Early Science Result from the Japanese Virtual Observatory: AGN and Galaxy Clustering at z = 0.3 to 3.0

We present the result of projected cross correlation analysis of AGNs and galaxies at redshifts from 0.3 to 3.0. The Japanese Virtual Observatory (JVO) was used to obtain the Subaru Suprime-Cam images and UKIDSS catalog data around AGNs. We investigated 1,809 AGNs, which is about ten times larger a sample than that used in previous studies on AGN-galaxy clustering at redshifts larger than 0.6. 90% of the AGN samples are optically-selected AGN from the SDSS and 2dF catalogs. The galaxy samples at low redshift includes many redder objects from UKIDSS survey, while at higher redshift they are mainly blue galaxies from Suprime-Cam. We found significant excess of galaxies around the AGNs at redshifts from 0.3 to 1.8. For the low redshift samples ($z<0.9$), we obtained correlation length of $r_{0} =$5--6 $h^{-1}$Mpc ($\gamma = 1.8$), which indicates that the AGNs at this redshift range reside in a similar environment around typical local galaxies. We also found that AGNs at higher redshift ranges reside in a denser environment than lower redshift AGNs; For $z=1.3 \sim 1.8$ AGNs, the cross correlation length was measured as 11$^{+6}_{-3}$ $h^{-1}$Mpc ($\gamma=1.8$). Considering that our galaxies sample is based on optical observations with Suprime-Cam at the redshift range, it is expected that blue star-forming galaxies comprise the majority of objects that are observed to be clustered around the AGNs. It is successfully demonstrated that the use of the archive through the Virtual Observatory system can provide a powerful tool for investigating the small scale environment of the intermediate redshift AGNs.Comment: accepted to PASJ, 36 pages, 21 figures, this is an accepted versio

Radiometric Model and Inter-Comparison Results of the SGLI-VNR On-Board Calibration

The Second Generation Global Imager (SGLI) on Global Change Observation Mission Climate (GCOM-C) satellite empowers surface and atmospheric measurements related to the carbon cycle and radiation budget, with two radiometers of Visible and Near Infrared Radiometer (SGLI-VNR) and Infrared Scanning Radiometer (SGLI-IRS) that perform a wide-band (380 nm12 m) optical observation not only with as wide as a 11501400 km field of view (FOV), but also with as high as 0.250.5 km resolution. Additionally, polarization and along-track slant view observations are quite characteristic of SGLI. It is important to calibrate radiometers to provide the sensor data records for more than 28 standard products and 23 research products including clouds, aerosols, ocean color, vegetation, snow and ice, and other applications. In this paper, the radiometric model and the first results of on-board calibrations on the SGLI-VNR, which include weekly solar and light-emitting diode (LED) calibration and monthly lunar calibration, will be described. Each calibration data was obtained with corrections, where beta angle correction and avoidance of reflection from multilayer insulation (MLI) were applied for solar calibration; LED temperature correction was performed for LED calibration; and the GIRO (GSICS (Global Space-based Inter-Calibration System) Implementation of the ROLO (RObotic Lunar Observatory) model) model was used for lunar calibration. Results show that the inter-comparison of the relative degradation amount between these three calibrations agreed to within 1% or less