「コロキウム」カテゴリーアーカイブ

clustering properties of z~2 galaxies by extremely wide field galaxy survey etc.

[Speaker1]
Shogo Ishikawa , D1, SOKENDAI, Mitaka(supervisor: Nobunari Kashikawa)
[Title]
clustering properties of z~2 galaxies by extremely wide field galaxy survey

[Speaker2]
Masafusa Onoue , M2, SOKENDAI, Mitaka(supervisor: Nobunari Kashikawa)
[Title]
The Selection Method for Finding High-z Quasar
[Abstract]
In this colloquium, I’d like to start with explaining how to estimate redshift of unknown objects, and why it is important. Then, I will show you the progress of the development of effective quasar selection method that I have been working on.

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

[Speaker1]
Yuriko Saito, D2, SOKENDAI, Mitaka(supervisor: Masatoshi Imanishi)
[Title]
Investigating the coevolution between SMBHs and galaxies at z~3 -error estimate-
[Abstract]
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.

To achieve our goal, we have been carried out both spectroscopic and imaging observations, and obtained 37 spectroscopic data and 9 imaging data of z~3 quasars. We completed to analyze spectroscopic data and obtained BH masses for 28 out of 37 objects.
Now we have started imaging data analysis and obtained preliminary result of SMBH-spheroid mass ratio at z~3 (previous talk).
However, there is too large uncertainty to constrain the mass ratio and it is important to reduce the error.

There are three noise sources that contribute to the total error of SMBH-spheroid mass ratio.
1) BH mass error : BH mass is estimated from the Balmer beta emission line width and AGN luminosity at 5100A. So this error is dominated by line width error (i.e. spectral fitting error) and luminosity error (i.e. S/N ratio at ~5100A), and has been already estimated for 28 objects.
2) Spheroidal luminosity error : spheroidal luminosity is estimated by decomposing AGN and host galaxy radiation by fitting both components.Thus, we should consider the fitting error carefully and try to reduce it.
3) Mass to luminosity ratio (M/L) error : to estimate spheroidal mass,we convert spheroidal luminosity to mass using M/L ratio which is derived from host galaxy color in this study. Therefore, accurate M/L determination and reducing its error is crucial.

In my past talks, I have been presented BH mass estimates, our preliminary results of spheroidal mass estimates and the redshift evolution of SMBH-spheroid mass ratio.
In this talk, I will explain errors that we should care for the accurate mass ratio determination with introducing related papers,and present current progress of error estimate.

[Speaker2]
Anjali John, D3, SOKENDAI, Mitaka(supervisor: Y.Suematsu)
[Title]
Unipolar Appearance and Disappearance of the Sun’s Polar Magnetic Patches

Current progress on the CLASP telescope alignment

[Speaker 1]
GIONO Gabriel, D2, SOKENDAI, Mitaka（supervisor：Suematsu Yoshinori, Katsukawa Yukio, Hara Hirohisa）
[Title]
Current progress on the CLASP telescope alignment.
[Abstract]
The Chromospheric Lyman-Alpha SpectroPolarimeter (CLASP) is a sounding rocket instrument currently under development at NAOJ. CLASP aims to measure for the first time the polarization of the Lyman-Alpha line (121.6nm) emitted from the solar upper-chromosphere and transition region, and derived the magnetic field strength and orientation through the Hanle effect.
CLASP instrument is composed of a classical Cassegrain telescope focusing the light inside an inverse-mount Wadsworth spectrograph. A polarization analyzer is located on both of the two channels, and a rotating half-waveplate is used for the polarization modulation.
As part of CLASP development, both telescope’s primary and secondary mirrors have to be properly align in order to ensure a good image and spectrum quality.
In this colloquium, the current progress on the telescope’s alignment will be presented. As an introduction, the experiment “double-pass” configuration will be explained as well as the basic principle of telescope’s alignment. Then, the measured wavefront error (WFE) and how it was retrieved from the interferences fringes will be shown. Finally, the adjustment estimation on the secondary mirror tilt will be derived by comparing the WFE aberration coefficient to ray-tracing simulations.