2020A&A...640L..19J


C.D.S. - SIMBAD4 rel 1.7 - 2020.10.26CET14:53:15

2020A&A...640L..19J - Astronomy and Astrophysics, volume 640, L19-19 (2020/8-1)

Is NGC 300 a pure exponential disk galaxy?

JANG I.S., DE JONG R.S., MINCHEV I., BELL E.F., MONACHESI A., HOLWERDA B.W., BAILIN J., SMERCINA A. and D'SOUZA R.

Abstract (from CDS):

NGC 300 is a low-mass disk galaxy in the Sculptor group. In the literature, it has been identified as a pure exponential disk galaxy, as its luminosity profile can be well fit with a single exponential law over many disk scale lengths (Type I). We investigate the stellar luminosity distribution of NGC 300 using Hubble Space Telescope archive data, reaching farther and deeper than any other previous studies. Color-magnitude diagrams show a significant population of old red giant branch (RGB) stars in all fields out to R∼19kpc (32'), as well as younger populations in the inner regions. We construct the density profiles of the young, intermediate-aged, and old stellar populations, and find two clear breaks in the density profiles of the old RGB and intermediate-aged stars: one down bending (Type II) at R∼5.9kpc, and another up bending (Type III) at R∼8.3kpc. Moreover, the old RGB stars exhibit a negative radial color gradient with an upward bend at R∼8kpc, beyond which the stellar populations are uniformly old (>7Gyr) and metal poor ([Fe/H]=-1.6–0.4+0.2dex). The outer stellar component at R≳8kpc is therefore well separated from the inner disk in terms of stellar density and stellar population. While our results cast doubt on the currently established wisdom that NGC 300 is a pure exponential disk galaxy, a more detailed survey should be carried out to identify the outskirts as either a disk or a stellar halo.

Abstract Copyright: © ESO 2020

Journal keyword(s): Galaxy: halo - galaxies: individual: NGC 300 - Galaxy: structure - galaxies: stellar content - galaxies: spiral

Simbad objects: 5

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Number of rows : 5

N Identifier Otype ICRS (J2000)
RA
ICRS (J2000)
DEC
Mag U Mag B Mag V Mag R Mag I Sp type #ref
1850 - 2020
#notes
1 NGC 300 GiG 00 54 53.4460065856 -37 41 03.182962667 8.83 8.69 8.13 7.46   ~ 1328 2
2 NAME Scl Group GrG 01 00 06 -33 44.2           ~ 465 0
3 NGC 4123 AGN 12 08 11.082 +02 52 41.91   13.1       ~ 310 1
4 M 101 GiP 14 03 12.583 +54 20 55.50   8.46 7.86 7.76   ~ 2577 2
5 NGC 5833 G 15 11 53.7657838188 -72 51 33.631638162   12.3   12.3 12.0 ~ 50 0

    Equat.    Gal    SGal    Ecl

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2020.10.26-14:53:15

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