Evidence of very low metallicity and high ionization state in a strongly lensed, star-forming dwarf galaxy at z=3.417

We investigate the gas-phase metallicity and Lyman Continuum (LyC) escape fraction of a strongly gravitationally lensed, extreme emission-line galaxy at z=3.417, J1000+0221S, recently discovered by the CANDELS team. We derive ionization and metallicity sensitive emission-line ratios from H+K band LBT/LUCI medium resolution spectroscopy. J1000+0221S shows high ionization conditions, as evidenced by its enhanced [OIII]/[OII] and [OIII]/Hbeta ratios. Consistently, strong-line methods based on the available line ratios suggest that J1000+0221S is an extremely metal-poor galaxy, with a metallicity of 12+log(O/H) < 7.44 (< 5% solar), placing it among the most metal-poor star-forming galaxies at z > 3 discovered so far. In combination with its low stellar mass (2x10^8 Msun) and high star formation rate (5 Msun/yr), the metallicity of J1000+0221S is consistent with the extrapolation to low masses of the mass-metallicity relation traced by Lyman-break galaxies at z > 3, but it is 0.55 dex lower than predicted by the fundamental metallicity relation at z < 2.5. These observations suggest the picture of a rapidly growing galaxy, possibly fed by the massive accretion of pristine gas. Additionally, deep LBT/LBC in the UGR bands are used to derive a limit to the LyC escape fraction, thus allowing us to explore for the first time the regime of sub-L* galaxies at z > 3. We find a 1sigma upper limit to the escape fraction of 23%, which adds a new observational constraint to recent theoretical models predicting that sub-L* galaxies at high-z have high escape fractions and thus are the responsible for the reioization of the Universe.Comment: 5 pages, 3 figures and 1 table. Accepted for publication in ApJ Letter

The [OIII]λ5007 equivalent width distribution at z ∼2: The redshift evolution of the extreme emission line galaxies

We determine the [OIII]$\lambda5007$ equivalent width (EW) distribution of $1.700<\rm{z}<2.274$ rest-frame UV-selected (M$_{\rm{UV}}<-19$) star-forming galaxies in the GOODS North and South fields. We make use of deep HDUV broadband photometry catalogues for selection and 3D-HST WFC3/IR grism spectra for measurement of line properties. The [OIII]$\lambda5007$ EW distribution allows us to measure the abundance of extreme emission line galaxies (EELGs) within this population. We model a log-normal distribution to the [OIII]$\lambda5007$ rest-frame equivalent widths of galaxies in our sample, with location parameter $\mu=4.24\pm0.07$ and variance parameter $\sigma= 1.33\pm0.06$. This EW distribution has a mean [OIII]$\lambda5007$ EW of 168$\pm1\r{A}$. The fractions of $\rm{z}\sim2$ rest-UV-selected galaxies with [OIII]$\lambda5007$ EWs greater than $500, 750$ and $1000\r{A}$ are measured to be $6.8^{+1.0}_{-0.9}\%$, $3.6^{+0.7}_{-0.6}\%$, and $2.2^{+0.5}_{-0.4}\%$ respectively. The EELG fractions do not vary strongly with UV luminosity in the range ($-21.6<M_{\rm{UV}}<-19.0$) considered in this paper, consistent with findings at higher redshifts. We compare our results to $\rm{z}\sim5$ and $\rm{z}\sim7$ studies where candidate EELGs have been discovered through Spitzer/IRAC colours, and we identify rapid evolution with redshift in the fraction of star-forming galaxies observed in an extreme emission line phase (a rise by a factor $\sim10$ between $\rm{z}\sim2$ and $\rm{z}\sim7$). This evolution is consistent with an increased incidence of strong bursts in the galaxy population of the reionisation era. While this population makes a sub-dominant contribution of the ionising emissivity at $\rm{z}\simeq2$, EELGs are likely to dominate the ionising output in the reionisation era

The MUSE-Wide Survey: A first catalogue of 831 emission line galaxies

We present a first instalment of the MUSE-Wide survey, covering an area of 22.2 arcmin$^2$ (corresponding to $\sim$20% of the final survey) in the CANDELS/Deep area of the Chandra Deep Field South. We use the MUSE integral field spectrograph at the ESO VLT to conduct a full-area spectroscopic mapping at a depth of 1h exposure time per 1 arcmin$^2$ pointing. We searched for compact emission line objects using our newly developed LSDCat software based on a 3-D matched filtering approach, followed by interactive classification and redshift measurement of the sources. Our catalogue contains 831 distinct emission line galaxies with redshifts ranging from 0.04 to 6. Roughly one third (237) of the emission line sources are Lyman $\alpha$ emitting galaxies with $3 < z < 6$, only four of which had previously measured spectroscopic redshifts. At lower redshifts 351 galaxies are detected primarily by their [OII] emission line ($0.3 \lesssim z \lesssim 1.5$), 189 by their [OIII] line ($0.21 \lesssim z \lesssim 0.85$), and 46 by their H$\alpha$ line ($0.04 \lesssim z \lesssim 0.42$). Comparing our spectroscopic redshifts to photometric redshift estimates from the literature, we find excellent agreement for $z<1.5$ with a median $\Delta z$ of only $\sim 4 \times 10^{-4}$ and an outlier rate of 6%, however a significant systematic offset of $\Delta z = 0.26$ and an outlier rate of 23% for Ly$\alpha$ emitters at $z>3$. Together with the catalogue we also release 1D PSF-weighted extracted spectra and small 3D datacubes centred on each of the 831 sources.Comment: 24 pages, 14 figures, accepted for publication in A&A, data products are available for download from http://muse-vlt.eu/science/muse-wide-survey/ and later via the CD

UM 462, a local Green Pea galaxy analog under the MUSE magnifying glass

[ABRIGED] Stellar feedback in high-redshift galaxies plays an important role in the re-ionization epoch of the Universe. Green Pea galaxies (GPs) postulate as favorite local laboratories. However, at their typical redshift of $z\sim0.2$, the most intimate interaction between stars and surrounding ISM cannot be disentangled. Detailed studies of Blue Compact Dwarf galaxies (BCDs) are necessary to anchor our investigations on them. We present here a study in detail UM 462, a BCD with similar properties to GPs uisng high quality optical IFS data with MUSE. Total oxygen abundance by means of the direct method is 12+$\log$(O/H)$\sim$8.02 and homogenous all over the galaxy, in stark contrast with the metallicities derived from several strong line methods. The velocity field for the ionised gas presents a velocity stratification in the area towards the north with redder velocities in the high ionisation lines and bluer velocities in the low ionisation lines. This is the only area with velocity dispersions clearly above the MUSE instrumental width, and it is surrounded by two $\sim$1 kpc-long structures nicknamed \emph{the horns}. We interpret the observational evidence in that area as a fragmented super-bubble fruit of the stellar feedback and it may constitute a preferred channel for LyC photons from the youngest generation of stars to escape. The most recent SF seems to propagate from the outer to the inner parts of the galaxy, and then from east to west. We identified a supernova remnant and Wolf-Rayet stars - as traced by the red bump - that support this picture. The direction of the propagation implies the presence of younger Wolf-Rayet stars at the maximum in H$\alpha$. The ensemble of results exemplifies the potential of 2D detailed spectroscopic studies of dwarf star-forming galaxies at high spatial resolution as key reference for similar studies on primeval galaxies.Comment: 29 pages, 25 figures; resubmitted to A&A after taking the referee's comments and suggestions into accoun

The MUSE-Wide Survey: Survey Description and First Data Release

We present the MUSE-Wide survey, a blind, 3D spectroscopic survey in the CANDELS/GOODS-S and CANDELS/COSMOS regions. Each MUSE-Wide pointing has a depth of 1 hour and hence targets more extreme and more luminous objects over 10 times the area of the MUSE-Deep fields (Bacon et al. 2017). The legacy value of MUSE-Wide lies in providing "spectroscopy of everything" without photometric pre-selection. We describe the data reduction, post-processing and PSF characterization of the first 44 CANDELS/GOODS-S MUSE-Wide pointings released with this publication. Using a 3D matched filtering approach we detected 1,602 emission line sources, including 479 Lyman-$\alpha$ (Lya) emitting galaxies with redshifts $2.9 \lesssim z \lesssim 6.3$. We cross-match the emission line sources to existing photometric catalogs, finding almost complete agreement in redshifts and stellar masses for our low redshift (z < 1.5) emitters. At high redshift, we only find ~55% matches to photometric catalogs. We encounter a higher outlier rate and a systematic offset of $\Delta$z$\simeq$0.2 when comparing our MUSE redshifts with photometric redshifts. Cross-matching the emission line sources with X-ray catalogs from the Chandra Deep Field South, we find 127 matches, including 10 objects with no prior spectroscopic identification. Stacking X-ray images centered on our Lya emitters yielded no signal; the Lya population is not dominated by even low luminosity AGN. A total of 9,205 photometrically selected objects from the CANDELS survey lie in the MUSE-Wide footprint, which we provide optimally extracted 1D spectra of. We are able to determine the spectroscopic redshift of 98% of 772 photometrically selected galaxies brighter than 24th F775W magnitude. All the data in the first data release - datacubes, catalogs, extracted spectra, maps - are available on the website https://musewide.aip.de. [abridged]Comment: 25 pages 15+1 figures. Accepted, A&A. Comments welcom

Discovery of a Quadruple Lens in CANDELS with a Record Lens Redshift z=1.53

Using spectroscopy from the Large Binocular Telescope and imaging from the Hubble Space Telescope we discovered the first strong galaxy lens at z(lens)>1. The lens has a secure photometric redshift of z=1.53+/-0.09 and the source is spectroscopically confirmed at z=3.417. The Einstein radius (0.35"; 3.0 kpc) encloses 7.6 x 10^10 Msol, with an upper limit on the dark matter fraction of 60%. The highly magnified (40x) source galaxy has a very small stellar mass (~10^8 Msol) and shows an extremely strong [OIII]_5007A emission line (EW_0 ~ 1000A) bolstering the evidence that intense starbursts among very low-mass galaxies are common at high redshift.Comment: accepted for publication in ApJ Letter

Reliability of 4-m and 6-m walking speed tests in elderly people with cognitive impairment

[Abstract] The purpose of this study was to evaluate the interrater and test–retest reliability of 4-m and 6-m walking speed tests in elderly people with cognitive impairment. 50 subjects aged 65 and over with cognitive impairment were selected from an adult day-care centre and a nursing home. To examine interrater reliability, 21 people were evaluated independently by two researchers who administered the 4-m and 6-m walking tests in each evaluation. For test–retest reliability, two observers administered the tests to the same 29 subjects, with a time interval of one week. Intraclass correlation coefficients (ICCs) were calculated to examine interrater and test–retest reliability. The ICCs for interrater reliability reached values of 0.96 and 0.88 for the 4-m and 6-m walking tests, respectively. In the test–retest study, the time interval was 7.4 1.17 days. The ICCs were 0.91 for the 4-m test and 0.86 for the 6-m test. The results support the use of walking tests in elderly people with cognitive impairment

Nickel-Catalyzed Cycloisomerization of 1,5-Allenynes

We report the Ni-catalyzed cycloisomerization of 1,5-allenynes. Substrates containing terminal alkynes afford cyclopentene derivatives, whereas internal alkynes lead to the formation of two consecutive C C bonds to give fused 5–5 bicyclic compounds. The reaction shows a wide scope. Experimental and computational mechanistic studies suggest a Ni(0) Ni(II) catalytic cycle. The reaction starts with an oxidative cyclometallation followed by a β-hydrogen elimination. The trans arrangement of alkenyl and hydride ligands is key to allow formation of the second carbocycMICIU (CTQ2016-79826-R and PID2019-109088GB-100

Pain as a mediator in the temperament-alexithymia relationship in individuals suffering from rheumatoid arthritis

[Abstract] OBJECTIVE: The study aims to establish a relationship between temperament traits, symptoms of alexithymia, and pain intensity in rheumatoid arthritis. Despite the significant progress seen in the area of RA treatment, pain, often life-long, remains the predominant symptom. This constant pain and progressing disability, as well as dependence upon other people cause RA patients to experience psychological stress that can be modified by individual patient traits. Recently, several authors have underlined the need to relate personality and temperament constructs to neurobiological processes that may underlie individual differences. It seems then that patient characteristics may play a significant role in the course of the disease. PATIENTS AND METHODS: The study was performed on a group of patients (N=317) with rheumatoid arthritis diagnosed according to the current criteria of the American-European Consensus of 2010. All patients expressed voluntary consent to participate, and the study protocol was approved by the Local Ethics Committee. This was a survey-based study. It involved the application of the adult version of the Buss and Plomin EAS Temperament Questionnaire (EAS-D), which tests 3 main temperament domains: sociability, activity, and emotionality. The pain was measured on the Visual Analogue Scale (VAS). VAS is used to measure pain intensity. The level of alexithymia was tested using the Toronto Alexithymia Scale-20. The scale consists of 20 statements and includes 3 subscales that measure difficulty in describing feelings/emotions, difficulty in identifying feelings/emotions, and operational externally oriented thinking. RESULTS: The analysis revealed that alexithymia is positively correlated only with one dimension of temperament, i.e., emotionality, and with pain intensity. Moreover, high emotionality was positively correlated with pain. A simple mediation analysis revealed that pain intensity functioned as a mediator in the emotionality-alexithymia relationship. CONCLUSIONS: The observed correlations indicate that RA patients with a high level of emotionality exhibit high alexithymia as they perceive pain related to the disease symptoms more intensely. The observed mediation is partial, meaning that there are also other mediating factors in this relationship