Browsing by Author "Hilker, M."

Now showing 1 - 16 of 16
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    Abundance ratios and IMF slopes in the dwarf elliptical galaxy NGC 1396 with MUSE
    (2016) Mentz, J. J.; La Barbera, F.; Peletier, R. F.; Falcon-Barroso, J.; Lisker, T.; van de Ven, G.; Loubser, S. I.; Hilker, M.; Sanchez-Janssen, R.; Napolitano, N.; Cantiello, M.; Capaccioli, M.; Norris, M.; Paolillo, M.; Smith, R.; Beasley, M. A.; Lyubenova, M.; Munoz, R.; Puzia, T.
    Deep observations of the dwarf elliptical (dE) galaxy NGC 1396 (M-V = -16.60, Mass similar to 4 x 10(8) M-circle dot), located in the Fornax cluster, have been performed with the Very Large Telescope/Multi Unit Spectroscopic Explorer spectrograph in the wavelength region from 4750 to 9350 angstrom. In this paper, we present a stellar population analysis studying chemical abundances, the star formation history (SFH) and the stellar initial mass function (IMF) as a function of galactocentric distance. Different, independent ways to analyse the stellar populations result in a luminosity-weighted age of similar to 6 Gyr and a metallicity [Fe/H]similar to -0.4, similar to other dEs of similar mass. We find unusually overabundant values of [Ca/Fe]similar to+0.1, and underabundant Sodium, with [Na/Fe] values around -0.1, while [Mg/Fe] is overabundant at all radii, increasing from similar to+0.1 in the centre to similar to+0.2 dex. We notice a significant metallicity and age gradient within this dwarf galaxy. To constrain the stellar IMF of NGC 1396, we find that the IMF of NGC 1396 is consistent with either a Kroupa-like or a top-heavy distribution, while a bottom-heavy IMF is firmly ruled out. An analysis of the abundance ratios, and a comparison with galaxies in the Local Group, shows that the chemical enrichment history of NGC 1396 is similar to the Galactic disc, with an extended SFH. This would be the case if the galaxy originated from a Large Magellanic Cloud-sized dwarf galaxy progenitor, which would lose its gas while falling into the Fornax cluster.
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    Dwarf Galaxies in Clusters
    (2003) Infante Lira, Leopoldo; Mieske, Steffen; Hilker, M.
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    Dynamical masses of ultra-compact dwarf galaxies in Fornax
    (2007) Hilker, M.; Infante Lira, Leopoldo
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    Extragalactic globular clusters in the near infrared - III. NGC 5846 and NGC 7192 - Quantifying the age distribution of sub-populations
    (2003) Hempel, M.; Hilker, M.; Kissler-Patig, M.; Puzia, T.H.; Minniti, D.; Goudfrooij, P.
    In this third paper of our series on near-IR and optical photometry of globular cluster systems in early-type galaxies we concentrate on the photometric results for NGC 5846 and NGC 7192, two group ellipticals, and on a first comparison between the globular cluster systems investigated so far. In NGC 5846 the colour-colour diagram shows clear bi-modality in (V - K), which is confirmed by a KMM test. The mean colour of both peaks were estimated to be (V - K)(blue) = 2.57 +/- 0.06 and (V - K)(red) = 3.18 +/- 0.06. The situation in NGC 7192 is different, in that the colour-colour diagram gives no evidence for a distinct second population of globular clusters. Using simulated colour distributions of globular cluster systems, we make a first step in quantifying the cumulative age distribution in globular cluster systems. Also here the result for NGC 5846 leads us to the conclusion that its metal-rich globular cluster population contains two globular cluster populations which differ in age by several Gyr. The age structure for NGC 7192 shows instead strong similarity with a single-age population.
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    Faint dwarf galaxies in Hickson Compact Group 90
    (2016) Ordenes, Y.; Taylor, M.; Puzia, Thomas H.; Muñoz Soria, Roberto; Eigenthaler, P.; Georgiev, I.; Goudfrooij, P.; Hilker, M.; Lancon, A.; Mamon, G.; Mieske, S.; Miller, B.; Peng, E.; Sanchez, R.
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    Faint Dwarf Spheroidals in the Fornax Cluster a Flat Luminosity Function
    (2003) Hilker, M.; Infante Lira, Leopoldo
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    Ngc 1427a - An Lmc Type Galaxy in the Fornax Cluster
    (1997) Hilker, M.; Infante Lira, Leopoldo
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    The curious case of the companion : evidence for cold accretion onto a dwarf satellite near the isolated elliptical NGC 7796
    (2018) Richtler, T.; Hilker, M.; Voggel, K.; Puzia, Thomas H.; Salinas, R.; Gómez, M.; Lane, R.
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    The first detection of ultra-diffuse galaxies in the Hydra I cluster from the VEGAS survey
    (2020) Iodice, E.; Cantiello, M.; Hilker, M.; Rejkuba, M.; Arnaboldi, M.; Spavone, M.; Greggio, L.; Forbes, D. A.; D’Ago, Giuseppe; Mieske, S.; Spiniello, C.; La Marca, A.; Rampazzo, R.; Paolillo, M.; Capaccioli, M.; Schipani, P.
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    The fornax cluster VLT spectroscopic survey - I. VIMOS spectroscopy of compact stellar systems in the fornax core region
    (2018) Pota, V.; Napolitano, N.R.; Hilker, M.; Spavone, M.; Schulz, C.; Cantiello, M.; Totora, C.; Lodice, C.; Paolillo, M.; Órdenes Briceño, Yasna
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    The globular cluster system of NGC 1316. IV. Nature of the star cluster complex SH2
    (2017) Richtler, T.; Husemann, B.; Hilker, M.; Puzia, Thomas H.; Bresolin, F.; Gómez, M.
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    The nature of UCDs
    (2008) Mieske, S.; Hilker, M.; Jordan, A.; Infante, L.; Kissler-Patig, M.; Rejkuba, M.; Richtler, T.; Cote, P.; Baumgardt, H.; West, M. J.; Ferrarese, L.; Peng, E. W.
    Context. The internal dynamics of ultra-compact dwarf galaxies (UCDs) has attracted increasing attention, with most of the UCDs studied to date located in the Virgo cluster.
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    The VISTA Variables in the Via Lactea extended (VVVX) ESO public survey: Completion of the observations and legacy
    (2024) Saito, R. K.; Hempel, M.; Alonso-Garcia, J.; Lucas, P. W.; Minniti, D.; Alonso, S.; Baravalle, L.; Borissova, J.; Caceres, C.; Chene, A. N.; Cross, N. J. G.; Duplancic, F.; Garro, E. R.; Gomez, M.; Ivanov, V. D.; Kurtev, R.; Luna, A.; Majaess, D.; Navarro, M. G.; Pullen, J. B.; Rejkuba, M.; Sanders, J. L.; Smith, L. C.; Albino, P. H. C.; Alonso, M. V.; Amores, E. B.; Angeloni, R.; Arias, J. I.; Arnaboldi, M.; Barbuy, B.; Bayo, A.; Beamin, J. C.; Bedin, L. R.; Bellini, A.; Benjamin, R. A.; Bica, E.; Bonatto, C. J.; Botan, E.; Braga, V. F.; Brown, D. A.; Cabral, J. B.; Camargo, D.; Garatti, Caratti O. A.; Carballo-Bello, J. A.; Catelan, M.; Chavero, C.; Chijani, M. A.; Claria, J. J.; Coldwell, G. V.; Pena, C. Contreras; Contreras Ramos, R.; Corral-Santana, J. M.; Cortes, C. C.; Cortes-Contreras, M.; Cruz, P.; Daza-Perilla, I. V.; Debattista, V. P.; Dias, B.; Donoso, L.; D'Souza, R.; Emerson, J. P.; Federle, S.; Fermiano, V.; Fernandez, J.; Fernandez-Trincado, J. G.; Ferreira, T.; Ferreira Lopes, C. E.; Firpo, V.; Flores-Quintana, C.; Fraga, L.; Froebrich, D.; Galdeano, D.; Gavignaud, I.; Geisler, D.; Gerhard, O. E.; Gieren, W.; Gonzalez, O. A.; Gramajo, L. V.; Gran, F.; Granitto, P. M.; Griggio, M.; Guo, Z.; Gurovich, S.; Hilker, M.; Jones, H. R. A.; Kammers, R.; Kuhn, M. A.; Kumar, M. S. N.; Kundu, R.; Lares, M.; Libralato, M.; Lima, E.; Maccarone, T. J.; Marchant Cortes, P.; Martin, E. L.; Masetti, N.; Matsunaga, N.; Mauro, F.; McDonald, I.; Mejias, A.; Mesa, V.; Milla-Castro, F. P.; Minniti, J. H.; Moni Bidin, C.; Montenegro, K.; Morris, C.; Motta, V.; Navarete, F.; Navarro Molina, C.; Nikzat, F.; Nilo Castellon, J. L.; Obasi, C.; Ortigoza-Urdaneta, M.; Palma, T.; Parisi, C.; Pena Ramirez, K.; Pereyra, L.; Perez, N.; Petralia, I.; Pichel, A.; Pignata, G.; Ramirez Alegria, S.; Rojas, A. F.; Rojas, D.; Roman-Lopes, A.; Rovero, A. C.; Saroon, S.; Schmidt, E. O.; Schroeder, A. C.; Schultheis, M.; Sgro, M. A.; Solano, E.; Soto, M.; Stecklum, B.; Steeghs, D.; Tamura, M.; Tissera, P.; Valcarce, A. A. R.; Valotto, C. A.; Vasquez, S.; Villalon, C.; Villanova, S.; Vivanco Cadiz, F.; Zelada Bacigalupo, R.; Zijlstra, A.; Zoccali, M.
    Context. The ESO public survey VISTA Variables in the Via Lactea (VVV) surveyed the inner Galactic bulge and the adjacent southern Galactic disk from 2009-2015. Upon its conclusion, the complementary VVV extended (VVVX) survey has expanded both the temporal as well as spatial coverage of the original VVV area, widening it from 562 to 1700 sq. deg., as well as providing additional epochs in JHKs filters from 2016-2023.