Technologies for Astronomical Wide-Field Adaptive Optics

Adaptive Optics (AO) can greatly enhance the resolution of astronomical images, achieving close to diffraction-limited performance in the near infrared; however there are a number of areas where significant improvements can be made, one of them being the very limited field of view that current AO systems can achieve. ‘Wide-field AO’ encompasses those techniques devised to widen the corrected field of view, from a few tens of arcseconds in ‘classical AO’ systems to several arcminutes in Multi-Object AO (MOAO). This thesis researches some topics within ‘wide-field AO’ for astronomy, concentrating its experimental work in some of the key technologies required to implement MOAO: open-loop models to run deformable mirrors (DM) in a MOAO system and a ‘Figure Sensor’ to measure the shape of a DM with required accuracy and at high-speed, in order to incorporate it into the AO control system

A First in Human Trial Implanting Microalgae Shows Safety of Photosynthetic Therapy for the Effective Treatment of Full Thickness Skin Wounds

Insufficient oxygen supply represents a relevant issue in several fields of human physiology and medicine. It has been suggested that the implantation of photosynthetic cells can provide oxygen to tissues in the absence of a vascular supply. This approach has been demonstrated to be successful in several in vitro and in vivo models; however, no data is available about their safety in human patients. Here, an early phase-1 clinical trial (ClinicalTrials.gov identifier: NCT03960164, https://clinicaltrials.gov/ct2/show/NCT03960164) is presented to evaluate the safety and feasibility of implanting photosynthetic scaffolds for dermal regeneration in eight patients with full-thickness skin wounds. Overall, this trial shows that the presence of the photosynthetic microalgae Chlamydomonas reinhardtii in the implanted scaffolds did not trigger any deleterious local or systemic immune responses in a 90 days follow-up, allowing full tissue regeneration in humans. The results presented here represent the first attempt to treat patients with photosynthetic cells, supporting the translation of photosynthetic therapies into clinics

The Brazilian Tunable Filter Imager for the SOAR Telescope

International audienceThis article presents a description of a new Tunable Filter Instrument for the SOAR telescope. The Brazilian Tunable Filter Imager (BTFI) is a highly versatile new technology to be used both in seeing-limited mode and at higher spatial fidelity using the SAM Ground-Layer Adaptive Optics facility (SOAR Adaptive Module) which is being deployed at the SOAR telescope. Such an instrument presents important new science capabilities for the SOAR astronomical community, from studies of the centers of nearby galaxies and the insterstellar medium to statistical cosmological investigations. The BTFI concept takes advantage of three new technologies. The imaging Bragg Tunable Filter (iBTF) concept utilizes Volume Phase Holographic Gratings in a double-pass configuration as a tunable filter, while a new Fabry-Perot (FP) concept involves the use of commercially available technologies which allow a single FP etalon to act over a very large range of interference orders and hence spectral resolutions. Both of these filter technologies will be used in the same instrument. The combination allows for highly versatile capabilities. Spectral resolutions spanning the range between 25 and 30,000 can be achieved in the same instrument through the use of iBTF at low resolution and scanning FPs beyond R similar to 2; 000 with some overlap in the mid-range. The third component of the new technologies deployed in BTFI is the use of EMCCDs, which allow for rapid and cyclical wavelength scanning thus mitigating the damaging effect of atmospheric variability through the acquisition of the data cube. An additional important feature of the instrument is that it has two optical channels which allow for the simultaneous recording of the narrow-band, filtered image with the remaining (complementary) broadband light. This avoids the otherwise inevitable uncertainties inherent in tunable filter imaging using a single detector, which is subject to temporal variability of the atmospheric conditions. The system was designed to supply tunable filter imaging with a field-of-view of 3' on a side, sampled at 0.12 `' for direct Nasmyth seeing-limited area spectroscopy and for SAM's visitor instrument port for GLAO-fed area spectroscopy. The instrument has seen first light, mounted on the SOAR telescope, as a visitor instrument. It is now in commissioning phase

Multiplicity dependence of light (anti-)nuclei production in p–Pb collisions at sNN=5.02 TeV

The measurement of the deuteron and anti-deuteron production in the rapidity range −1 < y < 0 as a function of transverse momentum and event multiplicity in p–Pb collisions at √sNN = 5.02 TeV is presented. (Anti-)deuterons are identified via their specific energy loss dE/dx and via their time-of- flight. Their production in p–Pb collisions is compared to pp and Pb–Pb collisions and is discussed within the context of thermal and coalescence models. The ratio of integrated yields of deuterons to protons (d/p) shows a significant increase as a function of the charged-particle multiplicity of the event starting from values similar to those observed in pp collisions at low multiplicities and approaching those observed in Pb–Pb collisions at high multiplicities. The mean transverse particle momenta are extracted from the deuteron spectra and the values are similar to those obtained for p and particles. Thus, deuteron spectra do not follow mass ordering. This behaviour is in contrast to the trend observed for non-composite particles in p–Pb collisions. In addition, the production of the rare 3He and 3He nuclei has been studied. The spectrum corresponding to all non-single diffractive p-Pb collisions is obtained in the rapidity window −1 < y < 0 and the pT-integrated yield dN/dy is extracted. It is found that the yields of protons, deuterons, and 3He, normalised by the spin degeneracy factor, follow an exponential decrease with mass number

Analysis of the apparent nuclear modification in peripheral Pb–Pb collisions at 5.02 TeV

International audienceCharged-particle spectra at midrapidity are measured in Pb–Pb collisions at the centre-of-mass energy per nucleon–nucleon pair sNN=5.02 TeV and presented in centrality classes ranging from most central (0–5%) to most peripheral (95–100%) collisions. Possible medium effects are quantified using the nuclear modification factor ( RAA ) by comparing the measured spectra with those from proton–proton collisions, scaled by the number of independent nucleon–nucleon collisions obtained from a Glauber model. At large transverse momenta ( 8<pT<20GeV/c ), the average RAA is found to increase from about 0.15 in 0–5% central to a maximum value of about 0.8 in 75–85% peripheral collisions, beyond which it falls off strongly to below 0.2 for the most peripheral collisions. Furthermore, RAA initially exhibits a positive slope as a function of pT in the 8–20 GeV/c interval, while for collisions beyond the 80% class the slope is negative. To reduce uncertainties related to event selection and normalization, we also provide the ratio of RAA in adjacent centrality intervals. Our results in peripheral collisions are consistent with a PYTHIA-based model without nuclear modification, demonstrating that biases caused by the event selection and collision geometry can lead to the apparent suppression in peripheral collisions. This explains the unintuitive observation that RAA is below unity in peripheral Pb–Pb, but equal to unity in minimum-bias p–Pb collisions despite similar charged-particle multiplicities

Anisotropic flow of identified particles in Pb-Pb collisions at sNN=5.02 {\sqrt{s}}_{\mathrm{NN}}=5.02 TeV

The elliptic (v$_{2}$), triangular (v$_{3}$), and quadrangular (v$_{4}$) flow coefficients of π$^{±}$, K$^{±}$, $\mathrm{p}+\overline{\mathrm{p}},\kern0.5em \Lambda +\overline{\Lambda},\kern0.5em {\mathrm{K}}_{\mathrm{S}}^0$ , and the ϕ-meson are measured in Pb-Pb collisions at ${\sqrt{s}}_{\mathrm{NN}}=5.02$ TeV. Results obtained with the scalar product method are reported for the rapidity range |y| < 0.5 as a function of transverse momentum, p$_{T}$, at different collision centrality intervals between 0–70%, including ultra-central (0–1%) collisions for π$^{±}$, K$^{±}$, and $\mathrm{p}+\overline{\mathrm{p}}$ . For p$_{T}$ < 3 GeV/c, the flow coefficients exhibit a particle mass dependence. At intermediate transverse momenta (3 < p$_{T}$ < 8–10 GeV/c), particles show an approximate grouping according to their type (i.e., mesons and baryons). The ϕ-meson v$_{2}$, which tests both particle mass dependence and type scaling, follows $\mathrm{p}+\overline{\mathrm{p}}$ v$_{2}$ at low p$_{T}$ and π$^{±}$ v$_{2}$ at intermediate p$_{T}$. The evolution of the shape of v$_{n}$(p$_{T}$) as a function of centrality and harmonic number n is studied for the various particle species. Flow coefficients of π$^{±}$, K$^{±}$, and $\mathrm{p}+\overline{\mathrm{p}}$ for p$_{T}$ < 3 GeV/c are compared to iEBE-VISHNU and MUSIC hydrodynamical calculations coupled to a hadronic cascade model (UrQMD). The iEBE-VISHNU calculations describe the results fairly well for p$_{T}$ < 2.5 GeV/c, while MUSIC calculations reproduce the measurements for p$_{T}$ < 1 GeV/c. A comparison to v$_{n}$ coefficients measured in Pb-Pb collisions at $\sqrt{s_{\mathrm{NN}}}=2.76$ TeV is also provided

Inclusive J/ψ\psi production in Xe–Xe collisions at sNN\sqrt{s_{\rm NN}} = 5.44 TeV

Inclusive J/$\psi$ production is studied in Xe-Xe interactions at a centre-of-mass energy per nucleon pair of $\sqrt{s_{\rm NN}}= 5.44$ TeV, using the ALICE detector at the CERN LHC. The J/$\psi$ meson is reconstructed via its decay into a muon pair, in the centre-of-mass rapidity interval $2.5<y<4$ and down to zero transverse momentum. In this Letter, the nuclear modification factors $R_{\rm AA}$ for inclusive J/$\psi$, measured in the centrality range 0-90% as well as in the centrality intervals 0-20% and 20-90% are presented. The $R_{\rm AA}$ values are compared to previously published results for Pb-Pb collisions at $\sqrt{s_{\rm NN}}= 5.02$ TeV and to the calculation of a transport model. A good agreement is found between Xe-Xe and Pb-Pb results as well as between data and the model

Real-time data processing in the ALICE High Level Trigger at the LHC

International audienceAt the Large Hadron Collider at CERN in Geneva, Switzerland, atomic nuclei are collided at ultra-relativistic energies. Many final-state particles are produced in each collision and their properties are measured by the ALICE detector. The detector signals induced by the produced particles are digitized leading to data rates that are in excess of 48 GB/s. The ALICE High Level Trigger (HLT) system pioneered the use of FPGA- and GPU-based algorithms to reconstruct charged-particle trajectories and reduce the data size in real time. The results of the reconstruction of the collision events, available online, are used for high level data quality and detector-performance monitoring and real-time time-dependent detector calibration. The online data compression techniques developed and used in the ALICE HLT have more than quadrupled the amount of data that can be stored for offline event processing