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SOXS (Son Of X-Shooter) is the new ESO instrument that is going to be installed on the 3.58-m New Technology Telescope at the La Silla Observatory. SOXS is a single object spectrograph offering a wide simultaneous spectral coverage from U- to H-band. Although such an instrument may have potentially a large variety of applications, the consortium designed it with a clear science case: it is going to provide the spectroscopic counterparts to the ongoing and upcoming imaging surveys, becoming one of the main follow-up instruments in the Southern hemisphere for the classification and characterization of transients. The NTT+SOXS system is specialized to observe all transients and variable sources discovered by imaging surveys with a flexible schedule maintained by the consortium, based on a remote scheduler which will interface with the observatory software infrastructure. SOXS is realized timely to be highly synergic with transients discovery machines like the Vera C. Rubin Observatory. The instrument has been integrated and tested in Italy, collecting and assembling subsystems coming from all partners spread over six countries in three continents. The first preparatory activities in Chile have been completed at the telescope. This article gives an updated status of the project before the shipping of the instrument to Chile., Comment: SPIE Astronomical Telescopes + Instrumentation, 2024, Yokohama, Japan

We study the role of galaxy clusters in the mass-metallicity relation by using a sample of galaxies belonging to the AC114 (z=0.317) galaxy cluster. The data was taken from archival VIMOS-MOS spectroscopy to estimate gas-phase metallicities by using strong-line methods. On the other hand, the data obtained from DECaLS DR10 and VIKING DR4 ESO surveys were used to estimate photometric masses. We found that passive galaxies dominate the population of AC114 in the cluster center, whereas the star-forming members tend to be located outside this region. The constructed MZR from the latter indicates that AC114 SF galaxies have a lower metallicity content than foreground galaxies (z up to 0.28) and the same or even lower metallicities with respect to background galaxies (spanning redshifts 0.34 to 0.70), producing slightly a shallower slope compared to the field MZR at z~0.3. Additionally, it shows a higher scatter of 0.17 dex, consistent with MZRs of galaxy clusters reported in the literature. The responsible mechanisms behind the scatter are consistent with simulations and observations where dynamic and environmental effects such as galaxy-galaxy interactions and ram-pressure stripping are shaping the chemical evolution of the AC114 SF members. The former mechanism can decrease gas-phase metallicities because of pristine gas infall to the galaxy's outskirts, and the latter increases gas-phase metallicities because of the stripping of the metal-poor gas located at the outskirts of the SF members. The AC114 SF members are metal-poorer than field galaxies at the same redshift, so the cluster dominated by galaxy-galaxy interactions is the best scenario that explains the slightly shallower slope and the higher scatter of the AC114-MZR compared to the field MZR at z~0.3., Comment: 25 pages, 14 figures, 4 tables

After the second data release of Gaia, the number of new globular cluster candidates has increased importantly. However, most of them need to be properly characterised, both spectroscopically and photometrically, by means of radial velocities, metallicities, and deeper photometric observations. Our goal is to provide an independent confirmation of the cluster nature of Gran 4, a recently discovered globular cluster, with follow-up spectroscopic observations. The derived radial velocity for individual stars, coupled with proper motions, allows us to isolate cluster members from field stars, while the analysis of their spectra allows us to derive metallicities. By including in the analysis the recently confirmed clusters Gran 1, 2, 3, and 5, we aim to completely characterise the sample presented in Gran et al. 2022. Using Gaia DR3 and VVV catalogue data and MUSE@VLT observations, we performed a selection of cluster members based on their proper motions, radial velocities and their position in colour-magnitude diagrams. Furthermore, full spectral synthesis was performed on the cluster members, extracting surface parameters and metallicity from MUSE spectra. Finally, a completeness estimation was performed on the total globular cluster population of the Milky Way. We confirm the nature of Gran 4, a newly discovered globular cluster behind the Galactic bulge, with a mean radial velocity of ${\rm RV} = -265.28 \pm 3.92$ km s$^{-1}$ and a mean metallicity of ${\rm [Fe/H] = -1.72 \pm 0.32}$ dex. Additionally, independent measurements of the metallicities were derived for Gran 1, 2, 3, and 5. We also revise the observational lower mass limit for a globular cluster to survive in the bulge/disk environment. We estimate that $\sim 12-26$ globular clusters have still to be discovered on the other side of the Galaxy (i.e., behind the bulge/bar/disk), up to 20 kpc., Comment: 8 pages, 5 figures, appendix: 5 tables and 1 figure. Accepted for publication for A&A

Globular clusters (GCs) are excellent tracers of the formation and early evolution of the Milky Way. The bulge GCs (BGCs) are particularly important because they can reveal vital information about the oldest, in-situ component of the Milky Way. We aim at deriving mean metallicities and radial velocities for 13 GCs that lie towards the bulge and are generally associated with this component. We use near infrared low resolution spectroscopy with the FORS2 instrument on the VLT to measure the wavelengths and equivalent widths of the CaII triplet (CaT) lines for a number of stars per cluster. We derive radial velocities, ascertain membership and apply known calibrations to determine metallicities for cluster members, for a mean of 11 members per cluster. We derive mean cluster RV values to 3 km/s, and mean metallicities to 0.05 dex. Our sample has metallicities lying between -0.21 and -1.64 and is distributed between the traditional metal-rich BGC peak near [Fe/H] aprox. -0.5 and a more metal-poor peak around [Fe/H] aprox. -1.1, which has recently been identified. These latter are candidates for the oldest GCs in the Galaxy, if blue horizontal branches are present, and include BH 261, NGC 6401, NGC 6540, NGC 6642, and Terzan 9. Finally, Terzan 10 is even more metal-poor. However, dynamically, Terzan 10 is likely an intruder from the halo, possibly associated with the Gaia-Enceladus or Kraken accretion events. Terzan 10 is also confirmed as an Oosterhotype II GC based on our results. The lone halo intruder in our sample, Terzan 10, is conspicuous for also having by far the lowest metallicity, and casts doubt on the possibility of any bonafide BGCs at metallicities below about aprox. -1.5., Comment: 13 pages, 10 figures. Accepted for publication on Astronomy & Astrophysics

SOXS (Son Of X-Shooter) is a single object spectrograph offering a simultaneous spectral coverage from U- to H-band, built by an international consortium for the 3.58-m ESO New Technology Telescope at the La Silla Observatory. It is designed to observe all kind of transients and variable sources discovered by different surveys with a highly flexible schedule maintained by the consortium, based on the Target of Opportunity concept. SOXS is going to be a fundamental spectroscopic partner for any kind of imaging survey, becoming one of the premier transient follow-up instruments in the Southern hemisphere. This paper gives an updated status of the project, when the instrument is in the advanced phase of integration and testing in Europe, prior to the activities in Chile., Comment: Proc. SPIE 12184, Ground-based and Airborne Instrumentation for Astronomy IX, 121840O (2022)

Recent wide-area surveys have enabled us to study the Milky Way with unprecedented detail. Its inner regions, hidden behind dust and gas, have been partially unveiled with the arrival of near-IR photometric and spectroscopic datasets. Among recent discoveries, there is a population of low-mass globular clusters, known to be missing, especially towards the Galactic bulge. In this work, five new low-luminosity globular clusters located towards the bulge area are presented. They were discovered by searching for groups in the multi-dimensional space of coordinates, colours, and proper motions from the Gaia EDR3 catalogue and later confirmed with deeper VVV survey near-IR photometry. The clusters show well-defined red-giant branches and, in some cases, horizontal branches with their members forming a dynamically coherent structure in proper motion space. Four of them were confirmed by spectroscopic follow-up with the MUSE instrument on the ESO VLT. Photometric parameters were derived, and when available, metallicities, radial velocities and orbits were determined. The new clusters Gran 1 and 5 are bulge globular clusters, while Gran 2, 3, and 4 present halo-like properties. Preliminary orbits indicate that Gran 1 might be related to the Main Progenitor, or the so-called ''low-energy'' group, while Gran 2, 3 and 5 appear to follow the Gaia-Enceladus-Sausage. This study demonstrates that the Gaia proper motions, combined with the spectroscopic follow-up and colour-magnitude diagrams, are required to confirm the nature of cluster candidates towards the inner Galaxy. High stellar crowding and differential extinction may hide other low-luminosity clusters., Comment: 15 pages, 11 figures, appendix: 7 figures, accepted for publication in MNRAS. Updated version with the correct orbit transformation applied. Fig. 11 and one sentence in Abstract, one in Sec. 4 and one in Summary were changed

We present a multi-instrument spectroscopic analysis of the unique Li/Na-rich giant star 25664 in Omega Centauri using spectra acquired with FLAMES-GIRAFFE, X-SHOOTER, UVES and HARPS. Li and Na abundances have been derived from the UVES spectrum using transitions weakly sensitive to non-local thermodynamic equilibrium and assumed isotopic ratio. This new analysis confirms the surprising Li and Na abundances of this star (A(Li) =+2.71+-0.07 dex, [Na/Fe]=+1.00+-0.05 dex). Additionally, we provide new pieces of evidence for its chemical characterisation. The 12C/13C isotopic ratio (15+-2) shows that this star has not yet undergone the extra-mixing episode usually associated with the red giant branch bump. Therefore, we can rule out the scenario of efficient deep extra-mixing during the red giant branch phase envisaged to explain the high Li and Na abundances. Also, the star exhibits high abundances of both C and N ([C/Fe]=+0.45+-0.16 dex and [N/Fe]=+0.99+-0.20 dex), not compatible with the typical C-N anticorrelation observed in globular cluster stars. We found evidence of a radial velocity variability in 25664, suggesting that the star could be part of a binary system, likely having accreted material from a more massive companion when the latter was evolving in the AGB phase. Viable candidates for the donor star are AGB stars with 3-4 Msun and super-AGB stars (~7-8 Msun), both able to produce Li- and Na-rich material. Alternatively, the star could be formed from the pure ejecta of a super-AGB stars, before the dilution with primordial gas occurs., Comment: Accepted for publication on A&A

The second phase of the APOGEE survey is providing near-infrared, high-resolution, high signal-to-noise spectra of stars in the halo, disk, bar and bulge of the Milky Way. The near-infrared spectral window is especially important in the study of the Galactic bulge, where stars are obscured by the dust and gas of the disk in its line-of-sight. We present a chemical characterisation of the globular cluster NGC 6544 with high-resolution spectroscopy. The characterisation of the cluster chemical fingerprint, given its status of "interloper" towards the Galactic bulge and clear signatures of tidal disruption in its core is crucial for future chemical tagging efforts. Cluster members were selected from the DR16 of the APOGEE survey, using chemo-dynamical criteria of individual stars. A sample of 23 members of the cluster was selected. An analysis considering the intra-cluster abundance variations, known anticorrelations is given. According to the RGB content of the cluster, the iron content and $\alpha$-enhancement are [Fe/H] $= -1.44 \pm 0.04$ dex and [$\alpha$/Fe] $= 0.20 \pm 0.04$ dex, respectively. Cluster members show a significant spread in [Fe/H] and [Al/Fe] that is larger than expected based on measurement errors. An [Al/Fe] spread, signal of an Mg-Al anticorrelation is observed and used to constraint the cluster mass budget, along with C, N, Mg, Si, K, Ca, and Ce element variations are discussed. Across all the analysed evolutionary stages (RGB and AGB), about $\sim2/3$ (14 out of 23) show distinct chemical patterns, possibly associated with second-generation stars., Comment: 16 pages, 9 figures, MNRAS accepted

We present an update on the sample of soft gamma-ray selected giant radio galaxies (GRGs) extracted from INTEGRAL/IBIS and Swift/BAT surveys; it includes 8 new sources and one candidate object. In the new sample all, but one source, display FR II radio morphologies; the only exception is B21144+35B which is an FR I. The objects belong to both type 1 and 2 AGN optical classes and have redshifts in the range 0.06-0.35, while the radio sizes span from 0.7 to 1 Mpc. In this study, we present for the first time two objects that were never discussed as GRGs before and propose a new candidate GRG. We confirm the correlation between the X-ray luminosity and the radio core luminosity found for other soft gamma-ray selected GRGs and expected for AGNs powered by efficient accretion. We also corroborate previous results that indicate that the luminosity of the radio lobes is relatively low compared with the nuclear X-ray emission. This supports the idea that the nucleus of these GRGs is now more powerful than in the past, consistent with a restarting activity scenario, Comment: 12 pages, 9 figures. Accepted for publication in MNRAS

The nature of a substantial percentage (about one fifth) of hard X-ray sources discovered with the BAT instrument onboard the Neil Gehrels Swift Observatory (hereafter Swift) is unknown because of the lack of an identified longer-wavelength counterpart. Without such follow-up, an X-ray catalogue is of limited astrophysical value: we therefore embarked, since 2009, on a long-term project to uncover the optical properties of sources identified by Swift by using a large suite of ground-based telescopes and instruments. In this work, we continue our programme of characterization of unidentified or poorly studied hard X-ray sources by presenting the results of an optical spectroscopic campaign aimed at pinpointing and classifying the optical counterparts of 35 hard X-ray sources taken from the 70-month BAT catalogue. (...) With the use of optical spectra taken at six different telescopes we were able to identify the main spectral characteristics (continuum type, redshift, and emission or absorption lines) of the observed objects, and determined their nature. We identify and characterize a total of 41 optical candidate counterparts corresponding to 35 hard X-ray sources given that, because of positional uncertainties, multiple lower energy counterparts can sometimes be associated with higher energy detections. We discuss which ones are the actual (or at least most likely) counterparts based on our observational results. In particular, 31 sources in our sample are active galactic nuclei: 16 are classified as Type 1 (with broad and narrow emission lines) and 13 are classified as Type 2 (with narrow emission lines only); two more are BL Lac-type objects. We also identify one LINER, one starburst, and 3 elliptical galaxies. The remaining 5 objects are galactic sources: we identify 4 of them as cataclysmic variables, whereas one is a low mass X-ray binary., Comment: Last draft version before referee's approval. Closest to the final published article

The analysis of the night cloud cover is very important for astronomical observation in real time, considering a typical observation time of about 15 minutes, and to have a statistics of the night cloud cover. In this paper we use the SQM (Sky Quality Meter) for high resolution temporal analysis of the La Silla and Asiago (Ekar observatory) sky: 3 and 5 minutes respectively. We investigate the annual temporal evolution of the natural contributions of the sky in a site not influenced by artificial light at night (ALAN) and one highly influenced respectively. We also make a correlation between GOES and AQUA satellites data and ground-based SQM data to confirm a relationship between the SQM data and cloud cover. We develop an algorithm that allows the use of the SQM for night cloud detection and we reach a correlation of 97.2\% at La Silla and 94.6\% at Asiago with the nighttime cloud cover detected by the GOES and AQUA satellites. Our algorithm also classifies the photometric (PN) and spectroscopic nights (SN). We measure 59.1\% PN and 21.7\% SN for a total percentage of clear nights of 80.8\% at La Silla in 2018. The respective Ekar observatory values are 31.1\% PN, 24.0\% SN and 55.1\% of total clear nights time. Application to the SQM network would involve the development of long-term statistics and big data forecasting models, for site testing and real-time astronomical observation.

In this article, we present a detailed chemical analysis of seven red giant members of NGC 6553 using high-resolution spectroscopy from VLT FLAMES. We obtained the stellar parameters (Teff, Log(g), vt, [Fe/H]) of these stars from the spectra, and we measured the chemical abundance for 20 elements, including light elements, iron-peak elements, alpha-elements and neutron-capture elements. The metallicities in our sample stars are consistent with a homogeneous distribution. We found a mean of [Fe/H]=-0.14+/-0.07 dex, in agreement with other studies. Using the alpha-elements Mg, Si, Ca and Ti we obtain the mean of [alpha/Fe]=0.11+/-0.05. We found a vertical relation between Na and O, characterized by a significant spread in Na and an almost non-existent spread in O. In fact, Na and Al are the only two light elements with a large intrinsic spread, which demonstrates the presence of Multiple Populations (MPs). An intrinsic spread in Mg is not detected in this study. The alpha, iron-peak and neutron capture elements show good agreement with the trend of the bulge field stars, indicating similar origin and evolution, in concordance with our previous studies for two other bulge GCs (NGC 6440 and NGC 6528)., Comment: 12 pages, 11 figures, 4 tables. Accepted for publication in MNRAS

The object ESO456-SC38 (Djorgovski 2) is one of the globular clusters that is closest to the Galactic center. It is on the blue horizontal branch and has a moderate metallicity of [Fe/H]~-1.0. It is thus similar to the very old inner bulge globular clusters NGC 6522, NGC 6558, and HP 1, and therefore appears to be part of the primeval formation stages of the Milky Way. The aim of this work is to determine an accurate distance and metallicity for ESO456-SC38, as well as orbital parameters, in order to check similarities with other clusters in the inner bulge that have previously been well studied in terms of spectroscopy and photometry. This is a considerably fainter cluster that is contaminated by a rich stellar field; it is also quite absorbed by the dusty foreground. We analyzed ESO456-SC38 based on Hubble Space Telescope photometry, with the filters F606W from ACS, F110W and F160W from WFC3,and photometry in V and I from FORS2 at the VLT. We combined this with identified stars that are covered by Gaia Data Release 2. The isochrone fitting was carried out with the statistical Markov chain Monte Carlo method. We derive an accurate distance of dSun = 8.75+-0.12 kpc and a reddening of E(B-V)=0.81^+0.02_-0.02. The best-fitting BaSTI isochrones correspond to an age of 12.70^{+0.72}_{-0.69} Gyr and a metallicity of [Fe/H]=-1.11^{+0.03}_{-0.03}. ESO 456-SC38 adds to the list of moderately metal-poor globular clusters located in the inner bulge. It is on the blue horizontal branch and is very old. The cluster is confined to the bulge and bar region, but it does not support the Galactic bar structure. The old stellar population represented by clusters like this has to be taken into account in models of Galactic bulge formation. Studying them also provides indications on the formation times of the globular clusters themselves., Comment: Astronomy & Astrophysics, in press (accepted: 17-06-2019)

NGC 6558 is a bulge globular cluster with a blue horizontal branch (BHB), combined with a metallicity of [Fe/H]~-1.0. It is similar to HP 1 and NGC 6522, which could be among the oldest objects in the Galaxy. Element abundances in these clusters could reveal the nature of the first supernovae. We aim to carry out detailed spectroscopic analysis for four red giants of NGC 6558, in order to derive the abundances of the light elements C, N, O, Na, Al, the alpha-elements Mg, Si, Ca, Ti, and the heavy elements Y, Ba, and Eu. High-resolution spectra of four stars with FLAMES-UVES@VLT UT2-Kueyen were analysed. Spectroscopic parameter-derivation was based on excitation and ionization equilibrium of FeI and FeII. This analysis results in a metallicity of [Fe/H] = -1.17+-0.10 for NGC 6558. We find the expected alpha-element enhancements in O and Mg with [O/Fe]=+0.40, [Mg/Fe]=+0.33, and low enhancements in Si and Ca. Ti has a moderate enhancement of [Ti/Fe]=+0.22. The r-element Eu appears very enhanced with a mean value of [Eu/Fe]=+0.63. Ba appears to have a solar abundance ratio relative to Fe. NGC 6558 shows an abundance pattern that could be typical of the oldest inner bulge globular clusters, together with the pattern in the similar clusters NGC 6522 and HP 1. They show low abundances of the odd-Z elements Na and Al, and of the explosive nucleosynthesis alpha-elements Si, Ca, and Ti. The hydrostatic burning alpha-elements O and Mg are normally enhanced as expected in old stars enriched with yields from core-collapse supernovae, and the iron-peak elements Mn, Cu, Zn show low abundances, which is expected for Mn and Cu, but not for Zn. Finally, the cluster trio NGC 6558, NGC 6522, and HP 1 show similar abundance patterns., Comment: Astronomy & Astrophysics, in press, 14 pages, 12 figures

The Bulge Globular Clusters (GCs) are key tracers of this central ancient component of our Galaxy. It is essential to understand their formation and evolution to study that of the bulge, as well as their relationship with the other Galactic GC systems (halo and disk GCs). Our main goals are to obtain detailed abundances for a sample of seven red giant members of NGC 6528 in order to characterize its chemical composition and study the relationship of this GC with the bulge, and with other bulge, halo and disk GCs. Moreover, we analyze this cluster$'$s behavior associated with the Multiple Populations (MPs) phenomenon. We obtained the stellar parameters and chemical abundances of light elements (Na, Al), iron-peak elements (V, Cr, Mn, Fe, Co, Ni, Cu), {\alpha}-elements (O, Mg, Si, Ca, Ti) and heavy elements (Zr, Ba, Eu) in seven red giant members of NGC 6528 using high resolution spectroscopy from FLAMES-UVES. We obtained in six stars of our sample a mean iron content of [Fe/H]=-0.14+/-0.03 dex, in good agreement with other studies. We found no significant internal iron spread. We detected one candidate variable star, which was excluded from the mean in iron content, we derived a metallicity in this star of [Fe/H]=-0.55+/-0.04 dex. Moreover, we found no extended O-Na anticorrelation but instead only an intrinsic Na spread. In addition, NGC 6528 does not exhibit a Mg-Al anticorrelation, and no significant spread in either Mg or Al. The {\alpha} and iron-peak elements show good agreement with the bulge field star trend. The heavy elements are slightly dominated by the r-process. The chemical analysis suggests an origin and evolution similar to that of typical old Bulge field stars. Finally, we find remarkable agreement in the chemical patterns of NGC 6528 and another bulge GC, NGC 6553, suggesting a similar origin and evolution., Comment: Accepted for publication in A&A. 12 pages, 13 figures, 4 tables

Although the globular clusters in the Milky Way have been studied for a long time, a significant fraction of them lack homogeneous metallicity and radial velocity measurements. In an earlier paper we presented the first part of a project to obtain metallicities and radial velocities of Galactic globular clusters from multiobject spectroscopy of their member stars using the ESO Very Large Telescope. In this paper we add metallicities and radial velocities for a new sample of 28 globular clusters, including in particular globular clusters in the MW halo and the Galactic bulge. Together with our previous results, this study brings the number of globular clusters with homogeneous measurements to $\sim 69$ \% of those listed in the W. Harris' catalogue. As in our previous work, we have used the CaII triplet lines to derive metallicities and radial velocities. For most of the clusters in this study, this is the first analysis based on spectroscopy of individual member stars. The metallicities derived from the CaII triplet are then compared to the results of our parallel study based on spectral fitting in the optical region and the implications for different calibrations of the CaII triplet line strengths are discussed. We also comment on some interesting clusters and investigate the presence of an abundance spread in the globular clusters here. A hint of a possible intrinsic spread is found for NGC 6256, which therefore appears to be a good candidate for further study., Comment: 13 pages, 9 figures, accepted for publication in Astronomy and Astrophysics

PBC J2333.9-2343 is a peculiar active nucleus with two giant radio lobes and a weak blazar-like nucleus at their center. In the present work we show new optical, UV, and X-ray data taken from the San Pedro M\'artir telescope, the New Technology Telescope, NTT/EFOSC2, and the Swift/XRT satellite. The source is highly variable at all frequencies, in particular the strongest variations are found in the broad H$\alpha$ component with a flux increase of 61$\pm$4 per cent between 2009 and 2016, following the X-ray flux increase of 62$\pm$6 per cent between 2010 and 2016. We also detected a broad H$\beta$ component in 2016, making the optical classification change from type 1.9 to type 1.8 in one year. We have also detected a broad component of the [OIII]$\lambda$5007 line, which is blue-shifted and of high velocity, suggesting an origin from a highly disturbed medium, possibly an outflow. The line flux variability and broad widths are indicative of a jet that is, at least in part, responsible for the ionization of the BLR and NLR., Comment: 7 pages, 2 figures, accepted for publication in MNRAS

We have analysed 10 high resolution spectra of Type II Cepheids with periods less than 3 days. We find that they clearly separate into two groups: those with near or slightly below solar metallicities, and those with [Fe/H] between --1.5 and --2.0. While the former are usually called BL~Her stars, we suggest that the latter be called UY~Eri stars. The UY~Eri subclass appears to be similar to the short period variables in globular clusters of the Galactic Halo. Globular clusters with [Fe/H] $\textgreater$ --1.0 almost never have Type II Cepheids.

We present the first spectroscopic abundance determination of iron, alpha-elements (Si, Ca and Ti) and sodium for the Mira variable V1 in the metal-rich globular cluster NGC 5927. We use high-resolution (R~ 28,000), high signal-to-noise ratio (~200) spectra collected with WINERED, a near-infrared (NIR) spectrograph covering simultaneously the wavelength range 0.91--1.35 micron. The effective temperature and the surface gravity at the pulsation phase of the spectroscopic observation were estimated using both optical (V) and NIR time-series photometric data. We found that the Mira is metal-rich ([Fe/H]=-0.55 \pm 0.15) and moderately alpha-enhanced ([alpha/Fe]=0.15 \pm 0.01, sigma=0.2). These values agree quite well with the mean cluster abundances based on high-resolution optical spectra of several cluster red giants available in the literature ([Fe/H]=-0.47 \pm 0.06, [alpha/Fe]=+0.24 \pm 0.05). We also found a Na abundance of +0.35 \pm 0.20 that is higher than the mean cluster abundance based on optical spectra (+0.18 \pm 0.13). However, the lack of similar spectra for cluster red giants and that of corrections for departures from local-thermodynamical equilibrium prevents us from establishing whether the difference is intrinsic or connected with multiple populations. These findings indicate a strong similarity between optical and NIR metallicity scales in spite of the difference in the experimental equipment, data analysis and in the adopted spectroscopic diagnostics., Comment: Accepted for publication in the Astrophysical Journal Letters, 9 pages, 3 figures

We observed 6 He-clump stars of the intermediate-age stellar cluster Gaia1 with the MIKE/MAGELLAN spectrograph. A possible extra-galactic origin of this cluster, recently discovered thanks to the first data release of the ESA Gaia mission, has been suggested, based on its orbital parameters. Abundances for Fe, alpha, proton- and neutron-capture elements have been obtained. We find no evidence of intrinsic abundance spreads. The iron abundance is solar ([FeI/H]=+0.00 +-0.01; sigma = 0.03 dex). All the other abundance ratios are, by and large, solar-scaled, similar to the Galactic thin disk and open clusters stars of similar metallicity. The chemical composition of Gaia1 does not support an extra-galactic origin for this stellar cluster, that can be considered as a standard Galactic open cluster., Comment: Accepted for publication to A&A Letter

Context. Galactic Globular Clusters (GCs) are essential tools to understand the earliest epoch of the Milky Way, since they are among the oldest objects in the Universe and can be used to trace its formation and evolution. Current studies using high resolution spectroscopy for many stars in each of a large sample of GCs allow us to develop a detailed observational picture about their formation and their relation with the Galaxy. However, it is necessary to complete this picture by including GCs that belong to all major Galactic components, including the Bulge. Aims. Our aim is to perform a detailed chemical analyses of the bulge GC NGC 6440 in order to determine if this object has Multiple Populations (MPs) and investigate its relation with the Bulge of the Milky Way and with the other Galactic GCs, especially those associated with the Bulge, which are largely poorly studied. Methods. We determined the stellar parameters and the chemical abundances of light elements (Na, Al), iron-peak elements (Fe, Sc, Mn, Co, Ni), $\alpha$-elements (O, Mg, Si, Ca, Ti) and heavy elements (Ba, Eu) in seven red giant members of NGC 6440 using high resolution spectroscopy from FLAMES@UVES. Results. We found a mean iron content of [Fe/H]=-0.50$\pm$0.03 dex in agreement with other studies. We found no internal iron spread. On the other hand, Na and Al show a significant intrinsic spread, but the cluster has no significant O-Na anticorrelation nor exhibits a Mg-Al anticorrelation. The $\alpha$-elements show good agreement with the Bulge field star trend, although they are at the high alpha end and are also higher than those of other GCs of comparable metallicity. The heavy elements are dominated by the r-process, indicating a strong contribution by SNeII. The chemical analysis suggests an origin similar to that of the Bulge field stars., Comment: 12 pages, 13 figures, Accepted for publication in A&A

The globular cluster HP~1 is projected at only 3.33 degrees from the Galactic center. Together with its distance, this makes it one of the most central globular clusters in the Milky Way. It has a blue horizontal branch (BHB) and a metallicity of [Fe/H]~-1.0. This means that it probably is one of the oldest objects in the Galaxy. Abundance ratios can reveal the nucleosynthesis pattern of the first stars as well as the early chemical enrichment and early formation of stellar populations. High-resolution spectra obtained for six stars were analyzed to derive the abundances of the light elements C, N, O, Na, and Al, the alpha-elements Mg, Si, Ca, and Ti, and the heavy elements Sr, Y , Zr, Ba, La, and Eu.} High-resolution spectra of six red giants that are confirmed members of the bulge globular cluster HP~1 were obtained with the 8m VLT UT2-Kueyen telescope with the UVES spectrograph in FLAMES-UVES configuration. The spectroscopic parameter derivation was based on the excitation and ionization equilibrium of FeI and FeII. We confirm a mean metallicity of [Fe/H] = -1.06~0.10, by adding the two stars that were previously analyzed in HP~1. The alpha-elements O and Mg are enhanced by about +0.3<[O,Mg/Fe]<+0.5 dex, Si is moderately enhanced with +0.15<[Si/Fe]<+0.35dex, while Ca and Ti show lower values of -0.04<[Ca,Ti/Fe]<+0.28dex. The r-element Eu is also enhanced with [Eu/Fe]~+0.4, which together with O and Mg is indicative of early enrichment by type II supernovae. Na and Al are low, but it is unclear if Na-O are anticorrelated. The heavy elements are moderately enhanced, with -0.20<[La/Fe]<+0.43dex and 0.0<[Ba/Fe]<+0.75~dex, which is compatible with r-process formation. The spread in Y, Zr, Ba, and La abundances, on the other hand, appears to be compatible with the spinstar scenario or other additional mechanisms such as the weak r-process., Comment: 15 pages, 8 figures In press in Astronomy & Astrophysics (2016)

The old and metal rich open cluster NGC 6253 was observed with the FLAMES multi-object spectrograph during an extensive radial velocity campaign monitoring 317 stars with a median of 15 epochs per object. All the targeted stars are located along the upper main sequence of the cluster between 14.8 $<$ V $<$ 16.5. Fifty nine stars are confirmed cluster members both by radial velocities and proper motions and do not show evidence of variability. We detected 45 variable stars among which 25 belong to NGC 6253. We were able to derive an orbital solution for 4 cluster members (and for 2 field stars) yielding minimum masses in between $\sim$90 M$\rm_J$ and $\sim$460 M$\rm_J$ and periods between 3 and 220 days. Simulations demonstrated that this survey was sensitive to objects down to 30 M$\rm_J$ at 10 days orbital periods with a detection efficiency equal to 50%. On the basis of these results we concluded that the observed frequency of binaries down to the hydrogen burning limit and up to 20 days orbital period is around (1.5$\pm$1.3)% in NGC 6253. The overall observed frequency of binaries around the sample of cluster stars is (13$\pm$3)%. The median radial velocity precision achieved by the GIRAFFE spectrograph in this magnitude range was around $\sim$240m$\rm\,s^{-1}$ ($\sim$180 m$\rm\,s^{-1}$ for UVES). Based on a limited follow-up analysis of 7 stars in our sample with the HARPS spectrograph we determined that a precision of 35 m $\rm s^{-1}$ can be reached in this magnitude range, offering the possibility to further extend the variability analysis into the substellar domain. Prospects are even more favourable once considering the upcoming ESPRESSO spectrograph at VLT., Comment: Accepted by MNRAS

We present a new calibration of the Calcium II Triplet equivalent widths versus [Fe/H], constructed upon K giant stars in the Galactic bulge. This calibration will be used to derive iron abundances for the targets of the GIBS survey, and in general it is especially suited for solar and supersolar metallicity giants, typical of external massive galaxies. About 150 bulge K giants were observed with the GIRAFFE spectrograph at VLT, both at resolution R~20,000 and at R~6,000. In the first case, the spectra allowed us to perform direct determination of Fe abundances from several unblended Fe lines, deriving what we call here high resolution [Fe/H] measurements. The low resolution spectra allowed us to measure equivalent widths of the two strongest lines of the near infrared Calcium II triplet at 8542 and 8662 A. By comparing the two measurements we derived a relation between Calcium equivalent widths and [Fe/H] that is linear over the metallicity range probed here, -1<[Fe/H]<+0.7. By adding a small second order correction, based on literature globular cluster data, we derived the unique calibration equation [Fe/H]$_{CaT} = -3.150 + 0.432W' + 0.006W'^2$, with a rms dispersion of 0.197 dex, valid across the whole metallicity range -2.3<[Fe/H]<+0.7., Comment: Accepted for publication in A&A

A robust classification of Cepheids into their different sub-classes and, in particular, between classical and Type II Cepheids, is necessary to properly calibrate the period-luminosity relations and for populations studies in the Galactic disc. Type II Cepheids are, however, very diverse, and classifications based either on intrinsic (period, light curve) or external parameters (e.g., [Fe/H], |z|) do not provide a unique classification. We want to ascertain the classification of two Cepheids, HQ Car and DD Vel, that are sometimes classified as classical Cepheids and sometimes as Type II Cepheids. To achieve this goal, we examine both their chemical composition and the presence of specific features in their spectra. We find emission features in the H{\alpha} and in the 5875.64 {\AA} He I lines that are typical of W Vir stars. The [Na/Fe] (or [Na/Zn]) abundances are typical of thick-disc stars, while BL Her stars are Na-overabundant ([Na/Fe]>+0.5 dex). Finally, the two Cepheids show a possible (HQ Car) or probable (DD Vel) signature of mild dust-gas separation that is usually observed only in long-period type II Cepheids and RV Tau stars. These findings clearly indicate that HQ Car and DD Vel are both Type II Cepheids from the W Vir sub-class. Several studies have reported an increase in the Cepheids' abundance dispersion towards the outer (thin) disc. A detailed inspection of the Cepheid classification, in particular for those located in the outer disc, will indicate whether this feature is real or simply an artefact of the inclusion of type II Cepheids belonging to the thick disc in the current samples., Comment: 11 pages, 8 figures, accepted in A&A

The severe crowding towards the Galactic plane suggests that the census of nearby stars in that direction may be incomplete. Recently, Scholz reported a new M9 object at an estimated distance d~7 pc (WISE J072003.20-084651.2; hereafter WISE0720) at Galactic latitude b=2.3 degr. Our goals are to determine the physical characteristics of WISE0720, its kinematic properties, and to address the question if it is a binary object, as suggested in the discovery paper. Optical and infrared spectroscopy from the Southern African Large Telescope and Magellan, respectively, and spectral energy distribution fitting were used to determine the spectral type of WISE0720. The measured radial velocity, proper motion and parallax yielded its Galactic velocities. We also investigated if WISE0720 may show X-ray activity based on archival data. Our spectra are consistent with spectral type L0+/-1. We find no evidence for binarity, apart for a minor 2-sigma level difference in the radial velocities taken at two different epochs. The spatial velocity of WISE0720 does not connect it to any known moving group, instead it places the object with high probability in the old thin disk or in the thick disk. The spectral energy distribution fit hints at excess in the 12 and 22 micron WISE bands which may be due to a redder companion, but the same excess is visible in other late type objects, and it more likely implies a shortcoming of the models (e.g., issues with the effective wavelengths of the filters for these extremely cool objects, etc.) rather than a disk or redder companion. The optical spectrum shows some Halpha emission, indicative of stellar activity. Archival X-ray observations yield no detection., Comment: A&A, accepted; 9 pages, 6 figures

Using two HST/ACS data-sets that are separated by ~2 years has allowed us to derive the relative proper-motion for the Sagittarius dwarf irregular (SagDIG) and reduce the heavy foreground Galactic contamination. The proper-motion decontaminated SagDIG catalog provides a much clearer view of the young red-supergiant and intermediate-age asymptotic giant branch populations. We report the identification of 3 Milky Way carbon-rich dwarf stars, probably belonging to the thin disk, and pointing to the high incidence of this class at low Galactic latitudes. A sub-group of 4 oxygen-rich candidate stars depicts a faint, red extension of the well-defined SagDIG carbon-rich sequence. The origin of these oxygen-rich candidate stars remains unclear, reflecting the uncertainty in the ratio of carbon/oxygen rich stars. SagDIG is also a gas-rich galaxy characterized by a single large cavity in the gas disk (HI-hole), which is offset by ~360 pc from the optical centre of the galaxy. We nonetheless investigate the stellar feedback hypothesis by comparing the proper-motion cleaned stellar populations within the HI-hole with appropriately selected comparison regions, having higher HI densities external to the hole. The comparison shows no significant differences. In particular, the centre of the HI-hole (and the comparison regions) lack stellar populations younger than ~400 Myr, which are otherwise abundant in the inner body of the galaxy. We conclude that there is no convincing evidence that the SagDIG HI-hole is the result of stellar feedback, and that gravitational and thermal instabilities in the gas are the most likely mechanism for its formation., Comment: Accepted for publication in A&A, 11 pages, 6 jpeg figures

Context. [...] One of the most efficient methods is the measurement of the equivalent width (EW) of the Calcium II Triplet (CaT), corrected for the luminosity and temperature effects via magnitude differences from the horizontal branch (HB). Methods. We use the Ks magnitude difference between the star and the reddest part of the HB (RHB) to generate reduced equivalent widths (rEW) from the datasets presented in Saviane et al. (2012) and Rutledge et al. (1997). Subsequently we calibrated these rEW against three different metellicity (met) scales: the one presented in Carretta et al. (2009), the met values given in Harris (2010) and a version of the former corrected via high-resolution spectroscopic met. Results. We calculated the calibration relations for the two datasets and the three met scales and found that they are approximately equivalent, with differences almost negligible. We compared our nIR calibrations with the corresponding optical ones, and found them to be equivalent, establishing that the luminosity-corrected rEW using the Ks magnitude is compatible with the one obtained from the V magnitude. We then used the met obtained from the calibration to investigate the internal met distributions of the GCs. Conclusions. We have established that the ([Fe/H]:rEW) relation is independent from the mag used for the luminosity correction and find that the calibration relations only change slightly for different met scales. The CaT technique using NIR photometry is thus a powerful tool to derive met. In particular, it can be used to study the internal met spread of a GC. We confirm the presence of at least two met populations in NGC 6656 and find that several other GCs present peculiar met distributions., Comment: 41 pages, 8 tables, 42 figures A&A: recommended publication after revision

We present a detailed study of the strengths of the calcium triplet absorption lines in the spectra of a large sample of red giant members of the luminous outer Galactic halo globular cluster NGC 5824. The spectra were obtained with the FORS2 and GMOS-S multi-object spectrographs at the VLT and the Gemini-S telescope, respectively. By comparing the line strengths of the NGC 5824 stars with those for red giants in clusters with well established abundances, we conclude that there is an intrinsic abundance dispersion in NGC 5824 characterized by an inter-quartile range in [Fe/H] of 0.10 dex and a total range of ~0.3 dex. As for omega-Cen and M22, the abundance distribution shows a steep rise on the metal-poor side and a shallower decline on the metal-rich side. There is also some indication that the distribution is not unimodal with perhaps 3 distinct abundance groupings present. NGC 5824 has a further unusual characteristic: the outer surface density profile shows no signs of a tidal cutoff. Instead the profile has a power-law distribution with cluster stars detected to a radius exceeding 400 pc. We postulate that NGC 5824 may be the remnant nuclear star cluster of a now disrupted dwarf galaxy accreted during the formation of the Galaxy's halo. We further speculate that the presence of an intrinsic [Fe/H] spread is the characteristic that distinguishes former nuclear star clusters from other globular clusters., Comment: 15 pages, 14 figures, accepted for publication in MNRAS

We present deep CMDs for two Subaru Suprime-Cam fields in the Virgo Stellar Stream(VSS)/Virgo Overdensity(VOD) and compare them to a field centred on the highest concentration of Sagittarius (Sgr) Tidal Stream stars in the leading arm, Branch A of the bifurcation. A prominent population of MS stars is detected in all three fields and can be traced as faint as g~24 mag. Using theoretical isochrone fitting we derive an age of 9.1(+1.0;-1.1)Gyr, a median abundance of [Fe/H]=-0.70 (+0.15; -0.20)dex and d_helio of 30.9+-3.0kpc for the MS of the Sgr Stream Branch A. The dominant main sequence populations in the two VSS/VOD fields (Lsun ~265 deg, Bsun ~13 deg) are located at a mean distance of 23.3+-1.6kpc and have an age ~8.2Gyr and an abundance [Fe/H]=-0.67(+0.16;-0.12)dex similar to the Sgr Stream stars. These parameters are also in good agreement with the age of the main population in the Sagittarius dwarf (8.0+-1.5Gyr). They also agree with the peak in the metallicity distribution of 2-3Gyr old M-giants, [Fe/H] ~ -0.6dex, in the Sgr leading arm north. We then compare the results from the VSS/VOD fields with the Sgr Tidal Stream model by Law & Majewski based on a triaxial Galactic halo that is calibrated with SDSS Sgr A-branch and 2MASS M-giant stars. We find that the most prominent feature in the CMDs, the MS population at 23kpc, is not explained by the model. Instead the model predicts in these directions a low density filamentary structure of Sgr debris stars at ~9kpc and a slightly higher concentration of Sgr stars spread from 42-53kpc. At best there is only marginal evidence for the presence of these populations in our data. Our findings then suggest that while there are probably some Sgr debris stars present, the dominant stellar population in the VOD originates from a different halo structure that has almost identical age and metallicity as some sections of the Sgr tidal stream., Comment: 11 pages, 8 figures, 5 tables, accepted for publication in ApJ

We present a study of SN 2009js in NGC 918. Multi-band Kanata optical photometry covering the first ~120 days show the source to be a Type IIP SN. Reddening is dominated by that due to our Galaxy. One-year-post-explosion photometry with the NTT, and a Subaru optical spectrum 16 days post-discovery, both imply a good match with the well-studied subluminous SN 2005cs. The plateau phase luminosity of SN 2009js and its plateau duration are more similar to the intermediate luminosity IIP SN 2008in. Thus, SN 2009js shares characteristics with both subluminous and intermediate luminosity SNe. Its radioactive tail luminosity lies between SN 2005cs and SN 2008in, whereas its quasi-bolometric luminosity decline from peak to plateau (quantified by a newly-defined parameter Delta[logL] measuring adiabatic cooling following shock breakout) is much smaller than both the others. We estimate the ejected mass of 56Ni to be low (~0.007 Msun). The SN explosion energy appears to have been small, similar to SN 2005cs. SN 2009js is the first subluminous SN IIP to be studied in the mid-infrared. It was serendipitously caught by Spitzer at very early times. In addition, it was detected by WISE 105 days later with a significant 4.6 micron flux excess above the photosphere. The infrared excess luminosity relative to the photosphere is clearly smaller than that of SN 2004dj extensively studied in the mid-infrared. The excess may be tentatively assigned to heated dust with mass ~3e-5 Msun, or to CO fundamental emission as a precursor to dust formation., Comment: Accepted for publication in ApJ

The association of Type Ic SNe with long-duration GRBs is well established. We endeavor, through accurate ground-based observational campaigns, to characterize these SNe at increasingly high redshifts. We obtained a series of optical photometric and spectroscopic observations of the Type Ic SN2012bz associated with the Swift long-duration GRB120422A (z=0.283) using the 3.6-m TNG and the 8.2-m VLT telescopes. The peak times of the light curves of SN2012bz in various optical filters differ, with the B-band and i'-band light curves reaching maximum at ~9 and ~23 rest-frame days, respectively. The bolometric light curve has been derived from individual bands photometric measurements, but no correction for the unknown contribution in the near-infrared (probably around 10-15%) has been applied. Therefore, the present light curve should be considered as a lower limit to the actual UV-optical-IR bolometric light curve. This pseudo-bolometric curve reaches its maximum (Mbol = -18.56 +/- 0.06) at 13 +/- 1 rest-frame days; it is similar in shape and luminosity to the bolometric light curves of the SNe associated with z<0.2 GRBs and more luminous than those of SNe associated with XRFs. A comparison with the model generated for the bolometric light curve of SN2003dh suggests that SN2012bz produced only about 15% less 56Ni than SN2003dh, about 0.35 Msol. Similarly the VLT spectra of SN2012bz, after correction for Galactic extinction and for the contribution of the host galaxy, suggest comparable explosion parameters with those observed in SN2003dh (EK~3.5 x 10^52 erg, Mej~7 Msol) and a similar progenitor mass (~25-40 Msol). GRB120422A is consistent with the Epeak-Eiso and the EX,iso-Egamma,iso-E_peak relations. GRB120422A/SN2012bz shows the GRB-SN connection at the highest redshift so far accurately monitored both photometrically and spectroscopically., Comment: 7 pages, 6 figures, 2 tables, accepted for publication in Astronomy & Astrophysics

The ESO Public Survey VISTA Variables in the Via Lactea (VVV) started in 2010. VVV targets 562 sq. deg in the Galactic bulge and an adjacent plane region and is expected to run for ~5 years. In this paper we describe the progress of the survey observations in the first observing season, the observing strategy and quality of the data obtained. The observations are carried out on the 4-m VISTA telescope in the ZYJHKs filters. In addition to the multi-band imaging the variability monitoring campaign in the Ks filter has started. Data reduction is carried out using the pipeline at the Cambridge Astronomical Survey Unit. The photometric and astrometric calibration is performed via the numerous 2MASS sources observed in each pointing. The first data release contains the aperture photometry and astrometric catalogues for 348 individual pointings in the ZYJHKs filters taken in the 2010 observing season. The typical image quality is ~0.9-1.0". The stringent photometric and image quality requirements of the survey are satisfied in 100% of the JHKs images in the disk area and 90% of the JHKs images in the bulge area. The completeness in the Z and Y images is 84% in the disk, and 40% in the bulge. The first season catalogues contain 1.28x10^8 stellar sources in the bulge and 1.68x10^8 in the disk area detected in at least one of the photometric bands. The combined, multi-band catalogues contain more than 1.63x10^8 stellar sources. About 10% of these are double detections due to overlapping adjacent pointings. These overlapping multiple detections are used to characterise the quality of the data. The images in the JHKs bands extend typically ~4 mag deeper than 2MASS. The magnitude limit and photometric quality depend strongly on crowding in the inner Galactic regions. The astrometry for Ks=15-18 mag has rms ~35-175 mas., Comment: Accepted for publication in Astronomy and Astrophysics (Section 14: Catalogs and data)

There is an ongoing debate regarding the onset luminosity of dusty mass loss in population-II red giant stars. In this paper we present VISIR@VLT MIR 8.6 micron imaging of 47Tuc, centre of attention of a number of space-based Spitzer observations and studies. The VISIR high resolution (diffraction limited) observations allow excellent matching to existing optical Hubble space telescope catalogues. The optical-MIR coverage of the inner 1.15 arcmin of the cluster provide the cleanest possible, blending-free, sampling of the upper 3 magnitudes of the giant branch. Our diagrams show no evidence of faint giants with MIR-excess. A combined NIR-MIR diagram further confirms the near absence of dusty red giants. Dusty red giants and asymptotic giant stars are confined to the 47Tuc long period variables population. In particular, dusty red giants are limited to the upper one 8.6 micron magnitude below the giant branch tip. This particular luminosity level corresponds to ~1000 solar luminosity, suggested in previous determinations to mark the onset of dusty mass-loss. Interestingly, at this luminosity level, we detect a small deviation between the colours of red giants and the theoretical isochrones., Comment: Accepted for publication in A&A

Context. Palomar\,1 is a peculiar globular cluster (GC). It is the youngest Galactic GC and it has been tentatively associated to several of the substructures recently discovered in the Milky Way (MW), including the Canis Major (CMa) overdensity and the Galactic Anticenter Stellar Structure (GASS). Aims. In order to provide further insights into its origin, we present the first high resolution chemical abundance analysis for one red giant in Pal\,1. Methods. We obtained high resolution (R=30000) spectra for one red giant star in Pal\,1 using the High Dispersion Spectrograph (HDS) mounted at the SUBARU telescope. We used ATLAS-9 model atmospheres coupled with the SYNTHE and WIDTH calculation codes to derive chemical abundances from the measured line equivalent widths of 18 among $\alpha$, Iron-peak, light and heavy elements. Results. The Palomar~1 chemical pattern is broadly compatible to that of the MW open clusters population and similar to disk stars. It is, instead, remarkably different from that of the Sagittarius (Sgr) dwarf spheroidal galaxy. Conclusions. If Pal\,1 association with either CMa or GASS will be confirmed, this will imply that these systems had a chemical evolution similar to that of the Galactic disk., Comment: 13 pages, 9 figures, 5 tables. Accepted for publication in Astronomy and Astrophysics. Minor changes in the text

Based on previous spectral and temporal optical studies, Q2122-444 has been classified as a naked AGN or true type 2 AGN, that is, an AGN that genuinely lacks a broad line region (BLR). Its optical spectrum seemed to possess only narrow forbidden emission lines that are typical of type 2 (obscured) AGNs, but the long-term optical light curve, obtained from a monitoring campaign over more than two decades, showed strong variability, apparently ruling out the presence of heavy obscuration. Here, we present the results from a ~40 ks XMM-Newton observation of Q2122-444 carried out to shed light on the energetics of this enigmatic AGN. The X-ray analysis was complemented with ATCA radio data to assess the possible presence of a jet, and with new NTT/EFOSC2 optical spectroscopic data to verify the actual absence of a BLR. The higher-quality optical data revealed the presence of strong and broad Balmer lines that are at odds with the previous spectral classification of this AGN. The lack of detection of radio emission rules out the presence of a jet. The X-ray data combined with simultaneous UV observations carried out by the OM aboard XMM-Newton confirm that Q2122-444 is a typical type-1 AGN without any significant intrinsic absorption. New estimates of the black hole mass independently obtained from the broad Balmer lines and from a new scaling technique based on X-ray spectral data suggest that Q2122-444 is accreting at a relatively high rate in Eddington units., Comment: 8 pages, 4 figures, 1 table, accepted for publication in ApJ

IRAS04325+2402 (herafter IRAS04325) is a complex protostellar system hosting two young stellar objects (AB and C in the following) at a separation of 1250AU. Here we present new deep Gemini imaging and spectroscopy for the system covering the wavelength regime from 1-12mu as well as Sub-Millimeter Array interferometry at 870mu, in combination with Spitzer and literature data. Object AB is a low-mass star with a disk/envelope system and an outflow cavity, which is prominently seen in infrared images. Object C, previously suspected to be a brown dwarf, is likely a very low mass star, with an effective temperature of ~3400K. It features an edge-on disk and an elongated envelope, and shows strong indications for accretion and ejection activity. Both objects are likely to drive parsec-scale molecular outflows. The two objects are embedded in an isolated, dense molecular cloud core. High extinction, lack of X-ray emission, and relatively high bolometric luminosity argue for a very young age below 1Myr. The disk/outflow systems of AB and C are misaligned by ~60deg against each other and by 80 and 40deg against the orbital plane of the binary. The system might be a good case for primordial misalignment, as opposed to misalignment caused by dynamical interactions, because the outflow direction is constant and the realignment timescale is likely larger than the system age. This favours turbulent fragmentation, rather than rotational fragmentation, as the formation scenario. We show that the spectral energy distributions and images for the two objects can be reproduced with radiative transfer models for disk/envelope systems. Our analysis provides reassurance in the established paradigm for the structure and early evolution of YSOs, but stresses the importance of developing 3D models with sophisticated dust chemistry (abridged)., Comment: 14 pages, 11 figures, accepted for publication by MNRAS

A near-infrared imaging study of the evolved stellar populations in the dwarf spheroidal galaxy Leo I is presented. Based on JHK observations obtained with the WFCAM wide-field array at the UKIRT telescope, we build a near-infrared photometric catalogue of red giant branch (RGB) and asymptotic giant branch (AGB) stars in Leo I over a 13.5 arcmin square area. The V-K colours of RGB stars, obtained by combining the new data with existing optical observations, allow us to derive a distribution of global metallicity [M/H] with average [M/H] = -1.51 (uncorrected) or [M/H] = -1.24 +/- 0.05 (int) +/- 0.15 (syst) after correction for the mean age of Leo I stars. This is consistent with the results from spectroscopy once stellar ages are taken into account. Using a near-infrared two-colour diagram, we discriminate between carbon- and oxygen-rich AGB stars and obtain a clean separation from Milky Way foreground stars. We reveal a concentration of C-type AGB stars relative to the red giant stars in the inner region of the galaxy, which implies a radial gradient in the intermediate-age (1-3 Gyr) stellar populations. The numbers and luminosities of the observed carbon- and oxygen-rich AGB stars are compared with those predicted by evolutionary models including the thermally-pulsing AGB phase, to provide new constraints to the models for low-metallicity stars. We find an excess in the predicted number of C stars fainter than the RGB tip, associated to a paucity of brighter ones. The number of O-rich AGB stars is roughly consistent with the models, yet their predicted luminosity function is extended to brighter luminosity. It appears likely that the adopted evolutionary models overestimate the C star lifetime and underestimate their K-band luminosity., Comment: MNRAS, accepted

Intermediate resolution spectra at the Ca II triplet have been obtained for 55 candidate red giants in the field of the globular cluster M22 with the VLT/FORS instrument. Spectra were also obtained for a number of red giants in standard globular clusters to provide a calibration of the observed line strengths with overall abundance [Fe/H]. For the 41 M22 member stars that lie within the V-V_HB bounds of the calibration, we find an abundance distribution that is substantially broader than that expected from the observed errors alone. We argue that this broad distribution cannot be the result of differential reddening. Instead we conclude that, as has long been suspected, M22 is similar to omega Cen in having an intrinsic dispersion in heavy element abundance. The observed M22 abundance distribution rises sharply to a peak at [Fe/H] = -1.9 with a broad tail to higher abundances: the highest abundance star in our sample has [Fe/H] = -1.45 dex. If the unusual properties of omega Cen have their origin in a scenario in which the cluster is the remnant nucleus of a disrupted dwarf galaxy, then such a scenario likely applies also to M22., Comment: 29 pages, 9 figures, accepted for publication in the Astrophysical Journal

Context. NGC 205 is a peculiar dwarf elliptical galaxy hosting in its center a population of young blue stars. Their origin is still matter of debate, the central fresh star formation activity possibly being related to dynamical interactions between NGC 205 and M31. Aims. The star formation history in the central 30\arcsec ($\sim$120 pc) around the NGC 205 central nucleus is investigated in order to obtain clues to the origin of the young stellar population. Methods. Deep HST/ACS CCD photometry is compared with theoretical isochrones and luminosity functions to characterize the stellar content of the region under study and compute the recent SF rate. Results. Our photometry reveals a previously undetected blue plume of young stars clearly distinguishable down to I$\simeq$26. Our analysis suggests that 1.9$\times10^5$ M$_\odot$ were produced between approximately 62 Myr and 335 Myr ago in the NGC 205 inner regions, with a latest minor episode occurring $\sim$25 Myr ago. This implies a star formation rate of $\sim7\times10^{-4}$ M$_\odot$/yr over this period. Conclusions. The excellent fit of the observed luminosity function of young main sequence stars obtained with a model having a constant star formation rate argues against a tidally triggered star formation activity over the last $\sim$300 Myr. Rather, a constant SF may be consistent with NGC 205 being on its first interaction with M 31., Comment: 5 pages, 2 figures, accepted for publication in A&A letters

(Abridged) We present the spectroscopy of red giant stars in the dwarf spheroidal galaxy LeoI, aimed at further constraining its chemical enrichment history. Intermediate-resolution spectroscopy in the CaII triplet spectral region was obtained for 54 stars in LeoI using FORS2 at the ESO Very Large Telescope. The equivalent widths of CaII triplet lines were used to derive the metallicities of the target stars on the [Fe/H] scale of Carretta & Gratton, as well as on a scale tied to the global metal abundance, [M/H]. The metallicity distribution function for LeoI stars is confirmed to be very narrow, with mean value [M/H]~-1.2 and intrinsic dispersion, sigma_[M/H]=0.08. We find a few metal-poor stars (whose metallicity values depend on the adopted extrapolation of the existing calibrations), but in no case are stars more metal-poor than [Fe/H]=-2.6. Our measurements provide a hint of a shallow metallicity gradient of -0.27 dex/Kpc among LeoI red giants. By combining the metallicities of the target stars with their photometric data, we provide age estimates and an age-metallicity relation for a subset of red giant stars in LeoI. Our age estimates indicate a rapid initial enrichment, a slowly rising metal abundance and an increase of ~0.2 dex in the last few Gyr., Comment: Accepted for publication in Astronomy & Astrophysics

In the context of dwarf spheroidal galaxies it is hard to firmly disentangle a genuine Blue Stragglers (BSS) population from a normal young main (MS) sequence. This difficulty is persistent. For a sample of 9 non-star forming Local Group dwarf galaxies we compute the ``BSS frequency'' and compare it with that found in the Milky Way globular/open clusters and halo. The comparison shows that the BSS-frequency in dwarf galaxies, at any given Mv, is always higher than that in globular clusters of similar luminosities. Moreover, the estimated BSS-frequency for the lowest luminosity dwarf galaxies is in excellent agreement with that observed in the Milky Way halo and open clusters. We conclude that the low density, almost collision-less environment, of our dwarf galaxy sample point to their very low dynamical evolution and consequent negligible production of collisional BSS., Comment: 5 pages, 1 colour figure, contribution talk given at the Cefalu' 2007 Workshop "XXI Century Challenges for Stellar Evolution". To appear in Memorie della Societa' Astronomica Italiana, vol. 79/2, eds. S. Cassisi & M. Salaris

On 4 July 2005 at 05:52 UT, the impactor of NASA's Deep Impact (DI) mission crashed into comet 9P/Tempel 1 with a velocity of about 10 km/s. The material ejected by the impact expanded into the normal coma, produced by ordinary cometary activity. The characteristics of the non-impact coma and cloud produced by the impact were studied by observations in the visible wavelengths and in the near-IR. The scattering characteristics of the "normal" coma of solid particles were studied by comparing images in various spectral regions, from the UV to the near-IR. For the non-impact coma, a proxy of the dust production has been measured in various spectral regions. The presence of sublimating grains has been detected. Their lifetime was found to be about 11 hours. Regarding the cloud produced by the impact, the total geometric cross section multiplied by the albedo was measured as a function of the color and time. The projected velocity appeared to obey a Gaussian distribution with the average velocity of the order of 115 m/s. By comparing the observations taken about 3 hours after the impact, we have found a strong decrease in the cross section in J filter, while that in Ks remained almost constant. This is interpreted as the result of sublimation of grains dominated by particles of sizes of the order of some microns., Comment: Accepted by A&A

A large multicolour, wide-field photometric database of the Fornax dwarf spheroidal galaxy has been analysed using three different methods to provide revised distance estimates based on stellar populations in different age intervals. The distance to Fornax was obtained from the Tip of the Red Giant Branch measured by a new method, and using the luminosity of Horizontal Branch stars and Red Clump stars correc ted for stellar population effects. Assuming a reddening $E(B-V)=0.02$, the following distance moduli were derived: $(m-M)_0=20.71 \pm 0.07$ based on the Tip of the Red Giant Branch, $(m-M)_0=20.72 \pm 0.06$ from the level of the Horizontal Branch, and $(m-M)_0=20.73 \pm 0.09$ using the Red Clump method. The weighted mean distance modulus to Fornax is $(m-M)_0=20.72 \pm 0.04$. All these measurements agree within the errors, and are fully consistent with previous determinations and with the distance measurements obtained in a companion paper from near-infrared colour-magnitude diagrams., Comment: Accepted for publication on Monthly Notices of the Royal Astronomical Society

The Variable Star One-shot Project (VSOP) is aimed at (1) providing the variability type and spectral type of all unstudied variable stars, (2) process, publish, and make the data available as automatically as possible, and (3) generate serendipitous discoveries. This first paper describes the project itself, the acquisition of the data, the dataflow, the spectroscopic analysis and the on-line availability of the fully calibrated and reduced data. We also present the results on the 221 stars observed during the first semester of the project. We used the high-resolution echelle spectrographs HARPS and FEROS in the ESO La Silla Observatory (Chile) to survey known variable stars. Once reduced by the dedicated pipelines, the radial velocities are determined from cross correlation with synthetic template spectra, and the spectral types are determined by an automatic minimum distance matching to synthetic spectra, with traditional manual spectral typing cross-checks. The variability types are determined by manually evaluating the available light curves and the spectroscopy. In the future, a new automatic classifier, currently being developed by members of the VSOP team, based on these spectroscopic data and on the photometric classifier developed for the COROT and Gaia space missions, will be used. We confirm or revise spectral types of 221 variable stars from the GCVS. We identify 26 previously unknown multiple systems, among them several visual binaries with spectroscopic binary individual components. We present new individual results for the multiple systems V349 Vel and BC Gru, for the composite spectrum star V4385 Sgr, for the T-Tauri star V1045 Sco, and for DM Boo which we re-classify as a BY Draconis variable. The complete data release can be accessed via the VSOP web site., Comment: Accepted for publication in A&A

The relation between tidal interactions, starbursts, and the onset and/or fueling of active galactic nuclei (AGN) is a matter of debate. I Zw 1 is considered as the prototypical narrow-line Seyfert 1 galaxy (NLS1) and as one of the closest quasi-stellar objects (QSOs). With a clear spiral host and a small companion galaxy to the west, I Zw 1 is a possible example of minor-merger-related nuclear activity. This study investigates possible signs of a relation between merger process, star formation activity, and AGN properties in the case of I Zw 1. The morphology of I Zw 1 and nearby sources is investigated via high-resolution NIR images. Color trends in the host galaxy of I Zw 1 are discussed by means of optical-to-NIR color composites. Long-slit spectra of the QSO nucleus of I Zw 1 and of the two nearby sources to the north and the west of the I Zw 1 disk are analyzed. The data support the scenario of a tidal interaction between I Zw 1 and the small companion galaxy to the west. A concentration of blue color in the western part of the I Zw 1 host galaxy might be the manifestation of merger-induced star formation activity. Previous findings that the likely companion has an old evolved stellar population are substantiated by the new data. An extension to the west of the putative companion emerges as a separate source. The source to the north of the I Zw 1 disk is reconfirmed as a late-type foreground star. Lines in the nuclear K-band spectrum of I Zw 1 are discussed in comparison to data prior to this article and line fluxes are reported., Comment: 11 pages, 9 figures, accepted by A&A

The Variable Star One-shot Project (VSOP) aimed at providing to the world-wide stellar community the necessary one-shot spectrum of unstudied variable stars, too often classified as such by an analysis of photometric data only. The VSOP has established an new kind of observational model, where all steps from observations to spectral analysis, are automatized (or are underway to be fully automatized). The project is centralized on a collaborative wiki website. The VSOP operational model is very successful, data is continously flowing and being analyszed, and VSOP is now a worldwide open collaboration of people with very different and complementary skills and expertise. The idea of a central wiki website has been extended by one of us to propose a new service to the whole astronomical community, called Wikimbad. Wikimbad is an open wiki website aimed at collecting, organizing and making publicly available all kind of reduced and published astronomical data. Its strengths and a comparison with the Virtual Observatory are discussed. See: http://vsop.sc.eso.org and http://wikimbad.org, Comment: 4 pages, 3 figures, to appear in the proceedings of the workshop help at ESA, in March 2007, entitled "Astronomical Spectroscopy and Virtual Observatory"

Abridged... Blue stragglers (BSS) are thought to be the product of either primordial or collisional binary systems. In the context of dwarf spheroidal galaxies it is hard to firmly disentangle a genuine BSS population from young main sequence (MS) stars tracing a ~1-2 Gyr old star forming episode. Assuming that their blue plume populations are made of BSS, we estimate the BSS frequency for 8 Local Group non star-forming dwarf galaxies, using a compilation of ground and space based photometry. Our results can be summarized as follows: (i) The BSS frequency in dwarf galaxies, at any given Mv, is always higher than that in globular clusters of similar luminosities; (ii) the BSS frequency for the lowest luminosity dwarf galaxies is in excellent agreement with that observed in the Milky Way halo; and most interestingly (iii) derive a statistically significant anti-correlation between the BSS frequency and the galaxy Mv. The low density, almost collision-less, environments of our dwarf galaxy sample allow us to infer (i) their very low dynamical evolution; (ii) a negligible production of collisional BSS; and consequently (iii) that their blue plumes are mainly made of primordial binaries. The dwarf galaxies anti-correlation can be used as a discriminator: galaxies obeying the anti-correlation are more likely to possess genuine primordial BSS rather than young main sequence stars., Comment: Accepted for publication in Astronomy & Astrophysics, 7 pages, 3 figures