Investigating the coevolution between SMBHs and galaxies at z~3 etc.

[Speaker 1]
Yuriko Saito
D1, SOKENDAI, Hawaii(supervisor : Masatoshi Imanishi)
Investigating the coevolution between SMBHs and galaxies at z~3
-our first result-
In the local universe, there is a tight correlation between the masses
of super massive black holes (SMBHs) and stars in the spheroidal
components (bulge and elliptical galaxies), suggesting that their formation
is physically closely related. Various models assuming different physical
mechanisms are proposed to explain the observational result at z=0.
Since these models predict different redshift evolution of the
SMBH-spheroid mass ratio, it is important to observationally constrain
the mass ratio at high redshift. As the predicted difference becomes
larger at higher redshift, going to higher redshift is better to distinguish
among these models, but at the same time observational difficulties
increase at higher redshift. By taking into account these factors,
we have concluded that z=3-3.5 is practically the best redshift range.
However, previous studies have mostly been limited to z<2. We have embarked on (1) systematic near-infrared spectroscopy of z=3-3.5 QSOs, to derive the SMBH masses, based on the the Balmer beta emission line width and nearby continuum luminosity, and (2) Subaru LGS-AO near-infrared multi-color imaging observations, to estimate spheroidal stellar masses in the host galaxies of these QSOs. We obtained spectroscopic data for 34 objects, and succeeded to derive BH masses for 24 objects among them. We have also performed Subaru AO imaging observations of 8 QSOs with estimated SMBH masses, and so far completed AO imaging data analysis of J0725. In this talk, I will present our first result of SMBH mass – bulge mass ratio calculated for J0725. [Speaker 2] Shogo Ishikawa M2, SOKENDAI, Mitaka(supervisor : Nobunari Kashikawa) [Title] The clustering properties of star-forming galaxies at z~2 by extremely wide-field survey [Abstract] One of the most critical method to trace the evolution history of galaxies is to compare the mass of dark haloes. Dark halo mass monotonically grows by merging with cosmic time、 so this parameter reflects the growing history of galaxy directly. In recent years, a number of LBGs/LAEs at z>3 are obtained and dark halo masses of z>3 galaxies are revealed.
On the other hand, dark halo masses at z~2 is not so much explored because there are technical difficulties to observe galaxies at z~2. That is why z~2 is known as “redshift-desert”; however, z~2 is also thought to be a important era to study galaxy formation and evolution.
We conducted the wide field survey to obtain star-forming galaxies at z~2, applying so called “BzK selection technique”. In this talk, we report the results of clustering analysis of star-forming galaxies at z~2. Especially, we performed the full HOD analysis of z~2 galaxies the first in the world.