Examinando por Autor "Minniti, D."
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Ítem A Chemical and Kinematical Analysis of the Intermediate-age Open Cluster IC 166 from APOGEE and Gaia DR2(Institute of Physics Publishing, 2018-09) Schiappacasse-Ulloa, J.; Tang, B.; Fernández-Trincado, J.G.; Zamora, O.; Geisler, D.; Frinchaboy, P.; Schultheis, M.; Dell'Agli, F.; Villanova, S.; Masseron, T.; Mészáros, S.; Souto, D.; Hasselquist, S.; Cunha, K.; Smith, V.V.; García-Hernández, D.A.; Vieira, K.; Robin, A.C.; Minniti, D.; Zasowski, G.; Moreno, E.; Pérez-Villegas, A.; Lane, R.R.; Ivans, I.I.; Pan, K.; Nitschelm, C.; Santana, F.A.; Carrera, R.; Roman-Lopes, A.IC 166 is an intermediate-age open cluster (OC) (∼1 Gyr) that lies in the transition zone of the metallicity gradient in the outer disk. Its location, combined with our very limited knowledge of its salient features, make it an interesting object of study. We present the first high-resolution spectroscopic and precise kinematical analysis of IC 166, which lies in the outer disk with R GC ∼ 12.7 kpc. High-resolution H-band spectra were analyzed using observations from the SDSS-IV Apache Point Observatory Galactic Evolution Experiment survey. We made use of the Brussels Automatic Stellar Parameter code to provide chemical abundances based on a line-by-line approach for up to eight chemical elements (Mg, Si, Ca, Ti, Al, K, Mn, and Fe). The α-element (Mg, Si, Ca, and whenever available Ti) abundances, and their trends with Fe abundances have been analyzed for a total of 13 high-likelihood cluster members. No significant abundance scatter was found in any of the chemical species studied. Combining the positional, heliocentric distance, and kinematic information, we derive, for the first time, the probable orbit of IC 166 within a Galactic model including a rotating boxy bar, and found that it is likely that IC 166 formed in the Galactic disk, supporting its nature as an unremarkable Galactic OC with an orbit bound to the Galactic plane. © 2018. The American Astronomical Society.Ítem A colour-excess extinction map of the southern Galactic disc from the VVV and GLIMPSE surveys(Monthly Notices of the Royal Astronomical Society, 2019-09-11) Soto, M.; Barba, R.; Minniti, D.; Kunder, A.; Majaess, D.; Nilo-Castellon, J. L.; Alonso-García, J.; Leone, G.; Morelli, L.; Haikala, L.; Firpo, V.; Lucas, P.; Emerson, J. P.; Moni Bidin, C.; Geisler, D.; Saito, R. K.; Gurovich, S.; Contreras Ramos, R.; Rejkuba, M.; Barbieri, M.; Roman-Lopes, A.; Hempel, M.; Alonso, M. V.; Baravalle, L. D.; Borissova, J.; Kurtev, R.; Milla, F.An improved high-resolution and deep AKs foreground dust extinction map is presented for the Galactic disc area within 295◦ ≾ l ≾ 350◦, −1.0◦ ≾ b ≾ +1.0◦. At some longitudes the map reaches up to |b| ~ 2.25◦, for a total of ~148 deg2. The map was constructed via the Rayleigh–Jeans colour excess (RJCE) technique based on deep near-infrared (NIR) and mid-infrared (MIR) photometry. The new extinction map features a maximum bin size of 1 arcmin, and relies on NIR observations from the Two Micron All-Sky Survey (2MASS) and new data from ESO’s Vista Variables in the Vía Láctea (VVV) survey, in concert with MIR observations from the Galactic Legacy Infrared Mid-Plane Survey Extraordinaire. The VVV photometry penetrates ~4 mag fainter than 2MASS, and provides enhanced sampling of the underlying stellar populations in this heavily obscured region. Consequently, the new results supersede existing RJCE maps tied solely to brighter photometry, revealing a systematic underestimation of extinction in prior work that was based on shallower data. The new high-resolution and large-scale extinction map presented here is readily available to the community through a web query interface.Ítem A deep near-infrared view of the Ophiuchus galaxy cluster(EDP Sciences, 2022-07) Galdeano, D.; Coldwell, G.; Duplancic, F.; Alonso, S.; Pereyra, L.; Minniti, D.; Zelada Bacigalupo, R.; Valotto, C.; Baravalle, L.; Alonso, M.V.; Nilo Castellón, J.L.Context. The Ophiuchus cluster of galaxies, located at low latitudes in the direction of the Galactic bulge, has been relatively poorly studied in comparison with other rich galaxy clusters, such as Coma, Virgo, and Fornax, despite being the second brightest X-ray cluster in the sky. Aims. Our aim is perform a study of the hidden galaxy population of the massive cluster Ophiuchus located in the Zone of Avoidance. Methods. Deep near-infrared images and photometry from the VISTA Variables in the Vía Láctea eXtended (VVVX) survey were used to detect galaxy member candidates of the Ophiuchus cluster up to 2 Mpc from the cD galaxy 2MASX J17122774-2322108 using criteria from a past paper to select the galaxies among the foreground sources. We also perform a morphological visual classification and generate color-magnitude diagrams and density profiles. Results. We identify 537 candidate galaxy members of the Ophiuchus cluster up to 2 Mpc from the cD galaxy, increasing by a factor of seven the number of reported Ophiuchus galaxies. In addition, we performed a morphological classification of these galaxy candidates finding that the fraction of ellipticals reaches more than 60% in the central region of the cluster. On the other hand, the fraction of spirals fraction is lower than 20%, remaining almost constant throughout the cluster. Moreover, we study the red sequence of galaxy member candidates and use mock catalogs to explore the density profile of the cluster, finding that the value derived from the mock catalog toward an overdense region is in agreement with the galaxy excess of the central zone of the Ophiuchus cluster. Conclusions. Our investigation of the hidden population of Ophiuchus galaxies underscores the importance of this cluster as a prime target for future photometric and spectroscopic studies. Moreover the results of this work highlight the potential of the VVVX survey to study extragalactic objects in the Zone of Avoidance. © 2022 D. Galdeano et al.Ítem A new low-luminosity globular cluster discovered in the Milky Way with the VVVX survey(EDP Sciences, 2022-06) Garro, E.R.; Minniti, D.; Gómez, M.; Fernández-Trincado, J.G.; Alonso-García, J.; Hempel, M.; Zelada Bacigalupo, R.Context. The VISTA Variables in the Via Láctea Extended Survey (VVVX) allows us to probe previously unexplored regions of the inner Milky Way (MW), especially those that are affected by stellar crowding and strong extinction. Aims. Our long-term goal is to identify new star clusters and investigate them to reveal their true nature. In particular, we are looking for new candidate globular clusters (GCs) located in the Galactic bulge and disk, with the aim of completing the census of theMWGC system. Methods. We searched and characterised new GCs, using a combination of the near-infrared (IR) VVVX survey and Two Micron All Sky survey (2MASS) datasets, and the optical Gaia Early Data Release 3 (EDR3) photometry and its precise proper motions (PMs). Results. We report the discovery of a new Galactic GC, named Garro 02, situated at RA= 18:05:51.1, Dec = 17:42:02 and l = 12:°042, b = +1:°656. Performing a PM-decontamination procedure, we built a final catalogue with all cluster members, on which we performed a photometric analysis.We calculated a reddening of E(J Ks) = 1:07±0:06 mag and extinction of AKs = 0:79±0:04 mag in the near-IR; while E(BP RP) = 2:40 ± 0:01 mag and AG = 4:80 ± 0:02 mag in optical passbands. Its heliocentric distance is D = 5:6±0:8 kpc, which places Garro 02 at a Galactocentric distance of RG = 2:9 kpc and Z = 0:006 kpc above the Galactic plane.We also estimated the metallicity and age by comparison with known GCs and by fitting PARSEC isochrones, finding [Fe/H] = 1:30±0:2 dex and age = 12 ± 2 Gyr. We derived the mean cluster PM of (μα ff; μ°) = (6:07 ± 0:62; 6:15 ± 0:75) mas yr1. We calculated the cluster luminosity in the near-IR of MKs = 7:52±1:23 mag, which is equivalent to MV = 5:44 mag. The core and tidal radii from the radial density profile are rc = 1:25 ± 0:27 arcmin (2.07 pc) and rt = 7:13 ± 3:83 arcmin (11.82 pc), respectively. Conclusions. We confirm Garro 02 as a new genuine Galactic GC, located in the MW bulge. It is a low-luminosity, metal-poor, and old GC, and it is a lucky survivor of the strong dynamical processes that occurred during the MW’s entire life. © E. R. Garro et al. 2022.Ítem A new near-IR window of low extinction in the Galactic plane(EDP Sciences, 2018-08) Minniti, D.; Saito, R.K.; Gonzalez, O.A.; Alonso-García, J.; Rejkuba, M.; Barbá, R.; Irwin, M.; Kammers, R.; Lucas, P.W.; Majaess, D.; Valenti, E.Aims. The windows of low extinction in the Milky Way (MW) plane are rare but important because they enable us to place structural constraints on the opposite side of the Galaxy, which has hither to been done rarely. Methods. We use the near-infrared (near-IR) images of the VISTA Variables in the Vía Láctea (VVV) Survey to build extinction maps and to identify low extinction windows towards the Southern Galactic plane. Here we report the discovery of VVV WIN 1713-3939, a very interesting window with relatively uniform and low extinction conveniently placed very close to the Galactic plane. Results. The new window of roughly 30 arcmin diameter is located at Galactic coordinates (l, b) = (347.4, -0.4) deg. We analyse the VVV near-IR colour-magnitude diagrams in this window. The mean total near-IR extinction and reddening values measured for this window are A Ks = 0.46 and E(J - K s ) = 0.95. The red clump giants within the window show a bimodal magnitude distribution in the K s band, with peaks at K s = 14.1 and 14.8 mag, corresponding to mean distances of D = 11.0 ± 2.4 and 14.8 ± 3.6 kpc, respectively. We discuss the origin of these red clump overdensities within the context of the MW disk structure. © ESO 2018.Ítem A population of eruptive variable protostars in VVV(OXFORD UNIV PRESS, 2016-11) Contreras Peña, C.; Lucas, P.W.; Minniti, D.; Kurtev, R.; Stimson, W.; Navarro Molina, C.; Borissova, J.; Kumar, M.S.N.; Thompson, M.A.; Gledhill, T.; Terzi, R.; Froebrich, D.; Caratti o Garatti, A.We present the discovery of 816 high-amplitude infrared variable stars (ΔKs > 1 mag) in 119 deg2 of the Galactic mid-plane covered by the VISTA Variables in the Via Lactea (VVV) survey. Almost all are new discoveries and about 50 per cent are young stellar objects (YSOs). This provides further evidence that YSOs are the commonest high-amplitude infrared variable stars in the Galactic plane. In the 2010-2014 time series of likely YSOs, we find that the amplitude of variability increases towards younger evolutionary classes (class I and flatspectrum sources) except on short time-scales (< 25 d) where this trend is reversed. Dividing the likely YSOs by light-curve morphology, we find 106 with eruptive light curves, 45 dippers, 39 faders, 24 eclipsing binaries, 65 long-term periodic variables (P > 100 d) and 162 shortterm variables. Eruptive YSOs and faders tend to have the highest amplitudes and eruptive systems have the reddest spectral energy distribution (SEDs). Follow-up spectroscopy in a companion paper verifies high accretion rates in the eruptive systems. Variable extinction is disfavoured by the two epochs of colour data. These discoveries increase the number of eruptive variable YSOs by a factor of at least 5, most being at earlier stages of evolution than the known FUor and EXor types. We find that eruptive variability is at least an order of magnitude more common in class I YSOs than class II YSOs. Typical outburst durations are 1-4 yr, between those of EXors and FUors. They occur in 3-6 per cent of class I YSOs over a 4 yr time spanÍtem A qualitative classification of extraterrestrial civilizations(EDP Sciences, 2020-07) Ivanov, V.D.; Beamín, J.C.; Cáceres, C.; Minniti, D.Context. Interest in searches for extraterrestrial civilizations (ETCs) has been boosted in recent decades by the discovery of thousands of exoplanets. Aims. We turn to the classification of ETCs for new considerations that may help to design better strategies for searching for ETCs. Methods. This study is based on analogies with our own biological, historical, technological, and scientific development. We took a basic taxonomic approach to ETCs and investigated the implications of the new classification on ETC evolution and observational patterns. Finally, we used the quantitative scheme of Kardashev and considered its implications on the searches for ETCs as a counter example to our qualitative classification. Results. We propose a classification based on the abilities of ETCs to modify and integrate with their environments: Class 0 uses the environment as it is, Class 1 modifies the environment to fit its needs, Class 2 modifies itself to fit the environment, and a Class 3 ETC is fully integrated with the environment. Combined with the classical Kardashev scale, our scheme forms a two-dimensional method for interpreting ETC properties. Conclusions. The new framework makes it obvious that the available energy is not a unique measure of ETC progress: it may not even correlate with how well that energy is used. The possibility for progress without increased energy consumption implies a lower detectability, so in principle the existence of a Kardashev Type III ETC in the Milky Way cannot be ruled out. This reasoning weakens the Fermi paradox, allowing for the existence of advanced, yet not energy hungry, low-detectability ETCs. The integration of ETCs with the environment will make it impossible to tell technosignatures and natural phenomena apart. Therefore, the most likely opportunity for SETI searches to find advanced ETCs is to look for beacons, specifically set up by them for young civilizations like ours (if they would want to do that remains a matter of speculation). The other SETI window of opportunity is to search for ETCs at technological level similar to ours. To rephrase the famous saying of Arthur Clarke, sufficiently advanced civilizations are indistinguishable from nature. © ESO 2020.Ítem Abundance analysis of APOGEE spectra for 58 metal-poor stars from the bulge spheroid(Oxford University Press, 2022-12-01) Razera, R.; Barbuy, B.; Moura, T.C.; Ernandes, H.; Pérez Villegas, A.; Souza, S.O.; Chiappini, C.; Queiroz, A.B.A.; Anders, F.; Fernández Trincado, J.G.; Friaça, A.C.S.; Cunha, K.; Smith, V.V.; Santiago, B.X.; Schiavon, R.P.; Valentini, M.; Minniti, D.; Schultheis, M.; Geisler, D.; Sobeck, J.; Placco, V.M.; Zoccali, M.The central part of the Galaxy hosts a multitude of stellar populations, including the spheroidal bulge stars, stars moved to the bulge through secular evolution of the bar, inner halo, inner thick disc, inner thin disc, as well as debris from past accretion events. We identified a sample of 58 candidate stars belonging to the stellar population of the spheroidal bulge, and analyse their abundances. The present calculations of Mg, Ca, and Si lines are in agreement with the ASPCAP abundances, whereas abundances of C, N, O, and Ce are re-examined. We find normal α-element enhancements in oxygen, similar to magnesium, Si, and Ca abundances, which are typical of other bulge stars surveyed in the optical in Baade's Window. The enhancement of [O/Fe] in these stars suggests that they do not belong to accreted debris. No spread in N abundances is found, and none of the sample stars is N-rich, indicating that these stars are not second generation stars originated in globular clusters. Ce instead is enhanced in the sample stars, which points to an s-process origin such as due to enrichment from early generations of massive fast rotating stars, the so-called spinstars. © 2022 The Author(s) Published by Oxford University Press on behalf of Royal Astronomical Society.Ítem An Automated Tool to Detect Variable Sources in the Vista Variables in the Vía Láctea Survey: The VVV Variables (V4) Catalog of Tiles d001 and d002(Institute of Physics Publishing, 2018-09) Medina, N.; Borissova, J.; Bayo, A.; Kurtev, R.; Navarro Molina, C.; Kuhn, M.; Kumar, N.; Lucas, P.W.; Catelan, M.; Minniti, D.; Smith, L.C.Time-varying phenomena are one of the most substantial sources of astrophysical information, and their study has led to many fundamental discoveries in modern astronomy. We have developed an automated tool to search for and analyze variable sources in the near-infrared K s band using the data from the VISTA Variables in the Vía Láctea (VVV) ESO Public Large Survey. This process relies on the characterization of variable sources using different variability indices calculated from time series generated with point-spread function (PSF) photometry of sources under analysis. In particular, we used two main indices, the total amplitude and the eta index η, to identify variable sources. Once the variable objects are identified, periods are determined with generalized Lomb-Scargle periodograms and the information potential metric. Variability classes are assigned according to a compromise between comparisons with VVV templates and the period of the variability. The automated tool is applied on VVV tiles d001 and d002 and led to the discovery of 200 variable sources. We detected 70 irregular variable sources and 130 periodic ones. In addition, nine open-cluster candidates projected in the region are analyzed, and the infrared variable candidates found around these clusters are further scrutinized by cross-matching their locations against emission star candidates from VPHAS+ survey Hα color cuts. © 2018. The American Astronomical Society. All rights reserved.Ítem Bulge RR Lyrae stars in the VVV tile b201(EDP Sciences, 2015-03) Gran, F.; Minniti, D.; Saito, R.K.; Navarrete, C.; Dékány, I.; McDonald, I.; Contreras Ramos, R.; Catelan, M.Context. The VISTA Variables in the Vía Láctea (VVV) Survey is one of the six ESO public surveys currently ongoing at the VISTA telescope on Cerro Paranal, Chile. VVV uses near-IR (ZYJHKs) filters that at present provide photometry to a depth of Ks ∼ 17:0 mag in up to 36 epochs spanning over four years, and aim at discovering more than 106 variable sources as well as trace the structure of the Galactic bulge and part of the southern disk. Aims. A variability search was performed to find RR Lyrae variable stars. The low stellar density of the VVV tile b201, which is centered at (l, b) ∼ (-9°, -9°), makes it suitable to search for variable stars. Previous studies have identified some RR Lyrae stars using optical bands that served to test our search procedure. The main goal is to measure the reddening, interstellar extinction, and distances of the RR Lyrae stars and to study their distribution on the Milky Way bulge. Methods. For each star in the tile with more than 25 epochs (∼90% of the objects down to Ks ∼ 17:0 mag), the standard deviation and x2 test were calculated to identify variable candidates. Periods were determined using the analysis of variance. Objects with periods in the RR Lyrae range of 0:2 ≤ P ≤ 1:2 days were selected as candidate RR Lyrae. They were individually examined to exclude false positives. Results. A total of 1.5 sq deg were analyzed, and we found 39 RR Lyr stars, 27 of which belong to the ab-type and 12 to the c-type. Our analysis recovers all the previously identified RR Lyrae variables in the field and discovers 29 new RR Lyr stars. The reddening and extinction toward all the RRab stars in this tile were derived, and distance estimations were obtained through the period-luminosity relation. Despite the limited amount of RR Lyrae stars studied, our results are consistent with a spheroidal or central distribution around ∼8.1 and ∼8.5 kpc. for either the Cardelli or Nishiyama extinction law. Our analysis does not reveal a stream-like structure. Nevertheless, a larger area must be analyzed to definitively rule out streams. © ESO 2015.Ítem Ca triplet metallicities and velocities for 12 globular clusters toward the galactic bulge(EDP Sciences, 2023-01) Geisler, D.; Parisi, M.C.; Dias, B.; Villanova, S.; Mauro, F.; Saviane, I.; Cohen, R.E.; Moni Bidin C.; Minniti, D.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. Aims. Our aim is to derive the mean metallicities and radial velocities for 13 GCs that lie toward the bulge and are generally associated with this component. This region is observationally challenging because of high extinction and stellar density, which hampers optical studies of these and similar BGCs, making most previous determinations of these parameters quite uncertain. Methods. We used near-infrared low-resolution spectroscopy with the FORS2 instrument on the VLT to measure the wavelengths and equivalent widths of the Call triplet (CaT) lines for a number of stars per cluster. We derived radial velocities, ascertained membership, and applied known calibrations to determine metallicities for cluster members, for a mean of 11 members per cluster. Unfortunately, one of our targets, VVV-GC002, which is the closest GC to the Galactic center, turned out not to have any members in our sample. Results. We derive mean cluster RV values to 3 km s~1, and mean metallicities to 0.05 dex. We find general good agreement with previous determinations for both metallicity and velocity. On average, our metallicities are 0.07 dex more metal-rich than those of Harris (2010, arXiv: 1012.3224), with a standard deviation of the difference of 0.25 dex. Our sample has metallicities between -0.21 and -1.64. and the values are distributed between the traditional metal-rich BGC peak near [Fe/H] -0.5 and a more metal-poor peak around [Fe/H] -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 BH261, NGC6401, NGC6540, NGC6642, and Terzan9. 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 Oosterhoff type II GC based on our results. Conclusions. The CaT technique is an excellent method for deriving mean metallicities and velocities for heavily obscured GCs. Our sample provides reliable mean values for these two key properties via spectroscopy of a significant number of members per cluster for this important yet previously poorly studied sample of BGCs. We emphasize that the more metal-poor GCs are excellent candidates for being ancient relics of bulge formation. 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 bona fide BGCs at metallicities below about -1.5. © 2023 EDP Sciences. All rights reserved.Ítem Candidate star clusters toward the inner Milky Way discovered on deep-stacked KS-band images from the VVV Survey(EDP Sciences, 2017) Ivanov, V.D.; Piatti, A.E.; Beamín, J.-C.; Minniti, D.; Borissova, J.; Kurtev, R.; Hempel, M.; Saito, R.K.This paper is based on observations made with ESO telescopes at the La Silla Paranal Observatory under program ID 092.B-0104(A). We have made extensive use of the SIMBAD Database at CDS (Centre de Données astronomiques) Strasbourg, the NASA/IPAC Extragalactic Database (NED), which is operated by the Jet Propulsion Laboratory, CalTech, under contract with NASA, and of the VizieR catalog access tool, CDS, Strasbourg, France. Support for J.B., D.M., J.C.B., R.K., M.H. is provided by the Ministry of Economy, Development, and Tourism's Millennium Science Initiative through grant IC120009, awarded to The Millennium Institute of Astrophysics, MAS. Support for R.K. is provided from Fondecyt Reg. No. 1130140. R.K.S. acknowledges support from CNPq/Brazil through project 310636/2013-2. We are grateful to the anonymous referee for useful suggestions that helped to improve the paper.Ítem Characterization of the VVV Survey RR Lyrae Population across the Southern Galactic Plane(IOP PUBLISHING, 2017-03) Minniti, D.; Dékány, I.; Majaess, D.; Palma, T.; Pullen, J.; Rejkuba, M.; Alonso-García, J.; Catelan, M.; Contreras Ramos, R.; Gonzalez, O.A.; Hempel, M.; Irwin, M.l; Lucas, P.W.; Saito, R.K.; Tissera, P.; Valenti, E.; Zoccali, M.Deep near-IR images from the VISTA Variables in the Via Lactea (VVV) Survey were used to search for RR Lyrae stars in the Southern Galactic plane. A sizable sample of 404 RR Lyrae of type ab stars was identified across a thin slice of the fourth Galactic quadrant (295 degrees < l < 350 degrees, -2 degrees.24 < b < -1 degrees.05). The sample's distance distribution exhibits a maximum density that occurs at the bulge tangent point, which implies that this primarily Oosterhoff type I population of RRab stars does not trace the bar delineated by their red clump counterparts. The bulge RR Lyrae population does not extend beyond l similar to 340 degrees, and the sample's spatial distribution presents evidence of density enhancements and substructure that warrants further investigation. Indeed, the sample may be employed to evaluate Galactic evolution models, and is particularly lucrative since half of the discovered RR Lyrae are within reach of Gaia astrometric observations.Ítem Chemically Dissected Rotation Curves of the Galactic Bulge from Main-sequence Proper Motions(Institute of Physics Publishing, 2018-05) Clarkson, W.I.; Calamida, A.; Sahu, K.C.; Brown, T.M.; Gennaro, M.; Avila, R.J.; Valenti, J.; Debattista, V.P.; Rich, R.M.; Minniti, D.; Zoccali, M.; Aufdemberge, E.R.We report results from an exploratory study implementing a new probe of Galactic evolution using archival Hubble Space Telescope imaging observations. Precise proper motions are combined with photometric relative metallicity and temperature indices, to produce the proper-motion rotation curves of the Galactic bulge separately for metal-poor and metal-rich main-sequence samples. This provides a "pencil-beam" complement to large-scale wide-field surveys, which to date have focused on the more traditional bright giant branch tracers. We find strong evidence that the Galactic bulge rotation curves drawn from "metal-rich" and "metal-poor" samples are indeed discrepant. The "metal-rich" sample shows greater rotation amplitude and a steeper gradient against line-of-sight distance, as well as possibly a stronger central concentration along the line of sight. This may represent a new detection of differing orbital anisotropy between metal-rich and metal-poor bulge objects. We also investigate selection effects that would be implied for the longitudinal proper-motion cut often used to isolate a "pure-bulge" sample. Extensive investigation of synthetic stellar populations suggests that instrumental and observational artifacts are unlikely to account for the observed rotation curve differences. Thus, proper-motion-based rotation curves can be used to probe chemodynamical correlations for main-sequence tracer stars, which are orders of magnitude more numerous in the Galactic bulge than the bright giant branch tracers. We discuss briefly the prospect of using this new tool to constrain detailed models of Galactic formation and evolution. © 2018. The American Astronomical Society. All rights reserved.Ítem Comparing the properties of the X-shaped bulges of NGC 4710 and the Milky Way with MUSE(EDP SCIENCES, 2016-06) Gonzalez, O. A.; Gadotti, D. A.; Debattista, V. P.; Rejkuba, M.; Valenti, E.; Zoccali, M.; Coccato, L.; Minniti, D.; Ness, M.Context. Our view of the structure of the Milky Way and, in particular, its bulge is obscured by the intervening stars, dust, and gas in the disc. While great progress in understanding the bulge has been achieved with past and ongoing observations, the comparison of its global chemodynamical properties with respect to those of bulges seen in external galaxies has yet to be accomplished. Aims. We used the Multi Unit Spectroscopic Explorer (MUSE) instrument installed on the Very Large Telescope (VLT) to obtain spectral and imaging coverage of NGC 4710. The wide area and excellent sampling of the MUSE integral field spectrograph allows us to investigate the dynamical properties of the X-shaped bulge of NGC 4710 and compare it with the properties of the X-shaped bulge of the Milky Way. Methods. We measured the radial velocities, velocity dispersion, and stellar populations using a penalised pixel full spectral fitting technique adopting simple stellar populations models, on a 1′ × 1′ area centred on the bulge of NGC 4710. We constructed the velocity maps of the bulge of NGC 4710 and investigated the presence of vertical metallicity gradients. These properties were compared to those of the Milky Way bulge and to a simulated galaxy with a boxy-peanut bulge. Results. We find the line-of-sight velocity maps and 1D rotation curves of the bulge of NGC 4710 to be remarkably similar to those of the Milky Way bulge. Some specific differences that were identified are in good agreement with the expectations from variations in the bar orientation angle. The bulge of NGC 4710 has a boxy-peanut morphology with a pronounced X-shape, showing no indication of any additional spheroidally distributed bulge population, in which we measure a vertical metallicity gradient of 0.35 dex/kpc. Conclusions. The general properties of NGC 4710 are very similar to those observed in the Milky Way bulge. However, it has been suggested that the Milky Way bulge has an additional component that is comprised of the oldest, most metal-poor stars, which is not part of the boxy-peanut bulge structure. Such a population is not observed in NGC 4710, but could be hidden in the integrated light we observed.Ítem Comparing the properties of the X-shaped bulges of NGC 4710 and the Milky Way with MUSE(EDP Sciences, 2016) Gonzalez, O.A.; Gadotti, D.A.; Debattista, V.P.; Rejkuba, M.de; Valenti, E.; Zoccali, M.; Coccato, L.; Minniti, D.; Ness, M.Context. Our view of the structure of the Milky Way and, in particular, its bulge is obscured by the intervening stars, dust, and gas in the disc. While great progress in understanding the bulge has been achieved with past and ongoing observations, the comparison of its global chemodynamical properties with respect to those of bulges seen in external galaxies has yet to be accomplished. Aims. We used the Multi Unit Spectroscopic Explorer (MUSE) instrument installed on the Very Large Telescope (VLT) to obtain spectral and imaging coverage of NGC 4710. The wide area and excellent sampling of the MUSE integral field spectrograph allows us to investigate the dynamical properties of the X-shaped bulge of NGC 4710 and compare it with the properties of the X-shaped bulge of the Milky Way. Methods. We measured the radial velocities, velocity dispersion, and stellar populations using a penalised pixel full spectral fitting technique adopting simple stellar populations models, on a 1′ × 1′ area centred on the bulge of NGC 4710. We constructed the velocity maps of the bulge of NGC 4710 and investigated the presence of vertical metallicity gradients. These properties were compared to those of the Milky Way bulge and to a simulated galaxy with a boxy-peanut bulge. Results. We find the line-of-sight velocity maps and 1D rotation curves of the bulge of NGC 4710 to be remarkably similar to those of the Milky Way bulge. Some specific differences that were identified are in good agreement with the expectations from variations in the bar orientation angle. The bulge of NGC 4710 has a boxy-peanut morphology with a pronounced X-shape, showing no indication of any additional spheroidally distributed bulge population, in which we measure a vertical metallicity gradient of 0.35 dex/kpc. Conclusions. The general properties of NGC 4710 are very similar to those observed in the Milky Way bulge. However, it has been suggested that the Milky Way bulge has an additional component that is comprised of the oldest, most metal-poor stars, which is not part of the boxy-peanut bulge structure. Such a population is not observed in NGC 4710, but could be hidden in the integrated light we observed.Ítem Cool stars in the Galactic center as seen by APOGEE: M giants, AGB stars, and supergiant stars and candidates(EDP Sciences, 2020-10) Schultheis, M.; Rojas-Arriagada, A.; Cunha, K.; Zoccali, M.; Chiappini, C.; Zasowski, G.; Queiroz, A.B.A.; Minniti, D.; Fritz, T.; Garciá-Hernández, D.A.; Nitschelm, C.; Zamora, O.The Galactic center region, including the nuclear disk, has until recently been largely avoided in chemical census studies because of extreme extinction and stellar crowding. Large, near-IR spectroscopic surveys, such as the Apache Point Observatory Galactic Evolution Experiment (APOGEE), allow the measurement of metallicities in the inner region of our Galaxy. Making use of the latest APOGEE data release (DR16), we are able for the first time to study cool Asymptotic Giant branch (AGB) stars and supergiants in this region. The stellar parameters of five known AGB stars and one supergiant star (VR 5-7) show that their location is well above the tip of the red giant branch. We studied metallicities of 157 M giants situated within 150 pc of the Galactic center from observations obtained by the APOGEE survey with reliable stellar parameters from the APOGEE pipeline making use of the cool star grid down to 3200 K. Distances, interstellar extinction values, and radial velocities were checked to confirm that these stars are indeed situated in the Galactic center region. We detect a clear bimodal structure in the metallicity distribution function, with a dominant metal-rich peak of [Fe/H] ∼+0.3 dex and a metal-poor peak around {Fe/H] = -0.5 dex, which is 0.2 dex poorer than Baade's Window. The α-elements Mg, Si, Ca, and O show a similar trend to the Galactic bulge. The metal-poor component is enhanced in the α-elements, suggesting that this population could be associated with the classical bulge and a fast formation scenario. We find a clear signature of a rotating nuclear stellar disk and a significant fraction of high-velocity stars with vgal > 300 km s-1; the metal-rich stars show a much higher rotation velocity (∼200 km s-1) with respect to the metal-poor stars (∼140 km s-1). The chemical abundances as well as the metallicity distribution function suggest that the nuclear stellar disk and the nuclear star cluster show distinct chemical signatures and might be formed differently. © M. Schultheis et al. 2020.Ítem Discovery of a brown dwarf companion to the A3V star β Circini(Oxford University Press, 2015-12) Smith, L.C.; Lucas, P.W.; Contreras Peña, C.; Kurtev, R.; Marocco, F.; Jones, H.R.A.; Beamin, J.C.; Napiwotzki, R.; Borissova, J.; Burningham, B.; Faherty, J.; Pinfield, D.J.; Gromadzki, M.; Ivanov, V.D.; Minniti, D.; Stimson, W.; Villanueva, V.We report the discovery of an L dwarf companion to the A3V star β Circini. VVV J151721.49−585131.5, or β Cir B, was identified in a proper motion and parallax catalogue of the VISTA Variables in the Vía Láctea survey as having near-infrared luminosity and colour indicative of an early L dwarf, and a proper motion and parallax consistent with that of β Cir. The projected separation of ∼3.6 arcmin corresponds to 6656 au, which is unusually wide. The most recent published estimate of the age of the primary combined with our own estimate based on newer isochrones yields an age of 370–500 Myr. The system therefore serves as a useful benchmark at an age greater than that of the Pleiades brown dwarfs and most other young L dwarf benchmarks. We have obtained a medium resolution echelle spectrum of the companion which indicates a spectral type of L1.0 ± 0.5 and lacks the typical signatures of low-surface gravity seen in younger brown dwarfs. This suggests that signs of low-surface gravity disappear from the spectra of early L dwarfs by an age of ∼370–500 Myr, as expected from theoretical isochrones. The mass of β Cir B is estimated from the BHAC15 isochrones as 0.056 ± 0.007 M⊙.Ítem Discovery of a pair of classical cepheids in an invisible cluster beyond the galactic bulge(Institute of Physics Publishing, 2015-01) Dékány, I.; Minniti, D.; Alonso-García, J.; Hempel, M.; Palma, T.; Catelan, M.; Gieren, W.; Majaess, D.We report the discovery of a pair of extremely reddened classical Cepheid variable stars located in the Galacticplane behind the bulge, using near-infrared (NIR) time-series photometry from the VISTA Variables in the VaLáctea Survey. This is the first time that such objects have ever been found in the opposite side of the Galacticplane. The Cepheids have almost identical periods, apparent brightnesses, and colors. From the NIR Leavitt law,we determine their distances with ∼1.5% precision and ∼8% accuracy. We find that they have a same totalextinction of A(V) ? 32 mag, and are located at the same heliocentric distance of ádn = 11.4 ± 0.9 kpc, and lessthan 1 pc from the true Galactic plane. Their similar periods indicate that the Cepheids are also coeval, with an ageof ∼48 ± 3Myr, according to theoretical models. They are separated by an angular distance of only 18?.3,corresponding to a projected separation of ∼1 pc. Their position coincides with the expected location of the Far 3kpc Arm behind the bulge. Such a tight pair of similar classical Cepheids indicates the presence of an underlyingyoung open cluster that is both hidden behind heavy extinction and disguised by the dense stellar field of the bulge.All our attempts to directly detect this invisible cluster have failed, and deeper observations are needed.Ítem Disentangling the Galactic Halo with APOGEE. I. Chemical and Kinematical Investigation of Distinct Metal-poor Populations(Institute of Physics Publishing, 2018) Hayes, C.R.; Majewski, S.R.; Shetrone, M.; Fernández-Alvar, E.; Prieto, C.A.; Schuster, W.J.; Carigi, L.; Cunha, K.; Smith, V.V.; Sobeck, J.; Almeida, A.; Beers, T.C.; Carrera, R.; Fernández-Trincado, J.G.; García-Hernández, D.A.; Geisler, D.; Lane, R.R.; Lucatello, S.; Matthews, A.M.; Minniti, D.; Nitschelm, C.; Tang, B.; Tissera, P.B.; Zamora, O.We find two chemically distinct populations separated relatively cleanly in the [Fe/H]-[Mg/Fe] plane, but also distinguished in other chemical planes, among metal-poor stars (primarily with metallicities [Fe H] < -0.9) observed by the Apache Point Observatory Galactic Evolution Experiment (APOGEE) and analyzed for Data Release 13 (DR13) of the Sloan Digital Sky Survey. These two stellar populations show the most significant differences in their [X/Fe] ratios for the α-elements, C+N, Al, and Ni. In addition to these populations having differing chemistry, the low metallicity high-Mg population (which we denote "the HMg population") exhibits a significant net Galactic rotation, whereas the low-Mg population (or "the LMg population") has halo-like kinematics with little to no net rotation. Based on its properties, the origin of the LMg population is likely an accreted population of stars. The HMg population shows chemistry (and to an extent kinematics) similar to the thick disk, and is likely associated with in situ formation. The distinction between the LMg and HMg populations mimics the differences between the populations of low- and high-α halo stars found in previous studies, suggesting that these are samples of the same two populations.