Astrophysics and Cosmology Seminar
The build-up of stellar mass in primeval galaxies
Dr. Lukas Furtak
BGU
Abstract
Early star-forming galaxies at redshifts z>6 in the epoch of cosmic reionization are at the frontier of observability with the current instrumentation and represent the primeval states of present-day galaxies. The galaxy stellar mass function (GSMF) at z~6-9 is therefore a robust and crucial tool to study the build-up of stellar mass in the Universe and provides the tightest constraints on cosmological simulations.
These high-redshift galaxies are among the faintest objects observed to date and thus particularly hard to observe in blank fields. Strong gravitational lensing by massive galaxy clusters however allows to probe z>6 galaxies down to 10⁶ solar masses, providing valuable constraints on the very low-mass end of the mass function. In my presentation I will give and overview of high-redshift galaxy studies using gravitational lensing and present our recent work on the low-mass end of the galaxy stellar mass function at z~6-7 using the strong lensing Hubble Frontier Fields clusters. I will discuss these results regarding strong lensing and SED-fitting uncertainties in order to assess what is believable in the resulting mass function regarding these uncertainties and present the methods we have developed to overcome these limitations.
These high-redshift galaxies are among the faintest objects observed to date and thus particularly hard to observe in blank fields. Strong gravitational lensing by massive galaxy clusters however allows to probe z>6 galaxies down to 10⁶ solar masses, providing valuable constraints on the very low-mass end of the mass function. In my presentation I will give and overview of high-redshift galaxy studies using gravitational lensing and present our recent work on the low-mass end of the galaxy stellar mass function at z~6-7 using the strong lensing Hubble Frontier Fields clusters. I will discuss these results regarding strong lensing and SED-fitting uncertainties in order to assess what is believable in the resulting mass function regarding these uncertainties and present the methods we have developed to overcome these limitations.