D. Falceta Goncalves - USP

astro.iag.usp.br

D. Falceta Goncalves - USP

Spectra of distant dwarf galaxiesand the probe of galactic mass loss:a science case for MOSAIC/ELTD Falceta-GonçalvesEACH – Universidade de São PauloG. Lanfranchi & A. CaproniUniv. Cruzeiro do SulMOSAIC Workshop – IAG-USP – Feb 1 st 2013D. Falceta-Gonçalves, G. Lanfrachi & A. Caproni


Metal enrichment of the IGM at high redshiftsIntroductionThe Science Case for MOSAIC-EELT presented in this talk is mainly basedon two major topics:(1) the properties of the intergalactic medium (IGM), and(2) the formation of galaxies and their evolutionBoth, mostly targeted at the early evolutionary stages of the Universe.The current standard Cosmology (Λ-CDM) predicts:• the Big Bang origin followed by fast expansion, cooling and evolution ofprimordial density fluctuations• the formation of dark mattter dominated structures in a bottom-uphierarchy.• the formation of galaxies as the IGM dynamically evolves over these DMhaloes.MOSAIC Workshop – IAG-USP – Feb 1 st 2013D. Falceta-Gonçalves, G. Lanfrachi & A. Caproni


Metal enrichment of the IGM at high redshiftsIntroductionDark Matter HaloesPress-Schechter theoryz=0z=9MOSAIC Workshop – IAG-USP – Feb 1 st 2013D. Falceta-Gonçalves, G. Lanfrachi & A. Caproni


Metal enrichment of the IGM at high redshiftsIntroductionVia Lactea Project (N-Body simulation)MOSAIC Workshop – IAG-USP – Feb 1 st 2013D. Falceta-Gonçalves, G. Lanfrachi & A. Caproni


Metal enrichment of the IGM at high redshiftsIntroductionThe further formation of a galaxy following the DM halo is definitely nottrivialIt is known that 10 12 h -1 M dark matter haloes are more efficient inincreasing the luminosity-to-mass ratio (Yang, Mo & van den Bosch, 2003;Eke et al., 2004).Possibly, the larger haloes are less efficient due to collapsing timescales,while lower mass haloes due to strong feedback;In any case, dwarf galaxies are supposed to be formed much earlier thanthe massive counterpart and dominate the population of the Universe athigh-z.MOSAIC Workshop – IAG-USP – Feb 1 st 2013D. Falceta-Gonçalves, G. Lanfrachi & A. Caproni


Metal enrichment of the IGM at high redshiftsDwarf GalaxiesThe classical dwarfs are characterized by• low luminosities (-18 < M B < -9), low masses (10 6 M – 10 9 M ),• small sizes (R c = 0,09 - 0,9 kpc), and,• normally, a low metal content (from ~ 0.1 to 0.001 solar) - made of mostlyprimordial materialEven though abundant, they are yet poorly known and many might still be descovered(µ B = 23 mag arcsec -2 ).MOSAIC Workshop – IAG-USP – Feb 1 st 2013D. Falceta-Gonçalves, G. Lanfrachi & A. Caproni


Metal enrichment of the IGM at high redshiftsDwarf GalaxiesThe formation and evolution of local dSph galaxies are still matter of debate.They could also be formed as suggested by ΛCDM scenario (Revaz et al.2010, Salvadori et al. 2010, Calura et al. 2009) – SFHs and chemicalproperties.Or by monolithic collapse (Marcolini et al. 2006, Fenner et al. 2006, Lanfanchi &Matteucci 2003, 2004) - abundance ratios, mass and SMD.Search for high z counterparts is KEYTheir evolution is strickly related to FEEDBACK, i.e. to mass and energy loss tothe IGMMOSAIC Workshop – IAG-USP – Feb 1 st 2013D. Falceta-Gonçalves, G. Lanfrachi & A. Caproni


Metal enrichment of the IGM at high redshiftsDwarf GalaxiesHydrodynamical numerical simulations of the baryonic component of dwarfgalaxies reveal that [Ruiz et al 2013, da Silva et al 2013]:MOSAIC Workshop – IAG-USP – Feb 1 st 2013D. Falceta-Gonçalves, G. Lanfrachi & A. Caproni


Metal enrichment of the IGM at high redshiftsDwarf Galaxies• mass loss rates > 10 -3 M /yr occur for typical SFRs,• galactic winds are selective, ~ 40% of the mass loss is from heated/enrichedmaterialMOSAIC Workshop – IAG-USP – Feb 1 st 2013D. Falceta-Gonçalves, G. Lanfrachi & A. Caproni


Metal enrichment of the IGM at high redshiftsIntergalactic Mediumin the 1960s , Gunn & Peterson observed slight Ly α absorption in the spectra ofrecently discovered quasarsThe neutral column densities of these absorption systems range from 10 12 to 10 22cm −2 .Many of these hydrogen absorption systems also show absorption lines frommetals like carbon, silicon, nitrogen, oxygen, magnesium, iron, and others [e.g.Songaila, 2001]The origin of these metals in absorptionsystems is an open issueMOSAIC Workshop – IAG-USP – Feb 1 st 2013D. Falceta-Gonçalves, G. Lanfrachi & A. Caproni


Metal enrichment of the IGM at high redshiftsIntergalactic MediumCoupling between galactic formation and the IGM at high-z“final frontier of cosmology” [e.g. Bromm & Loeb, 2007]MOSAIC Workshop – IAG-USP – Feb 1 st 2013D. Falceta-Gonçalves, G. Lanfrachi & A. Caproni


Metal enrichment of the IGM at high redshiftsIntergalactic Medium• Our simulations suggest that remaining gas content in dSph after ~0.5 Gyrhave:– Mean number densities between 0.1 and 1.0 cm -3 ;– Column densities of H between 10 18 and 10 21 cm -2 ;– Temperatures between 10 3 and 10 5 K;• How to probe spectroscopically such a scenario of IGM enrichment by dwarfgalaxies?MOSAIC Workshop – IAG-USP – Feb 1 st 2013D. Falceta-Gonçalves, G. Lanfrachi & A. Caproni


Metal enrichment of the IGM at high redshiftsMOSAIC – EELTColumn densityColumn density distribution functionf(N) ≡ number of absortion-line systems per unitredshift path per unity of column densityMOSAIC Workshop – IAG-USP – Feb 1 st 2013D. Falceta-Gonçalves, G. Lanfrachi & A. Caproni


Metal enrichment of the IGM at high redshiftsMOSAIC – EELT• Spectra of C IV and Si IV doublets from HIRES spectrographon Keck I [Songaila et al. 1998];• Resolution of R = 37000;• Total exposure times from 3.3 hr to ~10 hr (individualexposures taking ~40 mins).MOSAIC Workshop – IAG-USP – Feb 1 st 2013D. Falceta-Gonçalves, G. Lanfrachi & A. Caproni


Metal enrichment of the IGM at high redshiftsMOSAIC – EELT• Madau, Ferrara & Rees (2001):"The well established existence of heavy elements like carbon, nitrogen,and silicon in the Lyα forest clouds at z ~ 3 - 3.5 may be the bestevidence for such an early episode of pregalactic star formation. Thedetection of weak but measurable C IV and S IV absorption lines in cloudswith H I column densities as low as 10 14.5 cm -2 implies a minimumuniversal metallicity relative to solar in the range [3.2] to [2.5] at z ~ 3 -3.5 (Songaila 1997)."MOSAIC Workshop – IAG-USP – Feb 1 st 2013D. Falceta-Gonçalves, G. Lanfrachi & A. Caproni


Metal enrichment of the IGM at high redshiftsMOSAIC – EELTρ Z>3 ~10 5 M Mpc -3 Ω (C iv) ~ 5 × 10 −8 , [C/H] = −2.8 (Schaye et al. 2003MOSAIC Workshop – IAG-USP – Feb 1 st 2013D. Falceta-Gonçalves, G. Lanfrachi & A. Caproni


Metal enrichment of the IGM at high redshiftsMOSAIC – EELT• Taking advantage of E-ELT + MOSAIC capabilities:– Substantial reduction on exposure times (t ∝ D -2 );– OR improving the detection rate of low-column density systems (e.g., CIVcolumn densities


Metal enrichment of the IGM at high redshiftsMOSAIC – EELT• Summary– E-ELT MOSAIC would provide high definition (multi LOS per object, e.g.)and high resolution spectra (R ~ 20k) of just formed galaxies (mostlydwarfs);– Possible to detect gas with N H < 10 18 at z>5, basically the limit for δ~1(Lyman alpha blobs)• The smallest CIV column densities detected with 8-10 m class telescopes are N(CIV)~10 11.5cm −2 (S/N ~100).– Objects with fluxes of order of 10 -19 -10 -18 erg/s/cm 2 /” 2 ;– Probe metallicity at z>5 (when were metals thrown into the IGM?);– Solve basic theoretical issues regarding galactic evolution:• Star formation history• Metal rich or metal poor windsMOSAIC Workshop – IAG-USP – Feb 1 st 2013D. Falceta-Gonçalves, G. Lanfrachi & A. Caproni


Spectra of distant dwarf galaxiesand the probe of galactic mass loss:a science goal for MOSAIC/ELTD Falceta-GonçalvesEACH – Universidade de São PauloG. Lanfranchi & A. CaproniUniv. Cruzeiro do SulMOSAIC Workshop – IAG-USP – Feb 1 st 2013D. Falceta-Gonçalves, G. Lanfrachi & A. Caproni

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