Browsing by Author "Marconi, M."

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    High resolution spectroscopic analysis of seven giants in the bulge globular cluster NGC 6723
    (2016) Rojas Arriagada, A.; Zoccali, Manuela; Vásquez Godoy, Sergio Osmán; Ripepi, V.; Musella, I.; Marconi, M.; Grado, A.; Limatola, L.
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    Near-infrared observations of RR Lyrae and Type II Cepheid variables in the metal-rich bulge globular cluster NGC 6441
    (2022) Bhardwaj, A.; Kanbur, S. M.; Rejkuba, M.; Marconi, M.; Catelan, Márcio; Ripepi, V.; Singh, H. P.
    Context. NGC 6441 is a bulge globular cluster (GC) with an unusual horizontal branch morphology and a rich population of RR Lyrae (RRL) and Type II Cepheid (T2C) variables that is unexpected for its relatively high metallicity. Aims: Our goal is to characterize the pulsation properties of the population II RRL and T2C variables in this metal-rich GC and compare them with a sample of variables in more metal-poor clusters, as well as with theoretical predictions. Methods: We present JHKs time-series observations of 42 RRLs, eight T2Cs, and ten eclipsing binary candidate variables in NGC 6441 . The multi-epoch observations were obtained using the FLAMINGOS-2 instrument on the 8-m Gemini South telescope. Multiband data are used to investigate pulsation properties of the RRL and T2C variables, including their light curves, instability strip, period-amplitude diagrams, and period-luminosity and period-Wesenheit relations (PLRs and PWRs) in the JHKs filters. Results: The near-infrared (NIR) pulsation properties of RRL variables are well fitted with theoretical models that have canonical helium content and the mean-metallicity of NGC 6441 ([Fe/H] = −0.44 ± 0.07 dex). The helium-enhanced RRL models predict brighter NIR magnitudes and bluer colors than the observations of RRL in the cluster. We find that the empirical slopes of the RRL PLRs and PWRs in NGC 6441 are statistically consistent with those of RRLs in more metal-poor GCs, as well as the theoretical models. Therefore, we use theoretical calibrations of RRL period-luminosity-metallicity (PLZ) relations to simultaneously estimate the mean reddening, E(J − Ks)=0.26 ± 0.06 mag, and the distance, d = 12.67 ± 0.09 kpc, to NGC 6441. Our mean reddening value is consistent with an independent estimate from the bulge reddening map based on red clump stars. The RRL-based distance agrees well with similar literature measurements based on the PLZ relations, and the Gaia and other independent methods. Our distance and reddening values provide a very good agreement between the PLRs of T2Cs in NGC 6441 and those for RRLs and T2Cs in Galactic GCs that span a broad range of metallicity. Conclusions: We conclude that the NIR colour-magnitude diagrams, pulsation properties, and PLRs for RRLs and T2Cs in NGC 6441 are in good agreement with the predictions of RRL pulsation models with canonical helium content. This suggests that these population II variables are either not significantly helium enhanced, as previously thought, or the impact of such enhancement is smaller in NIR than the predictions of the pulsation models. Full Table 2 is only available at the CDS via anonymous ftp to https://cdsarc.cds.unistra.fr (ftp://130.79.128.5) or via https://cdsarc.cds.unistra.fr/viz-bin/cat/J/A+A/668/A59...
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    New near-infrared JHKs light-curve templates for RR Lyrae variables
    (2019) Braga, V. F.; Stetson, P. B.; Bono, G.; Dall'Ora, M.; Ferraro, I; Fiorentino, G.; Iannicola, G.; Inno, L.; Marengo, M.; Neeley, J.; Beaton, R. L.; Buonanno, R.; Calamida, A.; Ramos, R. Contreras; Chaboyer, B.; Fabrizio, M.; Freedman, W. L.; Gilligan, C. K.; Johnston, K., V; Lub, J.; Madore, B. F.; Magurno, D.; Marconi, M.; Marinoni, S.; Marrese, P. M.; Mateo, M.; Matsunaga, N.; Minniti, D.; Monson, A. J.; Monelli, M.; Nonino, M.; Persson, S. E.; Pietrinferni, A.; Sneden, C.; Storm, J.; Walker, A. R.; Valenti, E.; Zoccali, M.
    We provide homogeneous optical (UBVRI) and near-infrared (NIR, JHK) time series photometry for 254 cluster (omega Cen, M 4) and field RR Lyrae (RRL) variables. We ended up with more than 551 000 measurements, of which only 9% are literature data. For 94 fundamental (RRab) and 51 first overtones (RRc) we provide a complete optical/NIR characterization (mean magnitudes, luminosity amplitudes, epoch of the anchor point). The NIR light curves of these variables were adopted to provide new light-curve templates for both RRc and RRab variables. The templates for the J and the H bands are newly introduced, together with the use of the pulsation period to discriminate among the different RRab templates. To overcome subtle uncertainties in the fit of secondary features of the light curves we provide two independent sets of analytical functions (Fourier and periodic Gaussian series). The new templates were validated by using 26 omega Cen and Bulge RRLs. We find that the difference between the measured mean magnitude along the light curve and the mean magnitude estimated by using the template on a single randomly extracted phase point is better than 0.01 mag (sigma = 0.04 mag). We also validated the template on variables for which at least three phase points were available, but without information on the phase of the anchor point. We find that the accuracy of the mean magnitudes is also similar to 0.01 mag (sigma = 0.04 mag). The new templates were applied to the Large Magellanic Cloud (LMC) globular cluster Reticulum and by using literature data and predicted PLZ relations we find true distance moduli mu = 18.47 +/- 0.10 (rand.) +/- 0.03 (syst.) mag (J) and 18.49 +/- 0.09 +/- 0.05 mag (K). We also used literature optical and mid-infrared data and we found a mean mu of 18.47 +/- 0.02 +/- 0.06 mag, suggesting that Reticulum is similar to 1 kpc closer than the LMC.
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    On the RR Lyrae Stars in Globulars. V. The Complete Near-infrared (JHKs) Census of ω Centauri RR Lyrae Variables
    (2018) Braga, V.F.; Stetson, P.B.; Bono, G.; Dall ’Ora, M.; Ferraro, I.; Fiorentino, G.; Iannicola, G.; Marconi, M.; Minniti, D.; Zoccali, Manuela
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    RR Lyrae stars in M31 globular clusters: B514
    (2008) Contreras, R.; Federici, L.; Clementini, G.; Cacciari, C.; Merighi, R.; Kinemuchi, K.; Catelan , Marcio; Fusi Pecci, F.; Marconi, M.; Pritzl, B.; Smith, H.
    We present preliminary results of a variable star search in the metal-poor globular cluster B514 of the Andromeda galaxy (M31), based on Hubble Space Telescope Wide Field Planetary Camera 2 and Advanced Camera for Surveys observations. A large number of RR Lyrae stars have been identified for the first time in a globular cluster of M31. The average period of the RR Lyrae variables (< Pab > = 0.58 days and < Pc > = 0.35 days, for fundamental-mode and first-overtone pulsators, respectively) and the position in the period-amplitude diagram both suggest that B514 is likely an Oosterhoff I cluster, contrary to the general behaviour of the metal-poor globular clusters in the Milky Way, which show instead Oosterhoff type II pulsation properties....
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    Sensitivity of the Cherenkov Telescope Array to spectral signatures of hadronic PeVatrons with application to Galactic Supernova Remnants
    (2023) Acero, F.; Acharyya, A.; Adam, R.; Aguasca-Cabot, A.; Agudo, I.; Aguirre-Santaella, A.; Alfaro, J.; Aloisio, R.; Crespo, N. Alvarez; Batista, R. Alves; Amati, L.; Amato, E.; Ambrosi, G.; Anguner, E. O.; Aramo, C.; Arcaro, C.; Armstrong, T.; Asano, K.; Ascasibar, Y.; Aschersleben, J.; Backes, M.; Baktash, A.; Balazs, C.; Balbo, M.; Ballet, J.; Larriva, A. Baquero; Martins, V. Barbosa; Barres de Almeida, U.; Barrio, J. A.; Bastieri, D.; Baxter, J. R.; Tjus, J. Becker; Benbow, W.; Bernardos-Martin, M. I.; Bernete, J.; Berti, A.; Bertucci, B.; Beshley, V.; Bhattacharjee, P.; Bhattacharyya, S.; Biland, A.; Bissaldi, E.; Biteau, J.; Blanch, O.; Bordas, P.; Bottacini, E.; Bregeon, J.; Brose, R.; Bucciantini, N.; Bulgarelli, A.; Capasso, M.; Dolcetta, R. A. Capuzzo; Caraveo, P.; Cardillo, M.; Carosi, R.; Casanova, S.; Cascone, E.; Cassol, F.; Catalani, F.; Cerruti, M.; Chadwick, P.; Chaty, S.; Chen, A.; Chernyakova, M.; Chiavassa, A.; Chudoba, J.; Coimbra-Araujo, C.; Conforti, V.; Contreras, J. L.; Costa, A.; Costantini, H.; Cristofari, P.; Crocker, R.; D'Amico, G.; D'Ammando, F.; De Angelis, A.; De Caprio, V.; Pino, E. M. de Gouveia Dal; Wilhelmi, E. de Ona; de Souza, V.; Delgado, C.; della Volp, D.; Depaoli, D.; Di Girolamo, T.; Di Pierro, F.; Di Tria, R.; Di Venere, L.; Diebold, S.; Djuvsland, J. I.; Donini, A.; Doro, M.; Dos Anjos, R. d. C.; Dwarkadas, V. V.; Einecke, S.; Elsaesser, D.; Emery, G.; Evoli, C.; Falceta-Goncalves, D.; Fedorova, E.; Fegan, S.; Ferrand, G.; Fiandrini, E.; Filipovic, M.; Fioretti, V.; Fiori, M.; Foffano, L.; Fontaine, G.; Fukami, S.; Galanti, G.; Galaz, G.; Gammaldi, V.; Gasbarra, C.; Ghalumyan, A.; Ghirlanda, G.; Giarrusso, M.; Giavitto, G.; Giglietto, N.; Giordano, F.; Giroletti, M.; Giuliani, A.; Giunti, L.; Godinovic, N.; Coelho, J. Goulart; Greaux, L.; Green, D.; Grondin, M. -H.; Gueta, O.; Gunji, S.; Hassan, T.; Heller, M.; Hernandez-Cadena, S.; Hinton, J.; Hnatyk, B.; Hnatyk, R.; Hoffmann, D.; Hofmann, W.; Holder, J.; Horan, D.; Horvath, P.; Hrabovsky, M.; Hrupec, D.; Inada, T.; Incardona, F.; Inoue, S.; Ishio, K.; Jamrozy, M.; Janecek, P.; Martinez, I. Jimenez; Jin, W.; Jung-Richardt, I.; Jurysek, J.; Kaaret, P.; Karas, V.; Katz, U.; Kerszberg, D.; Khelifi, B.; Kieda, D. B.; Kissmann, R.; Kleiner, T.; Kluge, G.; Kluzniak, W.; Knodlseder, J.; Kobayashi, Y.; Kohri, K.; Komin, N.; Kornecki, P.; Kubo, H.; La Palombara, N.; Lainez, M.; Lamastra, A.; Lapington, J.; Lemoine-Goumard, M.; Lenain, J. -P.; Leone, F.; Leto, G.; Leuschner, F.; Lindfors, E.; Liodakis, I.; Lohse, T.; Lombardi, S.; Longo, F.; Lopez-Coto, R.; Lopez-Moya, M.; Lopez-Oramas, A.; Loporchio, S.; Luque-Escamilla, P. L.; Macias, O.; Mackey, J.; Majumdar, P.; Mandat, D.; Manganaro, M.; Manico, G.; Marconi, M.; Marti, J.; Martinez, G.; Martinez, M.; Martinez, O.; Mello, A. J. T. S.; Menchiari, S.; Meyer, D. M. -A.; Micanovic, S.; Miceli, D.; Miceli, M.; Michalowski, J.; Miener, T.; Miranda, J. M.; Mitchell, A.; Mode, B.; Moderski, R.; Mohrmann, L.; Molina, E.; Montaruli, T.; Morcuende, D.; Morlino, G.; Morselli, A.; Mose, M.; Moulin, E.; Mukherjee, R.; Munari, K.; Murach, T.; Nagai, A.; Nagataki, S.; Nemmen, R.; Niemiec, J.; Nieto, D.; Nievas Rosillo, M.; Nikolajuk, M.; Nishijima, K.; Noda, K.; Novosyadlyj, B.; Nozaki, S.; Ohishi, M.; Ohm, S.; Ohtani, Y.; Okumura, A.; Olmi, B.; Ong, R. A.; Orienti, M.; Orito, R.; Orlandini, M.; Orlando, E.; Orlando, S.; Ostrowski, M.; Oya, I.; Pantaleo, F. R.; Paredes, J. M.; Patricelli, B.; Pecimotika, M.; Peresano, M.; Perez-Romero, J.; Persic, M.; Petruk, O.; Piano, G.; Pietropaolo, E.; Pirola, G.; Pittori, C.; Pohl, M.; Ponti, G.; Prandini, E.; Principe, G.; Priyadarshi, C.; Pueschel, E.; Puehlhofer, G.; Pumo, M. L.; Quirrenbach, A.; Rando, R.; Razzaque, S.; Reichherzer, P.; Reimer, A.; Reimer, O.; Renaud, M.; Reposeur, T.; Ribo, M.; Richtler, T.; Rico, J.; Rieger, F.; Rigoselli, M.; Riitano, L.; Rizi, V.; Roache, E.; Romano, P.; Romeo, G.; Rosado, J.; Rowell, G.; Rudak, B.; Sadeh, I.; Safi-Harb, S.; Saha, L.; Sailer, S.; Sanchez-Conde, M.; Sarkar, S.; Satalecka, K.; Saturni, F. G.; Scherer, A.; Schovanek, P.; Schussler, F.; Schwanke, U.; Scuderi, S.; Seglar-Arroyo, M.; Sergijenko, O.; Servillat, M.; Shang, R. -Y.; Sharma, P.; Siejkowski, H.; Sliusar, V.; Slowikowska, A.; Sol, H.; Specovius, A.; Spencer, S. T.; Spengler, G.; Stamerra, A.; Stanic, S.; Starecki, T.; Starling, R.; Stolarczyk, T.; Stuani Pereira, L. A.; Suda, Y.; Suomijarvi, T.; Sushch, I.; Tajima, H.; Tam, P. -H. T.; Tanaka, S. J.; Tavecchio, F.; Testa, V.; Tian, W.; Tibaldo, L.; Torres, D. F.; Tothill, N.; Vallage, B.; Vallania, P.; van Eldik, C.; van Scherpenberg, J.; Vandenbroucke, J.; Vazquez Acosta, M.; Vecchi, M.; Vercellone, S.; Verna, G.; Viana, A.; Vignatti, J.; Vitale, V.; Vodeb, V.; Vorobiov, S.; Vuillaume, T.; Wagner, S. J.; Walter, R.; White, M.; Wierzcholska, A.; Will, M.; Williams, D.; Yang, L.; Yoshida, T.; Yoshikoshi, T.; Zaharijas, G.; Zampieri, L.; Zavrtanik, D.; Zavrtanik, M.; Zhdanov, V. I.; Zivec, M.
    The local Cosmic Ray (CR) energy spectrum exhibits a spectral softening at energies around 3 PeV. Sources which are capable of accelerating hadrons to such energies are called hadronic PeVatrons. However, hadronic PeVatrons have not yet been firmly identified within the Galaxy. Several source classes, including Galactic Supernova Remnants (SNRs), have been proposed as PeVatron candidates. The potential to search for hadronic PeVatrons with the Cherenkov Telescope Array (CTA) is assessed. The focus is on the usage of very high energy y-ray spectral signatures for the identification of PeVatrons. Assuming that SNRs can accelerate CRs up to knee energies, the number of Galactic SNRs which can be identified as PeVatrons with CTA is estimated within a model for the evolution of SNRs. Additionally, the potential of a follow-up observation strategy under moonlight conditions for PeVatron searches is investigated. Statistical methods for the identification of PeVatrons are introduced, and realistic Monte-Carlo simulations of the response of the CTA observatory to the emission spectra from hadronic PeVatrons are performed. Based on simulations of a simplified model for the evolution for SNRs, the detection of a y-ray signal from in average 9 Galactic PeVatron SNRs is expected to result from the scan of the Galactic plane with CTA after 10 h of exposure. CTA is also shown to have excellent potential to confirm these sources as PeVatrons in deep observations with O(100) hours of exposure per source.
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    Stellar populations of the newly discovered satellites of the Milky Way .
    (2008) Dall'Ora, M.; Clementini, G.; Ripepi, V.; Kinemuchi, K.; Greco, C.; Kuehn, C.; Musella, I.; Rodgers, C. T.; Di Fabrizio, L.; Beers, T. C.; Catelan, Marcio; Marconi, M.; Pritzl, B. J.; Smith., H. A.
    We have carried out an extensive observing campaign on the new dwarf spheroidal galaxies (dSphs) recently discovered by the SDSS, with the aim of characterizing their stellar populations and structural properties, as well as their variable star content. First preliminary results are presented for the Canes Venatici II, the Coma and the Ursa Major II dSphs, based on data collected at a variety of telescopes, and reaching each galaxy's Main Sequence Turn-Off (MSTO)....
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    unVEil the darknesS of The gAlactic buLgE (VESTALE)
    (2018) Bono, G.; Dall'Ora, M.; Fabrizio, M.; Crestani, J.; Braga, V. F.; Fiorentino, G.; Altavilla, G.; Botticella, M. T.; Calamida, A.; Castellani, M.; Catelan, Marcio; Chaboyer, B.; Chiappini, C.; Clarkson, W.; Contreras Ramos, R.; Creevey, O.; da Silva, R.; Debattista, V.; Degl'Innocenti, S.; Ferraro, I.; Gilligan, C. K.; Gonzalez, O.; Hambleton, K.; Iannicola, G.; Inno, L.; Kunder, A.; Lemasle, B.; Magrini, L.; Magurno, D.; Marconi, M.; Marengo, M.; Marinoni, S.; Marrese, P. M.; Martinez-Vazquez, C. E.; Matsunaga, N.; Monelli, M.; Prada Moroni, P. G.; Musella, I.; Navarro, M. G.; Neeley, J.; Nonino, M.; Pietrinferni, A.; Pulone, L.; Rich, M. R.; Ripepi, V.; Sacco, G.; Saha, A.; Salaris, M.; Sneden, C.; Stetson, P. B.; Street, R. A; Szabo, R.; Tantalo, M.; Tognelli, E.; Torelli, M.; Valenti, E.; Walker, A. R.; Zoccali, M.
    The main aim of this experiment is to provide a complete census of old (t > 10 Gyr, RR Lyrae, type II Cepheids, red horizontal branch), intermediate age (red clump, Miras) and young (classical Cepheids) stellar tracers across the Galactic Bulge. To fully exploit the unique photometric quality of LSST images, we plan to perform a Shallow minisurvey (ugrizy, -20 < l < 20 deg, -15 < b < 10 deg) and a Deep minisurvey (izy, -20 < l < 20 deg, -3 < b < 3 deg). The former one is aimed at constraining the 3D structure of the galactic Bulge across the four quadrants, and in particular, the transition between inner and outer Bulge. The u,g,r,i,z,y LSST bands provide fundamental diagnostics to constrain the evolutionary properties of low and intermediate-mass stars when moving from a metal-poor to a metal-rich regime. The deep minisurvey is aimed at tracing RR Lyrae, Red Clump stars, Miras and classical Cepheids in highly reddened regions of the Galactic center. These images will allow us to investigate the role that baryonic mass and dark matter played in the early formation and evolution of the MW....
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    Using classical cepheids to study the far side of the milky way disk : I. Spectroscopic classification and the metallicity gradient
    (2020) Minniti, Javier Horacio; Sbordone, L.; Rojas Arriagada, A.; Zoccali, Manuela; Contreras Ramos, Rodrigo Andrés; Minniti, D.; Marconi, M.; Braga, V. F.; Catelan, Márcio; Duffau, S.; Gieren Waiblinger, Wolfgang Paul; Valcarce Bravo, Aldo Alfonso Raúl
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    Using classical Cepheids to study the far side of the Milky Way disk II. The spiral structure in the first and fourth Galactic quadrants
    (2021) Minniti, J. H.; Zoccali, M.; Rojas-Arriagada, A.; Minniti, D.; Sbordone, L.; Ramos, R. Contreras; Braga, V. F.; Catelan, M.; Duffau, S.; Gieren, W.; Marconi, M.; Valcarce, A. A. R.
    In an effort to improve our understanding of the spiral arm structure of the Milky Way, we use classical Cepheids (CCs) to increase the number of young tracers on the far side of the Galactic disk with accurately determined distances. We used a sample of 30 CCs that were discovered using near-infrared photometry from the VISTA Variables in the Via Lactea survey (VVV) and classified based on their radial velocities and metallicities. We combined them with another 20 CCs from the literature for which VVV photometry is available. We used the compiled sample of CCs with homogeneously computed distances based on VVV infrared photometry as a proof of concept to trace the spiral structure in the poorly explored far side of the disk. Although the use of CCs has some caveats, these variables are currently the only available young tracers on the far side of the disk for which a numerous sample with accurate distances can be obtained. Therefore, a larger sample could allow us to make a significant step forward in our understanding of the Milky Way disk as a whole. We present preliminary evidence that CCs favor the following: a spiral arm model with two main arms (Perseus and Scutum-Centaurus) that branch out into four arms at Galactocentric distances, R-GC >= 5-6 kpc; the extension of the Scutum-Centaurus arm behind the Galactic center; and a possible connection between the Perseus arm and the Norma tangency direction. The current sample of CCs on the far side of the Galaxy are in the mid-plane, which argues against the presence of a severely warped disk at small Galactocentric distances (R-GC <= 12 kpc) in the studied area. The discovery and characterization of CCs at near-infrared wavelengths appears to be a promising tool to complement studies based on other spiral arm tracers and extend them to the far side of our Galaxy.