1 / 29

The connection between galaxies and quasar absorption lines

The connection between galaxies and quasar absorption lines. Lise Christensen. Quasar absorption lines. Ly a forest. Metal lines. LLS. DLA. Types of systems. Ly a forest : N (H I ) < 10 17 cm -2 LLS : 10 17 < N (H I ) < 2*10 20 cm -2

amethyst-reid
Download Presentation

The connection between galaxies and quasar absorption lines

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. The connection between galaxies and quasar absorption lines Lise Christensen

  2. Quasar absorption lines Lya forest Metal lines LLS DLA

  3. Types of systems Lya forest :N(H I) < 1017 cm-2 LLS: 1017 < N(H I) < 2*1020 cm-2 DLA : N(H I) > 2*1020 cm-2 Charlton, 2000

  4. Column density distribution b is roughly =1.5 over 10 decades most mass is contained in high N systems (neutral gas only) Evidence for a steeper slope at DLA column densities Petitjean et al. 1993

  5. Neutral gas density DLA Mass in stars (SDSS) evolution with z ? DLAstars DLAs are reservoirs for galaxy formation? 21 cm observations Rao et al. 2005 Prochaska et al. 2005 Zwaan et al. 2005

  6. Metal lines- from high resolution observations

  7. DLA metallicities Prochaska et al. 2003

  8. What we know about DLAs: • N(H I) as galaxy disks – but are they disks? • Metal enriched – star formation has taken place [M/H] between halo and disk stars Slow evolution • Reservoirs for star formation? • In what type of galaxies do DLAs reside?

  9. Purpose of the integral field spectroscopic survey • What types of galaxies harbor DLAs? • Large disks or small dwarfs? • Understand proto-galaxies • DLA galaxies present an alternative selection to flux limited surveys • Look for emission lines from the galaxies hosting DLAs • SFRs, Impact parameters, and sizes • Main parts: • Low redshift: Search for optical emission lines • High redshift (z > 2): search for Lyman-a emission

  10. Observations are done with: PMAS= Potsdam Multi Aperture Spectrophotometer 16*16 fibres connected to lens array (no loss between fibres) 8”*8” field of view ( in our setup) 3.5 m telescope at Calar Alto, Spain IFS advantages: Imaging and spectroscopy simultaneously No slit-losses Pointing less crucial Spectral resolution independent on spatial sampling and seeing The PMAS instrument

  11. Method

  12. Method d l a

  13. Previous low-z studies: Low-z : ~30 known DLA systems – 14 confirmed DLA galaxies 3C 336, z = 0.927 DLA at z = 0.656 24000 s WFPC2 archive image (Steidel et al 1997)

  14. [O II] at z=0.656 But where is the z=0.656 DLA galaxy? z =0.931 R=24.5 z=0.8908 R=23.5

  15. Abundances PHL 1226 – subDLA at z=0.16 projected distance: 18 kpc (Bergeron et al. 1988) Christensen et al. 2005

  16. Abundances Figure from Pettini et al, 2004 G4: Christensen et al. 2005 DLA metallicities could be biased by gradient compare metallicities from emission and absorption

  17. DLAs at high redshifts (z>2) >500 DLA systems known – 6 confirmed…(3 intervening) Q2233+131, z = 3.3 Sub-DLA at z = 3.15 m~25 Djorgovski et al 1996, Christensen et al. 2004

  18. Visualisation – long slits

  19. Visualisation – narrow bands - cubes l l

  20. Movies Looping through a cube of Q2233+131, Sub-DLA @ z =3.15

  21. Candidate DLA galaxies Results: high-z DLA survey • 14 DLAs (+ 8 sub-DLAs) towards 9 QSOs • 8 good candidates found – but only detected at the 3-4s levels • Line flux in the range 3-10*10-17erg cm-2 s-1 • Impact parameters from 1 - 4” (10 - 40 kpc)

  22. DLA galaxy; Line fluxes; Impact parameters ; masses ; SFRs Red symbols from compilation in Moeller et al. 2002

  23. DLA galaxy; Line fluxes ;Impact parameters; masses ; SFRs Exponential fit Scale length 30+/-16 kpc 5+/-2kpc

  24. DLA galaxy; Line fluxes ;Impact parameters; masses ; SFRs Average predicted impact parameters from simulations +low-z data from Chen et al. 2005

  25. DLA galaxy; Line fluxes ; Impact parameters ;masses ; SFRs This mass is in neutral gas; M(H I) (MW has 3*109 M ) Does this imply that DLA galaxies are L* galaxies? No. This is neutral gas mass only. MW mass ~1011 M (in stars) Numerical simulations by Nagamine et al. 2004 suggest M*/Mgas=3 at z=3 M(DLA gal) = 1010 M ~10% M(MW)

  26. DLA galaxy; Line fluxes ; Impact parameters ; masses ; SFRs Schmidt-Kennicutt law:

  27. DLA galaxy; Line fluxes ; Impact parameters ; masses ;SFRs Luminosity selected galaxies Lilly et al. 1995, Steidel et al. 1999

  28. DLA galaxy; Line fluxes ; Impact parameters; masses ; SFRs Dust obscuration bias? Comoving SFR DLAs: Wolfe et al. 2005, Storrie-Lombardi et al. 2000, Peroux et al 2003, Prochaska et al 2005

  29. Summary • IFS able to identify faint emission lines • independent confirmation is needed • Lya properties consistent with known DLA galaxies • Impact parameters indicate large disks large impact parameters at high and low-z • Disks are massive, but not necessarily luminous • Average SFR consistent with a Schmidt-Kennicutt law assuming radial sizes of 10 kpc • DLAs do not dominate the comoving SFR missing very high N(HI) DLAs in surveys ? 6. DLA metallicities biased by gradients?

More Related