Search Publications
AKARI Near-infrared Spectroscopic Survey for CO2 in 18 Comets
Nakagawa, Takao; Onaka, Takashi; Usui, Fumihiko +11 more
We conducted a spectroscopic survey of cometary volatiles with the Infrared Camera on board the Japanese infrared satellite AKARI in the wavelength range from 2.5 to 5 µm. In our survey, 18 comets, including both the Oort cloud comets and the Jupiter-family comets, were observed in the period from 2008 June to 2010 January, most of which wer…
Polarimetric Imaging of Large Cavity Structures in the Pre-transitional Protoplanetary Disk around PDS 70: Observations of the Disk
Kuzuhara, M.; Tamura, M.; Ishii, M. +52 more
We present high-resolution H-band polarized intensity (FWHM = 0farcs1: 14 AU) and L'-band imaging data (FWHM = 0farcs11: 15 AU) of the circumstellar disk around the weak-lined T Tauri star PDS 70 in Centaurus at a radial distance of 28 AU (0farcs2) up to 210 AU (1farcs5). In both images, a giant inner gap is clearly resolved for the first time, an…
Mid- and Far-infrared Properties of a Complete Sample of Local Active Galactic Nuclei
Nakagawa, Takao; Oyabu, Shinki; Gandhi, Poshak +4 more
We investigate the mid- (MIR) to far-infrared (FIR) properties of a nearly complete sample of local active galactic nuclei (AGNs) detected in the Swift/Burst Alert Telescope (BAT) all-sky hard X-ray (14-195 keV) survey, based on the cross correlation with the AKARI infrared survey catalogs complemented by those with Infrared Astronomical Satellite…
Reexamination of the Infrared Excess-Ultraviolet Slope Relation of Local Galaxies
Inoue, Akio K.; Murata, Katsuhiro L.; Takeuchi, Tsutomu T. +2 more
The relation between the ratio of infrared (IR) and ultraviolet (UV) flux densities (the infrared excess: IRX) and the slope of the UV spectrum (β) of galaxies plays a fundamental role in the evaluation of the dust attenuation of star-forming galaxies, especially at high redshifts. Many authors, however, have pointed out that there is a significan…
Reconstructing the Near-infrared Background Fluctuations from Known Galaxy Populations Using Multiband Measurements of Luminosity Functions
Ricotti, Massimo; Kashlinsky, Alexander; Helgason, Kari
We model fluctuations in the cosmic infrared background (CIB) arising from known galaxy populations using 233 measured UV, optical, and near-IR luminosity functions (LFs) from a variety of surveys spanning a wide range of redshifts. We compare best-fit Schechter parameters across the literature and find clear indication of evolution with redshift.…
The Near-infrared Background Intensity and Anisotropies during the Epoch of Reionization
Gong, Yan; Cooray, Asantha; Smidt, Joseph +1 more
A fraction of the extragalactic near-infrared (near-IR) background light involves redshifted photons from the ultraviolet (UV) emission from galaxies present during reionization at redshifts above 6. The absolute intensity and the anisotropies of the near-IR background provide an observational probe of the first-light galaxies and their spatial di…
Search for Gamma-ray Emission from X-Ray-selected Seyfert Galaxies with Fermi-LAT
Ozaki, M.; Troja, E.; Caraveo, P. A. +133 more
We report on a systematic investigation of the γ-ray properties of 120 hard X-ray-selected Seyfert galaxies classified as "radio-quiet" objects, utilizing the three-year accumulation of Fermi Large Area Telescope (LAT) data. Our sample of Seyfert galaxies is selected using the Swift Burst Alert Telescope 58 month catalog, restricting the analysis …
Double Bow Shocks around Young, Runaway Red Supergiants: Application to Betelgeuse
Langer, Norbert; Neilson, Hilding R.; Mackey, Jonathan +2 more
A significant fraction of massive stars are moving supersonically through the interstellar medium (ISM), either due to disruption of a binary system or ejection from their parent star cluster. The interaction of their wind with the ISM produces a bow shock. In late evolutionary stages these stars may undergo rapid transitions from red to blue and …
Observations of the near- to Mid-infrared Unidentified Emission Bands in the Interstellar Medium of the Large Magellanic Cloud
Onaka, Takashi; Sakon, Itsuki; Kaneda, Hidehiro +3 more
We present the results of near- to mid-infrared slit spectroscopic observations (2.55-13.4 µm) of the diffuse emission toward nine positions in the Large Magellanic Cloud with the infrared camera on board AKARI. The target positions are selected to cover a wide range of the intensity of the incident radiation field. The unidentified infrared…
AKARI Observations of Brown Dwarfs. III. CO, CO2, and CH4 Fundamental Bands and Physical Parameters
Yamamura, I.; Sorahana, S.
We investigate variations in the strengths of three molecular bands, CH4 at 3.3 µm, CO at 4.6 µm, and CO2 at 4.2 µm, in 16 brown dwarf spectra obtained by AKARI. Spectral features are examined along the sequence of source classes from L1 to T8. We find that the CH4 3.3 µm band is present in …