Composition and diversity of spring-active carabid beetle assemblages in relation to soil management in organic wheat fields in Denmark

Patterns in spring-active carabid assemblages were described in relation to four organic soil management regimes (no soil nutrient addition, undersowing, animal manure, undersowing + manure) in two areas of Denmark. On the island of Zealand, the Flakkebjerg study area had 22 species, 3-10 species/trap, and the species rank of these was the same for all treatments. The dominant species were Pterostichus melanarius, Agonum dorsale, Harpalus rufipes and Calathus fuscipes. At Foulum, Jutland, there were 46 species, 12-15 species/ trap, dominated by P. versicolor, P. melanarius, A. dorsale and Nebria brevicollis. Their rank, however, was not the same for all treatments. There were remarkable differences in the carabid assemblages of the two sites, and manure addition modified the assemblages, more pronouncedly so in the poorer-soil Flakkebjerg site. However, we did not detect clear effects of the studied treatments on carabid species richness, overall abundance or Pterostichus melanarius alone

Galaxy pairs as a probe for mergers at z ~ 2

In this work I investigate the redshift evolution of pair fraction of a sample of 196 massive galaxies from z = 0 to 3, selected from the COSMOS field. We find that on average a massive galaxy undergoes ~ 1.1 \pm 0.5 major merger since z = 3. I will review the current limitations of using the pair fraction as a probe for quantifying the impact of mergers on galaxy evolution. This work is based on the paper Man et al. (2011).Comment: 4 pages; to appear on the Conference Proceedings for "Galaxy Mergers in an Evolving Universe", held in Hualien, Taiwan (October 2011

X-ray Emission from Haloes of Simulated Disc Galaxies

Bolometric and 0.2-2 keV X-ray luminosities of the hot gas haloes of simulated disc galaxies have been calculated at redshift z=0. The TreeSPH simulations are fully cosmological and the sample of 44 disc galaxies span a range in characteristic circular speeds of V_c = 130-325 km/s. The galaxies have been obtained in simulations with a considerable range of physical parameters, varying the baryonic fraction, the gas metallicity, the meta-galactic UV field, the cosmology, the dark matter type, and also the numerical resolution. The models are found to be in agreement with the (few) relevant X-ray observations available at present. The amount of hot gas in the haloes is also consistent with constraints from pulsar dispersion measures in the Milky Way. Forthcoming XMM and Chandra observations should enable much more stringent tests and provide constraints on the physical parameters. We find that simple cooling flow models over-predict X-ray luminosities by up to two orders of magnitude for high (but still realistic) cooling efficiencies relative to the models presented here. Our results display a clear trend that increasing cooling efficiency leads to decreasing X-ray luminosities at z=0. The reason is found to be that increased cooling efficiency leads to a decreased fraction of hot gas relative to total baryonic mass inside of the virial radius at present. At gas metal abundances of a third solar this hot gas fraction becomes as low as just a few percent. We also find that most of the X-ray emission comes from the inner parts (inner about 20 kpc) of the hot galactic haloes. Finally, we find for realistic choices of the physical parameters that disc galaxy haloes possibly were more than one order of magnitude brighter in soft X-ray emission at z=1, than at present.Comment: 8 pages, 7 figures, MNRAS LaTeX forma

Thirty-fold: Extreme gravitational lensing of a quiescent galaxy at z=1.6z=1.6

We report the discovery of eMACSJ1341-QG-1, a quiescent galaxy at $z=1.594$ located behind the massive galaxy cluster eMACSJ1341.9$-$2442 ($z=0.835$). The system was identified as a gravitationally lensed triple image in Hubble Space Telescope images obtained as part of a snapshot survey of the most X-ray luminous galaxy clusters at $z>0.5$ and spectroscopically confirmed in ground-based follow-up observations with the ESO/X-Shooter spectrograph. From the constraints provided by the triple image, we derive a first, crude model of the mass distribution of the cluster lens, which predicts a gravitational amplification of a factor of $\sim$30 for the primary image and a factor of $\sim$6 for the remaining two images of the source, making eMACSJ1341-QG-1 by far the most strongly amplified quiescent galaxy discovered to date. Our discovery underlines the power of SNAPshot observations of massive, X-ray selected galaxy clusters for lensing-assisted studies of faint background populations

The size-star formation relation of massive galaxies at 1.5<z<2.5

We study the relation between size and star formation activity in a complete sample of 225 massive (M > 5 x 10^10 Msun) galaxies at 1.5<z<2.5, selected from the FIREWORKS UV-IR catalog of the CDFS. Based on stellar population synthesis model fits to the observed restframe UV-NIR SEDs, and independent MIPS 24 micron observations, 65% of galaxies are actively forming stars, while 35% are quiescent. Using sizes derived from 2D surface brightness profile fits to high resolution (FWHM_{PSF}~0.45 arcsec) groundbased ISAAC data, we confirm and improve the significance of the relation between star formation activity and compactness found in previous studies, using a large, complete mass-limited sample. At z~2, massive quiescent galaxies are significantly smaller than massive star forming galaxies, and a median factor of 0.34+/-0.02 smaller than galaxies of similar mass in the local universe. 13% of the quiescent galaxies are unresolved in the ISAAC data, corresponding to sizes <1 kpc, more than 5 times smaller than galaxies of similar mass locally. The quiescent galaxies span a Kormendy relation which, compared to the relation for local early types, is shifted to smaller sizes and brighter surface brightnesses and is incompatible with passive evolution. The progenitors of the quiescent galaxies, were likely dominated by highly concentrated, intense nuclear star bursts at z~3-4, in contrast to star forming galaxies at z~2 which are extended and dominated by distributed star formation.Comment: 6 pages, 4 figures, accepted for publication in Ap

Trace ideals for Fourier integral operators with non-smooth symbols II

We consider Fourier integral operators with symbols in modulation spaces and non-smooth phase functions whose second orders of derivatives belong to certain types of modulation space. We establish continuity and Schatten-von Neumann properties of such operators when acting on modulation spaces.Comment: 25 page