We utilise the DEIMOS instrument on the Keck telescope to measure the wide-field stellar kinematics of early-type galaxies as part of the SAGES Legacy Unifying Globulars and GalaxieS (SLUGGS) survey. In this paper, we focus on some of the lowest stellar mass lenticular galaxies within this survey, namely NGC 2549, NGC 4474, NGC 4459 and NGC 7457, performing detailed kinematic analyses out to large radial distances of $\sim 2-3$ effective radii. For NGC 2549, we present the first analysis of data taken with the SuperSKiMS (Stellar Kinematics from Multiple Slits) technique.
To better probe kinematic variations in the outskirts of the SLUGGS galaxies, we have defined a local measure of stellar spin. We use this parameter and identify a clear separation in the radial behaviour of stellar spin between lenticular and elliptical galaxies, thereby reinforcing the physically meaningful nature of their morphological classifications.
We compare the kinematic properties of our galaxies with those from various simulated galaxies to extract plausible formation scenarios. By doing this for multiple simulations, we assess the consistency of the theoretical results. Comparisons to binary merger simulations show that low-mass lenticular galaxies generally resemble the spiral progenitors more than the merger remnants themselves, an indication that these galaxies are not formed through merger events. We find, however, that recent mergers cannot be ruled out for some lenticular galaxies.
Early-type (E and S0) galaxies may have assembled via a variety of different evolutionary pathways. Here we investigate these pathways by comparing the stellar kinematic properties of 24 early-type galaxies from the SLUGGS survey with the hydrodynamical simulations of Naab et al. (2014). In particular, we use the kinematics of starlight up to 4 effective radii (R$_e$) as diagnostics of galaxy inner and outer regions, and assign each galaxy to one of six Naab et al. assembly classes. The majority of our galaxies (14/24) have kinematic characteristics that indicate an assembly history dominated …
Globular cluster ages provide both an important test of models of globular cluster formation and a powerful method to constrain the assembly history of galaxies. Unfortunately, measuring the ages of unresolved old stellar populations has proven challenging. Here, we present a novel technique that combines optical photometry with metallicity constraints from near-infrared spectroscopy in order to measure ages. After testing the method on globular clusters in the Milky Way and its satellite galaxies, we apply our technique to three massive early-type galaxies using data from the SLUGGS Survey. T…
We investigate the kinematic properties of nine nearby early-type galaxies with evidence of a disk-like component. Three of these galaxies are located in the field, five in the group and only one in the cluster environment. By combining the kinematics of the stars with those of the globular clusters (GCs) and planetary nebulae (PNe), we probe the outer regions of our galaxies out to $\sim$4-6 Re. Six galaxies have PNe and red GCs that show good kinematic alignment with the stars, whose rotation occurs along the photometric major-axis of the galaxies, suggesting that both the PNe and red GCs ar…
We use globular cluster kinematics data, primarily from the SLUGGS survey, to measure the dark matter fraction ($f_{\rm DM}$) and the average dark matter density ($\left< ρ_{\rm DM} \right>$) within the inner 5 effective radii ($R_{\rm e}$) for 32 nearby early--type galaxies (ETGs) with stellar mass log $(M_*/\rm M_\odot)$ ranging from $10.1$ to $11.8$. We compare our results with a simple galaxy model based on scaling relations as well as with cosmological hydrodynamical simulations where the dark matter profile has been modified through various physical processes. We find a high $f_{\rm DM}$…
Due to its proximity (9 Mpc) and the strongly bimodal color distribution of its spectroscopically well-sampled globular cluster (GC) system, the early-type galaxy NGC 3115 provides one of the best available tests of whether the color bimodality widely observed in GC systems generally reflects a true metallicity bimodality. Color bimodality has alternatively been attributed to a strongly nonlinear color--metallicity relation reflecting the influence of hot horizontal branch stars. Here we couple Subaru Suprime-Cam gi photometry with Keck/DEIMOS spectroscopy to accurately measure GC colors and a…
We use the kinematics of discrete tracers, primarily globular clusters (GCs) and planetary nebulae (PNe), along with measurements of the integrated starlight to explore the assembly histories of early type galaxies. Data for GCs and stars are taken from the SLUGGS wide field, 2-dimensional, chemo-dynamical survey (Brodie et al. 2014). Data for PNe are from the PN.S survey (see contributions by Gerhard and by Arnaboldi, this volume). We find widespread evidence for 2-phase galaxy assembly and intriguing constraints on hierarchical merging under a lambda CDM cosmology.
We study the present-day rotational velocity ($V_{rot}$) and velocity dispersion ($σ$) profiles of the globular cluster (GC) systems in a sample of 50 lenticular (S0) galaxies from the E-MOSAICS galaxy formation simulations. We find that 82% of the galaxies have GCs that are rotating along the photometric major axis of the galaxy ($aligned$), while the remaining 18% of the galaxies do not ($misaligned$). This is generally consistent with the observations from the SLUGGS survey. For the $aligned$ galaxies, classified as $peaked$ $and$ $outwardly$ $decreasing$ (49%), $flat$ (24%) and $increasing…
Different processes have been proposed to explain the formation of S0s, including mergers, disc instabilities and quenched spirals. These processes are expected to dominate in different environments, and thus leave characteristic footprints in the kinematics and stellar populations of the individual components within the galaxies. New techniques enable us to cleanly disentangle the kinematics and stellar populations of these components in IFU observations. In this paper, we use buddi to spectroscopically extract the light from the bulge, disc and lens components within a sample of 8 S0 galaxie…
Untangling Similarities and Differences in Star Formation Histories Across Cosmological Simulations
Canadian Institute for Theoretical Astrophysics, University of Toronto（多伦多大学理论天体物理研究所）；David A. Dunlap Department of Astronomy & Astrophysics, University of Toronto（多伦多大学大卫·邓普克天文与天体物理系）；Department of Statistical Sciences, University of Toronto（多伦多大学统计科学系）；Dunlap Institute for Astronomy & Astrophysics, University of Toronto（多伦多大学邓普克天文与天体物理研究所）；Data Sciences Institute, University of Toronto（多伦多大学数据科学研究所）；Institute for Astronomy, University of Hawaiʻi（夏威夷大学天体物理研究所）
We report on observational evidence of an extra-tidal clumpy structure around NGC 288 from an homogeneous coverage of a large area with the Pan-STARRS PS1 database. The extra-tidal star population has been disentangled from that of the Milky Way field by using a cleaning technique that successfully reproduced the stellar density, luminosity function and colour distributions of MW field stars. We have produced the cluster stellar density radial profile and a stellar density map from independent approaches, from which we found results in excellent agreement : the feature extends up to 3.5 times …
The observed properties of galaxies are strongly dependent on both their total stellar mass and their morphology. Furthermore, the environment is known to play a strong role in shaping them. The galaxy population in the local universe that is located in virialized clusters is found to be red, poorly star-forming, and mostly composed of early morphological types. Towards a holistic understanding of the mechanisms that drive galaxy evolution, we exploit the spectrophotometric data from the WINGS and OmegaWINGS local galaxy cluster surveys, and study the role of both the local and the large-scale…
We here present the first spatially-resolved study of the IMF in external galaxies derived using a dynamical tracer of the mass-to-light ratio. We use the kinematics of relaxed molecular gas discs in seven early-type galaxies (ETGs) selected from the ATLAS3D survey to dynamically determine mass-to-light ratio (M/L) gradients. These M/L gradients are not very strong in the inner parts of these objects, and galaxies that do show variations are those with the highest specific star formation rates. Stellar population parameters derived from star formation histories are then used in order to estima…
The MAGPI survey: Stellar population radial trends and mass assembly in star-forming galaxies at z~0.3
University of Vienna（维也纳大学）；Universidade do Porto（波尔图大学）；Instituto de Astrofísica e Ciências do Espaço, Universidade do Porto（波尔图大学空间与天体物理研究所）；University of Strasbourg（斯特拉斯堡大学）；SISSA- International School for Advanced Studies（国际高等研究院）；UWC- University of the Western Cape（西开普大学）；IFPU- Institute for Fundamental Physics of the Universe（宇宙基础物理研究所）；INFN-Sezione di Trieste（意大利国家核物理研究所的里雅斯特分部）；Durham University（杜伦大学）
Glance: A Comprehensive Framework for Galactic Archaeology
University of Vienna（维也纳大学）；Institut de Radioastronomie Millimétrique (IRAM)（毫米波射电天文学研究所）；Instituto de Astrofísica de Canarias（加那利群岛天体物理研究所）；Universidad de La Laguna（拉古纳大学）；Graduate Institute for Advanced Studies, SOKENDAI（日本综合研究大学院大学）；Subaru Telescope, National Astronomical Observatory of Japan（国立天文台昴星望远镜）
The GECKOS Survey: revealing the formation history of a barred galaxy via structural decomposition and resolved spectroscopy
European Southern Observatory（欧洲南方天文台）；Durham University（杜伦大学）；Liverpool John Moores University（利物浦约翰摩尔斯大学）；University of Oxford（牛津大学）；Cardiff University（卡迪夫大学）；Swinburne University of Technology（斯威本科技大学）；University of Oklahoma（俄克拉荷马大学）
We perform a direct comparison of two state-of-the art single stellar population (SSP) models that have been used to demonstrate the non-universality of the low-mass end of the Initial Mass Function (IMF) slope. The two public versions of the SSP models are restricted to either solar abundance patterns or solar metallicity, too restrictive if one aims to disentangle elemental enhancements, metallicity changes and IMF variations in massive early-type galaxies (ETGs) with star formation histories different from the solar neighborhood. We define response functions (to metallicity and α-abundance)…
The stellar kinematics of the spheroids and discs of S0 galaxies contain clues to their formation histories. Unfortunately, it is difficult to disentangle the two components and to recover their stellar kinematics in the faint outer parts of the galaxies using conventional absorption line spectroscopy. This paper therefore presents the stellar kinematics of six S0 galaxies derived from observations of planetary nebulae (PNe), obtained using the Planetary Nebula Spectrograph. To separate the kinematics of the two components, we use a maximum-likelihood method that combines the discrete kinemati…
Heavy black hole seed survivors in dwarf galaxies: a case study of Leo I
Columbia University（哥伦比亚大学）；Harvard University（哈佛大学）；Harvard & Smithsonian（哈佛-史密森尼天体物理中心）；Institute of Science and Technology Austria (ISTA)（奥地利科学与技术研究所）
本文通过蒙特卡洛并合树模拟类银河系晕及其卫星，研究矮星系狮子座 I 是否可能拥有重种子黑洞后代，发现重种子幸存者比例随激活温度降低而显著升高，表明狮子座 I 或可成为区分超大质量黑洞形成机制的关键案例。
LEGGOS I: The JWST LEGGOS Survey -- LEnsing and Galaxy Growth: Observing Substructures -- Unpacks the Nature of Clumpy Star Formation and Quenching in Gravitationally Lensed Galaxies beyond Cosmic Noon
University of Washington（华盛顿大学）；University of Pittsburgh（匹兹堡大学）；University of Arizona（亚利桑那大学）；Eureka Scientific（尤里卡科学公司）；University of Cincinnati（辛辛那提大学）；NASA Goddard Space Flight Center（美国国家航空航天局戈达德太空飞行中心）
