DOCSLIB.ORG

The Planck Satellite and the Cosmic Microwave Background

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
The Planck Satellite and the Cosmic Microwave Background The Cosmic Microwave Background, Dark Matter and Dark Energy Anthony Lasenby, Astrophysics Group, Cavendish Laboratory and Kavli Institute for Cosmology, Cambridge Overview The Cosmic Microwave Background — exciting new results from the Planck Satellite Context of the CMB =) addressing key questions about the Big Bang and the Universe, including Dark Matter and Dark Energy Planck Satellite and planning for its observations have been a long time in preparation — first meetings in 1993! UK has been intimately involved Two instruments — the LFI (Low — e.g. Cambridge is the Frequency Instrument) and the HFI scientific data processing (High Frequency Instrument) centre for the HFI — RAL provided the 4K Cooler The Cosmic Microwave Background (CMB) So what is the CMB? Anywhere in empty space at the moment there is radiation present corresponding to what a blackbody would emit at a temperature of ∼ 2:74 K (‘Blackbody’ being a perfect emitter/absorber — furnace with a small opening is a good example - needs perfect thermodynamic equilibrium) CMB spectrum is incredibly accurately black body — best known in nature! COBE result on this showed CMB better than its own reference b.b. within about 9 minutes of data! Universe History Radiation was emitted in the early universe (hot, dense conditions) Hot means matter was ionised Therefore photons scattered frequently off the free electrons As universe expands it cools — eventually not enough energy to keep the protons and electrons apart — they History of the Universe: superluminal inflation, particle plasma, ‘recombine’ to form atoms of Hydrogen atomic plasma, recombination, Suddenly the photons are able to structure formation free-stream away crossing the entire universe without interruption Universe History History of the Universe: superluminal inflation, particle plasma, atomic plasma, recombination, structure formation Universe History Can see directly today the imprints present at recombination Good evidence these were created by amplification of quantum-generated irregularities during period of inflation, −35 s taking place about 10 after the History of the Universe: superluminal inflation, Big-Bang! particle plasma, atomic plasma, recombination, structure formation http://www.sdss3.org/surveys/boss.php (Chris Blake and Sam Moorfield) Development of these (initially quantum) fluctuations from inflation until recombination, imprints characteristic scales on the universe (basically how far ‘sound’ could have travelled by then) — should see this in both matter and CMB The Power Spectrum Look at power in fluctuations as a function of angular scale on the sky Shown is a theoretical curve Series of coherent peaks is crucial — if can observe them, then fluctuations must have been ‘phased up’ Inflation is only known mechanism for achieving this! Details of peak location and height depend on the cosmological parameters such as density and age of the Universe The ‘Omegas’ refer to densities in various components, and H0 is Hubble’s constant (linked to age) The Power Spectrum Look at power in fluctuations as a function of angular scale on the sky Shown is a theoretical curve Series of coherent peaks is crucial — if can observe them, then fluctuations must have been ‘phased up’ Inflation is only known mechanism for achieving this! Details of peak location and height depend on the cosmological parameters such as density and age of the Universe The ‘Omegas’ refer to densities in various components, and H0 is Hubble’s constant (linked to age) The Power Spectrum Look at power in fluctuations as a function of angular scale on the sky Shown is a theoretical curve Series of coherent peaks is crucial — if can observe them, then fluctuations must have been ‘phased up’ Inflation is only known mechanism for achieving this! Details of peak location and height depend on the cosmological parameters such as density and age of the Universe The ‘Omegas’ refer to densities in various components, and H0 is Hubble’s constant (linked to age) Dark Matter and Dark Energy THE TWO FURTHER INGREDIENTS: We know there are big problems with understanding the dynamics of galaxies and clusters of galaxies There appears to be a large amount of ‘missing mass’ — i.e. inferred dynamically, but not visible Very obvious in the ‘rotation curves’ of galaxies From mv 2 GMm Instead rotational velocity is = flat or even increasing with r r 2 distance! p expect v / 1=r outside galaxy Dark Matter (contd.) For clusters of galaxies, the visible matter is only about 1/10th of that needed to explain the dynamics we see (First pointed out by Fritz Zwicky in 1933 — so this problem has been round a long time!) General consensus is that the A cluster showing lensing ‘missing mass’ is provided by a hitherto undetected particle, which only interacts gravitationally (Though particularly for the galactic rotation curve problem, many attempts also to explain in terms of modifications to the laws of gravity, e.g. MOND theories.) Fritz Zwicky Dark Energy On the largest scales in the universe we see not extra attraction, but ‘repulsion’ The universe is accelerating, as measured by the brightness of distant supernovae Is this Λ? Einstein introduced this into his field equations for General Relativity to try to get a static universe When he realised the universe was expanding, he discarded this term — we finally knew that it was necessary in about 1998 A source term or geometry? Schematically, Einstein’s equations are: G = 8πT a geometrical object derived the stress-energy tensor of from the metricg of spacetime sources of matter and radiation Where does the cosmological constant enter? G − Λg = 8πT Modifies gravity itself or G = 8πT + Λg A new source of energy More generally, should we interpret the late-time acceleration of the universe in terms of a modified gravity theory? — or as the action of e.g. a new form of matter, such as a new scalar field (like the Higgs, recently discovered)? Lambda CDM Putting the two together, we get ΛCDM This is now the ‘standard model of cosmology’ (in analogy with the Standard Model of particle physics) Here dark matter particle is ‘cold’ — basically moving slowly and non-relativistically today Suitable candidates could be e.g. large mass WIMPS And what provides the repulsion for the accelerating universe is a simple cosmological constant Λ This has a constant ratio of pressure to energy density = −1 Other possibilities like scalar fields, this changes with time Key tests come from the CMB power spectrum 4. Flight traj e c to r y of HERSCHEl & PLANCK The launcher’s attitude and trajectory are totally controlled by the two onboard computers, located in the Ariane 5 vehicle equipment bay (VEB). 7.05 seconds after ignition of the main stage cryogenic engine at T-0, the two solid-propellant boosters are ignited, enabling liftoff. The launcher first climbs vertically for 6 seconds, then rotates towards the East. It maintains an attitude that ensures the axis of the launcher remains parallel to its velocity vector, in order to minimize aerodynamic loads throughout the entire atmospheric phase, until the solid boosters are jettisoned. Once this first part of the flight is completed, the onboard computers optimize the trajectory in real time, The Planck Satelliteminimizing propellant consumption to bring the launcher first to the intermediate orbit targeted at the end of the main stage propulsion phase, and then the final orbit at the end of the flight of the cryogenic upper stage. The main stage falls back off the coast of Africa in the Atlantic Ocean (in the Gulf of Guinea). On orbital injection, the launcher will have attained a velocity of approximately 9967 meters/second, and will be at an altitude of about 852 kilometers. The fairing protecting the HERSCHEL, PLANCK spacecraft is jettisoned shortly after the boosters are jettisoned at about T+243 seconds. Planck has been called ‘the coolest spacecraft ever built’! Certainly payload is one of the most complex scientific mission ever put into space Cost 700M euros, and mass at launch 1.9 tonnes It flew out to the Second Lagrangian point (L2) of the Earth/Sun system For more information, visit us on www.arianespace.com 5 Scanning strategy (1 rpm, Semi-stable — flies in a Lissajous plus 1 degree advance per orbit about L2 day) leads to2 × 7 month surveys, each covering entire sky once Planck Science So what did Planck see, and why is it such a big advance? The key is much improved resolution and sensitivity compared to the previous missions At the higher frequencies, each Planck sky map gives about 50 million pixels at each frequency — compare ∼ 3 million for WMAP Sensitivity about 10 times higher per beam Frequency coverage much improved compared to previously as well — can better discriminate the CMB from Galactic and other foregrounds Planck Science So what did Planck see, and why is it such a big advance? The key is much improved resolution and sensitivity compared to the previous missions At the higher frequencies, each Planck sky map gives about 50 million pixels at each frequency — compare ∼ 3 million for WMAP Sensitivity about 10 times higher per beam Frequency coverage much improved compared to previously as well — can better discriminate the CMB from Galactic and other foregrounds Planck Science So what did Planck see, and why is it such a big advance? The key is much improved resolution and sensitivity compared to the previous missions At the higher frequencies, each Planck sky map gives about 50 million pixels at each frequency — compare ∼ 3 million for WMAP Sensitivity about 10 times higher per beam Frequency coverage much improved compared to previously as well — can better discriminate the CMB from Galactic and other foregrounds Planck Cosmology Results 28 papers plus associated data products released Mar 21 Made headlines around the world, including front page of the NY Times Release based on first 15 months of data rest of data (another 15 months) + crucial polarisation data, due in 1 year HFI cryogens ran out in early 2012 — LFI observations finished recently and Planck now ‘de-orbited’ Planck Cosmology Results Broad overview of results wouldPlanck Collaboration: be: Cosmological parameters Table 8.
Load more

Recommended publications
  • Coryn Bailer-Jones Max Planck Institute for Astronomy, Heidelberg
    What will Gaia do for the disk? Coryn Bailer-Jones Max Planck Institute for Astronomy, Heidelberg IAU Symposium 254, Copenhagen June 2008 Acknowledgements: DPAC, ESA, Astrium 1 Gaia in a nutshell • high accuracy astrometry (parallaxes, proper motions) • radial velocities, optical spectrophotometry • 5D (some 6D) phase space survey • all sky survey to G=20 (1 billion objects) • formation, structure and evolution of the Galaxy • ESA mission for launch in late 2011 2 Gaia capabilities Hipparcos Gaia Magnitude limit 12.4 G = 20.0 No. sources 120 000 1 000 000 000 quasars 0 1 million galaxies 0 10 million Astrometric accuracy ~ 1000 μas 12-25 μas at G=15 100-300 μas at G=20 Photometry 2 bands spectra 330-1000 nm Radial velocities none 1-10 km/s to G=17 Target selection input catalogue real-time onboard selection 3 How the accuracy varies • astrometric errors dominated by photon statistics • parallax error: σ(ϖ) ~ 1/√flux ~ distance, d for fixed MV • fractional parallax error: σ(ϖ)/ϖ ~ d2 • fractional distance error: fde ~ d2 • transverse velocity accuracy: σ(v) ~ d2 • Example accuracy • K giant at 6 kpc (G=15): fde = 2%, σ(v) = 1 km/s • G dwarf at 2 kpc (G=16.5): fde = 8%, σ(v) = 0.4 km/s 4 Distance statistics 8kpc At larger distances may use spectroscopic parallaxes 100 000 stars with fde <0.1% 11 million stars with fde <1% panther-observatory.com NGC4565 from Image: 150 million stars with fde <10% 5 Payload overview 6 Instruments 7 Radial velocity spectrograph • R=11 500 • CaII triplet (848-874 nm) • more detailed APE for V < 14 (still millions of stars) 8 Spectrophotometry Figure: Anthony Brown Anthony Figure: Dispersion: 7-15 nm/pixel (red), 4-32 nm/pixel (blue) 9 Stellar parameters • Infer via pattern recognition (e.g.
    [Show full text]
  • Interferometric Orbits of New Hipparcos Binaries
    Interferometric orbits of new Hipparcos binaries I.I. Balega1, Y.Y. Balega2, K.-H. Hofmann3, E.V. Malogolovets4, D. Schertl5, Z.U. Shkhagosheva6 and G. Weigelt7 1 Special Astrophysical Observatory, Russian Academy of Sciences [email protected] 2 Special Astrophysical Observatory, Russian Academy of Sciences [email protected] 3 Max-Planck-Institut fur¨ Radioastronomie [email protected] 4 Special Astrophysical Observatory, Russian Academy of Sciences [email protected] 5 Max-Planck-Institut fur¨ Radioastronomie [email protected] 6 Special Astrophysical Observatory, Russian Academy of Sciences [email protected] 7 Max-Planck-Institut fur¨ Radioastronomie [email protected] Summary. First orbits are derived for 12 new Hipparcos binary systems based on the precise speckle interferometric measurements of the relative positions of the components. The orbital periods of the pairs are between 5.9 and 29.0 yrs. Magnitude differences obtained from differential speckle photometry allow us to estimate the absolute magnitudes and spectral types of individual stars and to compare their position on the mass-magnitude diagram with the theoretical curves. The spectral types of the new orbiting pairs range from late F to early M. Their mass-sums are determined with a relative accuracy of 10-30%. The mass errors are completely defined by the errors of Hipparcos parallaxes. 1 Introduction Stellar masses can be derived only from the detailed studies of the orbital motion in binary systems. To test the models of stellar structure and evolution, stellar masses must be determined with ≈ 2% accuracy. Until very recently, accurate masses were available only for double-lined, detached eclipsing binaries [1].
    [Show full text]
  • A Propensity for Genius: That Something Special About Fritz Zwicky (1898 - 1974)
    Swiss American Historical Society Review Volume 42 Number 1 Article 2 2-2006 A Propensity for Genius: That Something Special About Fritz Zwicky (1898 - 1974) John Charles Mannone Follow this and additional works at: https://scholarsarchive.byu.edu/sahs_review Part of the European History Commons, and the European Languages and Societies Commons Recommended Citation Mannone, John Charles (2006) "A Propensity for Genius: That Something Special About Fritz Zwicky (1898 - 1974)," Swiss American Historical Society Review: Vol. 42 : No. 1 , Article 2. Available at: https://scholarsarchive.byu.edu/sahs_review/vol42/iss1/2 This Article is brought to you for free and open access by BYU ScholarsArchive. It has been accepted for inclusion in Swiss American Historical Society Review by an authorized editor of BYU ScholarsArchive. For more information, please contact [email protected], [email protected]. Mannone: A Propensity for Genius A Propensity for Genius: That Something Special About Fritz Zwicky (1898 - 1974) by John Charles Mannone Preface It is difficult to write just a few words about a man who was so great. It is even more difficult to try to capture the nuances of his character, including his propensity for genius as well as his eccentric behavior edging the abrasive as much as the funny, the scope of his contributions, the size of his heart, and the impact on society that the distinguished physicist, Fritz Zwicky (1898- 1974), has made. So I am not going to try to serve that injustice, rather I will construct a collage, which are cameos of his life and accomplishments. In this way, you, the reader, will hopefully be left with a sense of his greatness and a desire to learn more about him.
    [Show full text]
  • Herschel, Planck to Look Deep Into Cosmos
    Jet APRIL Propulsion 2009 Laboratory VOLUME 39 NUMBER 4 Herschel, Planck to look In a cleanroom at Centre Spatial Guy- deep into anais, Kourou, French Guyana, the Herschel spacecraft is raised cosmos from its transport con- tainer to begin launch Thanks in large part to the preparations. contributions of instruments By Mark Whalen and technologies developed by JPL, long-range views of the universe are about to become much clearer. European European Space Agency When the European Space Agency’s Herschel and wavelengths, continuing to move further into the far like the Hubble Space Telescope and ground-based Planck missions take to the sky together, onboard will infrared. There’s overlap with Spitzer, but Herschel telescopes to view galaxies in the billions, and millions be JPL’s legacy in cosmology studies. extends the range: Spitzer’s wavelength range is 3.5 to more with spectroscopy. In comparison, in the far infra- The pair are scheduled for launch together aboard an 160 microns; Herschel will go from 65 to 672 microns. red we have maybe a few hundred pictures of galaxies Ariane 5 rocket from Kourou, French Guyana on April Herschel’s mirror is much bigger than Spitzer’s and its that emit primarily in the far-infrared, but we know they 29. Once in orbit, Herschel and Planck will be sent angular resolution at the same wavelength will be sub- are important in a cosmological sense, and just the tip on separate trajectories to the second Lagrange point stantially better. of the iceberg. With Herschel, we will see hundreds of (L2), outside the orbit of the moon, to maintain an ap- “Herschel is really critical for studying important pro- thousands of galaxies, detected right at the peak of the proximately constant distance of 1.5 million kilometers cesses like how stars are formed,” said Paul Goldsmith, wavelengths they emit.” (900,000 miles) from Earth, in the opposite direction NASA Herschel project scientist and chief technologist A large fraction of the time with Herschel will be than the sun from Earth.
    [Show full text]
  • Epo in a Multinational Context
    →EPO IN A MULTINATIONAL CONTEXT Heidelberg, June 2013 ESA FACTS AND FIGURES • Over 40 years of experience • 20 Member States • Six establishments in Europe, about 2200 staff • 4 billion Euro budget (2013) • Over 70 satellites designed, tested and operated in flight • 17 scientific satellites in operation • Six types of launcher developed • Celebrated the 200th launch of Ariane in February 2011 2 ACTIVITIES ESA is one of the few space agencies in the world to combine responsibility in nearly all areas of space activity. • Space science • Navigation • Human spaceflight • Telecommunications • Exploration • Technology • Earth observation • Operations • Launchers 3 →SCIENCE & ROBOTIC EXPLORATION TODAY’S SCIENCE MISSIONS (1) • XMM-Newton (1999– ) X-ray telescope • Cluster (2000– ) four spacecraft studying the solar wind • Integral (2002– ) observing objects in gamma and X-rays • Hubble (1990– ) orbiting observatory for ultraviolet, visible and infrared astronomy (with NASA) • SOHO (1995– ) studying our Sun and its environment (with NASA) 5 TODAY’S SCIENCE MISSIONS (2) • Mars Express (2003– ) studying Mars, its moons and atmosphere from orbit • Rosetta (2004– ) the first long-term mission to study and land on a comet • Venus Express (2005– ) studying Venus and its atmosphere from orbit • Herschel (2009– ) far-infrared and submillimetre wavelength observatory • Planck (2009– ) studying relic radiation from the Big Bang 6 UPCOMING MISSIONS (1) • Gaia (2013) mapping a thousand million stars in our galaxy • LISA Pathfinder (2015) testing technologies
    [Show full text]
  • TAPIR TheoreCal Astrophysics Including RelaVity & Cosmology HP
    TAPIR Theore&cal AstroPhysics Including Relavity & Cosmology hp://www.tapir.caltech.edu Chrisan O [email protected], Cahill Center for Astronomy and Astrophysics, Office 338 TAPIR: Third Floor of Cahill, around offices 316-370 ∼20 graduate students 5 senior researchers ∼15 postdocs 5 professors 2 professors emeritus lots visitors TAPIR Research TAPIR Research Topics • Cosmology, Star Forma&on, Galaxy Evolu&on, Par&cle Astrophysics • Theore&cal Astrophysics • Computa&onal Astrophysics • Numerical Rela&vity • Gravitaonal Wave Science: LIGO/eLISA design and source physics TAPIR – Theore&cal AstroPhysics Including Rela&vity 3 TAPIR Research Professors: Sterl Phinney – gravitaonal waves, interacHng black holes, neutron stars, white dwarfs, stellar dynamics Yanbei Chen – general relavity, gravitaonal wave detecHon, LIGO Phil Hopkins – cosmology, galaxy evoluHon, star formaon. Chrisan O – supernovae, neutron stars, computaonal modeling and numerical relavity, LIGO data analysis/astrophysics. Ac&ve Emeritus Professors: Peter Goldreich & Kip Thorne Senior Researchers (Research Professors)/Associates: Sean Carroll – cosmology, extra dimensions, quantum gravity, DM, DE Curt Cutler (JPL) – gravitaonal waves, neutron stars, LISA Lee Lindblom – neutron stars, numerical relavity Mark Scheel – numerical relavity Bela Szilagyi – numerical relavity Elena Pierpaoli (USC,visiHng associate) – cosmology Asantha Cooray (UC Irvine,visiHng associate) – cosmology TAPIR – Theore&cal AstroPhysics Including Rela&vity and Cosmology 4 Cosmology & Structure Formation
    [Show full text]
  • Michael Perryman
    Michael Perryman Cavendish Laboratory, Cambridge (1977−79) European Space Agency, NL (1980−2009) (Hipparcos 1981−1997; Gaia 1995−2009) [Leiden University, NL,1993−2009] Max-Planck Institute for Astronomy & Heidelberg University (2010) Visiting Professor: University of Bristol (2011−12) University College Dublin (2012−13) Lecture program 1. Space Astrometry 1/3: History, rationale, and Hipparcos 2. Space Astrometry 2/3: Hipparcos science results (Tue 5 Nov) 3. Space Astrometry 3/3: Gaia (Thu 7 Nov) 4. Exoplanets: prospects for Gaia (Thu 14 Nov) 5. Some aspects of optical photon detection (Tue 19 Nov) M83 (David Malin) Hipparcos Text Our Sun Gaia Parallax measurement principle… Problematic from Earth: Sun (1) obtaining absolute parallaxes from relative measurements Earth (2) complicated by atmosphere [+ thermal/gravitational flexure] (3) no all-sky visibility Some history: the first 2000 years • 200 BC (ancient Greeks): • size and distance of Sun and Moon; motion of the planets • 900–1200: developing Islamic culture • 1500–1700: resurgence of scientific enquiry: • Earth moves around the Sun (Copernicus), better observations (Tycho) • motion of the planets (Kepler); laws of gravity and motion (Newton) • navigation at sea; understanding the Earth’s motion through space • 1718: Edmond Halley • first to measure the movement of the stars through space • 1725: James Bradley measured stellar aberration • Earth’s motion; finite speed of light; immensity of stellar distances • 1783: Herschel inferred Sun’s motion through space • 1838–39: Bessell/Henderson/Struve
    [Show full text]
  • Lensing and Eclipsing Einstein's Theories
    E INSTEIN’S L EGACY S PECIAL REVIEW Astrophysical Observations: S Lensing and Eclipsing Einstein’s Theories ECTION Charles L. Bennett Albert Einstein postulated the equivalence of energy and mass, developed the theory of interstellar gas, including molecules with special relativity, explained the photoelectric effect, and described Brownian motion in molecular sizes of È1 nm, as estimated by five papers, all published in 1905, 100 years ago. With these papers, Einstein provided Einstein in 1905 (6). Atoms and molecules the framework for understanding modern astrophysical phenomena. Conversely, emit spectral lines according to Einstein_s astrophysical observations provide one of the most effective means for testing quantum theory of radiation (7). The con- Einstein’s theories. Here, I review astrophysical advances precipitated by Einstein’s cepts of spontaneous and stimulated emission insights, including gravitational redshifts, gravitational lensing, gravitational waves, the explain astrophysical masers and the 21-cm Lense-Thirring effect, and modern cosmology. A complete understanding of cosmology, hydrogen line, which is observed in emission from the earliest moments to the ultimate fate of the universe, will require and absorption. The interstellar gas, which is developments in physics beyond Einstein, to a unified theory of gravity and quantum heated by starlight, undergoes Brownian mo- physics. tion, as also derived by Einstein in 1905 (8). Two of Einstein_s five 1905 papers intro- Einstein_s 1905 theories form the basis for how stars convert mass to energy by nuclear duced relativity (1, 9). By 1916, Einstein had much of modern physics and astrophysics. In burning (3, 4). Einstein explained the photo- generalized relativity from systems moving 1905, Einstein postulated the equivalence of electric effect by showing that light quanta with a constant velocity (special relativity) to mass and energy (1), which led Sir Arthur are packets of energy (5), and he received accelerating systems (general relativity).
    [Show full text]
  • ARIEL Payload Design Description
    Doc Ref: ARIEL-RAL-PL-DD-001 ARIEL Payload ARIEL Payload Design Issue: 2.0 Consortium Description Date: 15 February 2017 ARIEL Consortium Phase A Payload Study ARIEL Payload Design Description ARIEL-RAL-PL-DD-001 Issue 2.0 Prepared by: Date: Paul Eccleston (RAL Space) Consortium Project Manager Reviewed by: Date: Kevin Middleton (RAL Space) Payload Systems Engineer Approved & Date: Released by: Giovanna Tinetti (UCL) Consortium PI Page i Doc Ref: ARIEL-RAL-PL-DD-001 ARIEL Payload ARIEL Payload Design Issue: 2.0 Consortium Description Date: 15 February 2017 DOCUMENT CHANGE DETAILS Issue Date Page Description Of Change Comment 0.1 09/05/16 All New document draft created. Document structure and headings defined to request input from consortium. 0.2 24/05/16 All Added input information from consortium as received. 0.3 27/05/16 All Added further input received up to this date from consortium, addition of general architecture and background section in part 4. 0.4 30/05/16 All Further iteration of inputs from consortium and addition of section 3 on science case and driving requirements. 0.5 31/05/16 All Completed all additional sections except 1 (Exec Summary) and 8 (Active Cooler), further updates and iterations from consortium including updated science section. Added new mass budget and data rate tables. 0.6 01/06/16 All Updates from consortium review of final document and addition of section 8 on active cooler (except input on turbo-brayton alternative). Updated mass and power budget table entries for cooler based on latest modelling. 0.7 02/06/16 All Updated figure and table numbering following check.
    [Show full text]
  • Searches for Dark Matter in ATLAS Cristiano Alpigiani
    Searches for dark matter in ATLAS Cristiano Alpigiani on behalf of the ATLAS Collaboration Large Hadron Collider Physics Conference 2017 Shanghai Jiao Tong University Shanghai, 18 May 2017 Dark Matter and Particle Physics Astrophysical evidence for the existence of dark matter ! First observed by Fritz Zwicky " velocity dispersions of galaxies in the Coma cluster (idea neglected for 40 years!) ! Precisely measured by Vera Rubin " velocity of gas near Andromeda • Estimated factor of 10 more dark mass than visible mass ! Planck revealed an almost ! Dark matter web connecting galaxies perfect universe S. Epps & M. Hudson / University of Waterloo esa.it LHCP 2017 Cristiano Alpigiani 2 Whereabouts? Illustration by Sandbox Studio, Chicago with Corinne Mucha …trying to connect the dots… Looking for Dark Matter Dark matter is consistent with non baryonic, stable, and weakly interacting particles at the electroweak scale (WIMP) ! WIMP miracle: matches observed relic density for mass and coupling at ~ EW scale " LHC! ! Many theories beyond the SM predict such particles ! Complementary dark matter experiments (good news!) Indirect detection: DM-DM annihilation process Direct detection: recoil from DM-nucleus scattering At the LHC: # No DM interaction with the detector " missing ET # Initial state radiation to detect it (jets, photons, W, …) # Searches for high-mass di-jet resonances LHCP 2017 Cristiano Alpigiani 4 The ATLAS Experiment ! ATLAS is a multipurpose experiment designed to achieve the highest possible flexibility in different sectors of
    [Show full text]
  • Physicists Look to a New Telescope to Understand Neutron Stars and Matter at the Extremes INNER WORKINGS
    Correction INNER WORKINGS Correction for “Inner Workings: Physicists look to a new tele- scope to understand neutron stars and matter at the extremes,” by Stephen Ornes, which was first published November 4, 2020; 10.1073/pnas.2021447117 (Proc.Natl.Acad.Sci.U.S.A.117, 29249–29252). The editors note that ref. 5 appeared incorrectly. It should instead appear as below. The online version has been corrected. 5. E. Annala, T. Gorda, A. Kurkela, J. Nättilä, A. Vuorinen, Evidence for quark-matter cores in massive neutron stars. Nat. Phys. 16, 907–910 (2020). Published under the PNAS license. First published December 21, 2020. www.pnas.org/cgi/doi/10.1073/pnas.2024053117 CORRECTION www.pnas.org PNAS | December 29, 2020 | vol. 117 | no. 52 | 33719 Downloaded by guest on October 2, 2021 INNER WORKINGS Physicists look to a new telescope to understand neutron stars and matter at the extremes INNER WORKINGS Stephen Ornes, Science Writer Astronomers ostensibly know plenty about neutron matter at such high densities has long been a puzzle,” stars: the hot, collapsed remnants of massive stars says Arzoumanian. Now a small, boxy X-ray telescope that have exploded as supernovae. These objects mounted on the International Space Station is spilling can spin up to hundreds of times a second, generate the inner secrets of these stars. Called the Neutron intense magnetic fields, and send out jets of radia- Star Interior Composition Explorer, or NICER, it can tion that sweep the sky like beams from a lighthouse. measure the size and mass of neutron stars, revealing When two neutron stars collide, the ripples in space- their true density.
    [Show full text]
  • Ay 21 - Galaxies and Cosmology Prof
    Ay 21 - Galaxies and Cosmology Prof. S. G. Djorgovski Winter 2021 Cosmology* as a Science • A study of the universe as a whole, its global geometry, dynamics, history, fate, and its major constituents - galaxies and large-scale structures, their formation and evolution • A basic assumption: the physical laws are the same at all times and everywhere – Some aspects of this are testable – But a new and unexpected physics can show up, e.g., dark matter, dark energy • Only one object of study, and all we can do is look at the surface of the past light cone • Observations tend to be difficult, and subject to biases and selection effects * From Greek kosmos = order; see also cosmetology … The Evolution of the Cosmological Thought … From magical and arbitrary to rational and scientific Folklore to theology to philosophy to physics … Away from anthropocentric/anthropomorphic The Copernican revolution … From final and static to evolving and open-ended The Darwinian revolution … From absolute certainty to an ever expanding sphere of knowledge and a boundary of unknown Cosmology today is a branch of physics Dust Off Your Astronomical Units! • Distance: – Astronomical unit: the distance from the Earth to the Sun, 1 au = 1.496Í1013 cm – Light year: c Í1 yr, 1 ly = 9.463 Í1017 cm – Parsec: the distance from which 1 au subtends an angle of 1 arcsec, 1 pc = 3.086 Í1018 cm = 3.26 ly = 206,264.8 au • Mass and Luminosity: 33 – Solar mass: 1 M = 1.989 Í10 g 33 – Solar luminosity: 1 L = 3.826Í10 erg/s Fluxes and Magnitudes For historical reasons, fluxes in the optical and IR are measured in magnitudes: m = −2.5log10 F + constant Usually integrated over some finite bandpass, e.g., V band (l ~ 550 nm): € fl mV = −2.5log10 F + constant flux integrated over the range l of wavelengths for this band € If the flux is integrated over the entire spectrum, then m is the bolometric magnitude.
    [Show full text]