faint galaxies behind Abell 1689

Ultra-Faint Lensed Galaxies Behind Abell 1689: Luminosity Functions and Properites

Presented by: Brian Siana (UC Riverside)

Category: Science Workshops   Duration: 15 minutes   Broadcast date: April 17, 2013

redshift evolution of dust extinction (Naveen Reddy (Hubble Fellow, NOAO))

Using the luminosity ratio to illustrate the extinction, galaxies in redshift 2 are brighter than local galaxies with the same extinction. That's why there is extinction correction when plot the SFR vs redshift.

galaxies in redshift 2 are brighter than the local galaxies with the same extinction or metallicity.

Ly a at z3. Caryl Gronwall 2010

This EW distribution is interesting. Comparing the high L galaxies and the low L galaxies, you can find the same trend as in my paper.

She think there is no evolution of the Luminosity function from redshift 2 to 6, but is this really true? Just based on this plot, we can see that the faint end of luminosity function may be quite the same, but there could be much different in the high L galaxies.  The idea that the most massive galaxies have already formed in redshift 2 but not at redshift 3 is widely accepted. This could be the reason of this plot. 

What is more, it is quite interesting that in my paper Xingxing Huang et al. 2013, there are more galaxies with high EW in the faint end. Maybe this is because that the massive galaxies are formed by less massive galaxies and they are higher metallicity and higher dust extinctions. Then if we check the galaxies higher than redshift 3, massive galaxies have not formed, and there should be more high EW galaxies as discovered in Shim et al. 2013 or other paper.

epoch of massive galaxy assembly

 Perhaps the key result from these early near-IR surveys was that, unexpectedly at the time, at a redshift of z=1 (at which point the Universe was basically half its current age) a large fraction of the most massive galaxies (galaxies containing the same stellar mass as 100 billion stars like our Sun) where already in existence. However, if you push your observations further back in time, out to perhaps a redshift of z=3 (when the Universe was only 15% of its current age), you find that only a small fraction of the massive galaxies we observe locally already existed at this earlier epoch. Consequently, it became clear that the 3.5 billion years of history contained within the redshift interval 1<z<3 constitutes the "epoch of massive galaxy assembly", during which the vast majority of the massive galaxies we observe in the local Universe were formed. The primary motivation for the Ultra Deep Survey was to study this key epoch in the evolution of the Universe.

From http://candels-collaboration.blogspot.com/2012/07/uds-ultra-deep-survey.html

evolution of EW

From R. Smit et al.2013