Search Publications
Semi-analytic modelling of the extragalactic background light and consequences for extragalactic gamma-ray spectra
Somerville, Rachel S.; Primack, Joel R.; Domínguez, Alberto +1 more
Attenuation of high-energy gamma-rays by pair production with ultraviolet, optical and infrared (IR) extragalactic background light (EBL) photons provides a link between the history of galaxy formation and high-energy astrophysics. We present results from our latest semi-analytic models (SAMs), which employ the main ingredients thought to be impor…
Fundamental parameters and infrared excesses of Hipparcos stars
Zijlstra, A. A.; Boyer, M. L.; McDonald, I.
We derive the fundamental parameters (temperature and luminosity) of 107 619 Hipparcos stars and place these stars on a true Hertzsprung-Russell diagram. This is achieved by comparing BT-SETTL model atmospheres to spectral energy distributions (SEDs) created from Hipparcos, Tycho, Sloan Digital Sky Survey, DENIS, Two Micron All Sky Survey, MSX, AK…
Galaxy properties from the ultraviolet to the far-infrared: Λ cold dark matter models confront observations
Somerville, Rachel S.; Primack, Joel R.; Domínguez, Alberto +1 more
We combine a semi-analytic model of galaxy formation with simple analytic recipes describing the absorption and re-emission of starlight by dust in the interstellar medium of galaxies. We use the resulting models to predict galaxy counts and luminosity functions from the far-ultraviolet (FUV) to the submillimetre, from redshift five to the present…
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…
The Galaxy Zoo survey for giant AGN-ionized clouds: past and present black hole accretion events
Schawinski, Kevin; Sonnenfeld, Alessandro; Keel, William C. +8 more
Some active galactic nuclei (AGN) are surrounded by extended emission-line regions (EELRs), which trace both the illumination pattern of escaping radiation and its history over the light travel time from the AGN to the gas. From a new set of such EELRs, we present evidence that the AGN in many Seyfert galaxies undergo luminous episodes 0.2-2 ? yea…
Galactic cold cores. III. General cloud properties
Bernard, J. -P.; Falgarone, E.; Juvela, M. +15 more
Context. In the project galactic cold cores we are carrying out Herschel photometric observations of cold regions of the interstellar clouds as previously identified with the Planck satellite. The aim of the project is to derive the physical properties of the population of cold clumps and to study its connection to ongoing and future star formatio…
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…
Herschel images of Fomalhaut. An extrasolar Kuiper belt at the height of its dynamical activity
Ivison, R. J.; Fridlund, M.; Blommaert, J. A. D. L. +33 more
Context. Fomalhaut is a young (2 ± 1 × 108 years), nearby (7.7 pc), 2 M⊙ star that is suspected to harbor an infant planetary system, interspersed with one or more belts of dusty debris.
Aims: We present far-infrared images obtained with the Herschel Space Observatory with an angular resolution between 5.7'' and 36.7'' a…
Herschel imaging of 61 Vir: implications for the prevalence of debris in low-mass planetary systems
Ivison, R. J.; Bryden, G.; Kavelaars, J. J. +15 more
This paper describes Herschel observations of the nearby (8.5 pc) G5V multi-exoplanet host star 61 Vir at 70, 100, 160, 250, 350 and 500 ?m carried out as part of the DEBRIS survey. These observations reveal emission that is significantly extended out to a distance of >15 arcsec with a morphology that can be fitted by a nearly edge-on (77° incl…