170 likes | 285 Views
A survey for DLA galaxies with integral field spectroscopy. Lise Christensen ( Ph.D. student, AIP, Postdam) Collaborators: Sebastian Sanchez, Knud Jahnke, Lutz Wisotski, Martin Roth. The survey. Purpose What types of galaxies host DLAs?
E N D
A survey for DLA galaxieswith integral field spectroscopy Lise Christensen ( Ph.D. student, AIP, Postdam) Collaborators: Sebastian Sanchez, Knud Jahnke, Lutz Wisotski, Martin Roth
The survey Purpose • What types of galaxies host DLAs? • Look for emission lines from the galaxies hosting DLAs • DLA lines known from the literature • Emission properties and impact parameters • Main parts: • Low redshift: Search for optical emission lines from known objects • High redshift (z > 2): search for objects with Lyman-a emission somewhere close to the QSO
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 spectrosopy simultaneously No slit-losses Pointing less crucial Spectral resolution independent on spatial sampling and seeing PMAS facts
Movies…. Looping through a cube of Q2233+131, Sub-DLA @ z =3.15
Candidate DLA galaxies High redshift DLAs • 13 DLAs included in the survey (+ 7 sub-DLAs) towards 9 QSOs • 8 good candidates found – but only candidates • Line flux in the range 3-10*10-17erg cm-2 s-1 • Impact parameters from 1 - 4” (10 - 40 kpc)
Results; Line fluxes; Velocities; Metallicities ; Impact parameters
Results; Line fluxes; Velocities; Metallicities ; Impact parameters
Results; Line fluxes ; Velocities; Metallicities ; Impact parameters
Results; Line fluxes ; Velocities; Metallicities ; Impact parameters Exponential fit Scale length 30+/-16 kpc 5+/-2kpc
Conclusions • Follow-up slit spectra needed • Impact parameters consistent with large disks • Fluxes rather large – Lya properties consistent with those of previously identified DLA galaxies • No preference for candidates from high metallicity DLAs • Integral field spectroscopy is suited for the project • With 8-m class telescopes identification of DLA galaxies will be trivial
Identifying emission lines l 16 spectra Emission from QSO Emission line candidate
Results; Flux ; Velocities; Metallicities ; Impact parameters Power-law fit : b/b*=(N(H)/N(H)*)b b*=20+/-4kpc, b=0.22+/-0.18