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We investigate the properties of the mixed-mode (RRd) RR Lyrae (RRL) variables in the Fornax dwarf spheroidal (dSph) galaxy by using $B$- and $V$-band time series collected over twenty-four years. We compare the properties of the RRds in Fornax with those in the Magellanic Clouds and in nearby dSphs, with special focus on Sculptor. We found that the ratio of RRds over the total number of RRLs decreases with metallicity. Typically, dSphs have very few RRds with 0.49$\ltsim P_0 \ltsim $0.53 days, but Fornax fills this period gap in the Petersen diagram (ratio between first overtone over fundamental period versus fundamental period). We also found that the distribution in the Petersen diagram of Fornax RRds is similar to SMC RRds, thus suggesting that their old stars have a similar metallicity distribution. We introduce the Period-Amplitude RatioS (PARS) diagram, a new pulsation diagnostics independent of distance and reddening. We found that LMC RRds in this plane are distributed along a short- and a long-period sequence that we identified as the metal-rich and the metal-poor component. These two groups are also clearly separated in the Petersen and Bailey (luminosity amplitude versus logarithmic period) diagrams. These circumstantial evidence indicates that the two groups have different evolutionary properties. All the pulsation diagnostics adopted in this investigation suggest that old stellar populations in Fornax and Sculptor dSphs underwent different chemical enrichment histories. Fornax RRds are similar to SMC RRds, while Sculptor RRds are more similar to the metal-rich component of the LMC RRds., Comment: Accepted for publication by MNRAS

Glioblastoma is the most malignant primary brain tumor and is still in need of effective medical treatment. We isolated patient-derived glioblastoma cells showing high GD2 antigen expression representing a potential target for CAR T strategy. Data highlighted a robust GD2 CAR antitumor potential in 2D and 3D glioblastoma models associated with a significant and CAR T-restricted increase of selected cytokines. Interestingly, immunosuppressant TGF β1, expressed in all co-cultures, did not influence antitumor activity. The orthotopic NOD/SCID models using primary glioblastoma cells reproduced human histopathological features. Considering still-conflicting data on the delivery route for targeting brain tumors, we compared intracerebral versus intravenous CAR T injections. We report that the intracerebral route significantly increased the length of survival time in a dose-dependent manner, without any side effects. Collectively, the proposed anti-GD2 CAR can counteract human glioblastoma potentially opening a new therapeutic option for a still incurable cancer.

We performed photometric observations of the binary near-Earth asteroid (65803) Didymos in support of the Double Asteroid Redirection Test (DART) mission that will test the Kinetic Impactor technology for diverting dangerous asteroids. It will hit the Didymos secondary, called Dimorphos, on 2022 September 26. We observed Didymos with 11 telescopes with diameters from 3.5 to 10.4 m during four apparitions in 2015–2021, obtaining data with rms residuals from 0.006 to 0.030 mag. We analyzed the light-curve data and decomposed them into the primary rotational and secondary orbital light curves. We detected 37 mutual eclipse/occultation events between the binary system components. The data presented here, in combination with 18 mutual events detected in 2003, provide the basis for modeling the Dimorphos orbit around the Didymos primary. The orbit modeling is discussed in detail by Scheirich & Pravec and Naidu et al. The primary light curves were complex, showing multiple extrema on some epochs. They suggest a presence of complex topography on the primary’s surface that is apparent in specific viewing/illumination geometries; the primary shape model by Naidu et al. (Icarus 348, 113777, 2020) needs to be refined. The secondary rotational light-curve data were limited and did not provide a clear solution for the rotation period and equatorial elongation of Dimorphos. We define the requirements for observations of the secondary light curve to provide the needed information on Dimorphos’s rotation and elongation when Didymos is bright in 2022 July–September before the DART impact.

We present accurate and deep multi-band ($g,r,i$) photometry of the Local Group dwarf irregular galaxy NGC 6822. The images were collected with wide field cameras at 2m/4m- (INT,CTIO,CFHT) and 8m-class telescopes (SUBARU) covering a 2 square degrees FoV across the center of the galaxy. We performed PSF photometry of $\approx$7,000 CCD images and the final catalog includes more than 1 million objects. We developed a new approach to identify candidate field and galaxy stars, and performed a new estimate of the galaxy center by using old stellar tracers finding that it differs by 1.15 (RA) and 1.53 (DEC) arcmin from previous estimates. We also found that young (Main Sequence, Red Supergiants), intermediate (Red Clump, Asymptotic Giant Branch [AGB]) and old (Red Giant Branch [RGB]) stars display different radial distributions. Old stellar population is spherically distributed and extends to radial distances larger than previously estimated ($\sim$1 degree). The young population shows a well defined bar and a disk-like distribution, as suggested by radio measurements, that is off-center compared with old population. We discuss pros and cons of the different diagnostics adopted to identify AGB stars and develop new ones based on optical-NIR-MIR color-color diagrams (CCDs) to characterize Oxygen and Carbon (C) rich stars. We found a mean population ratio between Carbon and M-type (C/M) stars of 0.67$\pm$0.08 (optical/NIR/MIR) and we used the observed C/M ratio with empirical C/M-metallicity relations to estimate a mean iron abundance of [Fe/H]$\sim$-1.25 ($\sigma$=0.04 dex) that agrees quite well with literature estimates., Comment: Accepted for publication in ApJ, 34 pages, 22 figures, 6 tables

Classical Cepheids are the most popular distance indicators and tracers of young stellar populations. The key advantage is that they are bright and they can be easily identified in Local Group and Local Volume galaxies. Their evolutionary and pulsation properties depend on their chemical abundances. The main aim of this investigation is to perform a new and accurate abundance analysis of two tens of calibrating Galactic Cepheids using high spectral resolution (R$\sim$40,000-115,000) and high S/N spectra ($\sim$400) covering the entire pulsation cycle. We focus our attention on possible systematics affecting the estimate of atmospheric parameters and elemental abundances along the pulsation cycle. We cleaned the line list by using atomic transition parameters based on laboratory measurements and by removing lines that are either blended or display abundance variations along the pulsation cycle. The spectroscopic approach that we developed brings forward small dispersions in the variation of the atmospheric parameters ($\sigma$($T_{\rm eff}$)$\sim$50 K, $\sigma$($\log{g}$)$\sim$0.2 dex, and $\sigma$($\xi$)$\sim$0.2 km/s) and in the abundance of both iron ($\lesssim$ 0.05 dex) and alpha elements ($\lesssim$0.10 dex) over the entire pulsation cycle. We also provide new and accurate effective temperature templates by splitting the calibrating Cepheids into four different period bins, ranging from short to long periods. For each period bin, we performed an analytical fit with Fourier series providing $\theta = 5040/{T_{\rm eff}}$ as a function of the pulsation phase. The current findings are a good viaticum to trace the chemical enrichment of the Galactic thin disk by using classical Cepheids and a fundamental stepping stone for further investigations into the more metal-poor regime typical of Magellanic Cepheids., Comment: 31 pages, 23 figures (out of which 11 are in the appendices A and B), to be published in the Astronomy & Astrophysics journal

We present our analysis of a large sample (over 150k) of candidate Galactic RR Lyrae (RRL) stars for which we derived high quality photometry at UV, optical and infrared wavelengths, using data from publicly available surveys. For a sub-sample of these stars (~2,400 fundamental mode field RRLs) we have measured their individual metallicity using the Delta S method, resulting in the largest and most homogeneous spectroscopic data set collected for RRLs. We use this sample to study the metallicity distribution in the Galactic Halo, including the long-standing problem of the Oosterhoff dichotomy among Galactic globular clusters. We also analyze the dependence of their pulsation properties, and in particular the shape of their infrared light curves, from their [Fe/H] abundance., Proc. of "The RR Lyrae and Cepheid Conference 2019: Frontiers of Classical Pulsators - Theory and Observations", held in Cloudcroft, NM, 13-18 October 2019

International audience; We present a chemo-dynamical study of the Orphan stellar stream using a catalog of RR Lyrae pulsating variable stars for which photometric, astrometric, and spectroscopic data are available. Employing low-resolution spectra from the Sloan Digital Sky Survey (SDSS), we determined line-of-sight velocities for individual exposures and derived the systemic velocities of the RR Lyrae stars. In combination with the stars’ spectroscopic metallicities and Gaia EDR3 astrometry, we investigated the northern part of the Orphan stream. In our probabilistic approach, we found 20 single mode RR Lyrae variables likely associated with the Orphan stream based on their positions, proper motions, and distances. The acquired sample permitted us to expand our search to nonvariable stars in the SDSS dataset, utilizing line-of-sight velocities determined by the SDSS. We found 54 additional nonvariable stars linked to the Orphan stream. The metallicity distribution for the identified red giant branch stars and blue horizontal branch stars is, on average, −2.13 ± 0.05 dex and −1.87 ± 0.14 dex, with dispersions of 0.23 and 0.43 dex, respectively. The metallicity distribution of the RR Lyrae variables peaks at −1.80 ± 0.06 dex and a dispersion of 0.25 dex. Using the collected stellar sample, we investigated a possible link between the ultra-faint dwarf galaxy Grus II and the Orphan stream. Based on their kinematics, we found that both the stream RR Lyrae and Grus II are on a prograde orbit with similar orbital properties, although the large uncertainties on the dynamical properties render an unambiguous claim of connection difficult. At the same time, the chemical analysis strongly weakens the connection between both. We argue that Grus II in combination with the Orphan stream would have to exhibit a strong inverse metallicity gradient, which to date has not been detected in any Local Group system.

KiDS data releases consist of ~1 square degree tiles that have been successfully observed in all four survey filters (u,g,r,i). The second data release (KiDS-ESO-DR2) was available in February 2015 and contains imaging data, masks and single-band source lists for all tiles observed in all four filters for which observations were completed during the second year of regular operations (1 October 2012 to 31 September 2013), a total of 98 tiles. Apart from the data products mentioned above, KiDS-ESO-DR2 also provides a multi-band source catalogue based on the combined set of 148 tiles released in the first two data releases. A complete list of all tiles with data quality parameters can be found on the KiDS website: http://kids.strw.leidenuniv.nl/DR2/ (1 data file).

We have started a systematic search for strong lens candidates in the ESO public survey KiDS based on the visual inspection ofmassive galaxies in the redshift range 0:1 < z < 0:5. As a pilot program we have inspected 100 deg2, which overlap with SDSS and where there are known lenses to use as a control sample. Taking advantage of the superb image quality of VST/OmegaCAM, the colour information and accurate model subtracted images, we have found 18 new lens candidates, for which spectroscopic confirmation will be needed to confirm their lensing nature and study the mass profile of the lensing galaxies. © Springer International Publishing Switzerland 2016.

The VLT Survey Telescope (VST) is the 2.6-m survey telescope of the European Southern Observatory (ESO) for the visible band, the largest in the world designed to exclusively survey the skies in visible light. It is equipped with the OmegaCAM 268 Mpix 16 × 16 K CCD camera, covering a wide-field of 1 deg2 with 0.21 arcsec/pixel resolution. We provide a short history of the project and an overview of the instrument, summarizing the delivered performance.

We present the Capodimonte Deep Field (OACDF), a deep field covering an area of 0.5 square degrees in the B, V, R optical bands plus six medium-band filters in the wavelength range 773--913 nm. The field reaches the following limiting AB magnitudes: B~25.3, V~24.8 and R~25.1 and contains about 50000 extended sources in the AB magnitude range 18 < R < 25 . Hence, it is intermediate between deep pencil beam surveys and very wide but shallow surveys. The main scientific goal of the OACDF is the identification and characterization of early-type field galaxies at different look-back times in order to study different scenarios of galaxy formation. Parallel goals include the search for groups and clusters of galaxies and the search for rare and peculiar objects (gravitational lenses, QSOs, halo White Dwarfs). In this paper we describe the OACDF data reduction, the methods adopted for the extraction of the photometric catalogs, the photometric calibration and the quality assessment of the catalogs by means of galaxy number counts, spectroscopic and photometric redshifts and star colors. We also present the first results of the search for galaxy overdensities. The depth of the OACDF and its relatively large spatial coverage with respect to pencil beam surveys make it a good tool for further studies of galaxy formation and evolution in the redshift range 0--1, as well as for stellar studies., 24 pages, accepted for pubblication on A&A

The Public European Southern Observatory Spectroscopic Survey of Transient Objects (PESSTO) began as a public spectroscopic survey in April 2012. We describe the data reduction strategy and data products which are publicly available through the ESO archive as the Spectroscopic Survey Data Release 1 (SSDR1). PESSTO uses the New Technology Telescope with EFOSC2 and SOFI to provide optical and NIR spectroscopy and imaging. We target supernovae and optical transients brighter than 20.5mag for classification. Science targets are then selected for follow-up based on the PESSTO science goal of extending knowledge of the extremes of the supernova population. The EFOSC2 spectra cover 3345-9995A (at resolutions of 13-18 Angs) and SOFI spectra cover 0.935-2.53 micron (resolutions 23-33 Angs) along with JHK imaging. This data release contains spectra from the first year (April 2012 - 2013), consisting of all 814 EFOSC2 spectra and 95 SOFI spectra (covering 298 distinct objects), in standard ESO Phase 3 format. We estimate the accuracy of the absolute flux calibrations for EFOSC2 to be typically 15%, and the relative flux calibration accuracy to be about 5%. The PESSTO standard NIR reduction process does not yet produce high accuracy absolute spectrophotometry but the SOFI JHK imaging will improve this. Future data releases will focus on improving the automated flux calibration of the data products., Comment: Accepted for publication in A&A. Describes the PESSTO public data products. All reduced data available from the ESO archive. See http://www.pessto.org for download instructions

We present optical and near-infrared UBVRIJHK photometry of stars in the Galactic globular cluster M4 (NGC 6121) based upon a large corpus of observations obtained mainly from public astronomical archives. We concentrate on the RR Lyrae variable stars in the cluster, and make a particular effort to accurately reidentify the previously discovered variables. We have also discovered two new probable RR Lyrae variables in the M4 field: one of them by its position on the sky and its photometric properties is a probable member of the cluster, and the second is a probable background (bulge?) object. We provide accurate equatorial coordinates for all 47 stars identified as RR Lyraes, new photometric measurements for 46 of them, and new period estimates for 45. We have also derived accurate positions and mean photometry for 34 more stars previously identified as variable stars of other types, and for an additional five non-RR Lyrae variable stars identified for the first time here. We present optical and near-infrared color-magnitude diagrams for the cluster and show the locations of the variable stars in them. We present the Bailey (period-amplitude) diagrams and the period-frequency histogram for the RR Lyrae stars in M4 and compare them to the corresponding diagrams for M5 (NGC 5904). We conclude that the RR Lyrae populations in the two clusters are quite similar in all the relevant properties that we have considered. The mean periods, pulsation-mode ratios, and Bailey diagrams of these two clusters show support for the recently proposed "Oosterhoff-neutral" classification., Comment: 33 pages, 16 figures, 7 tables

We present new and accurate optical photometry of the Bulge globular cluster NGC 6528. The images were collected with ACS at HST and together with WFC3 (UVIS, IR) allowed us to measure the proper motion to separate cluster and field stars. We adopted two empirical calibrators and we found that NGC 6528 is coeval with and more metal-rich than 47 Tuc. Moreover, it appears older and more metal-poor than the super-metal-rich old open cluster NGC 6791. We also performed a preliminary analysis of field stellar populations located around NGC 6528 and NGC 6522 by using ground-based near-infrared photometry collected with SOFI at NTT. The comparison of evolved stellar components (red giant branch, red horizontal branch, red clump stars) indicates that they share similar properties in this region of the Baade's Window., 7 pages, 2 figures. Proceeding of the Symposium "Stellar Populations: 55 years after the Vatican conference", EWASS, Rome 1-6 Jul 2012

We present new and accurate near-infrared (NIR) J, K-band time series data for the Galactic globular cluster (GC) M5 = NGC5904. Data were collected with SOFI at the NTT (71 J + 120 K images) and with NICS at the TNG (25 J + 22 K images) and cover two orthogonal strips across the center of the cluster of \approx 5 \times 10 arcmin^{2} each. These data allowed us to derive accurate mean K-band magnitudes for 52 fundamental (RR_{ab}) and 24 first overtone (RR_{c}) RR Lyrae stars. Using this sample of RR Lyrae stars, we find that the slope of the K-band Period Luminosity (PLK) relation (-2.33 \pm 0.08) agrees quite well with similar estimates available in the literature. We also find, using both theoretical and empirical calibrations of the PLK relation, a true distance to M5 of (14.44 \pm 0.02) mag. This distance modulus agrees very well (1\sigma) with distances based on main sequence fitting method and on kinematic method (14.44 \pm 0.41 mag, \citealt{rees_1996}), while is systematically smaller than the distance based on the white dwarf cooling sequence (14.67 \pm 0.18 mag, \citealt{layden2005}), even if with a difference slightly larger than 1\sigma. The true distance modulus to M5 based on the PLJ relation (14.50 \pm 0.08 mag) is in quite good agreement with the distance based on the PLK relation further supporting the use of NIR PL relations for RR Lyrae stars to improve the precision of the GC distance scale., Comment: 19 pages, 6 figures, accepted for publication in MNRAS

We introduce a new parameter {\Delta}{\xi} - the difference in magnitude between the red giant branch (RGB) bump and a point on the main sequence (MS) at the same color as the bump, the "benchmark" - to estimate the helium content in old stellar systems. Its sensitivity to helium is linear over the entire metallicity range, it is minimally affected by age, uncertainties in the photometric zero-point, reddening or the effects of evolution on the horizontal branch. The two main drawbacks are the need for precise and large photometric data sets, and a strong dependence of the {\Delta}Y/{\Delta}{\xi} slope on metallicity. To test the {\Delta}{\xi} parameter we selected 22 Galactic Globular Clusters (GGCs) with low foreground reddening, a broad range of iron abundance and precise, relatively deep, and homogeneous multi-band (B,V,I) photometry. We found that the observed {\Delta}{\xi} and those predicted from {\alpha}-enhanced models agree quite well if we assume Y=0.20. Comparison with canonical primordial helium content models (Y=0.245, {\Delta}Y/{\Delta}Z=1.4) indicates that the observed {\Delta}{\xi} values are systematically smaller than predicted. The outcome is the same if predicted parameters are based on models that take into account also CNO enhancements and becomes even larger if we consider He-enhanced models. These findings suggest that current stellar evolutionary models overestimate the luminosity of the RGB bump. We also found that including envelope overshooting can eliminate the discrepancy, as originally suggested by Alongi et al. (1993, aaps, 97, 851). The {\Delta}{\xi} parameter of GGCs, in spite of the possible limitations concerning the input physics of current evolutionary models, provides an independent detection of pre-stellar helium at least at the 5{\sigma} level.

We present new multiband photometry for the Galactic globular cluster IC 4499 extending well past the main-sequence turn-off in the U, B, V, R, I and DDO51 bands. This photometry is used to determine that IC 4499 has an age of 12 +/- 1 Gyr and a cluster reddening of E(B - V) = 0.22 +/- 0.02. Hence, IC 4499 is coeval with the majority of Galactic globular clusters, in contrast to suggestions of a younger age. The density profile of the cluster is observed to not flatten out to at least r similar to 800 arcsec, implying that either the tidal radius of this cluster is larger than previously estimated, or that IC 4499 is surrounded by a halo. Unlike the situation in some other, more massive, globular clusters, no anomalous colour spreads in the ultraviolet are detected among the red giant branch stars. The small uncertainties in our photometry should allow the detection of such signatures apparently associated with variations of light elements within the cluster, suggesting that IC 4499 consists of a single stellar population.

We present precise optical and near-infrared ground-based photometry of two Globular Clusters (GCs): Omega Cen and 47 Tuc. These photometric catalogs are unbiased in the Red Giant Branch (RGB) region close to the tip. We provide new estimates of the RGB tip (TRGB) magnitudes--m_I(TRGB)=9.84+/-0.05, Omega Cen; m_I(TRGB)=9.46+/-0.06, 47 Tuc--and use these to determine the relative distances of the two GCs. We find that distance ratios based on different calibrations of the TRGB, the RR Lyrae stars and kinematic distances agree with each other within one sigma. Absolute TRGB and RR Lyrae distance moduli agree within 0.10--0.15 mag, while absolute kinematic distance moduli are 0.2--0.3 mag smaller. Absolute distances to 47 Tuc based on the Zero-Age-Horizontal-Branch and on the white dwarf fitting agree within 0.1 mag, but they are 0.1--0.3 mag smaller than TRGB and RR Lyrae distances., 5 pages, 4 figures, accepted for publication by ApJL

We present deep and accurate Near-Infrared (NIR) photometry of the Galactic Globular Cluster (GC) Omega Cen. Data were collected using the Multi-Conjugate Adaptive Optics Demonstrator (MAD) on VLT (ESO). The unprecedented quality of the images provided the opportunity to perform accurate photometry in the central crowded regions. Preliminary results indicate that the spread in age among the different stellar populations in Omega Cen is limited., 6 pages, 3 figures, to appear in the Springer Astrophysics and Space Science Proceedings, "Science with the VLT in the ELT era", ed. A. Moorwood