2MASS photometry and age estimation of the globular clusters in the outer halo of M31

Ma, Jun

doi:10.1088/1674-4527/12/2/001

Cited by 7 publications

(11 citation statements)

References 66 publications

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“…M31 is the ideal Local Group galaxy to study globular clusters, for it contains more globulars than all other Local Group galaxies combined (Battistini et al 1987;Racine 1991;Harris 1991;Fusi Pecci et al 1993). The globular cluster system of M31 has been extensively studied over many decades (see Ma 2012, for a recent review of the subject). In the following we focus on clusters located in the outskirts of this galaxy, because they are useful probes of the substructures expected to form in the outer region of the host galaxy (Ma 2012), as predicted by the popular ΛCDM model for galaxy formation.…”

Section: Clusters Of M31mentioning

confidence: 99%

“…The globular cluster system of M31 has been extensively studied over many decades (see Ma 2012, for a recent review of the subject). In the following we focus on clusters located in the outskirts of this galaxy, because they are useful probes of the substructures expected to form in the outer region of the host galaxy (Ma 2012), as predicted by the popular ΛCDM model for galaxy formation. This model predicts that these substructures continue to grow in time, from the accretion and the disruption of companions satellite.…”

Section: Clusters Of M31mentioning

confidence: 99%

“…The sample of M31 halo globular clusters is taken from Mackey et al (2006Mackey et al ( , 2007, who evaluated the metallicities (−2.14 < [Fe/H] < −0.70), distance modulus and reddening from their CMDs, using deep images obtained with ACS/HST. The cluster ages have been determined by Ma (2012), by comparing the integrated photometry with the SSP models by Bruzual & Charlot 7 7.5 8 8.5 9 9.5 10 −1 0 1 2 3 4 5 log t [V−K] log t<8.00 8.00<log t=9.00 9.00<log t=9.50 9.50<log t=10.00 log t>10.00 Z=0.004 Z=0.008 Z=0.02 7 7.5 8 8.5 9 9.5 10 −1 0 1 2 3 4 5 log t [V−K] log t<8.00 8.00<log t=9.00 9.00<log t=9.50 9.50<log t=10.00 log t>10.00 Z=0.0001 Z=0.0004 Figure 22. Upper panel: theoretical [V − Ks] colours of our SSPs, with (solid lines) and without (dashed lines) the contribution of circumstellar dust shell around AGB stars, as a function of age (from 0.01 to 15 Gyr, with t in yr).…”

Section: Clusters Of M31mentioning

confidence: 99%

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The role of dust in models of population synthesis

Cassarà¹,

Piovan²,

Weiß³

et al. 2013

Monthly Notices of the Royal Astronomical Society

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We have employed state-of-the-art evolutionary models of low and intermediatemass AGB stars, and included the effect of circumstellar dust shells on the spectral energy distribution (SED) of AGB stars, to revise the Padua library of isochrones (Bertelli et al. 1994) that covers an extended range of ages and initial chemical compositions. The major revision involves the thermally pulsing AGB phase, that is now taken from fully evolutionary calculations by Weiss & Ferguson (2009). Two libraries of about 600 AGB dust-enshrouded SEDs each, have also been calculated, one for oxygen-rich M-stars and one for carbon-rich C-stars. Each library accounts for different values of input parameters like the optical depth τ , dust composition, and temperature of the inner boundary of the dust shell. These libraries of dusty AGB spectra have been implemented into a large composite library of theoretical stellar spectra, to cover all regions of the Hertzsprung-Russell Diagram (HRD) crossed by the isochrones.With the aid of the above isochrones and libraries of stellar SEDs, we have calculated the spectro-photometric properties (SEDs, magnitudes, and colours) of singlegeneration stellar populations (SSPs) for six metallicities, more than fifty ages (from ∼3 Myr to 15 Gyr), and nine choices of the Initial Mass Function. The new isochrones and SSPs have been compared to the colour-magnitude diagrams (CMDs) of field populations in the LMC and SMC, with particular emphasis on AGB stars, and the integrated colours of star clusters in the same galaxies, using data from the SAGE (Surveying the Agents of Galaxy Evolution) catalogues. We have also examined the integrated colours of a small sample of star clusters located in the outskirts of M31. The agreement between theory and observations is generally good. In particular, the new SSPs reproduce the red tails of the AGB star distribution in the CMDs of field stars in the Magellanic Clouds. Some discrepancies still exist and need to be investigated further.

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Section: Clusters Of M31mentioning

confidence: 99%

Section: Clusters Of M31mentioning

confidence: 99%

Section: Clusters Of M31mentioning

confidence: 99%

See 1 more Smart Citation

The role of dust in models of population synthesis

Cassarà¹,

Piovan²,

Weiß³

et al. 2013

Monthly Notices of the Royal Astronomical Society

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“…We combined the photometry results of JHK s bands newly derived here with those derived by Ma (2012b) for 10 GCs in the M31 halo to construct a more comprehensive sample of 923 clusters in M31 to discuss the properties for them. The reddening values for the 10 GCs were derived from Ma (2012b), while the metallicities from Caldwell et al (2011) and Kang et al (2012) were used for them, respectively.…”

Section: Discussionmentioning

confidence: 99%

“…In addition, we found that some clusters (B196D, B257D, B318, B368, B453, B475, G099, KHM31-85, M056, M068, M088, M089, SK166B, V031) have one or more nearby bright objects in the images from LGS or from Wide Field Planetary Camera on Hubble Space Telescope, indicating that they are "adhered" in 2MASS images because of the poor resolution. Ma (2012b) presented JHK s photometry, ages, and masses for 10 newly-discovered halo GCs in M31. So, we will not re-estimated JHK s magnitudes for these GCs.…”

Section: Introductionmentioning

confidence: 99%

New 2mass Near-Infrared Photometry for Globular Clusters in M31

Wang

et al. 2014

Self Cite

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We present 2MASS JHK s photometry for 913 star clusters and candidates in the field of M31, which are selected from the latest Revised Bologna Catalog of M31 globular clusters (GCs) and candidates. The photometric measurements in this paper supplement this catalog, and provide a most comprehensive and homogeneous photometric catalog for M31 GCs in the JHK s bandpasses. In general, our photometry is consistent with previous measurements. The globular cluster luminosity function (GCLF) peaks for the confirmed GCs derived by fitting a t 5 distribution using maximum likelihood method are: J 0 = 15.348 +0.206 −0.208 , H 0 = 14.703 +0.176 −0.180 , and K s0 = 14.534 +0.142 −0.146 , all of which agree well with previous studies. The GCLFs are different between metalrich (MR) and metal-poor (MP), inner and outer subpopulations, as that MP clusters are fainter than their MR counterparts, and the inner clusters are brighter than the outer ones, which confirm previous results. The NIR colors of the GC candidates are on average redder than those of the confirmed GCs, which lead to an obscure bimodal distribution of the color indices. The relation of (V − K s ) 0 and metallicity shows a notable departure from linearity, with a shallower slope towards the redder end. The color-magnitude diagram (CMD) and colorcolor diagram show that many GC candidates are located out of the evolutionary tracks, suggesting that some of them may be false M31 GC candidates. The CMD also shows that the initial mass function of M31 GCs covers a large range, and the majority of the clusters have initial masses between 10 3 and 10 6 M ⊙ .

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Ages and chemical compositions of massive clusters in NGC147 and M31

Шарина

Shimansky

2015

Proc. IAU

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We present estimates of ages, [Fe/H], helium content (Y) and abundances of C, N, Mg, Ca, and several other elements for the following globular clusters (GCs): GC7 in NGC147, and Mayall II, Mackey 1 and Mackey 6 in M31. Medium-resolution integrated-light spectra of the GCs were conducted with the 6m telescope. To derive the ages and abundances for the GCs we carried out their population synthesis using model stellar atmospheres, the Padova YZVAR isochrones and the Chabrier mass function. We compare the results with the corresponding data obtained using the same method for several massive Galactic GCs. We show that the differences in the light-element abundances between GCs with similar ages and metallicities may reach 0.5-0.6 dex. The corresponding differences for other elements are usually 2-3 times smaller. We suggest that at least partially the detected differences may be due to light-element abundance variations in the atmospheres of high-luminosity red giant branch stars as a consequence of the transportation of the produced elements to the surface layers.

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2MASS photometry and age estimation of the globular clusters in the outer halo of M31

Cited by 7 publications

References 66 publications

The role of dust in models of population synthesis

The role of dust in models of population synthesis

New 2mass Near-Infrared Photometry for Globular Clusters in M31

Ages and chemical compositions of massive clusters in NGC147 and M31

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