The evolution of galaxies and AGN from deep x-ray and optical surveys

Two complementary new surveys of the x-ray background (XRB), the WHDF and the 10 X 10 ks, are presented. 140 serendipitous x-ray hard and soft sources (S(_2)-10 keV 3. 10(^15); S0.5-2 keV 4 . 10(^16) ergcm(^2)s(^1) have been identified and characterised by conducting concurrent optical and x-ray observations. A principal aim of this work has been to establish whether x-ray luminous narrow-emission line galaxies (NELGs) are the sources that are the major contributors to the hard XRB, along with finding an explanation for their emission mechanisms. We build a case for a hidden AGN as the most likely explanation for such emission and, while NELGs are indeed found to be major contributors to the hard XRB, they are so as the nearby representatives of a major class of obscured AGN, most of which are too faint for probing with current spectroscopic facilities and appear either as "normal" galaxies or as blank fields in optical observations. In particular, we find no evidence of significant contribution from starbursts to the XRB intensity. We also explore the high-redshift population of luminous absorbed AGN and report on the discovery of a type QSO candidate at z = 2.12. But the number of such sources observed is found to be significantly below the predictions from obscured AGN models of the XRB and, inspired by the discovery of several broad-line quasars amongst the hardest sources in the WHDF and also in other surveys, we suggest that x-ray luminous absorbed AGN show optical broad lines more often than not. This affects the relationship between gas and dust in AGN and has direct consequences for the basic unification schemes for AGN. In a parallel program, not only to study how the stellar content of the present universe was assembled over time but also to understand the photometric properties of the galaxies that host an AGN, we perform detailed analysis of the evolutionary properties of early-type galaxies. We find that a significant fraction of colour-selected elliptical and lenticular galaxies in the direction of the WHDF show colours that are too blue to be consistent with the predictions of a simple mono-littiic collapse at high-redshift and passive evolution thereafter. Their large scatter in photometric observables seems to imply divergent histories and indicate that the early-type populations are rather heterogeneous. In particular, significant low-redshift star formation is deduced from the large scatter in their colour-magnitude relation and from the presence of [OII]ƛ3727 emission lines

Detection of irrigation inhomogeneities in an olive grove using the NDRE vegetation index obtained from UAV images

We have developed a simple photogrammetric method to identify heterogeneous areas of irrigated olive groves and vineyard crops using a commercial multispectral camera mounted on an unmanned aerial vehicle (UAV). By comparing NDVI, GNDVI, SAVI, and NDRE vegetation indices, we find that the latter shows irrigation irregularities in an olive grove not discernible with the other indices. This may render the NDRE as particularly useful to identify growth inhomogeneities in crops. Given the fact that few satellite detectors are sensible in the red-edge (RE) band and none with the spatial resolution offered by UAVs, this finding has the potential of turning UAVs into a local farmer’s favourite aid tool.Peer ReviewedPostprint (published version

Roughness induced variation as a new mechanism for hydrodynamic lubrication between parallel surfaces

This work proposes a new lift mechanism capable of explaining the hydrodynamic lift observed in real mechanical face seals with parallel surfaces. While it is well established that roughness is a key factor inducing such lift, its effect is commonly explained in the form of micro-wedges and asperity-level cavitation. The novelty of this work is to consider roughness induced random variability in the flow restriction, which induces effective wedges. First, a dedicated stochastic two-scale model is developed and used to demonstrate the proposed new mechanism in a case study. We demonstrate that the described new mechanism acts at scales comparable to the macroscopic size of the seal, much larger than the commonly considered micro-wedges. Afterwards, the limitations for this new proposed mechanism are discussed.Peer ReviewedPostprint (author's final draft

Tiedolliset vaikuttimet suunnitteluprosessissa : Kuosisuunnitelmia Nouki Designille

Opinnäytetyö tutkii kuosin suunnittelun käytännön vaiheita vaatetusbrändi NOUKIlle. Lähtökohta opinnäytetyöhön oli tekijän oma kiinnostus kuosisuunnitteluun. Työssä tutkittiin suunnittelutyön taustalla vaikuttavia tietoisia ja tiedostamattomia tiedon elementtejä. Työn tavoitteena oli lisätä ymmärrystä suunnittelijan sisäisestä tiedon keräämisestä, käyttämisestä ja jäsentämisestä sekä vuorovaikutteisen tiedon synnystä suunnitteluprosessissa. Näistä tiedoista hyötyvät sekä suunnittelija että asiakas. Käytännön kuosin suunnittelua asiakasyritykselle työssä lähestyttiin suunnittelijan lähtökohdista käsin. Suunnittelutehtävä hahmotetaan prosessina, jossa lopputulos on asiakkaan näköinen, joskaan ei suunnittelullisesti asiakkaasta lähtevä. Työssä tutkittiin asiakkaan brändiä ja brändiymmärrystä. Lähteenä asiakasymmärtämisen lisäämiseksi käytettiin keskusteluja asiakasyrityksen kanssa, internetlähteitä sekä sähköpostihaastattelua ja omaa havainnointia. Työssä tutkittiin tietämisen lajien ilmenemistä ja vaikuttamista suunnitteluprosessissa. Työn tuloksissa esitellään yksinkertainen malli tiedon ja suunnitteluprosessin suhteesta. Työn johtopäätöksenä voidaan todeta, että suunnittelutyön tiedolliset vaikuttimet ovat moninaiset. Suunnittelijan kykyyn ymmärtää brändiä ja asiakasta vaikuttavat henkilökohtaiset näkyvät ja näkymättömät tiedolliset lähtökohdat.Osia työstä on pidetty salaisena toimeksiantajan pyynnöstä

Completion of the GOYA photometric survey

The Galaxy Origins and Young Assembly (goya) survey is designed to study the formation and evolution of 1 < z < 3 galaxies with the aim of learning on the epoch and the mechanisms by which galaxies assembled the bulk of their stars and acquired their present structure and dynamics. In 1998 goya proposed, and has since been guiding, the construction of the most ambitious of the common-user instruments for GranTeCan —the emir near-infrared multi-object spectrograph. In preparation for the exploitation of emir, we have conducted a deep near-infrared photometric survey, for sample selection and characterisation. Now that this research has reached its final stages, we provide here details on its current status and its finalisation plans. Overall, this survey has images of 0.5 square degrees of high-latitude sky to limiting ab magnitude Ks = 23.7 (5-¾, 100 aperture) and corresponding depths at U,B, V,R, I and J. The sample of sources obtained is being extended to include fields available to Gemini-S, since a recent collaboration with the Flamingos-2 Early Science Survey Team grants goya privileged access to this pioneering near-infrared multi-object spectrograph.Peer ReviewedPostprint (published version

EMIR, the GTC NIR multi-object imager-spectrograph

EMIR, currently entering into its fabrication and AIV phase, will be one of the first common user instruments for the GTC, the 10 meter telescope under construction by GRANTECAN at the Roque de los Muchachos Observatory (Canary Islands, Spain). EMIR is being built by a Consortium of Spanish and French institutes led by the Instituto de Astrofísica de Canarias (IAC). EMIR is designed to realize one of the central goals of 10m class telescopes, allowing observers to obtain spectra for large numbers of faint sources in a time-efficient manner. EMIR is primarily designed to be operated as a MOS in the K band, but others a wide range of observing modes, including imaging and spectroscopy, both long slit and multi-object, in the wavelength range 0.9 to 2.5 um. It is equipped with two innovative subsystems: a robotic reconfigurable multi-slit mask and dispersive elements formed by the combination of high quality distraction grating and conventional prisms, both at the heart of the instrument. The present status of development, expected performances, schedule and plans for scientific exploitation are described and discussed. The development and fabrication of EMIR is funded by GRANTECAN and the Plan Nacional de Astronomía y Astrofísica (National Plan for Astronomy and Astrophysics, Spain).Peer ReviewedPostprint (published version

EAST: The EMIR associated science team

EMIR Associate Science Team (EAST) is a scientific group in charge of developing an observing program complemen tary to that of GOYA, which might serve as a testing bed for all the kinds of science that EMIR can do. Hence EAST puts the emphasis on developing proposals which will exploit the most diverse capabilities of the spectrograph

Evolució de la llei del soroll de transport a Anglaterra

Peer ReviewedPostprint (published version

Identification of a set of variables for the classification of páramo soils using a nonparametric model, remote sensing, and organic carbon

Páramo ecosystems harbor important biodiversity and provide essential environmental services such as water regulation and carbon sequestration. Unfortunately, the scarcity of information on their land uses makes it difficult to generate sustainable strategies for their conservation. The purpose of this study is to develop a methodology to easily monitor and document the conservation status, degradation rates, and land use changes in the páramo. We analyzed the performance of two nonparametric models (the CART decision tree, CDT, and multivariate adaptive regression curves, MARS) in the páramos of the Chambo sub-basin (Ecuador). We used three types of attributes: digital elevation model (DEM), land use cover (Sentinel 2), and organic carbon content (Global Soil Organic Carbon Map data, GSOC) and a categorical variable, land use. We obtained a set of selected variables which perform well with both models, and which let us monitor the land uses of the páramos. Comparing our results with the last report of the Ecuadorian Ministry of Environment (2012), we found that 9% of the páramo has been lost in the last 8 years.Peer ReviewedPostprint (published version

The XMM-Newton/2dF survey - II. The nature of X-ray-faint optically bright X-ray sources

In this paper we investigate the properties of low X-ray-to-optical flux ratio sources detected in a wide area (2.5deg^2) shallow (f(0.5-8keV)~10e-14cgs) XMM-Newton survey. We find a total of 26 sources (5% of the total X-ray selected population) with log f_X/f_{opt}<-0.9 to the above flux limit. Optical spectroscopy is available for 20 of these low X-ray-to-optical flux ratio objects. Most of them are found to be associated with Galactic stars (total of 8) and broad line AGNs (total of 8).We also find two sources with optical spectra showing absorption and/or narrow emission lines and X-ray/optical properties suggesting AGN activity. Another two sources are found to be associated with low redshift galaxies with narrow emission line optical spectra, X-ray luminosities L_X(0.5-8keV)~10e41cgs and logf_X/f_opt ~ -2 suggesting `normal' star-forming galaxies. Despite the small number statistics the sky density of `normal' X-ray selected star-forming galaxies at the flux limit of the present sample is low consistent with previous ROSAT HRI deep surveys. Also, the number density estimated here is in good agreement with both the logN-logS of `normal' galaxies in the Chandra Deep Field North (extrapolated to bright fluxes) and model predictions based on the X-ray luminosity function of local star-forming galaxies.Peer Reviewe