24 research outputs found
The COSMOS-WIRCam near-infrared imaging survey: I: BzK selected passive and star forming galaxy candidates at z>1.4
(abridged) We present a new near-infrared survey covering the 2 deg sq COSMOS
field. Combining our survey with Subaru B and z images we construct a deep,
wide-field optical-infrared catalogue. At Ks<23 (AB magnitudes) our survey
completeness is greater than 90% and 70% for stars and galaxies respectively
and contains 143,466 galaxies and 13,254 stars. At z~2 our catalogues contain
3931 quiescent and 25,757 star-forming BzK-selected galaxies representing the
largest and most secure sample of these objects to date. Our counts of
quiescent galaxies turns over at Ks~22 an effect which we demonstrate cannot be
due to sample incompleteness. In our survey both the number of faint and bright
quiescent objects exceeds the predictions of a semi-analytic galaxy formation
model, indicating potentially the need for further refinements in the amount of
merging and AGN feedback at z~2 in these models. We measure the angular
correlation function for each sample and find that at small scales the
correlation function for passive BzK galaxies exceeds the clustering of dark
matter. We use 30-band photometric redshifts to derive the spatial correlation
length and the redshift distributions for each object class. At Ks<22 we find
r_0^{\gamma/1.8}=7.0 +/-0.5h^{-1} Mpc for the passive BzK candidates and
4.7+/-0.8h^{-1} Mpc for the star-forming BzK galaxies. Our pBzK galaxies have
an average photometric redshift of z_p~1.4, in approximate agreement with the
limited spectroscopic information currently available. The stacked Ks image
will be made publicly available from IRSA.Comment: Accepted for publication in Astrophysical Journal. 17 pages, 17
figures, minor revisions to match published version available at
http://adsabs.harvard.edu/abs/2010ApJ...708..202
Spectroscopy of luminous z>7 galaxy candidates and sources of contamination in z>7 galaxy searches
We present three bright z+ dropout candidates selected from deep
Near-Infrared (NIR) imaging of the COSMOS 2 square degree field. All three
objects match the 0.8-8um colors of other published z>7 candidates but are
three magnitudes brighter, facilitating further study. Deep spectroscopy of two
of the candidates covering 0.64-1.02um with Keck-DEIMOS and all three covering
0.94-1.10um and 1.52-1.80um with Keck-NIRSPEC detects weak spectral features
tentatively identified as Ly-alpha at z=6.95 and z=7.69 in two of the objects.
The third object is placed at z~1.6 based on a 24um and weak optical detection.
A comparison with the spectral energy distributions of known z<7 galaxies,
including objects with strong spectral lines, large extinction, and large
systematic uncertainties in the photometry yields no objects with similar
colors. However, the lambda>1um properties of all three objects can be matched
to optically detected sources with photometric redshifts at z~1.8, so the
non-detection in the i+ and z+ bands are the primary factors which favors a z>7
solution. If any of these objects are at z~7 the bright end of the luminosity
function is significantly higher at z>7 than suggested by previous studies, but
consistent within the statistical uncertainty and the dark matter halo
distribution. If these objects are at low redshift, the Lyman-Break selection
must be contaminated by a previously unknown population of low redshift objects
with very strong breaks in their broad band spectral energy distributions and
blue NIR colors. The implications of this result on luminosity function
evolution at high redshift is discussed. We show that the primary limitation of
z>7 galaxy searches with broad filters is the depth of the available optical
data.Comment: 15 Pages, 15 figures, accepted to Ap
Spectroscopic Confirmation Of An Extreme Starburst At Redshift 4.547
We report the spectroscopic confirmation of a sub-mm galaxy (SMG) at z=4.547
with an estimated L_IR=0.5-2.0x10^13 L_sun. The spectra, mid-IR, and X-ray
properties indicate the bolometric luminosity is dominated by star formation at
a rate of >1000M_sun per yr. Multiple, spatially separated components are
visible in the Ly-Alpha line with an observed velocity difference of up to 380
km/sec and the object morphology indicates a merger. The best fit spectral
energy distribution and spectral line indicators suggest the object is 2-8 Myr
old and contains >10^10 M_sun of stellar mass. This object is a likely
progenitor for the massive early type systems seen at z~2.Comment: 4 pages, 4 figures, accepted to ApJ Letter
Pre-treatment and extraction techniques for recovery of added value compounds from wastes throughout the agri-food chain
The enormous quantity of food wastes discarded annually force to look for alternatives for this interesting feedstock. Thus, food bio-waste valorisation is one of the imperatives of the nowadays society. This review is the most comprehensive overview of currently existing technologies and processes in this field. It tackles classical and innovative physical, physico-chemical and chemical methods of food waste pre-treatment and extraction for recovery of added value compounds and detection by modern technologies and are an outcome of the COST Action EUBIS, TD1203 Food Waste Valorisation for Sustainable Chemicals, Materials and Fuels
Recommended from our members
Spectroscopic confirmation of an extreme starburst at redshift 4.547
We report the spectroscopic confirmation of a submillimeter galaxy (SMG) at z = 4.547 with an estimated LIR = (0.5-2.0) × 1013 L. The spectra, mid-IR, and X-ray properties indicate the bolometric luminosity is dominated by star formation at a rate of \u3e1000 M yr−1. Multiple, spatially separated components are visible in the Lyα line with an observed velocity difference of up to 380 km s−1 and the object morphology indicates a merger. The best-fit spectral energy distribution and spectral line indicators suggest the object is 2-8 Myr old and contains \u3e1010 M of stellar mass. This object is a likely progenitor for the massive early-type systems seen at z ~ 2
Recommended from our members
Spectroscopy of luminous z\u3e7 galaxy candidates and sources of contamination in z\u3e7 galaxy searches
We present three bright z+ dropout candidates selected from deep Near-Infrared (NIR) imaging of the COSMOS 2 square degree field. All three objects match the 0.8-8um colors of other published z\u3e7 candidates but are three magnitudes brighter, facilitating further study. Deep spectroscopy of two of the candidates covering 0.64-1.02um with Keck-DEIMOS and all three covering 0.94-1.10um and 1.52-1.80um with Keck-NIRSPEC detects weak spectral features tentatively identified as Ly-alpha at z=6.95 and z=7.69 in two of the objects. The third object is placed at z~1.6 based on a 24um and weak optical detection. A comparison with the spectral energy distributions of known z\u3c7 galaxies, including objects with strong spectral lines, large extinction, and large systematic uncertainties in the photometry yields no objects with similar colors. However, the lambda\u3e1um properties of all three objects can be matched to optically detected sources with photometric redshifts at z~1.8, so the non-detection in the i+ and z+ bands are the primary factors which favors a z\u3e7 solution. If any of these objects are at z~7 the bright end of the luminosity function is significantly higher at z\u3e7 than suggested by previous studies, but consistent within the statistical uncertainty and the dark matter halo distribution. If these objects are at low redshift, the Lyman-Break selection must be contaminated by a previously unknown population of low redshift objects with very strong breaks in their broad band spectral energy distributions and blue NIR colors. The implications of this result on luminosity function evolution at high redshift is discussed. We show that the primary limitation of z\u3e7 galaxy searches with broad filters is the depth of the available optical data
Fiji disease resistance in sugarcane: Relationship to cultivar preference in field populations of the planthopper vector Perkinsiella saccharicida
Populations of the planthopper vector Perkinsiella saccharicida on sugarcane cultivars resistant (cvs Q110 and Q87), moderately resistant (cvs Q90 and Q124) and susceptible (evs NCo310 and Q 102) to Fiji disease with known field resistance scores were monitored on the plant (2000-2001) and ratoon (2001-2002) crops. In both crops, the vector population remained very low, reaching its peak in the autumn. The vector population was significantly higher on cultivars susceptible to Fiji disease than on cultivars moderately resistant and resistant to Fiji disease. The number of R saccharicida adults, nymphs and oviposition sites per plant increased with the increase in the Fiji disease susceptibility. The results suggest that under low vector density, cultivar preference by the planthopper vector mediates Fiji disease resistance in sugarcane. To obtain resistance ratings in the glasshouse that reflect field resistance, glasshouse-screening trials should be conducted under both low and high vector densities, and the cultivar preference of the planthopper vector recorded along with Fiji disease incidence