Search Publications
A New X-Ray Spectro-Temporal Analysis Method and Its Application to the Suzaku MCG -6-30-15 Data
Ebisawa, Ken; Inoue, Hajime; Miyakawa, Takehiro
A new X-ray spectro-temporal data-analysis method, which we call "the difference variation function method", is introduced. It can analyze spectral and temporal variations of X-ray sources, and its merits are discussed in comparison with conventional data-analysis methods. The new method is being applied to Suzaku observation data of the Seyfert 1…
A Close Encounter with a Saturn Kilometric Radiation Source Region
Schippers, P.; André, N.; Gurnett, D. A. +18 more
Earth-orbiting satellites have routinely traversed the source regions of auroral kilometric radiation. This radio emission is generated via the cyclotron maser instability very close to the electron cyclotron frequency. While Cassini's orbit has crossed auroral field lines, the radial distance at auroral latitudes is typically too high for the ana…
A Detection of an X-ray Wind and an Ionized Disk in the Chandra HETGS Observation of the Seyfert 2 Galaxy IRAS 18325-5926
Lee, Julia C.; Canizares, Claude R.; Iwasawa, Kazushi +1 more
We analyze the Chandra High Energy Transmission Grating Spectrometer observation of the Seyfert 2 AGN IRAS 18325-5926. We detect a v = -360+41 -66 km s-1 blueshifted ionized absorber in the X-ray spectrum, with photoionization parameter log ξ = 2.0+0.1 -0.1 and hydrogen column density N H…
Fractal dimension and thermodynamic fluctuation properties of IDV light curves
Leung, Chun-Sing; Wei, Jian-Yan; Kovács, Zoltan +1 more
Fractals are a basic tool for phenomenologically describing natural objects having a high degree of temporal or spatial variability. From a physical point of view the fractal properties of natural systems can also be interpreted by using the standard formalism of thermodynamical fluctuations. We introduce and analyze the fractal dimension of the I…
A 2007 photometric study and UV spectral analysis of the Wolf-Rayet binary V444 Cyg
Ekmekçi, F.; Eriş, F. Z.
Photometric and spectroscopic characteristics of the WN5+O6 binary system, V444 Cyg, were studied. The Wilson-Devinney (WD) analysis, using new BV observations carried out at the Ankara University Observatory, revealed the masses, radii, and temperatures of the components of the system as MWR=10.64 M⊙, MO=24.68 M
The low-luminosity active galactic nucleus in the centre of the Galaxy
Contini, M.
The observations of far-infrared line and continuum spectra throughout the Galactic Centre and in some regions of the disc are analysed in order to determine the physical conditions (densities, shock velocities, radiation parameters etc.) and the relative abundances of some elements (C, N and O). Consistent model calculations of the line and conti…
Dark matter-rich early-type galaxies in the CASSOWARY 5 strong lensing system
Grillo, C.; Christensen, L.
We study the strong gravitational lensing system number 5 identified by the CAmbridge Sloan Survey Of Wide ARcs in the skY (CASSOWARY). In this system, a source at redshift 1.069 is lensed into four detected images by two early-type galaxies at redshift 0.388. The average projected angular distance of the multiple images from the primary lens is 1…
Importance of far-infrared mapping in a spiral galaxy: AKARI observation of M81
Sun, Ai-Lei; Hirashita, Hiroyuki
The importance of the far-infrared (FIR) mapping is demonstrated for a face-on spiral galaxy, M81, by analysing its imaging data at 65, 90 and ? taken by AKARI. The basic products are the dust temperature map, the dust optical depth map and the colour-colour diagram. The main features are as follows. (i) The dust temperature derived from the total…
Hubble Space Telescope Pixel Analysis of the Interacting Face-on Spiral Galaxy NGC 5194 (M51A)
Lee, Joon Hyeop; Kyeong, Jaemann; Kim, Sang Chul +3 more
A pixel analysis is carried out on the interacting face-on spiral galaxy NGC 5194 (M51A), using the Hubble Space Telescope (HST)/Advanced Camera for Surveys (ACS) images in the F435W, F555W, and F814W (BVI) bands. After 4 × 4 binning of the HST/ACS images to secure a sufficient signal-to-noise ratio for each pixel, we derive several quantities des…
A parsec-scale outflow from the luminous YSO IRAS 17527-2439
Varricatt, W. P.
Aims: We seek to understand the way massive stars form. The case of a luminous YSO IRAS 17527-2439 is studied in the infrared.
Methods: Imaging observations of IRAS 17527-2439 are obtained in the near-IR JHK photometric bands and in a narrow-band filter centred at the wavelength of the H2 1-0S(1) line. The continuum-subtracted…