Related papers: Stellar photometry with Multi Conjugate Adaptive O…

The development of adaptive optics (AO) played a major role in modern astronomy over the last three decades. By compensating for the atmospheric turbulence, these systems enable to reach the diffraction limit on large telescopes. In this…

New high-resolution adaptive optics systems provide an unprecedentedly detailed view of nearby star forming regions. In particular, young nearby T Tauri stars can be probed at much smaller physical scales (a few AU) than possible just a…

Traditional artificial-star tests are widely applied to photometry in crowded stellar fields. However, to obtain reliable binary fractions (and their uncertainties) of remote, dense, and rich star clusters, one needs to recover huge numbers…

MICADO is the adaptive optics imaging camera being studied for the E-ELT. Its design has been optimised for use with MCAO, but will have its own SCAO module for the initial operational phase; and in principle could also be used with GLAO or…

The advent of next-generation imaging telescopes such as LSST and Pan-STARRS has revitalized the need for deep and precise reference frames. The proposed weak-lensing observations with these facilities put the highest demands on image…

The finding of multiple stellar populations (MP), defined by patterns in the stellar element abundances, is nowadays considered a distinctive feature of globular clusters. However, while data availability and quality improved in last…

A multi-object spectrograph on the forthcoming European Extremely Large Telescope will be required to operate with good sky coverage. Many of the interesting deep cosmological fields were deliberately chosen to be free of bright foreground…

CONTEXT. Massive stars have high-multiplicity fractions, and many of them have still undetected components, thus hampering the study of their properties. AIMS. I study a sample of massive stars with high angular resolution to better…

Accurate astrometry is a key deliverable for the next generation of multi-conjugate adaptive optics (MCAO) systems. The MCAO Visible Imager and Spectrograph (MAVIS) is being designed for the Very Large Telescope Adaptive Optics Facility and…

We show the astrometric potential of the Wide Field Imager at the focus of the MPI-ESO 2.2m Telescope. Currently, we are able to measure the position of a well-exposed star with a precision of $\sim$4 mas/frame in each coordinate (under 0.8…

As part of the National Science Foundation funded "Gemini in the Era of MultiMessenger Astronomy" (GEMMA) program, Gemini Observatory is developing GNAO, a widefield adaptive optics (AO) facility for Gemini-North on Maunakea, the only…

We measure the angular 2-point correlation functions of galaxies in a volume limited, photometrically selected galaxy sample from the fifth data release of the Sloan Digital Sky Survey. We split the sample both by luminosity and galaxy type…

A study of aperture size effects on star cluster photometry in crowded fields is presented. Tests were performed on a sample of 285 star cluster candidates in the South-West field of the M31 galaxy disk, measured in the Local Group Galaxy…

We review astronomical results in the visible ({\lambda}<1{\mu}m) with adaptive optics. Other than a brief period in the early 1990s, there has been little astronomical science done in the visible with AO until recently. The most productive…

We present the first results from the GeMS/GSAOI Galactic Globular Cluster Survey (G4CS) of the Milky-Way globular clusters (GCs) NGC 3201 and NGC 2298. Using the Gemini South Adaptive Optics Imager (GSAOI), in tandem with the Gemini…

A sub-sampled deconvolution technique for crowded field photometry with the HST WFPC2 instrument was proposed by Butler (2000) and applied to search for optical counterparts to pulsars in globular clusters (Golden et al. 2001). Simulations…

Globular star clusters are extremely important astrophysical objects since (1) they are prime laboratories for testing stellar evolution; (2) they are ``fossils'' from the epoch of galaxy formation, and thus important cosmological tools;…

We have developed photometric techniques that can be applied to images with highly-variable backgrounds, as well as to slightly-extended objects (object size comparable to or smaller than PSF size). We have shown that ordinary stellar…

Since its beginnings, diffraction-limited ground-based adaptive optics (AO) imaging has been limited to wavelengths in the near IR ({\lambda} > 1 micron) and longer. Visible AO ({\lambda} < 1 micron) has proven to be difficult because…

The Hubble Missing Globular Cluster Survey (MGCS) has taken one of the last opportunities to complete the census of Galactic globular clusters (GCs) started by past Hubble Space Telescope (HST) programs, securing high-resolution data for 34…