Redshifts of Lyman break galaxies and AGN at z3

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Redshifts of Lyman break galaxies and AGN at z3

• Harold Francke
• U. Chile - Yale
• Prof. Eric Gawiser

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Motivation

• Learn about galaxy formation at z3
• How do LBG, LAE, AGN, DLA spatially correlate
  with each other? ? need redshifts!
• We also have AGN detected with x-rays!
• What was the SFR in the past?
• UV emission (Lya emission and continuum) of
  galaxies correlates with star formation
• ? lets use the EQW of the Lya emission lines
  and the photometry to set constrains!
• Grand Unification says AGN(irritated) normal
  galaxy
• Test it by comparing the above mentioned
  properties

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Raw IMACS data mask image, 2-d spectrum
Guillermo Blanc
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COSMOS Pipeline 2-d spectrum, after biasflat
Guillermo Blanc
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COSMOS Pipeline after biasflat, after subsky
Guillermo Blanc
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EXAMPLES OF OBJECTSR22.8, z3.38 LBG in E-CDFS
with strong Lyman alpha emission/absorption
and numerous chemical absorption features (6 hr
IMACS exposure)(SiII 1260, OI/SiII 1303, CII
1334, SiIV 1394,1402, SiII 1527, CIV 1549, FeII
1608)
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R25.7, z3.084 LAE in E-CDFSwith EWgt300Å,
Wgt75Å, and apparent detection of continuum past
6400Å (6 hr IMACS exposure)
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R24.5, z3.24 LBG in E-HDFSredshift from Lyman
? emissioncontinuum detected but quite noisy
(2.5 hr IMACS exposure)
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R24.3, z3.16 AGN in E-HDFSBroad emission lines
from Lyman ? and CIVLow-luminosity Type I AGN
selected through UVR colors (2.5 hr exposure)
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Typical S/N sourceLBG in E-HDFS, R24.6,
z3.2typical problem skylines CR residuals
can appear as em. lines!
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Low S/N spectrumLBG in E-HDFS, R25.4, z3.22,
only the Lya emission can be seen (but you can
measure a Lya decrement!)
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Artifacts in the spectra
Scratches
Holes, sometimes create fake emission lines
Spectra with negative parts
Catastrophic failures. (just a few)
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Preliminary Results (from E-HDFS)
From the group of 57 spectra with no redshift
determination yet, we may be able to still get
redshifts for 50 of them, raising the number of
objects to 45!
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Redshift and color distribution
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Future Work

• Extract all the spectra
• More fields CDFS, CW1255, SDSS1030
• VIMOS will add 100 LBG spectra more
• Get all the redshiftsEW we can!
• Do the actual science!
• Get SFR from Ly? and continuum
• compare them
• Get cosmic SFR density _at_ z3
• Measure clustering length of LBG
• Determine bias parameter, dark matter halos
• Use redshift distribution and angular clustering
  to measure clustering length independently.
• AGN-LBG cross-correlation