The Distribution and Ages of Star Clusters in the Small Magellanic Cloud: Constraints on the Interaction History of the Magellanic Clouds

Bitsakis, T.; González-Lópezlira, Rosa A.; Bonfini, P.; Bruzual, G.; Maravelias, G.; Zaritsky, Dennis; Charlot, S.; Ramirez-Siordia, V. H.

doi:10.3847/1538-4357/aaa244

Cited by 25 publications

(42 citation statements)

References 43 publications

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“…These populations follow the distribution of star formation in the SMC, which is predominantly along the bar of the SMC, and extend to the LMC through the MB. This is depicted from the star cluster (especially for those with ages <100 Myr) distribution of the SMC (Bitsakis et al 2018). A further detailed analysis of identified massive star populations will be presented in our following papers.…”

Section: Multiwavelength Time-series Datamentioning

confidence: 97%

Evolved massive stars at low-metallicity

Yang

Bonanos

Jiang

et al. 2019

A&A

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We present a clean, magnitude-limited (IRAC1 or WISE1 ≤ 15.0 mag) multiwavelength source catalog for the Small Magellanic Cloud (SMC) with 45 466 targets in total, with the purpose of building an anchor for future studies, especially for the massive star populations at low-metallicity. The catalog contains data in 50 different bands including 21 optical and 29 infrared bands, retrieved from SEIP, VMC, IRSF, AKARI, HERITAGE, Gaia, SkyMapper, NSC, Massey (2002, ApJS, 141, 81), and GALEX, ranging from the ultraviolet to the far-infrared. Additionally, radial velocities and spectral classifications were collected from the literature, and infrared and optical variability statistics were retrieved from WISE, SAGE-Var, VMC, IRSF, Gaia, NSC, and OGLE. The catalog was essentially built upon a 1″ crossmatching and a 3″ deblending between the Spitzer Enhanced Imaging Products (SEIP) source list and Gaia Data Release 2 (DR2) photometric data. Further constraints on the proper motions and parallaxes from Gaia DR2 allowed us to remove the foreground contamination. We estimate that about 99.5% of the targets in our catalog are most likely genuine members of the SMC. Using the evolutionary tracks and synthetic photometry from MESA Isochrones & Stellar Tracks and the theoretical J − KS color cuts, we identified 1405 red supergiant (RSG), 217 yellow supergiant, and 1369 blue supergiant candidates in the SMC in five different color-magnitude diagrams (CMDs), where attention should also be paid to the incompleteness of our sample. We ranked the candidates based on the intersection of different CMDs. A comparison between the models and observational data shows that the lower limit of initial mass for the RSG population may be as low as 7 or even 6 M⊙ and that the RSG is well separated from the asymptotic giant branch (AGB) population even at faint magnitude, making RSGs a unique population connecting the evolved massive and intermediate stars, since stars with initial mass around 6 to 8 M⊙ are thought to go through a second dredge-up to become AGB stars. We encourage the interested reader to further exploit the potential of our catalog.

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Section: Multiwavelength Time-series Datamentioning

confidence: 97%

Evolved massive stars at low-metallicity

Yang

Bonanos

Jiang

et al. 2019

A&A

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“…multiple peaks of star formation in the past few hundred million years (Yoshizawa & Noguchi 2003;Harris & Zaritsky 2009;Indu & Subramaniam 2011), may have a different effect on the two galaxies. For example, Bitsakis et al (2017Bitsakis et al ( , 2018 studied the distribution and ages of star clusters in the LMC and SMC and found that the star clusters at the central regions were younger in the SMC than in the LMC. Therefore, if SMC RSGs are younger, then perhaps this may indicate that they have lost less mass, assuming the MLR is the same, so less material is around them.…”

Section: Comparison Between the Lmc And Smcmentioning

confidence: 99%

Evolved massive stars at low-metallicity

Yang

Bonanos

Jiang

et al. 2021

A&A

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We present a clean, magnitude-limited (IRAC1 or WISE1 ≤ 15.0 mag) multiwavelength source catalog for the Large Magellanic Cloud (LMC). The catalog was built by crossmatching (1″) and deblending (3″) between the source list of Spitzer Enhanced Imaging Products and Gaia Data Release 2, with strict constraints on the Gaia astrometric solution in order to remove the foreground contamination. It is estimated that about 99.5% of the targets in our catalog are most likely genuine members of the LMC. The catalog contains 197 004 targets in 52 different bands, including two ultraviolet, 21 optical, and 29 infrared bands. Additional information about radial velocities and spectral and photometric classifications were collected from the literature. We compare our sample with the sample from Gaia Collaboration (2018, A&A, 616, A12), indicating that the bright end of our sample is mostly comprised of blue helium-burning stars (BHeBs) and red HeBs with inevitable contamination of main sequence stars at the blue end. After applying modified magnitude and color cuts based on previous studies, we identified and ranked 2974 red supergiant, 508 yellow supergiant, and 4786 blue supergiant candidates in the LMC in six color-magnitude diagrams (CMDs). The comparison between the CMDs from the two catalogs of the LMC and Small Magellanic Cloud (SMC) indicates that the most distinct difference appears at the bright red end of the optical and near-infrared CMDs, where the cool evolved stars (e.g., red supergiant stars (RSGs), asymptotic giant branch stars, and red giant stars) are located, which is likely due to the effect of metallicity and star formation history. A further quantitative comparison of colors of massive star candidates in equal absolute magnitude bins suggests that there is essentially no difference for the BSG candidates, but a large discrepancy for the RSG candidates since LMC targets are redder than the SMC ones, which may be due to the combined effect of metallicity on both spectral type and mass-loss rate as well as the age effect. The effective temperatures (Teff) of massive star populations are also derived from reddening-free color of (J − KS)0. The Teff ranges are 3500 < Teff < 5000 K for an RSG population, 5000 < Teff < 8000 K for a YSG population, and Teff > 8000 K for a BSG population, with larger uncertainties toward the hotter stars.

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“…The SMASH dataset provides the opportunity to re-derive a star cluster catalog for the MCs using uniform data and cluster detection techniques which should be more spatially complete than previous searches. This new effort aims to overcome shortcomings of recent algorithmic detection efforts (see Bitsakis et al 2017Bitsakis et al , 2018Piatti 2018a,b) by conducting a well-characterized crowdsourced visual search of the SMASH imaging. This technique continues the long tradition of visual cluster identification across the Local Group, and builds on the legacy of crowdsourced cluster identification in the Andromeda Galaxy (Johnson et al 2015), which demonstrated the capability and robustness of this methodology.…”

Section: Star Cluster Searchmentioning

confidence: 99%

SMASH: Survey of the MAgellanic Stellar History

Nidever

Olsen

Walker

et al. 2017

Self Cite

126

103

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The Large and Small Magellanic Clouds are unique local laboratories for studying the formation and evolution of small galaxies in exquisite detail. The Survey of the MAgellanic Stellar History (SMASH) is an NOAO community Dark Energy Camera (DECam) survey of the Clouds mapping 480 deg 2 (distributed over ∼2400 square degrees at ∼20% filling factor) to ∼24thmag in ugriz. The primary goals of SMASH are to identify low surface brightness stellar populations associated with the stellar halos and tidal debris of the Clouds, and to derive spatially resolved star formation histories. Here, we present a summary of the survey, its data reduction, and a description of the first public Data Release (DR1). The SMASH DECam data have been reduced with a combination of the NOAO Community Pipeline, the PHOTRED automated point-spread-function photometry pipeline, and custom calibration software. The astrometric precision is ∼15 mas and the accuracy is ∼2 mas with respect to the Gaia reference frame. The photometric precision is ∼0.5%-0.7% in griz and ∼1% in u with a calibration accuracy of ∼1.3% in all bands. The median 5σ point source depths in ugriz are 23.9, 24.8, 24.5, 24.2, and 23.5 mag. The SMASH data have already been used to discover the Hydra II Milky Way satellite, the SMASH 1 old globular cluster likely associated with the LMC, and extended stellar populations around the LMC out to R∼18.4 kpc. SMASH DR1 contains measurements of ∼100 million objects distributed in 61 fields. A prototype version of the NOAO Data Lab provides data access and exploration tools.

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The Distribution and Ages of Star Clusters in the Small Magellanic Cloud: Constraints on the Interaction History of the Magellanic Clouds

Cited by 25 publications

References 43 publications

Evolved massive stars at low-metallicity

Evolved massive stars at low-metallicity

Evolved massive stars at low-metallicity

SMASH: Survey of the MAgellanic Stellar History

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