E-ELT update of project and effect of change to 39m design

McPherson, Alistair M.; Spyromilio, J.; Kissler-Patig, M.; Ramsay, Suzanne; Brunetto, Enzo; Dierickx, Philippe; Cassali, Mark

doi:10.1117/12.927787

Cited by 21 publications

(16 citation statements)

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“…The next step is to constrain the impact that 22 Ne sedimentation in high-metallicity progenitors (Althaus et al 2010b) and H 2 -He CIA (Jørgensen et al 2000) have on the cooling sequences of WDs with mixed H/He atmospheric compositions (Koester 2002;Hansen & Liebert 2003). The construction plan of ELTs is already in a mature phase, with the E-ELT having just been approved for construction (McPherson et al 2012). The other two projects (TMT, GMT) are in a similar construction phase.…”

Section: Conclusion and Final Remarksmentioning

confidence: 99%

On the white dwarf cooling sequence with extremely large telescopes

Bono

Salaris

Gilmozzi

2013

A&A

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We present new diagnostics of white dwarf (WD) cooling sequences and luminosity functions (LFs) in the near-infrared (NIR) bands that will exploit the sensitivity and resolution of future extremely large telescopes. The collision-induced absorption (CIA) of molecular hydrogen causes a clearly defined blue turn-off along the WD (WDBTO) cooling sequences and a bright secondary maximum in the WD LFs. These features are independent of age over a broad age range and are minimally affected by metal abundance. This means that the NIR magnitudes of the WDBTO are very promising distance indicators. The interplay between the cooling time of progressively more massive WDs and the onset of CIA causes a red turn-off along the WD (WDRTO) cooling sequences and a well defined faint peak in the WD LFs. These features are very sensitive to the cluster age, and indeed the K-band magnitude of the faint peak increases by 0.2-0.25 mag/Gyr for ages between 10 and 14 Gyr. On the other hand, the faint peak in the optical WD LF increases in the same age range by 0.17 (V band) and 0.15 (I band) mag/Gyr. Moreover, we also suggest to use the difference in magnitude between the main sequence turn-off and either the WDBTO (optical) or the WDRTO (NIR). This age diagnostic is also independent of distance and reddening. Once again the sensitivity in the K band (0.15−0.20 mag/Gyr) is on average a factor of two higher than in the optical bands (0.10 [V band], 0.07 [I band] mag/Gyr). Finally, we also outline the use of the new diagnostics to constrain the CO phase separation upon crystallization.

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Section: Conclusion and Final Remarksmentioning

confidence: 99%

On the white dwarf cooling sequence with extremely large telescopes

Bono

Salaris

Gilmozzi

2013

A&A

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“…New scientific challenges will become achievable thanks to the future 30-40 m class telescopes such as the ESO European Extremely Large Telescope (E-ELT; McPherson et al 2012). In particular, it will be possible to track properties of first galaxies at high red-shifts (Evans et al 2008).…”

Section: Introductionmentioning

confidence: 99%

Wave-front error breakdown in laser guide star multi-object adaptive optics validated on-sky by Canary

Martin

Gendron

Rousset

et al. 2017

A&A

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Context. Canary is the multi-object adaptive optics (MOAO) on-sky pathfinder developed in the perspective of multi-object spectrograph on extremely large telescopes (ELTs). In 2013, Canary was operated on-sky at the William Herschel telescope (WHT), using three off-axis natural guide stars (NGS) and four off-axis Rayleigh laser guide stars (LGS), in open-loop, with the on-axis compensated turbulence observed with a H-band imaging camera and a Truth wave-front sensor (TS) for diagnostic purposes. Aims. Our purpose is to establish a reliable and accurate wave-front error breakdown for LGS MOAO. This will enable a comprehensive analysis of Canary on-sky results and provide tools for validating simulations of MOAO systems for ELTs. Methods. To evaluate the MOAO performance, we compared the Canary on-sky results running in MOAO, in single conjugated adaptive optics (SCAO) and in ground layer adaptive optics (GLAO) modes, over a large set of data acquired in 2013. We provide a statistical study of the seeing. We also evaluated the wave-front error breakdown from both analytic computations, one based on a MOAO system modelling and the other on the measurements from the Canary TS. We have focussed especially on the tomographic error and we detail its vertical error decomposition. Results. We show that Canary obtained 30.1%, 21.4% and 17.1% H-band Strehl ratios in SCAO, MOAO and GLAO respectively, for median seeing conditions with 0.66 of total seeing including 0.59 at the ground. Moreover, we get 99% of correlation over 4500 samples, for any AO modes, between two analytic computations of residual phase variance. Based on these variances, we obtain a reasonable Strehl-ratio (SR) estimation when compared to the measured IR image SR. We evaluate the gain in compensation for the altitude turbulence brought by MOAO when compared to GLAO.

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“…However, it was made easier by following the procedure described in [8]. Consider N segments with one end of each segment located at 1 L…”

Section: Single-stage Rfamentioning

confidence: 99%

“…Ground-based Extremely Large Telescopes (ELTs) [1] are expected to revolutionize the field of astronomy, as they will be used to conduct detailed studies of planets orbiting other stars, super-massive black holes, dark matter, and dark energy. These telescopes will rely on state of the art adaptive optics systems to correct for atmospheric distortions.…”

Section: Introductionmentioning

confidence: 99%

Investigations of single-frequency Raman fiber amplifiers operating at 1178 nm

Dajani¹,

Vergien²,

Robin³

et al. 2013

Opt. Express

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We report on core-pumped single-stage and two-stage polarization-maintaining single-frequency Raman fiber amplifiers (RFAs). For a counter-pumped single-stage RFA, commercial-off-the shelf (COTS) single-mode fiber was utilized to generate 10 W of output power at 1178 nm through the application of a two-step thermal gradient in order to suppress SBS. The relatively high output can be explained by the Brillouin gain spectrum (BGS) of the COTS fiber. A pump-probe characterization of the BGS of the fiber provided a Brillouin gain coefficient of 1.2 × 10(-11) m/W with a FWHM of 78 MHz for the gain bandwidth. A fiber cutback study was also conducted to investigate the signal output at SBS threshold as a function of pump power for optimal length. This study revealed a linear dependence, which is in agreement with the theoretical prediction. Furthermore, we present numerical simulations indicating that substantial power scaling can be achieved by seeding at a higher power. Consequently, we constructed a two-stage RFA in order to achieve seed powers at the 1 W level. By utilizing an acoustically tailored fiber possessing a lower Brillouin gain coefficient than the COTS fiber and by seeding at higher powers, 22 W of single-frequency 1178 nm output was obtained from a counter-pumped two-stage RFA. Finally, we show that the single-frequency spectral bandwidth could not be maintained when a similar co-pumped two-stage RFA was utilized.

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E-ELT update of project and effect of change to 39m design

Cited by 21 publications

References 0 publications

On the white dwarf cooling sequence with extremely large telescopes

On the white dwarf cooling sequence with extremely large telescopes

Wave-front error breakdown in laser guide star multi-object adaptive optics validated on-sky by Canary

Investigations of single-frequency Raman fiber amplifiers operating at 1178 nm

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