Browsing by Author "Liu, Chengze"

Now showing 1 - 17 of 17
  • Thumbnail Image
    Item
    A GEMINI/GMOS STUDY OF INTERMEDIATE LUMINOSITY EARLY-TYPE VIRGO CLUSTER GALAXIES. I. GLOBULAR CLUSTER AND STELLAR KINEMATICS
    (2015) Li, Biao; Peng, Eric W.; Zhang, Hong-xin; Blakeslee, John P.; Côté, Patrick; Ferrarese, Laura; Jordán Colzani, Andrés Cristóbal; Liu, Chengze; Mei, Simona; Puzia, Thomas H.
  • No Thumbnail Available
    Item
    An evolutionary continuum from nucleated dwarf galaxies to star clusters
    (2023) Wang, Kaixiang; Peng, Eric W.; Liu, Chengze; Mihos, J. Christopher; Cote, Patrick; Ferrarese, Laura; Taylor, Matthew A.; Blakeslee, John P.; Cuillandre, Jean-Charles; Duc, Pierre-Alain; Guhathakurta, Puragra; Gwyn, Stephen; Ko, Youkyung; Lancon, Ariane; Lim, Sungsoon; Macarthur, Lauren A.; Puzia, Thomas; Roediger, Joel; Sales, Laura V.; Sanchez-Janssen, Ruben; Spengler, Chelsea; Toloba, Elisa; Zhang, Hongxin; Zhu, Mingcheng
    Systematic studies1-4 have revealed hundreds of ultra-compact dwarf galaxies (UCDs5) in the nearby Universe. With half-light radii rh of approximately 10-100 parsecs and stellar masses M* approximate to 106-108 solar masses, UCDs are among the densest known stellar systems6. Although similar in appearance to massive globular clusters7, the detection of extended stellar envelopes4,8,9, complex star formation histories10, elevated mass-to-light ratio11,12 and supermassive black holes13-16 suggest that some UCDs are remnant nuclear star clusters17 of tidally stripped dwarf galaxies18,19, or even ancient compact galaxies20. However, only a few objects have been found in the transient stage of tidal stripping21,22, and this assumed evolutionary path19 has never been fully traced by observations. Here we show that 106 galaxies in the Virgo cluster have morphologies that are intermediate between normal, nucleated dwarf galaxies and single-component UCDs, revealing a continuum that fully maps this morphological transition and fills the 'size gap' between star clusters and galaxies. Their spatial distribution and redder colour are also consistent with stripped satellite galaxies on their first few pericentric passages around massive galaxies23. The 'ultra-diffuse' tidal features around several of these galaxies directly show how UCDs are forming through tidal stripping and that this evolutionary path can include an early phase as a nucleated ultra-diffuse galaxy24,25. These UCDs represent substantial visible fossil remnants of ancient dwarf galaxies in galaxy clusters, and more low-mass remnants probably remain to be found.
  • Thumbnail Image
    Item
    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
  • No Thumbnail Available
    Item
    Fresh Insights on the Kinematics of M49's Globular Cluster System with MMT/Hectospec Spectroscopy
    (2021) Taylor, Matthew A.; Ko, Youkyung; Cote, Patrick; Ferrarese, Laura; Peng, Eric W.; Zabludoff, Ann; Roediger, Joel; Sanchez-Janssen, Ruben; Hendel, David; Chilingarian, Igor; Liu, Chengze; Spengler, Chelsea; Zhang, Hongxin
    We present the first results of an MMT/Hectospec campaign to measure the kinematics of globular clusters (GCs) around M49-the brightest galaxy in the Virgo galaxy cluster, which dominates the Virgo B subcluster. The data include kinematic tracers beyond 95 kpc (similar to 5.2 effective radii) for M49 for the first time, enabling us to achieve three key insights reported here. First, beyond similar to 20 '-30 ' (similar to 100-150 kpc), the GC kinematics sampled along the minor photometric axis of M49 become increasingly hotter, indicating a transition from GCs related to M49 to those representing the Virgo B intra-cluster medium. Second, there is an anomaly in the line-of-sight radial velocity dispersion (sigma ( r,los)) profile in an annulus similar to 10-15 ' (similar to 50-90 kpc) from M49 in which the kinematics cool by Delta sigma ( r,los) approximate to 150 km s(-1) relative to those in- or outward. The kinematic fingerprint of a previous accretion event is hinted at in projected phase-space, and we isolate GCs that both give rise to this feature, and are spatially co-located with two prominent stellar shells in the halo of M49. Third, we find a subsample of GCs with velocities representative of the dwarf galaxy VCC 1249 that is currently interacting with M49. The spatial distribution of these GCs closely resembles the morphology of VCC 1249's isophotes, indicating that several of these GCs are likely in the act of being stripped from the dwarf during its passage through M49's halo. Taken together, these results point toward the opportunity of witnessing ongoing giant halo assembly in the depths of a cluster environment.
  • Thumbnail Image
    Item
    New constraints on a complex relation between globular cluster colors and environment
    (2016) Powalka, Mathieu; Puzia, Thomas H.; Lançon, Ariane; Peng, Eric W.; Schönebeck, Frederik; Alamo Martínez, Karla; Ángel Ángel, Simón Andrés; Blakeslee, John P.; Côté, Patrick; Cuillandre, Jean-Charles; Duc, Pierre-Alain; Durrell, Patrick; Ferrarese, Laura; Grebel, Eva K.; Guhathakurta, Puragra; Gwyn, S. D. J.; Kuntschner, Harald; Lim, Sungsoon; Liu, Chengze; Lyubenova, Mariya
  • Thumbnail Image
    Item
    Stellar population properties of ultracompact dwarfs in M87 : a mass-metallicity correlation connecting low-metallicity globular clusters and compact ellipticals
    (2018) Zhang, Hong Xin; Puzia, Thomas H.; Peng, Eric W.; Liu, Chengze; Coté, Patrick; Ferrarese, Laura; Duc, Pierre Alain; Eigenthaler, Paul; Lim, Sungsoon; Muñoz, Roberto P.
  • No Thumbnail Available
    Item
    The Color Gradients of the Globular Cluster Systems in M87 and M49
    (2022) Wu, Yiming; Liu, Chengze; Peng, Eric W.; Ko, Youkyung; Cote, Patrick; Jain, Rashi; Ferrarese, Laura; Yang, Xiaohu; Lancon, Ariane; Puzia, Thomas; Lim, Sungsoon
    Combining data from the ACS Virgo Cluster Survey and the Next Generation Virgo cluster Survey, we extend previous studies of color gradients of the globular cluster (GC) systems of the two most massive galaxies in the Virgo cluster, M87 and M49, to radii of similar to 15 R (e) (similar to 200 kpc for M87 and similar to 250 kpc for M49, where R (e) is the effective radius). We find significant negative color gradients, i.e., becoming bluer with increasing distance, out to these large radii. The gradients are driven mainly by the outward decrease in the ratio of red to blue GC numbers. The color gradients are also detected out to similar to 15 R (e) in the red and blue subpopulations of GCs taken separately. In addition, we find a negative color gradient when we consider the satellite low-mass elliptical galaxies as a system, i.e., the satellite galaxies closer to the center of the host galaxy usually have redder color indices, for both their stars and their GCs. According to the "two phase" formation scenario of massive early-type galaxies, the host galaxy accretes stars and GCs from low-mass satellite galaxies in the second phase. So an accreted GC system naturally inherits the negative color gradient present in the satellite population. This can explain why the color gradient of the GC system can still be observed at large radii after multiple minor mergers.
  • Thumbnail Image
    Item
    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.
  • Thumbnail Image
    Item
    The Next Generation Virgo Cluster Survey (NGVS). XXIV. The Red Sequence to ~106 L⊙ and Comparisons with Galaxy Formation Models
    (2017) Roediger, Joel C.; Ferrarese, Laura; Côté, Patrick; MacArthur, Lauren A.; Sánchez Janssen, Rubén; Blakeslee, John P.; Peng, Eric W.; Liu, Chengze; Puzia, Thomas H.; Muñoz Soria, Roberto
  • Thumbnail Image
    Item
    The Next Generation Virgo Cluster Survey (NGVS). XXVI. The Issues of Photometric Age and Metallicity Estimates for Globular Clusters
    (2017) Powalka, Mathieu; Lançon, Ariane; Puzia, Thomas H.; Peng, Eric W.; Liu, Chengze; Muñoz, Roberto P.; Blakeslee, John P.; Côté, Patrick; Ferrarese, Laura; Zhang, Hongxin
  • Thumbnail Image
    Item
    The Next Generation Virgo Cluster Survey (NGVS). XXVII. The Size and Structure of Globular Cluster Systems and Their Connection to Dark Matter Halos
    (2024) Lim, Sungsoon; Peng, Eric W.; Cote, Patrick; Ferrarese, Laura; Roediger, Joel C.; Liu, Chengze; Spengler, Chelsea; Sola, Elisabeth; Duc, Pierre-Alain; Sales, Laura V.; Blakeslee, John P.; Cuillandre, Jean-Charles; Durrell, Patrick R.; Emsellem, Eric; Gwyn, Stephen D. J.; Lancon, Ariane; Marleau, Francine R.; Mihos, J. Christopher; Mueller, Oliver; Puzia, Thomas H.; Sanchez-Janssen, Ruben
    We study the size and structure of globular cluster (GC) systems of 118 early-type galaxies from the NGVS, MATLAS, and ACSVCS surveys. Fitting S & eacute;rsic profiles, we investigate the relationship between effective radii of GC systems (R-e,R-gc) and galaxy properties. GC systems are 2-4 times more extended than host galaxies across the entire stellar mass range of our sample (10(8.3)M(circle dot) < M-* < 10(11.6)M(circle dot)). The relationship between R-e,R-gc and galaxy stellar mass exhibits a characteristic "knee" at a stellar mass of M-p similar or equal to 10(10.8), similar to the galaxy R-e-stellar mass relationship. We present a new characterization of the traditional blue and red GC color subpopulations, describing them with respect to host galaxy color (Delta(gi)): GCs with similar colors to their hosts have a "red" Delta(gi), and those significantly bluer GCs have a "blue" Delta(gi). The GC populations with red Delta(gi), even in dwarf galaxies, are twice as extended as the stars, suggesting that formation or survival mechanisms favor the outer regions. We find a tight correlation between R-e,R-gc and the total number of GCs, with intrinsic scatter less than or similar to 0.1 dex spanning two and three orders of magnitude in size and number, respectively. This holds for both red and blue subpopulations, albeit with different slopes. Assuming that N-GC,N-Total correlates with M-200, we find that the red GC systems have effective radii of roughly 1%-5% R-200, while the blue GC systems in massive galaxies can have sizes as large as similar to 10% R-200. Environmental dependence on R-e,R-gc is also found, with lower-density environments exhibiting more extended GC systems at fixed mass.
  • Thumbnail Image
    Item
    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
  • Thumbnail Image
    Item
    The Next Generation Virgo Cluster Survey (NGVS). XXXII. A Search for Globular Cluster Substructures in the Virgo Galaxy Cluster Core
    (2018) Powalka, Mathieu; Puzia, Thomas H.; Lancon, Ariane; Longobardi, Alessia; Peng, Eric W.; Duc, Pierre-Alain; Alamo-Martinez, Karla; Blakeslee, John P.; Cote, Patrick; Cuillandre, Jean-Charles; Durrell, Patrick; Eigenthaler, Paul; Ferrarese, Laura; Guhathakurta, Puragra; Gwyn, S. D. J.; Hudelot, Patrick; Liu, Chengze; Mei, Simona; Munoz, Roberto P.; Roediger, Joel; Sanchez-Janssen, Ruben; Toloba, Elisa; Zhang, Hongxin
  • Thumbnail Image
    Item
    THE NEXT GENERATION VIRGO CLUSTER SURVEY. V. MODELING THE DYNAMICS OF M87 WITH THE MADE-TO-MEASURE METHOD
    (2014) Zhu, Ling; Long, R.J.; Mao, Shude; Peng, Eric W.; Liu, Chengze; Jordán Colzani, Andrés Cristóbal; Muñoz Soria, Roberto; Puzia, Thomas H.
  • No Thumbnail Available
    Item
    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.
  • No Thumbnail Available
    Item
    The Next Generation Virgo Cluster Survey. XXIII. Fundamentals of Nuclear Star Clusters over Seven Decades in Galaxy Mass
    (2019) Sanchez-Janssen, Ruben; Cote, Patrick; Ferrarese, Laura; Peng, Eric W.; Roediger, Joel; Blakeslee, John P.; Emsellem, Eric; Puzia, Thomas H.; Spengler, Chelsea; Taylor, James; Alamo-Martinez, Karla A.; Boselli, Alessandro; Cantiello, Michele; Cuillandre, Jean-Charles; Duc, Pierre-Alain; Durrell, Patrick; Gwyn, Stephen; MacArthur, Lauren A.; Lancon, Ariane; Lim, Sungsoon; Liu, Chengze; Mei, Simona; Miller, Bryan; Munoz, Roberto; Mihos, J. Christopher; Paudel, Sanjaya; Powalka, Mathieu; Toloba, Elisa
    Using deep, high-resolution optical imaging from the Next Generation Virgo Cluster Survey, we study the properties of nuclear star clusters (NSCs) in a sample of nearly 400 quiescent galaxies in the core of Virgo with stellar masses 10(5) less than or similar to M-*/M-circle dot less than or similar to 10(12). The nucleation fraction reaches a peak value f(n) approximate to 90% for M-* approximate to 10(9) M-circle dot galaxies and declines for both higher and lower masses, but nuclei populate galaxies as small as M-* approximate to 5 x 10(5) M-circle dot. Comparison with literature data for nearby groups and clusters shows that at the low-mass end nucleation is more frequent in denser environments. The NSC mass function peaks at M-NSC approximate to 7 x 10(5) M-circle dot, a factor 3-4 times larger than the turnover mass for globular clusters (GCs). We find a nonlinear relation between the stellar masses of NSCs and those of their host galaxies, with a mean nucleus-to-galaxy mass ratio that drops to M-NSC/M-* approximate to 3.6 x 10(-3) for M-* approximate to 5 x 10(9) M-circle dot galaxies. Nuclei in both more and less massive galaxies are much more prominent: M-NSC proportional to M-*(0.46) at the low-mass end, where nuclei are nearly 50% as massive as their hosts. We measure an intrinsic scatter in NSC masses at a fixed galaxy stellar mass of 0.4 dex, which we interpret as evidence that the process of NSC growth is significantly stochastic. At low galaxy masses we find a close connection between NSCs and GC systems, including very similar occupation distributions and comparable total masses. We discuss these results in the context of current dissipative and dissipationless models of NSC formation.
  • No Thumbnail Available
    Item
    The Next Generation Virgo Cluster Survey. XXXIII. Stellar Population Gradients in the Virgo Cluster Core Globular Cluster System
    (2022) Ko, Youkyung; Peng, Eric W.; Cote, Patrick; Ferrarese, Laura; Liu, Chengze; Longobardi, Alessia; Lancon, Ariane; Munoz, Roberto P.; Puzia, Thomas H.; Alamo-Martinez, Karla A.; Sales, Laura, V; Ramos-Almendares, Felipe; Abadi, Mario G.; Lee, Myung Gyoon; Hwang, Ho Seong; Caldwell, Nelson; Blakeslee, John P.; Boselli, Alessandro; Cuillandre, Jean-Charles; Duc, Pierre-Alain; Eyheramendy, Susana; Guhathakurta, Puragra; Gwyn, Stephen; Jordan, Andres; Lim, Sungsoon; Sanchez-Janssen, Ruben; Toloba, Elisa
    We present a study of the stellar populations of globular clusters (GCs) in the Virgo Cluster core with a homogeneous spectroscopic catalog of 692 GCs within a major-axis distance R (maj) = 840 kpc from M87. We investigate radial and azimuthal variations in the mean age, total metallicity, [Fe/H], and alpha-element abundance of blue (metal-poor) and red (metal-rich) GCs using their co-added spectra. We find that the blue GCs have a steep radial gradient in [Z/H] within R (maj) = 165 kpc, with roughly equal contributions from [Fe/H] and [alpha/Fe], and flat gradients beyond. By contrast, the red GCs show a much shallower gradient in [Z/H], which is entirely driven by [Fe/H]. We use GC-tagged Illustris simulations to demonstrate an accretion scenario where more massive satellites (with more metal- and alpha-rich GCs) sink further into the central galaxy than less massive ones, and where the gradient flattening occurs because of the low GC occupation fraction of low-mass dwarfs disrupted at larger distances. The dense environment around M87 may also cause the steep [alpha/Fe] gradient of the blue GCs, mirroring what is seen in the dwarf galaxy population. The progenitors of red GCs have a narrower mass range than those of blue GCs, which makes their gradients shallower. We also explore spatial inhomogeneity in GC abundances, finding that the red GCs to the northwest of M87 are slightly more metal-rich. Future observations of GC stellar population gradients will be useful diagnostics of halo merger histories.