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

Early Diagnosis and Treatment of Purine Nucleoside Phosphorylase (PNP) Deficiency through TREC-Based Newborn Screening

Purine nucleoside phosphorylase (PNP) deficiency is a rare inherited disorder, resulting in severe combined immunodeficiency. To date, PNP deficiency has been detected in newborn screening only through the use of liquid chromatography tandem mass spectrometry. We report the first case in which PNP deficiency was detected by TREC analysis

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 $\pm$ 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 $\sigma = 20 \pm 8$ km/s, it is old ($10\pm1$ Gyr), metal-poor ([M/H]=-1.17$\pm$0.11 dex) and has a total dynamical mass-to-light ratio M$/L_V\sim 14$, 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 $N_{GC}= 5.9^{+2.2}_ {-1.8}$, which corresponds to a GC specific frequency of $S_N = 8.4^{+3.2}_{-2.7}$.Comment: Accepted for publication in Astronomy and Astrophysic

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<$M_r$<-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 $M_r$=-11.5 mag, and at the mean effective surface brightness $\overline{\mu}_{e,r}$=26.5 mag/$arcsec^2$. 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 ($M_r$<-14.5 mag) become on average redder toward the cluster center, and that they have a mild increase in $R_e$ 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 ($M_r$<-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

The association between perceived emotional support, maternal mood, salivary cortisol, salivary cortisone, and the ratio between the two compounds in response to acute stress in second trimester pregnant women

OBJECTIVE: Little is known about the effect of social support on the reactivity of the hypothalamic-pituitary-adrenal (HPA) axis during pregnancy. Moreover, when investigating the HPA axis most studies do not consider the activity of 11β-hydroxysteroid dehydrogenase type 2 (11β-HSD2), an enzyme within the salivary glands that inactivates cortisol to cortisone. This study explores the association between perceived emotional support and the maternal psychobiological stress response to a standardized naturalistic stressor by assessing maternal mood and the reactivity of salivary cortisol (SalF), salivary cortisone (SalE), and the SalE/(E+F) ratio as a marker of 11β-HSD2 activity. METHODS: Repeated saliva samples and measures of maternal mood were obtained from 34 healthy second trimester pregnant women undergoing amniocentesis which served as a psychological stressor. The pregnant women additionally responded to a questionnaire of perceived emotional support and provided sociodemographic (e.g., maternal educational degree) and pregnancy-specific data (e.g., planned versus unplanned pregnancy). RESULTS: Perceived emotional support neither showed a significant effect on mood nor on the SalF or SalE response to stress. However, a moderately strong positive association was found between perceived emotional support and SalE/(E+F) (r=.49). Additionally, the final regression analysis revealed a significant negative relationship between educational degree, planned/unplanned pregnancy and SalE/(E+F). CONCLUSION: Findings suggest a higher metabolization of cortisol to cortisone in pregnant women with higher emotional support. In contrast, higher maternal education and unplanned pregnancy appear to be associated with decreased salivary 11β-HSD2 activity. The current study emphasizes the importance of taking the activity of 11β-HSD2 into account when examining SalF

Second-Trimester Amniotic Fluid Corticotropin-Releasing Hormone and Urocortin in Relation to Maternal Stress and Fetal Growth in Human Pregnancy

This study explored the association between the acute psychobiological stress response, chronic social overload and amniotic fluid corticotropin corticotropin-releasing hormone (CRH) and urocortin (UCN) in 34 healthy, second-trimester pregnant women undergoing amniocentesis. The study further examined the predictive value of second-trimester amniotic fluid CRH and UCN for fetal growth and neonatal birth outcome. The amniocentesis served as a naturalistic stressor, during which maternal state anxiety and salivary cortisol was measured repeatedly and an aliquot of amniotic fluid was collected. The pregnant women additionally completed a questionnaire on chronic social overload. Fetal growth parameters were obtained at amniocentesis using fetal ultrasound biometry and at birth from medical records. The statistical analyses revealed that the acute maternal psychobiological stress response was unassociated with the amniotic fluid peptides, but that maternal chronic overload and amniotic CRH were positively correlated. Moreover, amniotic CRH was negatively associated with fetal size at amniocentesis and positively with growth in size from amniocentesis to birth. Hardly any studies have previously explored whether acute maternal psychological stress influences fetoplacental CRH or UCN levels significantly. Our findings suggest that 1) chronic, but not acute maternal stress may affect fetoplacental CRH secretion and that 2) CRH is complexly involved in fetal growth processes as previously shown in animals