Ω Cen 127 M96 = NGC 3377 116 582
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Clusters of Galaxies…
Budapest University, MTA-Eötvös François Mernier …and the surprisesoftheir spectacularhotatmospheres Clusters ofgalaxies… K complex ) ⇤ Fe ) α [email protected] - Wallon Super - Wallon [email protected] Fe XXVI (Ly (/ Fe XXIV) L complex ) ) (incl. Ne) α α ) Fe ) ) α ) α α ) ) ) ) α ⇥ ) ) ) α α α α α α Si XIV (Ly Mg XII (Ly Ni XXVII / XXVIII Fe XXV (He S XVI (Ly O VIII (Ly Si XIII (He S XV (He Ca XIX (He Ca XX (Ly Fe XXV (He Cr XXIII (He Ar XVII (He Ar XVIII (Ly Mn XXIV (He Ca XIX / XX Yo u are h ere ! 1 km = 103 m Yo u are h ere ! (somewhere behind…) 107 m Yo u are h ere ! (and this is the Moon) 109 m ≃3.3 light seconds Yo u are h ere ! 1012 m ≃55.5 light minutes 1013 m 1014 m Yo u are h ere ! ≃4 light days 1013 m Yo u are h ere ! 1014 m 1017 m ≃10.6 light years 1021 m Yo u are h ere ! ≃106 000 light years 1 million ly Yo u are h ere ! The Local Group Andromeda (M31) 1 million ly Yo u are h ere ! The Local Group Triangulum (M33) 1 million ly Yo u are h ere ! The Local Group 10 millions ly The Virgo Supercluster Virgo cluster 10 millions ly The Virgo Supercluster M87 Virgo cluster 10 millions ly The Virgo Supercluster 2dFGRS Survey The large scale structure of the universe Abell 2199 (429 000 000 light years) Abell 2029 (1.1 billion light years) Abell 2029 (1.1 billion light years) Abell 1689 Abell 1689 (2.2 billion light years) Les amas de galaxies 53 Light emits at optical “colors”… …but also in infrared, radio, …and X-ray! Light emits at optical “colors”… …but also in infrared, radio, …and X-ray! Light emits at optical “colors”… -
Hierarchical Star Formation in Nearby Galaxies? M
Astronomy & Astrophysics manuscript no. Rodriguez_2020_corr ©ESO 2020 October 28, 2020 Hierarchical star formation in nearby galaxies? M. J. Rodríguez1??, G. Baume1; 2 and C. Feinstein1; 2 1 Instituto de Astrofísica de La Plata (CONICET-UNLP), Paseo del bosque S/N, La Plata (B1900FWA), Argentina, 2 Facultad de Ciencias Astronómicas y Geofísicas - Universidad Nacional de La Plata, Paseo del bosque S/N, La Plata (B1900FWA), Argentina Accepted XXX. Received YYY; in original form ZZZ ABSTRACT Aims. The purpose of this work is to study the properties of the spatial distribution of the young population in three nearby galaxies in order to better understand the first stages of star formation. Methods. We used ACS/HST photometry and the "path-linkage criterion" in order to obtain a catalog of young stellar groups (YSGs) in the galaxy NGC 2403. We studied the internal distribution of stars in these YSGs using the Q parameter. We extended these analyses to the YSGs detected in in NGC 300 and NGC 253 our previous works. We built the young stars’ density maps for these three galaxies. Through these maps, we were able to identify and study young stellar structures on larger scales. Results. We found 573 YSGs in the galaxy NGC 2403, for which we derived their individual sizes, densities, luminosity function, and other fundamental characteristics. We find that the vast majority of the YSGs in NGC 2403, NGC 300 and NGC 253 present inner clumpings, following the same hierarchical behavior that we observed in the young stellar structures on larger scales in these galaxies. We derived values of the fractal dimension for these structures between ∼ 1.5 and 1.6. -
Infrared Spectroscopy of Nearby Radio Active Elliptical Galaxies
The Astrophysical Journal Supplement Series, 203:14 (11pp), 2012 November doi:10.1088/0067-0049/203/1/14 C 2012. The American Astronomical Society. All rights reserved. Printed in the U.S.A. INFRARED SPECTROSCOPY OF NEARBY RADIO ACTIVE ELLIPTICAL GALAXIES Jeremy Mould1,2,9, Tristan Reynolds3, Tony Readhead4, David Floyd5, Buell Jannuzi6, Garret Cotter7, Laura Ferrarese8, Keith Matthews4, David Atlee6, and Michael Brown5 1 Centre for Astrophysics and Supercomputing Swinburne University, Hawthorn, Vic 3122, Australia; [email protected] 2 ARC Centre of Excellence for All-sky Astrophysics (CAASTRO) 3 School of Physics, University of Melbourne, Melbourne, Vic 3100, Australia 4 Palomar Observatory, California Institute of Technology 249-17, Pasadena, CA 91125 5 School of Physics, Monash University, Clayton, Vic 3800, Australia 6 Steward Observatory, University of Arizona (formerly at NOAO), Tucson, AZ 85719 7 Department of Physics, University of Oxford, Denys, Oxford, Keble Road, OX13RH, UK 8 Herzberg Institute of Astrophysics Herzberg, Saanich Road, Victoria V8X4M6, Canada Received 2012 June 6; accepted 2012 September 26; published 2012 November 1 ABSTRACT In preparation for a study of their circumnuclear gas we have surveyed 60% of a complete sample of elliptical galaxies within 75 Mpc that are radio sources. Some 20% of our nuclear spectra have infrared emission lines, mostly Paschen lines, Brackett γ , and [Fe ii]. We consider the influence of radio power and black hole mass in relation to the spectra. Access to the spectra is provided here as a community resource. Key words: galaxies: elliptical and lenticular, cD – galaxies: nuclei – infrared: general – radio continuum: galaxies ∼ 1. INTRODUCTION 30% of the most massive galaxies are radio continuum sources (e.g., Fabbiano et al. -
Stellar Tidal Streams As Cosmological Diagnostics: Comparing Data and Simulations at Low Galactic Scales
RUPRECHT-KARLS-UNIVERSITÄT HEIDELBERG DOCTORAL THESIS Stellar Tidal Streams as Cosmological Diagnostics: Comparing data and simulations at low galactic scales Author: Referees: Gustavo MORALES Prof. Dr. Eva K. GREBEL Prof. Dr. Volker SPRINGEL Astronomisches Rechen-Institut Heidelberg Graduate School of Fundamental Physics Department of Physics and Astronomy 14th May, 2018 ii DISSERTATION submitted to the Combined Faculties of the Natural Sciences and Mathematics of the Ruperto-Carola-University of Heidelberg, Germany for the degree of DOCTOR OF NATURAL SCIENCES Put forward by GUSTAVO MORALES born in Copiapo ORAL EXAMINATION ON JULY 26, 2018 iii Stellar Tidal Streams as Cosmological Diagnostics: Comparing data and simulations at low galactic scales Referees: Prof. Dr. Eva K. GREBEL Prof. Dr. Volker SPRINGEL iv NOTE: Some parts of the written contents of this thesis have been adapted from a paper submitted as a co-authored scientific publication to the Astronomy & Astrophysics Journal: Morales et al. (2018). v NOTE: Some parts of this thesis have been adapted from a paper accepted for publi- cation in the Astronomy & Astrophysics Journal: Morales, G. et al. (2018). “Systematic search for tidal features around nearby galaxies: I. Enhanced SDSS imaging of the Local Volume". arXiv:1804.03330. DOI: 10.1051/0004-6361/201732271 vii Abstract In hierarchical models of galaxy formation, stellar tidal streams are expected around most galaxies. Although these features may provide useful diagnostics of the LCDM model, their observational properties remain poorly constrained. Statistical analysis of the counts and properties of such features is of interest for a direct comparison against results from numeri- cal simulations. In this work, we aim to study systematically the frequency of occurrence and other observational properties of tidal features around nearby galaxies. -
Searching for Diffuse Light in the M96 Group
Draft version June 30, 2016 Preprint typeset using LATEX style emulateapj v. 5/2/11 SEARCHING FOR DIFFUSE LIGHT IN THE M96 GALAXY GROUP Aaron E. Watkins1, J. Christopher Mihos1,Paul Harding1,John J. Feldmeier2 Draft version June 30, 2016 ABSTRACT We present deep, wide-field imaging of the M96 galaxy group (also known as the Leo I Group). Down to surface brightness limits of µB = 30:1 and µV = 29:5, we find no diffuse, large-scale optical counterpart to the “Leo Ring”, an extended HI ring surrounding the central elliptical M105 (NGC 3379). However, we do find a number of extremely low surface-brightness (µB & 29) small-scale streamlike features, possibly tidal in origin, two of which may be associated with the Ring. In addition we present detailed surface photometry of each of the group’s most massive members – M105, NGC 3384, M96 (NGC 3368), and M95 (NGC 3351) – out to large radius and low surface brightness, where we search for signatures of interaction and accretion events. We find that the outer isophotes of both M105 and M95 appear almost completely undisturbed, in contrast to NGC 3384 which shows a system of diffuse shells indicative of a recent minor merger. We also find photometric evidence that M96 is accreting gas from the HI ring, in agreement with HI data. In general, however, interaction signatures in the M96 Group are extremely subtle for a group environment, and provide some tension with interaction scenarios for the formation of the Leo HI Ring. The lack of a significant component of diffuse intragroup starlight in the M96 Group is consistent with its status as a loose galaxy group in which encounters are relatively mild and infrequent. -
1. Introduction
THE ASTROPHYSICAL JOURNAL SUPPLEMENT SERIES, 122:109È150, 1999 May ( 1999. The American Astronomical Society. All rights reserved. Printed in U.S.A. GALAXY STRUCTURAL PARAMETERS: STAR FORMATION RATE AND EVOLUTION WITH REDSHIFT M. TAKAMIYA1,2 Department of Astronomy and Astrophysics, University of Chicago, Chicago, IL 60637; and Gemini 8 m Telescopes Project, 670 North Aohoku Place, Hilo, HI 96720 Received 1998 August 4; accepted 1998 December 21 ABSTRACT The evolution of the structure of galaxies as a function of redshift is investigated using two param- eters: the metric radius of the galaxy(Rg) and the power at high spatial frequencies in the disk of the galaxy (s). A direct comparison is made between nearby (z D 0) and distant(0.2 [ z [ 1) galaxies by following a Ðxed range in rest frame wavelengths. The data of the nearby galaxies comprise 136 broad- band images at D4500A observed with the 0.9 m telescope at Kitt Peak National Observatory (23 galaxies) and selected from the catalog of digital images of Frei et al. (113 galaxies). The high-redshift sample comprises 94 galaxies selected from the Hubble Deep Field (HDF) observations with the Hubble Space Telescope using the Wide Field Planetary Camera 2 in four broad bands that range between D3000 and D9000A (Williams et al.). The radius is measured from the intensity proÐle of the galaxy using the formulation of Petrosian, and it is argued to be a metric radius that should not depend very strongly on the angular resolution and limiting surface brightness level of the imaging data. It is found that the metric radii of nearby and distant galaxies are comparable to each other. -
Lateinischer Name: Deutscher Name: Hya Hydra Wasserschlange
Lateinischer Name: Deutscher Name: Hya Hydra Wasserschlange Atlas Karte (2000.0) Kulmination um Cambridge 10, 16, Mitternacht: Star Atlas 17 12, 13, Sky Atlas Benachbarte Sternbilder: 20, 21 Ant Cnc Cen Crv Crt Leo Lib 9. Februar Lup Mon Pup Pyx Sex Vir Deklinationsbereic h: -35° ... 7° Fläche am Himmel: 1303° 2 Mythologie und Geschichte: Bei der nördlichen Wasserschlange überlagern sich zwei verschiedene Bilder aus der griechischen Mythologie. Das erste Bild zeugt von der eher harmlosen Wasserschlange aus der Geschichte des Raben : Der Rabe wurde von Apollon ausgesandt, um mit einem goldenen Becher frisches Quellwasser zu holen. Stattdessen tat sich dieser an Feigen gütlich und trug bei seiner Rückkehr die Wasserschlange in seinen Fängen, als angebliche Begründung für seine Verspätung. Um jedermann an diese Untat zu erinnern, wurden der Rabe samt Becher und Wasserschlange am Himmel zur Schau gestellt. Von einem ganz anderen Schlag war die Wasserschlange, mit der Herakles zu tun hatte: In einem Sumpf in der Nähe von Lerna, einem See und einer Stadt an der Küste von Argo, hauste ein unsagbar gefährliches und grässliches Untier. Diese Schlange soll mehrere Köpfe gehabt haben. Fünf sollen es gewesen sein, aber manche sprechen auch von sechs, neun, ja fünfzig oder hundert Köpfen, aber in jedem Falle war der Kopf in der Mitte unverwundbar. Fürchterlich war es, da diesen grässlichen Mäulern - ob die Schlange nun schlief oder wachte - ein fauliger Atem, ein Hauch entwich, dessen Gift tödlich war. Kaum schlug ein todesmutiger Mann dem Untier einen Kopf ab, wuchsen auf der Stelle zwei neue Häupter hervor, die noch furchterregender waren. Eurystheus, der König von Argos, beauftragte Herakles in seiner zweiten Aufgabe diese lernäische Wasserschlange zu töten. -
Galaxy Transformation in Clusters
GGaalalaxxyy TTrarannssfoformrmaatiotionn inin CClulusstetersrs Coma CL0939 z=0.41 U. Fritze, PostGrad UH 2008 FFroromm GGrorouuppss toto CluClusterssters The Local Group : 35 members around Milky Way & M31 within 1 Mpc Nearby groups : Sculptor group : 6 members D~1.8 Mpc M81 group : 8 members D~3.1 Mpc Centaurus group : 17 members D~3.5 Mpc M101 group : 5 members D~7.7 Mpc M66+M96 group : 10 members D~9.4 Mpc NGC 1023 group : 6 members D~9.6 Mpc Census very incomplete : low – luminosity dwarfs like Sag dSph cannot be detected beyond our Local Group galaxy group <50 members, galaxy cluster >50 members U. Fritze, PostGrad UH 2008 LLoocalcal GGalaxyalaxy CluClusterssters Virgo (W. Herschel 18th century) 10° × 10° D~16 Mpc ~ 250 normal galaxies > 2000 dwarf galaxies irregular cluster : 2 big Es: M87 & NGC 4479, not particularly rich Coma : regular rich cluster (+ substructure) D~ 90 Mpc ~ 10,000 galaxies U. Fritze, PostGrad UH 2008 AbAbellell CataloCatalogg ooff GGalaxyalaxy CluClusterssters G. Abell 1958: POSS northern sky w/o Milky Way disk (extinction) Cluster := >50 members within m3 and m3+2 mag, rd m3 := mag of 3 brightest member, within angular radius qA=1.7'/z, z=redshift estimate (from 10th brightest galaxy assumed to be universal) 1682 galaxy clusters within 0.02 < z < 0.2 (z>0.02 --> cluster fits on ~6° ´ 6° POSS plate, z<0.2 --> sensitivity limit of POSS plates) extended to include 4076 clusters by Abell, Corwin, Olowin 1989 both catalogs not free from projection effects !!! U. Fritze, PostGrad UH 2008 GGalaxyalaxy CluClusterssters Galaxy Clusters : Rcl~ 2 - 10 Mpc, Ngal = 50 . -
April Constellations of the Month
April Constellations of the Month Leo Small Scope Objects: Name R.A. Decl. Details M65! A large, bright Sa/Sb spiral galaxy. 7.8 x 1.6 arc minutes, magnitude 10.2. Very 11hr 18.9m +13° 05’ (NGC 3623) high surface brighness showing good detail in medium sized ‘scopes. M66! Another bright Sb galaxy, only 21 arc minutes from M65. Slightly brighter at mag. 11hr 20.2m +12° 59’ (NGC 3627) 9.7, measuring 8.0 x 2.5 arc minutes. M95 An easy SBb barred spiral, 4 x 3 arc minutes in size. Magnitude 10.5, with 10hr 44.0m +11° 42’ a bright central core. The bar and outer ring of material will require larger (NGC 3351) aperature and dark skies. M96 Another bright Sb spiral, about 42 arc minutes east of M95, but larger and 10hr 46.8m +11° 49’ (NGC 3368) brighter. 6 x 4 arc minutes, magnitude 10.1. Located about 48 arc minutes NNE of M96. This small elliptical galaxy measures M105 only 2 x 2.1 arc minutes, but at mag. 10.3 has very high surface brightness. 10hr 47.8m +12° 35’ (NGC 3379) Look for NGC 3384! (110NGC) and NGC 3389 (mag 11.0 and 12.2) which form a small triangle with M105. NGC 3384! 10hr 48.3m +12° 38’ See comment for M105. The brightest galaxy in Leo, this Sb/Sc spiral galaxy shines at mag. 9.5. Look for NGC 2903!! 09hr 32.2m +21° 30’ a hazy patch 11 x 4.7 arc minutes in size 1.5° south of l Leonis. -
Astronomical Evidence for an Alternative to Dark Matter?
Astronomical Evidence for an Alternative to Dark Matter? by Alphonsus J. Fagan St. John's NL, Canada Abstract Unexplained gravitational potentials in deep space have been generally attributed to dark matter. This paper explores an alternative that unites the concepts of dark matter and dark energy, and is rooted in the idea that space is a tangible ‘substance’ that is being created at different rates at different locations. The concept of congenital gravitational structure ('structural gravity') is introduced and the possibility that antimatter experiences anti-gravity is discussed. Among other things, the conjectures predict the phenomenon of 'inverse gravitational lensing' and possible examples are identified — in particular as associated with the peculiar galaxy known as Hoag's Object. The conjectures also offer possible explanations for a number of poorly understood phenomena, including: the antimatter cloud; dark matter halos; the vacuum catastrophe; counter-rotating galaxies; the Hubble radius; and, large scale cosmic features. Although the ideas are mainly discussed at a conceptual level, the proposed model also makes a number of testable predictions. Keywords: cosmology; modified gravity; time; dark energy; dark matter; antimatter; diffuse x-ray background; ring galaxies; Hoag's Object; vacuum catastrophe; cosmic horizon Author’s Note: The ideas presented herein are a condensed form of a larger model presented in a (2020) book “Mind Openers 2.0: A Conceptual Reinterpretation of Modern Physics”: currently available at Mind Openers 2.0 on Amazon 1. Introduction 1.1 Unexplained Gravity As first pointed out by Fritz Zwicky in the 1930s, and later confirmed by Vera Rubin and Kent Ford in the 1960s and 70s, the amount of ordinary matter in galaxies and intergalactic gas and dust, does not provide sufficient gravitational potential to account for galactic rotation curves, or the velocities of galaxies within clusters. -
Guide Du Ciel Profond
Guide du ciel profond Olivier PETIT 8 mai 2004 2 Introduction hjjdfhgf ghjfghfd fg hdfjgdf gfdhfdk dfkgfd fghfkg fdkg fhdkg fkg kfghfhk Table des mati`eres I Objets par constellation 21 1 Androm`ede (And) Andromeda 23 1.1 Messier 31 (La grande Galaxie d'Androm`ede) . 25 1.2 Messier 32 . 27 1.3 Messier 110 . 29 1.4 NGC 404 . 31 1.5 NGC 752 . 33 1.6 NGC 891 . 35 1.7 NGC 7640 . 37 1.8 NGC 7662 (La boule de neige bleue) . 39 2 La Machine pneumatique (Ant) Antlia 41 2.1 NGC 2997 . 43 3 le Verseau (Aqr) Aquarius 45 3.1 Messier 2 . 47 3.2 Messier 72 . 49 3.3 Messier 73 . 51 3.4 NGC 7009 (La n¶ebuleuse Saturne) . 53 3.5 NGC 7293 (La n¶ebuleuse de l'h¶elice) . 56 3.6 NGC 7492 . 58 3.7 NGC 7606 . 60 3.8 Cederblad 211 (N¶ebuleuse de R Aquarii) . 62 4 l'Aigle (Aql) Aquila 63 4.1 NGC 6709 . 65 4.2 NGC 6741 . 67 4.3 NGC 6751 (La n¶ebuleuse de l’œil flou) . 69 4.4 NGC 6760 . 71 4.5 NGC 6781 (Le nid de l'Aigle ) . 73 TABLE DES MATIERES` 5 4.6 NGC 6790 . 75 4.7 NGC 6804 . 77 4.8 Barnard 142-143 (La tani`ere noire) . 79 5 le B¶elier (Ari) Aries 81 5.1 NGC 772 . 83 6 le Cocher (Aur) Auriga 85 6.1 Messier 36 . 87 6.2 Messier 37 . 89 6.3 Messier 38 . -
The Extragalactic Distance Scale
The Extragalactic Distance Scale Published in "Stellar astrophysics for the local group" : VIII Canary Islands Winter School of Astrophysics. Edited by A. Aparicio, A. Herrero, and F. Sanchez. Cambridge ; New York : Cambridge University Press, 1998 Calibration of the Extragalactic Distance Scale By BARRY F. MADORE1, WENDY L. FREEDMAN2 1NASA/IPAC Extragalactic Database, Infrared Processing & Analysis Center, California Institute of Technology, Jet Propulsion Laboratory, Pasadena, CA 91125, USA 2Observatories, Carnegie Institution of Washington, 813 Santa Barbara St., Pasadena CA 91101, USA The calibration and use of Cepheids as primary distance indicators is reviewed in the context of the extragalactic distance scale. Comparison is made with the independently calibrated Population II distance scale and found to be consistent at the 10% level. The combined use of ground-based facilities and the Hubble Space Telescope now allow for the application of the Cepheid Period-Luminosity relation out to distances in excess of 20 Mpc. Calibration of secondary distance indicators and the direct determination of distances to galaxies in the field as well as in the Virgo and Fornax clusters allows for multiple paths to the determination of the absolute rate of the expansion of the Universe parameterized by the Hubble constant. At this point in the reduction and analysis of Key Project galaxies H0 = 72km/ sec/Mpc ± 2 (random) ± 12 [systematic]. Table of Contents INTRODUCTION TO THE LECTURES CEPHEIDS BRIEF SUMMARY OF THE OBSERVED PROPERTIES OF CEPHEID