Browsing by Author "Yoshii, Y."

Now showing 1 - 2 of 2
  • No Thumbnail Available
    Item
    REVERBERATION MAPPING OF THE SEYFERT 1 GALAXY NGC7469
    (2014) Peterson, B. M.; Grier, C. J.; Horne, Keith; Pogge, R. W.; Bentz, M. C.; De Rosa, G.; Denney, K. D.; Martini, Paul; Sergeev, S. G.; Kaspi, S.; Minezaki, T.; Zu, Y.; Kochanek, C. S.; Siverd, R. J.; Shappee, B.; Salvo, C. Araya; Beatty, T. G.; Bird, J. C.; Bord, D. J.; Borman, G. A.; Che, X.; Chen, C. -T.; Cohen, S. A.; Dietrich, M.; Doroshenko, V. T.; Drake, T.; Efimov, Yu. S.; Free, N.; Ginsburg, I.; Henderson, C. B.; King, A. L.; Koshida, S.; Mogren, K.; Molina, M.; Mosquera, A. M.; Motohara, K.; Nazarov, S. V.; Okhmat, D. N.; Pejcha, O.; Rafter, S.; Shields, J. C.; Skowron, D. M.; Skowron, J.; Valluri, M.; van Saders, J. L.; Yoshii, Y.
    A large reverberation-mapping study of the Seyfert 1 galaxy NGC7469 has yielded emission-line lags for H beta lambda 4861 and He He II lambda 4686 and a central black hole mass measurement M-BH approximate to 1 x 10(7)M(circle dot) , consistent with previous measurements. A very low level of variability during the monitoring campaign precluded meeting our original goal of recovering velocity-delay maps from the data, but with the new H beta measurement, NGC7469 is no longer an outlier in the relationship between the size of the H beta-emitting broad-line region and the luminosity of the active galactic nucleus. It was necessary to detrend the continuum and H beta and He He II lambda 4686 line light curves and those from archival UV data for different time-series analysis methods to yield consistent results.
  • Thumbnail Image
    Item
    TARdYS: Design and prototype of an exoplanet hunter for TAO using a R6 Echelle grating
    (2019) Rukdee, Surangkhana; Vanzi, Leonardo; Schwab, C.; Flores Cabrales, Mauricio Fabián; Valenzuela Navarro, Álvaro Enrique Hernán; Pember, J.; Zapata, Abner; Motohara, K.; Yoshii, Y.; Tala Pinto, M.
    One limitation in characterizing exoplanet candidates is the availability of infrared, high-resolution spectrographs. An important factor in the scarcity of high precision IR spectrographs is the high cost of these instruments. We present a new optical design, which leads to a cost-effective solution. Our instrument is a high-resolution (R = 60,000) infrared spectrograph with a R6 Echelle grating and an image slicer. We compare the best possible performance of quasi-Littrow and White Pupil setups, and prefer the latter because it achieves higher image quality. The instrument is proposed for the University of Tokyo Atacama Observatory (TAO) 6.5 m telescope in Chile. The Tao Aiuc high Resolution (d) Y band Spectrograph (TARdYS) covers 0.843-1.117 mu m. To reduce the cost, we squeeze 42 spectral orders onto a 1K detector with a semi-cryogenic solution. We obtain excellent resolution even when taking realistic manufacturing and alignment tolerances as well as thermal variations into account. In this paper, we present early results from the prototype of this spectrograph at ambient temperature.