Subaru FOCAS Spectroscopic Observations of High-Redshift Supernovae (2009)
Morokuma, Tomoki, Tokita, Kouichi, Lidman, Christopher, Doi, Mamoru, Yasuda, Naoki, Aldering, Greg, ...
We present spectra of high-redshift supernovae (SNe) that were taken with the Subaru low resolution optical spectrograph, FOCAS. These SNe were found in SN surveys with Suprime-Cam on Subaru, the...
Size Evolution of Early-Type Galaxies and Massive Compact Objects as the Dark Matter (2009)
The dramatic size evolution of early-type galaxies from z ~ 2 to 0 poses a new challenge in the theory of galaxy formation, which may not be explained by the standard picture. It is shown here that...
Probing the Gamma-Ray Burst Progenitor by Lyman-Alpha Emission of Host Galaxies (2009)
Niino, Yuu, Totani, Tomonori, Kobayashi, Masakazu A. R.
Theoretical and observational studies suggest that long gamma-ray bursts (GRBs) preferentially occur in low metallicity environment. We discuss the possibility and theoretical aspects of using Lyman...
Kobayashi, Masakazu A. R., Totani, Tomonori, Nagashima, Masahiro
We present theoretical predictions of UV continuum luminosity function (UV LF) and Lya equivalent width (EW) distribution of Lyman alpha emitters (LAEs) in the framework of the hierarchical...
Sumiyoshi, Masanao, Totani, Tomonori, Oshige, Shunsuke, Glazebrook, Karl, Akiyama, Masayuki, Morokuma, Tomoki, ...
Efficient selection of emission line galaxies at z > 1 by photometric information in wide field surveys is one of the keys for future spectroscopic surveys to constrain dark energy using the baryon...
Sumiyoshi, Masanao, Totani, Tomonori, Oshige, Shunsuke, Glazebrook, Karl, Akiyama, Masayuki, Morokuma, Tomoki, ...
Efficient selection of emission line galaxies at z > 1 by photometric information in wide field surveys is one of the keys for future spectroscopic surveys to constrain dark energy using the baryon...
Sumiyoshi, Masanao, Totani, Tomonori, Oshige, Shunsuke, Glazebrook, Karl, Akiyama, Masayuki, Morokuma, Tomoki, ...
Efficient selection of emission line galaxies at z > 1 by photometric information in wide field surveys is one of the keys for future spectroscopic surveys to constrain dark energy using the baryon...
The Blazar Sequence and the Cosmic Gamma-Ray Background Radiation in the Fermi Era (2008)
Inoue, Yoshiyuki, Totani, Tomonori
We present a new model of the blazar gamma-ray luminosity function (GLF) and the spectrum of the extragalactic gamma-ray background (EGRB), which is consistent with the observed distributions of...
Aoki, Kentaro, Totani, Tomonori, Hattori, Takashi, Ohta, Kouji, Kawabata, Koji S., Kobayashi, Naoto, ...
We examine variability of absorption line strength of intervening systems along the line of sight to GRB 060206 at $z = 4.05$, by the low-resolution optical spectra obtained by the Subaru telescope...
Totani, Tomonori, Morokuma, Tomoki, Oda, Takeshi, Doi, Mamoru, Yasuda, Naoki
The delay time distribution (DTD) of type Ia supernovae (SNe Ia) from star formation is an important clue to reveal the still unknown progenitor system of SNe Ia. Here we report on a measurement of...
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
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...
Inoue, Yoshiyuki, Totani, Tomonori, Ueda, Yoshihiro
The origin of the extragalactic gamma-ray background radiation at 1-10 MeV is still unknown. Although the cosmic X-ray background (CXB) up to a few hundreds keV can be accounted for by the sum of...
The Reionization and Galaxy Evolution Probed by z=7 Lyman Alpha Emitters (2007)
Ota, Kazuaki, Iye, Masanori, Kashikawa, Nobunari, Shimasaku, Kazuhiro, Kobayashi, Masakazu A. R., Totani, Tomonori, ...
We made a narrowband NB973 (bandwidth of 200A at 9755A) imaging of the Subaru Deep Field (SDF) and found two z=7 Lyman alpha emitter (LAE) candidates down to NB973=24.9. Carrying out deep follow-up...
Supernovae in the Subaru Deep Field: An Initial Sample, and Type Ia Rate, out to Redshift 1.6 (2007)
Poznanski, Dovi, Maoz, Dan, Yasuda, Naoki, Foley, Ryan J., Doi, Mamoru, Filippenko, Alexei V., ...
Large samples of high-redshift supernovae (SNe) are potentially powerful probes of cosmic star formation, metal enrichment, and SN physics. We present initial results from a new deep SN survey, based...
Intracluster Short Gamma-Ray Bursts by Compact Binary Mergers (2007)
One of the possible origins of short gamma-ray bursts (SGRBs) is merging of compact binaries, and the effect of large kick velocity is a signature that can be used as an observational test for this...
Lyman Alpha Emitters in the Hierarchically Clustering Galaxy Formation (2007)
Kobayashi, Masakazu A. R., Totani, Tomonori, Nagashima, Masahiro
We present a new theoretical model for the luminosity functions (LFs) of Lyman alpha (Lya) emitting galaxies in the framework of hierarchical galaxy formation. We extend a semi-analytic model of...
Angular power spectrum of gamma-ray sources for GLAST: blazars and clusters of galaxies (2007)
Ando, Shin'ichiro, Komatsu, Eiichiro, Narumoto, Takuro, Totani, Tomonori
Blazars, a beamed population of active galactic nuclei, radiate high-energy γ-rays, and thus are a good target for the Gamma Ray Large Area Space Telescope (GLAST). As the blazars trace the...
Ando, Shin'ichiro, Komatsu, Eiichiro, Narumoto, Takuro, Totani, Tomonori
The origin of the cosmic gamma-ray background (CGB) is a longstanding mystery in high-energy astrophysics. Possible candidates include ordinary astrophysical objects such as unresolved blazars, as...
Ando, Shin'ichiro, Komatsu, Eiichiro, Narumoto, Takuro, Totani, Tomonori
The origin of the cosmic gamma-ray background (CGB) is a longstanding mystery in high-energy astrophysics. Possible candidates include ordinary astrophysical objects such as unresolved blazars, as...
Angular power spectrum of gamma-ray sources for GLAST: blazars and clusters of galaxies (2006)
Ando, Shin'ichiro, Komatsu, Eiichiro, Narumoto, Takuro, Totani, Tomonori
Blazars, a beamed population of active galactic nuclei, radiate high-energy gamma-rays, and thus are a good target for the Gamma Ray Large Area Space Telescope (GLAST). As the blazars trace the...
There are several lines of evidence that the super-massive black hole at the Galactic center had higher activities in the past than directly observed at present. Here I show that these lines of...
Narumoto, Takuro, Totani, Tomonori
We present a comprehensive study for the gamma-ray luminosity function (GLF) of blazars and their contribution to the extragalactic diffuse gamma-ray background (EGRB). Radio and gamma-ray luminosity...
Totani, Tomonori, Kawai, Nobuyuki, Kosugi, George, Aoki, Kentaro, Yamada, Toru, Iye, Masanori, ...
The gamma-ray burst (GRB) 050904 at z = 6.3 provides the first opportunity of probing the intergalactic medium (IGM) by GRBs at the epoch of the reionization. Here we present a spectral modeling...
Subaru Super Deep Field with Adaptive Optics I. Observations and First Implications (2005)
Minowa, Yosuke, Kobayashi, Naoto, Yoshii, Yuzuru, Totani, Tomonori, Maihara, Toshinori, Iwamuro, Fumihide, ...
We present a deep $K^{\prime}$-band (2.12$\mu$m) imaging of 1\arcmin\ $\times$ 1\arcmin Subaru Super Deep Field (SSDF) taken with the Subaru adaptive optics (AO) system. Total integration time of...
Oda, Takeshi, Totani, Tomonori
We investigate the prospects of future supernova searches to get meaningful constraints about the cosmic star formation history (CSFH) and the delay time of type Ia supernovae from star formation...
Gamma-Ray Background from Neutralino Annihilation in the First Cosmological Objects (2005)
Oda, Takeshi, Totani, Tomonori, Nagashima, Masahiro
The paradigm of the neutralino dark matter predicts that the first gravitationally bound objects are earth-mass sized microhaloes, which would emit annihilation gamma-rays. Here we show that, though...
A Discovery of Rapid Optical Flares from Low-Luminosity Active Nuclei in Massive Galaxies (2005)
Totani, Tomonori, Sumi, Takahiro, Kosugi, George, Yasuda, Naoki, Doi, Mamoru, Oda, Takeshi
We report a serendipitous discovery of six very low-luminosity active galactic nuclei (AGNs) only by optical variability in one-month baseline. The detected flux variability is ~ 1-5% of the total...
Accumulating evidence indicates that some of ultra-luminous X-ray sources (ULXs) are intermediate mass black holes (IMBHs), but the formation process of IMBHs is unknown. One possibility is that they...
Submillimetre Constraints on Hyper-Extremely Red Objects in the Subaru Deep Field (2004)
Coppin, Kristen, Halpern, Mark, Scott, Douglas, Marsden, Gaelen, Iwamuro, Fumihide, Maihara, Toshinori, ...
We have mapped the submillimetre wavelength continuum emission from the Subaru Deep Field (SDF) at 450 and 850 microns with the Submillimetre Common-User Bolometer Array (SCUBA) detector on the James...
Solving the Cooling Flow Problem of Galaxy Clusters by Dark Matter Neutralino Annihilation (2004)
Recent X-ray observations revealed that strong cooling flow of intracluster gas is not present in galaxy clusters, even though predicted theoretically if there is no additional heating source. I show...
(Abridged) SN 2002ap is an interesting event with broad spectral features like the famous SN 1998bw / GRB 980425. Here we examine the recently proposed jet hypothesis from SN 2002ap by a...
The galaxy cluster Abell 2152 is recently found to be forming a cluster-cluster system with another, more distant cluster whose core is almost perfectly aligned to that of A2152. We discuss the...
Deep Near-Infrared Universe Seen in the Subaru Deep Field (2002)
The Subaru Deep Field provides the currently deepest K-selected sample of high-z galaxies (K' = 23.5 at 5 sigma). The SDF counts, colors, and size distributions in the near-infrared bands are...
Kashikawa, Nobunari, Takata, Tadafumi, Ohyama, Youichi, Yoshida, Michitoshi, Maihara, Toshinori, Iwamuro, Fumihide, ...
We have constructed a very deep K'-selected multicolor BVRIz'JK' sample of 439 field galaxies. Photometric redshifts for sample galaxies were estimated. The overall redshift distribution N(z) for the...
Totani, Tomonori, Panaitescu, Alin
We make a quantitative prediction for the detection rate of orphan GRB afterglows as a function of flux sensitivity in X-ray, optical, and radio wavebands, based on a recent model of collimated GRB...
Totani, Tomonori, Takeuchi, Tsutomu T.
We give an explanation for the origin of various properties observed in local infrared galaxies, and make predictions for galaxy counts and cosmic background radiation (CBR), by a new model extended...
Kawasaki, Wataru, Totani, Tomonori
We report an evidence for the first time that merging clusters of galaxies are a promising candidate for the origin of high galactic-latitude, steady unidentified EGRET gamma-ray sources. Instead of...
Totani, Tomonori, Yoshii, Yuzuru, Iwamuro, Fumihide, Maihara, Toshinori, Motohara, Kentaro
We report observational analyses and theoretical interpretations of unusually red galaxies in the Subaru Deep Field (SDF). A careful analysis of the SDF data revealed a population with unusually red...
Preheating in the Universe Suppressing High Energy Gamma-rays from Structure Formation (2001)
Totani, Tomonori, Inoue, Susumu
Structure formation in the universe can produce high energy gamma-rays from shock-accelerated electrons, and this process may be the origin of the extragalactic gamma-ray background (EGRB) as well as...
Forming Clusters of Galaxies as the Origin of Unidentified GeV Gamma-Ray Sources (2000)
Totani, Tomonori, Kitayama, Tetsu
Over half of GeV gamma-ray sources observed by the EGRET experiment have not yet been identified as known astronomical objects. There is an isotropic component of such unidentified sources, whose...
Zwart, Simon Portegies, Totani, Tomonori
We present an internal shock model with external characteristics for explaining the complicated light curves of gamma-ray bursts. Shocks produce gamma-rays in the interaction between a precessing...
Dust versus Supernova Cosmology (2000)
Here we present some critical discussions about the systematic uncertainty by dust extinction in the recent cosmological results of high-redshift Type Ia supernovae. First we argue that the currently...
An Interpretation of the Evidence for TeV Emission from Gamma-Ray Burst 970417a (2000)
The Milagrito collaboration recently reported evidence for emission of very high energy gamma-rays in the TeV range from one of the BATSE GRBs, GRB 970417a. Here I discuss possible interpretations of...
Totani, Tomonori, Yoshii, Yuzuru
(Abridged) We present a detailed analysis of the number count and photometric redshift distribution of faint galaxies in the Hubble Deep Field (HDF), paying a special attention to the selection...
Evolution of Dust Extinction and Supernova Cosmology (1999)
Totani, Tomonori, Kobayashi, Chiaki
We have made a quantitative calculation for the systematic evolution of average extinction by interstellar dust in host galaxies of high-redshift Type Ia supernovae, by using a realistic model of...
The extreme energetics of the gamma-ray burst (GRB) 990123 has revealed that some of GRBs emit quite a large amount of energy, and total energy release from GRBs seems to change from burst to burst...
Galaxy Formation by Galactic Magnetic Fields (1999)
Galaxies exhibit a sequence of various morphological types, i.e., the Hubble sequence, and they are basically composed of spheroidal components (elliptical galaxies and bulges in spiral galaxies) and...
TeV Burst of Gamma-Ray Bursts and Ultra High Energy Cosmic Rays (1998)
Some recent experiments detecting very high energy (VHE) gamma-rays above 10-20 TeV independently reported VHE bursts for some of bright gamma-ray bursts (GRBs). If these signals are truly from GRBs,...
Gamma-Ray Bursts, Ultra High Energy Cosmic Rays, and Cosmic Gamma-Ray Background (1998)
We argue that gamma-ray bursts (GRBs) may be the origin of the cosmic gamma-ray background radiation observed in GeV range. It has theoretically been discussed that protons may carry a much larger...
Does the Number Density of Elliptical Galaxies Change at z (1998)
Totani, Tomonori, Yoshii, Yuzuru
We have performed a detailed V/Vmax test for a sample of the Canada-France Redshift Survey (CFRS) for the purpose of examining whether the comoving number density of field galaxies changes...
Very Strong TeV Emission as Gamma-Ray Burst Afterglows (1998)
Gamma-ray bursts (GRBs) and following afterglows are considered to be produced by dissipation of kinetic energy of a relativistic fireball and radiation process is widely believed as synchrotron...
Probing the Cosmic Star Formation History by Brightness Distribution of Gamma-Ray Bursts (1998)
Brightness distribution of Gamma-Ray Bursts (GRBs) is studied in detail under the assumption that GRB rate is related to cosmic star formation rate. The two populations of the long- and...
We present a new strategy for measuring the electron neutrino mass ($\mnue$) by future detection of a Galactic supernova in large underground detectors such as the Super-Kamiokande (SK). This method...
Gamma-Ray Bursts from Neutron Star Mergers and Evolution of Galaxies (1998)
Most of proposed models of cosmological gamma-ray bursts (GRBs) are associated to gravitational collapses of massive stars, and hence evolution of the GRB rate, which is crucially important in GRB...
Luminosity Density Evolution in the Universe and Cosmological Parameters (1997)
Star formation history in galaxies is strongly correlated to their present-day colors and the Hubble sequence can be considered as a sequence of different star formation history. Therefore we can...
Cosmological Gamma-Ray Bursts and Evolution of Galaxies (1997)
Evolution of the rate density of cosmological gamma-ray bursts (GRBs) is calculated and compared to the BATSE brightness distribution in the context of binary neutron-star mergers as the source of...
Totani, Tomonori, Sato, Katsuhiko
The neutrino spin-flavor conversion of \bar\nu_e and \nu_\mu which is induced by the interaction of the Majorana neutrino magnetic moment and magnetic fields in the collapse-driven supernova is...
Effects of Neutrino Oscillation on the Supernova Relic Neutrino Background (1996)
Totani, Tomonori, Sato, Katsuhiko
We investigate to what extent the oscillation or conversion of neutrinos enhances the expected event rate of the supernova relic neutrino background (SRN) at the Super-Kamiokande detector (SK). The...
Spectrum of the Supernova Relic Neutrino Background and Evolution of Galaxies (1995)
Totani, Tomonori, Sato, Katsuhiko, Yoshii, Yuzuru
The spectrum of the supernova relic neutrino background (SRN) from collapse-driven supernovae ever occurred in the universe is calculated by using a realistic, time-dependent supernova rate derived...
Spectrum of the relic neutrino background from past supernovae and cosmological models (1995)
Totani, Tomonori, Sato, Katsuhiko
It is greatly expected that the relic neutrino background from past supernovae is detected by Superkamiokande (SK) which is now under construction. We calculate the spectrum and the event rate at SK...