3,831 research outputs found
The evolution of AGN activity in brightest cluster galaxies
ArtĂculo escrito por un elevado nĂșmero de autores, solo se referencian el que aparece en primer lugar, el nombre del grupo de colaboraciĂłn, si le hubiere, y los autores pertenecientes a la UAMWe present the results of an analysis of Wide-field Infrared Survey Explorer (WISE) observations of the full 2500 deg2 South Pole Telescope (SPT)-Sunyaev-Zel'dovich cluster sample. We describe a process for identifying active galactic nuclei (AGN) in brightest cluster galaxies (BCGs) based on WISE mid-IR color and redshift. Applying this technique to the BCGs of the SPT-SZ sample, we calculate the AGN-hosting BCG fraction, which is defined as the fraction of BCGs hosting bright central AGNs over all possible BCGs. Assuming an evolving single-burst stellar population model, we find statistically significant evidence (>99.9%) for a mid-IR excess at high redshift compared to low redshift, suggesting that the fraction of AGN-hosting BCGs increases with redshift over the range of 0 1. Last, this work confirms that the runaway cooling phase, as predicted by the classical cooling-flow model, in the Phoenix cluster is extremely rare and most BCGs have low (relative to Eddington) black hole accretion rate
Lessons learned from the two largest Galaxy morphological classification catalogues built by convolutional neural networks
ArtĂculo escrito por un elevado nĂșmero de autores, solo se referencian el que aparece en primer lugar, los autores pertenecientes a la UAM y el nombre del grupo de colaboraciĂłn, si lo hubiereThis is an electronic version of an article published in Monthly Notices of the Royal Astronomical Society. T. Y. Cheng, H. DomĂnguez SĂĄnchez, J. Vega-Ferrero, C. J. Conselice, M. Siudek, A. AragĂłn-Salamanca, M. Bernardi, R. Cooke, L. Ferreira, M. Huertas-Company , J. Krywult, A. Palmese , A. Pieres , A. A. Plazas MalagĂłn, A. Carnero Rosell , D. Gruen, D. Thomas , D. Bacon, D. Brooks, D. J. James, D. L. Hollowood, D. Friedel, E. Suchyta, E. SĂĄnchez, F. Menanteau, F. Paz-ChinchĂłn, G. GutiĂ©rrez, G. Tarle, I. Sevilla-Noarbe, I. Ferrero, J. Annis, J. Frieman, J. GarcĂa-Bellido, J. Mena-FernĂĄndez, K. Honscheid, K. Kuehn, L. N. da Costa, M. Gatti, M. Raveri, M. E. S. Pereira, M. RodrĂguez-Monroy, M. Smith, M. Carrasco Kind, M. Aguena, M. E. C. Swanson, N. Weaverdyck, P. Doel, R. Miquel, R. L. C. Ogando, R. A. Gruendl, S. Allam, S. R. Hinton, S. Dodelson, S. Bocquet, S. Desai, S. Everett and V. Scarpine in âLessons learned from the two largest Galaxy morphological classification catalogues built by convolutional neural networksâ. Monthly Notices of the Royal Astronomical Society 518.2 (2023): 2794-2809We compare the two largest galaxy morphology catalogues, which separate early- and late-type galaxies at intermediate redshift. The two catalogues were built by applying supervised deep learning (convolutional neural networks, CNNs) to the Dark Energy Survey data down to a magnitude limit of âŒ21 mag. The methodologies used for the construction of the catalogues include differences such as the cutout sizes, the labels used for training, and the input to the CNN â monochromatic images versus gri-band normalized images. In addition, one catalogue is trained using bright galaxies observed with DES (i 19, the overall agreement is good (âŒ95 per cent), but is mostly driven by the large spiral fraction in the two catalogues. In contrast, the agreement within the elliptical population is not as good, especially at faint magnitudes. By studying the mismatched cases, we are able to identify lenticular galaxies (at least up to i < 19), which are difficult to distinguish using standard classification approaches. The synergy of both catalogues provides an unique opportunity to select a population of unusual galaxie
On the heterochromatic number of hypergraphs associated to geometric graphs and to matroids
The heterochromatic number hc(H) of a non-empty hypergraph H is the smallest
integer k such that for every colouring of the vertices of H with exactly k
colours, there is a hyperedge of H all of whose vertices have different
colours. We denote by nu(H) the number of vertices of H and by tau(H) the size
of the smallest set containing at least two vertices of each hyperedge of H.
For a complete geometric graph G with n > 2 vertices let H = H(G) be the
hypergraph whose vertices are the edges of G and whose hyperedges are the edge
sets of plane spanning trees of G. We prove that if G has at most one interior
vertex, then hc(H) = nu(H) - tau(H) + 2. We also show that hc(H) = nu(H) -
tau(H) + 2 whenever H is a hypergraph with vertex set and hyperedge set given
by the ground set and the bases of a matroid, respectively
Recommendations and guidelines for applied nutrition experiments in rabbits
[EN] The aim of this paper was to draw up a set of recommendations for applied nutrition and feeding trials with rabbits, in relation to certain aspects such as determining the nutritive value of raw materials or diets in growing or reproducing animals, studying digestive physiology and obtaining growth and reproduction parameters. We deal first with animals, size of the sample, housing conditions, diets, handling, measurements, and the data analyses relevant to the design of the experiment are described. Secondly, we give a list of recommended items and include some comments.This study was partly supported by the EUROPEAN COMMISSION (ERAFE program and the COST 848 Action).FernĂĄndez-Carmona, J.; Blas, E.; Pascual AmorĂłs, JJ.; Maertens, L.; Gidenne, T.; Xiccato, G.; GarcĂa, J. (2005). Recommendations and guidelines for applied nutrition experiments in rabbits. World Rabbit Science. 13. doi:10.4995/wrs.2005.516SWORD1
Where Should My Child Go to School? Parent and Child Considerations in Binational Families
Using examples encountered from our multi-year study of students encountered in Mexican schools with prior experience in US schools, we look at transnationally-tied familiesâ decision-making regarding where to send their children to school and ask whether parents should âparent from afarâ. We donât pose that as a question about idealsâ what would be best if parents had economic security and unambiguous legal residential statusâ but rather as a more pragmatic one. Given some parentsâ and childrenâs limited agency in real- world circumstances, what is their best path forward
Identifying the Anthropological in a Mixed- Methods Study of Transnational Students in Mexican Schools
Identifying surveying as more commonly sociological and semistructured interviewing as more commonly anthropological, which describes disciplinary histories more than any fixed formulas, we juxtapose transnational studentsâ survey answers collected in Mexican schools with their answers to interviewers several months later. From this, we consider what can be learned about research methodology and transnational student cosmology when different methods yield discrepant answers. Without claiming superiority for either mechanism, we find their combination illuminating, and it substantiates the claim that anthropological inquiry can add crucial value to mixed-methods, interdisciplinary inquiry
On the Number of Factorizations of an Element in an Atomic Monoid
Let S be a reduced commutative cancellative atomic monoid. If s is a nonzero element of S, then we explore problems related to the computation of η(s), which represents the number of distinct irreducible factorizations of sâS. In particular, if S is a saturated submonoid of Nd, then we provide an algorithm for computing the positive integer r(s) for which
0 \u3c limnââη(sn)nr(s)-1â.
We further show that r(s) is constant on the Archimedean components of S. We apply the algorithm to show how to compute
limnââη(sn)nr(s)-1
and also consider various stability conditions studied earlier for Krull monoids with finite divisor class group
STRIDES: automated uniform models for 30 quadruply imaged quasars
This is an electronic version of an article published in Monthly Notices of the Royal Astronomical Society. T Schmidt et al. in âSTRIDES: automated uniform models for 30 quadruply imaged quasarsâ. Monthly Notices of the Royal Astronomical Society 518.1 (2023): 1260-1300ArtĂculo escrito por un elevado nĂșmero de autores, solo se referencian el que aparece en primer lugar, los autores pertenecientes a la UAM y el nombre del grupo de colaboraciĂłn, si lo hubiereGravitational time delays provide a powerful one-step measurement of H0, independent of all other probes. One key ingredient in time-delay cosmography are high-accuracy lens models. Those are currently expensive to obtain, both, in terms of computing and investigator time (105â106 CPU hours and âŒ0.5â1 yr, respectively). Major improvements in modelling speed are therefore necessary to exploit the large number of lenses that are forecast to be discovered over the current decade. In order to bypass this roadblock, we develop an automated modelling pipeline and apply it to a sample of 31 lens systems, observed by the Hubble Space Telescope in multiple bands. Our automated pipeline can derive models for 30/31 lenses with few hours of human time and <100 CPU hours of computing time for a typical system. For each lens, we provide measurements of key parameters and predictions of magnification as well as time delays for the multiple images. We characterize the cosmography-readiness of our models using the stability of differences in the Fermat potential (proportional to time delay) with respect to modelling choices. We find that for 10/30 lenses, our models are cosmography or nearly cosmography grade (<3 perâcent and 3â5 perâcent variations). For 6/30 lenses, the models are close to cosmography grade (5â10 perâcent). These results utilize informative priors and will need to be confirmed by further analysis. However, they are also likely to improve by extending the pipeline modelling sequence and options. In conclusion, we show that uniform cosmography grade modelling of large strong lens samples is within reac
Students We Share Are Also in Puebla, Mexico: Preliminary Findings from a 2009â2010 Survey
Increasingly, emigrants from Mexico to the United States are taking their children with them when they migrate. Additionally, children born to Mexican parents living in the United States may have dual US and Mexican citizenship. Later their parents may return to Mexico with their children who have now learned English and adapted to the US way of life. The US Supreme Court decision Plyler v. Doe allows undocumented children living in the United States to attend US public schools through grade twelve, which means that when their immigrant parents return to Mexico or send their children back to Mexico to live with relatives, the children may have spent several years in US schools and may be unfamiliar with Mexican educational programs. Depending on their age and time in the United States, they may have been taught entirely in English and may be lacking in academic Spanish-language skills. Their return to Mexico creates demands in Mexican schools to identify those students and determine how to incorporate them into the Mexican educational system. This includes providing Spanish-language instruction and a national curriculum that varies significantly from the US instructional program. This chapter explores the effects on the Mexican educational system of the increasing numbers of these transnational students who have experienced schooling in both the United States and Mexico and presents data showing where they are concentrated in Mexico
Dark Energy Survey year 1 results: Constraints on extended cosmological models from galaxy clustering and weak lensing
ArtĂculo escrito por un elevado nĂșmero de autores, solo se referencian el que aparece en primer lugar, el nombre del grupo de colaboraciĂłn, si le hubiere, y los autores pertenecientes a la UA
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