Exoplanets with ELT-METIS Bowens, R; Meyer, M R; Delacroix, C ...
Astronomy & astrophysics,
09/2021, Volume:
653
Journal Article
Peer reviewed
Open access
Direct imaging is a powerful exoplanet discovery technique that is complementary to other techniques and offers great promise in the era of 30 m class telescopes. Space-based transit surveys have ...revolutionized our understanding of the frequency of planets at small orbital radii around Sun-like stars. The next generation of extremely large ground-based telescopes will have the angular resolution and sensitivity to directly image planets with R < 4 R⊕ around the very nearest stars. Here, we predict yields from a direct imaging survey of a volume-limited sample of Sun-like stars with the Mid-Infrared ELT Imager and Spectrograph (METIS) instrument, planned for the 39 m European Southern Observatory Extremely Large Telescope (ELT) that is expected to be operational towards the end of the decade. Using Kepler occurrence rates, a sample of stars with spectral types A-K within 6.5 pc, and simulated contrast curves based on an advanced model of what is achievable from coronagraphic imaging with adaptive optics, we estimated the expected yield from METIS using Monte Carlo simulations. We find the METIS expected yield of planets in the N2 band (10.10−12.40 μm) is 1.14 planets, which is greater than comparable observations in the L (3.70−3.95 μm) and M (4.70−4.90 μm) bands. We also determined a 24.6% chance of detecting at least one Jovian planet in the background limited regime assuming a 1 h integration. We calculated the yield per star and estimate optimal observing revisit times to increase the yield. We also analyzed a northern hemisphere version of this survey and found there are additional targets worth considering. In conclusion, we present an observing strategy aimed to maximize the possible yield for limited telescope time, resulting in 1.48 expected planets in the N2 band.
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FMFMET, NUK, UL, UM, UPUK
Here we present the installation and successful commissioning of an L'-band Annular Groove Phase Mask (AGPM) coronagraph on VLT/NACO. The AGPM is a vector vortex coronagraph made from diamond ...subwavelength gratings tuned to the L' band. The vector vortex coronagraph enables high contrast imaging at very small inner working angle (here 0″.09, the diffraction limit of the VLT at L'), potentially being the key to a new parameter space. During technical and science verification runs, we discovered a late-type companion at two beamwidths from an F0V star (Mawet et al. 2013), and imaged the inner regions of β Pictoris down to the previously unexplored projected radius of 1.75 AU. The circumstellar disk was also resolved from ≃ 1″ to 5″ (see J. Milli et al., these proceedings). These results showcase the potential of the NACO L-band AGPM over a wide range of spatial scales.
Abstract
Background
Activated cardiac fibroblasts produce extracellular matrix proteins that accumulate during cardiac fibrosis. We have recently shown that PW1 is expressed in a subset of cardiac ...stromal cells and that cardiac PW1+ cells represent a cellular source of fibroblasts in the ischemic hearts.
Purpose
We aimed to further identify new cell surface markers expressed by cardiac PW1+ cells and to investigate their role in the fibrogenic behavior of these cells.
Methods and results
We first performed transcriptomic and proteomic profiling of FACS-isolated cardiac PW1+ from normal and ischemic hearts. RNA-sequencing output files were processed with bioinformatics algorithms to identify 378 specific cell-surface markers for cardiac PW1+ cells. By comparing these candidates with the proteomic profile, we then cross-identified 9 cell surface proteins primarily involved in cell motility, adhesion to the matrix, inflammatory response and response to wounding. One of these candidates (i.e., aV-integrin or CD51) was expressed in almost all cardiac PW1+ cells (93±1%), and was predominantly found in cells expressing PW1 in the myocardium. Cardiac PW1+ cells showed a predominant expression of aVβ1 complex which is known to mediate fibrosis through TGF-beta activation in a number of tissues. The transfer of isolated cardiac PW1+CD51+ cells into ischemic hearts was associated with fibrosis development. We further demonstrated that inhibition of aV-integrin in cardiac PW1+ cells reduces their profibrotic gene expression profile and their ability to differentiate into fibroblasts. Lastly, a pharmacological blockade of aV-integrin improved cardiac function and animal survival following myocardial infarction coupled with a reduced infarct size and fibrotic lesion.
Conclusions
These data identify a targetable pathway that regulates cardiac fibrosis in response to an ischemic injury and demonstrate that pharmacological inhibition of aV-integrin leads to reduced pathological outcomes following cardiac ischemia.
Acknowledgement/Funding
Fondation Leducq (grant 13CVD01, CardioStemNet project), Fédération Française de Cardiologie and Era-CVD (ANR-16-ECVD-0011-03, Clarify project)
Studies in mice have shown that the Notch3 protein plays a major role in the functional and structural plasticity of resistance arteries, angiogenesis, and contributes to the adaptation of these ...vessels to variations in loading conditions.
Our aim was to determine whether gender is a factor of the cardiac phenotype of Notch3 KO mice in the basal state and in response to a volume overload.
Two-month-old male and female C57Bl/6J WT and KO Notch3 mice were used in a moderate training protocol on treadmill with increasing speed, in order to mimic the effort induced during cardiac rehabilitation.
In basal conditions, KO mice are characterized by a low expression of VEGFR2 mRNA, leading to an arteriolar rarefaction (P<0.0002) without changes in capillary density regardless of gender. This results to a fibrosis in KO mice. However, gender differences are observed since males display cardiac hypertrophy (P<0.0001) while females have a decreased shortening fraction (P<0.0001).
In training conditions, expression of sFlt1 mRNA increased in female Notch3 KO mice. Physical training increased the capillary density only in WT males (P<0.0332) whereas, it reduced the capillary density (P<0.0021) and induced cardiac fibrosis (P<0.0021) in Notch3 KO females. In addition, physical training reversed cardiac hypertrophy (P<0.0332) in male Notch3 KO, but has no major effect in the cardiac function of female Notch3 KO.
This work highlights for the first time the gender-specific effects of Notch3 in the heart phenotype under control conditions and after moderate physical training.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
An optical vortex coronagraph has been implemented within the NIRC2 camera on the Keck II telescope and used to carry out on-sky tests and observations. The development of this new L'-band ...observational mode is described, and an initial demonstration of the new capability is presented: a resolved image of the low-mass companion to HIP79124, which had previously been detected by means of interferometry. With HIP79124 B at a projected separation of 186.5 mas, both the small inner working angle of the vortex coronagraph and the related imaging improvements were crucial in imaging this close companion directly. Due to higher Strehl ratios and more relaxed contrasts in L' band versus H band, this new coronagraphic capability will enable high-contrast small-angle observations of nearby young exoplanets and disks on a par with those of shorter-wavelength extreme adaptive optics coronagraphs.
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