arXiv subjects

Aurelie Marcotto

Publications and source records attributed to Aurelie Marcotto.

3 recordsLinked to original sources

arXiv2023

The GRAVITY+ Project: Towards All-sky, Faint-Science, High-Contrast Near-Infrared Interferometry at the VLTI

The GRAVITY instrument has been revolutionary for near-infrared interferometry by pushing sensitivity and precision to previously unknown limits. With the upgrade of GRAVITY and the Very Large Telescope Interferometer (VLTI) in GRAVITY+, these limits will be pushed even further, with vastly improved sky coverage, as well as faint-science and high-contrast capabilities. This upgrade includes the implementation of wide-field off-axis fringe-tracking, new adaptive optics systems on all Unit Telescopes, and laser guide stars in an upgraded facility. GRAVITY+ will open up the sky to the measurement of black hole masses across cosmic time in hundreds of active galactic nuclei, use the faint stars in the Galactic centre to probe General Relativity, and enable the characterisation of dozens of young exoplanets to study their formation, bearing the promise of another scientific revolution to come at the VLTI.

astro-ph.IM↗

arXiv2011

Current results of the PERSEE testbench: the cophasing control and the polychromatic null rate

Stabilizing a nulling interferometer at a nanometric level is the key issue to obtain deep null depths. The PERSEE breadboard has been designed to study and optimize the operation of a cophased nulling bench in the most realistic disturbing environment of a space mission. This presentation focuses on the current results of the PERSEE bench. In terms of metrology, we cophased at 0.33 nm rms for the piston and 80 mas rms for the tip/tilt (0.14% of the Airy disk). A Linear Quadratic Gaussian (LQG) control coupled with an unsupervised vibration identification allows us to maintain that level of correction, even with characteristic vibrations of nulling interferometry space missions. These performances, with an accurate design and alignment of the bench, currently lead to a polychromatic unpolarised null depth of 8.9E-6 stabilized at 3E-7 on the [1.65-2.45] \mum spectral band (37% bandwidth).

astro-ph.IM↗

arXiv2011

The binary Be star δ Sco at high spectral and spatial resolution: Disk geometry and kinematics before the 2011 periastron

Classical Be stars are hot non-supergiant stars surrounded by a gaseous circumstellar disk that is responsible for the observed IR-excess and emission lines. The influence of binarity on these phenomena remains controversial. delta Sco is a binary system whose primary suddently began to exhibit the Be phenomenon at the last periastron in 2000. We want to constrain the geometry and kinematics of its circumstellar environment. We observed the star between 2007 and 2010 using spectrally-resolved interferometry with the VLTI/AMBER and CHARA/VEGA instruments. We found orbital elements that are compatible with previous estimates. The next periastron should take place around July 5, 2011 (+- 4,days). We resolved the circumstellar disk in the HAlpha (FWHM = 4.8+-1.5mas), BrGamma (FWHM = 2.9 0.,mas), and the 2.06$ μ$m HeI (FWHM = 2.4+-0.3mas) lines as well as in the K band continuum (FWHM ~2.4mas). The disk kinematics are dominated by the rotation, with a disk expansion velocity on the order of 0.2km/s. The rotation law within the disk is compatible with Keplerian rotation. As the star probably rotates at about 70% of its critical velocity the ejection of matter doesn't seems to be dominated by rotation. However, the disk geometry and kinematics are similar to that of the previously studied quasi-critically rotating Be stars, namely Alpha Ara, Psi Per and 48 Per.

astro-ph.SR↗