TY - JOUR
T1 - Constraints on the spacetime variation of the fine-structure constant using DESI emission-line galaxies
AU - The DESI Collaboration
AU - Jiang, Linhua
AU - Pan, Zhiwei
AU - Aguilar, Jessica Nicole
AU - Ahlen, Steven
AU - Blum, Robert
AU - Brooks, David
AU - Claybaugh, Todd
AU - de la Macorra, Axel
AU - Dey, Arjun
AU - Doel, Peter
AU - Fanning, Kevin
AU - Ferraro, Simone
AU - Forero-Romero, Jaime E.
AU - Gaztañaga, Enrique
AU - A Gontcho, Satya Gontcho
AU - Gutierrez, Gaston
AU - Honscheid, Klaus
AU - Juneau, Stephanie
AU - Landriau, Martin
AU - Le Guillou, Laurent
AU - Levi, Michael
AU - Manera, Marc
AU - Miquel, Ramon
AU - Moustakas, John
AU - Mueller, Eva Maria
AU - Muñoz-Gutiérrez, Andrea
AU - Myers, Adam
AU - Nie, Jundan
AU - Niz, Gustavo
AU - Poppett, Claire
AU - Prada, Francisco
AU - Rezaie, Mehdi
AU - Rossi, Graziano
AU - Sanchez, Eusebio
AU - Schlafly, Edward
AU - Schubnell, Michael
AU - Seo, Hee Jong
AU - Sprayberry, David
AU - Tarlé, Gregory
AU - Weaver, Benjamin Alan
AU - Zou, Hu
N1 - Publisher Copyright:
© 2024. The Author(s). Published by the American Astronomical Society.
PY - 2024/6/20
Y1 - 2024/6/20
N2 - We present strong constraints on the spacetime variation of the fine-structure constant α using the Dark Energy Spectroscopic Instrument (DESI). In this pilot work, we utilize ∼110,000 galaxies with strong and narrow [O iii] λ λ4959, 5007 emission lines to measure the relative variation Δα/α in space and time. The [O iii] doublet is arguably the best choice for this purpose owing to its wide wavelength separation between the two lines and its strong emission in many galaxies. Our galaxy sample spans a redshift range of 0 < z < 0.95, covering half of all cosmic time. We divide the sample into subsamples in 10 redshift bins (Δz = 0.1), and calculate Δα/α for the individual subsamples. The uncertainties of the measured Δα/α are roughly between 2 × 10−6 and 2 × 10−5. We find an apparent α variation with redshift at a level of Δα/α = (2-3) × 10−5. This is highly likely to be caused by systematics associated with wavelength calibration, since such small systematics can be caused by a wavelength distortion of 0.002-0.003 Å, which is beyond the accuracy that the current DESI data can achieve. We refine the wavelength calibration using sky lines for a small fraction of the galaxies, but this does not change our main results. We further probe the spatial variation of α in small redshift ranges, and do not find obvious, large-scale structures in the spatial distribution of Δα/α. As DESI is ongoing, we will include more galaxies, and by improving the wavelength calibration, we expect to obtain a better constraint that is comparable to the strongest current constraint.
AB - We present strong constraints on the spacetime variation of the fine-structure constant α using the Dark Energy Spectroscopic Instrument (DESI). In this pilot work, we utilize ∼110,000 galaxies with strong and narrow [O iii] λ λ4959, 5007 emission lines to measure the relative variation Δα/α in space and time. The [O iii] doublet is arguably the best choice for this purpose owing to its wide wavelength separation between the two lines and its strong emission in many galaxies. Our galaxy sample spans a redshift range of 0 < z < 0.95, covering half of all cosmic time. We divide the sample into subsamples in 10 redshift bins (Δz = 0.1), and calculate Δα/α for the individual subsamples. The uncertainties of the measured Δα/α are roughly between 2 × 10−6 and 2 × 10−5. We find an apparent α variation with redshift at a level of Δα/α = (2-3) × 10−5. This is highly likely to be caused by systematics associated with wavelength calibration, since such small systematics can be caused by a wavelength distortion of 0.002-0.003 Å, which is beyond the accuracy that the current DESI data can achieve. We refine the wavelength calibration using sky lines for a small fraction of the galaxies, but this does not change our main results. We further probe the spatial variation of α in small redshift ranges, and do not find obvious, large-scale structures in the spatial distribution of Δα/α. As DESI is ongoing, we will include more galaxies, and by improving the wavelength calibration, we expect to obtain a better constraint that is comparable to the strongest current constraint.
KW - UKRI
KW - STFC
UR - http://www.scopus.com/inward/record.url?scp=85196715779&partnerID=8YFLogxK
U2 - 10.3847/1538-4357/ad47b4
DO - 10.3847/1538-4357/ad47b4
M3 - Article
AN - SCOPUS:85196715779
SN - 0004-637X
VL - 968
JO - Astrophysical Journal
JF - Astrophysical Journal
IS - 2
M1 - 120
ER -