Stellar Systems Group

Birth and Internal Structure of the Stellar Clusters

• Study of the modes of Star Formation To make a near-IR survey of different active cluster forming regions to quantify the influence of local environment (massive associations, HII regions) on the modes of formation (clustered, distributed) of newly formed populations. We will test whether the local environment affects star formation efficiency, star formation rate and the relative percentages of cluster vs distributed populations. Observation, data reduction and analysis of a sample of around 30 embedded clusters.
• Internal Structure. Determine the internal structure of a significant sample of young embedded clusters and analyze how this property varies with the local environment and how it evolves with age.
• Gas, Dust and Stars in Clusters. Compare, when possible, the structure of clusters with that of the surrounding gas and dust envelopes. Construct dust extinction maps in the star-forming regions using color excess of background stars.
  Determine the current values for the star formation efficiency.
• Embedded Clusters in the Gould Belt. Analyze the distribution of embedded clusters in the Gould Belt.
• Star Formation at Galactic Scale. Dust, gas, stars and stellar clusters in M33, compare the different spatial distributions at galactic scale.

Massive Stars in the Milky Way

• Database. Create the largest possible spectral database for visually observable Galactic O stars using high-quality, high-S/N, uniform data.
• Spectral Morphology. Reanalyze the fundamental spectral morphology for O stars.
• Multiplicity. Analyze the multiplicity of massive stars.
• Galactic Extinction. Obtain a new Galactic extinction law and analyze its relationship with the DIBs .
• Spatial Distribution. Study of the spatial distribution of massive stars and dust within 3 kpc of the Sun.
• Massive- star IMF. Derive the massive-star IMF in the solar neighborhood for both the field and some clusters.

PMS Stars in Clusters

• Determination of the PMS population for a larger sample of young clusters in optical and NIR bands.
• Mass Function and Age structure of the PMS sequences in the different clusters. Variations with Post-Main Sequence age and model dependencies.
• Determination of a complete and precise IMF combining data for all our sample of clusters.
• Derivation of Constraints to the Physical Inputs in PMS evolutionary models.

The Nuclear Star Cluster of the Milky Way

• Improve current models for cluster with particular emphasis on size and mass of the cluster.
• Search for young, massive stars in the cluster at projected distances between 0.5 and 5 pc from the central massive black hole, Sagittarius A*.
• Accurately constrain the extinction law toward the NSC and create an extinction map with resolution of ~5 arcseconds.
• Study the mid-infrared emission from stars and ISM in the NSC with VISIR/VLT and Canaricam/GTC.
• Improve stellar proper motion measurements in the central parsec of the Galaxy and use these measurements to determine the mass and kinematic structure of the cluster.

Methodology and tools

• Update CHORIZOS and implement the calculation of distances to individual stars and star clusters.
• Development of tools to perform a systematic search of kinematic stellar systems as moving groups, open clusters, associations and tidal streams, using the database of the astrometric catalogue CdC-SF (Vicente et al. 2010), being the final aim the application to the GAIA catalogue.
• Comparison of new algorithms for generating fractal clouds based on different physical principles.
• Optical distortion of NACO S27. Determine the optical distortion solution for the S27 camera of NACO/VLT to submilliarcsecond precision.