Deep Radio Imaging of Globular Clusters and the Cluster Pulsar Population
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First Scientific Results with the VLT in Visitor and Service Modes
No. 98 – December 1999 First Scientific Results with the VLT in Visitor and Service Modes Starting with this issue, The Messenger will regularly include scientific results obtained with the VLT. One of the results reported in this issue is a study of NGC 3603, the most massive visible H II region in the Galaxy, with VLT/ISAAC in the near-infrared Js, H, and Ks-bands and HST/WFPC2 at Hα and [N II] wavelengths. These VLT observations are the most sensitive near-infrared observations made to date of a dense starburst region, allowing one to in- vestigate with unprecedented quality its low-mass stellar population. The sensitivity limit to stars detected in all three bands corresponds to 0.1 M0 for a pre-main-sequence star of age 0.7 Myr. The observations clearly show that sub-solar-mass stars down to at least 0.1 M0 do form in massive starbursts (from B. Brandl, W. Brandner, E.K. Grebel and H. Zinnecker, page 46). Js versus Js–Ks colour-magnitude diagrams of NGC 3603. The left-hand panel contains all stars detected in all three wave- bands in the entire field of view (3.4′×3.4′, or 6 pc × 6 pc); the centre panel shows the field stars at r > 75″ (2.25 pc) around the cluster, and the right-hand panel shows the cluster population within r < 33″ (1pc) with the field stars statistically subtracted. The dashed horizontal line (left-hand panel) indicates the detection limit of the previous most sensitive NIR study (Eisenhauer et al. -
Spatial Distribution of Galactic Globular Clusters: Distance Uncertainties and Dynamical Effects
Juliana Crestani Ribeiro de Souza Spatial Distribution of Galactic Globular Clusters: Distance Uncertainties and Dynamical Effects Porto Alegre 2017 Juliana Crestani Ribeiro de Souza Spatial Distribution of Galactic Globular Clusters: Distance Uncertainties and Dynamical Effects Dissertação elaborada sob orientação do Prof. Dr. Eduardo Luis Damiani Bica, co- orientação do Prof. Dr. Charles José Bon- ato e apresentada ao Instituto de Física da Universidade Federal do Rio Grande do Sul em preenchimento do requisito par- cial para obtenção do título de Mestre em Física. Porto Alegre 2017 Acknowledgements To my parents, who supported me and made this possible, in a time and place where being in a university was just a distant dream. To my dearest friends Elisabeth, Robert, Augusto, and Natália - who so many times helped me go from "I give up" to "I’ll try once more". To my cats Kira, Fen, and Demi - who lazily join me in bed at the end of the day, and make everything worthwhile. "But, first of all, it will be necessary to explain what is our idea of a cluster of stars, and by what means we have obtained it. For an instance, I shall take the phenomenon which presents itself in many clusters: It is that of a number of lucid spots, of equal lustre, scattered over a circular space, in such a manner as to appear gradually more compressed towards the middle; and which compression, in the clusters to which I allude, is generally carried so far, as, by imperceptible degrees, to end in a luminous center, of a resolvable blaze of light." William Herschel, 1789 Abstract We provide a sample of 170 Galactic Globular Clusters (GCs) and analyse its spatial distribution properties. -
Astronomy Magazine Special Issue
γ ι ζ γ δ α κ β κ ε γ β ρ ε ζ υ α φ ψ ω χ α π χ φ γ ω ο ι δ κ α ξ υ λ τ μ β α σ θ ε β σ δ γ ψ λ ω σ η ν θ Aι must-have for all stargazers η δ μ NEW EDITION! ζ λ β ε η κ NGC 6664 NGC 6539 ε τ μ NGC 6712 α υ δ ζ M26 ν NGC 6649 ψ Struve 2325 ζ ξ ATLAS χ α NGC 6604 ξ ο ν ν SCUTUM M16 of the γ SERP β NGC 6605 γ V450 ξ η υ η NGC 6645 M17 φ θ M18 ζ ρ ρ1 π Barnard 92 ο χ σ M25 M24 STARS M23 ν β κ All-in-one introduction ALL NEW MAPS WITH: to the night sky 42,000 more stars (87,000 plotted down to magnitude 8.5) AND 150+ more deep-sky objects (more than 1,200 total) The Eagle Nebula (M16) combines a dark nebula and a star cluster. In 100+ this intense region of star formation, “pillars” form at the boundaries spectacular between hot and cold gas. You’ll find this object on Map 14, a celestial portion of which lies above. photos PLUS: How to observe star clusters, nebulae, and galaxies AS2-CV0610.indd 1 6/10/10 4:17 PM NEW EDITION! AtlAs Tour the night sky of the The staff of Astronomy magazine decided to This atlas presents produce its first star atlas in 2006. -
A Basic Requirement for Studying the Heavens Is Determining Where In
Abasic requirement for studying the heavens is determining where in the sky things are. To specify sky positions, astronomers have developed several coordinate systems. Each uses a coordinate grid projected on to the celestial sphere, in analogy to the geographic coordinate system used on the surface of the Earth. The coordinate systems differ only in their choice of the fundamental plane, which divides the sky into two equal hemispheres along a great circle (the fundamental plane of the geographic system is the Earth's equator) . Each coordinate system is named for its choice of fundamental plane. The equatorial coordinate system is probably the most widely used celestial coordinate system. It is also the one most closely related to the geographic coordinate system, because they use the same fun damental plane and the same poles. The projection of the Earth's equator onto the celestial sphere is called the celestial equator. Similarly, projecting the geographic poles on to the celest ial sphere defines the north and south celestial poles. However, there is an important difference between the equatorial and geographic coordinate systems: the geographic system is fixed to the Earth; it rotates as the Earth does . The equatorial system is fixed to the stars, so it appears to rotate across the sky with the stars, but of course it's really the Earth rotating under the fixed sky. The latitudinal (latitude-like) angle of the equatorial system is called declination (Dec for short) . It measures the angle of an object above or below the celestial equator. The longitud inal angle is called the right ascension (RA for short). -
Globular Clusters in the Inner Galaxy Classified from Dynamical Orbital
MNRAS 000,1{17 (2019) Preprint 14 November 2019 Compiled using MNRAS LATEX style file v3.0 Globular clusters in the inner Galaxy classified from dynamical orbital criteria Angeles P´erez-Villegas,1? Beatriz Barbuy,1 Leandro Kerber,2 Sergio Ortolani3 Stefano O. Souza 1 and Eduardo Bica,4 1Universidade de S~aoPaulo, IAG, Rua do Mat~ao 1226, Cidade Universit´aria, S~ao Paulo 05508-900, Brazil 2Universidade Estadual de Santa Cruz, Rodovia Jorge Amado km 16, Ilh´eus 45662-000, Brazil 3Dipartimento di Fisica e Astronomia `Galileo Galilei', Universit`adi Padova, Vicolo dell'Osservatorio 3, Padova, I-35122, Italy 4Universidade Federal do Rio Grande do Sul, Departamento de Astronomia, CP 15051, Porto Alegre 91501-970, Brazil Accepted XXX. Received YYY; in original form ZZZ ABSTRACT Globular clusters (GCs) are the most ancient stellar systems in the Milky Way. There- fore, they play a key role in the understanding of the early chemical and dynamical evolution of our Galaxy. Around 40% of them are placed within ∼ 4 kpc from the Galactic center. In that region, all Galactic components overlap, making their disen- tanglement a challenging task. With Gaia DR2, we have accurate absolute proper mo- tions for the entire sample of known GCs that have been associated with the bulge/bar region. Combining them with distances, from RR Lyrae when available, as well as ra- dial velocities from spectroscopy, we can perform an orbital analysis of the sample, employing a steady Galactic potential with a bar. We applied a clustering algorithm to the orbital parameters apogalactic distance and the maximum vertical excursion from the plane, in order to identify the clusters that have high probability to belong to the bulge/bar, thick disk, inner halo, or outer halo component. -
Global Fitting of Globular Cluster Age Indicators
A&A 456, 1085–1096 (2006) Astronomy DOI: 10.1051/0004-6361:20065133 & c ESO 2006 Astrophysics Global fitting of globular cluster age indicators F. Meissner1 and A. Weiss1 Max-Planck-Institut für Astrophysik, Karl-Schwarzschild-Str. 1, 85748 Garching, Germany e-mail: [meissner;weiss]@mpa-garching.mpg.de Received 3 March 2006 / Accepted 12 June 2006 ABSTRACT Context. Stellar models and the methods for the age determinations of globular clusters are still in need of improvement. Aims. We attempt to obtain a more objective method of age determination based on cluster diagrams, avoiding the introduction of biases due to the preference of one single age indicator. Methods. We compute new stellar evolutionary tracks and derive the dependence of age indicating points along the tracks and isochrone – such as the turn-off or bump location – as a function of age and metallicity. The same critical points are identified in the colour-magnitude diagrams of globular clusters from a homogeneous database. Several age indicators are then fitted simultaneously, and the overall best-fitting isochrone is selected to determine the cluster age. We also determine the goodness-of-fit for different sets of indicators to estimate the confidence level of our results. Results. We find that our isochrones provide no acceptable fit for all age indicators. In particular, the location of the bump and the brightness of the tip of the red giant branch are problematic. On the other hand, the turn-off region is very well reproduced, and restricting the method to indicators depending on it results in trustworthy ages. Using an alternative set of isochrones improves the situation, but neither leads to an acceptable global fit. -
Skytools Chart
29 Scorpius - Ophiuchus SkyTools 3 / Skyhound.com M107 ο ν Box Nebula γ Libra η ξ Eagle Nebula φ θ α2 6356 χ M9 Omega Nebula PK 008+06.1 ν 2 β β1 6342 ψ κ M 23 1 ω 1 6567 2 ι 6440 ω ω Red Spider ξ IC 4634 NGC 6595 6235 5897 6287 M80 δ NGC 6568 μ NGC 6469 6325 ρ M 21 ο Little Ghost Nebula PK 342+27.1 M 20 6401 NGC 6546 6284 Collinder 367 Trifid Nebula θ 6144 M4 σ NGC 6530 M19 Antares π Lagoon Nebula 6293 6544 6355 Collinder 302 σ M28 6553 τ 6316 υ PK 001-00.1 ρ 5694 6540 NGC 6520 PK 357+02.1 6304 Collinder 351 M62 PK 003-04.7 τ PK 002-03.5 Collinder 331 6528 γ1 Tom Thumb Cluster 26522 NGC 6416 δ γ NGC 6425 PK 002-05.1 Collinder 337 6624 NGC 6383 -3 PK 001-06.2 0° Butterfly Cluster χ 6558 Collinder 336 ε 1 5824 6569 PK 356-03.4 2ψ PK 357-04.3 ψ M69 Scorpius PK 358-06.1 M 7 6453 6652 θ ε Collinder 355 NGC 6400 2 λ υ NGC 6281 μ1 5986 φ 6441 PK 353-04.1 Collinder 332 μ2 6139 η PK 355-06.1 η Collinder 338 NGC 6268 NGC 6242 5873 6153 κ Collinder 318 NGC 6124 PK 352-07.1 Collinder 316 Collinder 343 ι1 NGC 6231 γ δ ψ ζ 2 1 NGC 6322 ζ NGC 6192 ω η θ μ κ -40 PK 345-04.1 NGC 6249 Mu Normae Cluster Lupus ° β η 6388 NGC 6259 NGC 6178 δ 6541 6496 NGC 6250 ε ο θ PK 342-04.1 1 52° x 34° 8 5882 h λ 16h30m00.0s -30°00'00" (Skymark) Globular Cl. -
Properties of Stellar Generations in Globular Clusters and Relations With
Astronomy & Astrophysics manuscript no. carretta c ESO 2018 November 9, 2018 Properties of stellar generations in Globular Clusters and relations with global parameters ⋆ E. Carretta1, A. Bragaglia1, R.G. Gratton2, A. Recio-Blanco3, S. Lucatello2,4, V. D’Orazi2, and S. Cassisi5 1 INAF-Osservatorio Astronomico di Bologna, via Ranzani 1, I-40127 Bologna, Italy 2 INAF-Osservatorio Astronomico di Padova, vicolo dell’Osservatorio 5, I-35122 Padova, Italy 3 Laboratoire Cassiop´ee UMR 6202, Universit`ede Nice Sophia-Antipolis, CNRS, Observatoire de la Cote d’Azur, BP 4229, 06304 Nice Cedex 4, France 4 Excellence Cluster Universe, Technische Universit¨at M¨unchen, Boltzmannstr. 2, D-85748, Garching, Germany 5 INAF-Osservatorio Astronomico di Collurania, via M. Maggini, I-64100 Teramo, Italy Received .....; accepted ..... ABSTRACT We revise the scenario of the formation of Galactic globular clusters (GCs) by adding the observed detailed chemical composition of their different stellar generations to the set of their global parameters. We exploit the unprecedented set of homogeneous abundances of more than 1200 red giants in 19 clusters, as well as additional data from literature, to give a new definition of bona fide globular clusters, as the stellar aggregates showing the presence of the Na-O anticorrelation. We propose a classification of GCs according to their kinematics and location in the Galaxy in three populations: disk/bulge, inner halo, and outer halo. We find that the luminosity function of globular clusters is fairly independent of their population, suggesting that it is imprinted by the formation mechanism, and only marginally affected by the ensuing evolution. We show that a large fraction of the primordial population should have been lost by the proto-GCs. -
Astronomical Coordinate Systems
Appendix 1 Astronomical Coordinate Systems A basic requirement for studying the heavens is being able to determine where in the sky things are located. To specify sky positions, astronomers have developed several coordinate systems. Each sys- tem uses a coordinate grid projected on the celestial sphere, which is similar to the geographic coor- dinate system used on the surface of the Earth. The coordinate systems differ only in their choice of the fundamental plane, which divides the sky into two equal hemispheres along a great circle (the fundamental plane of the geographic system is the Earth’s equator). Each coordinate system is named for its choice of fundamental plane. The Equatorial Coordinate System The equatorial coordinate system is probably the most widely used celestial coordinate system. It is also the most closely related to the geographic coordinate system because they use the same funda- mental plane and poles. The projection of the Earth’s equator onto the celestial sphere is called the celestial equator. Similarly, projecting the geographic poles onto the celestial sphere defines the north and south celestial poles. However, there is an important difference between the equatorial and geographic coordinate sys- tems: the geographic system is fixed to the Earth and rotates as the Earth does. The Equatorial system is fixed to the stars, so it appears to rotate across the sky with the stars, but it’s really the Earth rotating under the fixed sky. The latitudinal (latitude-like) angle of the equatorial system is called declination (Dec. for short). It measures the angle of an object above or below the celestial equator. -
Globular Cluster Club
Globular Cluster Observing Club Raleigh Astronomy Club Version 1.2 22 June 2007 Introduction Welcome to the Globular Cluster Observing Club! This list is intended to give you an appreciation for the deep-sky objects known as globular clusters. There are 153 known Milky Way Globular Clusters of which the entire list can be found on the seds.org site listed below. To receive your Gold level we will only have you do sixty of them along with one challenge object from a list of three. Challenge objects being the extra-galactic globular Mayall II (G1) located in the Andromeda Galaxy, Palomar 4 in Ursa Major, and Omega Centauri a magnificent southern globular. The first two challenge your scope and viewing ability while Omega Centauri challenges your ability to plan for a southern view. A Silver level is also available and will be within the range of a 4 inch to 8 inch scope depending upon seeing conditions. Many of the objects are found in the Messier, Caldwell, or Herschel catalogs and can springboard you into those clubs. The list is meant for your viewing enrichment and edification of these types of clusters. It is also meant to enhance your viewing skills. You are encouraged to view the clusters with a critical eye toward the cluster’s size, visual magnitude, resolvability, concentration and colors. The Astronomical League’s Globular Clusters Club book “Guide to the Globular Cluster Observing Club” is an excellent resource for this endeavor. You will be asked to either sketch the cluster or give a short description of your visual impression, citing seeing conditions, time, date, cluster’s size, magnitude, resolvability, concentration, and any star colors. -
Binocular Challenges
This page intentionally left blank Cosmic Challenge Listing more than 500 sky targets, both near and far, in 187 challenges, this observing guide will test novice astronomers and advanced veterans alike. Its unique mix of Solar System and deep-sky targets will have observers hunting for the Apollo lunar landing sites, searching for satellites orbiting the outermost planets, and exploring hundreds of star clusters, nebulae, distant galaxies, and quasars. Each target object is accompanied by a rating indicating how difficult the object is to find, an in-depth visual description, an illustration showing how the object realistically looks, and a detailed finder chart to help you find each challenge quickly and effectively. The guide introduces objects often overlooked in other observing guides and features targets visible in a variety of conditions, from the inner city to the dark countryside. Challenges are provided for viewing by the naked eye, through binoculars, to the largest backyard telescopes. Philip S. Harrington is the author of eight previous books for the amateur astronomer, including Touring the Universe through Binoculars, Star Ware, and Star Watch. He is also a contributing editor for Astronomy magazine, where he has authored the magazine’s monthly “Binocular Universe” column and “Phil Harrington’s Challenge Objects,” a quarterly online column on Astronomy.com. He is an Adjunct Professor at Dowling College and Suffolk County Community College, New York, where he teaches courses in stellar and planetary astronomy. Cosmic Challenge The Ultimate Observing List for Amateurs PHILIP S. HARRINGTON CAMBRIDGE UNIVERSITY PRESS Cambridge, New York, Melbourne, Madrid, Cape Town, Singapore, Sao˜ Paulo, Delhi, Dubai, Tokyo, Mexico City Cambridge University Press The Edinburgh Building, Cambridge CB2 8RU, UK Published in the United States of America by Cambridge University Press, New York www.cambridge.org Information on this title: www.cambridge.org/9780521899369 C P. -
Making a Sky Atlas
Appendix A Making a Sky Atlas Although a number of very advanced sky atlases are now available in print, none is likely to be ideal for any given task. Published atlases will probably have too few or too many guide stars, too few or too many deep-sky objects plotted in them, wrong- size charts, etc. I found that with MegaStar I could design and make, specifically for my survey, a “just right” personalized atlas. My atlas consists of 108 charts, each about twenty square degrees in size, with guide stars down to magnitude 8.9. I used only the northernmost 78 charts, since I observed the sky only down to –35°. On the charts I plotted only the objects I wanted to observe. In addition I made enlargements of small, overcrowded areas (“quad charts”) as well as separate large-scale charts for the Virgo Galaxy Cluster, the latter with guide stars down to magnitude 11.4. I put the charts in plastic sheet protectors in a three-ring binder, taking them out and plac- ing them on my telescope mount’s clipboard as needed. To find an object I would use the 35 mm finder (except in the Virgo Cluster, where I used the 60 mm as the finder) to point the ensemble of telescopes at the indicated spot among the guide stars. If the object was not seen in the 35 mm, as it usually was not, I would then look in the larger telescopes. If the object was not immediately visible even in the primary telescope – a not uncommon occur- rence due to inexact initial pointing – I would then scan around for it.