The Stellar Content and Star Formation History of the late-type spiral galaxy NGC 300 from Hubble Space Telescope observations

Abstract

We present the first WFPC2 V, I photometry for the Sculptor Group galaxy NGC 300 in four fields ranging from the centre to the outer edge. We have made the first measurement of the star formation histories in two disk fields: the oldest stars were born at similar epochs and formation activity increased but at different mean rates. The main disk stellar population is predominantly old, consisting of RGB and AGB stars, based on a synthetic colour magnitude diagram analysis. Z is found to have been more metal poor than 0.006 (or 0.33Zsolar) with no evidence for significant change in the mean Z value over time in both disk fields. In the central region, we find a dearth of bright stars with respect to the two disk fields that cannot be explained by observational effects. Taken at face value, this finding would agree with the Davidge (1998) report of suppressed star formation there during the past 1Gyr with respect to his disk fields at larger radii; but the possibility of significant central extinction affecting our finding remains. We have also determined the first distance modulus estimate based on the tip of the red giant branch method: on the Cepheid distance scale of Ferrarese et al. (2000) we find (m-M)o = 26.56+/-0.07 (+/-0.13) mag; and a similar value from the Cepheid-independent empirical method by Lee et al. (1993), both in good agreement with the Cepheid distance determined by Freedman et al. (2001). A discrepancy between this and the theoretical calibration of the red giant branch tip magnitude method remains. Finally, we report a newly detected young (up to about 10Myr) stellar association of about average size (~140pc) in one of the disk fields.

47 pages, 12 figures (the quality of Figures 1 and 6 has been degraded), Corrected minor textual errors and two reference omissions to match the version to be published in The Astronomical Journal

References in corpus (7)

• Distances and ages of NGC 6397, NGC 6752 and 47 Tuc
• Distances to Nearby Galaxies in Sculptor
• The Formation of a Disk Galaxy within a Growing Dark Halo
• Quantitative spectral analysis of early B-type supergiants in the Sculptor galaxy NGC 300
• A large Wolf-Rayet population in NGC300 uncovered by VLT-FORS2
• Discovery and quantitative spectral analysis of an Ofpe/WN9 (WN11) star in the Sculptor spiral galaxy NGC 300
• Comparing Young Stellar Populations Across Active Regions in the M31 Disk

Cited by in corpus (24)

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• The Anatomy of Star Formation in NGC 300
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• NGC 300: an extremely faint, outer stellar disk observed to 10 scale lengths
• The Araucaria Project. Near-Infrared Photometry of Cepheid Variables in the Sculptor Galaxy NGC 300
• The ACS Nearby Galaxy Survey Treasury V. Radial Star Formation History of NGC 300
• A Study of Edge-On Galaxies with the Hubble Space Telescope's Advanced Camera for Surveys. I. Initial Results
• The Abundance Gradient in the Extremely Faint Outer Disk of NGC 300
• On the stellar populations in NGC 185 and NGC 205, and the nuclear star cluster in NGC 205 from Hubble Space Telescope observations
• Thick disks and halos of spiral galaxies M 81, NGC 55 and NGC 300
• The NGC 300 Transient: An Alternative Method For Measuring Progenitor Masses
• Stellar Feedback and Resolved Stellar IFU Spectroscopy in the nearby Spiral Galaxy NGC 300
• A Council of Giants
• The Araucaria Project. An improved distance to the Sculptor spiral galaxy NGC 300 from its Cepheid variables
• Euclid preparation: XVI. Exploring the ultra low-surface brightness Universe with Euclid/VIS
• The Disk and Extraplanar Environment of NGC 247
• The Araucaria Project: The Distance to NGC 300 from the Red Giant Branch Tip using HST/ACS imaging
• Optical supernova remnants in nearby galaxies and their influence on star formation rates derived from H$\alpha$ emission
• The star-formation history of low-mass disk galaxies: a case study of NGC\,300
• UBVI Surface Photometry of the Spiral Galaxy NGC 300 in the Sculptor Group
• Optical Spectra of SNR Candidates in NGC 300
• A systematic aging method I: HII regions D118 and D119 in NGC 300
• MUSE crowded field 3D spectroscopy in NGC 300 : IV. Planetary nebula luminosity function