Mock Quasar-Lyman-α forest data-sets for the SDSS-III Baryon Oscillation Spectroscopic Survey

Bautista, Julian; Bailey, S.; Font-Ribera, Andreu; Pieri, Matthew M.; Busca, N. G.; Miralda-Escudé, Jordi; Palanque-Delabrouille, N.; Rich, J.; Dawson, Kyle; Feng, Yu; Ge, Jian; Gontcho, Satya Gontcho A; Ho, Shirley; Goff, J. M. Le; Noterdaeme, P.; Pâris, Isabelle; Rossi, Graziano; Schlegel, David J.

doi:10.1088/1475-7516/2015/05/060

Cited by 39 publications

(34 citation statements)

References 32 publications

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“…Here P( f (λ) | C q (λ)) is the probability to observe a flux f (λ) for a given continuum found by convolving the intrinsic probability (model described in [58]) with the observational resolution assumed to be Gaussian. The method uses the same publicly available pipeline picca 1 (Package for IGM Cosmological-Correlations Analyses).…”

Section: Value Added Catalogsmentioning

confidence: 99%

The one-dimensional power spectrum from the SDSS DR14 Lyα forests

Chabanier

Palanque-Delabrouille

Yèche

et al. 2019

J. Cosmol. Astropart. Phys.

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135

183

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We present a measurement of the 1D Lyα forest flux power spectrum, using the complete Baryon Oscillation Spectroscopic Survey (BOSS) and first extended-BOSS (eBOSS) quasars at z qso > 2.1, corresponding to the fourteenth data release (DR14) of the Sloan Digital Sky Survey (SDSS). Our results cover thirteen bins in redshift from z Lyα = 2.2 to 4.6, and scales up to k = 0.02 (km/s) −1 . From a parent sample of 180,413 visually inspected spectra, we selected the 43,751 quasars with the best quality; this data set improves the previous result from the ninth data release (DR9), both in statistical precision (achieving a reduction by a factor of two) and in redshift coverage. We also present a thorough investigation of identified sources of systematic uncertainties that affect the measurement. The resulting 1D power spectrum of this work is in excellent agreement with the one from the BOSS DR9 data.

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Section: Value Added Catalogsmentioning

confidence: 99%

The one-dimensional power spectrum from the SDSS DR14 Lyα forests

Chabanier

Palanque-Delabrouille

Yèche

et al. 2019

J. Cosmol. Astropart. Phys.

Self Cite

135

183

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“…However, due to numerous absorption lines in the Lyα forest, a systematic continuum placement error may still remain (particularly for low SNR spectra). To quantify this, we have used the mock quasar spectra simulated by Bautista et al (2015). They have obtained the mock spectrum in three steps: Firstly, they generated the Lyα optical depth values along the line-of-sight.…”

Section: Flux and Optical Depth Analysismentioning

confidence: 99%

Probing the Environment of High-z Quasars Using the Proximity Effect in Projected Quasar Pairs

Jalan

Chand

Srianand

2019

ApJ

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We have used spectra of 181 projected quasar pairs at separations ≤ 1.5 arcmin from the Sloan Digital Sky-Survey Data Release 12 in the redshift range of 2.5 to 3.5 to probe the proximity regions of the foreground quasars. We study the proximity effect both in the longitudinal as well as in the transverse directions, by carrying out a comparison of the Lyα absorption lines originating from the vicinity of quasars to those originating from the general inter-galactic medium at the same redshift. We found an enhancement in the transmitted flux within 4 Mpc to the quasar in the longitudinal direction. However, the trend is found to be reversed in the transverse direction. In the longitudinal direction, we derived an excess overdensity profile showing an excess up to r ≤ 5 Mpc after correcting for the quasar's ionization, taking into account the effect of low spectral resolution. This excess overdensity profile matches with the average overdensity profile in the transverse direction without applying any correction for the effect of the quasar's ionization. Among various possible interpretations, we found that the anisotropic obscuration of the quasar's ionization seems to be the most probable explanation. This is also supported by the fact that all of our foreground quasars happen to be Type-I AGNs. Finally, we constrain the average quasar's illumination along the transverse direction as compared to that along the longitudinal direction to be ≤27% (3σ confidence level).

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“…The zero-flux error may also cause an additional underestimation of metal line equivalent widths, but the relative error should be similar to the fraction of zero flux present at the bottom of the Lyα line in Figures 7 and 8, which is only a few percent. We ignore these systematic errors in this paper; future improvements on this work should use mocks of the Lyα spectra in BOSS to correct for the fraction of false DLAs in our catalog, as well as the zero-flux error (see, e.g., Bautista et al 2015).…”

Section: Analysis Of the Composite Dla Spectrummentioning

confidence: 99%

The Mean Metal-line Absorption Spectrum of Damped Lyα Systems in BOSS

Mas-Ribas

Miralda-Escudé

Pérez-Ràfols

et al. 2017

ApJ

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We study the mean absorption spectrum of the Damped Lyman alpha population at z ∼ 2.6 by stacking normalized, rest-frame shifted spectra of ∼ 27 000 DLAs from the DR12 of BOSS/SDSS-III. We measure the equivalent widths of 50 individual metal absorption lines in 5 intervals of DLA hydrogen column density, 5 intervals of DLA redshift, and overall mean equivalent widths for an additional 13 absorption features from groups of strongly blended lines. The mean equivalent width of low-ionization lines increases with N HI , whereas for high-ionization lines the increase is much weaker. The mean metal line equivalent widths decrease by a factor ∼ 1.1 − 1.5 from z ∼ 2.1 to z ∼ 3.5, with small or no differences between low-and high-ionization species. We develop a theoretical model, inspired by the presence of multiple absorption components observed in high-resolution spectra, to infer mean metal column densities from the equivalent widths of partially saturated metal lines. We apply this model to 14 low-ionization species and to AlIII, SIII, SiIII, CIV, SiIV, NV and OVI. We use an approximate derivation for separating the equivalent width contributions of several lines to blended absorption features, and infer mean equivalent widths and column densities from lines of the additional species NI, ZnII, CII * , FeIII, and SIV. Several of these mean column densities of metal lines in DLAs are obtained for the first time; their values generally agree with measurements of individual DLAs from high-resolution, high signal-to-noise ratio spectra when they are available.

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Mock Quasar-Lyman-α forest data-sets for the SDSS-III Baryon Oscillation Spectroscopic Survey

Cited by 39 publications

References 32 publications

The one-dimensional power spectrum from the SDSS DR14 Lyα forests

The one-dimensional power spectrum from the SDSS DR14 Lyα forests

Probing the Environment of High-z Quasars Using the Proximity Effect in Projected Quasar Pairs

The Mean Metal-line Absorption Spectrum of Damped Lyα Systems in BOSS

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