| 1. |
- Gaulton, Kyle J, et al.
(författare)
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Genetic fine mapping and genomic annotation defines causal mechanisms at type 2 diabetes susceptibility loci.
- 2015
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Ingår i: Nature Genetics. - : Springer Science and Business Media LLC. - 1546-1718 .- 1061-4036. ; 47:12, s. 1415-1415
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Tidskriftsartikel (refereegranskat)abstract
- We performed fine mapping of 39 established type 2 diabetes (T2D) loci in 27,206 cases and 57,574 controls of European ancestry. We identified 49 distinct association signals at these loci, including five mapping in or near KCNQ1. 'Credible sets' of the variants most likely to drive each distinct signal mapped predominantly to noncoding sequence, implying that association with T2D is mediated through gene regulation. Credible set variants were enriched for overlap with FOXA2 chromatin immunoprecipitation binding sites in human islet and liver cells, including at MTNR1B, where fine mapping implicated rs10830963 as driving T2D association. We confirmed that the T2D risk allele for this SNP increases FOXA2-bound enhancer activity in islet- and liver-derived cells. We observed allele-specific differences in NEUROD1 binding in islet-derived cells, consistent with evidence that the T2D risk allele increases islet MTNR1B expression. Our study demonstrates how integration of genetic and genomic information can define molecular mechanisms through which variants underlying association signals exert their effects on disease.
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| 2. |
- Ferreras, Ignacio, et al.
(författare)
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FIGS : spectral fitting constraints on the star formation history of massive galaxies since the cosmic noon
- 2019
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Ingår i: Monthly notices of the Royal Astronomical Society. - : Oxford University Press (OUP). - 0035-8711 .- 1365-2966. ; 486:1, s. 1358-1376
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Tidskriftsartikel (refereegranskat)abstract
- We constrain the stellar population properties of a sample of 52 massive galaxies - with stellar mass log (M-s/M-circle dot) greater than or similar to 10.5 - over the redshift range 0.5 < z < 2 by use of observer-frame optical and near-infrared slitless spectra from Hubble Space Telescope's ACS and WFC3 grisms. The deep exposures (similar to 100 ks) allow us to target individual spectra of massive galaxies to F160W = 22.5AB. Our spectral fitting approach uses a set of six base models adapted to the redshift and spectral resolution of each observation, and fits the weights of the base models, including potential dust attenuation, via a Markov Chain Monte Carlo method. Our sample comprises a mixed distribution of quiescent (19) and star-forming galaxies (33). We quantify the width of the age distribution (Delta t) that is found to dominate the variance of the retrieved parameters according to principal component analysis. The population parameters follow the expected trend towards older ages with increasing mass, and Delta t appears to weakly anticorrelate with stellar mass, suggesting a more efficient star formation at the massive end. As expected, the redshift dependence of the relative stellar age (measured in units of the age of the Universe at the source) in the quiescent sample rejects the hypothesis of a single burst (aka monolithic collapse). Radial colour gradients within each galaxy are also explored, finding a wider scatter in the star-forming subsample, but no conclusive trend with respect to the population parameters.
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| 3. |
- Gazzi, Arianna, et al.
(författare)
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Graphene, other carbon nanomaterials and the immune system: toward nanoimmunity-by-design
- 2020
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Ingår i: JPhys Materials. - : IOP Publishing. - 2515-7639. ; 3:3
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Tidskriftsartikel (refereegranskat)abstract
- Carbon-based materials (CBMs), such as graphene, nanodiamonds, carbon fibers, and carbon dots, have attracted a great deal scientific attention due to their potential as biomedical tools. Following exposure, particularly intravenous injection, these nanomaterials can be recognized by immune cells. Such interactions could be modulated by the different physicochemical properties of the materials (e.g. structure, size, and chemical functions), by either stimulating or suppressing the immune response. However, a harmonized cutting-edge approach for the classification of these materials based not only on their physicochemical parameters but also their immune properties has been missing. The European Commission-funded G-IMMUNOMICS and CARBO-IMmap projects aimed to fill this gap, developing a functional pipeline for the qualitative and quantitative immune characterization of graphene, graphene-related materials (GRMs), and other CBMs. The goal was to open breakthrough perspectives for the definition of the immune profiles of these materials. Here, we summarize our methodological approach, key results, and the necessary multidisciplinary expertise ranging across various fields, from material chemistry to engineering, immunology, toxicology, and systems biology. G-IMMUNOMICS, as a partnering project of the Graphene Flagship, the largest scientific research initiative on graphene worldwide, also complemented the studies performed in the Flagship on health and environmental impact of GRMs. Finally, we present the nanoimmunity-by-design concept, developed within the projects, which can be readily applied to other 2D materials. Overall, the G-IMMUNOMICS and CARBO-IMmap projects have provided new insights on the immune impact of GRMs and CBMs, thus laying the foundation for their safe use and future translation in medicine.
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| 4. |
- Larson, Rebecca L., et al.
(författare)
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Discovery of a z=7.452 High Equivalent Width Ly alpha Emitter from the Hubble Space Telescope Faint Infrared Grism Survey
- 2018
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Ingår i: Astrophysical Journal. - : American Astronomical Society. - 0004-637X .- 1538-4357. ; 858:2
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Tidskriftsartikel (refereegranskat)abstract
- We present the results of an unbiased search for Ly alpha emission from continuum-selected 5.6 < z < 8.7 galaxies. Our data set consists of 160 orbits of G102 slitless grism spectroscopy obtained with the Hubble Space Telescope (HST)/WFC3 as part of the Faint Infrared Grism Survey (FIGS; PI: Malhotra), which obtains deep slitless spectra of all sources in four fields, and was designed to minimize contamination in observations of previously identified high-redshift galaxy candidates. The FIGS data can potentially spectroscopically confirm the redshifts of galaxies, and as Ly alpha emission is resonantly scattered by neutral gas, FIGS can also constrain the ionization state of the intergalactic medium during the epoch of reionization. These data have sufficient depth to detect Ly alpha emission in this epoch, as Tilvi et al. have published the FIGS detection of previously known Ly alpha emission at z = 7.51. The FIGS data use five separate roll angles of HST to mitigate the contamination by nearby galaxies. We created a method that accounts for and removes the contamination from surrounding galaxies and also removes any dispersed continuum light from each individual spectrum. We searched for significant (>4 sigma) emission lines using two different automated detection methods, free of any visual inspection biases. Applying these methods on photometrically selected high-redshift candidates between 5.6 < z < 8.7, we find two emission lines, one previously published by Tilvi et al., (2016) and a new line at 1.028 mu m, which we identify as Ly alpha at z = 7.452 +/- 0.003. This newly spectroscopically confirmed galaxy has the highest Ly alpha rest-frame equivalent width (EWLy alpha) yet published at z > 7 (140.3 +/- 19.0 ångström).
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| 5. |
- Pharo, John, et al.
(författare)
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Emission-line Metallicities from the Faint Infrared Grism Survey and VLT/MUSE
- 2019
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Ingår i: Astrophysical Journal. - : American Astronomical Society. - 0004-637X .- 1538-4357. ; 874:2
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Tidskriftsartikel (refereegranskat)abstract
- We derive direct-measurement gas-phase metallicities of 7.4 < 12 + log (O/H) < 8.4 for 14 low-mass emissionline galaxies at 0.3 < z < 0.8 identified in the Faint Infrared Grism Survey. We use deep slitless G102 grism spectroscopy of the Hubble Ultra Deep Field, dispersing light from all objects in the field at wavelengths between 0.85 and 1.15 mu m. We run an automatic search routine on these spectra to robustly identify 71 emission-line sources, using archival data from Very Large Telescope (VLT)/Multi-Unit Spectroscopic Explorer (MUSE) to measure additional lines and confirm redshifts. We identify 14 objects with 0.3 < z < 0.8 with measurable [O Iota Iota Iota] lambda 4363 angstrom emission lines in matching VLT/MUSE spectra. For these galaxies, we derive direct electron-temperature gas-phase metallicities with a range of 7.4 < 12 + log (O/H) < 8.4. With matching stellar masses in the range of 10(7.9) M-circle dot < M* < 10(10.4) M-circle dot, we construct a mass-metallicity (MZ) relation and find that the relation is offset to lower metallicities compared to metallicities derived from alternative methods (e.g., R-23,O3N2, N2O2) and continuum selected samples. Using star formation rates derived from the H alpha emission line, we calculate our galaxies' position on the Fundamental Metallicity Relation, where we also find an offset toward lower metallicities. This demonstrates that this emission-line-selected sample probes objects of low stellar masses but even lower metallicities than many comparable surveys. We detect a trend suggesting galaxies with higher Specific Star Formation (SSFR) are more likely to have lower metallicity. This could be due to cold accretion of metal-poor gas that drives star formation, or could be because outflows of metal-rich stellar winds and SNe ejecta are more common in galaxies with higher SSFR.
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| 6. |
- Pirzkal, Norbert, et al.
(författare)
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A Two-dimensional Spectroscopic Study of Emission-line Galaxies in the Faint Infrared Grism Survey (FIGS). I. Detection Method and Catalog
- 2018
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Ingår i: Astrophysical Journal. - : American Astronomical Society. - 0004-637X .- 1538-4357. ; 868:1
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Tidskriftsartikel (refereegranskat)abstract
- We present the results from the application of a two-dimensional emission line detection method, EMission-line two-Dimensional (EM2D), to the near-infrared G102 grism observations obtained with the Wide-Field Camera 3 (WFC3) as part of the Cycle 22 Hubble Space Telescope Treasury Program: the Faint Infrared Grism Survey (FIGS). Using the EM2D method, we have assembled a catalog of emission line galaxies (ELGs) with resolved star formation from each of the four FIGS fields. Not only can one better assess the global properties of ELGs, but the EM2D method allows for the analysis and improved study of the individual emission-line region within each galaxy. This paper includes a description of the methodology, advantages, and the first results of the EM2D method applied to ELGs in FIGS. The advantage of 2D emission line measurements includes significant improvement of galaxy redshift measurements, approaching the level of accuracy seen in high-spectral-resolution data, but with greater efficiency; and the ability to identify and measure the properties of multiple sites of star formation and over scales of similar to 1 kpc within individual galaxies out to z similar to 4. The EM2D method also significantly improves the reliability of high-redshift (z similar to 7) Ly alpha detections. Coupled with the wide field of view and high efficiency of space-based grism observations, EM2D provides a noteworthy improvement on the physical parameters that can be extracted from grism observations.
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| 7. |
- Pirzkal, Norbert, et al.
(författare)
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FIGS-Faint Infrared Grism Survey : Description and Data Reduction
- 2017
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Ingår i: Astrophysical Journal. - : American Astronomical Society. - 0004-637X .- 1538-4357. ; 846:1
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Tidskriftsartikel (refereegranskat)abstract
- The Faint Infrared Grism Survey (FIGS) is a deep Hubble Space Telescope (HST) WFC3/IR (Wide Field Camera 3 Infrared) slitless spectroscopic survey of four deep fields. Two fields are located in the Great Observatories Origins Deep Survey-North (GOODS-N) area and two fields are located in the Great Observatories Origins Deep Survey-South (GOODS-S) area. One of the southern fields selected is the Hubble Ultra Deep Field. Each of these four fields were observed using the WFC3/G102 grism (0.8 mu m-1.15 mu m continuous coverage) with a total exposure time of 40 orbits (approximate to 100 kilo-seconds) per field. This reaches a 3 sigma continuum depth of approximate to 26 AB magnitudes and probes emission lines to similar to 10(-17) erg s(-1) cm(-2). This paper details the four FIGS fields and the overall observational strategy of the project. A detailed description of the Simulation Based Extraction (SBE) method used to extract and combine over 10,000 spectra of over 2000 distinct sources brighter than m(F105W) = 26.5 mag is provided. High fidelity simulations of the observations is shown to significantly improve the background subtraction process, the spectral contamination estimates, and the final flux calibration. This allows for the combination of multiple spectra to produce a final high quality, deep, 1D spectra for each object in the survey.
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| 8. |
- Wu, Shi-Wei, et al.
(författare)
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The massive stellar population of W49 : A spectroscopic survey
- 2016
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Ingår i: Astronomy and Astrophysics. - : EDP Sciences. - 0004-6361 .- 1432-0746. ; 589
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Tidskriftsartikel (refereegranskat)abstract
- Context. Massive stars form on different scales that range from large, dispersed OB associations to compact, dense starburst clusters. The complex structure of regions of massive star formation and the involved short timescales provide a challenge for our understanding of their birth and early evolution. As one of the most massive and luminous star-forming region in our Galaxy, W49 is the ideal place to study the formation of the most massive stars. Aims. By classifying the massive young stars that are deeply embedded in the molecular cloud of W49, we aim to investigate and trace the star formation history of this region. Methods. We analyse near-infrared K-band spectroscopic observations of W49 from LBT/LUCI combined with JHK images obtained with NTT/SOFI and LBT/LUCI. Based on JHK-band photometry and K-band spectroscopy, the massive stars are placed in a Hertzsprung Russell diagram. By comparison with evolutionary models, their age and hence the star formation history of W49 can be investigated. Results. Fourteen O-type stars, as well as two young stellar objects (YSOs), are identified by our spectroscopic survey. Eleven O stars are main sequence stars with subtypes ranging from O3 to O9.5 and masses ranging from similar to 20 M-circle dot to similar to 120 M-circle dot. Three of the O stars show strong wind features and are considered to be Of-type supergiants with masses beyond 100 M-circle dot. The two YSOs show CO emission, which is indicative of the presence of circumstellar disks in the central region of the massive cluster. The age of the cluster is estimated as similar to 1.5 Myr, with star formation continuing in different parts of the region. The ionising photons from the central massive stars have not yet cleared the molecular cocoon surrounding the cluster. W49 is comparable to extragalactic star-forming regions, and it provides us with a unique chance to study a starburst in detail.
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