Characterisation of compact stellar systems in the Coma cluster of galaxies
Loading...
Date
2021
Authors
Journal Title
Journal ISSN
Volume Title
Publisher
Abstract
We present the Coma Cluster Core PrOject (C3PO), a deep, high resolution and contiguous mosaic survey of the inner ⇡ 150 square
arcminutes of the core of the Coma Cluster. The region was tiled
by 21 HST/WFC3 pointings and was observed in F336W from the
UVIS channel, and F160W from the IR channel. Using this data, and
combining this with archival data in F475W and F814W taken previously in programs led by some of our team members, we study the
compact stellar systems of said cluster. We separate those systems
from background galaxies and foreground stars guided by a nearUV/visible/near-IR colour-colour diagram, obtaining more than 9000
objects. From our selection, we study the globular cluster luminosity function in our available bands, finding values of the turn-over
magnitude of 26.2 mag for F814W, 27.3 mag for F475W, and 25.8 in
F160W. We recover the blue and red GC populations found by Peng
et al. [138], finding similar relative abundances and spatial distribution. We do not recover the colour distribution found by Madrid et al.
[119] because their extremely red objects are not present in our data,
most likely due to the inclusion of the u band. For the first time with
such diagnostic power, age and metallicity are derived for distant
GCs. 60% of our GC sample falls inside the range of our SSP models,
finding an age-metallicity relation that does not correlate with any
single colour, but is rather dependant on pairs of colours. The age
and metallicity also do not correlate strongly with spatial distribution or environment. Colour-colour relations with visible (gi) colours
show differences with varying environment, which may indicate differences in star formation history and chemical enrichment history.
The dataset also contains a large number of UCDs, and the method
can be easily expanded to also find NSCs.
Description
Tesis (Doctor en Astrofísica)--Pontificia Universidad Católica de Chile, 2021