Gravitational lensing an astrophysical tool

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1 Ivanfest III 22 May 2012 After the solar eclipse of 1919 and papers in 1930 s subject of g.l. nearly abandoned for about 30 years Astronomy Department - University of Washington Gravitational lensing an astrophysical tool Georges Meylan Laboratoire d astrophysique Ecole Polytechnique Fédérale de Lausanne (EPFL) in collaboration with : Frédéric Courbin, Alexander Eigenbrod, Malte Tewes at EPFL George Djorgovski, Ashish Mahabal at Caltech, Chris Kochanek, Chris Morgan at OSU, and many others 1960 s 1970 s Theoretical discussions Invention of CCDs Discovery of quasars In 1979, first case of a gravitational lens extragalactic at cosmological distance QSO Walsh, Carswell, Weymann, 1979, Nature, 279, 381 The disruptive action of the lensing galaxy splits the single image of the quasar into two or more componants QSO : first gravitational lens at cosmological distance QSO A HST/WFPC2 QSO Δ(A,B) = 6.1 V A = V B 17.1 z(source) = 1.41 µ = dω dω i s = magnification QSO B V G = 19.1 z(lens) = 0.36 HST Castles

2 QSO : first gravitational lens at cosmological distance Image A Image B Δ(A,B) = 6.1 V A = V B 17.1 z(source) = 1.41 All pairs of quasars observed in the Universe do not always proceed from the effect of a gravitational lens CIV 1549Å CIII] 1909Å MgII 2798Å Walsh, Carswell, Weymann 1979, Nature, 279, 381 PKS : first tight pair of quasars PKS : first tight pair of quasars z = Radio image from VLA I A /I B = 2.7 in V A B I A /I B > 10 4 in radio Δ(A,B) = 4.2 Distance ~ MW-LMC Djorgovski, Perley, Meylan, McCarthy, 1987, ApJ, 321, L17 Djorgovski et al., 1987, ApJ, 321, L17

PKS 1145-071 : first tight pair of quasars Radio image from VLA I A /I B = 2.7 in V I A /I B > 10 4 in radio Δ(A,B) = 4.2 Distance ~ MW-LMC QQ 1429-008 : Discovery of a probable triple QSO at z = 2.

3 PKS : first tight pair of quasars Radio image from VLA I A /I B = 2.7 in V I A /I B > 10 4 in radio Δ(A,B) = 4.2 Distance ~ MW-LMC QQ : Discovery of a probable triple QSO at z = A C B Djorgovski & Meylan, 1987, ApJ, 321, L17 Second pair of quasars : PHL 1222 Meylan & Djorgovski 1989 S. G. Djorgovski, F. Courbin, G. Meylan, D. Sluse, D. Thompson, A. Mahabal, E. Glikman, 2007, ApJL, 662, 1 Keck spectra of the QSO components : all at z = a1 a1 a1 a2 8 What about the lensing galaxy? Our best lensing model predicts a massive and luminous lens galaxy, which is not seen, even if placed in an optimal position : physical close triplet of QSOs C 4 a3 a1 a1 a3 a1 a3 a3 Keck-VLT deep imaging D? B 3 a3 λ obs (Å) Absorbers: z a1 = (A,B), z a2 = (A), z a3 = (B,C) A R band (VLT) MCS deconvolution 3 arcsec Disturbed host 2 galaxy? AAS mtg. Jan 07 Djorgovski et al

Our best lensing model predicts a massive and luminous lens galaxy, which is not seen, even if placed in an optimal position : physical close triplet of QSOs 8 Keck-VLT deep imaging What about the

4 Our best lensing model predicts a massive and luminous lens galaxy, which is not seen, even if placed in an optimal position : physical close triplet of QSOs 8 Keck-VLT deep imaging What about the lensing galaxy? D? C 4 B 3 Gravitational Lensing Theory A R band (VLT) MCS deconvolution 3 arcsec Disturbed host 2 galaxy? AAS mtg. Jan 07 Djorgovski et al directions : - to the lens - to the source - to the image 3 angles : - α β θ 3 plans : - of the source η - of the image ξ - of the observer 3 distances : - D s D d D ds The lens equation The positions of the source and of the images are related by a non linear equation providing the possibility of multiple images : multiple image positions! θ! corresponding to a unique source position β β = θ α ( θ )

The gravitational lenses classified following three regimes : STRONG : the source is imaged into several componants, their shapes and luminosities are strongly perturbed WEAK : one single image of

application source plane lens plane are described by its jacobian matrix : A β / θ With the convergence κ and the shear γ : Abell 1689 HST ACS (2003) z amas = 0.182 & 1 A = (1 κ ) $ % 0 0# & cos2φ!

5 The gravitational lenses classified following three regimes : STRONG : the source is imaged into several componants, their shapes and luminosities are strongly perturbed WEAK : one single image of the source, with its shape and luminosity strongly perturbed MICRO : one single image of the source, with only its luminosity strongly perturbed Convergence and shear The local properties of the application source plane lens plane are described by its jacobian matrix : A β / θ With the convergence κ and the shear γ : Abell 1689 HST ACS (2003) z amas = & 1 A = (1 κ ) $ % 0 0# & cos2φ! γ $ 1 % sin 2φ sin 2φ #! cos2φ σ a = 1848 ± 166 km s -1 The convergence κ has a magnification action on the light rays : the image conserves the shape of the source, but with a different size. The shear induces an anisotropy with intensity γ and orientation ϕ. Deep HST image t int = 13.2 hours

Abell 1689 HST ACS Reconstruction of the mass distribution via the gravitational distorsions Shear γ as a function of the convergence κ Seitz & Schneider, 1997, A&A, 318, 687 a field very active

6 Abell 1689 HST ACS Reconstruction of the mass distribution via the gravitational distorsions Shear γ as a function of the convergence κ Seitz & Schneider, 1997, A&A, 318, 687 a field very active since ~ 1995 with Kaiser, Kneib, Bartelmann, and many others Abell 1689 HST ACS (2003) z amas = σ a = 1848 ± 166 km s -1 The distribution of arcs and arclets provides us with a very robust estimator of the total mass : best evidence for dark matter Since 1979 the phenomenon of gravitational lenses is the subject of intense research activities, both theoretical and observational, which have created a new tool for the study of the whole Universe, from nearby planets to the most distant galaxies Deep HST image t int = 13.2 hours

HE1104-1805 H1413+117 critical curves caustics The local properties of

matrix : A β / θ A Horseshoe Einstein Ring from Hubble PG1115+080

jacobian : critical curves and caustics.

7 HE H critical curves caustics The local properties of the application source plane lens plane are described by its jacobian matrix : A β / θ A Horseshoe Einstein Ring from Hubble PG B The locus of a point where A cannot be locally inverted, zero jacobian : critical curves and caustics. LRG was discovered in 2007 in data from the Sloan Digital Sky Survey (SDSS). This image is a follow-up observation taken with the HST WFC3 (NASA/ESA) 1 April 2012 : gravitational lensing effect by a black hole of 1 m J 1 April 2012 : Matterhorn, Zermatt, Switzerland

Usefulness of gravitational lenses European Southern Observatory Paranal - Chili Direct determination of the total mass

and Ω Λ Study of mass distribution of dark matter : - in galaxies - in clusters of galaxies - in large scale structures

Telescope HST NASA/ESA STS 103 19-27 Dec 1999 QSO HE 1104-1805 ESO-MPI 2.2-m IRAC J Courbin et al.

8 Usefulness of gravitational lenses European Southern Observatory Paranal - Chili Direct determination of the total mass of the lensing galaxy Direct determination of cosmological parameters : - Hubble constant H 0 - density parameters Ω m and Ω Λ Study of mass distribution of dark matter : - in galaxies - in clusters of galaxies - in large scale structures Natural telescopes for the observations of very distant objects at very high redshifts Earth and HST Hubble Space Telescope HST NASA/ESA STS Dec 1999 QSO HE ESO-MPI 2.2-m IRAC J Courbin et al., 1998, ApJ, 330, 57 Δ(A,B) = 3.19 z source = 2.32 z lens = 0.73 Observations 0.7 After deconvolution 0.3 The deconvolution provides an essential step

9 Hubble constant estimates from 1927 on The Hubble constant values, from 1927 on Hubble constant estimates from 1927 on, Georges Lemaître 1927 Hubble constant estimates from 1970 on, de Vaucouleurs H 0 = 100 km s -1 Mpc -1 «Un univers homogène de masse constante et de rayon croissant, rendant compte de la vitesse radiale des nébuleuses extra-galactiques» in Georges Lemaître, 1927, Annales de la Société scientifique de Bruxelles, Série A, t. XLVII, avril 1927, pp H 0 = 625 km s -1 Mpc -1 data from Strömberg (1925) Sandage & Tammann H 0 = 50 km s -1 Mpc -1 Freedman et al. (2001) H 0 = 72 ± 7 km s -1 Mpc -1 Sandage et al. (2008) H 0 = 62.3 ± 4.0 km s -1 Mpc -1 Riess et al. (2009) H 0 = 74.2 ± 3.6 km s -1 Mpc -1 Significantly more resources (telescope time, HST Key program, FTE) have so far been allocated to Cepheids and SNIa, when compared with strong gravitational lensing of quasars

10 Workshop on the Hubble Constant The Hubble Constant: Current and Future Challenges Kavli Institute for Particle Astrophysics and Cosmology SLAC, Stanford University, February 6-8, 2012 Questions addressed included : What are the main limitations in measuring H_0? How do we overcome them? Which of the many approaches need to be pursued now? Five broad categories of methods: (1) Cepheids and TRGB (2) (2) Secondary distance indicators including SN Ia, TF and SBF (3) Masers (4) Gravitational lens time delays (5) CMB, BAO and SZ Essential to get direct determination of the H 0 value with an uncertainty closer to 1 % than to 10 % necessity to use all available methods gravitational lensing and time delays The Hubble constant from gravitational lenses and time delays obs Time delay between two different light paths with different lengths * * * * Intrinsic QSO light variations time delay Δτ

11 Time delay the travel time of a photon (Refsdal 1964, 1966) t( θ ) = (1+ z d ) c D d D s & 1 D ds ' ( 2 ( θ β ) 2 ψ( ) θ ) * + = t + t geom grav Measure of the time delay in radio QSO Haarsma et al., 1997, ApJ, 479, 102 The geometric term t geom represents the time delay induced by the longer light path followed by the deflected photons. The gravitational term t grav represents the time delay due to the relativistic time dilation induced by the gravitational field of the deflector. The term in front of the brackets ensures that the measured quantities correspond to the time delay as measured by the observer. intrinsic variations time delay Δτ H 0 Visible: Δτ = 417 ± 3 days H 0 via QSO Model : redshifts, positions, magnitudes, mass profile H ' σ ' 1.1 $ v $ yr = 98 11% % km s Mpc km s Δτ BA & # & # Observations : σ v (lens) = 279 ± 12 km s -1 Δτ BA = 417 ± 3 days H 0 = 67 ± 8 km s -1 Mpc -1 Some gravitational lenses need fine tuning for H 0 determination Falco et al. 1997, ApJ, 484, 70

H 0 via photometric monitoring for QSO RX 0911+05 H 0 via photometric monitoring for QSO RX 0911+05 17 Burud et al., 2003 17 Burud et al.

0.7689 complicates the gravitational potential Kneib, Cohen, Hjorth, 2000, ApJ, 544, L35 COSMOGRAIL COSmological MOnitoring of GRAvItational Lenses Goal : production of 30 time delays over the next

12 H 0 via photometric monitoring for QSO RX H 0 via photometric monitoring for QSO RX Burud et al., Burud et al., 2003 Δτ AB = 146 days Δτ AB = 146 days H 0 = 74 ± 9 km s -1 Mpc -1 H 0 = 74 ± 9 km s -1 Mpc -1 QSO H 0 via QSO RX The presence of a cluster of galaxies at the same redshift as the lens z = complicates the gravitational potential Kneib, Cohen, Hjorth, 2000, ApJ, 544, L35 COSMOGRAIL COSmological MOnitoring of GRAvItational Lenses Goal : production of 30 time delays over the next few years For the photometric monitoring 1-2 m telescopes : Euler Swiss telescope, La Silla, Chile Mercator Belgian-Swiss telescope, La Palma, Canary Islands Maïdanak telescope, Uzbekistan Manchester Robotic telescope, La Palma, Canary Islands Himalayan Chandra telescope, Bangalore, India Hoher Liste, Bonn, Germany For high-resolution photometry and spectroscopy : ESO-VLT, KECK, GEMINI 8-10 m telescopes Hubble Space Telescope NASA/ESA Deconvolution (images and spectra) whenever useful

Observations Till 2004, no organized long-term program for acquisition of time-delay data WFI J2033-4723 In collaboration with C.S. Kochanek, C. Morgan, M.E.

India B To fully exploit the potential of gravitational lensing, need to reduce the uncertainties of measured time delays COSMOGRAIL C Tewes et al.

Hainline (OSU & USNA) a quasar with disturbing microlensing events RXS J1131-1231 Lens with 4 images, z s = 0.66, z l = 0.29, ring θ E = 1.

13 Observations Till 2004, no organized long-term program for acquisition of time-delay data WFI J In collaboration with C.S. Kochanek, C. Morgan, M.E. Eyler, and E.E. Falco Keck Gemini Hawaii La Palma Spain EPFL Maidanak Ouzbekistan A1+A2 Paranal La Silla Cerro Tololo Chili Himalayan Chandra Telescope India B To fully exploit the potential of gravitational lensing, need to reduce the uncertainties of measured time delays COSMOGRAIL C Tewes et al. 2012, in prep. A B J In collaboration with C.S. Kochanek, C. Morgan, L. Hainline (OSU & USNA) a quasar with disturbing microlensing events RXS J Lens with 4 images, z s = 0.66, z l = 0.29, ring θ E = 1.8 (~305 ) raw image pixel = 0.34 seeing = 1.0 Observations : 8 seasons Euler (01/04-07/11), 1pt / 5j a quasar with gentle microlensing events deconvolved image pixel = 0.17 resol = 0.34 Tewes et al. 2012, in prep. but a very difficult case due to short time delays

Euler telescope RXS J1131-1231 RXS J1131-1231 A B C HST ACS a very difficult case due to short time

over a few seasons raw image pixel = 0.34 seeing = 1.0 Lens with 4 images, z s = 1.69, z l = 0.

14 Euler telescope RXS J RXS J A B C HST ACS a very difficult case due to short time delays and microlensing D Light curves from Euler, Smarts, Mercator 3320 images from 630 epochs Tewes et al. 2012, in prep. RXS J HE strong microlensing events can mimic spurious time delays when determined over a few seasons raw image pixel = 0.34 seeing = 1.0 Lens with 4 images, z s = 1.69, z l = 0.45, separation = 2.6 one clear Einstein ring connecting all four images about 10 galaxies within 40 Swiss Euler telescope La Silla ESO deconvolved image pixel = 0.17 resol = 0.34 Tewes et al. 2012, in prep.

HE 0435-1223 Time delay from gravitational lensing Time delay between the two images A and B : H 0-1 A B C D time delay from photometric survey redshift from VLT-Keck spectroscopy astrometry from HST

Step 1 : form of the lensing potential (Hernquist for stars + NFW for DM) Step 2a: MC integration of 3D spherical Jeans equs 2b: lens models 2c: minimize dyn & lensing χ 2 Step 3 : estimate H 0

15 HE Time delay from gravitational lensing Time delay between the two images A and B : H 0-1 A B C D time delay from photometric survey redshift from VLT-Keck spectroscopy astrometry from HST images lens potentiel from models Tewes et al. 2012, in prep. Step 1 : form of the lensing potential (Hernquist for stars + NFW for DM) Step 2a: MC integration of 3D spherical Jeans equs 2b: lens models 2c: minimize dyn & lensing χ 2 Step 3 : estimate H 0 (slope of mass profile from model and/or observations) Status in 2004 : The Hubble constant from quasar time delays! Status in 2009 : The Hubble constant from quasar time delays! HST KP : H 0 = 72 ± 8 km s -1 Mpc -1 HST KP : H 0 = 74.2 ± 3.6 km s -1 Mpc -1 Lensing : H 0 = 61 ± 7 km s -1 Mpc -1 Direct method, known physics Lensing : H 0 = 63.4 ± 8.4 km s -1 Mpc gravitational lenses H 0 = 61 ± 7 km s -1 Mpc time delays H 0 = 63.4 ± 8.4 km s -1 Mpc -1

16 Microlensing phenomenon of a QSO First cases of quasars not lensed by foreground galaxies but playing the role of gravitational lenses on background galaxies The disruptive action of the lensing galaxy splits the single image of the quasar into two or more componants Search in 22,298 SDSS spectra QSO A The selection was carried out in searching, in each of the 22,298 SDSS QSO spectra, for at least four emission lines, all four at a redshift beyond the redshift of the foreground QSO. QSO The lensing nature was confirmed from Keck imaging and spectroscopy. µ = dω dω i s = magnification QSO B Further confirmation was acquired from HST/ WFC3 imaging in the F475W and F814W filters. Courbin etal A&A 540 A36

magnification s First case of lensing quasar observed by EPFL (PR in March 2012) galaxy B

17 The disruptive action of the lensing quasar splits the single image of the galaxy into two or more componants LASTRO EPFL Press Release on 8 March 2012 galaxy A QSO dωi µ = dω = magnification s First case of lensing quasar observed by EPFL (PR in March 2012) galaxy B Courbin(etal.(2012(A&A((540(A36( L'École d'athènes de Raphaël ( ) EUCLID EPFL - GM 68 Musée du Vatican à Rome

Légende 1 : Zénon de Citium ou Zénon d'élée? 2 : Épicure 3 : Frédéric II de Mantoue? 4 : Boèce ou Anaximandre ou Empédocle? 5 : Averroès 6 : Pythagore 7 : Alcibiade ou Alexandre le Grand?

12 : Socrate 13 : Héraclite (sous les traits de Michel-Ange) 14 : Platon tenant le Timée (sous les traits de Léonard de Vinci) 15 : Aristote tenant l Éthique 16 : Diogène de Sinope 17 :

20 : Ptolémée R : Raphaël en Apelle EPFL - GM 69 Selected by ESA on 4 Oct 2011 for launch in 2019 unknown 1) Ω b baryonic matter (attractive) 2) Ω CDM dark matter (attractive) 3) Ω Λ dark

quantities whose nature should revolutionise both physics and our understanding of the Universe dark matter and dark energy Cosmic structure grew from gravitational instability of tiny

18 Légende 1 : Zénon de Citium ou Zénon d'élée? 2 : Épicure 3 : Frédéric II de Mantoue? 4 : Boèce ou Anaximandre ou Empédocle? 5 : Averroès 6 : Pythagore 7 : Alcibiade ou Alexandre le Grand? 8 : Antisthène ou Xénophon? 9 : Hypatie ou Francesco Maria Ier della Rovere? 10 : Eschine ou Xénophon? 11 : Parménide? 12 : Socrate 13 : Héraclite (sous les traits de Michel-Ange) 14 : Platon tenant le Timée (sous les traits de Léonard de Vinci) 15 : Aristote tenant l Éthique 16 : Diogène de Sinope 17 : Plotin? 18 : Euclide ou Archimède entouré d'étudiants (sous les traits de Bramante)? 19 : Strabon ou Zoroastre? 20 : Ptolémée R : Raphaël en Apelle EPFL - GM 69 Selected by ESA on 4 Oct 2011 for launch in 2019 unknown 1) Ω b baryonic matter (attractive) 2) Ω CDM dark matter (attractive) 3) Ω Λ dark energy (repulsive) known Ω CDM Ω b Ω Λ unknown 73 % Dark Energy 23 % Cold Dark Matter 4 % Atoms A very successful model, based on solid observational grounds, but with two unknown quantities whose nature should revolutionise both physics and our understanding of the Universe dark matter and dark energy Cosmic structure grew from gravitational instability of tiny pertubations that reached macroscopic scales during an early inflation period without dark energy with dark energy Dark matter shapes visible matter in a way that reflects the nature of dark energy. How galaxies are distributed in a Universe with no dark energy (left) would differ measurably from one in which dark energy is significant (right).!

Deflection of light rays, emitted by distant galaxies, while crossing the Universe induces of phenomenon called weak gravitational lensing Euclid : optical/near-infrared survey covering 15,000 deg

shape & distance image colombi IAP tomography! The 2 instruments VIS (R+I+Z) + NISP (Y, J, H) will provide shape & distance for about 1.

19 Deflection of light rays, emitted by distant galaxies, while crossing the Universe induces of phenomenon called weak gravitational lensing Euclid : optical/near-infrared survey covering 15,000 deg jhgjhgjhgjg 2 + two 20 deg 2 deep fields optimized for two independent primary cosmological probes Weak Gravitational Lensing (WL) and Baryonic Acoustic Oscillations (BAOs) image colombi IAP! shape & distance image colombi IAP tomography! The 2 instruments VIS (R+I+Z) + NISP (Y, J, H) will provide shape & distance for about 1.5 billion galaxies WL : small systematic alignments in the random orientations of galaxies as a function of their distances BAO : wiggle patterns in the clustering of galaxies : a standard ruler to assess the evolution of the Universe bkhbkhbkhb The shape of a galaxy at ~ 1% accuracy Sarah Bridle Great08

20 Ivan R. King HAPPY BIRTHDAY Thanks you!

PRINCIPLES AND APPLICATIONS OF GRAVITATIONAL LENSING. The precursors of XVIII et XIX centuries. 2 G M r. v e

Cours de Cosmologie observationnelle Master 010-011 EPFL 18 May 011 PRINCIPLES AND APPLICATIONS OF GRAVITATIONAL LENSING Georges Meylan Laboratoire d Astrophysique Ecole Polytechnique Fédérale de Lausanne