On the Distance and Reddening of the Starburst Galaxy IC 10

The Astrophysical Journal (Impact Factor: 6.73). 12/2008; 688(2):L69. DOI: 10.1086/595551
Source: arXiv

ABSTRACT We present deep and accurate optical photometry of the Local Group starburst galaxy IC 10. The photometry is based on two sets of images collected with the Advanced Camera for Surveys and with the Wide Field Planetary Camera 2 on board the Hubble Space Telescope. We provide new estimates of the tip of the red giant branch (TRGB) magnitude, = 21.90 ± 0.03, and of the reddening, E(B − V) = 0.78 ± 0.06, using field stars in the Small Magellanic Cloud (SMC) as a reference. Adopting the SMC and two globulars, ω Cen and 47 Tuc, as references we estimate the distance modulus to IC 10: independent calibrations give weighted average distances of μ = 24.51 ± 0.08 (TRGB) and μ = 24.56 ± 0.08 (RR Lyrae). We also provide a new theoretical calibration for the TRGB luminosity, and using these predictions we find a very similar distance to IC 10 (μ ≈ 24.60 ± 0.15). These results suggest that IC 10 is a likely member of the M31 subgroup.

  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: In this paper we investigate the nature of 27 star cluster candidates, most of them projected towards the Galactic anticentre. We derive fundamental parameters for 20 confirmed clusters, among these 7 are new identifications. Four of the remaining are uncertain cases that require deeper photometry to establish their nature, and 4 are probably field fluctuations. In addition, we provide a partial census of the open clusters towards the Galactic anticentre. We also include in this study some interesting objects outside the anticentre region, in the second and third Galactic quadrants, mainly in the Perseus and Outer arms. These clusters confirm the extension of the Outer arm along the third quadrant. We also point out that the embedded cluster FSR 486, at a distance of 7.2 +/- 1.3 kpc from de Sun, is projected on the line of sight of the Local Group irregular dwarf galaxy IC 10. Thus, part of the unusual properties of IC 10 may be explained by a Galactic contamination. We point out the importance of embedded clusters in tracing the spiral structure.
    Monthly Notices of the Royal Astronomical Society 04/2013; 432(4). · 5.52 Impact Factor
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: We present positions, kinematics, and the planetary nebula luminosity function (PNLF) for 35 planetary nebulae (PNe) in the nearest starburst galaxy IC10 extending out to 3kpc from the galaxy's centre. We take advantage of the deep imaging and spectroscopic capabilities provided by the spectrograph FOCAS on the 8.2m Subaru telescope. The PN velocities were measured through the slitless-spectroscopy technique, which allows us to explore the kinematics of IC10 with high precision. Using these velocities, we conclude that there is a kinematic connection between the HI envelope located around IC10 and the galaxy's PN population. By assuming that the PNe in the central regions and in the outskirts have similar ages, our results put strong observational constraints on the past tidal interactions in the Local Group. This is so because by dating the PN central stars, we, therefore, infer the epoch of a major episode of star formation likely linked to the first encounter of the HI extended envelope with the galaxy. Our deep [OIII] images also allow us to use the PNLF to estimate a distance modulus of 24.1+/-0.25, which is in agreement with recent results in the literature based on other techniques.
    Monthly Notices of the Royal Astronomical Society 07/2012; 425(4). · 5.52 Impact Factor
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: We present MMT spectroscopic observations of HII regions in 42 low luminosity galaxies in the LVL. For 31 galaxies, we measured the temperature sensitive [O III] line at a strength of 4 sigma or greater, and thus determine direct oxygen abundances. Our results provide the first direct estimates of oxygen abundance for 19 galaxies. Oxygen abundances were compared to B-band and 4.5 micron luminosities and stellar masses in order to characterize the luminosity-metallicity (L-Z) and mass-metallicity (M-Z) relationships at low-luminosity. We present and analyze a "Combined Select" sample composed of 38 objects (drawn from our parent sample and the literature) with direct oxygen abundances and reliable distance determinations (TRGB or Ceph). Consistent with previous studies, the B-band and 4.5 micron L-Z relationships were found to be 12+log(O/H)=(6.27+/-0.21)+(-0.11+/-0.01)M_B and 12+log(O/H)=(6.10+/-0.21)+(-0.10+/-0.01)M_[4.5] (sigma=0.15 and 0.14). For this sample, we derive a M-Z relationship of 12+log(O/H)=(5.61+/-0.24)+(0.29+/-0.03)log(M*), which agrees with previous studies; however, the dispersion (sigma=0.15) is not significantly lower than that of the L-Z relationships. Because of the low dispersions in these relationships, if an accurate distance is available, the luminosity of a low-luminosity galaxy is often a better indicator of metallicity than that derived using certain strong-line methods, so significant departures from the L-Z relationships may indicate that caution is prudent in such cases. We also revisit the 70/160 micron color metallicity relationship. Additionally, we examine N/O abundance trends with respect to oxygen abundance and B-V color. We find a positive correlation between N/O ratio and B-V color for 0.05\lesssimB-V\lesssim0.75: log(N/O)=(1.18+/-0.9)x(B-V)+(-1.92+/-0.08), with a dispersion of sigma=0.14, that is in agreement with previous studies.
    The Astrophysical Journal 05/2012; 754(2). · 6.73 Impact Factor

Full-text (2 Sources)

Available from
May 21, 2014