Search Publications
Comparison between Hinode/SOT and SDO/HMI, AIA data for the study of the solar flare trigger process
Kusano, Kanya; Bamba, Yumi; Iida, Yusuke +1 more
Understanding the mechanism that produces solar flares is important not only from the scientific point of view but also for improving space weather predictability. There are numerous observational and computational studies that have attempted to reveal the onset mechanism of solar flares. However, the underlying mechanism of flare onset remains el…
Probing the accretion scheme of the dipping X-ray binary 4U 1915-05 with Suzaku
Makishima, Kazuo; Zhang, Zhongli; Sasano, Makoto +2 more
The dipping low-mass X-ray binary 4U 1915-05 was observed by Suzaku on 2007 November 8 for a net exposure of 39 ks. It was detected by the XIS with a 0.8-10 keV signal rate of 9.84 ± 0.01 cts s-1 per camera, and HXD-PIN with a 12-45 keV signal rate of 0.29 ± 0.01 cts s-1. After removing the periodic dips and an X-ray burst, t…
VLBI observations of H2O maser annual parallax and proper motion in IRAS 20143+3634: Reflection on the Galactic constants
Hayashi, Masahiko; Nakagawa, Akiharu; Omodaka, Toshihiro +8 more
We report the results of very long baseline interferometry (VLBI) observations of H2O masers in the IRAS 20143+3634 star-forming region (SFR) using VERA (VLBI Exploration of Radio Astrometry). By tracking masers for a period of over two years we measured a trigonometric parallax of π = 0.367 ± 0.037 mas, corresponding to a source distan…
Suzaku discovery of Fe K-shell line from the O-rich SNR G292.0+1.8
Katsuda, Satoru; Koyama, Katsuji; Uchida, Hiroyuki +7 more
We report the Suzaku/XIS results of the Galactic oxygen-rich supernova remnant G292.0+1.8, a remnant of a core-collapse supernova. The X-ray spectrum of G292.0+1.8 consists of two types of plasma, one is in collisional ionization equilibrium (CIE) and the other is in non-equilibrium ionization (NEI). The CIE plasma has nearly solar abundances, and…
AKARI infrared camera observations of the 3.3 µm PAH feature in Swift/BAT AGNs
Nakagawa, Takao; Shirahata, Mai; Oyabu, Shinki +6 more
We explore the relationships between the 3.3 µm polycyclic aromatic hydrocarbon (PAH) feature and active galactic nucleus (AGN) properties of a sample of 54 hard X-ray selected bright AGNs, including both Seyfert 1 and Seyfert 2 type objects, using the InfraRed Camera (IRC) on board the infrared astronomical satellite AKARI. The sample is se…
Observations of umbral dots and their physical models
Watanabe, Hiroko
The Hinode satellite opens a new era in sunspot research, because of its high spatial resolution and temporal stability. Fine-scale structures in sunspots, called umbral dots (UDs), have become one of the hottest topics in terms of close observations of magnetoconvection. In this paper, a brief review of the observed properties of UDs is given bas…
Point source calibration of the AKARI/FIS all-sky survey maps for stacking analysis
Doi, Yasuo; Takita, Satoshi; Arimatsu, Ko +5 more
Investigations of the point spread functions (PSFs) and flux calibrations for stacking analysis have been performed with the far-infrared (wavelength range of 60 to 140 µm) all-sky maps taken by the Far-Infrared Surveyor (FIS) on board the AKARI satellite. The PSFs are investigated by stacking the maps at the positions of standard stars with…
Broad-band spectroscopy of Hercules X-1 with Suzaku
Enoto, Teruaki; Yamada, Shin'ya; Tamagawa, Toru +4 more
Hercules X-1 was observed with Suzaku in the main-on state from 2005 to 2010. The 0.4-100 keV wide-band spectra obtained in four observations showed a broad hump around 4-9 keV in addition to narrow Fe lines at 6.4 and 6.7 keV. The hump was seen in all the four observations regardless of the selection of the continuum models. Thus it is considered…
Morphological study of penumbral formation
Kitai, Reizaburo; Watanabe, Hiroko; Otsuji, Ken'ichi
Penumbrae are known to be areas of mainly horizontal magnetic field surrounding umbrae of relatively large and mature sunspots. In this paper, we observationally studied the formation of penumbrae in NOAA 10978, where several penumbral formations were observed in G-band images of the Solar Optical Telescope on board Hinode. Thanks to the continuou…
Constraint on the gas-to-dust ratio in massive star-forming galaxies at z ∼ 1.4
Iono, Daisuke; Hatsukade, Bunyo; Ohta, Kouji +3 more
We carried out 12CO (J = 2-1) observations toward three star-forming galaxies on the main sequence at z ∼ 1.4 with the Nobeyama 45 m radio telescope. These galaxies have been detected with Spitzer/MIPS in 24 µm, Herschel/SPIRE in 250 µm and 350 µm; their gas metallicity, derived from optical emission line ratios based …