Browsing by Author "Larsen, S. S."

Now showing 1 - 2 of 2
  • Thumbnail Image
    Item
    The Mass of the Most Massive Star in Stellar Clusters Determined from 25 Million MASSCLEAN Monte Carlo Simulations
    (2013) Popescu, Bogdan; Hanson, M. M.; Borissova, J.; Kurtev, R.; Ivanov, V.; Larsen, S. S.; Catelan, Marcio; Minniti, D.; Lucas, P.
    Is there a maximum universal stellar mass, or might the maximum stellar mass in a cluster be tied to the mass of the associated cluster? Direct measurements of the maximum stellar mass of hundreds of young stellar clusters would help us to answer this fundamental question. However, such information does not presently exist. We are mindful that the most massive star in a stellar cluster can have a strong influence on the integrated magnitudes and colors of their host stellar cluster, especially clusters in the low-mass range. Thinking strategically, this color variation provides us with a mechanism for divulging the properties of that most massive star. We performed 25 million MASSCLEAN Monte Carlo simulations of stellar clusters in the 200-1000 M_Sun range in the U, B, and V bands. These simulations were then used to estimate the mass of the most massive star for 40 young, low-mass LMC clusters. In a similar way, the integrated colors and magnitudes in VISTA's Z, Y, J, H, and Ks bands can also be used to estimate the mass of the most massive star in VISTA-identified stellar clusters. Is the IMF for one hundred young 1000 solar mass clusters the same at the high end as ten young 10,000 solar mass clusters? Using the VISTA's clusters, we intend to answer the question, "Does the lower mass of a stellar cluster artificially steepen the high-mass IMF?"....
  • No Thumbnail Available
    Item
    Using MASSCLEAN to Describe Stellar Clusters Found in the Vista Variables in the Via Lactea (VVV) Survey
    (2014) Popescu, B.; Hanson, M. M.; Borissova, J.; Kurtev, R.; Ivanov, V. D.; Catelan, Marcio; Larsen, S. S.; Minniti, D.; Lucas, P.
    The important parameters: age, mass and distance of resolved or partially resolved stellar clusters are better accurately determined by using color-magnitude diagrams (CMD). However, when the main sequence turnoff is not available or clearly identifiable, large errors in all parameters result when using simple isochrone fitting, particularly when observations are limited to near-infrared bands. We used the MASSCLEAN package to perform 5 million Monte Carlo simulations of stochastically sampled stellar clusters in order to generate CMD templates for a variety of cluster masses and ages and which mimic the observational photometric errors. This results in the creation of tens of thousands of n-dimensional stellar density maps (templates) in numerous color planes as a function of age and mass. We use these MASSCLEAN CMD templates to refine and sharpen traditional isochrone fitting to analyze the newly discovered stellar clusters/cluster candidates from the Vista Variables in the Via Lactea (VVV) Survey. Our MASSCLEAN templates are also being used to design and optimize search algorithms for stellar clusters in broad-band surveys....