DOCSLIB.ORG

The Dark Energy Survey and Synergies with CLASH

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
The Dark Energy Survey and Synergies with CLASH The Dark Energy Survey and Synergies with CLASH Ofer Lahav (University College London) 1 Outline • Cosmology @ 2013 • Dark Energy on Mpc scales • The Dark Energy Survey (DES) • The Dark Energy Spectroscopic Instrument (DESI) • Combined Probes • DES-CLASH Synergies 2 The (known) unknown 95% of the universe Observational data: • Gravitational Lensing • Peculiar Velocities • Galaxy Clusters • CMB • Large Scale Structure • Type Ia Supernovae • Integrated Sachs-Wolfe Physical effects: • Geometry • Growth of Structure 3 So what is Dark Energy? • Systematics mimic DE? • Just Lambda-CDM? • Dynamical scalar field? • Signatures of modified gravity? • Inhomogeneous Universe? • Anthropic Principle? Multi-verse? • Something else unpredictable?? Planck CMB results support LCDM: “an almost perfect universe” or “a simple but strange universe”? 4 Redshift Distortion as a test of Dark Energy vs. Modified Gravity 2 ±g (k) = (b + f µ ) ±m(k) f = Ω° 5 Guzzo et al. 2008 Blake et al. 2011 Bound Systems (L-T-B) Given observed r, v, t &Λ Can solve for M Cf. spherical collapse: Lahav et al. (1991); Wang & Steinhardt (1998); Nandra, Lasenby & Hobson (2013) Weighing the Local Group in the presence of Dark Energy Partridge, Lahav & Hoffman (arXiv:1308.0970, MNRAS) • At present the Milky Way and Andromeda are: * separated by r = 770 ±40 kpc * infall at v = -109 ±4 km/sec (Van der Marel 2012) • Given the age of the universe t=13.81 ± 0.06 Gyr and Dark Energy fraction of 69% (Planck 2013) 12 we find that the mass is (4.73 ± 1.03) x 10 Msun • Mass 13% higher than in the absence of Lambda cf. Kahn & Woltjer (1959); Lynden-Bell (1981) Chernin et al. (2009), Binney & Tremaine (2008) Mass calibration with 16 simulated galaxy pairs • Mvir/Mta = 1.34 ± 0.26 • Mvir/MtaΛ = 1.04 ±0.16 • Estimate for LG: 12 Mvir /10 Msun = 4.92 ±1.08(obs) ±0.79(sys) Partridge, Lahav & Hoffman (2013)CLUES simulations (Cf. Li and White 2008) Timeline of cosmology projects 2010 2015 2020 2000 2005 MOS: 2dFGRS (e)BOSS DESI EUCLID Imaging: SDSS DES LSST&EUCLID $1 per galaxy! The Dark Energy Survey First Light in 9/12, Survey just started 9/13 w Multi-probe approach CTIO Cluster Counts Weak Lensing Large Scale Structure Supernovae Ia w 8-band survey 5000 deg2 grizY 300 million photometric redshifts + JHK from VHS VISTA +SPT SZ clusters 10 THE DES COLLABORATION DES Science Committee w SC Chair: O. Lahav w Large Scale Structure: E. Gaztanaga & W. Percival w Weak Lensing: S. Bridle & B. Jain w Clusters: J. Mohr & C. Miller w SN Ia: M. Sako & B. Nichol w Photo-z: F. Castander & H. Lin w Simulations: G. Evrard & A. Kravtsov w Galaxy Evolution: D. Thomas & R. Wechsler w QSO: P. Martini & R. McMahon w Strong Lensing: L. Buckley-Geer & M. Makler w Milky Way: B. Santiago & B. Yanny w Theory & Combined Probes: S. Dodelson & J. Weller w + Spectroscopic task force: F. Abdalla & A. Kim w + Ad-hoc Committees Regular WG telecons; Monthly SC telecons; sessions at collaboration meetings; reports to the DES Director, ExeC & MC 12 The Dark Energy Survey DES FIRST LIGHT NGC 1365 0.8” images recorded within first few nights of first light! Fornax Cluster Highlights from DES earlyThe data BIGGER picture Mass & light maps of massive galaxy clusters from early DECam data Bob Armstrong Elisabeth Krause David Bacon Huan Lin Keith Bechtol Niall McCrann Sarah Bridle Ken Patton Fabrice Brimioulle Andres Plazas Joseph Clampitt Barnaby Rowe Daniel Gruen Eduardo Rozo Michael Hirsch Eli Rykoff Klaus Honscheid Stella Seitz Eric Huff Eric Suchyta Bhuv Jain Rafal Szepietowski Mike Jarvis Vinu Vikram Stephanie Jouvel Julia Young Tomasz Kacprzak ... and the DES SV squad 7 confirmed SN, A new cluster Mass Peter Melchior 5 of them SNIa @ z= 0.87 reconstruction of cluster RXJ2248 @z=0.35 A142 @ z=0.25 DES gri VHS K Systematics - Mind the Gap! 16 Cosmic shear measurement Shear is 1% effect, to be measured to 1% to get w to 1% GREAT08 (Bridle et al.); GREAT10 (Kitching et al.); GREAT3 (Mandelbaum & Rowe et al) Photo-z –Spectra cross talk • Approximately, for a photo-z slice: -1/2 (δw/ w) = 5 (δz/ z) = 5 (σz/z) Ns => the target accuracy in w and photo-z scaer σz dictate the number of required 5 6 spectroscopic redshis Ns =10 -10 18 DESI – Spectroscopic Survey “10 times BOSS” Mayall telescope available up to 100% of dark time," 5000 fibres, 20min base integration time" 20 million targets" 18,000 deg2 survey" 1 million Ly-A QSOs +2.5 million QSOs DESI 18 million ELGs 4 million LRGs Combining imaging and spectroscopy Dark Energy (W0, Wa) Mod Grav (Q, R) 2 5 ee FoM = 1.6 ee MGFoM = 0.3 nn MGFoM = 0.6 4 nn FoM = 0.9 1.8 ee + nn FoM = 7.2 ee + nn MGFoM = 50.1 ee + ne + nn FoM = 27.8 ee + ne + nn MGFoM = 112.7 3 1.6 2 1.4 1 1.2 )/2 0 R a + 1 w 0 (1 0 −1 Q 0.8 −2 0.6 −3 0.4 −4 0.2 −5 0 −2 −1.5 −1 −0.5 0 −4 −2 0 2 4 6 w Q 0 0 • DES-like WGL + DESI-like LSS (incl. RSDs) • Assumes 5000 sq deg for each survey, • 300 million DES galaxies, 10 million DESI galaxies Kirk, Lahav, Bridle, Jouvel, Abdalla, Frieman, arXiv:1307.8062 EUCLID (“Whole-Sky CLASH”) ESA Cosmic Vision planned launch 2020 * Weak lensing from space + photo-z from the ground * 15000 sq deg 1B galaxy images * * 50M spectra (+ground based projects, e.g. PS, DES, LSST,…) 21 CLASH:UCL OL joined the 2009 proposal (thanks to Tom Broadhurst!) UCL Post-docs: Ole Host and Stephanie Jouvel Manda Banerji (new participant) Papers: * Photo-z - Jouvel, Host, OL, & CLASH team (ArXiv:1308.0063, A&A) * LSS foreground in SL - Host (ArXiv: 1110.5331, MNRAS) MACS1206 22 RXJ2248 3125 CLASH galaxies 387 DES matches CLASH& DES& Banerji et al. (in prep) 23 3-6 CLASH clusters in the DES 5000 sq deg footprint RXJ2248 already observed by DES 24 CLASH-DES joint projects • Derive scaling relations fron the the 25 CLASH clusters as input for DES cluster mass function (via conditional probabilities!) • RXJ2248: DES-CLASH-WFI-VHS-… calibration of photometry, photo-z and shapes • LBG Luminosity Function @ z=5: - bright-end from DES - faint-end from CLASH • Other ideas? 25 .
Load more

Recommended publications
  • Annual Review 2011/12
    UCL DEPARTMENT OF PHYSICS AND ASTRONOMY PHYSICS AND ASTRONOMY 2011–12 ANNUAL REVIEW PHYSICS AND ASTRONOMY ANNUAL REVIEW 2011–12 Contents Welcome It is an honour to write this WELCOME 1 introduction standing, to misquote Newton, on the shoulders of giants. COMMUNITY FOCUS 3 Jonathan Tennyson finished his Teaching Lowdown 4 tenure as Head of Department in September 2011 and so the majority Student Accolades 4 of the material contained in this Outstanding PhD Theses Published 5 Review records achievements under his leadership. In addition, Tony Career Profiles 6 Harker is currently acting as Head of Science in Action 8 Department in many matters and will continue to do so until October 2012. Alumni Matters 9 This is due to my on-going commitments with the ATLAS experiment on the ACADEMIC SHOWCASE 11 Large Hadron Collider (LHC) at CERN. Staff Accolades 12 I currently spend a large amount of my time in Geneva and I am very grateful Academic Appointments 14 to both Tony and Jonathan, as well as to other members of staff for helping Doctor of Philosophy (PhD) 15 to make this transition a success. In Portrait of Dr Phil Jones 16 particular I would also like to thank Hilary Wigmore as Departmental Manager and Raman Prinja as the new Director of RESEARCH SPOTLIGHT 17 Teaching for their continued support. Atomic, Molecular, Optical and Position Physics (AMOPP) 19 High Energy Physics (HEP) 21 “Success in such long- Condensed Matter and term, high-impact projects Materials Physics (CMMP) 25 requires sustained vision Astrophysics (Astro) 29 and dedicated work by Biological Physics (BioP) 33 excellent scientists over Research Statistics 35 many years.” Staff Snapshot 38 Underpinning this success is the outstanding quality of scientific research and education within the Department.
    [Show full text]
  • The Practical Use of Cosmic Shear As a Probe of Gravity
    The Practical use of Cosmic Shear as a Probe of Gravity Donnacha Kirk Thesis submitted for the Degree of Doctor of Philosophy of the University College London Department of Physics & Astronomy UNIVERSITY COLLEGE LONDON April 2011 I, Donnacha Kirk, confirm that the work presented in this thesis is my own. Where information has been derived from other sources, I confirm that this has been indicated in the thesis. Specifically: • The work on luminosity functions and red galaxy fractions in section 2.7 was done by Dr. Michael Schneider (then at Durham) as part of our collaboration on the paper Kirk et al. (2010). • The work in chapters 3 & 4 is my contribution to, and will form the substantial part of, papers in preparation with collaborators Prof. Rachel Bean and Istvan Lazslo at Cornell University. The MG effect on the linear growth function was computed by Istvan Lazslo. • The Great08 section of chapter 6 draws on my contributions to the Great08 Handbook (Bridle et al. 2009), Great08 Results Paper (Bridle et al. 2010a) and Great10 Handbook (Kitching et al. 2010). To Mum and Dad, for everything. Boyle. ... an’ it blowed, an’ blowed – blew is the right word, Joxer, but blowed is what the sailors use... Joxer. Aw, it’s a darlin’ word, a daarlin’ word. Boyle. An’, as it blowed an’ blowed, I often looked up at the sky an’ assed meself the question – what is the stars, what is the stars? Voice of Coal Vendor. Any blocks, coal-blocks; blocks, coal-blocks! Joxer. Ah, that’s the question, that’s the question – what is the stars? Boyle.
    [Show full text]
  • Sum of the Masses of the Milky Way and M31: a Likelihood-Free Inference Approach Pablo Lemos, Niall Jeffrey, Lorne Whiteway, Ofer Lahav, Noam I
    Sum of the masses of the Milky Way and M31: A likelihood-free inference approach Pablo Lemos, Niall Jeffrey, Lorne Whiteway, Ofer Lahav, Noam I. Libeskind, Yehuda Hoffman To cite this version: Pablo Lemos, Niall Jeffrey, Lorne Whiteway, Ofer Lahav, Noam I. Libeskind, et al.. Sum ofthe masses of the Milky Way and M31: A likelihood-free inference approach. Phys.Rev.D, 2021, 103 (2), pp.023009. 10.1103/PhysRevD.103.023009. hal-02999468 HAL Id: hal-02999468 https://hal.archives-ouvertes.fr/hal-02999468 Submitted on 26 Apr 2021 HAL is a multi-disciplinary open access L’archive ouverte pluridisciplinaire HAL, est archive for the deposit and dissemination of sci- destinée au dépôt et à la diffusion de documents entific research documents, whether they are pub- scientifiques de niveau recherche, publiés ou non, lished or not. The documents may come from émanant des établissements d’enseignement et de teaching and research institutions in France or recherche français ou étrangers, des laboratoires abroad, or from public or private research centers. publics ou privés. PHYSICAL REVIEW D 103, 023009 (2021) Sum of the masses of the Milky Way and M31: A likelihood-free inference approach Pablo Lemos ,1,* Niall Jeffrey ,2,1 Lorne Whiteway ,1 Ofer Lahav,1 Noam Libeskind I,3,4 and Yehuda Hoffman5 1Department of Physics and Astronomy, University College London, Gower Street, London WC1E 6BT, United Kingdom 2Laboratoire de Physique de l’Ecole Normale Sup´erieure, ENS, Universit´e PSL, CNRS, Sorbonne Universit´e, Universit´e de Paris, Paris, France 3Leibniz-Institut
    [Show full text]
  • Curriculum Vitae
    CURRICULUM VITAE FULL NAME: George Petros EFSTATHIOU NATIONALITY: British DATE OF BIRTH: 2nd Sept 1955 QUALIFICATIONS Dates Academic Institution Degree 10/73 to 7/76 Keble College, Oxford. B.A. in Physics 10/76 to 9/79 Department of Physics, Ph.D. in Astronomy Durham University EMPLOYMENT Dates Academic Institution Position 10/79 to 9/80 Astronomy Department, Postdoctoral Research Assistant University of California, Berkeley, U.S.A. 10/80 to 9/84 Institute of Astronomy, Postdoctoral Research Assistant Cambridge. 10/84 to 9/87 Institute of Astronomy, Senior Assistant in Research Cambridge. 10/87 to 9/88 Institute of Astronomy, Assistant Director of Research Cambridge. 10/88 to 9/97 Department of Physics, Savilian Professor of Astronomy Oxford. 10/88 to 9/94 Department of Physics, Head of Astrophysics Oxford. 10/97 to present Institute of Astronomy, Professor of Astrophysics (1909) Cambridge. 10/04 to 9/08 Institute of Astronomy, Director Cambridge. 10/08 to present Kavli Institute for Cosmology, Director Cambridge. PROFESSIONAL SOCIETIES Fellow of the Royal Society since 1994 Fellow of the Instite of Physics since 1995 Fellow of the Royal Astronomical Society 1983-2010 Member of the International Astronomical Union since 1986 Associate of the Canadian Institute of Advanced Research since 1986 1 AWARDS/Fellowships/Major Lectures 1973 Exhibition Keble College Oxford. 1975 Johnson Memorial Prize University of Oxford. 1977 McGraw-Hill Research Prize University of Durham. 1980 Junior Research Fellowship King’s College, Cambridge. 1984 Senior Research Fellowship King’s College, Cambridge. 1990 Maxwell Medal & Prize Institute of Physics. 1990 Vainu Bappu Prize Astronomical Society of India.
    [Show full text]
  • Prof. Ofer Lahav: Curriculum Vitae
    Prof. Ofer Lahav: Curriculum Vitae Department of Physics and Astronomy Phone: +44 (0) 20 7679 3473 University College London (UCL) Mobile: +44 (0) 7738848597 Gower Street E-mail: [email protected] London WC1E 6BT Web: www.homepages.ucl.ac.uk/~ucapola/ United Kingdom Home address: 3 Monks Close Canterbury CT2 7ET Current position Perren Chair of Astronomy Department of Physics & Astronomy, UCL Other current roles Co-Chair of the Science Committee of the international Dark Energy Survey Vice-Dean for Research, Faculty of Mathematical and Physical Sciences, UCL Holder of a European Research Council Advanced Grant (2012-2017) Date and Place of Birth: 5 April 1959; Tiberias, Israel Citizenship: Israeli and British Education University of Cambridge: Astronomy Ph.D., 1988 (Supervisors: Prof. G. Efstathiou and Prof. D. Lynden-Bell) Ben-Gurion University: Physics M.Sc., 1985 (Supervisor: Prof. J. Bekenstein) Tel-Aviv University: Physics B.Sc., 1980 Positions 2004- Perren Professor of Astronomy, UCL 2011- Vice-Dean for Research, Faculty of Mathematical and Physical Sciences, UCL 2004-2011 Head of Astrophysics, Physics & Astronomy Department, UCL 2000-2003 Reader in Cosmology, Institute of Astronomy, Cambridge University 1998-1999 on leave as Associate Professor, the Hebrew University, Jerusalem 1990-2000 Member of staff, Institute of Astronomy, Cambridge University (Senior Assistant in Research, Assistant Director of Research, Lecturer) 1989 Post-doctoral Fellow, Institute for Advanced Study, Princeton 1988-2003 Research Fellow (1988-91) and then
    [Show full text]
  • Physics and Astronomy ANNUAL REVIEW 2013–14 UCL DEPARTMENT of PHYSICS and ASTRONOMY
    Physics and Astronomy ANNUAL REVIEW 2013–14 UCL DEPARTMENT OF PHYSICS AND ASTRONOMY PHYSICS AND ASTRONOMY ANNUAL REVIEW 2014–15 1 WELCOME Physics and Astronomy ANNUAL REVIEW 2013–14 Contents Welcome 1 WELCOME The year 2014 ended with the The tragic death of Bruce Swinyard 2 COMMUNITY FOCUS announcement of the Research in May 2015 was a great loss, and Excellence Framework results, an our thoughts are with his family. A full 3 Teaching Lowdown important exercise in which all UK obituary appears on page 13. universities are assessed on their 4 Student Accolades research activities, and on which Several members of the department 6 Students in Action funding allocations are then based. received prizes in 2014: Benjamin The Department formed the bulk of Joachimi and Ofer Lahav won awards 8 Career Profile UCL’s ‘Physics’ submission, with major from the Royal Astronomical society, contributions also from our colleagues in 9 Alumni Matters as did the Herschel and Cassini teams the London Centre for Nanotechnology which have several UCL members. 10 Science in Action and in the Mullard Space Science David Walker won the IoP Optics and Laboratory. 11 ACADEMIC SHOWCASE Photonics prize, Angela Occhiogrosso and Jennifer Chan won the faculty 12 Staff News postgraduate research and taught 13 Obituary course prizes, respectively. Steve …the department is Fossey won the UCL Communications 14 Staff Accolades “ and Culture award (remember the 15 Portrait of… strong and confdent. supernova discovery in Messier 82 from We will meet these the last review!). Matthew Wing won 16 Reserch Degrees the Friedrich Wilhelm Bessel Research challenges together, and Award from the Humboldt Foundation, 17 RESEARCH SPOTLIGHT continue to prosper.
    [Show full text]
  • The Royal Astronomical Society Since 2010
    ROYAL ASTRONOMICAL SOCIETY Burlington House, Piccadilly London W1J 0BQ, UK T: 020 7734 4582 F: 020 7494 0166 [email protected] www.ras.org.uk Registered Charity 226545 ELECTION OF OFFICERS AND COUNCIL – 2015 Biographical Notes of Candidates President Elect OFER LAHAV (A) BSc (Tel-Aviv U) , MSc (Ben-Gurion U), PhD (Cambridge U), FRAS, FintP, Perren Professor of Astronomy, University College London (since 2004), formerly Head of UCL Astrophysics (2004-2011), formerly member of staff at the Institute of Astronomy Cambridge U (1990-2003), currently Vice-Dean (Research) of UCL’s Faculty of Mathematical and Physical Sciences, holder of a European Research Council Advanced Grant, co-chair of the international Dark Energy Survey Science Committee and chair of DES:UK, co-authored over 200 refereed papers, supervised 18 PhD students, served as RAS Council member (2009-2012), Vice-President (2010-2012; chaired the Awards and International committees), editor of MNRAS (2006-2008), Awarded the RAS 2014 Gerald Whitrow Lecture, and the 2008 RAS Group Award to the 2dFGRS team. Research interests: cosmological probes of dark matter and dark energy, large galaxy surveys, statistical methods, history of astronomy. Statement: I am keen to enhance the RAS profile and its connection to the UK Research Councils, and other societies (e.g. RS, IoP, EAS, IAU), as well as to explore funding opportunities through the EU and charity organizations, and to run a fund-raising campaign for RAS@200. The RAS would be strengthened by a closer connection between the Astronomy and Geophysics sections of the RAS, to be achieved in the first instance by initiating meetings with a common interest, e.g.
    [Show full text]
  • Optimising Spectroscopic and Photometric Galaxy Surveys: Same-Sky Benefits for Dark Energy and Modified Gravity
    Mon. Not. R. Astron. Soc. 000, 1–21 (2009) Printed 12 September 2018 (MN LATEX style file v2.2) Optimising Spectroscopic and Photometric Galaxy Surveys: Same-sky Benefits for Dark Energy and Modified Gravity Donnacha Kirk1, Ofer Lahav1, Sarah Bridle2, Stephanie Jouvel3, Filipe B. Abdalla1, Joshua A. Frieman4 1Department of Physics & Astronomy, University College London, Gower Street, London, WC1E 6BT, UK 2Jodrell Bank Centre for Astrophysics, School of Physics and Astronomy, The University of Manchester, Manchester, M13 9PL, UK 3Institut de Ci`encies de l’Espai (ICE, IEEC/CSIC), E-08193 Bellaterra (Barcelona), Spain 4Fermilab Center for Particle Astrophysics, Batavia, IL 60510 4Kavli Institute for Cosmological Physics, The University of Chicago, Chicago, IL 60637 12 September 2018 ABSTRACT The combination of multiple cosmological probes can produce measurements of cosmo- logical parameters much more stringent than those possible with any individual probe. We examine the combination of two highly correlated probes of late-time structure growth: (i) weak gravitational lensing from a survey with photometric redshifts and (ii) galaxy clustering and redshift space distortions from a survey with spectroscopic redshifts. We choose generic survey designs so that our results are applicable to a range of current and future photometric redshift (e.g. KiDS, DES, HSC, Euclid) and spectroscopic redshift (e.g. DESI, 4MOST, Sumire) surveys. Combining the surveys greatly improves their power to measure both dark energy and modified gravity. An independent, non-overlapping combination sees a dark energy figure of merit more than 4 times larger than that produced by either survey alone. The powerful syner- gies between the surveys are strongest for modified gravity, where their constraints are orthogonal, producing a non-overlapping joint figure of merit nearly 2 orders of magnitude larger than either alone.
    [Show full text]
  • Science from Overlapping Lensing / Spec-Z Surveys
    Science from overlapping lensing / spec-z surveys Chris Blake (Swinburne) Probes of the cosmological model How fast is the Universe How fast are structures expanding with time? growing within it? Redshift-space distortions • RSD allow spectroscopic galaxy surveys to measure the growth rate of structure coherent virialized flows infalling motions galaxies observer Why combination of lensing and RSD? • Sensitive to theories of gravity in complementary ways • General perturbations to FRW metric: • are metric gravitational potentials, identical in General Relativity but can differ in general theories • Relativistic particles (e.g. light rays for lensing) collect equal contributions and are sensitive to • Non-relativistic particles (e.g. galaxies infalling into clusters) experience the Newtonian potential Applications 12 F. Simpson et al. 0.9 arXiv:1212.3339Mon.0.8 Not. R. Astron. Soc. 000, 000–000 (0000) Printed 17 December 2012 (MN LATEX style file v2.2) CFHTLenS:0.7 Testing the Laws of Gravity with Tomographic Weak Lensing and Redshift Space Distortions 0.6 1! 1 2 3 13 Fergus0.5 Simpson , Catherine Heymans , David Parkinson , Chris Blake , Martinφ Kilbinger4,5,6, Jonathan Benjamin7, Thomas Erben8, Hendrik Hildebrandt7,8, Henk Hoekstra9,10, Thomas D. Kitching1, Yannick Mellier11, Lance Miller12, Ludovic0.4 Van Waerbeke7, Jean Coupon13, Liping Fu14, Joachim Harnois-Deraps´ 15,16, Michael J. Hudson17,18, Konrad Kuijken9, Barnaby Rowe19,20, Tim Schrabback8,9,21, Elisabetta0.3 Semboloni9, Sanaz Vafaei7, Malin Velander12,9. 1Scottish Universities Physics Alliance, Institute for Astronomy, University of Edinburgh, Royal Observatory, Blackford Hill, Edinburgh, EH9 3HJ, UK. 2School of Mathematics and Physics, University of Queensland, Brisbane, QLD 4072, Australia 3Centre0.2 for Astrophysics & Supercomputing, Swinburne University of Technology, P.O.
    [Show full text]
  • Dark Energy: Is Itjust'einstein's Cosmological Constant Lambda?
    Dark Energy: is it `just' Einstein's Cosmological Constant Λ? Ofer Lahava a Department of Physics & Astronomy, University College London, Gower Street, London WC1E 6BT, UK ARTICLE HISTORY Compiled September 23, 2020 ABSTRACT The Cosmological Constant Λ, a concept introduced by Einstein in 1917, has been with us ever since in different variants and incarnations, including the broader con- cept of `Dark Energy'. Current observations are consistent with a value of Λ corre- sponding to about present-epoch 70% of the critical density of the Universe. This is causing the speeding up (acceleration) of the expansion of the Universe over the past 6 billion years, a discovery recognised by the 2011 Nobel Prize in Physics. Coupled with the flatness of the Universe and the amount of 30% matter (5% baryonic and 25% `Cold Dark Matter'), this forms the so-called ‘ΛCDM standard model', which has survived many observational tests over about 30 years. However, there are cur- rently indications of inconsistencies (`tensions' ) within ΛCDM on different values of the Hubble Constant and the clumpiness factor. Also, time variation of Dark Energy and slight deviations from General Relativity are not ruled out yet. Several grand projects are underway to test ΛCDM further and to estimate the cosmological parameters to sub-percent level. If ΛCDM will remain the standard model, then the ball is back in the theoreticians' court, to explain the physical meaning of Λ. Is Λ an alteration to the geometry of the Universe, or the energy of the vacuum? Or maybe it is something different, that manifests a yet unknown higher-level theory? KEYWORDS Cosmology, Dark Matter, Cosmological Constant, Dark Energy, galaxy surveys 1.
    [Show full text]
  • Prof. Ofer Lahav: Curriculum Vitae
    Prof. Ofer Lahav: Curriculum Vitae Department of Physics and Astronomy Phone: +44 (0) 20 3549 5813 University College London (UCL) Mobile: +44 (0) 7738848597 Gower Street E-mail: [email protected] London WC1E 6BT Web: www.homepages.ucl.ac.uk/~ucapola/ United Kingdom Home address: 3 Monks Close Canterbury CT2 7ET Current position - Perren Chair of Astronomy, Department of Physics & Astronomy, UCL Other current roles - Chair of the UK consortium of the Dark Energy Survey (DES) and Chair of the DES Advisory Board - Principal Investigator of a European Research Council (ERC) Advanced Grant ‘TESTDE’ - Member of the Science Board, Science and Technology Facilities Council (STFC) - Co-Director, STFC-supported Centre for Doctoral Training (CDT) in Data Intensive Science, UCL Date and Place of Birth: 5 April 1959; Tiberias, Israel Citizenship: Israeli and British Education University of Cambridge: Astronomy Ph.D., 1988 (Supervisors: Prof. G. Efstathiou and Prof. D. Lynden-Bell) Ben-Gurion University: Physics M.Sc., 1985 (Supervisor: Prof. J. Bekenstein) Tel-Aviv University: Physics B.Sc., 1980 Positions 2004- Perren Professor of Astronomy, UCL 2011-2015 Vice-Dean for Research, Faculty of Mathematical and Physical Sciences, UCL 2004-2011 Head of Astrophysics, Physics & Astronomy Department, UCL 2000-2003 Reader in Cosmology, Institute of Astronomy, Cambridge University 1998-1999 on leave as Associate Professor, the Hebrew University, Jerusalem 1990-2000 Member of staff, Institute of Astronomy, Cambridge University (Senior Assistant in Research,
    [Show full text]
  • Prof. Ofer Lahav: Curriculum Vitae (21 April 2021)
    Prof. Ofer Lahav: Curriculum Vitae (21 April 2021) Department of Physics and Astronomy Phone: +44 (0) 20 3549 5813 (w) University College London (UCL) Phone: +44 (0) 7738848597 (m) Gower Street E-mail: [email protected] London WC1E 6BT Web: http://www.homepages.ucl.ac.uk/~ucapola/ United Kingdom Citizenship: British and Israeli Research Focus: Observational Cosmology, in particular probing and characterising Dark Matter and Dark Energy from large galaxy surveys; Data Intensive Science and AI in Astronomy Current position • Perren Chair of Astronomy, Department of Physics & Astronomy, UCL Other current roles • Vice-Dean (International), Faculty of Mathematical and Physical Sciences, UCL • Co-Director, STFC Centre for Doctoral Training (CDT) in Data Intensive Science, UCL • Chair of the UK consortium of the Dark Energy Survey (DES) • Chair of the UK consortium of the Dark Energy Spectroscopic Instrument (DESI) • Visiting Fellow, All Souls College, Oxford (until the end of June 2021) Education • University of Cambridge: Astronomy PhD, 1988 (Supervisors: Prof G Efstathiou, Prof D Lynden-Bell) • Ben-Gurion University: Physics MSc, 1985 (Supervisor: Prof. J Bekenstein) • Tel-Aviv University: Physics BSc, 1980 Previous Positions 2011-2015: Vice-Dean for Research, Faculty of Mathematical and Physical Sciences, UCL 2004-2011: Head of Astrophysics, Physics & Astronomy Department, UCL 2000-2003: Reader in Cosmology, Institute of Astronomy, Cambridge University 1998-1999: on leave as Associate Professor, the Hebrew University, Jerusalem 1990-2000:
    [Show full text]