574 research outputs found
Wide-field mid-infrared and millimetre imaging of the high-redshift radio galaxy, 4C41.17
We present deep 350- and 1200-micron imaging of the region around 4C41.17 --
one of the most distant (z = 3.792) and luminous known radio galaxies --
obtained with the Submillimeter High Angular Resolution Camera (SHARC-II) and
the Max Planck Millimeter Bolometer Array (MAMBO). The radio galaxy is robustly
detected at 350- and 1200-micron, as are two nearby 850-micron-selected
galaxies; a third 850-micron source is detected at 350-micron and coincides
with a ~ 2-sigma feature in the 1200-micron map. Further away from the radio
galaxy an additional nine sources are detected at 1200-micron, bringing the
total number of detected (sub)millimeter selected galaxies (SMGs) in this field
to 14. Using radio images from the Very Large Array (VLA) and Spitzer
mid-infrared (mid-IR) data, we find statistically robust radio and/or 24-micron
counterparts to eight of the 14 SMGs in the field around 4C41.17. Follow-up
spectroscopy with Keck/LRIS has yielded redshifts for three of the eight
robustly identified SMGs, placing them in the redshift range 0.5 < z < 2.7,
i.e. well below that of 4C41.17. We infer photometric redshifts for a further
four sources using their 1.6-micron (rest-frame) stellar feature as probed by
the IRAC bands; only one of them is likely to be at the same redshift as
4C41.17. Thus at least four, and as many as seven, of the SMGs within the
4C41.17 field are physically unrelated to the radio galaxy. With the redshift
information at hand we are able to constrain the observed over-densities of
SMGs within radial bins stretching to R=50 and 100" (~ 0.4 and ~ 0.8Mpc at z ~
3.8) from the radio galaxy to ~ 5x and ~ 2x that of the field, dropping off to
the background value at R=150". [Abridged]Comment: 20 pages, 9 figures, accepted for publication in MNRA
Kinematics of the Young Stellar Objects associated with the Cometary Globules in the Gum Nebula
An analysis of proper motion measurements of the Young Stellar Objects (YSOs)
associated with the Cometary Globules (CGs) in the Gum Nebula is presented.
While earlier studies based on the radial velocity measurements of the CGs
suggested expansion of the system of the CGs, the observed proper motion of the
YSOs shows no evidence for expansion. In particular the kinematics of two YSOs
embedded in CGs is inconsistent with the supernova explosion of the companion
of Pup about 1.5 Myr ago as the cause of the expansion of the CG
system. YSOs associated with the CGs share the average proper motion of the
member stars of the Vela OB2 association. A few YSOs that have relatively large
proper motions are found to show relatively low infrared excesses.Comment: 19 pages, 6 figures, 4 tables, Accepted for publication in MNRA
Tecnologia de produção de vinagre de mel.
Com a perspectiva de diversificação dos produtos derivados do mel, este trabalho teve como finalidade avaliar a produção de vinagre de mel de abelhas africanizadas (Apis mellifera L.). A produção do vinagre foi realizada através da fermentação acética de hidromel com teor alcoólico de 8% (v/v), obtido a partir de um mosto com 17,11% (m/v) de açúcares totais. A fermentação acética foi realizada pelo método rápido, em fermentador vertical com capacidade de 15 litros, utilizando vinagre forte não pasteurizado como inóculo, por 72 horas. Durante esta fermentação foram monitoradas as temperaturas interna (fermentador) e ambiente. O vinagre obtido apresentou acidez em torno de 9% e teor alcoólico em torno de 1% (v/v). O rendimento da fermentação acética foi entre 91,2 e 97,17%. O produto final foi diluído de acordo com a legislação brasileira (4,0% de acidez) e analisado sensorialmente, demonstrando ser de boa aceitabilidade Os teores de álcool etílico, ácido acético, resíduo mineral fixo e resíduo seco a 105oC foram de 0,32%; 4,2%; 0,05% e 1,76%, respectivamente. A análise microscópica revelou ausência de sujidades, larvas e parasitas.bitstream/CPAP-2009-09/57063/1/BP86.pd
The faint counterparts of MAMBO mm sources near the NTT Deep Field
We discuss identifications for 18 sources from our MAMBO 1.2mm survey of the
region surrounding the NTT Deep Field. We have obtained accurate positions from
Very Large Array 1.4GHz interferometry and in a few cases IRAM mm
interferometry, and have also made deep BVRIzJK imaging at ESO. We find
thirteen 1.2mm sources associated with optical/near-infrared objects in the
magnitude range K=19.0 to 22.5, while five are blank fields at K>22. The median
redshift of the radio-identified mm sources is ~2.6 from the radio/mm
estimator, and the median optical/near-infrared photometric redshifts for the
objects with counterparts ~2.1. This suggests that those radio-identified mm
sources without optical/near-infrared counterparts tend to lie at higher
redshifts than those with optical/near-infrared counterparts. Compared to
published identifications of objects from 850micron surveys of similar depth,
the median K and I magnitudes of our counterparts are roughly two magnitudes
fainter and the dispersion of I-K colors is less. Real differences in the
median redshifts, residual mis-identifications with bright objects, cosmic
variance, and small number statistics are likely to contribute to this
significant difference, which also affects redshift measurement strategies. We
discuss basic properties of the near-infrared/(sub)mm/radio spectral energy
distributions of our galaxies and of interferometrically identified submm
sources from the literature. From a comparison with submm objects with
CO-confirmed spectroscopic redshifts we argue that roughly two thirds of the
(sub)mm galaxies are at z>~2.5. This fraction is probably larger when including
sources without radio counterparts. (abridged)Comment: 45 pages, 9 figures. Accepted by ApJ. The resolution of figures 2 and
3 has been degraded. A higher quality pdf version of this paper is available
at http://www.mpe.mpg.de/~dannerb
Genesis and evolution of dust in galaxies in the early Universe I. Modeling dust evolution in starburst galaxies
We have developed a numerical galactic chemical evolution model. The model is
constructed such that the effect of a wide range of parameters can be
investigated. It takes into account results from stellar evolution models, a
differentiation between diverse types of core collapse SNe and the contribution
of AGB stars in the mass range 3-8 Msun. We consider the lifetime-dependent
yield injection into the ISM by all sources as well as dust destruction due to
SN shocks in the ISM. We ascertain the temporal progression of the dust mass,
the dust-to-gas and dust-to-metal mass ratios as well as other physical
properties of a galaxy and study their dependence on the mass of the galaxy,
the IMF, dust production efficiencies and dust destruction in the ISM. The
amount of dust and the physical properties of a galaxy strongly depend on the
initial gas mass available. Overall, while the total amount of dust produced
increases with galaxy mass, the detailed outcome depends on the SN dust
production efficiency, the IMF and the strength of dust destruction in the ISM.
Dust masses are higher for IMFs biased towards higher stellar masses, despite
the fact that these IMFs are more strongly affected by dust destruction in the
ISM. The sensitivity to the IMF increases as the mass of the galaxy decreases.
SNe are primarily responsible for a significant enrichment with dust at early
epochs (< 200 Myr). Dust production with a dominant contribution by AGB stars
is found to be insufficient to account for dust masses in excess of 10^8 Msun
within 400 Myr after starburst. We find that galaxies with initial gas masses
between 1-5 x 10^11 Msun are sufficiently massive to enable production of dust
masses >10^8 Msun. Our preferred scenario is dominated by SN dust production in
combination with top-heavy IMFs and moderate dust destruction in the ISM.Comment: 20 pages, 13 figures, 4 table
Herschel/PACS far-infrared photometry of two z>4 quasars
We present Herschel far-infrared (FIR) observations of two sub-mm bright
quasars at high redshift: SDSS J1148+5251 (z=6.42) and BR 1202-0725 (z=4.69)
obtained with the PACS instrument. Both objects are detected in the PACS
photometric bands. The Herschel measurements provide additional data points
that constrain the FIR spectral energy distributions (SEDs) of both sources,
and they emphasise a broad range of dust temperatures in these objects. For
lambda_rest ~< 20mu, the two SEDs are very similar to the average SEDs of
quasars at low redshift. In the FIR, however, both quasars show excess emission
compared to low-z QSO templates, most likely from cold dust powered by vigorous
star formation in the QSO host galaxies. For SDSS J1148+5251 we detect another
object at 160mu with a distance of ~10 arcseconds from the QSO. Although no
physical connection between the quasar and this object can be shown with the
available data, it could potentially confuse low-resolution measurements, thus
resulting in an overestimate of the FIR luminosity of the z=6.42 quasar.Comment: 4 pages, 3 figures, accepted for publication in the A&A special issue
on Hersche
Os verbos de julgamento em inglês e português: o que a análise contrastiva pode dizer sobre a Semântica de Frames
This paper discusses the boundaries of Frame Semantics for multilingual lexicon development. This is a contrastive study of verbs of judgment in English and Brazilian Portuguese using the parallel corpus COMPARA. The contrastive analysis of four lexical units, to accuse, to blame, to criticize and to praise places emphasis on points to be developed in order to create multilingual frame-based databases that are able to describe lexical meaning more broadly. The discussion of translation equivalents is important not only for translation studies, but also for multilingual lexicon development. Finding a proper translation equivalent is the fi rst step in the development of multilingual resources. This paper explores the complex meaning networks existing between languages when they are compared.Key words: Frame Semantics, verbs of judgment, contrastive linguistics.Este artigo tem como objetivo discutir os limites da Semântica de Frames na construção de léxicos multilíngues. Trata-se de um estudo contrastivo dos verbos de julgamento em inglês e português, variante brasileira, utilizando o COMPARA como corpus paralelo. Por meio de análise contrastiva de quatro verbos de julgamentos em inglês, to accuse, to blame, to criticize e to praise, abordam-se os pontos que podem ser desenvolvidos para a criação de bases de dados multilíngues que tenham como base teórica a Semântica de Frames, possibilitando uma melhor descrição do signifi cado lexical. A discussão acerca dos equivalentes de tradução, tradicionalmente abordada pelos estudos de tradução, é importante também para o desenvolvimento de recursos multilíngues, uma vez que o primeiro passo para o desenvolvimento desses recursos é, justamente, encontrar o equivalente de tradução apropriado. Assim, este estudo busca explorar as complexas redes de signifi cados existentes entre as línguas quando comparadas.Palavras-chave: Semântica de Frames, verbos de julgamento, linguística contrastiva
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