PDF Hosted at the Radboud Repository of the Radboud University Nijmegen
Total Page:16
File Type:pdf, Size:1020Kb
Load more
Recommended publications
-
NGC 362: Another Globular Cluster with a Split Red Giant Branch⋆⋆⋆⋆⋆⋆
A&A 557, A138 (2013) Astronomy DOI: 10.1051/0004-6361/201321905 & c ESO 2013 Astrophysics NGC 362: another globular cluster with a split red giant branch,, E. Carretta1, A. Bragaglia1, R. G. Gratton2, S. Lucatello2, V. D’Orazi3,4, M. Bellazzini1, G. Catanzaro5, F. Leone6, Y. M om any 2,7, and A. Sollima1 1 INAF – Osservatorio Astronomico di Bologna, via Ranzani 1, 40127 Bologna, Italy e-mail: [email protected] 2 INAF – Osservatorio Astronomico di Padova, Vicolo dell’Osservatorio 5, 35122 Padova, Italy 3 Dept. of Physics and Astronomy, Macquarie University, Sydney, NSW, 2109 Australia 4 Monash Centre for Astrophysics, Monash University, School of Mathematical Sciences, Building 28, Clayton VIC 3800, Melbourne, Australia 5 INAF – Osservatorio Astrofisico di Catania, via S. Sofia 78, 95123 Catania, Italy 6 Dipartimento di Fisica e Astronomia, Università di Catania, via S. Sofia 78, 95123 Catania, Italy 7 European Southern Observatory, Alonso de Cordova 3107, Vitacura, Santiago, Chile Received 16 May 2013 / Accepted 11 July 2013 ABSTRACT We obtained FLAMES GIRAFFE+UVES spectra for both first- and second-generation red giant branch (RGB) stars in the globular cluster (GC) NGC 362 and used them to derive abundances of 21 atomic species for a sample of 92 stars. The surveyed elements include proton-capture (O, Na, Mg, Al, Si), α-capture (Ca, Ti), Fe-peak (Sc, V, Mn, Co, Ni, Cu), and neutron-capture elements (Y, Zr, Ba, La, Ce, Nd, Eu, Dy). The analysis is fully consistent with that presented for twenty GCs in previous papers of this series. Stars in NGC 362 seem to be clustered into two discrete groups along the Na-O anti-correlation with a gap at [O/Na] ∼ 0 dex. -
1990Aj 100. .445V the Astronomical Journal
.445V THE ASTRONOMICAL JOURNAL VOLUME 100, NUMBER 2 AUGUST 1990 100. MEASURING AGE DIFFERENCES AMONG GLOBULAR CLUSTERS HAVING SIMILAR METALLICITIES: A NEW METHOD AND FIRST RESULTS Don A. VandenBerg 1990AJ Department of Physics and Astronomy, University of Victoria, P.O. Box 1700, Victoria, British Columbia V8W 2Y2, Canada Michael BoLTEa) and Peter B. STETSONa),b) Dominion Astrophysical Observatory, National Research Council of Canada, 5071 West Saanich Road, Victoria, British Columbia V8X 4M6, Canada Received 2 April 1990; revised 4 May 1990 ABSTRACT A new method is described for comparing observed color-magnitude diagrams to obtain accurate relative ages for star clusters having similar chemical compositions. It is exceedingly simple and straightforward: the principal sequence for one system is superimposed on that for another by applying whatever vertical and horizontal shifts are needed to make their main-sequence turnoff segments coin- cide in both V magnitude and B — V color. When this has been done, any apparent separation of the two lower giant branch loci can be interpreted in terms of an age disparity since, as is well known from basic theory, the color difference between the turnoff and the giant branch is a monotonie and inverse function of age. This diagnostic has the distinct advantage that it is strictly independent of distance, reddening, and the zero-point of color calibrations; and theoretical isochrones show it to be nearly independent of metallicity—particularly for [m/H] < — 1.2. (In fact, if the cluster photometry is secure and the metal abundance is accurately known, our technique provides an excellent way to determine relative reddenings. -
Galactic Metal-Poor Halo E NCYCLOPEDIA of a STRONOMY and a STROPHYSICS
Galactic Metal-Poor Halo E NCYCLOPEDIA OF A STRONOMY AND A STROPHYSICS Galactic Metal-Poor Halo Most of the gas, stars and clusters in our Milky Way Galaxy are distributed in its rotating, metal-rich, gas-rich and flattened disk and in the more slowly rotating, metal- rich and gas-poor bulge. The Galaxy’s halo is roughly spheroidal in shape, and extends, with decreasing density, out to distances comparable with those of the Magellanic Clouds and the dwarf spheroidal galaxies that have been collected around the Galaxy. Aside from its roughly spheroidal distribution, the most salient general properties of the halo are its low metallicity relative to the bulk of the Galaxy’s stars, its lack of a gaseous counterpart, unlike the Galactic disk, and its great age. The kinematics of the stellar halo is closely coupled to the spheroidal distribution. Solar neighborhood disk stars move at a speed of about 220 km s−1 toward a point in the plane ◦ and 90 from the Galactic center. Stars belonging to the spheroidal halo do not share such ordered motion, and thus appear to have ‘high velocities’ relative to the Sun. Their orbital energies are often comparable with those of the disk stars but they are directed differently, often on orbits that have a smaller component of rotation or angular Figure 1. The distribution of [Fe/H] values for globular clusters. momentum. Following the original description by Baade in 1944, the disk stars are often called POPULATION I while still used to measure R . The recognizability of globular the metal-poor halo stars belong to POPULATION II. -
Using Gaia DR2 to Detect Extratidal Structures Around the Galactic Globular Cluster NGC 362
MNRAS 000,1{6 (2018) Preprint 5 April 2019 Compiled using MNRAS LATEX style file v3.0 Using Gaia DR2 to detect extratidal structures around the Galactic globular cluster NGC 362 Julio A. Carballo-Bello1;2? 1Instituto de Astrof´ısica, Facultad de F´ısica, Pontificia Universidad Cat´olica de Chile, Av. Vicu~na Mackenna 4860, 782-0436 Macul, Santiago, Chile 2Chinese Academy of Sciences South America Center for Astronomy, National Astronomical Observatories, CAS, Beijing 100101, China Accepted XXX. Received YYY; in original form ZZZ ABSTRACT We explore the possibility of searching for extratidal features around the Galactic globular cluster NGC 362 using the Gaia DR2 together with a modified version of a classical statistical decontamination algorithm. Our results suggest that an important stellar component is associated with this globular cluster, which is perfectly distin- guishable from the populations in the Small Magellanic Cloud and that of the nearby NGC 104 (47 Tucanae). We thus confirm once again the power of Gaia to disentangle different stellar components along the same line-of-sight. Key words: (Galaxy): globular clusters: individual: NGC 362 (Galaxy)- halo 1 INTRODUCTION binot et al. 2011; Sollima et al. 2011; Carballo-Bello et al. 2017; Navarrete et al. 2017). As for clusters in the densest The tidal stress exerted by the Milky Way on Galactic globu- areas of the Galaxy, i.e. disk and bulge, the identification of lar clusters (GCs) has a direct impact on their structure and the intrinsic color-magnitude diagram (CMD) features asso- evolution and varies in time as these systems move along ciated with the GC, specially in their low-density outer lay- their orbits. -
Caldwell Catalogue - Wikipedia, the Free Encyclopedia
Caldwell catalogue - Wikipedia, the free encyclopedia Log in / create account Article Discussion Read Edit View history Caldwell catalogue From Wikipedia, the free encyclopedia Main page Contents The Caldwell Catalogue is an astronomical catalog of 109 bright star clusters, nebulae, and galaxies for observation by amateur astronomers. The list was compiled Featured content by Sir Patrick Caldwell-Moore, better known as Patrick Moore, as a complement to the Messier Catalogue. Current events The Messier Catalogue is used frequently by amateur astronomers as a list of interesting deep-sky objects for observations, but Moore noted that the list did not include Random article many of the sky's brightest deep-sky objects, including the Hyades, the Double Cluster (NGC 869 and NGC 884), and NGC 253. Moreover, Moore observed that the Donate to Wikipedia Messier Catalogue, which was compiled based on observations in the Northern Hemisphere, excluded bright deep-sky objects visible in the Southern Hemisphere such [1][2] Interaction as Omega Centauri, Centaurus A, the Jewel Box, and 47 Tucanae. He quickly compiled a list of 109 objects (to match the number of objects in the Messier [3] Help Catalogue) and published it in Sky & Telescope in December 1995. About Wikipedia Since its publication, the catalogue has grown in popularity and usage within the amateur astronomical community. Small compilation errors in the original 1995 version Community portal of the list have since been corrected. Unusually, Moore used one of his surnames to name the list, and the catalogue adopts "C" numbers to rename objects with more Recent changes common designations.[4] Contact Wikipedia As stated above, the list was compiled from objects already identified by professional astronomers and commonly observed by amateur astronomers. -
Pos(NIC XI)201
PoS(NIC XI)201 Neutron-capture element abundances in the globular clusters: 47 Tuc, NGC 6388, NGC 362 & w Cen C. C. Worley∗ Université de Nice Sophia Antipolis, CNRS (UMR 6202), Observatoire de la Côte d’Azur, Cassiopée, B.P.4229, 06304 Nice Cedex 04, France University of Canterbury, Private Bag 4800, Christchurch 8140, New Zealand E-mail: [email protected] P. L. Cottrell University of Canterbury, Private Bag 4800, Christchurch 8140, New Zealand E-mail: [email protected] J. D. Simpson University of Canterbury, Private Bag 4800, Christchurch 8140, New Zealand E-mail: [email protected] c Copyright owned by the author(s) under the terms of the Creative Commons Attribution-NonCommercial-ShareAlike Licence. http://pos.sissa.it/ A spectroscopic study of neutron-capture element abundances has been carried out in the globular clusters, 47 Tuc, NGC 6388, NGC 362 and w Cen, using high- and medium- resolution data. The stars analysed at high resolution, using data acquired with Ultraviolet Echelle Spectrograph (UVES) on the Very Large Telescope (VLT), were luminous giant stars located near the asymp- totic giant branch for 47 Tuc, NGC 6388 and NGC 362. The medium resolution studies have analysed stars that reached below the level of the horizontal branch in at least one cluster, 47 Tuc. We are also exploring the possibility of undertaking large-scale studies using the Fabry–Pérot In- terferometer (FPI) on the Robert Stobie Spectrograph on the Southern African Large Telescope. With the high resolution UVES data, two stars were analysed in NGC 6388, five stars in 47 Tuc and eleven stars in NGC 362. -
A Dynamical Study of Galactic Globular Clusters Under Different Relaxation Conditions
Edinburgh Research Explorer A dynamical study of Galactic globular clusters under different relaxation conditions Citation for published version: Zocchi, A, Bertin, G & Varri, AL 2012, 'A dynamical study of Galactic globular clusters under different relaxation conditions', Astronomy & Astrophysics, vol. 539. https://doi.org/10.1051/0004-6361/201117977 Digital Object Identifier (DOI): 10.1051/0004-6361/201117977 Link: Link to publication record in Edinburgh Research Explorer Document Version: Publisher's PDF, also known as Version of record Published In: Astronomy & Astrophysics General rights Copyright for the publications made accessible via the Edinburgh Research Explorer is retained by the author(s) and / or other copyright owners and it is a condition of accessing these publications that users recognise and abide by the legal requirements associated with these rights. Take down policy The University of Edinburgh has made every reasonable effort to ensure that Edinburgh Research Explorer content complies with UK legislation. If you believe that the public display of this file breaches copyright please contact [email protected] providing details, and we will remove access to the work immediately and investigate your claim. Download date: 29. Sep. 2021 A&A 539, A65 (2012) Astronomy DOI: 10.1051/0004-6361/201117977 & c ESO 2012 Astrophysics A dynamical study of Galactic globular clusters under different relaxation conditions A. Zocchi, G. Bertin, and A. L. Varri Università degli Studi di Milano, Dipartimento di Fisica, via Celoria 16, 20133 Milano, Italy e-mail: [email protected] Received 30 August 2011 / Accepted 22 December 2011 ABSTRACT Aims. We perform a systematic combined photometric and kinematic analysis of a sample of globular clusters under different relax- ation conditions, based on their core relaxation time (as listed in available catalogs), by means of two well-known families of spherical stellar dynamical models. -