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DOE OSTI · 3009989

The effects of continuum fitting on Lyman-α forest correlations

Busca, Nicolas [Sorbonne Univ., Paris (France); Centre National de la Recherche Scientifique (CNRS), Paris (France). Inst. National de Physique Nucleaire et de Physique des Particules (IN2P3), Laboratoire de Physique Nucléaire et de Hautes Energies (LPNHE); DESI Collaboration. et al.]·Rich, James (ORCID:0009000327779317)·Bautista, Julian·Cuceu, Andrei·Font-Ribera, Andreu·Guy, Julien·Herrera-Alcantar, Hiram K.·Stermer, Julianna·Balland, Christophe·Aguilar, J.·Ahlen, S.·Bianchi, D.·Brooks, D.·Claybaugh, T.·de la Macorra, A.·Doel, P.·Ferraro, S.·Forero-Romero, J.E.·Gaztañaga, E.·Gordon, C.·Gutierrez, G.·Ishak, M.·Kehoe, R.·Kirkby, D.·Kremin, A.·Landriau, M.·Le Guillou, L.·Magneville, C.·Martini, P.·Miquel, R.·Nadathur, S.·Palanque-Delabrouille, N.·Prada, F.·Pérez-Ràfols, I.·Ravoux, C.·Rossi, G.·Sanchez, E.·Schlegel, D.·Seo, H.·Silber, J.·Sprayberry, D.·Tarlé, G.·Weaver, B.A.·Zhou, R.·Zou, H.
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Abstract

Correlations of fluctuations of the flux in Lyman-α forests of high-redshift quasars have been observed by the Baryonic Acoustic Oscillation Spectroscopy Survey (BOSS) and the Dark Energy Spectroscopy Instrument (DESI) survey where they have revealed the effects of baryon acoustic oscillations (BAO). In order to fit the correlation functions to a physical model and thereby constrain cosmological parameters, it is necessary to take into account the effects of fitting the observed spectra to a template about which the fluctuations are measured. In this paper we use mock spectra to test the distortion matrix technique that has been used since the final BOSS data release to appropriately distort the models. We show that while percent-level effects on the derived forest bias parameters may be present, the technique works sufficiently well that the determination of the BAO peak position is not affected at the percent level. We introduce modifications in the technique used by DESI that were not in the original applications and suggest further possibilities for improvements.

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Busca, Nicolas [Sorbonne Univ., Paris (France); Centre National de la Recherche Scientifique (CNRS), Paris (France). Inst. National de Physique Nucleaire et de Physique des Particules (IN2P3), Laboratoire de Physique Nucléaire et de Hautes Energies (LPNHE); DESI Collaboration. et al.], Rich, James (ORCID:0009000327779317), Bautista, Julian, Cuceu, Andrei, Font-Ribera, Andreu, Guy, Julien, Herrera-Alcantar, Hiram K., Stermer, Julianna, Balland, Christophe, Aguilar, J., Ahlen, S., Bianchi, D., Brooks, D., Claybaugh, T., de la Macorra, A., Doel, P., Ferraro, S., Forero-Romero, J.E., Gaztañaga, E., Gordon, C., Gutierrez, G., Ishak, M., Kehoe, R., Kirkby, D., Kremin, A., Landriau, M., Le Guillou, L., Magneville, C., Martini, P., Miquel, R., Nadathur, S., Palanque-Delabrouille, N., Prada, F., Pérez-Ràfols, I., Ravoux, C., Rossi, G., Sanchez, E., Schlegel, D., Seo, H., Silber, J., Sprayberry, D., Tarlé, G., Weaver, B.A., Zhou, R., Zou, H.. 2025-09-05. The effects of continuum fitting on Lyman-α forest correlations. https://doi.org/10.1088/1475-7516%2F2025%2F09%2F020

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