SOAR Adaptive Module (SAM): Seeing Improvement with a UV Laser

Tokovinin, Andreï; Cantarutti, Rolando; Tighe, R.; Schurter, Patricio; Martinez, Manuel; Thomas, Sandrine; Bliek, N. van der

doi:10.1088/1538-3873/128/970/125003

Cited by 44 publications

(26 citation statements)

References 28 publications

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“…The CVSO 114 visual pair was not resolved in the original CVSO photometry, so we obtained high angular resolution imaging of the pair using the Southern Astrophysical Research telescope (SOAR) Adaptive Optics Module (SAM; Tokovinin et al 2016). SAM contains a 4K × 4K CCD imager covering a 3 × 3 .…”

Section: Soar Adaptive Optics Imagingmentioning

confidence: 99%

The Evolution of Protoplanetary Disks: Probing the Inner Disk of Very Low Accretors

Thanathibodee

Calvet

Herczeg

et al. 2018

ApJ

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We report FUV, optical, and NIR observations of three T Tauri stars in the Orion OB1b subassociation with Hα equivalent widths consistent with low or absent accretion and various degrees of excess flux in the mid-infrared. We aim to search for evidence of gas in the inner disk in HST ACS/SBC spectra, and to probe the accretion flows onto the star using Hα and He I λ10830 in spectra obtained at the Magellan and SOAR telescopes. At the critical age of 5 Myr, the targets are at different stages of disk evolution. One of our targets is clearly accreting, as shown by redshifted absorption at free-fall velocities in the He I line and wide wings in Hα; however, a marginal detection of FUV H 2 suggests that little gas is present in the inner disk, although the spectral energy distribution indicates that small dust still remains close to the star. Another target is surrounded by a transitional disk, with an inner cavity in which little sub-micron dust remains. Still, the inner disk shows substantial amounts of gas, accreting onto the star at a probably low, but uncertain rate. The third target lacks both a He I line or FUV emission, consistent with no accretion or inner gas disk; its very weak IR excess is consistent with a debris disk. Different processes occurring in targets with ages close to the disk dispersal time suggest that the end of accretion phase is reached in diverse ways.

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Section: Soar Adaptive Optics Imagingmentioning

confidence: 99%

The Evolution of Protoplanetary Disks: Probing the Inner Disk of Very Low Accretors

Thanathibodee

Calvet

Herczeg

et al. 2018

ApJ

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“…SAM is a ground-layer adaptive optics system correcting atmospheric turbulence near the ground. Technical details of the instrument can be found in Tokovinin et al (2016). SAMI provides a field-of-view (FOV) of 3×3 arcmin 2 with a pixel scale of 0.091 when used with a 2×2 binning.…”

Section: Soar/sami Observationsmentioning

confidence: 99%

A likely runaway star cluster in the outer disc of the Large Magellanic Cloud

Piatti

Salinas

Grebel

2018

Monthly Notices of the Royal Astronomical Society

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We present results from photometric and spectroscopic data obtained with SOAR and Gemini observatory facilities in the field of a recently discovered star cluster. The cluster, projected towards the Eastern side of the outer disc of the Large Magellanic Cloud (LMC), was originally placed nearly 10 kpc behind the LMC with an age and metallicity typical of the innermost LMC star cluster population. We assigned radial velocity (RV) memberships to stars observed spectroscopically, and derived the cluster age and distance from theoretical isochrone fitting to the cluster colour-magnitude diagram. The new object turned out to be a 0.9 Gyr old outer LMC disc cluster, which possibly reached the present position after being scattered from the innermost LMC regions where it might have been born. We arrived at this conclusion by examining the spatial distribution of LMC star clusters of similar age, by comparing the derived spectroscopic metallicity with that expected for an outside-in galaxy formation scenario, by considering the cluster internal dynamical stage as inferred from its derived structural parameters and by estimating the circular velocity of a disc that rotates with the corresponding star cluster radial velocity at the cluster's deprojected distance, which resulted to be nearly 60 per cent higher than that of most of the outer LMC disc clusters.

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“…Previous GLAO demonstrations have shown successful image correction for fields of 1 − 4 with resolutions of ∼300 mas, a factor of 2 improvement over the seeing (Baranec et al 2009;Hart et al 2010;Orban de Xivry et al 2016;Arsenault et al 2017). SAM on the SOAR telescope is a facility GLAO instrument, achieving free-atmosphere limited images in I-band with a resolution of ∼500 mas over a 3 FoV (Tokovinin et al 2016). Similarly, ARGOS on the LBT is expected to improve spatial resolution by a factor of two across a 2 FoV (Gässler et al 2012).…”

Section: Introductionmentioning

confidence: 99%

Improved Image Quality over 10′ Fields with the ʻImaka Ground-layer Adaptive Optics Experiment

Abdurrahman

Chun

et al. 2018

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Imaka is a ground layer adaptive optics (GLAO) demonstrator on the University of Hawaii 2.2m telescope with a 24 × 18 field-of-view, nearly an order of magnitude larger than previous AO instruments. In 15 nights of observing with natural guide star asterisms ∼ 16 in diameter, we measure median AO-off and AO-on empirical full-widths at half-maximum (FWHM) of 0. 95 and 0. 64 in R-band, 0. 81 and 0. 48 in I-band, and 0. 76 and 0. 44 at 1 micron. This factor of 1.5-1.7 reduction in the size of the point spread function (PSF) results from correcting both the atmosphere and telescope tracking errors. The AO-on PSF is uniform out to field positions ∼ 5 off-axis, with a typical standard deviation in the FWHM of 0. 018. Images exhibit variation in FWMM by 4.5% across the field, which has been applied as a correction to the aforementioned quantities. The AO-on PSF is also 10× more stable in time compared to the AO-off PSF. In comparing the delivered image quality to proxy measurements, we find that in both AO-off and AO-on data, delivered image quality is correlated with 'imaka's telemetry, with R-band correlation coefficients of 0.68 and 0.70, respectively. At the same wavelength, the data are correlated to DIMM and MASS seeing with coefficients of 0.45 and 0.55. Our results are an essential first step to implementing facility-class, wide-field GLAO on Maunakea telescopes, enabling new opportunities to study extended astronomical sources, such as deep galaxy fields, nearby galaxies or star clusters, at high angular resolution.

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SOAR Adaptive Module (SAM): Seeing Improvement with a UV Laser

Cited by 44 publications

References 28 publications

The Evolution of Protoplanetary Disks: Probing the Inner Disk of Very Low Accretors

The Evolution of Protoplanetary Disks: Probing the Inner Disk of Very Low Accretors

A likely runaway star cluster in the outer disc of the Large Magellanic Cloud

Improved Image Quality over 10′ Fields with the ʻImaka Ground-layer Adaptive Optics Experiment

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