2,459 research outputs found
A young stellar environment for the superluminous supernova PTF12dam
The progenitors of super luminous supernovae (SLSNe) are still a mystery.
Hydrogen-poor SLSN hosts are often highly star-forming dwarf galaxies and the
majority belongs to the class of extreme emission line galaxies hosting young
and highly star-forming stellar populations. Here we present a resolved
long-slit study of the host of the hydrogen-poor SLSN PTF12dam probing the kpc
environment of the SN site to determine the age of the progenitor. The galaxy
is a "tadpole" with uniform properties and the SN occurred in a star-forming
region in the head of the tadpole. The galaxy experienced a recent star-burst
superimposed on an underlying old stellar population. We measure a very young
stellar population at the SN site with an age of ~3 Myr and a metallicity of
12+log(O/H)=8.0 at the SN site but do not observe any WR features. The
progenitor of PTF12dam must have been a massive star of at least 60 M_solar and
one of the first stars exploding as a SN in this extremely young starburst.Comment: submitted to MNRAS letters. 5 pages, 3 figures, supplementary
material: 2 figures, 2 table
The host of the Type I SLSN 2017egm: A young, sub-solar metallicity environment in a massive spiral galaxy
Here we present an integral-field study of the massive, high-metallicity
spiral NGC 3191, the host of SN 2017egm, the closest SLSN Type I to date. We
use data from PMAS/CAHA and the public MaNGA survey to shed light on the
properties of the SLSN site and the origin of star-formation in this
non-starburst spiral galaxy. We map the physical properties different
\ion{H}{II} regions throughout the galaxy and characterize their stellar
populations using the STARLIGHT fitting code. Kinematical information allows to
study a possible interaction with its neighbouring galaxy as the origin of
recent star formation activity which could have caused the SLSN. NGC 3191 shows
intense star-formation in the western part with three large SF regions of low
metallicity. The central regions of the host have a higher metallicity, lower
specific star-formation rate and lower ionization. Modeling the stellar
populations gives a different picture: The SLSN region has two dominant stellar
populations with different ages, the youngest one with an age of 2-10 Myr and
lower metallicity, likely the population from which the SN progenitor
originated. Emission line kinematics of NGC 3191 show indications of
interaction with its neighbour MCG+08-19-017 at 45 kpc, which might be
responsible for the recent starburst. In fact, this galaxy pair has in total
hosted 4 SNe, 1988B (Type Ia), SN 2003ds (Type Ic in MCG+08-19-017), PTF10bgl
(SLSN-Type II) and 2017egm, underlying the enhanced SF in both galaxies due to
interaction. Our study shows that one has to be careful interpreting global
host and even gas properties without looking at the stellar population history
of the region. SLSNe seem to still be consistent with massive stars ( 20
M) requiring low () metallicity and those environments
can also occur in massive, late-type galaxies but not necessarily starbursts.Comment: Accepted for publication in A&A, 13 pages, 11 figures, 7 tables.
Abstract has been reduced to match arXiv form requirement
Development and validation of the scale of psychological abuse in intimate partner violence (EAPA-P)
Background: In the context of intimate partner violence, psychological abuse (PA) has progressively gained scientific relevance. Even so, a greater effort is needed to define and evaluate psychological intimate partner abuse. A new exhaustive and operative taxonomy of PA strategies leads to the contribution of a new evaluation instrument. Method: Participants were 101 women between 24 and 82 years old, who were abused by their partners and attended to in different municipal Catalan services, specialized in the topic. Results: The analyses have shown the suitability of a 19-item instrument divided into two factors: (1) direct PA strategies and (2) indirect PA strategies. The former includes strategies that affect the emotional, cognitive and behavioral dimension of the victim. The latter includes items that measure the amount of control and domination over the victimâs context. This scale has adequate psychometric properties in terms of score reliability and the validity of the relationship with other womenâs health variables. Conclusions: The EAPA-P, created based on a new definition and taxonomy of the forms of PA, is presented as a valid instrument to detect and measure intimate partner PA
Differential physiological responses of portuguese bread wheat (Triticum aestivum L.) genotypes under aluminium stress
Open Access JournalThe major limitation of cereal production in acidic soils is aluminium (Al) phytotoxicity which inhibits root growth. Recent evidence indicates that different genotypes within the same species have evolved different mechanisms to cope with this stress. With these facts in mind, root responses of two highly Al tolerant Portuguese bread wheat genotypesâBarbela 7/72/92 and Viloso moleâwere investigated along with check genotype Anahuac (Al sensitive), using different physiological and histochemical assays. All the assays confirmed that Barbela 7/72/92 is much more tolerant to Al phytotoxicity than Viloso Mole. Our results demonstrate that the greater tolerance to Al phytotoxicity in Barbela 7/72/92 than in Viloso Mole relies on numerous factors, including higher levels of organic acid (OAs) efflux, particularly citrate efflux. This might be associated with the lower accumulation of Al in the root tips, restricting the Al-induced lipid peroxidation and the consequent plasma membrane integrity loss, thus allowing better root regrowth under Al stress conditions. Furthermore, the presence of root hairs in Barbela 7/72/92 might also help to circumvent Al toxicity by facilitating a more efficient uptake of water and nutrients, particularly under Al stress on acid soils. In conclusion, our findings confirmed that Portuguese bread wheat genotype Barbela 7/72/92 represents an alternative source of Al tolerance in bread wheat and could potentially be used to improve the wheat productivity in acidic soils
The cosmic evolution of the spatially-resolved star formation rate and stellar mass of the CALIFA survey
We investigate the cosmic evolution of the absolute and specific star
formation rate (SFR, sSFR) of galaxies as derived from a spatially-resolved
study of the stellar populations in a set of 366 nearby galaxies from the
CALIFA survey. The analysis combines GALEX and SDSS images with the 4000 break,
H_beta, and [MgFe] indices measured from the datacubes, to constrain parametric
models for the SFH, which are then used to study the cosmic evolution of the
star formation rate density (SFRD), the sSFR, the main sequence of star
formation (MSSF), and the stellar mass density (SMD). A delayed-tau model,
provides the best results, in good agreement with those obtained from
cosmological surveys. Our main results from this model are: a) The time since
the onset of the star formation is larger in the inner regions than in the
outer ones, while tau is similar or smaller in the inner than in the outer
regions. b) The sSFR declines rapidly as the Universe evolves, and faster for
early than for late type galaxies, and for the inner than for the outer regions
of galaxies. c) SFRD and SMD agree well with results from cosmological surveys.
At z< 0.5, most star formation takes place in the outer regions of late spiral
galaxies, while at z>2 the inner regions of the progenitors of the current E
and S0 are the major contributors to SFRD. d) The inner regions of galaxies are
the major contributor to SMD at z> 0.5, growing their mass faster than the
outer regions, with a lookback time at 50% SMD of 9 and 6 Gyr for the inner and
outer regions. e) The MSSF follows a power-law at high redshift, with the slope
evolving with time, but always being sub-linear. f) In agreement with galaxy
surveys at different redshifts, the average SFH of CALIFA galaxies indicates
that galaxies grow their mass mainly in a mode that is well represented by a
delayed-tau model, with the peak at z~2 and an e-folding time of 3.9 Gyr.Comment: 23 pages, 16 figures, 6 tables, accepted for publication in Astronomy
& Astrophysics. *Abridged abstract
Green determination of brominated flame retardants and organochloride pollutants in fish oils by vortex assisted liquid-liquid microextraction and gas chromatography-tandem mass spectrometry
A "green", simple, and low-cost sample extraction procedure involving the use of a deep eutectic solvent (DES) in a vortex assisted liquid-liquid microextraction (VALLME) technique followed by gas chromatography-tandem mass spectrometry (GC-MS/MS) analysis was developed for the simultaneous determination of different PBDEs congeners and OCPs residues in fish oils. After evaluation of different eutectic mixtures, the extraction parameters (volume of DES, amount of oil sample and extraction time) were optimized by means of experimental design in order to maximise extraction efficiency. The developed method was validated in terms of linearity, accuracy and precision, presenting limits of detection in the low ngâŻgâ1 level. Its application in the analysis of five fish oil samples, allowed the detection of all the target analytes at levels up 21.5âŻngâŻgâ1. Fish oils used in animal feed showed to be more contaminated than fish oils for human consumption.Sara C. Cunha and JosĂ© O. Fernandes thanks REQUIMTE, FCT Fundação para a CiĂȘncia e a Tecnologia) and FEDER through the project UID/ QUI/50006/2013 - POCI/01/0145/FEDER/007265 with financial support from FCT/MEC through national funds and co-financed by FEDER, under the Partnership Agreement PT2020. Sara C. Cunha acknowledges FCT for IF/01616/2015 contract. Angela G. Solaesa acknowledges University of Burgos for her pre-doctoral contract and Iberoamerican Santander Research Grant (2017) for the mobility financial support. Thanks to European Regional Development Fund (ERDF) and Junta de Castilla y LeĂłn for financial support of project BU055U16
Physical activity quantification in elder women
CuantificaciĂłn de la actividad fĂsica en mujeres mayores
The spatially resolved star formation history of CALIFA galaxies: Cosmic time scales
This paper presents the mass assembly time scales of nearby galaxies observed
by CALIFA at the 3.5m telescope in Calar Alto. We apply the fossil record
method of the stellar populations to the complete sample of the 3rd CALIFA data
release, with a total of 661 galaxies, covering stellar masses from 10
to 10 M and a wide range of Hubble types. We apply spectral
synthesis techniques to the datacubes and process the results to produce the
mass growth time scales and mass weighted ages, from which we obtain temporal
and spatially resolved information in seven bins of galaxy morphology and six
bins of stellar mass (M) and stellar mass surface density
(). We use three different tracers of the spatially resolved
star formation history (mass assembly curves, ratio of half mass to half light
radii, and mass-weighted age gradients) to test if galaxies grow inside-out,
and its dependence with galaxy stellar mass, , and morphology.
Our main results are as follows: (a) The innermost regions of galaxies assemble
their mass at an earlier time than regions located in the outer parts; this
happens at any given M, , or Hubble type, including
the lowest mass systems. (b) Galaxies present a significant diversity in their
characteristic formation epochs for lower-mass systems. This diversity shows a
strong dependence of the mass assembly time scales on and
Hubble type in the lower-mass range (10 to 10), but a very
mild dependence in higher-mass bins. (c) All galaxies show negative
log age gradients in the inner 1 HLR. The profile
flattens with increasing values of . There is no significant
dependence on M within a particular bin, except for
the lowest bin, where the gradients becomes steeper.Comment: 15 pages, 13 figures, 3 tables, accepted for publication in Astronomy
& Astrophysics. *Abridged abstract
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