Uncertainties in gas kinematics arising from stellar continuum modelling in integral field spectroscopy data: the case of NGC2906 observed with MUSE/VLT

We study how the use of several stellar subtraction methods and line fitting approaches can affect the derivation of the main kinematic parameters (velocity and velocity dispersion fields) of the ionized gas component. The target of this work is the nearby galaxy NGC 2906, observed with the MUSE instrument at Very Large Telescope. A sample of twelve spectra is selected from the inner (nucleus) and outer (spiral arms) regions, characterized by different ionization mechanisms. We compare three different methods to subtract the stellar continuum (FIT3D, STARLIGHT and pPXF), combined with one of the following stellar libraries: MILES, STELIB and GRANADA+MILES. The choice of the stellar subtraction method is the most important ingredient affecting the derivation of the gas kinematics, followed by the choice of the stellar library and by the line fitting approach. In our data, typical uncertainties in the observed wavelength and width of the H\alpha and [NII] lines are of the order of _rms \sim 0.1\AA\ and _rms \sim 0.2\AA\ (\sim 5 and 10km/s, respectively). The results obtained from the [NII] line seem to be slightly more robust, as it is less affected by stellar absorption than H\alpha. All methods considered yield statistically consistent measurements once a mean systemic contribution \Delta\bar\lambda=\Delta\bar\sigma=0.2xDelta_{MUSE} is added in quadrature to the line fitting errors, where \Delta_{MUSE} = 1.1\AA\ \sim 50 km/s denotes the instrumental resolution of the MUSE spectra. Although the subtraction of the stellar continuum is critical in order to recover line fluxes, any method (including none) can be used in order to measure the gas kinematics, as long as an additional component of 0.2 x Delta_MUSE is added to the error budget.Comment: 20 pages, 14 figure

PPAK Wide-field Integral Field Spectroscopy of NGC 628: I. The largest spectroscopic mosaic on a single galaxy

We present a wide-field IFS survey on the nearby face-on Sbc galaxy NGC 628, comprising 11094 individual spectra, covering a nearly circular field-of-view of ~6 arcmin in diameter, with a sampling of ~2.7 arcsec per spectrum in the optical wavelength range (3700--7000 AA). This galaxy is part of the PPAK IFS Nearby Galaxies Survey, (PINGS, Rosales-Ortega et al. 2009). To our knowledge, this is the widest spectroscopic survey ever made in a single nearby galaxy. A detailed flux calibration was applied, granting a spectrophotometric accuracy of $\sim$\,0.2 mag. The age of the stellar populations shows a negative gradient from the inner (older) to the outer (younger) regions. We found an inversion of this gradient in the central ~1 kpc region, where a somewhat younger stellar population is present within a ring at this radius. This structure is associated with a circumnuclear star-forming region at ~ 500 pc, also found in similar spiral galaxies. From the study of the integrated and spatially resolved ionized gas we found a moderate SFR of ~ 2.4 Msun yr$^{-1}$. The oxygen abundance shows a a clear gradient of higher metallicity values from the inner part to the outer part of the galaxy, with a mean value of 12~+~log(O/H) ~ 8.7. At some specific regions of the galaxy, the spatially resolved distribution of the physical properties show some level of structure, suggesting real point-to-point variations within an individual \hh region. Our results are consistent with an inside-out growth scheme, with stronger star formation at the outer regions, and with evolved stellar populations in the inner ones.Comment: 31 pages, 22 Figuras, Accepted for Publishing in MNRAS (corrected PDF

High spatial resolution and high contrast optical speckle imaging with FASTCAM at the ORM

In this paper, we present an original observational approach, which combines, for the first time, traditional speckle imaging with image post-processing to obtain in the optical domain diffraction-limited images with high contrast (1e-5) within 0.5 to 2 arcseconds around a bright star. The post-processing step is based on wavelet filtering an has analogy with edge enhancement and high-pass filtering. Our I-band on-sky results with the 2.5-m Nordic Telescope (NOT) and the lucky imaging instrument FASTCAM show that we are able to detect L-type brown dwarf companions around a solar-type star with a contrast DI~12 at 2" and with no use of any coronographic capability, which greatly simplifies the instrumental and hardware approach. This object has been detected from the ground in J and H bands so far only with AO-assisted 8-10 m class telescopes (Gemini, Keck), although more recently detected with small-class telescopes in the K band. Discussing the advantage and disadvantage of the optical regime for the detection of faint intrinsic fluxes close to bright stars, we develop some perspectives for other fields, including the study of dense cores in globular clusters. To the best of our knowledge this is the first time that high contrast considerations are included in optical speckle imaging approach.Comment: Proceedings of SPIE conference - Ground-based and Airborne Instrumentation for Astronomy III (Conference 7735), San Diego 201

Discovery of a wide companion near the deuterium burning mass limit in the Upper Scorpius association

We present the discovery of a companion near the deuterium burning mass limit located at a very wide distance, at an angular separation of 4.6+/-0.1 arcsec (projected distance of ~ 670 AU) from UScoCTIO108, a brown dwarf of the very young Upper Scorpius association. Optical and near-infrared photometry and spectroscopy confirm the cool nature of both objects, with spectral types of M7 and M9.5, respectively, and that they are bona fide members of the association, showing low gravity and features of youth. Their masses, estimated from the comparison of their bolometric luminosities and theoretical models for the age range of the association, are 60+/-20 and 14^{+2}_{-8} MJup, respectively. The existence of this object around a brown dwarf at this wide orbit suggests that the companion is unlikely to have formed in a disk based on current planet formation models. Because this system is rather weakly bound, they did not probably form through dynamical ejection of stellar embryos.Comment: 10 pages, including 4 figures and 2 table

On Brane Inflation Potentials and Black Hole Attractors

We propose a new potential in brane inflation theory, which is given by the arctangent of the square of the scalar field. Then we perform an explicit computation for inflationary quantities. This potential has many nice features. In the small field approximation, it reproduces the chaotic and MSSM potentials. It allows one, in the large field approximation, to implement the attractor mechanism for bulk black holes where the geometry on the brane is de Sitter. In particular, we show, up to some assumptions, that the Friedman equation can be reinterpreted as a Schwarzschild black hole attractor equation for its mass parameter.Comment: 12 pages. Reference updated and minor changes added. Version to appear in Int. J. Mod. Phys.

Development of atopy and asthma: candidate environmental influences and important periods of exposure.

Atopy is a major risk factor for the development of asthma. Immune processes that lead to the development of antigen-specific IgE are essential to the development of atopy. This review examines the immune processes that are candidate targets for modulation by environmental agents; environmental and lifestyle factors that have been suggested as modulators of the development of atopy; and the impact of known environmental agents on atopic processes in the airway. The most important periods of immune development with regard to expression of atopy are likely during gestation and early childhood. A better understanding of which environmental agents are important, as well as the period of life during which these agents may exert an important effect, is essential to devising rational environmental avoidance strategies for at-risk populations

Directional and Polarized Lasing Action on Pb-free FASnI3 Integrated in Flexible Optical Waveguide

In this work, high-quality FASnI3 (FA, formamidinium) lead-free perovskite thin films are successfully incorporated in a flexible polyethylene terephthalate (PET) substrate to demonstrate amplified spontaneous emission (ASE) and lasing. The waveguide (WG) consists of polymethylmethacrylate(PMMA)/FASnI3 bilayer deposited on a PET substrate and is properly designed to allow single-mode propagation at the photoluminescence wavelength. This geometry optimizes the excitation of the emitting FASnI3, enhances the light−matter interaction in the semiconductor thin film, provides a preferable direction for the emitted light and allows its direct outcoupling for on-chip or fiber-optic applications. As far as the authors know, ASE and random lasing are obtained for the first time in a flexible-based WG integrating a highly efficient lead-free perovskite. The high quality of the deposited films and the optimized design of the structure result in an extremely low ASE/lasing threshold in the range of 1 µJ cm−2, which is only ten times higher than that measured in the same PMMA/FASnI3 structure deposited on a rigid substrate (Si/SiO2). More interestingly, these WGs exhibit a strong polarization anisotropy for the outcoupled ASE/lasing light with a preferable transverse electric polarization. This work is the base for the future development of ecofriendly, flexible, and efficient photonic devices.This project received funding from the European Union's Horizon 2020 research and innovation programme under grant agreement No 862656 (project DROP-IT) and the European Research Council (ERC) via Consolidator Grant (724424, No-LIMIT) and by the Spanish MINECO through projects no. PID2020-120484RB-I00 and PID2019-107314RB-I00 (Stable)

Síndrome de fatiga crónica en una adolescente de 15 años

Fatigue and lack of energy are frequent symptoms in children and adolescents. A diagnosis of chronic fatigue syndrome should be considered in children and adolescents who complain of chronic fatigue associated with other symptoms without a demonstrable physical cause. Lack of knowledge about this syndrome and late diagnosis may have a negative impact on the normal development of affected children and adolescents. Treatment should be based on a rehabilitation program with cognitive behavioral therapy and a gradual increase in activities