Search Publications
Initial mass function biases created by binning and unresolved systems
Maíz Apellániz, Jesús
I discuss two of the possible sources of biases in the determination of the stellar initial mass function: binning and the existence of unresolved components. The first source is important for clusters with a small number of stars detected in a given mass bin, while the second is relevant for all clusters located beyond the immediate solar neighbo…
A Hubble Space Telescope/NICMOS view of the prototypical giant H ii region NGC604 in M33
Walborn, Nolan R.; Bolatto, Alberto; Barbá, Rodolfo H. +5 more
We present the first high-spatial-resolution near-infrared (NIR) imaging of NGC604, obtained with the NICMOS camera onboard the Hubble Space Telescope (HST). These NICMOS broad-band images reveal new NIR point sources, clusters, and diffuse structures. We find an excellent spatial correlation between the 8.4 GHz radio continuum and the 2.2 µ…
Detecting metal-rich intermediate-age globular clusters in NGC4570 using K-band photometry
Kotulla, Ralf; Anders, Peter; Fritze, Uta
Globular cluster systems (GCSs) of most early-type galaxies feature two peaks in their optical colour distributions. Blue-peak globular clusters (GCs) are believed to be old and metal-poor, whereas the ages, metallicities, and the origin of the red-peak GCs are still being debated. We obtained deep K-band photometry and combined it with Hubble Spa…
The formation and evolution of massive stellar clusters in IC4662
Vacca, William D.; Gilbert, Andrea M.
We present a multiwavelength study of the formation of massive stellar clusters, their emergence from cocoons of gas and dust, and their feedback on surrounding matter. Using data that span from radio to optical wavelengths, including Spitzer and Hubble Space Telescope ACS observations, we examine the population of young star clusters in the centr…
Probing young massive clusters with laser guide star adaptive optics
McCrady, Nate
We use laser guide star adaptive optics (LGS/AO) on the 10 m Keck II telescope to obtain high spatial resolution images of young massive clusters (YMCs) in NGC1569 and M82. These data probe YMC structure and the relation of the YMCs to the ambient field star population. The higher resolution of Keck LGS/AO relative to Hubble Space Telescope/NICMOS…
Stellar clusters in the nuclear regions of AGN with the Advanced Camera for Surveys
Pérez, Enrique; Schmitt, Henrique R.; Cid Fernandes, Roberto +2 more
We explore the role of star clusters in the nuclear regions of galaxies through their connection with active galactic nuclei (AGN). Nuclear star clusters (NCs) are conspicuous in the centers of most nearby galaxies, all along the Hubble sequence. These clusters are probably the faint-end distribution of the central supermassive black holes (SMBHs)…
Gas kinematics in the halo of the warm ULIRG PKS1345+12
Tadhunter, Clive N.; González Delgado, Rosa M.; Rodríguez Zaurín, Javier +1 more
We use long-slit spectra taken with the William Herschel Telescope on La Palma and high-resolution Hubble Space Telescope imaging to study the gas kinematic in the halo of the ultraluminous infrared/radio galaxy PKS1345+12 ( z=0.122). Our long-slit spectra show line splitting at the locations of massive star clusters ( 106<M_{SSC}^{Y…
Star formation in NGC5471
Pérez, Enrique; Cerviño, Miguel; Díaz, Ángeles I. +2 more
We present a study of the star formation in the giant HII region NGC5471 in the outskirts of M101. We have performed integrated photometry of the mean emission knots. Stellar population analysis with the code chorizos is compatible with the hypothesis that these regions have at least two different populations. The color–magnitude diagram of the re…
The evolution of star clusters: the resolved-star approach
Calzetti, Daniela; Pellerin, Anne; Harris, Jason +1 more
We present the first results of a new technique to detect, locate, and characterize young dissolving star clusters. Using Hubble Space Telescope/Advanced Camera for Surveys archival images of the nearby galaxy IC2574, we performed stellar PSF photometry and selected the most massive stars as our first test sample. We used a group-finding algorithm…
Properties of the ionised gas of circumnuclear star-forming regions in early-type spirals
Terlevich, Roberto; Terlevich, Elena; Díaz, Ángeles I. +1 more
A study of circumnuclear star-forming regions (CNSFRs) in several early-type spirals has been carried out in order to investigate their main properties: stellar and gas kinematics, dynamical masses, ionising stellar masses, chemical abundances and other properties of the ionised gas. Both high resolution (R∼20,000) and moderate resolution (R∼5000)…