DOCSLIB.ORG

The Golden Mass of Galaxies and Black Holes with Deep Learning Avishai Dekel the Hebrew University of Jerusalem & UCSC

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
The Golden Mass of Galaxies and Black Holes with Deep Learning Avishai Dekel the Hebrew University of Jerusalem & UCSC The Golden Mass of Galaxies and Black Holes with Deep Learning Avishai Dekel The Hebrew University of Jerusalem & UCSC Ofer Lahav’s 60 th Birthday, April 2019 A Characteristic Mass for Galaxy Formation Efficiency Black Holes of galaxy formation low-mass high-mass quenching quenching Behroozi+ 2013 A Characteristic TimeMass for Galaxy Formation Star-formation density high-mass low-mass quenching quenching typical halos at z~2 11-12 are ~10 M AGN Activation at the Critical Mass Forster-Schreiber+18 KMOS 3D z=0.6-2.7 599 galaxies Why do galaxies like to form at the golden mass (and time)? Why do black holes grow rapidly once their host galaxies are above the golden mass? A Characteristic Mass for Galaxy Formation 10.5 12 Mstar ~10 M Mvir ~10 M Vvir ~100 km/s - Hot halo (virial shock heating) at M>M crit Rees & Ostriker 77, Silk 77, Binney 77, Dekel & Birnboim 06 - Supernova feedback efficient at M<M crit (V crit ) Larson 74 , Dekel & Silk 86 -> Compaction to Blue Nuggets + quenching at ~M crit (any z) Zolotov+15, Tacchella+16, Dekel+17 -> Black Holes suppressed by supernovae at M<M crit , Black hole growth at M>M crit -> Quenching of star formation at M>M crit triggered by compaction, maintained by hot halo & black hole 2. Virial Shock Heating in Massive Halos Dekel & Birnboim 06, Rees & Ostriker 77, Silk 77, Binney 77 Hot Halo Scale: shutdown of cold gas supply Dekel & Birnboim 06, Rees & Ostriker 77, Silk 77, Binney 77 11.8 critical halo mass ~~10 Mʘ −1 < −1 tcool tcompress slow cooling -> shock log T Kravtsov+ 11.5-12 Mcrit by Shock Heating: M vir ~10 M 10 13 Simulations: Ocvirk, Pichon, Teyssier 08; Dekel+ 09 hot CGM hot CGM 12 cold streams 10 Dekel & shock heating Birnboim 06 Mvir [M ʘ] cold CGM 10 11 typical halos Press & Schechter 74 0 1 2 3 4 5 redshift z Empirical Model From Observations Behroozi+ Fraction of star-forming galaxies 3. Supernova Feedback in Low-mass Halos Larson 74, Dekel & Silk 86 Supernova Fdbk Scale V vir ~100 km/s Dekel & Silk 86 Energy fed to the ISM by supernova bubble before fading: ≈ 2 ≈ ESN M ∗VSN , VSN 120 km/s Gas binding energy: ≈ 2 2 = Egas M gas Vvir , Vvir GM / R ESN ~ E gas & star formation at peak efficiency M *~M gas --> an upper limit for efficient supernova feedback: ≈ → ≈ × 11 = Vvir, SN 120 km/s M vir, SN 7 10 M ⊗ at( z )0 11.5-12 Mcrit by SN Feedback: M vir ~10 M 10 13 hot CGM hot CGM 12 cold streams 10 Dekel & shock heating Birnboim 06 Mvir [M ʘ] cold CGM 10 11 Dekel & Silk 86 typical halos Press & Schechter 74 0 1 2 3 4 5 redshift z 4. Wet Compaction to Blue Nuggets Dekel & Burkert 14, Zolotov+15, Tacchella+16a,b, Dekel, Lapiner+18 Red Nugget Blue Nugget gas + young stars wet compaction max density core: blue nugget vdi disk core depletion: a hole and a ring vela v 2 07 stars wet compaction max density core: blue nugget green nugget red nugget + envelope vela v 2 07 Compaction -> quenching in the inner 1 kpc stars 10 1 kpc dark matter M gas 8 diffuse compaction quenching 2 star-formation rate M 0 time Compaction and Quenching in Simulations diffuse star forming blue nugget L-shape track quenched red nugget Zolotov+15 Tacchella+16 Dekel+17 diffuse compact Observed L-Shape Track Barro+17 BN compaction star forming quenching quenched diffuse compact Blue Nugget --> Red Nugget gas stars gas stars blue nugget red nugget dense gas core -> dense stellar core gas depletion from core, gas ring may form, -> inside-out quenching stellar core remains dense from BN to RN What is the Trigger of wet Compaction? Drastic loss of angular momentum - Mergers (major, minor) (Barnes, Hernquist 91; Hopkins+ 06) - VDI-driven inflow (Dekel, Burkert 15) - Counter-rotating streams (Danovich+ 15) - Tidal compression (Dekel+ 03; Renaud+ 14; Mandelker+ 16) - Triaxial halo core (Ceverino+ 15; Tomassetti+ 16) - Return of recycled low-AM gas (Elmegreen+ 14; DeGraf+ 16) Counter-rotating Streams Danovich+15 Rv 1/3 streams are counter-rotating A Critical Mass for Blue Nuggets (at all z) 10 11.5 Mstar ~10 M Mvir ~10 M Hot CGM SN fdbk Origin of BN scale? SN fdbk + hot CGM time Deep Learning: BNs inTheory vs Observations Huertas-Company+ 18 Pre BN Blue Nugget Post BN Identify BNs in 3D simulations (gas, stars) Train CNN on mock images of simulations Classify BNs in HST images Blue Nuggets at a Golden Mass in CANDELS Deep Learning: Huertas-Company+ 18 Luminosity (mass) eliminated Convoluted Neural Network Transition in Galaxy Properties at the BN - Diffuse -> compact core + extended disk - Star forming -> quenched - Oscillations across the Main Sequence -> quenching - Dark-matter -> baryon dominated core - Prolate -> oblate stellar system - V/ σ~1 -> V/ σ~4, dispersion -> rotation dominated -… 4. Compaction and Black-Hole Growth Dekel, Lapiner, Dubois+ 2017 Interplay between SNe and BHs RAMSES Simulation SN+BH by Dubois+ 15 z=3.60 z=3.44 no SN merger with SN merger compaction time - M<M crit : strong SN fdbk suppresses BH growth - Compaction overcomes SNe -> rapid BH growth - M>M crit : AGN fdbk helps quenching Compaction -> BH Growth stars 10 1 kpc dark matter M gas 8 black hole 2 star-formation rate M 0 diffuse compaction quenching time Compaction driving BH Growth New Horizon simulations SN+BH Dubois+ Lapiner+ stars stars 1kpc 4 compaction BH x10 DM 1kpc gas 1kpc BH growth gravity rBH Compaction driving BH Growth New Horizon simulations SN+BH Dubois+ Lapiner+ stars stars stars 1kpc BH x10 4 BH x10 4 stars 1kpc compaction compaction gas 1kpc BH growth BH growth gas 1kpc 5 BH Below the Linear Relation for M BH ~10 M New Horizon Simulation Lapiner+ Blue Nugget Magic Mass for BH is Robust in Simulations EAGLE Illustris TNG Bower+ 16 Habouzit+18 no SN w SN FIRE Angeles-Alcazar+17 11.5-12 BH Growth by Compaction at M vir ~10 M - Mvir < M crit , pre-compaction SN phase : Vesc < 100 km/s -> SN winds of 100 km/s evacuate the core -> BH growth is suppressed , Blue-Nugget formation is suppressed - Mvir ~ M crit , compaction overcoming SN fdbk : The compressed gas activates rapid BH growth - Mvir > M crit , post-compaction hot CGM phase : Vesc > 100 km/s -> SN winds are bound (by halo potential and hot gas) -> gas falls back in -> BH growth continues -> AGN self-regulates with the accretion, AGN fdbk keeps the CGM hot and suppresses SFR long term Observed High Fraction of AGN in BN Phase Kocevski+17 SFR RN diffuse BN comactness s -> Compaction triggers BH growth and AGN -> quenching AGN Activation at the Critical Mass Forster-Schreiber+18 KMOS 3D z=0.6-2.7 599 galaxies Fraction of AGN dM/dt L 2 L = 0.1 dM bh /dt c simulations BH accretion rate L=10 42.5 KMOS 3D New Horizon sims AGN Correlate with Compactness Forster-Schreuer+18 KMOS 3D z=0.6-2.7 599 galaxies M*=10.75-11.3 M*=10-10.75 incidence incidence A Characteristic Mass for Galaxy Formation 10.5 12 Mstar ~10 M Mvir ~10 M Vvir ~100 km/s - Hot halo (virial shock heating) at M>M crit Rees & Ostriker 77, Silk 77, Binney 77, Dekel & Birnboim 06 - Supernova feedback efficient at M<M crit (V crit ) Larson 74 , Dekel & Silk 86 -> Compaction to Blue Nuggets + quenching at ~M crit (any z) Zolotov+15, Tacchella+16, Dekel+17 -> Black Holes suppressed by supernovae at M<M crit , Black hole growth at M>M crit -> Quenching of star formation at M>M crit triggered by compaction, maintained by hot halo & black hole Conclusions 10 The golden mass M*~10 M (and z~2) is due to suppression of SFR by SN fdbk at low masses and CGM heating at high masses (+AGN) Wet compaction to a Blue Nugget is a dramatic event in the history of many galaxies (~40% by mergers, 30% counter-rotating streams) The major compaction is typically at the golden mass, when SN fdbk becomes ineffective and cold streams penetrate the hot CGM The Blue Nugget marks transitions in most galaxy properties: mass, size, SFR, gas fraction, metallicity, dust, dark-matter dominance, shape, kinematics, … BH growth is suppressed by SN feedback in M<M crit halos, and is triggered by Wet compaction in M>M crit halos, where SNe are ineffective & the CGM is shock heated. The resulting AGN helps maintaining the quenching Deep Learning is a tool for confronting simulations with observations 11.5-12 The Golden Mass M vir ~10 M 10 13 hot CGM SF quenching hot CGM 12 BH growth cold streams 10 Dekel & shock heating Birnboim 06 Mvir [M ʘ] 10 11 Dekel & Silk 86 SN-suppressed SF SN-suppressed BH typical halos Press & Schechter 74 0 1 2 3 4 5 redshift z Cosmic Velocity Fields, 9th IAP Colloquium, 1993 .
Load more

Recommended publications
  • Primack-Phys205-Feb2
    Physics 205 6 February 2017 Comparing Observed Galaxies with Simulations Joel R. Primack UCSC Hubble Space Telescope Ultra Deep Field - ACS This picture is beautiful but misleading, since it only shows about 0.5% of the cosmic density. The other 99.5% of the universe is invisible. Matter and Energy Content of the Universe Imagine that the entire universe is an ocean of dark energy. On that ocean sail billions of ghostly ships made of dark matter... Matter and Energy Content of the Dark Universe Matter Ships on a ΛCDM Dark Double Energy Dark Ocean Imagine that the entire universe is an ocean of dark Theory energy. On that ocean sail billions of ghostly ships made of dark matter... Matter Distribution Agrees with Double Dark Theory! Planck Collaboration: Cosmological parameters PlanckPlanck Collaboration: Collaboration: The ThePlanckPlanckmissionmission Planck Collaboration: The Planck mission 6000 6000 Angular scale 5000 90◦ 500018◦ 1◦ 0.2◦ 0.1◦ 0.07◦ Planck Collaboration: The Planck mission European 6000 ] 4000 2 ] 4000 2 K Double K µ [ µ 3000 [ 3000Dark TT Space TT 5000 D D 2000 2000Theory Agency 1000 1000 ] 4000 2 Cosmic 0 K 0 PLANCK 600 Variance600 60 µ 60 [ 3000 300300 30 TT 30 TT 0 0 Satellite D 0 0 D ∆ D Fig. 7. Maximum posterior CMB intensity map at 50 resolution derived from the joint baseline-30 analysis of Planck, WMAP, and ∆ -300 -300 408 MHz observations. A small strip of the Galactic plane, 1.6 % of the sky, is filled in by-30 a constrained realization that has the same statistical properties as the rest of the sky.
    [Show full text]
  • A Model for Core Formation in Dark Matter Haloes and Ultra-Diffuse Galaxies by Outflow Episodes
    MNRAS 491, 4523–4542 (2020) doi:10.1093/mnras/stz3306 Advance Access publication 2019 November 26 A model for core formation in dark matter haloes and ultra-diffuse galaxies by outflow episodes Jonathan Freundlich ,1‹ Avishai Dekel,1,2 Fangzhou Jiang ,1 Guy Ishai,1 Nicolas Cornuault,1 Sharon Lapiner,1 Aaron A. Dutton 3 and Andrea V. Maccio` 3,4 1Centre for Astrophysics and Planetary Science, Racah Institute of Physics, The Hebrew University, Jerusalem 91904, Israel 2Santa Cruz Institute for Particle Physics, University of California, Santa Cruz, CA 95064, USA 3New York University Abu Dhabi, PO Box 129188, Saadiyat Island, Abu Dhabi, United Arab Emirates 4 Max Planck Institute fur¨ Astronomie, Konigstuhl¨ 17, D-69117 Heidelberg, Germany Downloaded from https://academic.oup.com/mnras/article/491/3/4523/5643939 by guest on 24 September 2021 Accepted 2019 November 20. Received 2019 November 20; in original form 2019 July 26 ABSTRACT We present a simple model for the response of a dissipationless spherical system to an instantaneous mass change at its centre, describing the formation of flat cores in dark matter haloes and ultra-diffuse galaxies (UDGs) from feedback-driven outflow episodes in a specific mass range. This model generalizes an earlier simplified analysis of an isolated shell into a system with continuous density, velocity, and potential profiles. The response is divided into an instantaneous change of potential at constant velocities due to a given mass-loss or mass- gain, followed by energy-conserving relaxation to a new Jeans equilibrium. The halo profile is modelled by a two-parameter function with a variable inner slope and an analytic potential profile, which enables determining the associated kinetic energy at equilibrium.
    [Show full text]
  • Recent Astronomical Discoveries
    From the Atom to the Universe: Recent Astronomical Discoveries Jeremiah P. Ostriker Astronomy starts at the point to which chemistry has brought us: atoms. The basic stuff of which the planets and stars are made is the same as the terres- trial material discussed and analyzed in the ½rst set of essays in this volume. These are the chemical ele - ments, from hydrogen to uranium. Hydrogen, found with oxygen in our plentiful oceanic water, is by far the most abundant element in the universe; iron is the most common of the heavier elements. All the combinations of atoms in the complex chem ical com - pounds studied by chemists on Earth are also pos- sible components of the objects that we see in the cos mos. Although almost all of the regions that we astronomers study are so hot that the more com pli - JEREMIAH P. OSTRIKER, a Fellow cated compounds would be torn apart by the heat, of the American Academy since some surprisingly unstable organic molecules, such as 1975, is the Charles A. Young Pro - cyanopolyynes, have been detected in cold re gions of fes sor Emeritus of Astrophysics at space with very low density of matter. Nev ertheless, Prince ton University and Professor the astronomical world is simpler than the chemical of As tronomy at Columbia Univer - world of the laboratory or the real bio log ical world. sity. His research interests concern dark matter and dark energy, gal - But the enormous spatial and temporal extent of axy formation, and quasars. His the cosmos allows us–and in fact forces us–to ask publications include Heart of Dark - questions that would seem offbeat to a chemist.
    [Show full text]
  • Joel R. Primack, Distinguished Professor of Physics Emeritus, UCSC
    Joel R. Primack, Distinguished Professor of Physics Emeritus, UCSC Research accomplishments: I think of myself as a theoretical physicist with broad interests. My Princeton senior thesis under Gerald E. Brown's supervision was the first modern theory of nuclear fission (Primack, PRL 1966). Although it overturned the liquid drop model of Niels Bohr and John Wheeler (1939), Wheeler gave it highest marks and I graduated as the valedictorian of my class. As an undergraduate I also published papers on plasma fluid dynamics, based on research as a summer employee at Jet Propulsion Lab. I worked on theoretical particle physics as Sid Drell’s grad student at the Stanford Linear Accelerator Center (SLAC) 1966-70, as a Junior Fellow of the Harvard Society of Fellows 1970-73, and in my first decade at UCSC (1973-1983). Drell suggested that I figure out what was wrong with the apparent failure of the Drell-Hearn sum rule applied to nuclei, so Stan Brodsky I wrote fundamental papers (1968-69) on how to treat the electromagnetic interactions of composite systems such as nuclei. Tom Appelquist and I studied form factors in field theory (1970-72). Appelquist, Helen Quinn, and I wrote some of the first papers on the SU(2)xU(1) electroweak theory (1972-73). With Ben Lee and Sam Trieman I did the first calculation of the mass of the charmed quark (1973), and Abraham Pais and I (1973) showed that CP violation arises in the cross term between first and second order perturbation theory. Sam Berman and I (1974) showed that polarized electron scattering allows a high-precision test of SU(2)xU(1), which resulted in the SLAC experiment whose success helped justify the Nobel Prize for Glashow, Salam, and Weinberg.
    [Show full text]
  • Public Outreach Via Cosmological Simulation Visualizations Table Of
    Public Outreach via Cosmological Simulation Visualizations Table of Contents Page 1 1. Scientific/Technical/Management: Introduction 3 2. Key Visualization Projects 4 2.1 Bolshoi Simulation 4 Visualizing the Bolshoi Simulation 4 Bolshoi Semi-Analytic Models 4 2.2 Local Universe Simulations 5 Future of the Local Universe 6 How Structures Form in the Expanding Universe 6 2.3. High Resolution Hydrodynamic Simulations of Galaxy Formation 6 Galaxy Merger Simulations 7 Very High Resolution Simulations of Forming Galaxies 8 2.4 Additional Visualization Projects 8 Evolution and Substructure of a Milky Way Size Dark Matter Halo 8 Massive Star Formation 9 2.5 Spinoffs 9 Education Resources 9 Cold Dark Matter Explorers Computer Interactive 9 3. Role of Planetariums 9 3.1 Why Planetariums? 10 3.2 Roles of Adler and Morrison Planetariums 10 3.3 Making Visualizations 11 Real-Time vs. Pre-Rendered shows 11 3.4 Plans and Methodology for Evaluation of Visualizations 12 3.5 Dissemination 12 4. Management Plan, Division of Labor, Timeline, and Advisory Committee 12 Management 13 Staff 13 Evaluator 13 Advisory Committee 13 Capabilities of Digital Planetarium Systems 14 5. Responsiveness to NASA’s Education and Public Outreach Goals 15 Customer Needs Focus 16 6. References 18 7. CVs and Current and Pending Support 18 PI: Joel Primack – CV 20 PI: Joel Primack – Current and Pending Support 21 Co-Is: Lucy Fortson, Mark SubbaRao, and Ryan Wyatt 24 Staff: Nina McCurdy and Michelle Nichols 26 8. Budget Justification: Budget Narrative and Budget Details 31 Adler Planetarium Subcontract 32 Morrison Planetarium, California Academy of Sciences Subcontract Public Outreach via Cosmological Simulation Visualizations PI: Joel Primack, UCSC; Co-Is: Mark SubbaRao and Lucy Fortson, Adler Planetarium, and Ryan Wyatt, Morrison Planetarium; Collaborators: Michael Busha, T.
    [Show full text]
  • JOEL R. PRIMACK Physics Department, University of California, Santa Cruz, CA 95064
    JOEL R. PRIMACK Physics Department, University of California, Santa Cruz, CA 95064 EDUCATION A.B. Physics, Princeton University, 1966 (Summa cum Laude) Ph.D. Physics, Stanford University, 1970 PROFESSIONAL EXPERIENCE 1983-now Professor of Physics, UC Santa Cruz, ≥ 2007 Distinguished Prof, ≥ 2014 Emeritus 1977-1983 Associate Professor of Physics, University of California, Santa Cruz 1973-1977 Assistant Professor of Physics, University of California, Santa Cruz 1970-1973 Junior Fellow of the Society of Fellows of Harvard University HONORS AND AWARDS (partial list) A. P. Sloan Foundation Research Fellowship, 1974-1978 APS Forum on Physics and Society Award, 1977; Fellow, 1988; Leo Szilard Award, 2016 American Association for the Advancement of Science, Fellow, 1995 Humboldt Research Award of the Alexander von Humboldt Foundation, 1999-2004 SELECTED PAPERS (h-index = 70) Is Main Sequence Galaxy Star Formation Controlled by Halo Mass Accretion? By A. Rodriguez- Puebla, J. R. Primack, P. Behroozi, S. M. Faber, MNRAS, (2016). Formation of Elongated Galaxies with Low Masses at High Redshift, by Daniel Ceverino, Joel Primack, Avishai Dekel, MNRAS, 453, 408 (2015) Understanding the Structural Scaling Relations of Early-Type Galaxies, by L. A. Porter, R. S. Somerville, J. R. Primack, P. H. Johansson, MNRAS, 444, 1389 (2014) Gravitationally Consistent Halo Catalogs and Merger Trees for Precision Cosmology, by P. Behroozi, R. Wechsler, H. Wu, M. Busha, A. Klypin, J. Primack, ApJ, 763, 18 (2013) Triumphs and Tribulations of ΛCDM, by Joel R. Primack, Ann. Phys., 524, 535 (2012) Dark Matter Halos in the Standard Cosmological Model: Results from the Bolshoi Simulation, by A. A. Klypin, S.
    [Show full text]
  • Joel R. Primack
    Joel R. Primack Distinguished Professor of Physics Emeritus, University of California, Santa Cruz Office Phone: (831) 459-2580, Fax: -3043; Cell: 831 345-8960; Email: [email protected] Education: Princeton University A.B. 1966 Physics (Summa cum Laude, Valedictorian); Stanford University PhD 1970 Physics Academic Positions: Junior Fellow, Society of Fellows, Harvard University 1970-73. Assistant Professor of Physics, UCSC 1973-1977; Associate Professor of Physics, UCSC, 1977-1983; Professor of Physics, UCSC 1983- present; Distinguished Professor 2007-; Emeritus 2014-. Chair, UCSC Committee on Educational Policy, 1992-94; Chair, UCSC Committee on Computing and Telecommunications, 2008- 2011; Chair, University Committee on Computing and Communications, 2010-12; Director, University of California systemwide High-Performance Astro-Computing Center (UC-HiPACC), 2010-2015, including organizing annual AstroComputing Summer Schools Advice (partial list): SAGENAP advisory panel to DOE/NSF 2000-2001; NSF Astronomy Theory Review Panel 2000; DOE Lehman Review of SNAP Proposal 2001; Chair, NASA Cosmology panel on LTSA and ADP 2001; Cosmology Panel, Hubble Space Telescope Time Allocation Committee 2003, 2017; Editorial Board, Journal of Cosmology and Astroparticle Physics 2003-06; National Academy Beyond Einstein panel, 2006-07; National Academy Review of NASA Technology Roadmap, 2010-11 American Physical Society activities (partial list): Executive Committee, APS Division of Astrophysics, 2000-2002; APS Panel on Public Affairs (POPA) 2002-2004; Chair, POPA Task Force on Moon-Mars Program and Funding for Astrophysics 2004; Chair, APS Forum on Physics and Society 2005; Chair, APS Sakharov Prize committee 2009; Chair-Elect, APS Forum on Physics and Society, 2017-18, Chair 2019 Outreach (partial list): Smithsonian National Air and Space Museum, Advisory Committee on Cosmic Voyage IMAX film, 1994-1996.
    [Show full text]
  • Curriculum Vitae [PDF]
    Savvas M. Koushiappas Title: Associate Professor of Physics Contact Information Phone: +1-401-863-6816 Department of Physics Fax: +1-401-863-2024 Brown University, Box 1843 Email: [email protected] Providence, RI 02912 Education Ph.D. Physics, The Ohio State University, Columbus, OH, USA, 2004 Advisor: Terry P. Walker B.S. Astrophysics, The University of New Mexico, Albuquerque, NM, USA, 1998 Professional Appointments Associate Professor of Physics 7/2015{ Present Department of Physics, Brown University Providence, RI, USA Visiting Professor 5/2017 - 8/2017 Institute for Computational Science, University of Z¨urich Z¨urich, Switzerland Visiting Professor 9/2016{ 4/2017 Institute for Theory and Computation, Harvard University Cambridge, MA, USA Assistant Professor of Physics 7/2008{6/2015 Department of Physics, Brown University Providence, RI, USA Postdoctoral Researcher 10/2005{6/2008 Theoretical Division, Los Alamos National Laboratory Los Alamos, NM, USA Postdoctoral Researcher 10/2004{9/2005 ETH-Z¨urich (Swiss Federal Institute of Technology) Z¨urich, Switzerland Research interests: My research is in the interface between cosmology, particle physics and astrophysics with contribu- tions in the interconnection that exists between these disciplines. I work predominantly in the area of dark matter physics and the search for the nature of the dark matter particle. I am interested in the effects of dark matter mass and couplings to the large-scale structure of the universe, the im- plications of cosmic variance on cosmological constraints and the disentanglement of backgrounds, as well as new statistical approaches to a wide variety of problems. I also maintain interests in high-energy astrophysics, gravitational lensing and more recently in gravitational waves and how merger events can be used to explore a variety of open questions in cosmology and galaxy formation.
    [Show full text]
  • Dark Energy Physicsworld.Com Dark Energy: How the Paradigm Shifted
    Feature: The paradigm shift to dark energy physicsworld.com Dark energy: how the paradigm shifted The idea that our universe is dominated by mysterious dark energy was revealed by two paradigm- shifting studies of supernovae published in 1998. Lucy Calder and Ofer Lahav explain how the concept had in fact been brewing for at least a decade before – and speculate on where the next leap in our understanding might lie Lucy Calder has an Arguably the greatest mystery facing humanity today gravity, because he believed the universe to be static MSc in astrophysics is the prospect that 75% of the universe is made up of and eternal. He considered it a property of space itself, from University a substance known as “dark energy”, about which we but it can also be interpreted as a form of energy that College London and have almost no knowledge at all. Since a further 21% uniformly fills all of space; if Λ is greater than zero, the is currently a of the universe is made from invisible “dark matter” uniform energy has negative pressure and creates a freelance writer in that can only be detected through its gravitational bizarre, repulsive form of gravity. However, Einstein London, UK. Ofer Lahav is effects, the ordinary matter and energy making up the grew disillusioned with the term and finally abandoned Perren Professor of Earth, planets and stars is apparently only a tiny part it in 1931 after Edwin Hubble and Milton Humason Astronomy and head of what exists. These discoveries require a shift in our discovered that the universe is expanding.
    [Show full text]
  • Massive Black Hole Seeds from Low Angular Momentum Material
    Mon. Not. R. Astron. Soc. 000, 1–15 (2003) Printed 25 October 2018 (MN LATEX style file v2.2) Massive black hole seeds from low angular momentum material Savvas M. Koushiappas,1 James S. Bullock,2⋆ Avishai Dekel,3 1 Department of Physics, The Ohio State University, 174 W. 18th Ave, Columbus, OH 43210 USA; [email protected] 2 Harvard Smithsonian Center for Astrophysics, 60 Garden St. Cambridge MA 02138 USA; [email protected] 3 Racah Institute of Physics, The Hebrew University, Jerusalem, Israel; [email protected] Released 2002 Xxxxx XX ABSTRACT We present a cosmologically-motivated model in which the seeds of supermassive black holes form out of the lowest angular momentum gas in proto-galaxies at high redshift. We show that under reasonable assumptions, this leads naturally to a cor- relation between black hole masses and spheroid properties, as observed today. We assume that the gas in early-forming, rare-peak haloes has a distribution of specific angular momentum similar to that derived for the dark matter in cosmological N-body simulations. This distribution has a significant low angular momentum tail, which im- plies that every proto-galaxy should contain gas that ends up in a high-density disc. In 7 haloes more massive than a critical threshold of ∼ 7 × 10 M⊙ at z ∼ 15, the discs are gravitationally unstable, and experience an efficient Lin-Pringle viscosity that trans- fers angular momentum outward and allows mass inflow. We assume that this process continues until the first massive stars disrupt the disc. The seed black holes created 5 in this manner have a characteristic mass of ∼ 10 M⊙ , roughly independent of the redshift of formation.
    [Show full text]
  • Dark Matter and Galaxy Formation
    Dark Matter and Galaxy Formation Joel R. Primacka aPhysics Department, University of California, Santa Cruz, CA 95064 USA Abstract. The four lectures that I gave in the XIII Ciclo de Cursos Especiais at the National Observatory of Brazil in Rio in October 2008 were (1) a brief history of dark matter and structure formation in a CDM universe; (2) challenges to CDM on small scales: satellites, cusps, and disks; (3) data on galaxy evolution and clustering compared with simulations; and (4) semi-analytic models. These lectures, themselves summaries of much work by many people, are summarized here briefly. The slides [1] contain much more information. Keywords: Cold dark matter, Cosmology, Dark matter, Galaxies, Warm dark matter PACS: 95.35.+d 98.52.-b 98.52.Wz 98.56.-w 98.80.-k SUMMARY (1) Although the first evidence for dark matter was discovered in the 1930s, it was not until the early 1980s that astronomers became convinced that most of the mass holding galaxies and clusters of galaxies together is invisible. For two decades, theories were proposed and challenged, but it wasn't until the beginning of the 21st century that the CDM ―Double Dark‖ standard cosmological model was accepted: cold dark matter – non-atomic matter different from that which makes up the stars, planets, and us – plus dark energy together making up 95% of the cosmic density. Alternatives such as MOND are ruled out. The challenge now is to understand the underlying physics of the particles that make up dark matter and the nature of dark energy. (2) The CDM cosmology is the basis of the modern cosmological Standard Model for the formation of galaxies, clusters, and larger scale structures in the universe.
    [Show full text]
  • Lecture 4 - Galaxy Formation Theory: Semi-Analytic Models Joel Primack, UCSC
    Lecture 4 - Galaxy Formation Theory: Semi-Analytic Models Joel Primack, UCSC Semi-Analytic Models are currently the best way to understand the formation of galaxies and clusters within the cosmic web dark matter gravitational skeleton. This lecture will discuss the current state of the art in galaxy formation, and describe the successes and challenges for the best current ΛCDM models of the roles of baryonic physics and supermassive black holes in the formation of galaxies. I thank my collaborators Avishai Dekel, Sandra Faber, and Rachel Somerville for some of the slides used in this lecture. What We Know About Galaxy Formation ●Initial Conditions: WMAP5 cosmology CMB + galaxy P(k) + Type Ia SNe → ΩΛ=0.72, Ωm=0.28, Ωb=0.046, H0=70 km/s/Mpc, σ8=0.82 What We Know About Galaxy Formation ●Initial Conditions: WMAP cosmology ●Final Conditions: Low-z galaxy properties Well-studied in Milky Way and nearby galaxies What We Know About Galaxy Formation ●Initial Conditions: WMAP cosmology ●Final Conditions: Low-z galaxies ●Integral Constraints: Cosmological quantities 3 Star Formation Rate Density (SFRD) vs. redshift (M/yr/Mpc ) - Madau plot 3 Stellar Mass Density (SMD) vs. redshift (M/Mpc ) - Dickinson plot t SMD should = integrated SFRD: ρ*(t) = ∫0 dt dρ*/dt Extragalactic Background Light (EBL) - constrains integrated SFRD What We Know About Galaxy Formation ● Initial Conditions: WMAP cosmology ● Final Conditions: Low-z galaxies ● Integral Constraints: Cosmological quantities ● Well-studied galaxy evolution at z<1 SDSS clarified galaxy scaling relations, galaxy color bimodality COMBO-17, DEEP, COSMOS surveys measuring star formation rates, etc. What We Know About Galaxy Formation ●Initial Conditions: WMAP cosmology ●Final Conditions: Low-z galaxies ●Integral Constraints: Cosmological quantities ●Well-studied galaxy evolution at z<1 ●Galaxy Zoo Identified at z=2-3 Lyman break galaxies, Lyman alpha emitters, Distant red galaxies, Active Galactic Nuclei, Damped Lyman alpha systems, Submillimeter galaxies However: Evolutionary sequence unclear.
    [Show full text]