Browsing by Author "Zhang, Hong-Xin"

Now showing 1 - 7 of 7
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    A Radio Continuum Study of Dwarf Galaxies: 6 cm Imaging of LITTLE THINGS
    (2018) Hindson, Luke; Kitchener, Ged; Brinks, Elias; Heesen, Volker; Westcott, Jonathan; Hunter, Deidre; Zhang, Hong-Xin; Rupen, Michael; Rau, Urvashi
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    A Study of Two Dwarf Irregular Galaxies with Asymmetrical Star Formation Distributions
    (2018) Hunter, Deidre A.; Gallardo, Samavarti; Zhang, Hong-Xin; Adamo, Angela; Cook, David O.; Oh, Se-Heon; Elmegreen, Bruce G.; Kim, Hwihyun; Kahre, Lauren; Ubeda, Leonardo; Bright, Stacey N.; Ryon, Jenna E.; Fumagalli, Michele; Sacchi, Elena; Kennicutt, R. C.; Tosi, Monica; Dale, Daniel A.; Cignoni, Michele; Messa, Matteo; Grebel, Eva K.; Gouliermis, Dimitrios A.; Sabbi, Elena; Grasha, Kathryn; Gallagher, John S., III; Calzetti, Daniela; Lee, Janice C.
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    Erratum: The Next Generation Virgo Cluster Survey. X. Properties of Ultra-compact Dwarfs in the M87, M49, and M60 Regions
    (2015) Liu, Chengze; Peng, Eric W.; Côté, Patrick; Ferrarese, Laura; Jordán, Andrés J.; Mihos, J. Christopher; Zhang, Hong-Xin; Muñoz, Roberto P.; Puzia, Thomas H.; Lanço, Ariane
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    Lessons on Star-forming Ultra-diffuse Galaxies from the Stacked Spectra of the Sloan Digital Sky Survey
    (2020) Rong, Yu; Zhu, Kai; Johnston, Evelyn J.; Zhang, Hong-Xin; Cao, Tianwen; Puzia, Thomas H.; Galaz, Gaspar
    We investigate the on-average properties for 28 star-forming ultra-diffuse galaxies (UDGs) located in low-density environments, by stacking their spectra from the Sloan Digital Sky Survey. These relatively isolated UDGs, with stellar masses of log(10) (M-*/M-circle dot) similar to 8.57 +/- 0.29, have the on-average total stellar metallicity [M/H] similar to -0.82 +/- 0.14, iron metallicity [Fe/H] similar to -1.00 +/- 0.16, stellar age t(*) similar to 5.2 +/- 0.5 Gyr, alpha-enhancement [alpha/Fe] similar to 0.24 +/- 0.10, and oxygen abundance 12+log(O/H) similar to 8.16 +/- 0.06, as well as central stellar velocity dispersion 54 +/- 12 km s(-1). On the star formation rate versus stellar mass diagram, these UDGs are located lower than the extrapolated star-forming main sequence from the massive spirals, but roughly follow the main sequence of low-surface-brightness dwarf galaxies. We find that these star-forming UDGs are not particularly metal-poor or metal-rich for their stellar masses, as compared with the metallicity-mass relations of the nearby typical dwarfs. With the UDG data of this work and previous studies, we also find a coarse correlation between [Fe/H] and magnesium-element enhancement [Mg/Fe] for UDGs: [Mg/Fe] similar or equal to -0.43(+/- 0.26) [Fe/H] -0.14(+/- 0.40).
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    The most massive ultra-compact dwarf galaxy in the virgo cluster
    (2015) Liu, Chengze; Peng, Eric W.; Toloba, Elisa; Christopher Mihos, J.; Ferrarese, Laura; Álamo Martínez, Karla; Zhang, Hong-Xin; Côté, Patrick; Cuillandre, Jean-Charles; Puzia, Thomas H.
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    The Next Generation Virgo Cluster Survey (NGVS). XXXI. The Kinematics of Intracluster Globular Clusters in the Core of the Virgo Cluster
    (2018) Longobardi, Alessia; Peng, Eric W.; Cote, Patrick; Mihos, J. Christopher; Ferrarese, Laura; Puzia, Thomas H.; Lancon, Ariane; Zhang, Hong-Xin; Munoz, Roberto P.; Blakeslee, John P.; Guhathakurta, Puragra; Durrell, Patrick R.; Sanchez-Janssen, Ruben; Toloba, Elisa; Jordán Colzani, Andrés Cristóbal; Eyheramendy Duerr, Susana; Cuillandre, Jean-Charles; Gwyn, Stephen D. J.; Boselli, Alessandro; Duc, Pierre-Alain; Liu, Chengze; Alamo-Martinez, Karla; Powalka, Mathieu; Lim, Sungsoon
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    The Next Generation Virgo Cluster Survey. XVII. A Search for Planetary Nebulae in Virgo Cluster Globular Clusters
    (2019) Sun, Weijia; Peng, Eric W.; Ko, Youkyung; Cote, Patrick; Ferrarese, Laura; Lee, Myung Gyoon; Liu, Chengze; Longobardi, Alessia; Chilingarian, Igor V.; Spengler, Chelsea; Zabludoff, Ann I.; Zhang, Hong-Xin; Cuillandre, Jean-Charles; Gwyn, Stephen D. J.
    The occurrence of planetary nebulae (PNe) in globular clusters (GCs) provides an excellent chance to study lowmass stellar evolution in a special (low-metallicity, high stellar density) environment. We report a systematic spectroscopic survey for the [O III] 5007 angstrom emission line of PNe in 1469 Virgo GCs and 121 Virgo ultra-compact dwarfs (UCDs), mainly hosted in the giant elliptical galaxies M87, M49, M86, and M84. We detected zero PNe in our UCD sample and discovered one PN (M-5007 = -4.1 mag) associated with an M87 GC. We used the [O III] detection limit for each GC to estimate the luminosity-specific frequency of PNe, a, and measured a in the Virgo cluster GCs to be alpha similar to 3.9(-0.7)(+5.2) x 10(-8) PN/(circle dot). The value of a in the Virgo GCs is among the lowest reported in any environment, due in part to the large sample size, and it is 5-6 times lower than that for the Galactic GCs. We suggest that a decreases toward brighter and more massive clusters, sharing a similar trend as the binary fraction, and the discrepancy between the Virgo and Galactic GCs can be explained by the observational bias in extragalactic surveys toward brighter GCs. This low but nonzero efficiency in forming PNe may highlight the important role played by binary interactions in forming PNe in GCs. We argue that a future survey of less massive Virgo GCs will be able to determine whether PN production in the Virgo GCs is governed by an internal process (mass, density, binary fraction) or if it is largely regulated by the external environment.