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# On the Distance and Reddening of the Starburst Galaxy IC 10

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(Impact Factor: 6.28). 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.

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Available from: L. Pulone, Aug 08, 2015
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##### Article: IC10: the history of the nearest starburst galaxy through its Planetary Nebula and HII region populations
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ABSTRACT: We report the results of spectroscopic observations, obtained with the Gemini North Multi-Object Spectrograph, of 9 planetary nebulae (PNe) and 15 \hii\ regions located in the 5.5\arcmin $\times$5.5\arcmin inner region of the nearby starburst galaxy IC10. Twelve new candidate PNe have been discovered during our pre-imaging phase. Nine of them have been spectroscopically confirmed. The direct availability of the electron temperature diagnostics in several nebulae allowed an accurate determination of the metallicity map of IC10 at two epochs: the present-time from \hii regions and the old/intermediate-age from PNe. We found a non-homogeneous distribution of metals at both epochs, but similar average abundances were found for the two populations. The derived age-metallicity relation shows a little global enrichment interpreted as the loss of metals by SN winds and to differential gas outflows. Finally, we analyzed the production of oxygen --through the third dredge-up-- in the chemical abundance patterns of the PN populations belonging to several dwarf irregular galaxies. We found that the third dredge-up of oxygen is a metallicity dependent phenomenon occurring mainly for 12+$\log$(O/H)$\leq$7.7 and substantially absent in IC10 PNe. Comment: 14 pages, 4 figures, 7 tables, accepted for publication by MNRAS
Monthly Notices of the Royal Astronomical Society 05/2009; DOI:10.1111/j.1365-2966.2009.15124.x · 5.23 Impact Factor
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##### Article: On the Stellar Content of the Starburst Galaxy IC10
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ABSTRACT: We investigate the stellar content of the starburst dwarf galaxy IC10 using accurate and deep optical data collected with the Advanced Camera for Surveys and with the Wide Field Planetary Camera 2 onboard the Hubble Space Telescope. The comparison between theory and observations indicates a clear change in age distribution when moving from the center toward the external regions. Moreover, empirical calibrators and evolutionary predictions suggest the presence of a spread in heavy element abundance of the order of one-half dex. The comparison between old and intermediate-age core He-burning models with a well defined overdensity in the color-magnitude diagram indicates the presence of both intermediate-age, red clump stars and of old, red horizontal branch stars.
The Astrophysical Journal 06/2009; 699(2):L84. DOI:10.1088/0004-637X/699/2/L84 · 6.28 Impact Factor
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##### Article: Tracing the Magellanic Clouds Back in Time
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ABSTRACT: A solution is presented for the past motions of the Magellanic Clouds, the Milky Way galaxy, and M31, fitted to the measured velocities of the Clouds and M31, under some simplifying assumptions. The galaxies are modeled as isolated bodies back to redshift about 10, when their velocities relative to the general expansion of the universe were small, consistent with the gravitational instability picture for the growth of structure. Mass outside the Local Group is modeled as a third massive dynamical actor that is responsible for the angular momentum of the Clouds. A plausible solution under these assumptions requires that the circular velocity v_c of the Milky Way is in the range 200 to 230 km/s. The solution seems to be unique up to the modest variations allowed by the choices of v_c and the position of the exterior mass. In this solution the proto-Magellanic Clouds at high redshift were near the South pole of the Milky Way (in its present orientation), at physical distance about 200 kpc from the Milky Way and moving away at about 200 km/s. Comment: 21 pages, 5 figures