The Analysis of Star Cluster Family in The Northern Part of
Carina Nebula
R. P. Ayu1, R. Priyatikanto1,2, M. I. Arifyanto1, R. W.
Romadhonia1, M. Hilmi1,
I. K. Fitriana1, H. R. T. Wulandari1
1 Department of Astronomy, Institut Teknologi Bandung
2 Space Science Center, National Institute of Aeronautics and
Space Indonesia
Abstract
We studied a cluster family in the northern part of Carina
Nebula (NGC 3372) which is a group
of clusters nearby NGC 3324 (Tr 15, NGC 3293, Loden 165, Loden
153 and IC 2581). The age
of these clusters are about 10 Myrs or younger, and some of them
are embedded within
clouds. Age similarity and closeness between these clusters may
indicate that they have
primordial binarity. Previous studies have mentioned the
probable binarity between cluster
NGC 3324 Tr 15 and NGC 3293 IC 2581 (Turner et al. 1980) but
recently de la Fuente
Marcos & de la Fuente Marcos (2009) argued the binarity of
NGC 3324 NGC 3293. We used
data from UCAC4 to determine the clusters membership and the
near infrared CMDs of each
clusters. We analyze the spatial density and elongation as a
function of radius for each cluster
and found another possible interaction between NGC 3293 Loden
153. However the shape
distortion of NGC 3324 cannot be evaluated because of the
inhomogenity in the coverage of
UCAC4 in the east part of NGC 3324.
Cosmic Dynamics with Quintessence as Dark Energy Model
Bachelor Thesis of Miftahul Hilmi
Abstract
Various models of dark energy have been proposed to explain
cosmic acceleration.
Quintessence is one of dark energy models in the form of a
scalar field. With its Lagrangian
that takes a form of kinetic component and its potential, it is
possible for this scalar field to
drive late-time cosmic acceleration.
In this work, cosmic dynamics with the presence of a
quintessence has been derived.
I will start by reviewing about phase plane analysis of a model
with exponential potential.
After that, cosmic dynamics for the case of non-potential
exponential is derived. In the case
of non-exponential potential, there will be a tracker solution
that attract other trajectories to
a common evolutionary path.
In addition, I will discuss about reconstruction of quintessence
from observations,
starting from reconstruction of the field potential, to the
evolution of its equation of state. I
will also review about statefinder parameters (Sahni et al.,
2003) that can be used to
distinguish any dark energy models from cosmological constant.
Finally, (, ) plane as a
classification of quintessence models is discussed.
Keywords: quintessence, exponential potential, tracker solution,
evolution of equation of
state
