Examinando por Autor "Gómez, M."
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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 Early-type galaxies in the Antlia cluster: Catalogue and isophotal analysis(Oxford University Press, 2018-06) Calderón, J.P.; Bassino, L.P.; Cellone, S.A.; Gómez, M.We present a statistical isophotal analysis of 138 early-type galaxies in the Antlia cluster, located at a distance of ~35 Mpc. The observational material consists of CCD images of four 36 ×36 arcmin2 fields obtained with theMOSAIC II camera at the Blanco 4-m telescope at Cerro Tololo Interamerican Observatory. Our present work supersedes previous Antlia studies in the sense that the covered area is four times larger, the limiting magnitude is MB ~ -9.6 mag, and the surface photometry parameters of each galaxy are derived from Sérsic model fits extrapolated to infinity. In a companion previous study we focused on the scaling relations obtained by means of surface photometry, and now we present the data, on which the previous paper is based, the parameters of the isophotal fits as well as an isophotal analysis. For each galaxy, we derive isophotal shape parameters along the semimajor axis and search for correlations within different radial bins. Through extensive statistical tests, we also analyse the behaviour of these values against photometric and global parameters of the galaxies themselves. While some galaxies do display radial gradients in their ellipticity (∈) and/or their Fourier coefficients, differences in mean values between adjacent regions are not statistically significant. Regarding Fourier coefficients, dwarf galaxies usually display gradients between all adjacent regions, while non-dwarfs tend to show this behaviour just between the two outermost regions. Globally, there is no obvious correlation between Fourier coefficients and luminosity for the whole magnitude range (-12 ≳ MV ≳ -22); however, dwarfs display much higher dispersions at all radii. © 2018 The Author(s). Published by Oxford University Press on behalf of the Royal Astronomical Society.Ítem Early-type galaxies in the Antlia cluster: Global properties(Oxford University Press, 2020-09) Calderón, J.P.; Bassino, L.P.; Cellone, S.A.; Gómez, M.; Caso, J.P.We present an extension of our previous research on the early-type galaxy population of the Antlia cluster (d ~ 35 Mpc), achieving a total coverage of ~2.6 deg2 and performing surface photometry for ~300 galaxies, 130 of which are new uncatalogued ones. Such new galaxies mainly fall in the low surface brightness (LSB) regime, but there are also some lenticulars (S0), which support the existence of unique functions that connect bright and dwarf galaxies in the scaling relations. We analyse the projected spatial distribution of galaxies up to a distance of ~800 kpc from NGC 3268, the adopted centre, as well as the radial velocity distribution and the correlation between galaxy colour and effective radius with the projected spatial distribution. We also obtain the luminosity function of the early-type galaxies and the distribution of stellar masses using the T1-band magnitudes and adopted mass-luminosity ratios. Additionally, we correlate the central galaxy distribution with an X-ray emission map from the literature. Based on the analysis of the radial velocities and galaxy colour distributions, we find that galaxies redder than the colour-magnitude relation (CMR) have a velocity distribution strongly concentrated towards the values of the dominant galaxies and are homogeneously distributed throughout the cluster. Those bluer than the CMR, in turn, have a much more extended radial velocity distribution and are concentrated towards the centre of the cluster. We also identify 12 candidates to ultra diffuse galaxies, which seem to be split into two families, and speculate about their origins in the context of the cluster structure. © 2020 The Author(s).Ítem From pharmacology to toxicology. Chemistry in the courtroom and the development of a judicial expertise, Santiago de Chile, 1831-1897(Universidad de Antioquia, 2020) Gómez, M.This article explores the development of chemical skills in Santiago de Chile through the judicial experts that participated in poisoning cases between 1831 and 1897. It aims to identify these experts and to investigate their relationship with certain knowledges -specifically pharmacy and toxicology-, in order to connect their work and disciplinary experience, with the conformation of their judicial expertise. Additionally, the study focusses on the relationship between science and the State, from the particular perspective of the judicial apparatus.Ítem Inspection of 19 globular cluster candidates in the Galactic bulge with the VVV survey(EDP Sciences, 2022-02) Garro, E. R.; Minniti, D.; Gómez, M.; J. Alonso-García; Ripepi, V.; . Fernández-Trincado, J. G; Vivanco Cádiz, F.Abstract Context. The census of the globular clusters (GCs) in the Milky Way is still a work in progress. The advent of new deep surveys has made it possible to discover many new star clusters both in the Galactic disk and bulge, but many of these new candidates have not yet been studied in detail, leaving a veil on their true physical nature. Aims. We explore the nature of 19 new GC candidates in the Galactic bulge by analysing their colour-magnitude diagrams (CMDs) in the near-infrared (NIR) using the VISTA Variables in the Via Láctea Survey (VVV) database. We estimate their main astrophysical parameters: reddening and extinction, distance, total luminosity, mean cluster proper motions (PMs), metallicity, and age. Methods. We obtain the cluster catalogues including the likely cluster members by applying a decontamination procedure on the observed CMDs based on the vector PM diagrams from VIRAC2. We adopt NIR reddening maps in order to calculate the reddening and extinction for each cluster, and then estimate the distance moduli and heliocentric distances. Metallicities and ages are evaluated by fitting theoretical stellar isochrones. We also calculate their luminosities in comparison with known Galactic GCs. Results. We estimate a wide reddening range of 0.25 ≤ E(J - Ks)≤2.0 mag and extinction 0.11 ≤ AKs ≤ 0.86 mag for the sample clusters, as expected in the bulge regions. The range of heliocentric distances is 6.8 ≤ D ≤ 11.4 kpc. This allows us to place these clusters between 0.56 and 3.25 kpc from the Galactic centre, assuming R⊙ = 8.2 kpc. Also, their PMs are kinematically similar to the typical motion of the Galactic bulge, apart from VVV-CL160, which shows different PMs. We also derive their metallicities and ages, finding -1.40≤ [Fe/H] ≤ 0.0 dex and t ≈ 8 - 13 Gyr respectively. The luminosities are calculated both in Ks- and V-bands, recovering -3.4 ≤ MV ≤ -7.5. We also examine the possible RR Lyrae members found in the cluster fields. Conclusions. Based on their positions, kinematics, metallicities, and ages, and comparing our results with the literature, we conclude that nine candidates are real GCs, seven need more observations to be fully confirmed as GCs, and three candidates are discarded as GCs and appear to be younger open clusters. © ESO 2022.Ítem New VVV Survey Globular Cluster Candidates in the Milky Way Bulge(Institute of Physics Publishing, 2017-11) Minniti, D.; Geisler, D.; Alonso-Garcia, J.; Palma, T.; Beamin, J.C.; Borissova, J.; Catelan, M.; Clariá, J.J.; Cohen, R.E.; Ramos, R.C.; Dias, B.; Fernández-Trincado, J.G.; Gómez, M.; Hempel, M.; Ivanov, V.D.; Kurtev, R.; Lucas, P.W.; Moni-Bidin, C.; Pullen, J.; Alegria, S.R.; Saito, R.K.; Valenti, E.It is likely that a number of Galactic globular clusters remain to be discovered, especially toward the Galactic bulge. High stellar density combined with high and differential interstellar reddening are the two major problems for finding globular clusters located toward the bulge. We use the deep near-IR photometry of the VISTA Variables in the Via Láctea (VVV) Survey to search for globular clusters projected toward the Galactic bulge, and hereby report the discovery of 22 new candidate globular clusters. These objects, detected as high density regions in our maps of bulge red giants, are confirmed as globular cluster candidates by their color-magnitude diagrams. We provide their coordinates as well as their near-IR color-magnitude diagrams, from which some basic parameters are derived, such as reddenings and heliocentric distances. The color-magnitude diagrams reveal well defined red giant branches in all cases, often including a prominent red clump. The new globular cluster candidates exhibit a variety of extinctions (0.06 < A Ks < 2.77) and distances (5.3 < D < 9.5 kpc). We also classify the globular cluster candidates into 10 metal-poor and 12 metal-rich clusters, based on the comparison of their color-magnitude diagrams with those of known globular clusters also observed by the VVV Survey. Finally, we argue that the census for Galactic globular clusters still remains incomplete, and that many more candidate globular clusters (particularly the low luminosity ones) await to be found and studied in detail in the central regions of the Milky Way.Ítem The globular cluster system of NGC 1316: III. Kinematic complexity(EDP Sciences, 2014-09) Richtler, T.; Hilker, M.; Kumar, B.; Bassino, L.P.; Gómez, M.; Dirsch, B.Context. The merger remnant NGC 1316 (Fornax A) is one of the most important objects regarding the investigation of and thus an important object to study merger-related processes. A recent photometric study used globular clusters in NGC 1316 to constrain its star formation history, but without the knowledge of individual radial velocities. The kinematical properties of the globular cluster system in comparison with the diffuse stellar light might give more insight into the formation of NGC 1316. Of particular interest is the dark matter content. Planetary nebulae in NGC 1316 indicate a massive dark halo, and globular cluster velocities provide inde pendent evidence. Aims. We aim at measuring radial velocities of globular clusters in NGC 1316. We use these kinematical data to investigate the global structure of NGC 1316 and to constrain the dark matter content. Methods. We perform multiobject spectroscopy with VLT/FORS2 and MXU. Out of 562 slits, we extract radial velocities for 177 globular clusters. Moreover, we measure radial velocities of the integrated galaxy light, using slits with a sufficiently bright sky. To these data, we add 20 cluster velocities from the literature. In an appendix, we identify new morphological features of NGC 1316 and its companion galaxy NGC 1317. Results. The GC sample based on radial velocities confirms the colour peaks already found in our photometric study. The bright clusters, which probably have their origin in a 2 Gyr old starburst and younger star formation events, avoid the systemic velocity. A Gaussian velocity distribution is found only for clusters fainter than about mR = 22 mag. The velocity distribution of clusters shows a pronounced peak at 1600 km s−1 . These clusters populate a wide area in the south-western region which we suspect to be a disk population. Globular clusters or subsamples of them do not show a clear rotation signal. This is different from the galaxy light, where rotation along the major axis is discernable out to 30 radius. The kinematic major axis of NGC 1316 is misaligned by about 10◦ with the photometric major axis, which might indicate a triaxial symmetry. A simple spherical model like that suggested by dynamical analyses of planetary nebulae also reproduces the velocity dispersions of the faint globular clusters. Conclusions. The central dark matter density of the present model resembles a giant elliptical galaxy. This contradicts population properties which indicate spiral galaxies as pre-merger components. Modified Newtonian dynamics (MOND) would provide a solu tion, but the kinematical complexity of NGC 1316 does not allow a really firm conclusion. However, NGC 1316 might anyway be a problem for a cold dark matter scenario, if the high dark matter density in the inner region is confirmed in future studies.Ítem The Globular Cluster System of NGC 5128: Ages, Metallicities, Kinematics, and Structural Parameters(2009) Woodley, K.A.; Gómez, M.Abstract: We review our recent studies of the globular cluster system of NGC 5128. First, we have obtained low-resolution, high signal-to-noise spectroscopy of 72 globular clusters using Gemini-S/GMOS to obtain the ages, metallicities, and the level of alpha enrichment of the metal-poor and metal-rich globular cluster subpopulations. Second, we have explored the rotational signature and velocity dispersion of the galaxy’s halo using over 560 globular clusters with radial velocity measurements. We have also compared the dependence of these properties on galactocentric distance and globular cluster age and metallicity. Using globular clusters as tracer objects, we have analyzed the mass, and M/L ratio of NGC 5128. Last, we have measured the structural parameters, such as half-light radii, of over 570 globular clusters from a superb 1.2 square degree Magellan/IMACS image. We will present the findings of these studies and discuss the connection to the formation and evolution of NGC 5128Ítem The globular cluster system of the nearest Seyfert II galaxy Circinus(2023-02) Obasi, C.; Gómez, M.; Minniti, D.; Alonso-García, J.; Hempel, M.; Pullen, J. B.; Gregg, M. D.; Baravalle, L. D.; Alonso, M. V.; Okere, B. I.Context. The globular cluster (GC) system of Circinus galaxy has not been probed previously partly because of the location of the galaxy at a- 3.8 Galactic latitude, which suffers severely from interstellar extinction, stellar crowding, and Galactic foreground contamination. However, the deep near-infrared (NIR) photometry by the VISTA Variables in the Via Láctea Extended Survey (VVVX) in combination with the precise astrometry of Gaia EDR3 allow us to map GCs in this region. Aims. Our long-term goal is to study and characterise the distributions of GCs and ultra-compact dwarfs in Circinus galaxy, which is the nearest Seyfert II galaxy. Here we conduct the first pilot search for GCs in this galaxy. Methods. We used NIR VVVX photometry in combination with Gaia EDR3 astrometric features, such as astrometric excess noise and the ratio of the sum of the blue photometer (BP) and red photometer (RP) to the broad G passband (BRexcess), to build the first homogeneous catalogue of GCs in Circinus galaxy. A robust combination of selection criteria allows us to effectively clean interlopers from our sample. Results We report the detection of a ¼70 GC candidates in this galaxy at a 3I confidence level. They show a bimodal colour distribution with the blue peak at (Ga- a- a- Ks)0 = 0.985±0.127 mag with a dispersion of 0.211±0.091 mag and the red peak at (Ga- a- a- Ks)0 = 1.625±0.177 mag with a dispersion of 0.482±0.114 mag. A GC specific frequency (Sa-N) of 1.3±0.2 was derived for the galaxy, and we estimated a total population of 120±40 GCs. Based on the projected radial distribution it appears that Circinus has a different distribution of GC candidates than MW and M 31. Conclusions. We demonstrate that Circinus galaxy hosts a sizeable number of cluster candidates. This result is the first leap towards understanding the evolution of old stellar clusters in this galaxy. © 2023 EDP Sciences. All rights reserved.Ítem The globular cluster system of the nearest Seyfert II galaxy Circinus(2023-02) Obasi, C.; Gómez, M.; Minniti, D.; Alonso-García, J.; Hempel, M.; Pullen, J. B.; Gregg, M. D.; Baravalle, L. D.; Alonso, M. V.; Okere, B. I.Context. The globular cluster (GC) system of Circinus galaxy has not been probed previously partly because of the location of the galaxy at a- 3.8 Galactic latitude, which suffers severely from interstellar extinction, stellar crowding, and Galactic foreground contamination. However, the deep near-infrared (NIR) photometry by the VISTA Variables in the Via Láctea Extended Survey (VVVX) in combination with the precise astrometry of Gaia EDR3 allow us to map GCs in this region. Aims. Our long-term goal is to study and characterise the distributions of GCs and ultra-compact dwarfs in Circinus galaxy, which is the nearest Seyfert II galaxy. Here we conduct the first pilot search for GCs in this galaxy. Methods. We used NIR VVVX photometry in combination with Gaia EDR3 astrometric features, such as astrometric excess noise and the ratio of the sum of the blue photometer (BP) and red photometer (RP) to the broad G passband (BRexcess), to build the first homogeneous catalogue of GCs in Circinus galaxy. A robust combination of selection criteria allows us to effectively clean interlopers from our sample. Results We report the detection of a ¼70 GC candidates in this galaxy at a 3I confidence level. They show a bimodal colour distribution with the blue peak at (Ga- a- a- Ks)0 = 0.985±0.127 mag with a dispersion of 0.211±0.091 mag and the red peak at (Ga- a- a- Ks)0 = 1.625±0.177 mag with a dispersion of 0.482±0.114 mag. A GC specific frequency (Sa-N) of 1.3±0.2 was derived for the galaxy, and we estimated a total population of 120±40 GCs. Based on the projected radial distribution it appears that Circinus has a different distribution of GC candidates than MW and M 31. Conclusions. We demonstrate that Circinus galaxy hosts a sizeable number of cluster candidates. This result is the first leap towards understanding the evolution of old stellar clusters in this galaxy. © 2023 EDP Sciences. All rights reserved.Ítem Unveiling the nature of 12 new low-luminosity Galactic globular cluster candidates(EDP Sciences, 2022-03-01) Garro, E.R.; Minniti, D.; Alessi, B.; Patchick, D.; Kronberger, M.; Alonso-García, J.; Fernández-Trincado, J.G.; Gómez, M.; Hempel, M.; Pullen, J.B.; Saito, R.K.; Ripepi, V.; Zelada Bacigalupo, R.Context. The Galactic globular cluster system is incompletely known, especially in the low-latitude regions of the Galactic bulge and disk. We report the physical characterisation of 12 star clusters in the Milky Way, most of which are explored here for the first time. Aims. Our primary aim is determining their main physical parameters, such as reddening, extinction, metallicity, age, total luminosity, mean cluster proper motions (PMs), and distances, in order to reveal the physical nature of these clusters. Methods. We study the clusters using optical and near-infrared (NIR) datasets. In particular, we use the Gaia Early Data Release 3 (EDR3) PMs in order to perform a PM decontamination procedure and build final catalogues with probable members. We match the Gaia EDR3 with the VISTA Variables in the Vía Láctea extended (VVVX) survey and the Two Micron All-Sky survey (2MASS) in the NIR, in order to construct complete NIR and optical colour-magnitude diagrams (CMDs) and investigate the clusters properties. Results. The extinctions are evaluated using existing reddening maps. We find ranges spanning 0:09. AKs. 0:86 mag and 0:89. AG. 4:72 mag in the NIR and optical, respectively. Adopting standard intrinsic red clump (RC) magnitudes and extinction values, we first obtain the distance modulus for each cluster and thereafter their heliocentric distances, which range from about 4 to 20 kpc. Therefore, we are able to place these clusters at 3. RG. 14 kpc from the Galactic centre. The best PARSEC isochrone fit yields a metallicity range of-1:8 < [Fe/H] < +0:3 and an approximate age range of 2 < age < 14 Gyr. Finally, we find that all clusters have low luminosities, with-6:9 < MV <-3:5 mag. Conclusions. Based on our photometric analysis, we find both open clusters (OCs) and globular clusters (GCs) in our sample. In particular, we confirm the OC nature for Kronberger 100, while we classify Patchick 125 as a metal-poor GC, Ferrero 54 as a metalrich GC, and ESO 92-18 as a possible old OC or young GC. The classification as GC candidates is also suggested for Kronberger 99, Patchick 122, Patchick 126, Riddle 15, FSR 190, and Gaia 2. We also conclude that Kronberger 119 and Kronberger 143 might be either old OCs or young GCs. © ESO 2022.Ítem VVVX-Gaia discovery of a low luminosity globular cluster in the Milky Way disk(EDP Sciences, 2020-10) Garro, E.R.; Minniti, D.; Gómez, M.; Alonso-García, J.; Barbá, R.H.; Barbuy, B.; Clariá, J.J.; Chené, A.N.; Dias, B.; Hempel, M.; Ivanov, V.D.; Lucas, P.W.Context. Milky Way globular clusters (GCs) are difficult to identify at low Galactic latitudes because of high differential extinction and heavy star crowding. The new deep near-infrared (IR) images and photometry from the VISTA Variables in the Via Láctea Extended Survey (VVVX) allow us to chart previously unexplored regions. Aims. Our long term aim is to complete the census of Milky Way GCs. The immediate goals are to estimate the astrophysical parameters for the newly discovered GC candidates, measuring their reddenings, extinctions, distances, total luminosities, proper motions, sizes, metallicities, and ages. Methods. We used the near-IR VVVX survey database, in combination with the optical photometry and proper motions (PMs) from Gaia Data Release 2 (DR2), and with the Two Micron All Sky Survey photometry to search for and characterise new GCs within the southern Galactic plane (|b| < 5°). Results. We report the detection of a heretofore unknown Galactic GC at RA = 14:09:00.0; Dec =-65:37:12 (J2000) corresponding to l = 310.828 deg; and b =-3.944 deg in galactic coordinates. We calculate a reddening of E(J-Ks) = (0.3 ± 0.03) mag and an extinction of AKs = (0.15 ± 0.01) mag for this new GC. Its distance modulus and corresponding distance were measured as (m-M) = (15.93 ± 0.03) mag and D = (15.5 ± 1.0) kpc, respectively. We also estimate the metallicity and age by comparison with known GCs and by fitting PARSEC and Dartmouth isochrones, finding [Fe/H] = (-0.70 ± 0.2) dex and t = (11.0 ± 1.0) Gyr. The mean GC PMs from Gaia DR2 are μα∗ = (-4.68 ± 0.47) mas yr-1 and μδ = (-1.34 ± 0.45) mas yr-1. The total luminosity of our cluster is estimated to be MKs = (-7.76 ± 0.5) mag. The core and tidal radii from the radial density profile are rc ∼ 2.1′ (4.6 pc) and rt = 6.5′ (14.6 pc) at the cluster distance. Conclusions. We have found a new low luminosity, old and metal-rich GC, situated in the far side of the Galactic disk at RG = 11.2 kpc from the Galactic centre and at z = 1.0 kpc below the plane. Interestingly, the location, metallicity, and age of this GC are coincident with the Monoceros ring structure. © 2020 ESO.