892 research outputs found
Spectral energy distributions of quasars selected in the mid-infrared
We present preliminary results on fitting of SEDs to 142 z>1 quasars selected
in the mid-infrared. Our quasar selection finds objects ranging in extinction
from highly obscured, type-2 quasars, through more lightly reddened type-1
quasars and normal type-1s. We find a weak tendency for the objects with the
highest far-infrared emission to be obscured quasars, but no bulk systematic
offset between the far-infrared properties of dusty and normal quasars as might
be expected in the most naive evolutionary schemes. The hosts of the type-2
quasars have stellar masses comparable to those of radio galaxies at similar
redshifts. Many of the type-1s, and possibly one of the type-2s require a very
hot dust component in addition to the normal torus emission.Comment: 4 pages, 2 figures, to appear in the proceedings of The Spectral
Energy Distribution of Galaxies, Preston, September 2011, eds R.J. Tuffs &
C.C. Popesc
The influence of gibberellic acid and paclobutrazol on induction of somatic embryogenesis in wild type and hairy root cultures of Centaurium erythraea Gillib.
The effects of exogenous gibberellic acid (GA3) and paclobutrazol on induction of somatic embryos in wild type and hairy root culture of Centaurium erythraea Gillib. were investigated. Both compoundswere incorperated into 1/2 MS medium at 6 concentrations (0.01, 0.03, 0.1, 0.3, 1.0 and 3.0 ìM). Wild type root and hairy root explants cultured in the presence of GA3 at all tested concentrations under 16-h photoperiod or in the darkness decreased the number of somatic embryos that were produced. Paclobutrazol (0.3 mM) induced the largest number (19.7, 16.5) of somatic embryos in wild type and hairy root cultures, respectively. Rooting of plants derived from somatic embryos as achieved on ½MSmedium. These results indicate that paclobutrazol is beneficial for somatic embryo induction and formation in wild type and hairy root culture
The location of an active nucleus and a shadow of a tidal tail in the ULIRG Mrk 273
Analysis of data from the Chandra X-ray Observatory for the double nucleus ULIRG Mrk 273 reveals an absorbed hard X-ray source coincident with the southwest nucleus, implying that this unresolved, near-infrared source is where an active nucleus resides, while the northern nuclear region contains a powerful starburst that dominates the far infrared luminosity. There is evidence of a slight image extension in the 6–7 keV band, where an Fe K line is present, towards the northern nucleus. A large-scale, diffuse emission nebula detected in soft X-rays contains a dark lane that spatially coincides with a high surface-brightness tidal tail extending ~50 arcsec (40 kpc) to the south. The soft X-ray source is likely located behind the tidal tail, which absorbs X-ray photons along the line of sight. The estimated column density of cold gas in the tidal tail responsible for shadowing the soft X-rays is N_H ≥ 6 × 10^(21) cm^(-2), consistent with the tidal tail having an edge-on orientation
A subarcsecond near-infrared view of massive galaxies at z > 1 with Gemini Multiconjugate Adaptive Optics
We present images taken using the Gemini South Adaptive Optics Imager (GSAOI)
with the Gemini Multiconjugate Adaptive Optics System (GeMS) in three 2
arcmin fields in the Spitzer Extragalactic Representative Volume Survey.
These GeMS/GSAOI observations are among the first resolution
data in the near-infrared spanning extragalactic fields exceeding
in size. We use these data to estimate galaxy sizes, obtaining
results similar to those from studies with the Hubble Space Telescope, though
we find a higher fraction of compact star forming galaxies at . To
disentangle the star-forming galaxies from active galactic nuclei (AGN), we use
multiwavelength data from surveys in the optical and infrared, including
far-infrared data from Herschel, as well as new radio continuum data from the
Australia Telescope Compact Array and Very Large Array. We identify
ultraluminous infrared galaxies (ULIRGs) at , which consist of a
combination of pure starburst galaxies and Active Galactic Nuclei
(AGN)/starburst composites. The ULIRGs show signs of recent merger activity,
such as highly disturbed morphologies and include a rare candidate triple AGN.
We find that AGN tend to reside in hosts with smaller scale sizes than purely
star-forming galaxies of similar infrared luminosity. Our observations
demonstrate the potential for MCAO to complement the deeper galaxy surveys to
be made with the James Webb Space Telescope.Comment: 20 pages, AJ, in pres
Influence of liquefied and CCB containing liquefied wood on growth of wood decay fungi
There are high amounts of post-consumed protected waste wood removed from service every year. The residual biocides, including copper, chromium and boron from CCB (Cu, Cr, B) in post-consumed wood that was protected with biocides may cause environmental problems during waste management, for example during land filling. Therefore, the aim of this study was to find out if Cu and Cr in the processed waste wood, previously treated with CCB, can be re-used as a wood preservative or in coatings made of liquefied wood. Liquefaction of CCB containing waste wood could be as well the first step in the elimination process of metals. So, the optimal conditions for liquefaction of CCB (Cu, Cr and B) containing black poplar (Populus nigra L.) wood were established and compared with liquefaction of uncontaminated black poplar wood. The reactants for liquefaction of black poplar wood sawdust were ethylene glycol (EG) and sulphuric acid. It was observed that in the last stages of the liquefaction process, the presence of Cu, Cr and B did not have any influence on liquefaction yield (LY), while their influence was observed in first stages of the solvolytic reaction. Investigations of fungicidal properties of uncontaminated and CCB containing liquefied wood showed higher antifungal efficacy of liquefied wood without Cu, Cr and B than of liquefied wood that contained CCB. In the tested concentration range, the presence of Cu even promoted the growth of selected wood decay fungi. One of the reasons for higher toxicity of liquefied black poplar sawdust without Cu, Cr and B, was its very low pH value
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