Atmospheric turbulence profiling using the SLODAR technique with ARGOS at LBT

ARGOS is the Ground Layer Adaptive Optics system of the Large Binocular Telescope, it uses three Laser Guide Stars, generated by Rayleigh backscattered light of pulsed lasers. Three Shack-Hartmann WFS measure the wavefront distortion in the Ground Layer. The SLOpe Detection And Ranging (SLODAR) is a method used to measure the turbulence profiles. Cross correlation of wavefronts gradient from multiple stars is used to estimate the relative strengths of turbulent layers at different altitudes. We present here the results on sky of the SLODAR profile on ARGOS

The Milky Way like galaxy NGC 6384 and its nuclear star cluster at high NIR spatial resolution using LBT/ARGOS commissioning data

We analyse high spatial resolution near infra-red (NIR) imaging of NGC6384, a Milky Way like galaxy, using ARGOS commissioning data at the Large Binocular Telescope (LBT). ARGOS provides a stable PSF$_{\rm FWHM}\!=\!0.2"\!-\!0.3"$ AO correction of the ground layer across the LUCI2 NIR camera $4'\!\times4'$ field by using six laser guide stars (three per telescope) and a natural guide star for tip-tilt sensing and guiding. Enabled by this high spatial resolution we analyse the structure of the nuclear star cluster (NSC) and the central kiloparsec of NGC6384. We find via 2D modelling that the NSC ($r_{\rm eff}\!\simeq\!10$pc) is surrounded by a small ($r_{\rm eff}\!\simeq\!100$pc) and a larger Sersi\'c ($r_{\rm eff}\!\simeq\!400$pc), all embedded within the NGC\,6384 large-scale boxy/X-shaped bulge and disk. This proof-of-concept study shows that with the high spatial resolution achieved by ground-layer AO we can push such analysis to distances previously only accessible from space. SED-fitting to the NIR and optical HST photometry allowed to leverage the age-metallicity-extinction degeneracies and derive the effective NSC properties of an young to old population mass ratio of $8\%$ with ${\cal M}_{\rm\star,old}\!\simeq\!3.5\times10^7M_\odot$, Age$_{\rm old,\ young}\!=\!10.9\pm1.3$Gyr and 226\,Myr$\pm62\%$, metallicity [M/H]$=\!-0.11\pm0.16$and$0.33\pm39\%$dex, and$E(B\!-\!V)\!=\!0.63$ and 1.44mag.Comment: 12 pages (+9 appendix), 11 figures, Accepted in MNRA

Performance and First Science Observations with ARGOS

Coming online for scientific operations, the ARGOS facility is boosting the imaging and spectroscopic capabilities at the LBT. With six Rayleigh laser guide stars and the corresponding wavefront sensing, ARGOS corrects the ground layer distortions for both LBT 8.4 m telescopes with its adaptive secondary mirrors. Under most conditions this setup delivers a PSF size reduction by a factor ~2-3. With the two LUCI infrared imaging and MOS spectroscopy instruments receiving the corrected images, observations in the near infrared can be performed at high spatial and spectral resolution. We will briefly discuss the final ARGOS technical setup and the adaptive optics performances. With first scientific observations been conducted, we will show that imaging cases with GLAO are nicely boosting several science programs from cluster CMD, Milky Way embedded star formation and Cepheids, BHs in nearby galaxies to extragalactic deep fields. In the unique combination of ARGOS with the multi-object NIR spectroscopy available in LUCI, first scientific observations have been performed on local and high-z objects. Those high spatial and spectral resolution observations nicely demonstrate the capabilities now at hand with ARGOS at the LBT. Inhere we describe briefly the system and show examples of science observations from nearby clusters to high redshift gravitationally lensed objects

The Discovery of a Gravitationally Lensed Quasar at z = 6.51

Strong gravitational lensing provides a powerful probe of the physical properties of quasars and their host galaxies. A high fraction of the most luminous high-redshift quasars was predicted to be lensed due to magnification bias. However, no multiple imaged quasar was found at z>5 in previous surveys. We report the discovery of J043947.08+163415.7, a strongly lensed quasar at z=6.51, the first such object detected at the epoch of reionization, and the brightest quasar yet known at z>5. High-resolution HST imaging reveals a multiple imaged system with a maximum image separation theta ~ 0.2", best explained by a model of three quasar images lensed by a low luminosity galaxy at z~0.7, with a magnification factor of ~50. The existence of this source suggests that a significant population of strongly lensed, high redshift quasars could have been missed by previous surveys, as standard color selection techniques would fail when the quasar color is contaminated by the lensing galaxy.Comment: 8 pages, 4 figures, submitted to ApJ

ELT-HIRES the High Resolution Spectrograph for the ELT: the IFU-SCAO module

We present the results from the phase A study of ELT-HIRES, an optical-infrared High Resolution Spectrograph for ELT, which has just been completed by a consortium of 30 institutes from 12 countries forming a team of about 200 scientists and engineers. The top science cases of ELT-HIRES will be the detection of life signatures from exoplanet atmospheres, tests on the stability of Nature's fundamental couplings, the direct detection of the cosmic acceleration. However, the science requirements of these science cases enable many other groundbreaking science cases. The baseline design, which allows to fulfil the top science cases, consists in a modular fiber- fed cross-dispersed echelle spectrograph with two ultra-stable spectral arms providing a simultaneous spectral range of 0.4-1.8 μm at a spectral resolution of 100,000. The fiber-feeding allows ELT-HIRES to have several, interchangeable observing modes including a SCAO module and a small diffraction-limited IFU

Assigning single clinical features to their disease-locus in large deletions: the example of chromosome 1q23-25 deletion syndrome

Aim: Assigning a disease-locus within the shortest regions of overlap (SRO) shared by deleted/duplicated subjects presenting this disease is a robust mapping approach, although the presence of different malformation traits and their attendance only in a part of the affected subjects can hinder the interpretation. To overcome the problem of incomplete penetrance, we developed an algorithm that we applied to the deletion region 1q23.3-q25, which contains three SROs, each contributing to the abnormal phenotype without clearly distinguishing between the different malformations. We describe six new subjects, including a healthy father and his daughter, with 1q23.3-q25 deletion of different sizes. The aim of this study was to correlate specific abnormal traits to the haploinsufficiency of specific gene/putative regulatory elements. Methods: Merging cases with those in the literature, we considered four traits, namely intellectual disability (ID), microcephaly, short-hands/feet, and brachydactyly, and conceived a mathematical model to predict with what probability the haploinsufficiency of a specific portion of the deletion region is associated with one of the four malformations. Results: The haploinsufficiency of PBX1 is strongly associated with ID. DNM3 and LHX4 are confirmed as responsible for growth retardation, whereas ATPIB1 was identified as a new candidate gene for microcephaly, short-hands/feet, and brachydactyly. Conclusion: Although our model is hampered by long-term position effects of regulatory elements, synergistic cooperation of several genes, and incomplete clinical assessment, it can be useful for contiguous gene syndromes showing a complex pattern of clinical characteristics. Obviously, functional approaches are needed to warrant its reliability

AOF upgrade for VLT UT4: an 8m class HST from ground

In this paper we present numerical simulations and an initial design for a visible MCAO system for the VLT-UT4 telescope. The proposed concept takes great advantage of the existing HW developed for the Adaptive Optics Facility (AOF) at the VLT-UT4, in particular the 4x20W Toptica lasers and the adaptive secondary mirror with 1170 actuators. The mentioned units makes the VLT-AOF a unique facility to develop a second generation AO system aiming to provide corrected FoV at short wavelength. In particular the flux provided by the four lasers steerable on sky and the high density of actuators (20cm equivalent on M1) provides the temporal bandwidth and the spatial sampling to push the correction down to the visible wavelengths. In addition to this the request of a reasonable size corrected FoV with uniform performance calls for an MCAO system. For such reason here we propose to complement the AOF with post-focal DMs that together with the VLT DSM can provide a corrected FoV of roughly 20/30 arcsec diameter size. An additional challenge for the system is the provided a large sky coverage. Such condition comes from the efficiency of LO wavefront sensors that use field NGS. The presented simulations give some first results for (a) the achieved performance at visible wavelength 0.4-0.9 um as a function of DMs and tip tilt NGSs characteristics (b) the achieved system sky coverage after. Pushing performance toward visible wavelengths calls for embedded and efficient post-processing methods. Being able to capture short-exposure science images (with the trade-off on noise and overheads), would allow retrieving the ultimate performance by compensating the residual turbulence aberrations left over by the AO system. Considerations about advanced analysis tools that may potentially relax the system constraints are discussed. Finally the paper presents a conceptual arrangement for the opto-mechanics of the considered AO module including the additional DMs and wavefront sensors