XQ-100: A legacy survey of one hundred 3.5 ≲z≲ 4.5 quasars observed with VLT/X-shooter

Abstract

We describe the execution and data reduction of the European Southern Observatory Large Programme "Quasars and their absorption lines: a legacy survey of the high-redshift Universe with VLT/X-shooter" (hereafter "XQ-100"). XQ-100 has produced and made publicly available a homogeneous and high-quality sample of echelle spectra of 100 quasars (QSOs) at redshifts z 3.5-4.5 observed with full spectral coverage from 315 to 2500 nm at a resolving power ranging from R ∼ 4000 to 7000, depending on wavelength. The median signal-to-noise ratios are 33, 25 and 43, as measured at rest-frame wavelengths 1700, 3000 and 3600 Å, respectively. This paper provides future users of XQ-100 data with the basic statistics of the survey, along with details of target selection, data acquisition and data reduction. The paper accompanies the public release of all data products, including 100 reduced spectra. XQ-100 is the largest spectroscopic survey to date of high-redshift QSOs with simultaneous rest-frame UV/optical coverage, and as such enables a wide range of extragalactic research, from cosmology and galaxy evolution to AGN astrophysics.

Cosmological signatures of ultralight dark matter with an axionlike potential

“…4 we show the 1-dimensional MPS (P 1D ) for the full axion potential, relative to that of the ΛCDM. The P 1D is closely related to the flux power spectrum, P F , that is the actual observable in surveys like BOSS [60], HIRES/MIKES [61] and XQ100 [62]. For reference we have included horizontal lines at the approximate precision at which such experiments can prove the P 1D , and the k-range they cover.…”

“…(green lines). For reference we have included horizontal lines indicating the rough precision of current data from BOSS [60], HIRES/MIKES [61] and XQ100 [62] to show that this can be used to constraint both parameters m φ and λ.…”

Into the Ly α jungle: exploring the circumgalactic medium of galaxies at z ∼ 4−5 with MUSE

“…The data typically have a signal to noise S/N > 10 per spectral bin and we use slits of 0.9 in the optical and 0.6 in the NIR to achieve a resolution of R ∼ 8000 − 9000, sufficient to measure Lyα and accurate metallicities (Rafelski et al 2012(Rafelski et al , 2014. The X-Shooter data were reduced using standard techniques with a dedicated pipeline, as detailed in Becker et al (2012) and López et al (2016). A full description of the reduction of the X-Shooter spectrum, including sky subtraction, 1D extraction and corrections for telluric absorptions is provided in Becker et al (2019).…”

On the selection of damped Lyman α systems using Mg ii absorption at 2 < zabs < 4

“…For more details on the observations, see López et al (2016). We emphasize that the 100 QSO targets were not pre-selected to contain DLAs, thus providing a 'blind' sample of DLAs along the lines of sight.…”