DOCSLIB.ORG

Spring 2021 Newsletter

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
Spring 2021 Newsletter The Adolph C. and Mary Sprague Newsletter MILLER INSTITUTE Spring 2021 for Basic Research in Science Rewinding the Orbital Histories of INSIDE THIS EDITION Satellite Galaxies Miller Fellow Focus 1, 6, 7 Miller Fellow Focus: Ekta Patel Call for Nominations/Applications 2, 3 Miller Fellowship Awardees 4, 5 ust as the Moon orbits around the JEarth and the Earth orbits around the Next Steps 5 Sun, some galaxies also orbit around one another. My work focuses on local In the News 7 small galaxies (called satellite galaxies) Welcome & Thank You 8 orbiting around larger, more massive host galaxies. Satellite galaxies are espe- cially important because they directly shape the evolutionary pathways of Call for Nominations galaxies like our own Milky Way. Over the course of billions of years, satel- lite galaxies spiral inwards and eventu- Visiting Miller Professorship ally merge into their host galaxy, fueling Departmental Nominations their growth. As a Miller Fellow, I aim to Deadline: September 3, 2021 constrain the orbital histories of local timeline of satellite galaxies around the satellites galaxies to gain crucial insight Milky Way, highlighting that the num- Miller Research Fellowship on the interplay between satellite gal- ber of known Milky Way satellites prior Nominations axies and their host galaxies, which ulti- to the year 2000 was only about a doz- Deadline: September 10, 2021 mately helps build on our understand- en, but then doubled between 2000- ing of hierarchical galaxy formation. 2010 and doubled again between Miller Research Professorship 2010-2020! Applications ur Milky Way is just one of many Deadline: September 14, 2021 Ogalaxies in our galactic neighbor- ome of most recently discovered hood known as the Local Group. The satellite galaxies, the “ultra-faint S "The experience [as a Miller Professor] of be- Local Group also includes Andromeda, dwarf galaxies,” only have stellar masses ing amongst postdoctoral researchers, faculty our neighboring massive spiral galaxy between 100-100,000 times the mass colleagues from across campus, and visiting and the dozens of low mass satellite of the Sun and are thought to be fossils professors who are all asking and answering galaxies orbiting around both the Milky of the first galaxies to form in the Uni- fundamental questions has reminded me of the joy of pure inquiry and the excitement of pur- Way and Andromeda. In total, there verse. For comparison, the stellar mass suing the unknown, partially insulated from the are approximately 60 known satellite of the Milky Way is about ten times normal day-to-day constraints of faculty life. I galaxies of the Milky Way and nearly higher and the total mass of the Milky am grateful to the Miller Institute, the staff, and 35 known satellite galaxies around the Way, including all of the stars, gas, dust, the Miller community as a whole for the lasting impact that my Miller Professorship has had on Andromeda galaxy. However, it was and invisible dark matter amount to me and my lab.” not until very recently that most of nearly one trillion times the mass of the - Dan Fletcher these satellite galaxies were discovered. Sun. Theoretical predictions suggest Figure 1 (page 6) shows the discovery that the Milky Way could host in excess Miller Professor 2019-2020 Bioengineering, UC Berkeley Faculty Scientist, Lawrence Berkeley National Laboratory Investigator, Chan-Zuckerberg Biohub CONTINUED ON PAGE 6 > 1 miller.berkeley.edu The Adolph C. and Mary Sprague Miller Institute for Basic Research in Science Call for Visiting Miller Professor Nominations Online Nomination Deadline: September 3, 2021 Visiting Miller Research Professorship AY 2022-2023 The Advisory Board of the Miller Institute for Basic Research in Science invites Berkeley faculty to submit online departmental nominations for Visiting Miller Research Professorships and the Gabor A. and Judith K. Somorjai Visiting Miller Professorship Award for terms in Fall 2022 or Spring 2023. The purpose of these Visiting Miller Professorships is to bring promising or eminent scientists to the Berkeley campus on a short-term basis for collaborative research interactions. It is required that awardees be in residence at Berkeley during their appointment term. Faculty members or research scientists from around the world are eligible to be consid- ered for sponsorship. Non-US citizens must be eligible for J-1 Scholar visa status in order to be awarded. Faculty members at other UC campuses are eligible to be nominated for this program. The Miller Institute, as the sponsor and administrative department, will extend an invitation after advising the department of its selection. Beginning in June 2021, nominations will be accepted from UC Berkeley faculty for Visiting Professorship candidates for the 2022-2023 academic year. Nominations are judged competitively and are due by September 3, 2021. It is anticipated that be- tween four and ten awards will be made. For more information, and to access the nomination form, visit miller.berkeley.edu/visiting-professorship. Call for Miller Professor Applications Online Application Deadline: September 14, 2021 Miller Research Professorship AY 2022-2023 The Miller Professorship program is looking with a view to the future in announcing the call for applications for terms in the academic year 2022-2023. The objective of the Miller Professorship program is to provide opportunities for faculty to pursue new research directions on the Berkeley campus and to participate in the vibrant Miller Institute interdisciplinary scientific community. Appointees are encouraged to follow promising leads that may develop in the course of their research. In order to accommodate a range of fac- ulty members, the Miller Professorship program offers appointees, in consultation with their Departmental Chair, the option of taking teaching relief or continuing to teach during their Miller Professorship term. Funds will be distributed differently depending upon the choice selected. The primary evaluation criteria will continue to be research excellence. Proposals to write books are not viewed as competitive. Ap- plicants are also encouraged to describe their interest in participating in the Miller Institute community and providing mentorship to the Miller Research Fellows. Beginning in June 2021, applications will be accepted from UC Berkeley faculty for terms in the 2022-2023 academic year. Applica- tions are judged competitively and are due by September 14, 2021. It is anticipated that between four and ten awards will be made. For more information, and to access the application, visit miller.berkeley.edu/professorship. :: Nomination & Application details: miller.berkeley.edu :: Questions? [email protected] 2 miller.berkeley.edu The Adolph C. and Mary Sprague Miller Institute for Basic Research in Science Call for Nominations: Miller Research Fellowship 2022-2025 Term Nomination Deadline: September 10, 2021 he Miller Institute for Basic Research in Science invites department chairs, faculty advisors, professors and research scientists at institu- Ttions around the world to submit nominations for Miller Research Fellowships in the basic sciences. Through this program, the Miller Institute seeks to discover and encourage individuals of outstanding talent, and to provide them with the opportunity to pursue their research on the Berkeley campus. Fellows are selected on the basis of their academic achievement and the promise of their scientific re- search. Miller Fellows also have a keen curiosity about all science and share an appreciation for an interdisciplinary experience. The Miller Institute is the administrative home department for each Miller Fellow who is hosted by an academic department on the Berkeley cam- pus. A list of current and former Miller Research Fellows can be found at: https://miller.berkeley.edu/fellowship/members/all-mf-by-name. he Miller Institute also welcomes nominations for the Kathryn A. Day Miller Postdoctoral Fellowship award for the 2022-2025 Fel- Tlowship cohort. Named in honor of the Institute's retired Chief Administrative Officer Kathy Day, this award is intended for an early career scientist who, in addition to excelling in their pursuit of basic science research, also engages in outreach in support of science. iller Research Fellowships are intended for exceptional young scientists of great promise who have recently been awarded, or who Mare about to be awarded, the doctoral degree. Miller Fellows are expected to begin their Fellowship shortly after being awarded their Ph.D. A short period as a postdoctoral fellow elsewhere does not exclude eligibility, but applicants who have already completed more than two years of postdoctoral experience are not eligible for nomination. A nominee cannot hold a paid or unpaid position on the Berkeley campus at the time of nomination or throughout the competition and award cycle which may extend into February 2022. Nominees who are non-US citizens must show eligibility for obtaining J-1 Scholar visa status for the duration of the Miller Fellowship. Non-US citizens will be required to prove English language proficiency prior to award. The Miller Institute does not support H1B visa status. Eligible nominees will be invited by email by the Institute to apply for the Fellowship after the nomination has been reviewed. Direct applications and self- nominations are not accepted. All nominations must be submitted using the online nomination system at:miller.berkeley.edu/fellowship. Nominators will need the following
Load more

Recommended publications
  • Lecture 7: the Local Group and Nearby Clusters
    Lecture 7: the Local Group and nearby clusters • in this lecture we move up in scale, to explore typical clusters of galaxies – the Local Group is an example of a not very rich cluster • interesting topics include: – clusters and the structure of the Universe – the fate of galaxies: stable, destroyed or cannibals? Galaxies – AS 3011 1 the Local Group Galaxies – AS 3011 2 1 Inner Solar System Galaxies – AS 3011 3 Galaxies – AS 3011 4 2 some Local Group galaxies, roughly to the same physical scale: M31, Leo I LMC, M32 SMC MW M33 (images courtesy AAO) Galaxies – AS 3011 5 first impressions • there are some obvious properties of the Local Group: – it’s mostly empty, i.e. galaxies are quite distant from each other – with some exceptions like satellite galaxies – the three spirals are easily the biggest – dwarf galaxies are on the outskirts of the group • how typical is this of other galaxy groups? – turns out that the Local group is not very rich in galaxies Galaxies – AS 3011 6 3 groups and clusters • groups contain a smaller number of galaxies than clusters, and are more compact in both space and velocity spread: group: cluster: no. galaxies ~10+ >50 core radius ~300 kpc ~300 kpc median radius ~1 Mpc ~ 3Mpc v-dispersion 150 km/s 800 km/s M/L ~200 ~200 13 15 total mass few 10 Msolar few 10 Msolar Galaxies – AS 3011 7 classifying the Local Group • the Local Group has only about 10 significant galaxies 8 (L > 10 Lsolar), so does not qualify as a cluster – NB, dwarf spheroidals etc.
    [Show full text]
  • Introduction to Astronomy from Darkness to Blazing Glory
    Introduction to Astronomy From Darkness to Blazing Glory Published by JAS Educational Publications Copyright Pending 2010 JAS Educational Publications All rights reserved. Including the right of reproduction in whole or in part in any form. Second Edition Author: Jeffrey Wright Scott Photographs and Diagrams: Credit NASA, Jet Propulsion Laboratory, USGS, NOAA, Aames Research Center JAS Educational Publications 2601 Oakdale Road, H2 P.O. Box 197 Modesto California 95355 1-888-586-6252 Website: http://.Introastro.com Printing by Minuteman Press, Berkley, California ISBN 978-0-9827200-0-4 1 Introduction to Astronomy From Darkness to Blazing Glory The moon Titan is in the forefront with the moon Tethys behind it. These are two of many of Saturn’s moons Credit: Cassini Imaging Team, ISS, JPL, ESA, NASA 2 Introduction to Astronomy Contents in Brief Chapter 1: Astronomy Basics: Pages 1 – 6 Workbook Pages 1 - 2 Chapter 2: Time: Pages 7 - 10 Workbook Pages 3 - 4 Chapter 3: Solar System Overview: Pages 11 - 14 Workbook Pages 5 - 8 Chapter 4: Our Sun: Pages 15 - 20 Workbook Pages 9 - 16 Chapter 5: The Terrestrial Planets: Page 21 - 39 Workbook Pages 17 - 36 Mercury: Pages 22 - 23 Venus: Pages 24 - 25 Earth: Pages 25 - 34 Mars: Pages 34 - 39 Chapter 6: Outer, Dwarf and Exoplanets Pages: 41-54 Workbook Pages 37 - 48 Jupiter: Pages 41 - 42 Saturn: Pages 42 - 44 Uranus: Pages 44 - 45 Neptune: Pages 45 - 46 Dwarf Planets, Plutoids and Exoplanets: Pages 47 -54 3 Chapter 7: The Moons: Pages: 55 - 66 Workbook Pages 49 - 56 Chapter 8: Rocks and Ice:
    [Show full text]
  • 1410.0681V1.Pdf
    ACCEPTED FOR PUBLICATION IN THE ASTROPHYSICAL JOURNAL Preprint typeset using LATEX style emulateapj v. 05/12/14 THE QUENCHING OF THE ULTRA-FAINT DWARF GALAXIES IN THE REIONIZATION ERA1 THOMAS M. BROWN2, JASON TUMLINSON2, MARLA GEHA3, JOSHUA D. SIMON4,LUIS C. VARGAS3,DON A. VANDENBERG5,EVAN N. KIRBY6, JASON S. KALIRAI2,7,ROBERTO J. AVILA2, MARIO GENNARO2,HENRY C. FERGUSON2 RICARDO R. MUÑOZ8,PURAGRA GUHATHAKURTA9, AND ALVIO RENZINI10 Accepted for publication in The Astrophysical Journal ABSTRACT We present new constraints on the star formation histories of six ultra-faint dwarf galaxies: Bootes I, Canes Venatici II, Coma Berenices, Hercules, Leo IV, and Ursa Major I. Our analysis employs a combination of high-precision photometry obtained with the Advanced Camera for Surveys on the Hubble Space Telescope, medium-resolutionspectroscopy obtained with the DEep Imaging Multi-Object Spectrograph on the W.M. Keck Observatory, and updated Victoria-Regina isochrones tailored to the abundance patterns appropriate for these galaxies. The data for five of these Milky Way satellites are best fit by a star formation history where at least 75% of the stars formed by z ∼ 10 (13.3 Gyr ago). All of the galaxies are consistent with 80% of the stars forming by z ∼ 6 (12.8 Gyr ago) and 100% of the stars forming by z ∼ 3 (11.6 Gyr ago). The similarly ancient populations of these galaxies support the hypothesis that star formation in the smallest dark matter sub-halos was suppressed by a global outside influence, such as the reionization of the universe. Keywords: Local Group — galaxies: dwarf — galaxies: photometry — galaxies: evolution — galaxies: for- mation — galaxies: stellar content 1.
    [Show full text]
  • Snake in the Clouds: a New Nearby Dwarf Galaxy in the Magellanic Bridge ∗ Sergey E
    MNRAS 000, 1{21 (2018) Preprint 19 April 2018 Compiled using MNRAS LATEX style file v3.0 Snake in the Clouds: A new nearby dwarf galaxy in the Magellanic bridge ∗ Sergey E. Koposov,1;2 Matthew G. Walker,1 Vasily Belokurov,2;3 Andrew R. Casey,4;5 Alex Geringer-Sameth,y6 Dougal Mackey,7 Gary Da Costa,7 Denis Erkal8, Prashin Jethwa9, Mario Mateo,10, Edward W. Olszewski11 and John I. Bailey III12 1McWilliams Center for Cosmology, Carnegie Mellon University, 5000 Forbes Ave, 15213, USA 2Institute of Astronomy, University of Cambridge, Madingley road, CB3 0HA, UK 3Center for Computational Astrophysics, Flatiron Institute, 162 5th Avenue, New York, NY 10010, USA 4School of Physics and Astronomy, Monash University, Clayton 3800, Victoria, Australia 5Faculty of Information Technology, Monash University, Clayton 3800, Victoria, Australia 6Astrophysics Group, Physics Department, Imperial College London, Prince Consort Rd, London SW7 2AZ, UK 7Research School of Astronomy and Astrophysics, Australian National University, Canberra, ACT 2611, Australia 8Department of Physics, University of Surrey, Guildford, GU2 7XH, UK 9European Southern Observatory, Karl-Schwarzschild-Str. 2, 85748 Garching, Germany 10Department of Astronomy, University of Michigan, 311 West Hall, 1085 S University Avenue, Ann Arbor, MI 48109, USA 11Steward Observatory, The University of Arizona, 933 N. Cherry Avenue., Tucson, AZ 85721, USA 12Leiden Observatory, Leiden University, Niels Bohrweg 2, 2333 CA Leiden, The Netherlands Accepted XXX. Received YYY; in original form ZZZ ABSTRACT We report the discovery of a nearby dwarf galaxy in the constellation of Hydrus, between the Large and the Small Magellanic Clouds. Hydrus 1 is a mildy elliptical ultra-faint system with luminosity MV 4:7 and size 50 pc, located 28 kpc from the Sun and 24 kpc from the LMC.
    [Show full text]
  • Ml Driven Prediction of Collision of Milky Way & Andromeda
    International Journal of Recent Technology and Engineering (IJRTE) ISSN: 2277-3878, Volume-8 Issue-3, September 2019 Ml Driven Prediction of Collision of Milky Way & Andromeda Ansh Mittal, Anusurya, Deepika Kumar, Garima Kumar Abstract: The 3D position of Sun with respect to the galactic center of Milky Way can be used to understand its evolution. After Milky Way collides with Andromeda(M31), the same will hold true. Ensuing sections deal with the implementation of Regressive Analysis to predict the location of Sun in the galactic center after Galactic collision. This model utilizes results of previous studies of black hole mergers to predict the resultant mass of Sagittarius A* and M31’s black hole, which had been found to be (1.49±0.16) × Figure 1: Different types of Collisions between two 8 10 M☉. This mass has been used to calculate the centrifugal force galaxies as has been mentioned in [5] that Sun might experience during and after the galactic collision. The current position, inclination, and velocity of Sun (derived Galaxies may be of various types [7] like the dark galaxy, from aforementioned predictions) have been used to predict its Type CD galaxy, Type D galaxy, and Ultra Diffuse galaxy. distance and inclination after the collision which has been Out of these galaxies, UDG or the ultra-diffuse galaxy had o predicted as 63,362.83 ly and 32.75 , from the new galactic center been a galaxy which has very low luminosity. Although Milky and its plane (97.48% and 96.32% accurate) respectively. way and UDG galaxy share the same mass and size, only 1% Index Terms: Sun, Milky Way, Andromeda(M31), Regression of the visible star count has been observed there for UDG Analysis, Galactic collision, Sagittarius A*.
    [Show full text]
  • Evidence of Enrichment by Individual SN from Elemental Abundance Ratios in the Very Metal-Poor Dsph Galaxy Boötes I
    A&A 508, L1–L4 (2009) Astronomy DOI: 10.1051/0004-6361/200912833 & c ESO 2009 Astrophysics Letter to the Editor Evidence of enrichment by individual SN from elemental abundance ratios in the very metal-poor dSph galaxy Boötes I S. Feltzing1,K.Eriksson2, J. Kleyna3, and M. I. Wilkinson4 1 Lund Observatory, Box 43, 221 00 Lund, Sweden e-mail: [email protected] 2 Department of Astronomy and Space Physics, Uppsala University, Box 515, 751 20 Uppsala, Sweden e-mail: [email protected] 3 Institute for Astronomy, Honululu, 2680 Woodlawn Drive, Honolulu, HI 96822, USA 4 Department of Physics and Astronomy, University of Leicester, University Road, Leicester LE1 7RH, UK e-mail: [email protected] Received 6 July 2009 / Accepted 18 September 2009 ABSTRACT Aims. We establish the mean metallicity from high-resolution spectroscopy for the recently found dwarf spheroidal galaxy Boötes I and test whether it is a common feature for ultra-faint dwarf spheroidal galaxies to show signs of inhomogeneous chemical evolution (e.g. as found in the Hercules dwarf spheroidal galaxy). Methods. We analyse high-resolution, moderate signal-to-noise spectra for seven red giant stars in the Boötes I dSph galaxy using standard abundance analysis techniques. In particular, we assume local thermodynamic equilibrium and employ spherical model atmospheres and codes that take the sphericity of the star into account when calculating the elemental abundances. Results. We confirm previous determinations of the mean metallicity of the Boötes I dwarf spheroidal galaxy to be −2.3 dex. Whilst five stars are clustered around this metallicity, one is significantly more metal-poor, at −2.9 dex, and one is more metal-rich at, −1.9 dex.
    [Show full text]
  • Never-Before-Seen Radio Waves Detected from Nearby Stars and Distant Galaxies 19 August 2021
    Never-before-seen radio waves detected from nearby stars and distant galaxies 19 August 2021 The researchers not only took the sharpest radio images of the Cloud ever recorded, but during their analysis they also studied the stars themselves which form the cloud's structure, including the Tarantula Nebula, the most active star-formation region in the Local Group. Furthermore, newly detected radio emission has also been studied from distant galaxies in the background as well as stars in the foreground from our own Milky Way. This study, published in Monthly Notices of the Royal Astronomical Society, forms part of the Evolutionary Map of the Universe (EMU) Early Science Project, which will observe the entire Southern sky and is predicted to detect around 40 Credit: Keele University million galaxies. The data will ultimately be used to give researchers a clearer picture of how galaxies, and their stars, have evolved throughout time. Scientists have measured thousands of nearby Lead author Clara Pennock from Keele University stars and far away galaxies that have never been said: "The sharp and sensitive new image reveals identified before at radio wavelengths, while thousands of radio sources we've never seen studying a galactic body that neighbors our own before. Most of these are actually galaxies millions Milky Way galaxy—the Large Magellanic Cloud. or even billions of light years beyond the Large Magellanic Cloud. We typically see them because Led by Keele University Ph.D. student Clara M. of the supermassive black holes in their centers Pennock and Reader in Astrophysics, Dr. Jacco which can be detected at all wavelengths, van Loon, the international team of researchers especially radio.
    [Show full text]
  • Mapping the Youngest and Most Massive Stars in the Tarantula Nebula with MUSE-NFM
    Astronomical Science DOI: 10.18727/0722-6691/5223 Mapping the Youngest and Most Massive Stars in the Tarantula Nebula with MUSE-NFM Norberto Castro 1 Myrs, but in very dramatic ways. The are to unveil the nature of the most mas- Martin M. Roth 1 energy released during their short lives, sive stars, to constrain the role of these Peter M. Weilbacher 1 and their deaths in supernova explosions, parameters in their evolution, and to pro- Genoveva Micheva 1 shape the chemistry and dynamics of vide homogeneous results and landmarks Ana Monreal-Ibero 2, 3 their host galaxies. Ever since the reioni- for the theory. Spectroscopic surveys Andreas Kelz1 sation of the Universe, massive stars have transformed the field in this direc- Sebastian Kamann4 have been significant sources of ionisa- tion, yielding large samples for detailed Michael V. Maseda 5 tion. Nonetheless, the evolution of mas- quantitative studies in the Milky Way (for Martin Wendt 6 sive O- and B-type stars is far from being example, Simón-Díaz et al., 2017) and in and the MUSE collaboration well understood, a lack of knowledge that the nearby Magellanic Clouds (for exam- is even worse for the most massive stars ple, Evans et al., 2011). However, massive (Langer, 2012). These missing pieces in stars are rarer than smaller stars, and 1 Leibniz-Institut für Astrophysik Potsdam, our understanding of the formation and very massive stars (> 70 M☉) are even Germany evolution of massive stars propagate to rarer. The empirical distribution of stars 2 Instituto de Astrofísica de Canarias, other fields in astrophysics.
    [Show full text]
  • The Tarantula Nebula As a Template for Extragalactic Star Forming Regions from VLT/MUSE and HST/STIS
    This is a repository copy of The Tarantula Nebula as a template for extragalactic star forming regions from VLT/MUSE and HST/STIS. White Rose Research Online URL for this paper: http://eprints.whiterose.ac.uk/112327/ Version: Accepted Version Proceedings Paper: Crowther, P.A., Caballero-Nieves, S.M., Castro, N. et al. (1 more author) (2016) The Tarantula Nebula as a template for extragalactic star forming regions from VLT/MUSE and HST/STIS. In: Proceedings of the International Astronomical Union. IAUS 329: The Lives and Death-Throes of Massive Stars, 28 Nov - 02 Dec 2016, Auckland, New Zealand. Cambridge University Press , pp. 292-296. https://doi.org/10.1017/S1743921317002484 Reuse Unless indicated otherwise, fulltext items are protected by copyright with all rights reserved. The copyright exception in section 29 of the Copyright, Designs and Patents Act 1988 allows the making of a single copy solely for the purpose of non-commercial research or private study within the limits of fair dealing. The publisher or other rights-holder may allow further reproduction and re-use of this version - refer to the White Rose Research Online record for this item. Where records identify the publisher as the copyright holder, users can verify any specific terms of use on the publisher’s website. Takedown If you consider content in White Rose Research Online to be in breach of UK law, please notify us by emailing [email protected] including the URL of the record and the reason for the withdrawal request. [email protected] https://eprints.whiterose.ac.uk/ The lives and death-throes of massive stars Proceedings IAU Symposium No.
    [Show full text]
  • Draft181 182Chapter 10
    Chapter 10 Formation and evolution of the Local Group 480 Myr <t< 13.7 Gyr; 10 >z> 0; 30 K > T > 2.725 K The fact that the [G]alactic system is a member of a group is a very fortunate accident. Edwin Hubble, The Realm of the Nebulae Summary: The Local Group (LG) is the group of galaxies gravitationally associ- ated with the Galaxy and M 31. Galaxies within the LG have overcome the general expansion of the universe. There are approximately 75 galaxies in the LG within a 12 diameter of ∼3 Mpc having a total mass of 2-5 × 10 M⊙. A strong morphology- density relation exists in which gas-poor dwarf spheroidals (dSphs) are preferentially found closer to the Galaxy/M 31 than gas-rich dwarf irregulars (dIrrs). This is often promoted as evidence of environmental processes due to the massive Galaxy and M 31 driving the evolutionary change between dwarf galaxy types. High Veloc- ity Clouds (HVCs) are likely to be either remnant gas left over from the formation of the Galaxy, or associated with other galaxies that have been tidally disturbed by the Galaxy. Our Galaxy halo is about 12 Gyr old. A thin disk with ongoing star formation and older thick disk built by z ≥ 2 minor mergers exist. The Galaxy and M 31 will merge in 5.9 Gyr and ultimately resemble an elliptical galaxy. The LG has −1 vLG = 627 ± 22 km s with respect to the CMB. About 44% of the LG motion is due to the infall into the region of the Great Attractor, and the remaining amount of motion is due to more distant overdensities between 130 and 180 h−1 Mpc, primarily the Shapley supercluster.
    [Show full text]
  • On the Collision Between the Milky Way and the Andromeda Galaxy Master Thesis, Astronomy and Astrophysics
    On the collision between the Milky Way and the Andromeda Galaxy Master thesis, astronomy and astrophysics J.C.J.G. Withagen Supervisors: dr. S. Portegies Zwart and dr. S. Harfst Sterrenkundig Instituut \Anton Pannekoek" Universiteit van Amsterdam Abstract This paper argues, that using a recent estimated transverse velocity component of Andromeda of vtrans = 42 km/s, it will influence the time of merger between the to systems considerably. We present several models of the Local Group, using models which are derived from distribu- tion functions of actual galaxies and evaluate them using N-body simulations. We preformed our simulations using Graphic Processing Cards. We find that the two galaxies are not likely to collide in at least 9 Gyr and will not form the elliptical galaxy Milkomeda. We present evidence that this time of merger could be much longer then 9 Gyr, Most likely in the order of two Hubble times. We also preformed a parameter study, varying vtrans, the total mass and the extent of Andromeda's halo, which resulted in constructing a parameter space we can use to test models with different total masses. Subject heading: dark matter - galaxies: individual (M31) Galaxy: general - Local Group - methods: N-body simulations i Preface This thesis covers the work done during my masters project as part of the fulfillment of the Masters degree in astronomy and astrophysics at the University of Amsterdam. This research project was done under the supervision of dr. S Portegies Zwart and dr. S Harfst at the astronomical institute "Anton Pannekoek" form September 2007 until August 2008.
    [Show full text]
  • The Dynamics of the Galaxies in the Local Group Roeland Van Der Marel (Stsci)
    The Dynamics of the Galaxies in the Local Group Roeland van der Marel (STScI) Main collaborators: Jay Anderson, Gurtina Besla, Nitya Kallivayalil, Tony Sohn 2 [R. Powell] 3 [R. Powell] 4 Why Study the Local Group? • Nearest opportunity for study of fossil record of hierarchical structure formation in the Universe – Best spatial resolution • Many observational surveys – 2MASS/DENIS, SDSS, RAVE, GAIA, wide-field ground-based programs, etc. • Many recent insights – Continuous discovery of new dwarf galaxies, tidal streams, etc. • Structure, Dynamics and Populations of Galaxies ⇒ Formation and Evolution of Galaxies 5 Orbits: proper motions ⇒ Mass, History, Future Milky Way M31 SagDIG Tucana SMC Magellanic MW Stream satellites LMC M33 M31 satellites [Grebel 2000] 6 Proper Motion Measurement • Relevant proper motions are small • For 0.05” pixel size, 0.01 pixel in 5 years corresponds to 100 micro-arcsec/yr, which is – 3 km/s at 6.4 kpc – 30 km/s at 64 kpc – 300 km/s at 640 kpc • Space observations generally required: – HST: can do this now! – GAIA (2013-2018): bright stars in uncrowded regions – SIM: discontinued 7 HST proper motions • Essential properties: – Long-term stability – High spatial resolution – High S/N on faint sources (collecting area +low background) • Required tools (Jay Anderson): – Accurate geometric distortion calibrations – Accurate PSF models that allow for PSF variability – Software to fit PSFs optimized for astrometry – Understanding or correction for Charge Transfer Efficiency • Observational design: – Sub-pixel dithering
    [Show full text]