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Isochrone fitting of Galactic globular clusters - IV. NGC 6362 and NGC 6723
被引:7
|作者:
Gontcharov, George A.
[1
]
Khovritchev, Maxim Yu
[1
,2
]
Mosenkov, Aleksandr, V
[1
,3
]
Il'in, Vladimir B.
[1
,2
,4
]
Marchuk, Alexander A.
[1
,2
]
Poliakov, Denis M.
[1
,2
]
Ryutina, Olga S.
[2
]
Savchenko, Sergey S.
[1
,2
,5
]
Smirnov, Anton A.
[1
,2
]
Usachev, Pavel A.
[1
,2
,5
]
Lee, Jae-Woo
[6
]
Camacho, Conner
[3
]
Hebdon, Noah
[3
]
机构:
[1] Russian Acad Sci, Cent Pulkovo Astron Observ, Pulkovskoye Chaussee 65-1, St Petersburg 196140, Russia
[2] St Petersburg State Univ, Univ Skij Pr 28, St Petersburg 198504, Russia
[3] Brigham Young Univ, Dept Phys & Astron, N283 ESC, Provo, UT 84602 USA
[4] St Petersburg Univ Aerosp Instrumentat, Bol Morskaya Ul 67A, St Petersburg 190000, Russia
[5] Russian Acad Sci, Special Astrophys Observ, Nizhnii Arkhyz 369167, Russia
[6] Sejong Univ, Dept Phys & Astron, 209 Neungdo Ro, Seoul 05006, South Korea
基金:
俄罗斯科学基金会;
新加坡国家研究基金会;
关键词:
IIertzsprung-Russell and colour-magnitude diagrams;
globular clusters: general;
globular clusters: individual: NGC 6362;
NGC;
6723;
dust;
extinction;
stars: horizontal branch;
ISM: individual objects: Corona Australis cloud complex;
UV LEGACY SURVEY;
MULTIPLE STELLAR POPULATIONS;
HORIZONTAL-BRANCH STARS;
ACS SURVEY;
PROPER MOTION;
GAIA EDR3;
I;
PHOTOMETRY;
CATALOG;
HST;
D O I:
10.1093/mnras/stac3300
中图分类号:
P1 [天文学];
学科分类号:
0704 ;
摘要:
We present new isochrone fits to the colour-magnitude diagrams of the Galactic globular clusters NGC 6362 and NGC 6723. We utilize 22 and 26 photometric filters for NGC 6362 and NGC 6723, respectively, from the ultraviolet to mid-infrared using data sets from Hubble Space Telescope, Gala, unWISE, and other photometric sources. We use models and isochrones from the Dartmouth Stellar Evolution Database (DSED) and Bag of Stellar Tracks and Isochrones (BaSTI) for alpha-enhanced [alpha/Fe] = +0.4 and different helium abundances. The metallicities [Fe/H] = -1.04 +/- 0.07 and -1.09 +/- 0.06 are derived from the red giant branch slopes in our fitting for NGC 6362 and NGC 6723, respectively. They agree with spectroscopic estimates from the literature. We find a differential reddening up to Delta E(B - V) = 0.13 mag in the NGC 6723 field due to the adjacent Corona Australis cloud complex. We derive the following for NGC 6362 and NGC 6723, respectively: distances 7.75 +/- 0.03 +/- 0.15 (statistic and systematic error) and 8.15 +/- 0.04 +/- 0.15 kpc; ages 12.0 +/- 0.1 +/- 0.8 and 12.4 +/- 0.1 +/- 0.8 Gyr; extinctions Av = 0.19 +/- 0.04 +/- 0.06 and 0.24 +/- 0.03 +/- 0.06 mag; reddenings E(B - V) = 0.056 +/- 0.01 +/- 0.02 and 0.068 +/- 0.01 +/- 0.02 mag. DSED provides systematically lower [Fe/H] and higher reddenings than BaSTI. However, the models agree in their relative estimates: NGC 6723 is 0.44 +/- 0.04 kpc further, 0.5 +/- 0.1 Gyr older, Delta E(B - V) = 0.007 +/- 0.002 more reddened, and with 0.05 +/- 0.01 dex lower [Fe/H] than NGC 6362. The lower metallicity and greater age of NGC 6723 with respect to NGC 6362 explain their horizontal branch morphology difference. This confirms age as the second parameter for these clusters. We provide lists of the cluster members from the Gala Data Release 3.
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页码:3036 / 3054
页数:19
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