40 research outputs found
WINGS: a WIde-field nearby Galaxy-cluster survey III. Deep near-infrared photometry of 28 nearby clusters
Context. This is the third paper of a series devoted to the WIde-field Nearby
Galaxy-cluster Survey (WINGS).WINGS is a long term project aimed at gathering
wide-field, multiband imaging and spectroscopy of galaxies in a complete sample
of 77 X-ray selected nearby clusters (0.04<z<0.07) located far from the
galactic plane (b>20deg). The main goal of this project is to establish a local
reference sample for evolutionary studies of galaxies and galaxy clusters.
Aims. This paper presents the near-infrared (J,K) photometric catalogs of 28
clusters of the WINGS sample and describes the procedures followed to construct
them. Methods. The raw data has been reduced at CASU and special care has been
devoted to the final coadding, drizzling technique, astrometric solution and
magnitude calibration for the WFCAM pipeline processed data. We have
constructed the photometric catalogs based on the final calibrated coadded
mosaics (0.79 deg2) in J (19 clusters) and K (27 clusters) bands. A customized
interactive pipeline has been used to clean the catalogs and to make mock
images for photometric errors and completeness estimates. Results. We provide
deep near-infrared photometric catalogs (90% complete in detection rate at
total magnitudes J =20.5, K =19.4, and in classification rate at J = 19.5 and K
= 18.5), giving positions, geometrical parameters, total and aperture
magnitudes for all detected sources. For each field we classify the detected
sources as stars, galaxies and objects of "unknown" nature.Comment: Published by A&A501.851 - 15 pages, 3 tables, 13 figures. Catalogs
will be available via CDS and http://web.oapd.inaf.it/wing
Bortezomib modulates CHIT1 and YKL40 in monocyte-derived osteoclast and in myeloma cells
Osteolytic bone disease is a common manifestation of multiple myeloma (MM) that leads to progressive skeleton destruction and is the most severe cause of morbidity in MM patients.It results from increased osteolytic activity and decrease osteoblastic function. Activation of mammalian chitinases CHIT1 and YKL40 is associated with osteoclast (OCs) differentiation and bone digestion. In the current study, we investigated the effect of two Bortezomib’s concentration (BO) (2.5 nM and 5nM) on osteoclastogenesis by analyzing regulation of chitinase expression. OCs exposition to BO was able to inhibit the expression of different OCs markers such as RANK, CTSK, TRAP and MMP9. In addition BO-treatment reduced CHIT1 enzymatic activity and both CHIT1 and YKL40 mRNA expression levels and cytoplasmatic and secreted protein. Moreover, immunofluorescence evaluation of mature OCs showed that BO was able to translocate YKL40 into the nucleus, while CHIT1 remained into the cytoplasm. Since MM cell lines such as U266, SKM-M1 and MM1 showed high levels of CHIT1 activity, we analyzed bone resorption ability of U266 using dentin disc assay resorption pits. Silencing chitinase proteins in U266 cell line with specific siRNAs, resulted in pits number reduction on dentine discs. In conclusion, we showed that BO decreases osteoclastogenesis and reduces bone resorption in OCs and U266 cell line by modulating the chitinases CHIT1 and YKL40. These results indicate that chitinases may be a therapeutic target for bone disease in MM patients
The importance of the local density in shaping the galaxy stellar mass functions
Exploiting the capabilities of four different surveys --- the
Padova-Millennium Galaxy and Group Catalogue (PM2GC), the WIde-field Nearby
Galaxy-cluster Survey (WINGS), the IMACS Cluster Building Survey (ICBS) and the
ESO Distant Cluster Survey (EDisCS) --- we analyze the galaxy stellar mass
distribution as a function of local density in mass-limited samples, in the
field and in clusters from low (z>0.04) to high (z<0.8) redshift. We find that
at all redshifts and in all environments, local density plays a role in shaping
the mass distribution. In the field, it regulates the shape of the mass
function at any mass above the mass limits. In clusters, it seems to be
important only at low masses (log M_ast/M_sun <10.1 in WINGS and log
M_ast/M_sun < 10.4 in EDisCS), otherwise it seems not to influence the mass
distribution. Putting together our results with those of Calvi et al. and
Vulcani et al. for the global environment, we argue that at least at local density is more important than global environment in determining the
galaxy stellar mass distribution, suggesting that galaxy properties are not
much dependent of halo mass, but do depend on local scale processes.Comment: MNRAS accepted, in pres
The red-sequence of 72 WINGS local galaxy clusters
We study the color-magnitude red sequence and blue fraction of 72 X-ray
selected galaxy clusters at z=0.04-0.07 from the WINGS survey, searching for
correlations between the characteristics of the red sequence and the
environment. We consider the slope and scatter of the red sequence, the number
ratio of red luminous-to-faint galaxies, the blue fraction and the fractions of
ellipticals, S0s and spirals that compose the red sequence. None of these
quantities correlate with the cluster velocity dispersion, X-ray luminosity,
number of cluster substructures, BCG prevalence over next brightest galaxies
and spatial concentration of ellipticals. Instead, the properties of the red
sequence depend strongly on local galaxy density. Higher density regions have a
lower RS scatter, a higher luminous-to-faint ratio, a lower blue fraction, and
a lower spiral fraction on the RS. Our results highlight the prominent effect
of the local density in setting the epoch when galaxies become passive and join
the red sequence, as opposed to the mass of the galaxy host structure.Comment: Accepted for publication in A&
SHARDS: A global view of the star formation activity at z~0.84 and z~1.23
In this paper, we present a comprehensive analysis of star-forming galaxies
(SFGs) at intermediate redshifts (z~1). We combine the ultra-deep optical
spectro-photometric data from the Survey for High-z Absorption Red and Dead
Sources (SHARDS) with deep UV-to-FIR observations in the GOODS-N field.
Exploiting two of the 25 SHARDS medium-band filters, F687W17 and F823W17, we
select [OII] emission line galaxies at z~0.84 and z~1.23 and characterize their
physical properties. Their rest-frame equivalent widths
(EW([OII])), line fluxes, luminosities, star formation rates
(SFRs) and dust attenuation properties are investigated. The evolution of the
EW([OII]) closely follows the SFR density evolution of the
universe, with a trend of EW([OII])(1+z) up to
redshift z~1, followed by a possible flattening. The SF properties of the
galaxies selected on the basis of their [OII] emission are compared with
complementary samples of SFGs selected by their MIR and FIR emission, and also
with a general mass-selected sample of galaxies at the same redshifts. We
demonstrate observationally that the UVJ diagram (or, similarly, a cut in the
specific SFR) is only partially able to distinguish the quiescent galaxies from
the SFGs. The SFR-M relation is investigated for the different samples,
yelding a logarithmic slope ~1, in good agreement with previous results. The
dust attenuations derived from different SFR indicators (UV(1600), UV(2800),
[OII], IR) are compared and show clear trends with respect to both the stellar
mass and total SFR, with more massive and highly star-forming galaxies being
affected by stronger dust attenuation.Comment: Replaced to match the accepted version (24 pages, 1 table, 17
figures). Published in ApJ, 812, 155 (2015):
http://stacks.iop.org/0004-637X/812/15
The Shapes of BCGs and normal Ellipticals in Nearby Clusters
We compare the apparent axial ratio distributions of Brightest Cluster
Galaxies (BCGs) and normal ellipticals (Es) in our sample of 75 galaxy clusters
from the WINGS survey. Most BCGs in our clusters (69%) are classified as cD
galaxies. The sample of cDs has been completed by 14 additional cDs (non-BCGs)
we found in our clusters. We find that: (i) Es have triaxial shape, the
triaxiality sharing almost evenly the intrinsic axial ratios parameter space,
with a weak preference for prolateness; (ii) the BCGs have triaxial shape as
well. However, their tendence towards prolateness is much stronger than in the
case of Es. Such a strong prolateness appears entirely due to the sizeable
(dominant) component of cDs inside the WINGS sample of BCGs. In fact, while the
'normal'(non-cD) BCGs do not differ from Es, as far as the shape distribution
is concerned, the axial ratio distribution of BCG_cD galaxies is found to
support quite prolate shapes; (iii) our result turns out to be strongly at
variance with the only similar, previous analysis by Ryden et al.(1993)(RLP93),
where BCGs and Es were found to share the same axial ratio distribution; (iv)
our data suggest that the above discrepancy is mainly caused by the different
criteria that RLP93 and ourselves use to select the cluster samples, coupled
with a preference of cDs to reside in powerful X-ray emitting clusters; (v) the
GIF2 N-body results suggest that the prolateness of the BCGs (in particular the
cDs) could reflect the shape of the associated dark matter halos.Comment: 18 pages, 9 figures, 2 tables. Accepted for publication in MNRA
The star formation history of mass-selected galaxies from the VIDEO survey
© 2014 The Authors Published by Oxford University Press on behalf of the Royal Astronomical SocietyWe measure star formation rates (SFRs) and specific SFRs (SSFRs) of Ks-selected galaxies from the VISTA Deep Extragalactic Observations survey by stacking 1.4 GHz Very Large Array data.We split the sample, which spans 0 < z<3 and stellar masses 108.0 < M*/M⊙ < 1011.5, into elliptical, irregular or starburst galaxies based on their spectral energy distributions. We find that SSFR falls with stellar mass, in agreement with the 'downsizing' paradigm. We consider the dependence of the SSFR-mass slope on redshift: for our full and elliptical samples the slope flattens, but for the irregular and starburst samples the slope is independent of redshift. The rate of SSFR evolution reduces slightly with stellar mass for ellipticals, but irregulars and starbursts co-evolve across stellar masses. Our results for SSFR as a function of stellar mass and redshift are in agreement with those derived from other radio-stacking measurements of mass-selected passive and star-forming galaxies, but inconsistent with those generated from semi-analytic models, which tend to underestimate SFRs and SSFRs. There is a need for deeper high-resolution radio surveys such as those from telescopes like the next-generation MeerKAT in order to probe lower masses at earlier times and to permit direct detections, i.e. to study individual galaxies in detail.Peer reviewe
The evolution of early-type galaxies in clusters from z~ 0.8 to z~ 0: the ellipticity distribution and the morphological mix
We present the ellipticity distribution and its evolution for early-type
galaxies in clusters from z~0.8 to z~0, based on the WIde-field Nearby
Galaxy-cluster Survey (WINGS)(0.04<z<0.07), and the ESO Distant Cluster Survey
(EDisCS)(0.4<z<0.8). We first investigate a mass limited sample and we find
that, above a fixed mass limit, the ellipticity distribution of early-types
noticeably evolves with redshift. In the local Universe there are
proportionally more galaxies with higher ellipticity, hence flatter, than in
distant clusters. This evolution is due partly to the change of the mass
distribution and mainly to the change of the morphological mix with z (among
the early types, the fraction of ellipticals goes from ~70% at high to ~40% at
low-z). Analyzing separately the ellipticity distribution of the different
morphological types, we find no evolution both for ellipticals and S0s.
However, for ellipticals a change with redshift in the median value of the
distributions is detected. This is due to a larger population of very round
(e<0.05) elliptical galaxies at low-z. To compare our finding to previous
studies, we also assemble a magnitude-"delimited" sample that consists of
early-type galaxies on the red sequence with -19.3>M_B+1.208z>-21. Analyzing
this sample, we do not recover exactly the same results of the mass-limited
sample. Hence the selection criteria are crucial to characterize the galaxy
properties: the choice of the magnitude-delimited sample implies the loss of
many less massive galaxies and so it biases the final results. Moreover,
although we are adopting the same selection criteria, our results in the
magnitude-delimited sample are also not in agreement with those of Holden et
al.(2009). This is due to the fact that our and their low-z samples have a
different magnitude distribution because the Holden et al.(2009) sample suffers
from incompleteness at faint magnitudes.Comment: 19 figures and 9 tables, MNRAS in pres
Herschel-ATLAS: the far-infrared properties and star-formation rates of broad absorption line quasi-stellar objects
We have used data from the Herschel-ATLAS at 250, 350 and 500 \mu m to
determine the far-infrared (FIR) properties of 50 Broad Absorption Line Quasars
(BAL QSOs). Our sample contains 49 high-ionization BAL QSOs (HiBALs) and 1
low-ionization BAL QSO (LoBAL) which are compared against a sample of 329
non-BAL QSOs. These samples are matched over the redshift range 1.5 \leq z <
2.3 and in absolute i-band magnitude over the range -28 \leq M_{i} \leq -24. Of
these, 3 BAL QSOs (HiBALs) and 27 non-BAL QSOs are detected at the > 5 sigma
level. We calculate star-formation rates (SFR) for our individually detected
HiBAL QSOs and the non-detected LoBAL QSO as well as average SFRs for the BAL
and non-BAL QSO samples based on stacking the Herschel data. We find no
difference between the HiBAL and non-BAL QSO samples in the FIR, even when
separated based on differing BAL QSO classifications. Using Mrk 231 as a
template, the weighted mean SFR is estimated to be \approx240\pm21 M_{\odot}
yr^{-1} for the full sample, although this figure should be treated as an upper
limit if AGN-heated dust makes a contribution to the FIR emission. Despite
tentative claims in the literature, we do not find a dependence of {\sc C\,iv}
equivalent width on FIR emission, suggesting that the strength of any outflow
in these objects is not linked to their FIR output. These results strongly
suggest that BAL QSOs (more specifically HiBALs) can be accommodated within a
simple AGN unified scheme in which our line-of-sight to the nucleus intersects
outflowing material. Models in which HiBALs are caught towards the end of a
period of enhanced spheroid and black-hole growth, during which a wind
terminates the star-formation activity, are not supported by the observed FIR
properties.Comment: 11 pages, 4 figures, 4 tables. Accepted for publication in MNRA
ACCESS III: The Nature of Star Formation in the Shapley Supercluster
We present a joint analysis of panoramic Spitzer/MIPS mid-infrared and GALEX
ultraviolet imaging of the Shapley supercluster at z=0.048. Combining this with
spectra of 814 supercluster members and 1.4GHz radio continuum maps, this
represents the largest complete census of star-formation (both obscured and
unobscured) in local cluster galaxies to date, reaching SFRs~0.02Msun/yr. We
take advantage of this comprehensive panchromatic dataset to perform a detailed
analysis of the nature of star formation in cluster galaxies, using several
quite independent diagnostics of the quantity and intensity of star formation
to develop a coherent view of the types of star formation within cluster
galaxies. We observe a robust bimodality in the infrared (f_24/f_K) galaxy
colours, which we are able to identify as another manifestation of the broad
split into star-forming spiral and passive elliptical galaxy populations seen
in UV-optical surveys. This diagnostic also allows the identification of
galaxies in the process of having their star formation quenched as the infrared
analogue to the UV "green valley" population. The bulk of supercluster galaxies
on the star-forming sequence have specific-SFRs consistent with local field
specific-SFR-M* relations, and form a tight FIR-radio correlation confirming
that their FIR emission is due to star formation. We show that 85% of the
global SFR is quiescent star formation within spiral disks, as manifest by the
observed sequence in the IRX-beta relation being significantly offset from the
starburst relation of Kong et al. (2004), while their FIR-radio colours
indicate dust heated by low-intensity star formation. Just 15% of the global
SFR is due to nuclear starbursts. The vast majority of star formation seen in
cluster galaxies comes from normal infalling spirals who have yet to be
affected by the cluster environment.Comment: 17 pages, 9 figures. Accepted for publication in MNRA