328 research outputs found
The K-band luminosity functions of super star clusters in luminous infrared galaxies, their slopes, and the effects of blending
Full text linkSuper star clusters (SSCs) are typically found in interacting galaxies and
trace an extreme form of star-formation. We present a K-band study of SSC
candidates in a sample of local luminous infrared galaxies (LIRGs) using two
adaptive optics instruments (VLT/NACO and Gemini/ALTAIR/NIRI). In addition to
facilitating SSC detections in obscured environments, this work introduces SSC
studies in hosts with higher star-formation rates (SFRs) than most previous
studies. We find that the luminosity functions (LFs) of the clusters are
reasonably well-fitted by a single power-law with the values of the index
\alpha ranging between 1.5 to 2.4 with an average value of \alpha ~ 1.9. This
value appears to be less steep than the average \alpha ~ 2.2 in normal spiral
galaxies. Due to the host galaxy distances involved (median ~ 70 Mpc)
blending effects have to be taken into account, and are investigated using
Monte Carlo simulations of blending effects for LFs and a photometric SSC
analysis of the well-studied Antennae system which is artificially redshifted
to distances of our sample. While blending tends to flatten LFs our analyses
show that \Delta \alpha is less than ~ 0.1 in our sample. The simulations also
show that in the luminosity range, , considered in this work the
extracted SSC luminosities are generally dominated by a single dominant star
cluster rather than several knots of SF. We present resolution- and
distance-dependent SSC surface density confusion limits and show how blending
rates and aperture sizes affect the LFs. The smallest possible apertures should
be used in crowded regions.Comment: 18 pages, 11 figures, accepted for publication in MNRA
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