&lt;title&gt;Volume-phase holographic spectrograph for the Magellan telescopes&lt;/title&gt;

Bernstein, G. M.; Athey, Alex; Bernstein, R. A.; Gunnels, Steven M.; Richstone, D. O.; Shectman, Stephen

doi:10.1117/12.454281

Cited by 20 publications

(17 citation statements)

References 8 publications

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“…[27] the number of QSO spectra, at these redshifts, has improved by nearly a factor 2. Spectra for fourteen of the objects were taken with the Keck High Resolution Echelle Spectrometer (HIRES) [44], and the remaining eleven were taken with the Magellan Inamori Kyocera Echelle (MIKE) spectrograph on the Magellan Clay telescope [45]. Most of the data have been presented elsewhere [19,[46][47][48].…”

Section: Datamentioning

confidence: 99%

Warm dark matter as a solution to the small scale crisis: New constraints from high redshift Lyman-αforest data

Becker²,

et al. 2013

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We present updated constraints on the free-streaming of warm dark matter (WDM) particles derived from an analysis of the Lyman-flux power spectrum measured from high-resolution spectra of 25 z > 4 quasars obtained with the Keck High Resolution Echelle Spectrometer and the Magellan Inamori Kyocera Echelle spectrograph. We utilize a new suite of high-resolution hydrodynamical simulations that explore WDM masses of 1, 2 and 4 keV (assuming the WDM consists of thermal relics), along with different physically motivated thermal histories. We carefully address different sources of systematic error that may affect our final results and perform an analysis of the Lyman-flux power with conservative error estimates. By using a method that samples the multidimensional astrophysical and cosmological parameter space, we obtain a lower limit m WDM * 3:3 keV (2) for warm dark matter particles in the form of early decoupled thermal relics. Adding the Sloan Digital Sky Survey Lyman-flux power spectrum does not improve this limit. Thermal relics of masses 1, 2 and 2.5 keV are disfavored by the data at about the 9, 4 and 3 C.L., respectively. Our analysis disfavors WDM models where there is a suppression in the linear matter power spectrum at (nonlinear) scales corresponding to k ¼ 10h=Mpc which deviates more than 10% from a Lambda cold dark matter model. Given this limit, the corresponding ''free-streaming mass'' below which the mass function may be suppressed is $2 Â 10 8 h À1 M . There is thus very little room for a contribution of the free-streaming of WDM to the solution of what has been termed the small scale crisis of cold dark matter.

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Section: Datamentioning

confidence: 99%

Warm dark matter as a solution to the small scale crisis: New constraints from high redshift Lyman-αforest data

Becker²,

et al. 2013

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“…Using an analysis of the Lyman-α flux from the HIRES [54] and MIKE spectrographs [55], Ref. [33] obtained a bound on the free-streaming scale of a warm thermal relic, corresponding to a particle mass of m WDM 3.3 keV (or equivalently, α 0.012).…”

Section: B Large-scale Structurementioning

confidence: 99%

Constraining dark matter-neutrino interactions using the CMB and large-scale structure

Wilkinson

Bœhm

Lesgourgues

2014

J. Cosmol. Astropart. Phys.

167

213

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We present a new study on the elastic scattering cross section of dark matter (DM) and neutrinos using the latest cosmological data from Planck and large-scale structure experiments. We find that the strongest constraints are set by the Lyman-α forest, giving σ DM−ν 10 −33 (m DM /GeV) cm 2 if the cross section is constant and a present-day value of σ DM−ν 10 −45 (m DM /GeV) cm 2 if it scales as the temperature squared. These are the most robust limits on DM-neutrino interactions to date, demonstrating that one can use the distribution of matter in the Universe to probe dark ("invisible") interactions. Additionally, we show that scenarios involving thermal MeV DM and a constant elastic scattering cross section naturally predict (i) a cut-off in the matter power spectrum at the Lyman-α scale, (ii) N eff ∼ 3.5 ± 0.4, (iii) H 0 ∼ 71 ± 3 km s −1 Mpc −1 and (iv) the possible generation of neutrino masses.

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“…Note that the blaze wavelength does not depend strongly on the shape of the index modulations, which are presumed to be sinusoidal in the models. To detect the blaze wavelength, it may be necessary to change the grating-to-camera angle, as well as the collimator-to-grating angle (see Bernstein et al 2002 for an alternative approach using a pair of mirrors). A VPH 6 Low values of the average refractive index imply that voids are formed n 2 in the DCG layer during processing (Curran & Shankoff 1970;Meyerhofer 1977).…”

Section: Tuning a Vph Gratingmentioning

confidence: 99%

“…An instrument that exploits the advantages of VPH gratings can, in principle, greatly reduce systematic error in the detected signal. VPH gratings are already in use or are being brought into use in a number of spectrographs, including: LDSSϩϩ and Taurus at the Anglo-Australian Telescope ); OSIRIS at the Gran Telescopio Canarias (Cepa et al 2000); the Goodman spectrograph at the SOAR Telescope (Clemens et al 2000); M2HES at the Magellan II Telescope (Bernstein et al 2002); FORS at the Very Large Telescope (Monnet et al 2002); FOCAS at the Subaru Telescope (Ebizuka et al 2003); and LRS at the Hobby-Eberly Telescope (Hill et al 2003). The potential of VPH gratings for astronomical applications has been investigated and discussed by Barden and others (Barden et al 1998(Barden et al , 2000a(Barden et al , 2000b(Barden et al , 2002(Barden et al , 2003Robertson et al 2000;Rallison et al 2003;Tamura et al 2004).…”

Section: Introductionmentioning

confidence: 99%

Volume Phase Holographic Gratings: Polarization Properties and Diffraction Efficiency

Baldry¹,

Bland-Hawthorn²,

Robertson³

2004

PUBL ASTRON SOC PAC

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ABSTRACT. We discuss the polarization properties and first-order diffraction efficiencies of volume phase holographic (VPH) transmission gratings, which can be exploited to improve the throughput of modern spectrographs. The wavelength of peak efficiency can be tuned by adjustment of the incidence angle. We show that the variation of the Kogelnik efficiency versus Bragg angle depends only on one parameter, given by , where is semiamplitude of the refractive index modulation, n is the average index, d is P p (Dnd)/(nL) Dn tune the thickness of the active layer, and L is the grating period. The efficiency has a well-defined dependence on polarization. In particular, it is possible to obtain theoretical 100% diffraction efficiency with one linear polarization at any angle, or to obtain 100% efficiency with unpolarized light at specific angles. In the latter case, high efficiency is the result of aligning the peaks of the s-and p-polarization efficiency-versus-thickness curves. The first of these "s-p-phased gratings" for astronomy is in use with the 6dF spectrograph. Consideration of polarization is particularly important for high spectral resolution, which requires large incidence angles. We also discuss the possibility of separating polarization states for improved throughput along the entire optical train of a spectrograph.

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<title>Volume-phase holographic spectrograph for the Magellan telescopes</title>

Cited by 20 publications

References 8 publications

Warm dark matter as a solution to the small scale crisis: New constraints from high redshift Lyman-αforest data

Warm dark matter as a solution to the small scale crisis: New constraints from high redshift Lyman-αforest data

Constraining dark matter-neutrino interactions using the CMB and large-scale structure

Volume Phase Holographic Gratings: Polarization Properties and Diffraction Efficiency

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