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Research Areas

Research Areas. Photometric redshifts Cosmology & instrumentation Galaxy Evolution Stellar explosions. Christian Wolf (Oxford). rms 0.006. rms 0.008 7%-20% outlier. Wolf 2001. QE (%). λ / nm. Photometric Redshifts: Past. COMBO-17 Many narrow bands Template-based classification

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Research Areas

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  1. Research Areas • Photometric redshifts • Cosmology & instrumentation • Galaxy Evolution • Stellar explosions Christian Wolf (Oxford)

  2. rms 0.006 rms 0.008 7%-20%outlier Wolf 2001 QE (%) λ/ nm Photometric Redshifts: Past • COMBO-17 • Many narrow bands • Template-based classification • Classes galaxy, star, qso, wd • Reaches z/(1+z) < 0.01 • Accurate rest-frame SED(e.g. old red vs. dusty red)

  3. Training sample Estimation sample Photometric Redshifts: Future • Uses • Select targets for spectroscopy: BAO surveys, galaxy evolution • Very large photo-z surveys:BAO & gravitational lensing • Technique • pi(z|colour) from N(z|colour) in spectroscopic training sample • Critical issues • Spectroscopic completeness • Redshift bias & outlier risk Abdalla et al. 2007

  4. z y x P(k=2 Mpc-1) 2 1 best Cosmology: Past • COMBO-17 redshifts feeding 3D lensing analyses: • Clusters in projection • Dark matter P(k) evolution • Highest-resolution dark matter map in cluster complex AAS Press Conference: The highest resolution Dark Matter map of one of the largest areas ever imaged by the Hubble Space Telescope.

  5. “eXtreme Multiobject Spectrograph” Durham, IAA, MPIA, Wolf & ICG? Specs 4000 slits over 1 at CA 3.5m 150 nm spectral range per shot requires photo-z pre-selection Surveys 5 million redshifts per year Growth of structure, BAO Galaxy evolution at z~0.4..0.8 Photo-z calibration to I<23 mag “SIDE” Multiobject Spectrograph IAA, LBNL, UNAM, … Wolf: leading science case Specs 1000 fibers, 0.1 (10.4m GTC?) 600-1400 nm range, beam split, R~4000, peak QE 25% @ 900 nm Surveys “SDSS” @ z~1, 300-700 nm @ rest Galaxy evolution from fossil records Deep(!) photo-z calibration Low-cost wide-field spectrograph, Content et al. 2008 Cosmology & Instrumentation: Future

  6. Hopkins et al. 2006 Koopmann & Kenney 2004 Kenney et al. 2008 Bamford et al. 2008, Galaxy Zoo Galaxy Evolution: Past • COMBO-17 covers redshift 0..1 • SF decline *not* driven by mergers • Dusty red galaxies = red spirals • Slow quenching of star formation, *not* driven by mergers or starburst • Cosmic double downsizing: internal (AGN) feedback plus environment? E Sp S0 frag Joint press release 2008 ICG, Nottingham, Oxford

  7. Hopkins et al. 2006 Galaxy Evolution: Future • Are S0s made from present spirals? • Disk fading, light profiles, central SF • Outside-in truncation of SF disk, dependence on cluster? • Cluster infall time scales from SFH templates in fossil records • Massive GTC key survey? SIDE @ z=1 • Complementary to: In-situ SFR • UV, HII, FIR, Radio from high-mass stars • Extinction+completeness correction • Fossil record: full spectral fitting & stellar population decomposition • From stars of all masses • Solves for extinction, metallicity • Stellar mass build-up over z = 1..10 • 30-100,000 galaxies with >1010 M • Feasibility study: • Wolf & Maraston, Thomas, Tojeiro (ICG), Montero-Dorta, Prada (IAA)

  8. Stellar Explosions: Past • Host galaxies SNe II : L-GRBs • If GRB Z* cut-off, then solar • Cosmic SFR : SNR history • SN Ia delay time 0-4 Gyr • Archival event search • GALEX UV flash before SN II  red giant progenitor • Radio: BBC, SWR, …

  9. Hamuy et al. 1993/5 Stellar Explosions: Future • Ages & Z* of SN subtypes • Links to progenitor evolution • Galaxy proxy, residual trend • SN Ia light curves: 3-p family • Host galaxy age, dust & Z*? • Cosmic calibration drift? • Early light curves & flashes • Stacking, short cadence, SDSS, PTF, Calan 2010+ • Explosion conditions Conley et al. 2008

  10. Fit into ICG • Support cosmological interests with photo-z expertise: • Critical: precision, completeness, control of systematics • Prepare large galaxy formation surveys 2015+: • Stellar mass build-up over first 5 Gyr (with Claudia + Daniel) • SIDE science case coordination, survey simulations (+ Rita) • Work on spiral-to-S0 transformation & cluster infall timescales • With Bob, Rita, Galaxy Zoo, SDSS, COMBO-17… • Work on Supernovae Ia, access to SDSS-II: • Calibration (dark energy, + Bob) • Progenitors and diversity (91bg’s?), role of age, Z* & dust (+ Rita)

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