Lyman-α Cosmology with BOSS Julián Bautista University of Utah. Rencontres du Vietnam Cosmology 2015

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1 Lyman-α Cosmology with BOSS Julián Bautista University of Utah Rencontres du Vietnam Cosmology 2015

2 Lyman-α Forest of a Quasar (by Andrew Pontzen) F ( obs )= Observed flux Unabsorbed flux ( obs) 2

3 Lyman-α Forest of a Quasar (by Andrew Pontzen) F ( obs )= Observed flux Unabsorbed flux ( obs) 3

4 Survey of Lyman-α Forests Tracers of matter distribution in the Universe Quasars IGM blog.sdss3.org 4 Earth

5 BOSS Baryon Oscillation Spectroscopic Survey DR quasars at 2 < z <3.5 15% more than DR11 Measuring BAO when the Universe was one fifth of its age BAO Expansion rate Dark Energy BAO scale 5

6 Measuring BAO with forests Quasar redshifts: visual inspection of all targets (Paris++2014) Redshift z Redshift z BAO scale ~150 Mpc Continuum level amount of absorption Compute correlation function (~r) =h i j i Measure the BAO scale 6 r? r k ~r obs [nm] obs [nm] BOSS spectral coverage

7 Lyman-α auto-correlation function DR11 r 2 (r?,r k ) r k j i r? r k [h -1 Mpc] r? [h -1 Mpc] (Delubac, JB, )

8 Lyman-α auto-correlation function r k DR11 (~r) r? (Delubac, JB, ) 8

9 Quasar Lyman-α cross-correlation function DR11 j (Font-Ribera++2014) 9

10 Fitting BAO model BAOfit package with continuum distortion model (Kirkby , Blomqvist ) model (~r, k,? )= cosmo (~r, k,? )+ broadband (~r) k = D H( z)/r d and? = D A( z)/r d [D H ( z)/r d ] fid [D A ( z)/r d ] fid Radial BAO Transverse BAO r k DR11 k Bias 0? r? 10 Redshift-space distortions

11 Tests on Mock Catalogs Log-normal absorption fields 1.0 (JB++2015) Correlation functions Transmission F ( ) DR11 Mocks Wavelength [nm] f [erg s 1 cm 2 Å 1 ] Wavelength [nm] BOSS like spectrua 11 BAO best-fits 100 realizations

12 obs [nm] r k j Lyman-α i r? auto-correlation function Preliminary DR12 r k [h 1 Mpc] r 2 (r?,r k ) r 2 µ r? [h 1 Mpc] JB++ 12 in prep 0 <µ< <µ< <µ< r [h 1 Mpc]

13 obs [nm] i Quasar Lyman-α cross-correlation function Preliminary DR12 r k [h 1 Mpc] r 2 (r?,r k ) r 2 µ <µ<0.5 1 <µ< 0.5 and 0.5 <µ< r? [h 1 Mpc] r [h 1 Mpc] JB++ 13 in prep

14 BAO Results DR11 and DR12 Preliminary 2 Auto-correlation = /( ) / ( ) 2 Cross-correlation = / ( ) 426.4/420 k? = 1.054(32) = 0.973(56) 1.030(26) 1.018(45) k? = 1.050(30) = 0.916(29) 1.042(34) 0.930(36) DR12 Planck 2015 Delubac, JB JB++ in prep

15 Cosmology DR11 Expansion rate Angular distance (Aubourg++2014) 15

16 What is new in DR12 16

17 What is new in DR quasars at 2 < z <3.5 15% more than DR11 17

18 What is new in DR12 Work in progress! - Improved modelling of metal contamination in the forest - New CCD extraction algorithm - Throughput correction (Margala++2015) - Null tests 18

19 What is new in DR12 Work in progress! - Improved modelling of metal contamination 1D Line of sight correlations SiII(1193)/SiII(1190) Lya/SiIII SiIII/SiII(1193) SiIII/SiII(1190) Lya/SiII(1193) Lya/SiII(1190) SiII(1260)/Lya SiII(1260)/SiIII SiII(1260)/SiII(1193) SiII(1260)/SiII(1190) Mock Data (nm) Lyα SiIII SiII SiII SiII Mocks ( WithMet NoMet )[ 10 4 ] / 2 Metal line contaminating the BAO peak Use of metal templates while fitting for BAO 19

20 What is new in DR12 Work in progress! - New CCD extraction algorithm Unbiased estimator of counts More accurate propagation of errors (5% increase) Cleaner mean transmission Less sky residuals 20

21 What is new in DR12 - Throughput correction (Margala++2015) Due to different focal plane configurations between stars and quasars Uncorrected Corrected 21

22 - Null tests Build fake forests Compute correlations What is new in DR12 Expectation Measurement Work in progress! 22

23 What is new in DR12 - Systematics Contributions from sky model, calibration and galactic absorption Work in progress! No significant shift in the BAO peak estimates! 23

24 CONCLUSIONS Lyman-α forest BAO allows us to access expansion at z ~ 2.3 DR12 analysis: 15% more data Robust estimate of astrophysical and instrumental systematics Stay tuned! 24

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26 Large-scale structure of Lyman-α emission intensity (First optical intensity mapping result) Quasar BOSS$ LRG$fiber$$ spectra$ minus$lrgs$ Cross7correla9on$ Cro:,$Miralda7Escude,$Zheng$et$al.$ (2015)$arXiv: $ Quasar&Lya)emission)cross&correla1on:) ))))Shape)=)Lambda)CDM) ))))Amplitude))prop.)to))bias)X)mean)) ))))))))))))))))))))))))intensity)of)lya)emission.) 26