44 research outputs found
Quantifying the Origin and Distribution of Intracluster Light in a Fornax-like Cluster
Using a cosmological -body simulation, we investigate the origin and
distribution of stars in the intracluster light (ICL) of a Fornax-like cluster.
In a dark matter only simulation we identify a halo which, at , has and , and replace infalling
subhalos with models that include spheroid and disc components. As they fall
into the cluster, the stars in some of these galaxies are stripped from their
hosts, and form the ICL. We consider the separate contributions to the ICL from
stars which originate in the haloes and the discs of the galaxies. We find that
disc ICL stars are more centrally concentrated than halo ICL stars. The
majority of the disc ICL stars are associated with one initially disc-dominated
galaxy that falls to the centre of the cluster and is heavily disrupted,
producing part of the cD galaxy. At radial distances greater than 200kpc, well
beyond the stellar envelope of the cD galaxy, stars formerly from the stellar
haloes of galaxies dominate the ICL. Therefore at large distances, the ICL
population is dominated by older stars.Comment: Paper published as MNRAS , 2017, 467, 4501 This version corrects a
small typo in the authors fiel
LSST: from Science Drivers to Reference Design and Anticipated Data Products
(Abridged) We describe here the most ambitious survey currently planned in
the optical, the Large Synoptic Survey Telescope (LSST). A vast array of
science will be enabled by a single wide-deep-fast sky survey, and LSST will
have unique survey capability in the faint time domain. The LSST design is
driven by four main science themes: probing dark energy and dark matter, taking
an inventory of the Solar System, exploring the transient optical sky, and
mapping the Milky Way. LSST will be a wide-field ground-based system sited at
Cerro Pach\'{o}n in northern Chile. The telescope will have an 8.4 m (6.5 m
effective) primary mirror, a 9.6 deg field of view, and a 3.2 Gigapixel
camera. The standard observing sequence will consist of pairs of 15-second
exposures in a given field, with two such visits in each pointing in a given
night. With these repeats, the LSST system is capable of imaging about 10,000
square degrees of sky in a single filter in three nights. The typical 5
point-source depth in a single visit in will be (AB). The
project is in the construction phase and will begin regular survey operations
by 2022. The survey area will be contained within 30,000 deg with
, and will be imaged multiple times in six bands, ,
covering the wavelength range 320--1050 nm. About 90\% of the observing time
will be devoted to a deep-wide-fast survey mode which will uniformly observe a
18,000 deg region about 800 times (summed over all six bands) during the
anticipated 10 years of operations, and yield a coadded map to . The
remaining 10\% of the observing time will be allocated to projects such as a
Very Deep and Fast time domain survey. The goal is to make LSST data products,
including a relational database of about 32 trillion observations of 40 billion
objects, available to the public and scientists around the world.Comment: 57 pages, 32 color figures, version with high-resolution figures
available from https://www.lsst.org/overvie