DOCSLIB.ORG

Lecture Four: Scaling Relations Late Type Galaxies… Masses of Spiral

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
Lecture Four: Scaling Relations Late Type Galaxies… Masses of Spiral Lecture Four: Scaling Relations Measuring galaxy properties contd. One of the main uses of astrophysical surface photometry is for the study of parameter correlations and scaling laws. These contain valuable information about galaxy formation & evolution Kormendy & Djorgovski 1989 ARAA 27 235 Tuesday 11th Feb 1 2 Masses of Spiral galaxies Surface Brightness profiles sample the distribution of luminous matter in a galaxy. This does not necessarily tell us about the mass of the galaxy - due to DARK MATTER. Late Type Galaxies… HI rotation curves allow TOTAL mass determination. Battaglia et al. 2006 A&A, 447, 49 3 4 Rotation Curves of Spiral Galaxies Bosma 1981 Masses of Spiral galaxies correlations : The constant rotational velocities in the outer regions - suggest that mass increases linearly • increasing L rotation curves tend with distance from the centre. In stark contrast to the light distribution, which decreases B exponentially over the same distance. to rise more rapidly with distance from centre and peak at higher This means a rapidly increasing mass-to-light ration (M/L) and a hidden dark matter halo in maximum velocity (Vmax). spiral galaxies (Bosma 1981). • for equal LB spirals of earlier type have larger Vmax. The fact that galaxies of different Hubble types, and therefore different bulge-to-disk luminosity ratios, exhibit rotation curves that are very similar in form if not in amplitude • within a given Hubble type more suggests that the shapes of the gravitational potential do not necessarily follow the luminous galaxies have larger Vmax. distribution of luminous matter. • for a given value of Vmax the rotation curves tend to rise slightly more rapidly with radius for earlier type galaxies. •Vmax is significantly lower in Irrs 5 6 Tully-Fisher: late type galaxies Tully-Fisher with rotation curve A relationship exists between the luminosity of a spiral galaxy and its maximum Three kinds of rotation curves rotation velocity. Good distance indicator! Observed as absolute magnitude and HI profile width Example of global HI profile Vflat not V < V Vflat = Vmax flat max reached? Tully & Fisher 1977 Disk Mass dominates ! Verheijen 2001 7 8 width of global HI profile Trends in M/L with galaxy parameters B B M/L NOT constant! K peak velocity of HI K rotation curve Tightest relation is between M and Vflat K, Absolute mag. K, surface brightness = Relation between the stellar mass (luminosity) and the DM halo mass B B The star formation and the chemical enrichment history determine both the stellar M/L amplitude of flat ratio and galaxy color part of HI rotation curve K K Verheijen 2001 Bell & de Jong 2001 gas-fraction galaxy colour More scatter in B due to stellar pop effects 9 10 Converting luminosity to mass Tully-Fisher with stellar mass IMF (initial mass function) Ψ(m, t), number of stars formed per unit volume at t=0 -α often approximated as a power law: Ψ(m) dm = Ψ0 m LF (luminosity function) currently observed number of stars observed per unit luminosity per unit volume PDMF (present day mass function) number of stars observed today per unit mass per unit volume. This needs to be corrected for the time evolution of the IMF up to the present day, low mass, IMF long lived stars PDMF Star Relations with BRIK colours and assuming a Salpeter IMF are used to convert the Formation magnitude-dependent dust-corrected magnitudes into stellar masses, using the dust- high mass, corrected B-R color as input. short lived History stars Bell & de Jong 2001 Kroupa, Tout & Gilmore 1993 MNRAS, 262, 545 11 12 Tully-Fisher at low masss The slope change in the TF is reconciled when the gas mass is taken into account: M = A * V b Break, for small • d c galaxies b=3.98 ± 0.12 Gas significant, large component in small galaxies BARYONIC TULLY-FISHER McGaugh et al. 2005 13 14 Early Type Galaxies… Families of Ellipsoidal stellar systems… 15 16 Masses of Elliptical galaxies Masses of Elliptical galaxies Elliptical Galaxies: application of virial theorem, assuming Using globular clusters as tracers, the line-of-sight velocity dispersion in Elliptical isotropic stellar distribution galaxies remains remarkably constant out to the limits of observation. This has the same explanation as flat rotation curves in HI. To bind globular clusters with large velocity dispersions at large radii means that the mass within R must increase proportional to R. Large Dark Matter haloes also in Elliptical Galaxies Côte et al. 2003 ApJ, 591, 850 17 18 Shapes of Elliptical galaxies Internal dynamics of Ellipticals Flattening caused by rotation can be tested by measuring the mean velocities and velocity dispersions of the stars through out the body of a galaxy. These measurements can be compared with the rotation and internal velocity dispersions expected if the flattening can be attributed to rotation. Low luminosity Ellipticals and bulges rotate rapidly and have nearly isotropic velocity Solid line: amount of rotation dispersions and are flattened by rotation (solid necessary to black points + crosses). account for observed ellipticity of galaxy relative Bright Ellipticals rotate slowly and are pressure to σ of stars. supported and owe their shapes to velocity anisotropy (open circles) This could be explained by proto-galaxies acquiring angular momentum through tidal torques and then if mergers produce brighter ellipticals the rotation gets scrambled in the It might be thought that the internal dynamics of elliptical galaxies would be relatively process. simple - the surface brightness distributions appear to be ellipsoidal, with a range of Ellipticals rotate too slowly for centrifugal forces flattenings, which it might be thought could be attributed to rotation. to be the causes of their observed flattening. from Davies et al. 1983 19 20 The Faber-Jackson Relation Multi-parameter correlations: Looking for correlations in the observed properties of Elliptical galaxies the Fundamental Plane Faber & Jackson 1976: strong correlation between luminosity (L) and central velocity dispersion (σ): A break through in our understanding of scaling laws came from large homogeneous data sets (from CCDs & long-slit Taking log of both sides, relation in terms of M . A natural consequence of the virial theorem. B spectroscopy), and the application of statistical tools. Plenty of scatter, and the slope of the relation is different than the virial plane - means correlation in a 3D space and we see this space theorem. with three parameters that “see” the correlation from This was assumed to indicate a missing different angles. parameter… and there was originally a lot of debate about what was the missing parameter.. using data from Bender et al. 92 21 22 Ellipticals: Fundamental Plane Projections of Fundamental Plane of Ellipticals & Bulges Radius derived from Tilt to plane leads surface brightness to scatter. profiles, e.g., core or effective radius. Radius Luminosity Faber-Jackson Radius Velocity Dispersion Mean Surface Brightness physical meaning of these measurements links Observed “Cooling Diagram” from galaxy Meanto formationSurface Brightness theory! Velocity Dispersion formation theory (virial temprature vs. density) Radius Plane edge-on plane face-on position of galaxy inMean Surface Brightness this diagram relates to amount of dissipation Velocity Dispersion Combined Velocity Dispersion & surface brightness during its formation. Djorgovski & Davis 1987 23 24 Ellipticals: Fundamental Plane Measuring galaxy properties Radius Velocity Dispersion mean Surface Brightness with Sloan Digital Sky Survey (SDSS) Longair, chapter 3 Blanton & Moustakas 2009 ARAA 47 159 Reading is very important!! 25 26 Studying galaxies A galaxy can consist of hundreds of millions or billions of stars. It can contain considerable quantities of interstellar gas and dust and can be subject to environmental influences through interactions with other galaxies and intergalactic gas. It may be forming stars with a variety of rates. And it will contain dark matter and the dynamics of galaxies are largely dominated by this era of large galaxy surveys.... invisible dark component, the nature of which is unknown. Until recently the properties of galaxies were determined from meticulous morphological studies of samples of bright galaxies - encompassing a vast amount of detail. Now in the era of large surveys [e.g., hundreds of thousands of galaxies in the Sloan Digital Sky Survey (SDSS)] classification has to be simpler as the parameters have to be able to be automatically and consistently measured by computer. What these large surveys lack in detail they more than make up for with statistics. 28 27 28 2DF Galaxy Redshift Survey Millennium Galaxy Catalogue Imported Author Yesterday, 12:26 Reliable redshifts for 220k objects, mainly galaxies, brighter than a magnitude limit of bJ=19.45, cover an area of approximately 1500 square degrees http://www2.aao.gov.au/~TDFgg/ http://www.eso.org/~jliske/mgc/ 29 30 The Sloan Digital Sky Survey SLOAN - hardware The SDSS used a dedicated 2.5-m f/5 modified Ritchey-Chretien altitude- azimuth telescope located at Apache Point Observatory (2788m), New Mexico, USA. It is equipped with two powerful special-purpose instruments. The 120-megapixel camera which can image 1.5 square degrees of sky at a time. A pair of spectrographs fed by optical fibres measured spectra of (and hence distances to) more than 600 galaxies and quasars in a single observation. A custom-designed set of software pipelines kept pace with the enormous data flow from the telescope. Imager: 30 SITe/Tektronix 2048 by 2048 pixel CCDs: r, i, u, z, g filters. Drift scan mode: camera slowly reads CCD as data collected. spectrographs: in a single exposure ~600 spectra of galaxies to the spectroscopic limit of r’ ~ 18.2 over the field of the telescope. R~2000, λ3900-9100Å. 31 32 SLOAN - observing special Sloan filter system shows the strips on the sky observed by Sloan... the underlying contours are extinction from Galactic disk.
Load more

Recommended publications
  • The Detailed Properties of Leo V, Pisces II and Canes Venatici II
    Haverford College Haverford Scholarship Faculty Publications Astronomy 2012 Tidal Signatures in the Faintest Milky Way Satellites: The Detailed Properties of Leo V, Pisces II and Canes Venatici II David J. Sand Jay Strader Beth Willman Haverford College Dennis Zaritsky Follow this and additional works at: https://scholarship.haverford.edu/astronomy_facpubs Repository Citation Sand, David J., Jay Strader, Beth Willman, Dennis Zaritsky, Brian Mcleod, Nelson Caldwell, Anil Seth, and Edward Olszewski. "Tidal Signatures In The Faintest Milky Way Satellites: The Detailed Properties Of Leo V, Pisces Ii, And Canes Venatici Ii." The Astrophysical Journal 756.1 (2012): 79. Print. This Journal Article is brought to you for free and open access by the Astronomy at Haverford Scholarship. It has been accepted for inclusion in Faculty Publications by an authorized administrator of Haverford Scholarship. For more information, please contact [email protected]. The Astrophysical Journal, 756:79 (14pp), 2012 September 1 doi:10.1088/0004-637X/756/1/79 C 2012. The American Astronomical Society. All rights reserved. Printed in the U.S.A. TIDAL SIGNATURES IN THE FAINTEST MILKY WAY SATELLITES: THE DETAILED PROPERTIES OF LEO V, PISCES II, AND CANES VENATICI II∗ David J. Sand1,2,7, Jay Strader3, Beth Willman4, Dennis Zaritsky5, Brian McLeod3, Nelson Caldwell3, Anil Seth6, and Edward Olszewski5 1 Las Cumbres Observatory Global Telescope Network, 6740 Cortona Drive, Suite 102, Santa Barbara, CA 93117, USA; [email protected] 2 Department of Physics, Broida Hall,
    [Show full text]
  • 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.
    [Show full text]
  • Eight New Milky Way Companions Discovered in First­Year Dark Energy Survey Data
    Eight new Milky Way companions discovered in first-year Dark Energy Survey Data Article (Published Version) Romer, Kathy and The DES Collaboration, et al (2015) Eight new Milky Way companions discovered in first-year Dark Energy Survey Data. Astrophysical Journal, 807 (1). ISSN 0004- 637X This version is available from Sussex Research Online: http://sro.sussex.ac.uk/id/eprint/61756/ This document is made available in accordance with publisher policies and may differ from the published version or from the version of record. If you wish to cite this item you are advised to consult the publisher’s version. Please see the URL above for details on accessing the published version. Copyright and reuse: Sussex Research Online is a digital repository of the research output of the University. Copyright and all moral rights to the version of the paper presented here belong to the individual author(s) and/or other copyright owners. To the extent reasonable and practicable, the material made available in SRO has been checked for eligibility before being made available. Copies of full text items generally can be reproduced, displayed or performed and given to third parties in any format or medium for personal research or study, educational, or not-for-profit purposes without prior permission or charge, provided that the authors, title and full bibliographic details are credited, a hyperlink and/or URL is given for the original metadata page and the content is not changed in any way. http://sro.sussex.ac.uk The Astrophysical Journal, 807:50 (16pp), 2015 July 1 doi:10.1088/0004-637X/807/1/50 © 2015.
    [Show full text]
  • Kugelsternhaufen
    www.vds-astro.de ISSN 1615-0880 IV/2010 Nr. 35 Zeitschrift der Vereinigung der Sternfreunde e.V. Schwerpunktthema Kugelsternhaufen Klein, rund und plump! Die Botschaft von den Grundlagen der JPG-Foto- Seite 54 Sternen metrie Seite 87 Seite 111 [email protected] • www.astro-shop.com Tel.: 040/5114348 • Fax: 040/5114594 Eiffestr. 426 • 20537 Hamburg Astroart 4.0 Canon EOS 1000D Astro Photoshop Astronomy Die aktuellste Version Ab sofort erhalten Sie bei uns speziell für die Der Autor arbeitet seit fast 10 Jahren mit Photo- des bekannten Bildbe- Astronomie modizierte Canon EOS Kameras, shop, um seine Astrofotos zu bearbeiten. Die arbeitungspro- ab Lager und mit Garantie! dabei gemachten Erfahrungen hat er in diesem grammes gibt es jetzt Die 1000D Astro hat eine um den Faktor 5 speziell auf die Bedürfnisse des Amateurastro- mit interessanten höhere Rotempndlichkeit im Bereich von nomen zugeschnitte- neuen Funktionen. H-alpha nen Buch gesammelt. Moderne Dateifor- bzw. SII. Die behandelten The- men sind unter ande- mate wie DSLR-RAW Endlich rem: die technische werden unterstützt, können Ausstattung, Farbma- Bilder können Regionen nagement, Histo- durch automa- am Himmel gramme, Maskie- tische Sternfelderken- sichtbar rungstechniken, nung direkt überlagert werden, was die Bild- gemacht Addition mehrerer feldrotation vernachlässigbar macht. Auch die werden, die Bilder, Korrektur von Bearbeitung von Farbbildern wurde erweitert. vorher auf Astroaufnahmen nur ansatzweise Vignettierungen, Besonderes Augenmerk liegt auf der Erken- sichtbar waren oder im Himmelshintergrund Farbhalos, Deformationen oder nung und Behandlung von Pixelfehlern der schlicht 'abgesoen' sind. Somit stellt die EOS überbelichteten Sternen, LRGB und vieles Aufnahme-Chips. 1000D Astro eine preisgünstige Alternative zu mehr.
    [Show full text]
  • Arxiv:1508.03622V2 [Astro-Ph.GA] 6 Nov 2015 – 2 –
    Eight Ultra-faint Galaxy Candidates Discovered in Year Two of the Dark Energy Survey 1; 2;3; 4;5 6;7 6;7 8;4;5 A. Drlica-Wagner ∗, K. Bechtol y, E. S. Rykoff , E. Luque , A. Queiroz , Y.-Y. Mao , R. H. Wechsler8;4;5, J. D. Simon9, B. Santiago6;7, B. Yanny1, E. Balbinot10;7, S. Dodelson1;11, A. Fausti Neto7, D. J. James12, T. S. Li13, M. A. G. Maia7;14, J. L. Marshall13, A. Pieres6;7, K. Stringer13, A. R. Walker12, T. M. C. Abbott12, F. B. Abdalla15;16, S. Allam1, A. Benoit-L´evy15, G. M. Bernstein17, E. Bertin18;19, D. Brooks15, E. Buckley-Geer1, D. L. Burke4;5, A. Carnero Rosell7;14, M. Carrasco Kind20;21, J. Carretero22;23, M. Crocce22, L. N. da Costa7;14, S. Desai24;25, H. T. Diehl1, J. P. Dietrich24;25, P. Doel15, T. F. Eifler17;26, A. E. Evrard27;28, D. A. Finley1, B. Flaugher1, P. Fosalba22, J. Frieman1;11, E. Gaztanaga22, D. W. Gerdes28, D. Gruen29;30, R. A. Gruendl20;21, G. Gutierrez1, K. Honscheid31;32, K. Kuehn33, N. Kuropatkin1, O. Lahav15, P. Martini31;34, R. Miquel35;23, B. Nord1, R. Ogando7;14, A. A. Plazas26, K. Reil5, A. Roodman4;5, M. Sako17, E. Sanchez36, V. Scarpine1, M. Schubnell28, I. Sevilla-Noarbe36;20, R. C. Smith12, M. Soares-Santos1, F. Sobreira1;7, E. Suchyta31;32, M. E. C. Swanson21, G. Tarle28, D. Tucker1, V. Vikram37, W. Wester1, Y. Zhang28, J. Zuntz38 (The DES Collaboration) arXiv:1508.03622v2 [astro-ph.GA] 6 Nov 2015 { 2 { *[email protected] [email protected] 1Fermi National Accelerator Laboratory, P.
    [Show full text]
  • Universidad De Chile Facultad De Ciencias Físicas Y Matemáticas Departamento De Astronomía
    UNIVERSIDAD DE CHILE FACULTAD DE CIENCIAS FÍSICAS Y MATEMÁTICAS DEPARTAMENTO DE ASTRONOMÍA A COMPREHENSIVE PHOTOMETRIC STUDY OF THE MILKY WAY’S OUTER HALO SATELLITES TESIS PARA OPTAR AL GRADO DE DOCTOR EN CIENCIAS, MENCIÓN ASTRONOMÍA SEBASTIÁN ANDRÉS MARCHI LASCH PROFESOR GUÍA: RICARDO MUÑOZ VIDAL MIEMBROS DE LA COMISIÓN: JULIO CHANAMÉ DOMÍNGUEZ JAMES JENKINS PAULINA LIRA TEILLERY Este trabajo ha sido parcialmente financiado por CONICYT, DAS SANTIAGO DE CHILE 2020 RESUMEN DE LA MEMORIA PARA OPTAR AL TÍTULO DE DOCTOR EN CIENCIAS, MENCIÓN ASTRONOMÍA POR: SEBASTIÁN ANDRÉS MARCHI LASCH FECHA: 2020 PROF. GUÍA: RICARDO MUÑOZ VIDAL UN ESTUDIO FOTOMÉTRICO EXHAUSTIVO DE LOS OBJETOS SATÉLITES DEL HALO EXTERNO DE LA VÍA LÁCTEA. Una de las interrogantes más importantes en la astronomía Galáctica es entender los procesos responsables de la formación y evolución de la Vía Láctea. La mayor parte de la información para estudiar las etapas tempranas de formación Galáctica está contenida en el halo y sus subestructuras, dominadas por poblaciones estelares antiguas. En esta tesis, realizo un estudio fotométrico completo de los satélites del halo externo de la Vía Láctea. Ellos se agrupan en cúmulos globulares, galaxias enanas esferoidales y galaxias enanas ultra-débiles. Para esto, usé un set de datos que al mismo tiempo es profundo, de campo amplio y altamente homogéneo, a diferencia de los existentes en la literatura. En la primera parte de esta tesis, presento evidencia de una correlación entre el índice de Sérsic y el radio efectivo, seguida por una
    [Show full text]
  • Abenteuer Astronomie 13 | Februar/März 2018 Fokussiert
    Abenteuer Astronomie 13 | Februar/März 2018 fokussiert Titelbild: So stellt sich ein Künstler die Oberfläche des Planeten TRAPPIST-1f vor. Ob der Planet in rund 40 Lichtjahren Entfernung aber tatsächlich so aussieht, weiß man noch nicht. NASA/JPL-Caltech REDAKTION IM EINSATZ BoHeTa 2017 Es gibt wohl kaum einen Ort, wo man sich besser über die Möglichkeiten der modernen Amateurastronomie und die Kreativität in der Szene informieren könnte, als die alljähr- Stefan Deiters liche Bochumer Herbsttagung (»BoHeTa«). Die 36. Ausga- Chefredakteur be, erstmals seit Jahren in einem anderen Hörsaal, dessen Eingang auf dem komplex dreidimensionalen Uni-Campus . t nur dank üppiger Ausschilderung durch die Veranstalter g zu finden war, machte da keine Ausnahme. Das Potpourri Liebe Leserinnen, liebe Leser, der Vorträge in den neun Stunden des 11. November 2017 gibt es Leben auf anderen Planeten oder Monden? Diese reichte von originellen Lösungen bei besonders preisgüns- Frage beschäftigt die Wissenschaft und Öffentlichkeit nicht tigem Sternwarten-Bau über Missverständnisse bei Po- ist untersa erst, seit wir in Science-Fiction-Filmen regelmäßig mit außer- g larlichtern bis zu Planetenforschung und Astrophysik auf irdischen Lebensformen konfrontiert werden. Deren Ausse- Profi-Niveau – aber von Amateur- oder Schulastronomen in hen entspringt der Fantasie der Autoren – die Wissenschaft reitun Eigenregie durchgeführt. ist noch nicht soweit, hier irgendwelche konkreten Aussagen b Dazu gehörte zum Beispiel die Messung von Lichtkurven machen zu können. Für unseren Hauptartikel hat der Astro- des Zwergplaneten Haumea in Farbe, die eine regelrech- biologe Johannes Leitner den gegenwärtigen Wissensstand zu- te »Kartierung« des Football-förmigen Körpers im Kui- sammengefasst (Seite 16). Ergänzt wird der Artikel durch ein pergürtel inklusive bunter Flecken ermöglichte.
    [Show full text]
  • Open Research Online Oro.Open.Ac.Uk
    Open Research Online The Open University’s repository of research publications and other research outputs Investigating Exoplanets and Transients Using Small-Aperture Telescopes Thesis How to cite: Busuttil, Richard (2017). Investigating Exoplanets and Transients Using Small-Aperture Telescopes. PhD thesis The Open University. For guidance on citations see FAQs. c 2016 The Author https://creativecommons.org/licenses/by-nc-nd/4.0/ Version: Version of Record Link(s) to article on publisher’s website: http://dx.doi.org/doi:10.21954/ou.ro.0000c2c4 Copyright and Moral Rights for the articles on this site are retained by the individual authors and/or other copyright owners. For more information on Open Research Online’s data policy on reuse of materials please consult the policies page. oro.open.ac.uk Investigating Exoplanets and Transients Using Small-Aperture Telescopes Submitted for the degree of Doctor of Philosophy in Astronomy and Astrophysics Richard Busuttil MPhys (Hons) Supervisors: Dr. Ulrich Kolb, Dr. Carole Haswell The Open University Submitted September 2016 Abstract This work characterises PIRATE’s primary camera, the SBIG STX-16803, as well as assessing the usefulness and impact of a small-aperture semi-autonomous facility in Mallorca for exoplanet studies and studies of transient sources. Additionally, a method for exploring the Roche lobe of an exoplanet and the effects this has on the shape and density of the planet is also described. PIRATE is a small aperture photometric facility that can be operated remotely or autonomously, is constructed from commercially available hardware and utilised by The Open University for research, education and outreach.
    [Show full text]
  • Arxiv:1508.03622V2 [Astro-Ph.GA] 6 Nov 2015
    SLAC-PUB-16631 Eight Ultra-faint Galaxy Candidates Discovered in Year Two of the Dark Energy Survey 1; 2;3; 4;5 6;7 6;7 8;4;5 A. Drlica-Wagner ∗, K. Bechtol y, E. S. Rykoff , E. Luque , A. Queiroz , Y.-Y. Mao , R. H. Wechsler8;4;5, J. D. Simon9, B. Santiago6;7, B. Yanny1, E. Balbinot10;7, S. Dodelson1;11, A. Fausti Neto7, D. J. James12, T. S. Li13, M. A. G. Maia7;14, J. L. Marshall13, A. Pieres6;7, K. Stringer13, A. R. Walker12, T. M. C. Abbott12, F. B. Abdalla15;16, S. Allam1, A. Benoit-L´evy15, G. M. Bernstein17, E. Bertin18;19, D. Brooks15, E. Buckley-Geer1, D. L. Burke4;5, A. Carnero Rosell7;14, M. Carrasco Kind20;21, J. Carretero22;23, M. Crocce22, L. N. da Costa7;14, S. Desai24;25, H. T. Diehl1, J. P. Dietrich24;25, P. Doel15, T. F. Eifler17;26, A. E. Evrard27;28, D. A. Finley1, B. Flaugher1, P. Fosalba22, J. Frieman1;11, E. Gaztanaga22, D. W. Gerdes28, D. Gruen29;30, R. A. Gruendl20;21, G. Gutierrez1, K. Honscheid31;32, K. Kuehn33, N. Kuropatkin1, O. Lahav15, P. Martini31;34, R. Miquel35;23, B. Nord1, R. Ogando7;14, A. A. Plazas26, K. Reil5, A. Roodman4;5, M. Sako17, E. Sanchez36, V. Scarpine1, M. Schubnell28, I. Sevilla-Noarbe36;20, R. C. Smith12, M. Soares-Santos1, F. Sobreira1;7, E. Suchyta31;32, M. E. C. Swanson21, G. Tarle28, D. Tucker1, V. Vikram37, W. Wester1, Y. Zhang28, J. Zuntz38 (The DES Collaboration) arXiv:1508.03622v2 [astro-ph.GA] 6 Nov 2015 This material is based upon work supported by the U.S.
    [Show full text]
  • A Megacam Survey of Outer Halo Satellites. IV. Two Foreground
    DRAFT VERSION OCTOBER 21, 2018 Preprint typeset using LATEX style emulateapj v. 5/2/11 A MEGACAM SURVEY OF OUTER HALO SATELLITES. IV. TWO FOREGROUND POPULATIONS POSSIBLY ASSOCIATED WITH THE MONOCEROS SUBSTRUCTURE IN THE DIRECTION OF NGC 2419 AND KOPOSOV 21 JULIO A. CARBALLO-BELLO2 ,RICARDO R. MUÑOZ 2 ,JEFFREY L. CARLIN 3 ,PATRICK CÔTÉ4 ,MARLA GEHA5 ,JOSHUA D. SIMON6 , S. G. DJORGOVSKI7 Draft version October 21, 2018 ABSTRACT The origin of the Galactic halo stellar structure known as the Monoceros ring is still under debate. In this work, we study that halo substructure using deep CFHT wide-field photometry obtained for the globular clusters NGC 2419 and Koposov 2, where the presence of Monoceros becomes significant because of their coincident projected position. Using Sloan Digital Sky Survey photometry and spectroscopy in the area surrounding these globulars and beyond, where the same Monoceros population is detected, we conclude that a second feature, not likely to be associated with Milky Way disk stars along the line-of-sight, is present as foreground population. Our analysis suggests that the Monoceros ring might be composed of an old stellar population of age t ∼ 9 Gyr and a new component ∼ 4 Gyr younger at the same heliocentric distance. Alternatively, this detection might be associated with a second wrap of Monoceros in that direction of the sky and also indicate a metallicity spread in the ring. The detection of such a low-density feature in other sections of this halo substructure will shed light on its nature. Subject headings: Galaxy: structure, halo, globular clusters: general 1.
    [Show full text]
  • Science Case for a Wide Field-Of-View Very-High-Energy Gamma-Ray Observatory in the Southern Hemisphere
    Science Case for a Wide Field-of-View Very-High-Energy Gamma-Ray Observatory in the Southern Hemisphere A. Albert1, R. Alfaro2 H. Ashkar3, C. Alvarez4,4 J.Alvarez´ 5, J.C. Arteaga-Vel´azquez5, H. A. Ayala Solares6, R. Arceo4, J.A. Bellido7, S. BenZvi8, T. Bretz9, C.A. Brisbois10, A.M. Brown11, F. Brun3, K.S. Caballero-Mora4, A. Carosi12, A. Carrami~nana13, S. Casanova14;15, P.M. Chadwick11, G. Cotter16, S. Couti~no De Le´on13, P. Cristofari17;18, S. Dasso19;20, E. de la Fuente21, B.L. Dingus1,23 P. Desiati22, F. de O. Salles23, V. de Souza24, D. Dorner25, J. C. D´ıaz-V´elez21;22, J.A. Garc´ıa-Gonz´alez2, M. A. DuVernois22, G. Di Sciascio26, K. Engel27, H. Fleischhack10, N. Fraija28, S. Funk29, J-F. Glicenstein3, J. Gonzalez,30 M. M. Gonz´alez28, J. A. Goodman27, J. P. Harding1, A. Haungs31, J. Hinton15, B. Hona10, D. Hoyos32;33, P. Huentemeyer10, A. Iriarte34, A. Jardin-Blicq15, V. Joshi15, S. Kaufmann11, K. Kawata35, S. Kunwar15, J. Lefaucheur3, J.-P. Lenain36, K. Link31, R. L´opez-Coto37, V. Marandon15, M. Mariotti38, J. Mart´ınez-Castro39, H. Mart´ınez-Huerta24, M. Mostaf´a6, A. Nayerhoda14, L. Nellen32, E. de O~naWilhelmi40;41, R.D. Parsons15, B. Patricelli42;43, A. Pichel19, Q. Piel12, E. Prandini38, E. Pueschel41, S. Procureur3, A. Reisenegger44;45, C. Rivi`ere27, J. Rodriguez2;46, A. C. Rovero19, G. Rowell7, E. L. Ruiz-Velasco15, A. Sandoval2, M. Santander47, T. Sako35, T. K. Sako35, K. Satalecka41, H. Schoorlemmer15;?, F. Sch¨ussler3;?, M. Seglar-Arroyo3, A.
    [Show full text]
  • Open Research Online Oro.Open.Ac.Uk
    Open Research Online The Open University’s repository of research publications and other research outputs Investigating Exoplanets and Transients Using Small-Aperture Telescopes Thesis How to cite: Busuttil, Richard (2017). Investigating Exoplanets and Transients Using Small-Aperture Telescopes. PhD thesis The Open University. For guidance on citations see FAQs. c 2016 The Author Version: Version of Record Copyright and Moral Rights for the articles on this site are retained by the individual authors and/or other copyright owners. For more information on Open Research Online’s data policy on reuse of materials please consult the policies page. oro.open.ac.uk Investigating Exoplanets and Transients Using Small-Aperture Telescopes Submitted for the degree of Doctor of Philosophy in Astronomy and Astrophysics Richard Busuttil MPhys (Hons) Supervisors: Dr. Ulrich Kolb, Dr. Carole Haswell The Open University Submitted September 2016 Abstract This work characterises PIRATE’s primary camera, the SBIG STX-16803, as well as assessing the usefulness and impact of a small-aperture semi-autonomous facility in Mallorca for exoplanet studies and studies of transient sources. Additionally, a method for exploring the Roche lobe of an exoplanet and the effects this has on the shape and density of the planet is also described. PIRATE is a small aperture photometric facility that can be operated remotely or autonomously, is constructed from commercially available hardware and utilised by The Open University for research, education and outreach. The camera gain measure- ments are within the manufacturer specifications while the read noise deviates quite significantly. The camera shutter is also verified to evenly illuminate the CCD which may be suffering from a form of residual image.
    [Show full text]