The VIRUS-P Exploration of Nearby Galaxies (VENGA): the stellar populations and assembly of NGC 2903's bulge, bar, and outer disc

Carrillo, Andreia; Jogee, Shardha; Drory, Niv; Kaplan, Kyle F.; Blanc, Guillermo; Weinzirl, Tim; Song, Mimi; Luo, Rongxin

Abstract

We study the stellar populations and assembly of the nearby spiral galaxy NGC 2903's bulge, bar, and outer disc using the VIRUS-P Exploration of Nearby Galaxies IFS survey. We observe NGC 2903 with a spatial resolution of 185 pc using the Mitchell Spectrograph's 4.25 arcsec fibres at the 2.7 Harlan J. Smith telescope. Bulge-bar-disc decomposition on the Two Micron All-Sky Survey (2MASS) K-s-band image of NGC 2903 shows that it has similar to 6 per cent, 6 per cent, and 88 per cent, of its stellar mass in the bulge, bar, and outer disc, respectively, and its bulge has a low Sersic index of similar to 0.27, suggestive of a discy bulge. We perform stellar population synthesis and find that the outer disc has 46 per cent of its mass in stars >5 Gyr, 48 per cent in stars between 1 and 5 Gyr, and <10 per cent in younger stars. Its stellar bar has 65 per cent of its mass in ages 1-5 Gyr and has metallicities similar to the outer disc, suggestive of the evolutionary picture where the bar forms from disc material. Its bulge is mainly composed of old high-metallicity stars though it also has a small fraction of young stars. We find enhanced metallicity in the spiral arms and central region, tracing areas of high star formation as seen in the H alpha map. These results are consistent with the idea that galaxies of low bulge-to-total mass ratio and low bulge Sersic index like NGC 2903 has not had a recent major merger event, but has instead grown mostly through minor mergers and secular processes.

Más información

Título según WOS: The VIRUS-P Exploration of Nearby Galaxies (VENGA): the stellar populations and assembly of NGC 2903's bulge, bar, and outer disc
Título de la Revista: MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
Volumen: 493
Número: 3
Editorial: OXFORD UNIV PRESS
Fecha de publicación: 2020
Página de inicio: 4094
Página final: 4106
DOI:

10.1093/MNRAS/STAA397

Notas: ISI