The Nature of Optically Dull Active Galactic Nuclei in COSMOS (2009)
Trump, Jonathan R., Impey, Chris D., Taniguchi, Yoshi, Brusa, Marcella, Civano, Francesca, Elvis, Martin, ...
We present infrared, optical, and X-ray data of 48 X-ray bright, optically dull AGNs in the COSMOS field. These objects exhibit the X-ray luminosity of an active galactic nucleus (AGN) but lack broad...
Observational limits on type 1 active galactic nucleus rate in COSMOS (2009)
Trump, Jonathan R., Impey, Chris D., Kelly, Brandon C., Elvis, Martin, Merloni, A., Bongiorno, Angela, ...
We present black hole masses and accretion rates for 182 Type 1 active galactic nuclei (AGNs) in COSMOS. We estimate masses using the scaling relations for the broad H β, Mg ii, and C iv emission...
Chemical Evolution of High-Redshift Radio Galaxies (2009)
Matsuoka, Kenta, Nagao, Tohru, Maiolino, Roberto, Marconi, Alessandro, Taniguchi, Yoshiaki
We present new deep optical spectra of 9 high-z radio galaxies (HzRGs) at z > 2.7 obtained with FORS2 on VLT. These rest-frame ultraviolet spectra are used to infer the metallicity of the narrow-line...
Observational Limits on Type 1 AGN Accretion Rate in COSMOS (2009)
Trump, Jonathan R., Impey, Chris D., Kelly, Brandon C., Elvis, Martin, Merloni, Andrea, Bongiorno, Angela, ...
We present black hole masses and accretion rates for 182 Type 1 AGN in COSMOS. We estimate masses using the scaling relations for the broad Hb, MgII, and CIV emission lines in the redshift ranges 0.16
A Search for Molecular Gas toward a BzK-selected Star-forming Galaxy at z = 2.044 (2009)
Hatsukade, Bunyo, Iono, Daisuke, Motohara, Kentaro, Nakanishi, Kouichiro, Hayashi, Masao, Shimasaku, Kazuhiro, ...
We present a search for CO(3-2) emission in SDF-26821, a BzK-selected star-forming galaxy (sBzK) at z = 2.044, using the 45-m telescope of the Nobeyama Radio Observatory and the Nobeyama Millimeter...
Observational limits on type 1 active galactic nucleus accretion rate in COSMOS (2009)
Trump, Jonathan R., Impey, Chris D., Kelly, Brandon C., Elvis, Martin, Merloni, Andrea, Bongiorno, Angela, ...
Kawakatu, Nozomu, Nagao, Tohru, Woo, Jong-Hak
We investigate the optical emission-line flux ratios of narrow-line regions, in order to determine whether the formation of AGN jets requires specific accretion conditions. We find that bright...
Nakajima, Aki, Shioya, Yasuhiro, Nagao, Tohru, Saito, Tomoki, Murayama, Takashi, Sasaki, Shunji S., ...
We present our analysis on the clustering properties of star-forming galaxies selected by narrow-band excesses in the Subaru Deep Field. Specifically we focus on Halpha emitting galaxies at z = 0.24...
Marconi, Alessandro, Axon, David, Maiolino, Roberto, Nagao, Tohru, Guia, Pastorini, Pietrini, Paola, ...
Also archived in: arXiv:0802.2021 v1 14 Feb 2008
Ota, Kazuaki, Kashikawa, Nobunari, Malkan, Matthew A., Iye, Masanori, Nakajima, Tadashi, Nagao, Tohru, ...
We investigate the sky distribution of z ~ 6 Lyman break galaxies selected as i'-dropouts having i' - z' > 1.45 down to z' < 26.5 in the Subaru Deep Field (SDF). We discover 37 i'-dropouts clustered...
The Subaru/XMM-Newton Deep Survey (SXDS) - V. Optically Faint Variable Object Survey (2008)
Morokuma, Tomoki, Doi, Mamoru, Yasuda, Naoki, Masayuki, Akiyama, Sekiguchi, Kazuhiro, Furusawa, Hisanori, ...
Also archived in: arXiv:0712.3108 v1 Dev 19 2007
Nagao, Tohru, Sasaki, Shunji, Maiolino, Roberto, Grady, Celestine, Kashikawa, Nobunari, Ly, Chun, ...
We present a new photometric search for high-z galaxies hosting Population III (PopIII) stars based on deep intermediate-band imaging observations obtained in the Subaru Deep Field (SDF), by using...
Marconi, Alessandro, Axon, David, Maiolino, Roberto, Nagao, Tohru, Pastorini, Guia, Pietrini, Paola, ...
We consider the effect of radiation pressure from ionizing photons on black hole (BH) mass estimates based on the application of the virial theorem to broad emission lines in AGN spectra. BH masses...
Morokuma, Tomoki, Doi, Mamoru, Yasuda, Naoki, Akiyama, Masayuki, Sekiguchi, Kazuhiro, Furusawa, Hisanori, ...
We present the properties of active galactic nuclei (AGN) selected by optical variability in the Subaru/XMM-Newton Deep Field (SXDF). Based on the locations of variable components and light curves,...
The Subaru/XMM-Newton Deep Survey (SXDS) - V. Optically Faint Variable Object Survey (2007)
Morokuma, Tomoki, Doi, Mamoru, Yasuda, Naoki, Akiyama, Masayuki, Sekiguchi, Kazuhiro, Furusawa, Hisanori, ...
We present our survey for optically faint variable objects using multi-epoch (8-10 epochs over 2-4 years) $i'$-band imaging data obtained with Subaru Suprime-Cam over 0.918 deg$^2$ in the...
Type I Ultraluminous Infrared Galaxies: Transition Stage from ULIRGs to QSOs (2007)
Kawakatu, Nozomu, Anabuki, Naohisa, Nagao, Tohru, Umemura, Masayuki, Nakagawa, Takao
We examine whether the ultraluminous infrared galaxies that contain a type I Seyfert nucleus (a type I ULIRG) are in the transition stage from ULIRGs to quasi-stellar objects (QSOs). To inspect this...
Kawakatu, Nozomu, Imanishi, Masatoshi, Nagao, Tohru
We discovered a significant anti-correlation between the mass of a supermassive black hole (SMBH), $M_{\rm BH}$, and the luminosity ratio of infrared to active galactic nuclei (AGN) Eddington...
Nagao, Tohru, Murayama, Takashi, Maiolino, Roberto, Marconi, Alessandro, Kashikawa, Nobunari, Ajiki, Masaru, ...
We report new follow-up spectroscopy of i-dropout galaxies with an NB921-band depression found in the Subaru Deep Field. The NB921-depressed i-dropout selection method is expected to select galaxies...
The HI content of star-forming galaxies at z = 0.24 (2007)
Lah, Philip, Chengalur, Jayaram N., Briggs, Frank H., Colless, Matthew, De Propris, Roberto, Pracy, Michael B., ...
We use observations from the Giant Metrewave Radio Telescope (GMRT) to measure the atomic hydrogen gas content of star-forming galaxies at z = 0.24 (i.e. a look-backtime of ~3 Gyr). The sample of...
Metallicity Evolution of Active Galactic Nuclei (2006)
Nagao, Tohru, Maiolino, Roberto, Marconi, Alessandro
In this contribution we report our recent investigation of the gas metallicity in active galactic nuclei and its dependence on luminosity and redshift. We compile large spectroscopic datasets of...
Ly, Chun, Malkan, Matt A., Kashikawa, Nobunari, Shimasaku, Kazuhiro, Doi, Mamoru, Nagao, Tohru, ...
Abridged: Subaru Deep Field line-emitting galaxies in four narrow-band filters at low and intermediate redshifts are presented. Broad-band colors, follow-up optical spectroscopy, and multiple NB...
Gas metallicity diagnostics in star-forming galaxies (2006)
Nagao, Tohru, Maiolino, Roberto, Marconi, Alessandro
Generally the gas metallicity in distant galaxies can only be inferred by using a few prominent emission lines. Various theoretical models have been used to predict the relationship between emission...
Ajiki, Masaru, Taniguchi, Yoshiaki, Murayama, Takashi, Shioya, Yasuhiro, Nagao, Tohru, Sasaki, Shunji S., ...
Recently, Zheng et al. (2005) found evidence for an overdensity of galaxies around a radio-loud quasar, SDSS J0836+0054, at z=5.8 (a five arcmin$^2$ region). We have examined our deep optical imaging...
Ajiki, Masaru, Shioya, Yasuhiro, Taniguchi, Yoshiaki, Murayama, Takashi, Nagao, Tohru, Sasaki, Shunji S., ...
We discuss observational properties of strong emission-line galaxies at low redshift found by our deep imaging survey for high-redshift Ly alpha emitters. In our surveys, we used the narrowband...
An Intermediate-band imaging survey for high-redshift Lyman Alpha Emitters: The Mahoroba-11 (2005)
Yamada, Sanae F., Sasaki, Shunji S., Sumiya, Ryoko, Umeda, Kazuyoshi, Shioya, Yasuhiro, Ajiki, Masaru, ...
We present results of our intermediate-band optical imaging survey for high-$z$ Ly$\alpha$ emitters (LAEs) using the prime focus camera, Suprime-Cam, on the 8.2m Subaru Telescope. In our survey, we...
Narrow-Band Survey of the GOODS Fields: Search for Lyman-Alpha Emitters at z = 5.7 (2005)
Ajiki, Masaru, Mobasher, Bahram, Taniguchi, Yoshiaki, Shioya, Yasuhiro, Nagao, Tohru, Murayama, Takashi, ...
We present results from optical narrow-band lambda_c = 8150A ~ and Delta lambda = 120A) observations of the Great Observatories Origins Deep Survey (GOODS) fields, using Suprime-Cam on the Subaru...
The Evolution of the Broad-Line Region among SDSS Quasars (2005)
Nagao, Tohru, Marconi, Alessandro, Maiolino, Roberto
Based on 5344 quasar spectra taken from the SDSS Data Release 2, the dependences of various emission-line flux ratios on redshift and quasar luminosity are investigated in the ranges 2.0 < z < 4.5...
Type I ULIRGs: Transition Stage from ULIRGs to QSOs (2005)
Kawakatu, Nozomu, Anabuki, Naohisa, Nagao, Tohru, Umemura, Masayuki, Nakagawa, Takao
We examine whether the ultraluminous infrared galaxies that contain a type I Seyfert nucleus (a type I ULIRG) are in the transition stage from ULIRGs to quasi-stellar objects (QSOs). To inspect this...
Gas Metallicity in the Narrow-Line Regions of High-Redshift Active Galactic Nuclei (2005)
Nagao, Tohru, Maiolino, Roberto, Marconi, Alessandro
We analyze optical (UV rest-frame) spectra of X-ray selected narrow-line QSOs at redshift 1.5 < z < 3.7 found in the Chandra Deep Field South and of narrow-line radio galaxies at redshift 1.2 < z <...
Nagao, Tohru, Motohara, Kentaro, Maiolino, Roberto, Marconi, Alessandro, Taniguchi, Yoshiaki, Aoki, Kentaro, ...
We present a very deep near-infrared spectroscopic observation of a strong Ly_alpha emitter at z=6.33, SDF J132440.6+273607, which we used to search for HeII 1640. This emission line is expected if...
A survey of NB921 dropouts in the Subaru Deep Field (2005)
Shioya, Yasuhiro, Taniguchi, Yoshiaki, Ajiki, Masaru, Nagao, Tohru, Murayama, Takashi, Sasaki, Shunji S., ...
In order to search for high-redshift galaxies beyond $z = 6.6$ in the Subaru Deep Field, we have investigated NB921-dropout galaxies where NB921 is the narrowband filter centered at 919.6 nm with...
New High-Redshift Galaxies at $z$ = 5.8 - 6.5 in the Subaru Deep Field (2005)
Shioya, Yasuhiro, Taniguchi, Yoshiaki, Ajiki, Masaru, Nagao, Tohru, Murayama, Takashi, Sasaki, Shunji, ...
In order to search for high-redshift galaxies around $z \sim 6$ in the Subaru Deep Field, we have investigated NB816-dropout galaxies where NB816 is the narrowband filter centered at 815nm with FWHM...
The Intermediate-band Dropout Method: A New Method to Search for High-Redshift Galaxies (2005)
Shioya, Yasuhiro, Taniguchi, Yoshiaki, Ajiki, Masaru, Nagao, Tohru, Murayama, Takashi, Sasaki, Shunji, ...
We propose a new method to search for high-redshift galaxies that is based on an intermediate-band dropout technique rather than the usual broad-band dropout one. In this method, we use an...
Nagao, Tohru, Kawabata, Koji S., Murayama, Takashi, Ohyama, Youichi, Taniguchi, Yoshiaki, Shioya, Yasuhiro, ...
We report on the result of our high quality spectropolarimetric observation for the narrow-line region in a nearby Seyfert 2 galaxy, Mrk 573, by the Subaru Telescope. The polarized flux spectrum of...
A Subaru Search for Lyman-Alpha Emitters at z=5.8 with an Intermediate-Band Filter (2004)
Ajiki, Masaru, Taniguchi, Yoshiaki, Fujita, Shinobu S., Shioya, Yasuhiro, Nagao, Tohru, Murayama, Takashi, ...
We present the results of a survey for Ly-alpha emitters at z ~ 5.8 using a new intermediate-band filter centered at lambda_c = 8275 AA with Delta-lambda_FWHM = 340 AA (i.e., the spectroscopic...
Detection of Polarized Broad Emission in the Seyfert 2 Galaxy Mrk 573 (2004)
Nagao, Tohru, Kawabata, Koji S., Murayama, Takashi, Ohyama, Youichi, Taniguchi, Yoshiaki, Sumiya, Ryoko, ...
We report the discovery of the scattered emission from a hidden broad-line region (BLR) in a Seyfert 2 galaxy, Mrk 573, based on our recent spectropolarimetric observation performed at the Subaru...
The Halpha Luminosity Function of the Galaxy Cluster Abell 521 at z = 0.25 (2003)
Umeda, Kazuyoshi, Yagi, Masafumi, Yamada, Sanae F., Taniguchi, Yoshiaki, Shioya, Yasuhiro, Murayama, Takashi, ...
We present an optical multicolor-imaging study of the galaxy cluster Abell 521 at $z = 0.25$, using Suprime-Cam on the Subaru Telescope, covering an area of $32 \times 20$ arcmin$^2$ ($9.4 \times 5.8...
A Subaru Search for Lyman$\alpha$ Emitters at Redshift 5.7 (2003)
Ajiki, Masaru, Taniguchi, Yoshiaki, Fujita, Shinobu S., Shioya, Yasuhiro, Nagao, Tohru, Murayama, Takashi, ...
We present the results of a survey for Ly$\alpha$ emitters at $z\approx 5.7$ based on optical narrow-band ($\lambda_{\rm c} = 8150$ \AA ~ and $\Delta\lambda = 120$ \AA), and broad-band ($B$, $R_{\rm...
Are Two z~6 Quasars Gravitationally Lensed ? (2003)
Yamada, Sanae F., Shioya, Yasuhiro, Taniguchi, Yoshiaki, Murayama, Takashi, Ajiki, Masaru, Nagao, Tohru, ...
Several high-z (z > 5.7) quasars have been found in the course of Sloan Digital Sky Survey. The presence of such very high-z quasars is expected to give constraints on early structure formation. On...
Lyman$\alpha$ Emitters beyond Redshift 5:The Dawn of Galaxy Formation (2003)
Taniguchi, Yoshiaki, Shioya, Yasuhiro, Fujita, Shinobu S., Nagao, Tohru, Murayamaoya, Takashi, Ajiki, Masaru
The 8m class telescopes in the ground-based optical astronomy together with help from the ultra-sharp eye of the Hubble Space Telescope have enabled us to observe forming galaxies beyond redshift...
Subaru High-Dispersion Spectroscopy of Narrow-Line Region in the Seyfert Galaxy NGC 4151 (2003)
Nagao, Tohru, Murayama, Takashi, Shioya, Yasuhiro, Taniguchi, Yoshiaki
We report on a study of forbidden emission-line spectrum of nearby Seyfert 1.5 galaxy NGC 4151 based on the high-resolution (R ~ 45,000) optical spectrum obtained by using the High Dispersion...
The discovery of a very narrow line star-forming object at a redshift of 5.66 (2003)
Taniguchi, Yoshiaki, Ajiki, Masaru, Murayama, Takashi, Nagao, Tohru, Veilleux, Sylvain, Sanders, David B., ...
Nagao, Tohru, Murayama, Takashi, Shioya, Yasuhiro, Taniguchi, Yoshiaki
In order to examine whether or not high-ionization nuclear emission-line regions (HINERs) in narrow-line regions of active galactic nuclei are dusty, we focus on two high-ionization forbidden...
SDSSp J104433.04$-$012502.2 at $z=5.74$ is Gravitationally Magnified by an Intervening Galaxy (2002)
Shioya, Yasuhiro, Taniguchi, Yoshiaki, Murayama, Takashi, Ajki, Masaru, Nagao, Tohru, Fujita, Shinobu S., ...
During the course of our optical deep survey program on L$\alpha$ emitters at $z \approx 5.7$ in the sky area surrounding the quasar SDSSp J104433.04$-$012502.2 at $z=5.74$, we found that a faint...
A Search for Lyman alpha Emitters at Redshift 3.7 (2002)
Fujita, Shinobu S., Ajiki, Masaru, Shioya, Yasuhiro, Nagao, Tohru, Murayama, Takashi, Taniguchi, Yoshiaki, ...
We present the results of a survey for emission-line objects based on optical intermediate-band ($\lambda_{\rm c}$ = 5736 \AA ~ and $\Delta\lambda$ = 280 \AA) and broad-band ($B$, $V$, $R$, and...
Effects of a burst of formation of first-generation stars on the evolution of galaxies (2002)
Shioya, Yasuhiro, Taniguchi, Yoshiaki, Murayama, Takashi, Nishiura, Shingo, Nagao, Tohru, Kakazu, Yuko
First-generation (Population III) stars in the universe play an important role inearly enrichment of heavy elements in galaxies and intergalactic medium and thus affect the history of galaxies. The...
Nagao, Tohru, Murayama, Takashi, Shioya, Yasuhiro, Taniguchi, Yoshiaki
We investigate gas metallicity of narrow-line regions in narrow-line Seyfert 1 galaxies (NLS1s) and broad-line ones (BLS1s) in order to examine whether or not there is a difference in the gas...
Nagao, Tohru, Murayama, Takashi, Shioya, Yasuhiro, Taniguchi, Yoshiaki
In order to examine the prediction that the broad-line radio galaxies (BLRGs) with double-peaked Balmer lines harbor an accretion disk characterized by an advection-dominated accretion flow (ADAF) in...
A Shock-Induced Pair of Superbubbles in the High-Redshift Powerful Radio Galaxy MRC 0406-244 (2001)
Taniguchi, Yoshiaki, Ohyama, Youichi, Murayama, Takashi, Yoshida, Michitoshi, Kashikawa, Nobunari, Iye, Masanori, ...
We present new optical spectroscopy of the high-redshift powerful radio galaxy MRC 0406$-$244 at redshift of 2.429. We find that the two extensions toward NW and SE probed in the rest-frame...
Nagao, Tohru, Murayama, Takashi, Taniguchi, Yoshiaki
In order to examine how narrow emission-line flux ratios depend on the Seyfert type, we compiled various narrow emission-line flux ratios of 355 Seyfert galaxies from the literature. We present in...
The [O III]4363 Emitting Region Obscured by Dusty Tori (2001)
Nagao, Tohru, Murayama, Takashi, Taniguchi, Yoshiaki
The emission-line flux ratio of [O III]4363/[O III]5007 is a useful diagnostic for the ionization mechanism and physical properties of narrow-line regions in active galactic nuclei. However, it is...
Where is the [O III]4363 emitting region in active galactic nuclei? (2000)
Nagao, Tohru, Murayama, Takashi, Taniguchi, Yoshiaki
The emission-line flux ratio of [O III]4363/[O III]5007 (R_OIII)is a useful diagnostic for the ionization mechanism and physical properties of emission-line regions in active galactic nuclei (AGNs)....
The High-Ionization Nuclear Emission-Line Region of Seyfert Galaxies (2000)
Nagao, Tohru, Taniguchi, Yoshiaki, Murayama, Takashi
Recently Murayama & Taniguchi proposed that a significant part of the high-ionization nuclear emission-line region (HINER) in Seyfert nuclei arises from the inner wall of dusty tori because type 1...
Discovery of a Low Surface Brightness Object near Seyfert's Sextet (2000)
Murayama, Takashi, Nishiura, Shingo, Nagao, Tohru, Sato, Yasunori, Taniguchi, Yoshiaki, Sanders, D. B.
We report the discovery of a low surface brightness (LSB) object serendipitously found during deep CCD imaging of a compact group of galaxies, Seyfert's Sextet, in VR and I bands. The LSB object is...
Extended High-Ionization Nuclear Emission-Line Region in the Seyfert Galaxy NGC 4051 (1999)
Nagao, Tohru, Murayama, Takashi, Taniguchi, Yoshiaki, Yoshida, Michitoshi
We present an optical spectroscopic analysis of the well-known Seyfert galaxy NGC 4051. The high-ionization nuclear emission-line region (HINER) traced by [Fe X]6374 is found to be spatially extended...
Taniguchi, Yoshiaki, Murayama, Takashi, Nagao, Tohru
Recently growing evidence has been accumulated that the NLS1s are viewed from nearly pole-on viewing angles. However, there has been no theoretical model which explains the following important...