astrophysical Journal Letters

DOI:https://doi.org/10.1088/2041-8205/779/2/L20· OSTI ID:22364091

Kudritzki, Rolf-Peter; Gazak, Zachary; Hosek, Jr., Matthew W.; Bresolin, Fabio ^[1]; Urbaneja, Miguel A.; Przybilla, Norbert ^[2]; Macri, Lucas ^[3]

---

1. Institute for Astronomy, University of Hawaii, 2680 Woodlawn Drive, Honolulu, HI 96822 (United States)
2. Institute for Astro- and Particle Physics, University of Innsbruck, Technikerstr. 25/8, A-6020 Innsbruck (Austria)
3. George P. and Cynthia Woods Mitchell Institute for Fundamental Physics and Astronomy, Department of Physics and Astronomy, Texas A and M University, 4242 TAMU, College Station, TX 77843-4242 (United States)

We present the first direct determination of a stellar metallicity in the spiral galaxy NGC 4258 (D = 7.6 Mpc) based on the quantitative analysis of a low-resolution (∼5 Å) Keck Low Resolution Imaging Spectrograph spectrum of a blue supergiant star located in its disk. A determination of stellar metallicity in this galaxy is important for the absolute calibration of the Cepheid period-luminosity relation as an anchor for the extragalactic distance scale and for a better characterization of its dependence as a function of abundance. We find a value 0.2 dex lower than solar metallicity at a galactocentric distance of 8.7 kpc, in agreement with recent H II region studies using the weak forbidden auroral oxygen line at 4363 Å. We determine the effective stellar temperature, gravity, luminosity, and line-of-sight extinction of the blue supergiant being studied. We show that it fits well on the flux-weighted gravity-luminosity relation, strengthening the potential of this method as a new extragalactic distance indicator.

• OSTI ID: 22364091
• Journal Information: Astrophysical Journal Letters, Journal Name: Astrophysical Journal Letters Journal Issue: 2 Vol. 779; ISSN 2041-8205
• Country of Publication: United States
• Language: English

Related Subjects

79 ASTRONOMY AND ASTROPHYSICS
ASTROPHYSICS
CALIBRATION
DISTANCE
GALAXIES
GRAVITATION
INDICATORS
LUMINOSITY
MASERS
METALLICITY
OXYGEN
POTENTIALS
RED SHIFT
RESOLUTION
SUPERGIANT STARS