Inferences on the Timeline of Reionization at z~8 From the KMOS Lens-Amplified Spectroscopic Survey

Detections and non-detections of Lyman alpha (Ly$\alpha$) emission from $z>6$ galaxies ($<1$ Gyr after the Big Bang) can be used to measure the timeline of cosmic reionization. Of key interest to measuring reionization's mid-stages, but also increasing observational challenge, are observations at z > 7, where Ly$\alpha$ redshifts to near infra-red wavelengths. Here we present a search for z > 7.2 Ly$\alpha$ emission in 53 intrinsically faint Lyman Break Galaxy candidates, gravitationally lensed by massive galaxy clusters, in the KMOS Lens-Amplified Spectroscopic Survey (KLASS). With integration times of ~7-10 hours, we detect no Ly$\alpha$ emission with S/N>5 in our sample. We determine our observations to be 80% complete for 5$\sigma$ spatially and spectrally unresolved emission lines with integrated line flux $>5.7\times10^{-18}$ erg s$^{-1}$ cm$^{-2}$. We define a photometrically selected sub-sample of 29 targets at $z=7.9\pm0.6$, with a median 5$\sigma$ Ly$\alpha$ EW limit of 58A. We perform a Bayesian inference of the average intergalactic medium (IGM) neutral hydrogen fraction using their spectra. Our inference accounts for the wavelength sensitivity and incomplete redshift coverage of our observations, and the photometric redshift probability distribution of each target. These observations, combined with samples from the literature, enable us to place a lower limit on the average IGM neutral hydrogen fraction of $> 0.76 \; (68\%), \; > 0.46 \; (95\%)$ at z ~ 8, providing further evidence of rapid reionization at z~6-8. We show that this is consistent with reionization history models extending the galaxy luminosity function to $M_\textrm{UV} \lesssim -12$, with low ionizing photon escape fractions, $f_\textrm{esc} \lesssim 15\%$.Comment: Accepted for publication in MNRA

Panorama da nutrigenômica no Brasil sob a perspectiva da Bioética

Nutrigenomics has positioned itself, in the scientific and popular context, as an alternative to prevent diseases, which genetically determined predisposition can be avoided or encouraged, depending on the context the individual is at. The study investigated the potential of nutrigenomics in mitigating or generating vulnerabilities. The purpose was to establish the panorama of nutrigenomics in Brazil from the perspective of Bioethics. The study consisted of a quantitative mapping of the nutrigenomics panorama in the scientific and popular context of Brazil, and of an exploratory bibliographic analysis in order to identify moral agents and patients, as well as vulnerabilities to pro- mote reflection in light of Bioethics. The scenario of nutrigenomics in Brazil, built from 18 scientific texts and 600 popular contents, evidenced the prematurity of the area in the scientific context in comparison with a wide incorporation by the popular media. The incorporation of Bioethics in the debate was analyzed in 44 scientific articles, from which the philosophical, biological, cultural, legal and health contexts in which it is found were identified as conditioning aspects of decisions of the moral agent. The vulnerabilities and paradigm changes necessary to implement it in Brazil were related, in order to mitigate the potential for generating vulnerabilities. Bioethics can and should have a broader and more effective action on nutrigenomics questionings by normalizing and guiding the development of this promising area. Thus, it must aim at paradigm shifts in science, professionals, the market, the patient and the consumer so that the potential aspects of generating the identified vulnerabilities are eliminated and contribute to the quality of life of all living beings in the world of this and future generations.La nutrigenómica ha configurado, en el medio científico y popular, como alternativa para prevenir enfermedades, cuya predisposición determinada genéticamente puede evitarse o estimularse, dependiendo del entorno en el que el individuo se encuentra. El estudio indagó el potencial de la nutrigenómica en mitigar o generar vulnerabilidades. El propósito fue establecer el panorama de la nutrigenómica en Brasil desde la perspectiva de la Bioética. El estudio ha consistido en un mapeo cuantitativo del panorama de la nutrigenómica en el contexto científico y popular de Brasil, y en un análisis bibliográfico exploratorio con el fin de identificar los agentes y pacientes morales, así como las vulnerabilidades para promover una reflexión a la luz de la Bioética. El escenario de la nutrigenómica en Brasil, elaborado desde 18 textos científicos y 600 contenidos populares, evidenció la prematuridad del área en el contexto científico en confronto con una amplia incorporación por el medio popular. La incorporación de la Bioética en el debate se analizó en 44 artículos científicos, a partir de los que se identificaron como aspectos condicionantes de decisiones del agente moral los contextos filosófico, biológico, cultural, legal y sanitario en los que se encuentra. Se relacionaron las vulnerabilidades y cambios de paradigmas necesarios para implementarlo en Brasil, con la finalidad de mitigar el potencial de generación de vulnerabilidades. La Bioética puede y debe tener una actuación más amplia y efectiva en los cuestionamientos de la nutrigenómica al normalizar y orientar el desarrollo de esta área prometedora. Así, debe apuntar a los cambios de paradigmas da ciencia, de los profesionales, del mercado, del paciente y del consumidor para que se supriman los aspectos potenciales de generación de las vulnerabilidades identificadas y aportar para la calidad de vida de todos los seres vivos de esta y de futuras generaciones.A nutrigenômica tem configurado, no meio científico e popular, como alternativa para prevenir doenças, cuja predisposição determinada geneticamente pode ser evitada ou estimulada, de- pendendo do ambiente no qual o indivíduo se insere. Este estudo questionou o potencial da nutrigenômica em mitigar ou gerar vulnerabilidades. Objetivou-se traçar o panorama da nutrigenômica no Brasil sob a perspectiva da Bioética. O estudo consistiu em um mapeamento quantitativo do panora- ma da nutrigenômica no cenário científico e popular do Brasil, e em uma análise bibliográfica exploratória com o intuito de identificar os agentes e pacientes morais, bem como as vulnerabilidades com vistas a promover uma reflexão à luz da Bioética. O cenário da nutrigenômica no Brasil, elaborado a partir de 18 textos científicos e de 600 conteúdos populares, indicou a prematuridade da área no contexto científico em confronto com uma ampla incorporação pelo meio popular. A incorporação da Bioética na questão foi analisada em 44 artigos científicos, a partir dos quais foram identificados como aspectos condicionantes de decisões do agente moral os contextos filosófico, biológico, cultural, legal e sanitário nos quais se insere. Foram elencadas as vulnerabilidades e mudanças de paradigmas necessárias para sua implementação no Brasil, a fim de diminuir o potencial de geração de vulnerabilidades. A Bioética pode e deve ter uma atuação mais ampla e efetiva nas questões da nutrigenômica ao normatizar, balizar e orientar o desenvolvimento dessa área promissora. Assim, deve visar às mudanças de paradigmas da ciência, dos profissionais, do mercado, do paciente e do consumidor para serem suprimidos os aspectos potenciais de geração das vulnerabilidades identificadas e contribuir para a qualidade de vida de todos os seres vivos desta e de futuras gerações

Spectrophotometric investigations of Blue Compact Dwarf Galaxies: Markarian 35

We present results from a detailed spectrophotometric analysis of the blue compact dwarf galaxy Mrk 35 (Haro 3), based on deep optical (B,V,R,I) and near-IR (J,H,K) imaging, Halpha narrow-band observations and long-slit spectroscopy. The optical emission of the galaxy is dominated by a central young starburst, with a bar-like shape, while an underlying component of stars, with elliptical isophotes and red colors, extends more than 4 kpc from the galaxy center. High resolution Halpha and color maps allow us to identify the star-forming regions, to spatially discriminate them from the older stars, and to recognize several dust patches. We derive colors and Halpha parameters for all the identified star-forming knots. Observables derived for each knot are corrected for the contribution of the underlying older stellar population, the contribution by emission lines, and from interstellar extinction, and compared with evolutionary synthesis models. We find that the contributions of these three factors are by no means negligible and that they significantly vary across the galaxy. Therefore, careful quantification and subtraction of emission lines, galaxy host contribution, and interstellar reddening at every galaxy position, are essential to derive the properties of the young stars in BCDs. We find that we can reproduce the colors of all the knots with an instantaneous burst of star formation and the Salpeter initial mass function with an upper mass limit of 100 M_solar. In all cases the knots are just a few Myr old. The underlying population of stars has colors consistent with being several Gyr old.Comment: 21 pages, 13 figures. Accepted for publication in ApJ, tentatively scheduled for the ApJ November 1, 2007 v669n1 issu

Kiloparsec-scale gaseous clumps and star formation at z = 5–7

We investigate the morphology of the [Cii] emission in a sample of “normal” star-forming galaxies at 5 < z < 7:2 in relation to their UV (rest-frame) counterpart. We use new ALMA observations of galaxies at z 6 7, as well as a careful re-analysis of archival ALMA data. In total 29 galaxies were analysed, 21 of which are detected in [Cii]. For several of the latter the [Cii] emission breaks into multiple components. Only a fraction of these [Cii] components, if any, is associated with the primary UV systems, while the bulk of the [Cii] emission is associated either with fainter UV components, or not associated with any UV counterpart at the current limits. By taking into account the presence of all these components, we find that the L[CII]-SFR relation at early epochs is fully consistent with the local relation, but it has a dispersion of 0.48 0.07 dex, which is about two times larger than observed locally. We also find that the deviation from the local L[CII]-SFR relation has a weak anti-correlation with the EW(Ly ). The morphological analysis also reveals that [Cii] emission is generally much more extended than the UV emission. As a consequence, these primordial galaxies are characterised by a [Cii] surface brightness generally much lower than expected from the local [CII] SFR relation. These properties are likely a consequence of a combination of di erent e ects, namely: gas metallicity, [Cii] emission from obscured star-forming regions, strong variations of the ionisation parameter, and circumgalactic gas in accretion or ejected by these primeval galaxies.European Research Council RM acknowledges ERC Advanced Grant 695671 ‘QUENCH’. AF acknowledges support from the ERC Advanced Grant INTERSTELLAR H2020/740120

ß-globin gene cluster haplotypes and clinical severity in sickle cell anemia patients in southern Brazil

Hematopoietic stem cell transplantation (HSCT) has emerged as a curative strategy for sickle cell anemia (SCA); it is necessary to find markers of SCA clinical severity to spare those SCA patients whose clinical course is mild from the morbidity and mortality associated with HSCT. Haplotypes have been correlated with the severity of clinical manifestations in SCA patients, and fetal hemoglobin (HbF) and socioeconomic status (SeS) have also been described as negative factors. We studied these factors and their impact on clinical manifestations in a population of Southern Brazilian patients attending the Center for Sickle Cell Anemia at Hospital de Clínicas de Porto Alegre/RS, Brazil. Clinical severity was defined as two or more veno-occlusive episodes per year. The βS haplotypes were determined by PCR in 75 SCA patients. Among the 150 βS chromosomes analyzed, 99 (66%) were identified as Bantu (Ban), 41 (27%) as Benin (Ben), and 10 (7%) as other haplotypes. Most patients in our sample (62.7%) belonged to lower SeS groups, precluding meaningful statistical analysis of SeS impact on clinical severity. There was no correlation between haplotypes or HbF level and SCA clinical severity. Gene polymorphisms and environmental issues have to be taken into consideration

HST Imaging of the Ionizing Radiation from a Star-forming Galaxy at z = 3.794

We report on the HST detection of the Lyman-continuum (LyC) radiation emitted by a galaxy at redshift z=3.794, dubbed Ion1 (Vanzella et al. 2012). The LyC from Ion1 is detected at rest-frame wavelength 820$\sim$890 \AA with HST WFC3/UVIS in the F410M band ($m_{410}=27.60\pm0.36$ magnitude (AB), peak SNR = 4.17 in a circular aperture with radius r = 0.12'') and at 700$\sim$830 \AA with the VLT/VIMOS in the U-band ($m_U = 27.84\pm0.19$ magnitude (AB), peak SNR = 6.7 with a r = 0.6'' aperture). A 20-hr VLT/VIMOS spectrum shows low- and high-ionization interstellar metal absorption lines, the P-Cygni profile of CIV and Ly$\alpha$ in absorption. The latter spectral feature differs from what observed in known LyC emitters, which show strong Ly$\alpha$ emission. An HST far-UV color map reveals that the LyC emission escapes from a region of the galaxy that is bluer than the rest, presumably because of lower dust obscuration. The F410M image shows that the centroid of the LyC emission is offset from the centroid of the non-ionizing UV emission by 0.12''$\pm$0.03'', corresponding to 0.85$\pm$0.21 kpc (physical), and that its morphology is likely moderately resolved. These morphological characteristics favor a scenario where the LyC photons produced by massive stars escape from low HI column-density "cavities" in the ISM, possibly carved by stellar winds and/or supernova. We also collect the VIMOS U-band images of a sample of 107 Lyman-break galaxies with spectroscopic redshifts at $3.40<z<3.95$, i.e. sampling the LyC, and stack them with inverse-variance weights. No LyC emission is detected in the stacked image, resulting in a 32.5 magnitude (AB) flux limit (1$\sigma$) and an upper limit of absolute LyC escape fraction $f_{esc}^{abs} < 0.63\%$. LyC emitters like Ion1 are very likely at the bright-end of the LyC luminosity function.Comment: 24 pages, 13 figures, accepted for publication in Ap

The stellar metallicities of massive quiescent galaxies at 1.0 &lt; z &lt; 1.3 from KMOS+VANDELS

We present a rest-frame UV-optical stacked spectrum representative of massive quiescent galaxies at $1.010.8$. The stack is constructed using VANDELS survey data, combined with new KMOS observations. We apply two independent full-spectral-fitting approaches, measuring a total metallicity, [Z/H]=$-0.13\pm0.08$ with Bagpipes, and [Z/H]=$0.04\pm0.14$ with Alf, a fall of $\sim0.2-0.3$ dex compared with the local Universe. We also measure an iron abundance, [Fe/H] =$-0.18\pm0.08$, a fall of $\sim0.15$ dex compared with the the local Universe. We measure the alpha enhancement via the magnesium abundance, obtaining [Mg/Fe]=$0.23\pm$0.12, consistent with similar-mass galaxies in the local Universe, indicating no evolution in the average alpha enhancement of log$(M_*/\rm{M_\odot})=11$ quiescent galaxies over the last $\sim8$ Gyr. This suggests the very high alpha enhancements recently reported for several bright $z\sim1-2$ quiescent galaxies are due to their extreme masses, log$(M_*/\rm{M_\odot})\gtrsim11.5$, rather than being typical of the $z\gtrsim1$ population. The metallicity evolution we observe with redshift (falling [Z/H], [Fe/H], constant [Mg/Fe]) is consistent with recent studies. We recover a mean stellar age of $2.5^{+0.6}_{-0.4}$ Gyr, corresponding to a formation redshift, z_\rm{form}=2.4^{+0.6}_{-0.3}. Recent studies have obtained varying average formation redshifts for $z\gtrsim1$ massive quiescent galaxies, and, as these studies report consistent metallicities, we identify different star-formation-history models as the most likely cause. Larger spectroscopic samples from upcoming ground-based instruments will provide precise constraints on ages and metallicities at $z\gtrsim1$. Combining these with precise JWST $z>2$ quiescent-galaxy stellar-mass functions will provide an independent test of formation redshifts derived from spectral fitting.Comment: 16 pages, 3 figures, accepted for publication in Ap

Using [Ne V]/[Ne III] to Understand the Nature of Extreme-Ionization Galaxies

Spectroscopic studies of extreme-ionization galaxies (EIGs) are critical to our understanding of exotic systems throughout cosmic time. These EIGs exhibit spectral features requiring >54.42 eV photons: the energy needed to fully ionize helium into He2+ and emit He II recombination lines. They are likely key contributors to reionization, and they can also probe exotic stellar populations or accretion onto massive black holes. To facilitate the use of EIGs as probes of high ionization, we focus on ratios constructed from strong rest-frame UV/optical emission lines, specifically [O III] 5008, H-beta, [Ne III] 3870, [O II] 3727,3729, and [Ne V] 3427. These lines probe the relative intensity at energies of 35.12, 13.62, 40.96, 13.62 eV, and 97.12, respectively, covering a wider range of ionization than traced by other common rest-frame UV/optical techniques. We use ratios of these lines ([Ne V]/[Ne III] = Ne53 and [Ne III]/[O II]), which are closely separated in wavelength, and mitigates effects of dust attenuation and uncertainties in flux calibration. We make predictions from photoionization models constructed from Cloudy that use a broad range of stellar populations and black hole accretion models to explore the sensitivity of these line ratios to changes in the ionizing spectrum. We compare our models to observations from the Hubble Space Telescope and James Webb Space Telescope of galaxies with strong high-ionization emission lines at z ~ 0, z ~ 2, and z ~ 7. We show that the Ne53 ratio can separate galaxies with ionization from 'normal' stellar populations from those with AGN and even 'exotic' Population III models. We introduce new selection methods to identify galaxies with photoionization driven by Population III stars or intermediate-mass black hole accretion disks that could be identified in upcoming high-redshift spectroscopic surveys.Comment: 16 pages, 5 figures, 1 table. Accepted in Ap