26 research outputs found
Library Reader Issue 02: Source Of Clarification
Library resource awareness poster covering the difference between primary, secondary, and tertiary sources, along with UNE Library resources which carry each.https://dune.une.edu/libraryreader/1001/thumbnail.jp
Ultra diffuse galaxies in the Hydra I cluster from the LEWIS Project: Phase-Space distribution and globular cluster richness
Although ultra diffuse galaxies (UDGs) are found in large numbers in clusters
of galaxies, the role of the cluster environment in shaping their low surface
brightness and large sizes is still uncertain. Here we examine a sample of UDGs
in the Hydra I cluster (D = 51 Mpc) with new radial velocities obtained as part
of the LEWIS (Looking into the faintest with MUSE) project using VLT/MUSE data.
Using a phase-space, or infall diagnostic, diagram we compare the UDGs to other
known galaxies in the Hydra I cluster and to UDGs in other clusters. The UDGs,
along with the bulk of regular Hydra I galaxies, have low relative velocities
and are located near the cluster core, and thus consistent with very early
infall into the cluster. Combining with literature data, we do not find the
expected trend of GC-rich UDGs associated with earlier infall times. This
result suggests that quenching mechanisms other than cluster infall should be
further considered, e.g. quenching by strong feedback or in cosmic sheets and
filaments. Tidal stripping of GCs in the cluster environment also warrants
further modelling.Comment: 6 pages, 2 figures, MNRAS, 525, 9
Looking into the faintEst WIth MUSE (LEWIS): on the nature of ultra-diffuse galaxies in the Hydra-I cluster.I. Project description and preliminary results
Looking into the faintEst WIth MUSE (LEWIS) is an ESO large observing
programme aimed at obtaining the first homogeneous integral-field spectroscopic
survey of 30 extremely low-surface brightness (LSB) galaxies in the Hydra I
cluster of galaxies, with MUSE at ESO-VLT. The majority of LSB galaxies in the
sample (22 in total) are ultra-diffuse galaxies (UDGs). The distribution of
systemic velocities Vsys ranges between 2317 km/s and 5198 km/s and is centred
on the mean velocity of Hydra I (Vsys = 3683 46 km/s). Considering the
mean velocity and the velocity dispersion of the cluster, 17 out of 20 targets
are confirmed cluster members. To assess the quality of the data and
demonstrate the feasibility of the science goals, we report the preliminary
results obtained for one of the sample galaxies, UDG11. For this target, we
derived the stellar kinematics, including the 2-dimensional maps of
line-of-sight velocity and velocity dispersion, constrained age and
metallicity, and studied the globular cluster (GC) population hosted by the
UDG. Results are compared with the available measurements for UDGs and dwarf
galaxies in literature. By fitting the stacked spectrum inside one effective
radius, we find that UDG11 has a velocity dispersion km/s,
it is old ( Gyr), metal-poor ([M/H]=-1.170.11 dex) and has a total
dynamical mass-to-light ratio M, comparable to those observed for
classical dwarf galaxies. The spatially resolved stellar kinematics maps
suggest that UDG11 does not show a significant velocity gradient along either
major or minor photometric axes. We find two GCs kinematically associated with
UDG11. The estimated total number of GCs in UDG11, corrected for the
spectroscopic completeness limit, is , which
corresponds to a GC specific frequency of .Comment: Accepted for publication in Astronomy and Astrophysic
The Fornax Cluster VLT Spectroscopic Survey. I – VIMOS spectroscopy of compact stellar systems in the Fornax core region
We present the results of a wide spectroscopic survey aimed at detecting extragalactic globular clusters (GCs) in the core of the Fornax cluster. About 4500 low resolution spectra (from 4800 to 10000 Å) were observed in 25 VLT/VIMOS masks covering the central 1 deg2 around the dominant galaxy NGC 1399 corresponding to ∼175 kpc galactocentric radius. We describe the methodology used for data reduction and data analysis. We found a total of 387 unique physical objects (372 GCs and 15 ultra compact dwarfs) in the field covered by our observations. Most of these objects lie in the region of NGC1399 halo, with only 10% likely belonging to other giant galaxies 48 of these objects have a literature counterpart. The new VIMOS dataset is complementary to the many GC catalogues already present in the literature and it brings the total number of tracer particles around NGC 1399 to more than 1130 objects. With this comprehensive radial velocity sample we have found that the velocity dispersion of the GC population (equally for red and blue GC populations) shows a relatively sharp increase from low velocity dispersion (∼250 − 350 km s) to high velocity dispersion (∼300 − 400 km s) at projected radius of ≈10 arcmin (∼60 kpc) from the galaxy centre. This suggests that at a projected radius of ≈60 kpc both blue and red GC populations begin to be governed by the dominating Fornax cluster potential, rather than by the central NGC 1399 galaxy potential. This kinematic evidence corroborates similar results found using surface brightness analysis and planetary nebulae kinematics
Galaxy populations in the Hydra i cluster from the VEGAS survey:I. Optical properties of a large sample of dwarf galaxies
At ~50 Mpc, the Hydra I cluster of galaxies is among the closest cluster in
the z=0 Universe, and an ideal environment to study dwarf galaxy properties in
a cluster environment. We exploit deep imaging data of the Hydra I cluster to
construct a new photometric catalog of dwarf galaxies in the cluster core,
which is then used to derive properties of the Hydra I cluster dwarf galaxies
population as well as to compare with other clusters. Moreover, we investigate
the dependency of dwarf galaxy properties on their surrounding environment. The
new Hydra I dwarf catalog contains 317 galaxies with luminosity between
-18.5<<-11.5 mag, a semi-major axis larger than ~200 pc (a=0.84 arcsec),
of which 202 are new detections, previously unknown dwarf galaxies in the Hydra
I central region. We estimate that our detection efficiency reaches 50% at the
limiting magnitude =-11.5 mag, and at the mean effective surface
brightness =26.5 mag/. We present the standard
scaling relations for dwarf galaxies and compare them with other nearby
clusters. We find that there are no observational differences for dwarfs
scaling relations in clusters of different sizes. We study the spatial
distribution of galaxies, finding evidence for the presence of substructures
within half the virial radius. We also find that mid- and high-luminosity
dwarfs (<-14.5 mag) become on average redder toward the cluster center,
and that they have a mild increase in with increasing clustercentric
distance, similar to what is observed for the Fornax cluster. No clear
clustercentric trends are reported with surface brightness and S\'ersic index.
Considering galaxies in the same magnitude-bins, we find that for high and
mid-luminosity dwarfs (<-13.5 mag) the g-r color is redder for the
brighter surface brightness and higher S\'ersic n index objects.Comment: Accepted for publication in A&A. 25 pages, 21 figure
Towards an Ideal In Cell Hybridization-Based Strategy to Discover Protein Interactomes of Selected RNA Molecules
RNA-binding proteins are crucial to the function of coding and non-coding RNAs. The disruption of RNA–protein interactions is involved in many different pathological states. Several computational and experimental strategies have been developed to identify protein binders of selected RNA molecules. Amongst these, ‘in cell’ hybridization methods represent the gold standard in the field because they are designed to reveal the proteins bound to specific RNAs in a cellular context. Here, we compare the technical features of different ‘in cell’ hybridization approaches with a focus on their advantages, limitations, and current and potential future applications
Unraveling unusual X-chromosome patterns during fragile-X syndrome genetic testing
BACKGROUND:
Fragile X syndrome (FXS) is the most common form of inherited intellectual disability (ID). Together with fragile X-associated tremor and ataxia (FXTAS) and fragile X-associated premature ovarian failure (POF)/primary ovarian insufficiency (POI), FXS depends on dysfunctional expression of the FMR1 gene on Xq27.3. In most cases, FXS is caused by a >200 CGG repeats in FMR1 5'-untranslated region (UTR) and by promoter hypermethylation that results in gene silencing. Males and females with unmethylated premutated alleles (repeats between 55 and 200) are at risk for FXTAS and POF/POI.
METHODS:
FXS molecular testing relied on PCR and methylation-specific Southern blot analysis of the FMR1 5'UTR. Atypical Southern blot patterns were studied by X-chromosome microsatellite analysis, copy number dosage at DMD locus, amelogenin gender-marker analysis and array-comparative genomic hybridization (array-CGH).
RESULTS:
Six men affected by ID and three women affected by ID and POF/POI underwent FXS molecular testing. They had normal FMR1 CGG repeats, but atypical X chromosome patterns. Further investigations revealed that the six males had Klinefelter syndrome (XXY), one female was a Turner mosaic (X0/XX) and two women had novel rearrangements involving X chromosome.
CONCLUSIONS:
Diagnostic investigation of atypical patterns at FMR1 locus can address patients and/or their relatives to further verify the condition by performing karyotyping and/or array-CGH