27 research outputs found
The Intra-Group Baryons in the LEO I Pair From the VST Early-Type GAlaxy Survey
In this paper we present the deep, wide-field and multi-band imaging of the LEO I pair NGC 3379-NGC 3384, from the VST Early-type GAlaxy Survey (VEGAS). The main goal of this study is to map the intra-group baryons in the pair, in the form of diffuse light and globular clusters (GCs). Taking advantage from the large covered area, which extends for ∼ 3.9 square degrees around the pair, and the long integration time, we can map the light distribution out to ∼ 63 kpc and down to ∼ 30 mag/arcsec2 in the g band and ∼ 29 mag/arcsec2 in the r band, deeper than previous data available for this target. The map of the intra-group light (IGL) presents two very faint (μg ∼ 28-29 mag/arcsec2) streams protruding from the brightest group member NGC 3379 and elongated toward North-West and South. We estimate that the fraction of the stellar halo around NGC 3379 plus the intra-group light is (Formula presented.) in both g and r bands, with an average color g-r = 0.75 ± 0.04 mag. The color distribution of the GCs appears multi-modal, with two dominant peaks at (u-r) = 1.8 mag and (u-r) = 2.1 mag, respectively. The GC population stretches from North-East to South-West and from North-West to South of the pair, in the last case overlapping with the streams of IGL, as well as the PNe distribution found by Hartke et al. (Hartke et al., A&A, 2020, 642, A46) and Hartke et al. (Hartke et al., 2022). Since these structures are elongated in the direction of the two nearby galaxies M96 and NGC 3338, they could be the remnant of a past gravitational interactions with the pair.</p
Does the virial mass drive the intra-cluster light? The relationship between the ICL and M from VEGAS
In this Letter we revisit the relationship between the fraction of the
intra-cluster light (ICL) and both the virial mass and the fraction of Early
Type Galaxies in the host halo. This is based on a statistically significant
and homogeneous sample of 22 groups and clusters of galaxies in the local
Universe (), obtained with the VST Early-type GAlaxy Survey
(VEGAS). Taking advantage of the long integration time and large area of the
VEGAS images, we are able to map the galaxy outskirts and ICL down to
29-30 mag/arcsec and out to hundreds of kpc. With this data-set, we
have expanded the sample of ICL measurements, doubling the previous measures
available from the literature for z 0.05. The main result of this work
is the lack of any significant trend between the fraction of ICL and the virial
mass of the host environment, covering a wide range of virial masses (
), in agreement with some
theoretical studies. Since the new data points are all derived with the same
methodology and from the same observational setup, and all have comparable
depth, the large observed scatter indicates an intrinsic variation in the ICL
fraction.On the other hand, there is a weak relation between the fraction of
ICL and the fraction of Early Type Galaxies in the host halo, where a larger
fraction of ICL is found in groups and clusters of galaxies dominated by
earlier morphological types, indicating a connection between the ICL and the
dynamical state of the host system.Comment: Letter to the editor, accepted for publication in A&A. 8 pages, 3
figure
The VST Early-type GAlaxy Survey: Exploring the Outskirts and Intra-cluster Regions of Galaxies in the Low-surface-brightness Regime
The VST Early-type GAlaxy Survey (VEGAS) is a deep, multi-band (u, g, r, i)
imaging survey, carried out with the 2.6-metre VLT Survey Telescope (VST) at
ESO's Paranal Observatory in Chile. VEGAS combines the wide (1-square-degree)
OmegaCAM imager and long integration times, together with a specially designed
observing strategy. It has proven to be a gold mine for studies of features at
very low surface brightness, down to levels of mu_g~27-30 magnitudes
arcsec^(-2), over 5-8 magnitudes fainter than the dark sky at Paranal. In this
article we highlight the main science results obtained with VEGAS observations
of galaxies across different environments, from dense clusters of galaxies to
unexplored poor groups and in the field.Comment: Published in The Messenger, vol. 183, p. 25-2
Preparing for low surface brightness science with the Vera C. Rubin Observatory: A Comparison of Observable and Simulated Intracluster Light Fractions
Intracluster Light (ICL) provides an important record of the interactions
galaxy clusters have undergone. However, we are limited in our understanding by
our measurement methods. To address this we measure the fraction of cluster
light that is held in the Brightest Cluster Galaxy and ICL (BCG+ICL fraction)
and the ICL alone (ICL fraction) using observational methods (Surface
Brightness Threshold-SB, Non-Parametric Measure-NP, Composite Models-CM,
Multi-Galaxy Fitting-MGF) and new approaches under development (Wavelet
Decomposition-WD) applied to mock images of 61 galaxy clusters (14<log10
M_200c/M_solar <14.5) from four cosmological hydrodynamical simulations. We
compare the BCG+ICL and ICL fractions from observational measures with those
using simulated measures (aperture and kinematic separations). The ICL
fractions measured by kinematic separation are significantly larger than
observed fractions. We find the measurements are related and provide equations
to estimate kinematic ICL fractions from observed fractions. The different
observational techniques give consistent BCG+ICL and ICL fractions but are
biased to underestimating the BCG+ICL and ICL fractions when compared with
aperture simulation measures. Comparing the different methods and algorithms we
find that the MGF algorithm is most consistent with the simulations, and CM and
SB methods show the smallest projection effects for the BCG+ICL and ICL
fractions respectively. The Ahad (CM), MGF and WD algorithms are best set up to
process larger samples, however, the WD algorithm in its current form is
susceptible to projection effects. We recommend that new algorithms using these
methods are explored to analyse the massive samples that Rubin Observatory's
Legacy Survey of Space and Time will provide.Comment: Submitted for publication in MNRAS, posted to arXiv after responding
to two positive rounds of referee comments. Key results in Figs 3, 5, 6 and
1
Preparing for low surface brightness science with the Vera C. Rubin Observatory: a comparison of observable and simulated intracluster light fractions
Intracluster light (ICL) provides an important record of the interactions galaxy clusters have undergone. However, we are limited in our understanding by our measurement methods. To address this, we measure the fraction of cluster light that is held in the Brightest Cluster Galaxy and ICL (BCG+ICL fraction) and the ICL alone (ICL fraction) using observational methods (surface brightness threshold-SB, non-parametric measure-NP, composite models-CM, and multi-galaxy fitting-MGF) and new approaches under development (wavelet decomposition-WD) applied to mock images of 61 galaxy clusters (14 <log10M200c/M⊙ < 14.5) from four cosmological hydrodynamical simulations. We compare the BCG+ICL and ICL fractions from observational measures with those using simulated measures (aperture and kinematic separations). The ICL fractions measured by kinematic separation are significantly larger than observed fractions. We find the measurements are related and provide equations to estimate kinematic ICL fractions from observed fractions. The different observational techniques give consistent BCG+ICL and ICL fractions but are biased to underestimating the BCG+ICL and ICL fractions when compared with aperture simulation measures. Comparing the different methods and algorithms, we find that the MGF algorithm is most consistent with the simulations, and CM and SB methods show the smallest projection effects for the BCG+ICL and ICL fractions, respectively. The Ahad (CM), MGF, and WD algorithms are best set up to process larger samples; however, the WD algorithm in its current form is susceptible to projection effects. We recommend that new algorithms using these methods are explored to analyse the massive samples that Rubin Observatory’s Legacy Survey of Space and Time will provide
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
Prognostic factors of lung cancer in lymphoma survivors (the LuCiLyS study)
Background
Second cancer is the leading cause of death in lymphoma survivors, with lung cancer representing the most common solid tumor. Limited information exists about the treatment and prognosis of second lung cancer following lymphoma. Herein, we evaluated the outcome and prognostic factors of Lung Cancer in Lymphoma Survivors (the LuCiLyS study) to improve the patient selection for lung cancer treatment.
Methods
This is a retrospective multicentre study including consecutive patients treated for lymphoma disease that subsequently developed non-small cell lung cancer (NSCLC). Data regarding lymphoma including age, symptoms, histology, disease stage, treatment received and lymphoma status at the time of lung cancer diagnosis, and data on lung carcinoma as age, smoking history, latency from lymphoma, symptoms, histology, disease stage, treatment received, and survival were evaluated to identify the significant prognostic factors for overall survival.
Results
Our study population included 164 patients, 145 of which underwent lung cancer resection. The median overall survival was 63 (range, 58–85) months, and the 5-year survival rate 54%. At univariable analysis no-active lymphoma (HR: 2.19; P=0.0152); early lymphoma stage (HR: 1.95; P=0.01); adenocarcinoma histology (HR: 0.59; P=0.0421); early lung cancer stage (HR: 3.18; P<0.0001); incidental diagnosis of lung cancer (HR: 1.71; P<0.0001); and lung cancer resection (HR: 2.79; P<0.0001) were favorable prognostic factors. At multivariable analysis, no-active lymphoma (HR: 2.68; P=0.004); early lung cancer stage (HR: 2.37; P<0.0001); incidental diagnosis of lung cancer (HR: 2.00; P<0.0001); and lung cancer resection (HR: 2.07; P<0.0001) remained favorable prognostic factors. Patients with non-active lymphoma (n=146) versus those with active lymphoma (n=18) at lung cancer diagnosis presented better median survival (64 vs. 37 months; HR: 2.4; P=0.02), but median lung cancer specific survival showed no significant difference (27 vs. 19 months; HR: 0.3; P=0.17).
Conclusions
The presence and/or a history of lymphoma should not be a contraindication to resection of lung cancer. Inclusion of lymphoma survivors in a lung cancer-screening program may lead to early detection of lung cancer, and improve the survival
Covid-19 And Rheumatic Autoimmune Systemic Diseases: Role of Pre-Existing Lung Involvement and Ongoing Treatments
The Covid-19 pandemic may have a deleterious impact on patients with autoimmune systemic diseases (ASD) due to their deep immune-system alterations
Lobectomy with angioplasty. Which is the best technique for pulmonary artery reconstruction?
Lobectomies with bronchial and/or vascular reconstruction are conservative procedures aimed at managing locally advanced lung cancer, avoiding a pneumonectomy. Considering morbidity, mortality and the functional consequences of a pneumonectomy, such procedures must be in the technical armamentarium of every thoracic surgeon. Vascular reconstruction of the pulmonary artery (PA) is seldom performed with or without the bronchial sleeve resection. Both functional and oncologic outcomes have been reported to be better than after a pneumonectomy. Different technical options are now available but some aspects and technical details are not standardized. Indications, possible complications, planning and even definitions need to be more solid to allow for definitive improvement in such procedures. This analysis is aimed at assessing the acquired technical data with special emphasis on the PA reconstruction with autologous tissues