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1. Synthetic spectra for Lyman-α forest analysis in the Dark Energy Spectroscopic Instrument

Author

Herrera-Alcantar, Hiram K, Muñoz-Gutiérrez, Andrea, Tan, Ting, González-Morales, Alma X, Font-Ribera, Andreu, Guy, Julien, Moustakas, John, Kirkby, David, Armengaud, E, Bault, A, Cabayol-Garcia, L, Chaves-Montero, J, Cuceu, A, de la Cruz, R, García, LÁ, Gordon, C, Iršič, V, Karaçaylı, NG, Le Goff, JM, Montero-Camacho, P, Niz, G, Pérez-Ràfols, I, Ramírez-Pérez, C, Ravoux, C, Walther, M, Aguilar, J, Ahlen, S, Brooks, D, Claybaugh, T, Dawson, K, de la Macorra, A, Doel, P, Forero-Romero, JE, Gaztañaga, E, Gontcho, S Gontcho A, Honscheid, K, Kehoe, R, Kisner, T, Landriau, M, Levi, Michael E, Manera, M, Martini, P, Meisner, A, Miquel, R, Nie, J, Palanque-Delabrouille, N, Poppett, C, Rezaie, M, Rossi, G, Sanchez, E, Seo, H, Tarlé, G, Weaver, BA, and Zhou, Z

Subjects
Nuclear and Plasma Physics, Physical Sciences, Bioengineering, Astronomical and Space Sciences, Atomic, Molecular, Nuclear, Particle and Plasma Physics, Nuclear & Particles Physics, Astronomical sciences, Particle and high energy physics
Abstract

Abstract: Synthetic data sets are used in cosmology to test analysis procedures, to verify that systematic errors are well understood and to demonstrate that measurements are unbiased. In this work we describe the methods used to generate synthetic datasets of Lyman-α quasar spectra aimed for studies with the Dark Energy Spectroscopic Instrument (DESI). In particular, we focus on demonstrating that our simulations reproduces important features of real samples, making them suitable to test the analysis methods to be used in DESI and to place limits on systematic effects on measurements of Baryon Acoustic Oscillations (BAO). We present a set of mocks that reproduce the statistical properties of the DESI early data set with good agreement. Additionally, we use a synthetic dataset to forecast the BAO scale constraining power of the completed DESI survey through the Lyman-α forest.

Published
2025

2. DESI 2024 IV: Baryon Acoustic Oscillations from the Lyman alpha forest

Author

Adame, AG, Aguilar, J, Ahlen, S, Alam, S, Alexander, DM, Alvarez, M, Alves, O, Anand, A, Andrade, U, Armengaud, E, Avila, S, Aviles, A, Awan, H, Bailey, S, Baltay, C, Bault, A, Bautista, J, Behera, J, BenZvi, S, Beutler, F, Bianchi, D, Blake, C, Blum, R, Brieden, S, Brodzeller, A, Brooks, D, Buckley-Geer, E, Burtin, E, Calderon, R, Canning, R, Rosell, A Carnero, Cereskaite, R, Cervantes-Cota, JL, Chabanier, S, Chaussidon, E, Chaves-Montero, J, Chen, S, Chen, X, Claybaugh, T, Cole, S, Cuceu, A, Davis, TM, Dawson, K, de la Cruz, R, de la Macorra, A, de Mattia, A, Deiosso, N, Dey, A, Dey, B, Ding, J, Ding, Z, Doel, P, Edelstein, J, Eftekharzadeh, S, Eisenstein, DJ, Elliott, A, Fagrelius, P, Fanning, K, Ferraro, S, Ereza, J, Findlay, N, Flaugher, B, Font-Ribera, A, Forero-Sánchez, D, Forero-Romero, JE, Garcia-Quintero, C, Gaztañaga, E, Gil-Marín, H, Gontcho, S Gontcho A, Gonzalez-Morales, AX, Gonzalez-Perez, V, Gordon, C, Green, D, Gruen, D, Gsponer, R, Gutierrez, G, Guy, J, Hadzhiyska, B, Hahn, C, Hanif, MMS, Herrera-Alcantar, HK, Honscheid, K, Howlett, C, Huterer, D, Iršič, V, Ishak, M, Juneau, S, Karaçaylı, NG, Kehoe, R, Kent, S, Kirkby, D, Kremin, A, Krolewski, A, Lai, Y, Lan, T-W, Landriau, M, Lang, D, Lasker, J, Le Goff, JM, and Le Guillou, L

Subjects
Particle and High Energy Physics, Astronomical Sciences, Physical Sciences, Astronomical and Space Sciences, Atomic, Molecular, Nuclear, Particle and Plasma Physics, Nuclear & Particles Physics, Astronomical sciences, Particle and high energy physics
Abstract

Abstract: We present the measurement of Baryon Acoustic Oscillations (BAO) from the Lyman-α (Lyα) forest of high-redshift quasars with the first-year dataset of the Dark Energy Spectroscopic Instrument (DESI). Our analysis uses over 420 000 Lyα forest spectra and their correlation with the spatial distribution of more than 700 000 quasars. An essential facet of this work is the development of a new analysis methodology on a blinded dataset. We conducted rigorous tests using synthetic data to ensure the reliability of our methodology and findings before unblinding. Additionally, we conducted multiple data splits to assess the consistency of the results and scrutinized various analysis approaches to confirm their robustness. For a given value of the sound horizon (rd ), we measure the expansion at z eff = 2.33 with 2% precision, H(z eff) = ( 239.2 ± 4.8 ) (147.09 Mpc /rd ) km/s/Mpc. Similarly, we present a 2.4% measurement of the transverse comoving distance to the same redshift, DM (z eff) = ( 5.84 ± 0.14 ) (rd /147.09 Mpc) Gpc. Together with other DESI BAO measurements at lower redshifts, these results are used in a companion paper to constrain cosmological parameters.

Published
2025

3. DESI 2024 VII: Cosmological Constraints from the Full-Shape Modeling of Clustering Measurements

Author

DESI Collaboration, Adame, A. G., Aguilar, J., Ahlen, S., Alam, S., Alexander, D. M., Prieto, C. Allende, Alvarez, M., Alves, O., Anand, A., Andrade, U., Armengaud, E., Avila, S., Aviles, A., Awan, H., Bahr-Kalus, B., Bailey, S., Baltay, C., Bault, A., Behera, J., BenZvi, S., Beutler, F., Bianchi, D., Blake, C., Blum, R., Bonici, M., Brieden, S., Brodzeller, A., Brooks, D., Buckley-Geer, E., Burtin, E., Calderon, R., Canning, R., Rosell, A. Carnero, Cereskaite, R., Cervantes-Cota, J. L., Chabanier, S., Chaussidon, E., Chaves-Montero, J., Chebat, D., Chen, S., Chen, X., Claybaugh, T., Cole, S., Cuceu, A., Davis, T. M., Dawson, K., de la Macorra, A., de Mattia, A., Deiosso, N., Dey, A., Dey, B., Ding, Z., Doel, P., Edelstein, J., Eftekharzadeh, S., Eisenstein, D. J., Elbers, W., Elliott, A., Fagrelius, P., Fanning, K., Ferraro, S., Ereza, J., Findlay, N., Flaugher, B., Font-Ribera, A., Forero-Sánchez, D., Forero-Romero, J. E., Frenk, C. S., Garcia-Quintero, C., Garrison, L. H., Gaztañaga, E., Gil-Marín, H., Gontcho, S. Gontcho A, Gonzalez-Morales, A. X., Gonzalez-Perez, V., Gordon, C., Green, D., Gruen, D., Gsponer, R., Gutierrez, G., Guy, J., Hadzhiyska, B., Hahn, C., Hanif, M. M. S, Herrera-Alcantar, H. K., Honscheid, K., Howlett, C., Huterer, D., Iršič, V., Ishak, M., Joyce, R., Juneau, S., Karaçaylı, N. G., Kehoe, R., Kent, S., Kirkby, D., Kong, H., Koposov, S. E., Kremin, A., Krolewski, A., Lahav, O., Lai, Y., Lan, T. -W., Landriau, M., Lang, D., Lasker, J., Goff, J. M. Le, Guillou, L. Le, Leauthaud, A., Levi, M. E., Li, T. S., Lodha, K., Magneville, C., Manera, M., Margala, D., Martini, P., Matthewson, W., Maus, M., McDonald, P., Medina-Varela, L., Meisner, A., Mena-Fernández, J., Miquel, R., Moon, J., Moore, S., Moustakas, J., Mudur, N., Mueller, E., Muñoz-Gutiérrez, A., Myers, A. D., Nadathur, S., Napolitano, L., Neveux, R., Newman, J. A., Nguyen, N. M., Nie, J., Niz, G., Noriega, H. E., Padmanabhan, N., Paillas, E., Palanque-Delabrouille, N., Pan, J., Penmetsa, S., Percival, W. J., Pieri, M. M., Pinon, M., Poppett, C., Porredon, A., Prada, F., Pérez-Fernández, A., Pérez-Ràfols, I., Rabinowitz, D., Raichoor, A., Ramírez-Pérez, C., Ramirez-Solano, S., Rashkovetskyi, M., Ravoux, C., Rezaie, M., Rich, J., Rocher, A., Rockosi, C., Roe, N. A., Rosado-Marin, A., Ross, A. J., Rossi, G., Ruggeri, R., Ruhlmann-Kleider, V., Samushia, L., Sanchez, E., Saulder, C., Schlafly, E. F., Schlegel, D., Schubnell, M., Seo, H., Shafieloo, A., Sharples, R., Silber, J., Slosar, A., Smith, A., Sprayberry, D., Tan, T., Tarlé, G., Taylor, P., Trusov, S., Vaisakh, R., Valcin, D., Valdes, F., Valogiannis, G., Vargas-Magaña, M., Verde, L., Walther, M., Wang, B., Wang, M. S., Weaver, B. A., Weaverdyck, N., Wechsler, R. H., Weinberg, D. H., White, M., Wilson, M. J., Yi, L., Yu, J., Yu, Y., Yuan, S., Yèche, C., Zaborowski, E. A., Zarrouk, P., Zhang, H., Zhao, C., Zhao, R., Zhou, R., Zhuang, T., and Zou, H.

Subjects
Astrophysics - Cosmology and Nongalactic Astrophysics
Abstract

We present cosmological results from the measurement of clustering of galaxy, quasar and Lyman-$\alpha$ forest tracers from the first year of observations with the Dark Energy Spectroscopic Instrument (DESI Data Release 1). We adopt the full-shape (FS) modeling of the power spectrum, including the effects of redshift-space distortions, in an analysis which has been validated in a series of supporting papers. In the flat $\Lambda$CDM cosmological model, DESI (FS+BAO), combined with a baryon density prior from Big Bang Nucleosynthesis and a weak prior on the scalar spectral index, determines matter density to $\Omega_\mathrm{m}=0.2962\pm 0.0095$, and the amplitude of mass fluctuations to $\sigma_8=0.842\pm 0.034$. The addition of the cosmic microwave background (CMB) data tightens these constraints to $\Omega_\mathrm{m}=0.3056\pm 0.0049$ and $\sigma_8=0.8121\pm 0.0053$, while further addition of the the joint clustering and lensing analysis from the Dark Energy Survey Year-3 (DESY3) data leads to a 0.4% determination of the Hubble constant, $H_0 = (68.40\pm 0.27)\,{\rm km\,s^{-1}\,Mpc^{-1}}$. In models with a time-varying dark energy equation of state, combinations of DESI (FS+BAO) with CMB and type Ia supernovae continue to show the preference, previously found in the DESI DR1 BAO analysis, for $w_0>-1$ and $w_a<0$ with similar levels of significance. DESI data, in combination with the CMB, impose the upper limits on the sum of the neutrino masses of $\sum m_\nu < 0.071\,{\rm eV}$ at 95% confidence. DESI data alone measure the modified-gravity parameter that controls the clustering of massive particles, $\mu_0=0.11^{+0.45}_{-0.54}$, while the combination of DESI with the CMB and the clustering and lensing analysis from DESY3 constrains both modified-gravity parameters, giving $\mu_0 = 0.04\pm 0.22$ and $\Sigma_0 = 0.044\pm 0.047$, in agreement with general relativity. [Abridged.], Comment: This DESI Collaboration Key Publication is part of the 2024 publication series using the first year of observations (see https://data.desi.lbl.gov/doc/papers/). 55 pages, 10 figures

Published
2024

4. DESI 2024 II: Sample Definitions, Characteristics, and Two-point Clustering Statistics

Author

DESI Collaboration, Adame, A. G., Aguilar, J., Ahlen, S., Alam, S., Alexander, D. M., Alvarez, M., Alves, O., Anand, A., Andrade, U., Armengaud, E., Avila, S., Aviles, A., Awan, H., Bailey, S., Baltay, C., Bault, A., Behera, J., BenZvi, S., Beutler, F., Bianchi, D., Blake, C., Blum, R., Brieden, S., Brodzeller, A., Brooks, D., Brown, Z., Buckley-Geer, E., Burtin, E., Calderon, R., Canning, R., Rosell, A. Carnero, Cereskaite, R., Cervantes-Cota, J. L., Chabanier, S., Chaussidon, E., Chaves-Montero, J., Chen, S., Chen, X., Claybaugh, T., Cole, S., Cuceu, A., Davis, T. M., Dawson, K., de la Macorra, A., de Mattia, A., Deiosso, N., Demina, R., Dey, A., Dey, B., Ding, Z., Doel, P., Edelstein, J., Eftekharzadeh, S., Eisenstein, D. J., Elliott, A., Fagrelius, P., Fanning, K., Ferraro, S., Ereza, J., Findlay, N., Flaugher, B., Font-Ribera, A., Forero-Sánchez, D., Forero-Romero, J. E., Frenk, C. S., Garcia-Quintero, C., Gaztañaga, E., Gil-Marín, H., Gontcho, S. Gontcho A, Gonzalez-Morales, A. X., Gonzalez-Perez, V., Gordon, C., Green, D., Gruen, D., Gsponer, R., Gutierrez, G., Guy, J., Hadzhiyska, B., Hahn, C., Hanif, M. M. S, Herrera-Alcantar, H. K., Honscheid, K., Hou, J., Howlett, C., Huterer, D., Iršič, V., Ishak, M., Juneau, S., Karaçaylı, N. G., Kehoe, R., Kent, S., Kirkby, D., Kitaura, F. -S., Kong, H., Kremin, A., Krolewski, A., Lai, Y., Lan, T. -W., Landriau, M., Lang, D., Lasker, J., Goff, J. M. Le, Guillou, L. Le, Leauthaud, A., Levi, M. E., Li, T. S., Lodha, K., Magneville, C., Manera, M., Margala, D., Martini, P., Maus, M., McDonald, P., Medina-Varela, L., Meisner, A., Mena-Fernández, J., Miquel, R., Moon, J., Moore, S., Moustakas, J., Mudur, N., Mueller, E., Muñoz-Gutiérrez, A., Myers, A. D., Nadathur, S., Napolitano, L., Neveux, R., Newman, J. A., Nguyen, N. M., Nie, J., Niz, G., Noriega, H. E., Padmanabhan, N., Paillas, E., Palanque-Delabrouille, N., Pan, J., Penmetsa, S., Percival, W. J., Pieri, M. M., Pinon, M., Poppett, C., Porredon, A., Prada, F., Pérez-Fernández, A., Pérez-Ràfols, I., Rabinowitz, D., Raichoor, A., Ramírez-Pérez, C., Ramirez-Solano, S., Rashkovetskyi, M., Ravoux, C., Rezaie, M., Rich, J., Rocher, A., Rockosi, C., Roe, N. A., Rosado-Marin, A., Ross, A. J., Rossi, G., Ruggeri, R., Ruhlmann-Kleider, V., Samushia, L., Sanchez, E., Saulder, C., Schlafly, E. F., Schlegel, D., Scholte, D., Schubnell, M., Seo, H., Sharples, R., Silber, J., Slosar, A., Smith, A., Sprayberry, D., Tan, T., Tarlé, G., Trusov, S., Vaisakh, R., Valcin, D., Valdes, F., Vargas-Magaña, M., Verde, L., Walther, M., Wang, B., Wang, M. S., Weaver, B. A., Weaverdyck, N., Wechsler, R. H., Weinberg, D. H., White, M., Wilson, M. J., Yu, J., Yu, Y., Yuan, S., Yèche, C., Zaborowski, E. A., Zarrouk, P., Zhang, H., Zhao, C., Zhao, R., Zhou, R., and Zou, H.

Subjects
Astrophysics - Cosmology and Nongalactic Astrophysics
Abstract

We present the samples of galaxies and quasars used for DESI 2024 cosmological analyses, drawn from the DESI Data Release 1 (DR1). We describe the construction of large-scale structure (LSS) catalogs from these samples, which include matched sets of synthetic reference `randoms' and weights that account for variations in the observed density of the samples due to experimental design and varying instrument performance. We detail how we correct for variations in observational completeness, the input `target' densities due to imaging systematics, and the ability to confidently measure redshifts from DESI spectra. We then summarize how remaining uncertainties in the corrections can be translated to systematic uncertainties for particular analyses. We describe the weights added to maximize the signal-to-noise of DESI DR1 2-point clustering measurements. We detail measurement pipelines applied to the LSS catalogs that obtain 2-point clustering measurements in configuration and Fourier space. The resulting 2-point measurements depend on window functions and normalization constraints particular to each sample, and we present the corrections required to match models to the data. We compare the configuration- and Fourier-space 2-point clustering of the data samples to that recovered from simulations of DESI DR1 and find they are, generally, in statistical agreement to within 2\% in the inferred real-space over-density field. The LSS catalogs, 2-point measurements, and their covariance matrices will be released publicly with DESI DR1., Comment: This DESI Collaboration Key Publication is part of the 2024 publication series using the first year of observations (see https://data.desi.lbl.gov/doc/papers/)

Published
2024

5. DESI 2024 V: Full-Shape Galaxy Clustering from Galaxies and Quasars

Author

DESI Collaboration, Adame, A. G., Aguilar, J., Ahlen, S., Alam, S., Alexander, D. M., Alvarez, M., Alves, O., Anand, A., Andrade, U., Armengaud, E., Avila, S., Aviles, A., Awan, H., Bailey, S., Baltay, C., Bault, A., Behera, J., BenZvi, S., Beutler, F., Bianchi, D., Blake, C., Blum, R., Brieden, S., Brodzeller, A., Brooks, D., Buckley-Geer, E., Burtin, E., Calderon, R., Canning, R., Rosell, A. Carnero, Cereskaite, R., Cervantes-Cota, J. L., Chabanier, S., Chaussidon, E., Chaves-Montero, J., Chen, S., Chen, X., Claybaugh, T., Cole, S., Cuceu, A., Davis, T. M., Dawson, K., de la Macorra, A., de Mattia, A., Deiosso, N., Dey, A., Dey, B., Ding, Z., Doel, P., Edelstein, J., Eftekharzadeh, S., Eisenstein, D. J., Elliott, A., Fagrelius, P., Fanning, K., Ferraro, S., Ereza, J., Findlay, N., Flaugher, B., Font-Ribera, A., Forero-Sánchez, D., Forero-Romero, J. E., Garcia-Quintero, C., Garrison, L. H., Gaztañaga, E., Gil-Marín, H., Gontcho, S. Gontcho A, Gonzalez-Morales, A. X., Gonzalez-Perez, V., Gordon, C., Green, D., Gruen, D., Gsponer, R., Gutierrez, G., Guy, J., Hadzhiyska, B., Hahn, C., Hanif, M. M. S, Herrera-Alcantar, H. K., Honscheid, K., Howlett, C., Huterer, D., Iršič, V., Ishak, M., Juneau, S., Karaçaylı, N. G., Kehoe, R., Kent, S., Kirkby, D., Kong, H., Koposov, S. E., Kremin, A., Krolewski, A., Lai, Y., Lan, T. -W., Landriau, M., Lang, D., Lasker, J., Goff, J. M. Le, Guillou, L. Le, Leauthaud, A., Levi, M. E., Li, T. S., Lodha, K., Magneville, C., Manera, M., Margala, D., Martini, P., Maus, M., McDonald, P., Medina-Varela, L., Meisner, A., Mena-Fernández, J., Miquel, R., Moon, J., Moore, S., Moustakas, J., Mueller, E., Muñoz-Gutiérrez, A., Myers, A. D., Nadathur, S., Napolitano, L., Neveux, R., Newman, J. A., Nguyen, N. M., Nie, J., Niz, G., Noriega, H. E., Padmanabhan, N., Paillas, E., Palanque-Delabrouille, N., Pan, J., Penmetsa, S., Percival, W. J., Pieri, M. M., Pinon, M., Poppett, C., Porredon, A., Prada, F., Pérez-Fernández, A., Pérez-Ràfols, I., Rabinowitz, D., Raichoor, A., Ramírez-Pérez, C., Ramirez-Solano, S., Rashkovetskyi, M., Ravoux, C., Rezaie, M., Rich, J., Rocher, A., Rockosi, C., Rodríguez-Martínez, F., Roe, N. A., Rosado-Marin, A., Ross, A. J., Rossi, G., Ruggeri, R., Ruhlmann-Kleider, V., Samushia, L., Sanchez, E., Saulder, C., Schlafly, E. F., Schlegel, D., Schubnell, M., Seo, H., Sharples, R., Silber, J., Slosar, A., Smith, A., Sprayberry, D., Tan, T., Tarlé, G., Trusov, S., Vaisakh, R., Valcin, D., Valdes, F., Vargas-Magaña, M., Verde, L., Walther, M., Wang, B., Wang, M. S., Weaver, B. A., Weaverdyck, N., Wechsler, R. H., Weinberg, D. H., White, M., Wilson, M. J., Yu, J., Yu, Y., Yuan, S., Yèche, C., Zaborowski, E. A., Zarrouk, P., Zhang, H., Zhao, C., Zhao, R., Zhou, R., and Zou, H.

Subjects
Astrophysics - Cosmology and Nongalactic Astrophysics
Abstract

We present the measurements and cosmological implications of the galaxy two-point clustering using over 4.7 million unique galaxy and quasar redshifts in the range $0.1

Published
2024

6. DESI 2024 VI: Cosmological Constraints from the Measurements of Baryon Acoustic Oscillations

Author

DESI Collaboration, Adame, A. G., Aguilar, J., Ahlen, S., Alam, S., Alexander, D. M., Alvarez, M., Alves, O., Anand, A., Andrade, U., Armengaud, E., Avila, S., Aviles, A., Awan, H., Bahr-Kalus, B., Bailey, S., Baltay, C., Bault, A., Behera, J., BenZvi, S., Bera, A., Beutler, F., Bianchi, D., Blake, C., Blum, R., Brieden, S., Brodzeller, A., Brooks, D., Buckley-Geer, E., Burtin, E., Calderon, R., Canning, R., Rosell, A. Carnero, Cereskaite, R., Cervantes-Cota, J. L., Chabanier, S., Chaussidon, E., Chaves-Montero, J., Chen, S., Chen, X., Claybaugh, T., Cole, S., Cuceu, A., Davis, T. M., Dawson, K., de la Macorra, A., de Mattia, A., Deiosso, N., Dey, A., Dey, B., Ding, Z., Doel, P., Edelstein, J., Eftekharzadeh, S., Eisenstein, D. J., Elliott, A., Fagrelius, P., Fanning, K., Ferraro, S., Ereza, J., Findlay, N., Flaugher, B., Font-Ribera, A., Forero-Sánchez, D., Forero-Romero, J. E., Frenk, C. S., Garcia-Quintero, C., Gaztañaga, E., Gil-Marín, H., Gontcho, S. Gontcho A, Gonzalez-Morales, A. X., Gonzalez-Perez, V., Gordon, C., Green, D., Gruen, D., Gsponer, R., Gutierrez, G., Guy, J., Hadzhiyska, B., Hahn, C., Hanif, M. M. S, Herrera-Alcantar, H. K., Honscheid, K., Howlett, C., Huterer, D., Iršič, V., Ishak, M., Juneau, S., Karaçaylı, N. G., Kehoe, R., Kent, S., Kirkby, D., Kremin, A., Krolewski, A., Lai, Y., Lan, T. -W., Landriau, M., Lang, D., Lasker, J., Goff, J. M. Le, Guillou, L. Le, Leauthaud, A., Levi, M. E., Li, T. S., Linder, E., Lodha, K., Magneville, C., Manera, M., Margala, D., Martini, P., Maus, M., McDonald, P., Medina-Varela, L., Meisner, A., Mena-Fernández, J., Miquel, R., Moon, J., Moore, S., Moustakas, J., Mudur, N., Mueller, E., Muñoz-Gutiérrez, A., Myers, A. D., Nadathur, S., Napolitano, L., Neveux, R., Newman, J. A., Nguyen, N. M., Nie, J., Niz, G., Noriega, H. E., Padmanabhan, N., Paillas, E., Palanque-Delabrouille, N., Pan, J., Penmetsa, S., Percival, W. J., Pieri, M. M., Pinon, M., Poppett, C., Porredon, A., Prada, F., Pérez-Fernández, A., Pérez-Ràfols, I., Rabinowitz, D., Raichoor, A., Ramírez-Pérez, C., Ramirez-Solano, S., Ravoux, C., Rashkovetskyi, M., Rezaie, M., Rich, J., Rocher, A., Rockosi, C., Roe, N. A., Rosado-Marin, A., Ross, A. J., Rossi, G., Ruggeri, R., Ruhlmann-Kleider, V., Samushia, L., Sanchez, E., Saulder, C., Schlafly, E. F., Schlegel, D., Schubnell, M., Seo, H., Shafieloo, A., Sharples, R., Silber, J., Slosar, A., Smith, A., Sprayberry, D., Tan, T., Tarlé, G., Taylor, P., Trusov, S., Ureña-López, L. A., Vaisakh, R., Valcin, D., Valdes, F., Vargas-Magaña, M., Verde, L., Walther, M., Wang, B., Wang, M. S., Weaver, B. A., Weaverdyck, N., Wechsler, R. H., Weinberg, D. H., White, M., Yu, J., Yu, Y., Yuan, S., Yèche, C., Zaborowski, E. A., Zarrouk, P., Zhang, H., Zhao, C., Zhao, R., Zhou, R., Zhuang, T., and Zou, H.

Subjects
Astrophysics - Cosmology and Nongalactic Astrophysics
Abstract

We present cosmological results from the measurement of baryon acoustic oscillations (BAO) in galaxy, quasar and Lyman-$\alpha$ forest tracers from the first year of observations from the Dark Energy Spectroscopic Instrument (DESI), to be released in the DESI Data Release 1. DESI BAO provide robust measurements of the transverse comoving distance and Hubble rate, or their combination, relative to the sound horizon, in seven redshift bins from over 6 million extragalactic objects in the redshift range $0.1-1$ and $w_a<0$. This preference is 2.6$\sigma$ for the DESI+CMB combination, and persists or grows when SN~Ia are added in, giving results discrepant with the $\Lambda$CDM model at the $2.5\sigma$, $3.5\sigma$ or $3.9\sigma$ levels for the addition of Pantheon+, Union3, or DES-SN5YR datasets respectively. For the flat $\Lambda$CDM model with the sum of neutrino mass $\sum m_\nu$ free, combining the DESI and CMB data yields an upper limit $\sum m_\nu < 0.072$ $(0.113)$ eV at 95% confidence for a $\sum m_\nu>0$ $(\sum m_\nu>0.059)$ eV prior. These neutrino-mass constraints are substantially relaxed in models beyond $\Lambda$CDM. [Abridged.], Comment: This DESI Collaboration Key Publication is part of the 2024 publication series using the first year of observations (see https://data.desi.lbl.gov/doc/papers). 68 pages, 15 figures. Version accepted for publication in JCAP

Published
2024

7. DESI 2024 IV: Baryon Acoustic Oscillations from the Lyman Alpha Forest

Author

DESI Collaboration, Adame, A. G., Aguilar, J., Ahlen, S., Alam, S., Alexander, D. M., Alvarez, M., Alves, O., Anand, A., Andrade, U., Armengaud, E., Avila, S., Aviles, A., Awan, H., Bailey, S., Baltay, C., Bault, A., Bautista, J., Behera, J., BenZvi, S., Beutler, F., Bianchi, D., Blake, C., Blum, R., Brieden, S., Brodzeller, A., Brooks, D., Buckley-Geer, E., Burtin, E., Calderon, R., Canning, R., Rosell, A. Carnero, Cereskaite, R., Cervantes-Cota, J. L., Chabanier, S., Chaussidon, E., Chaves-Montero, J., Chen, S., Chen, X., Claybaugh, T., Cole, S., Cuceu, A., Davis, T. M., Dawson, K., de la Cruz, R., de la Macorra, A., de Mattia, A., Deiosso, N., Dey, A., Dey, B., Ding, J., Ding, Z., Doel, P., Edelstein, J., Eftekharzadeh, S., Eisenstein, D. J., Elliott, A., Fagrelius, P., Fanning, K., Ferraro, S., Ereza, J., Findlay, N., Flaugher, B., Font-Ribera, A., Forero-Sánchez, D., Forero-Romero, J. E., Garcia-Quintero, C., Gaztañaga, E., Gil-Marín, H., Gontcho, S. Gontcho A, Gonzalez-Morales, A. X., Gonzalez-Perez, V., Gordon, C., Green, D., Gruen, D., Gsponer, R., Gutierrez, G., Guy, J., Hadzhiyska, B., Hahn, C., Hanif, M. M. S, Herrera-Alcantar, H. K., Honscheid, K., Howlett, C., Huterer, D., Iršič, V., Ishak, M., Juneau, S., Karaçayli, N. G., Kehoe, R., Kent, S., Kirkby, D., Kremin, A., Krolewski, A., Lai, Y., Lan, T. -W., Landriau, M., Lang, D., Lasker, J., Goff, J. M. Le, Guillou, L. Le, Leauthaud, A., Levi, M. E., Li, T. S., Linder, E., Lodha, K., Magneville, C., Manera, M., Margala, D., Martini, P., Maus, M., McDonald, P., Medina-Varela, L., Meisner, A., Mena-Fernández, J., Miquel, R., Moon, J., Moore, S., Moustakas, J., Mueller, E., Muñoz-Gutiérrez, A., Myers, A. D., Nadathur, S., Napolitano, L., Neveux, R., Newman, J. A., Nguyen, N. M., Nie, J., Niz, G., Noriega, H. E., Padmanabhan, N., Paillas, E., Palanque-Delabrouille, N., Pan, J., Penmetsa, S., Percival, W. J., Pieri, M. M., Pinon, M., Poppett, C., Porredon, A., Prada, F., Pérez-Fernández, A., Pérez-Ràfols, I., Rabinowitz, D., Raichoor, A., Ramírez-Pérez, C., Ramirez-Solano, S., Rashkovetskyi, M., Ravoux, C., Rezaie, M., Rich, J., Rocher, A., Rockosi, C., Roe, N. A., Rosado-Marin, A., Ross, A. J., Rossi, G., Ruggeri, R., Ruhlmann-Kleider, V., Samushia, L., Sanchez, E., Saulder, C., Schlafly, E. F., Schlegel, D., Schubnell, M., Seo, H., Sharples, R., Silber, J., Sinigaglia, F., Slosar, A., Smith, A., Sprayberry, D., Tan, T., Tarlé, G., Trusov, S., Vaisakh, R., Valcin, D., Valdes, F., Vargas-Magaña, M., Verde, L., Walther, M., Wang, B., Wang, M. S., Weaver, B. A., Weaverdyck, N., Wechsler, R. H., Weinberg, D. H., White, M., Yu, J., Yu, Y., Yuan, S., Yèche, C., Zaborowski, E. A., Zarrouk, P., Zhang, H., Zhao, C., Zhao, R., Zhou, R., and Zou, H.

Subjects
Astrophysics - Cosmology and Nongalactic Astrophysics
Abstract

We present the measurement of Baryon Acoustic Oscillations (BAO) from the Lyman-$\alpha$ (Ly$\alpha$) forest of high-redshift quasars with the first-year dataset of the Dark Energy Spectroscopic Instrument (DESI). Our analysis uses over $420\,000$ Ly$\alpha$ forest spectra and their correlation with the spatial distribution of more than $700\,000$ quasars. An essential facet of this work is the development of a new analysis methodology on a blinded dataset. We conducted rigorous tests using synthetic data to ensure the reliability of our methodology and findings before unblinding. Additionally, we conducted multiple data splits to assess the consistency of the results and scrutinized various analysis approaches to confirm their robustness. For a given value of the sound horizon ($r_d$), we measure the expansion at $z_{\rm eff}=2.33$ with 2\% precision, $H(z_{\rm eff}) = (239.2 \pm 4.8) (147.09~{\rm Mpc} /r_d)$ km/s/Mpc. Similarly, we present a 2.4\% measurement of the transverse comoving distance to the same redshift, $D_M(z_{\rm eff}) = (5.84 \pm 0.14) (r_d/147.09~{\rm Mpc})$ Gpc. Together with other DESI BAO measurements at lower redshifts, these results are used in a companion paper to constrain cosmological parameters., Comment: This DESI Collaboration Key Publication is part of the 2024 publication series using the first year of observations (see https://data.desi.lbl.gov/doc/papers). Minor changes in v4, version accepted for publication in JCAP

Published
2024
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8. Characterization of contaminants in the Lyman-alpha forest auto-correlation with DESI

Author

Guy, J., Gontcho, S. Gontcho A, Armengaud, E., Brodzeller, A., Cuceu, A., Font-Ribera, A., Herrera-Alcantar, H. K., Karaçaylı, N. G., Muñoz-Gutiérrez, A., Pieri, M., Pérez-Ràfols, I., Ramírez-Pérez, C., Ravoux, C., Rich, J., Walther, M., Karim, M. Abdul, Aguilar, J., Ahlen, S., Bault, A., Brooks, D., Claybaugh, T., de la Cruz, R., de la Macorra, A., Doel, P., Fanning, K., Forero-Romero, J. E., Gaztañaga, E., Gonzalez-Morales, A. X., Gutierrez, G., Hahn, C., Honscheid, K., Juneau, S., Kehoe, R., Kirkby, D., Kisner, T., Kremin, A., Lambert, A., Landriau, M., Guillou, L. Le, Manera, M., Martini, P., Meisner, A., Miquel, R., Montero-Camacho, P., Moustakas, J., Mueller, E., Myers, A. D., Nie, J., Niz, G., Palanque-Delabrouille, N., Percival, W. J., Poppett, C., Rezaie, M., Rossi, G., Sanchez, E., Schlegel, D., Schubnell, M., Seo, H., Silber, J., Sprayberry, D., Tan, T., Tarlé, G., Vargas-Magaña, M., and Zou, H.

Subjects
Astrophysics - Cosmology and Nongalactic Astrophysics
Abstract

Baryon Acoustic Oscillations can be measured with sub-percent precision above redshift two with the Lyman-alpha forest auto-correlation and its cross-correlation with quasar positions. This is one of the key goals of the Dark Energy Spectroscopic Instrument (DESI) which started its main survey in May 2021. We present in this paper a study of the contaminants to the lyman-alpha forest which are mainly caused by correlated signals introduced by the spectroscopic data processing pipeline as well as astrophysical contaminants due to foreground absorption in the intergalactic medium. Notably, an excess signal caused by the sky background subtraction noise is present in the lyman-alpha auto-correlation in the first line-of-sight separation bin. We use synthetic data to isolate this contribution, we also characterize the effect of spectro-photometric calibration noise, and propose a simple model to account for both effects in the analysis of the lyman-alpha forest. We then measure the auto-correlation of the quasar flux transmission fraction of low redshift quasars, where there is no lyman-alpha forest absorption but only its contaminants. We demonstrate that we can interpret the data with a two-component model: data processing noise and triply ionized Silicon and Carbon auto-correlations. This result can be used to improve the modeling of the lyman-alpha auto-correlation function measured with DESI., Comment: 32 pages, 12 figures

Published
2024

9. Validation of the DESI 2024 Ly$\alpha$ forest BAO analysis using synthetic datasets

Author

Cuceu, Andrei, Herrera-Alcantar, Hiram K., Gordon, Calum, Martini, Paul, Guy, Julien, Font-Ribera, Andreu, Gonzalez-Morales, Alma X., Karim, M. Abdul, Aguilar, J., Ahlen, S., Armengaud, E., Bault, A., Brooks, D., Claybaugh, T., de la Macorra, A., Doel, P., Fanning, K., Ferraro, S., Forero-Romero, J. E., Gaztañaga, E., Gontcho, S. Gontcho A, Gutierrez, G., Honscheid, K., Howlett, C., Karaçaylı, N. G., Kirkby, D., Kremin, A., Landriau, M., Goff, J. M. Le, Guillou, L. Le, Levi, M. E., Manera, M., Meisner, A., Miquel, R., Moustakas, J., Muñoz-Gutiérrez, A., Myers, A. D., Niz, G., Palanque-Delabrouille, N., Percival, W. J., Poppett, C., Prada, F., Pérez-Ràfols, I., Ramírez-Pérez, C., Ravoux, C., Rezaie, M., Rossi, G., Sanchez, E., Schlegel, D., Schubnell, M., Seo, H., Sprayberry, D., Tan, T., Tarlé, G., Vargas-Magaña, M., Walther, M., Weaver, B. A., Zhou, R., and Zou, H.

Subjects
Astrophysics - Cosmology and Nongalactic Astrophysics
Abstract

The first year of data from the Dark Energy Spectroscopic Instrument (DESI) contains the largest set of Lyman-$\alpha$ (Ly$\alpha$) forest spectra ever observed. This data, collected in the DESI Data Release 1 (DR1) sample, has been used to measure the Baryon Acoustic Oscillation (BAO) feature at redshift $z=2.33$. In this work, we use a set of 150 synthetic realizations of DESI DR1 to validate the DESI 2024 Ly$\alpha$ forest BAO measurement. The synthetic data sets are based on Gaussian random fields using the log-normal approximation. We produce realistic synthetic DESI spectra that include all major contaminants affecting the Ly$\alpha$ forest. The synthetic data sets span a redshift range $1.8

Published
2024

10. DESI 2024 III: Baryon Acoustic Oscillations from Galaxies and Quasars

Author

DESI Collaboration, Adame, A. G., Aguilar, J., Ahlen, S., Alam, S., Alexander, D. M., Alvarez, M., Alves, O., Anand, A., Andrade, U., Armengaud, E., Avila, S., Aviles, A., Awan, H., Bailey, S., Baltay, C., Bault, A., Behera, J., BenZvi, S., Beutler, F., Bianchi, D., Blake, C., Blum, R., Brieden, S., Brodzeller, A., Brooks, D., Buckley-Geer, E., Burtin, E., Calderon, R., Canning, R., Rosell, A. Carnero, Cereskaite, R., Cervantes-Cota, J. L., Chabanier, S., Chaussidon, E., Chaves-Montero, J., Chen, S., Chen, X., Claybaugh, T., Cole, S., Cuceu, A., Davis, T. M., Dawson, K., de la Macorra, A., de Mattia, A., Deiosso, N., Dey, A., Dey, B., Ding, Z., Doel, P., Edelstein, J., Eftekharzadeh, S., Eisenstein, D. J., Elliott, A., Fagrelius, P., Fanning, K., Ferraro, S., Ereza, J., Findlay, N., Flaugher, B., Font-Ribera, A., Forero-Sánchez, D., Forero-Romero, J. E., Garcia-Quintero, C., Gaztañaga, E., Gil-Marín, H., Gontcho, S. Gontcho A, Gonzalez-Morales, A. X., Gonzalez-Perez, V., Gordon, C., Green, D., Gruen, D., Gsponer, R., Gutierrez, G., Guy, J., Hadzhiyska, B., Hahn, C., Hanif, M. M. S, Herrera-Alcantar, H. K., Honscheid, K., Howlett, C., Huterer, D., Iršič, V., Ishak, M., Juneau, S., Karaçaylı, N. G., Kehoe, R., Kent, S., Kirkby, D., Kremin, A., Krolewski, A., Lai, Y., Lan, T. -W., Landriau, M., Lang, D., Lasker, J., Goff, J. M. Le, Guillou, L. Le, Leauthaud, A., Levi, M. E., Li, T. S., Linder, E., Lodha, K., Magneville, C., Manera, M., Margala, D., Martini, P., Maus, M., McDonald, P., Medina-Varela, L., Meisner, A., Mena-Fernández, J., Miquel, R., Moon, J., Moore, S., Moustakas, J., Mudur, N., Mueller, E., Muñoz-Gutiérrez, A., Myers, A. D., Nadathur, S., Napolitano, L., Neveux, R., Newman, J. A., Nguyen, N. M., Nie, J., Niz, G., Noriega, H. E., Padmanabhan, N., Paillas, E., Palanque-Delabrouille, N., Pan, J., Penmetsa, S., Percival, W. J., Pieri, M., Pinon, M., Poppett, C., Porredon, A., Prada, F., Pérez-Fernández, A., Pérez-Ràfols, I., Rabinowitz, D., Raichoor, A., Ramírez-Pérez, C., Ramirez-Solano, S., Rashkovetskyi, M., Rezaie, M., Rich, J., Rocher, A., Rockosi, C., Roe, N. A., Rosado-Marin, A., Ross, A. J., Rossi, G., Ruggeri, R., Ruhlmann-Kleider, V., Samushia, L., Sanchez, E., Saulder, C., Schlafly, E. F., Schlegel, D., Schubnell, M., Seo, H., Sharples, R., Silber, J., Slosar, A., Smith, A., Sprayberry, D., Swanson, J., Tan, T., Tarlé, G., Trusov, S., Vaisakh, R., Valcin, D., Valdes, F., Vargas-Magaña, M., Verde, L., Walther, M., Wang, B., Wang, M. S., Weaver, B. A., Weaverdyck, N., Wechsler, R. H., Weinberg, D. H., White, M., Yu, J., Yu, Y., Yuan, S., Yèche, C., Zaborowski, E. A., Zarrouk, P., Zhang, H., Zhao, C., Zhao, R., Zhou, R., and Zou, H.

Subjects
Astrophysics - Cosmology and Nongalactic Astrophysics
Abstract

We present the DESI 2024 galaxy and quasar baryon acoustic oscillations (BAO) measurements using over 5.7 million unique galaxy and quasar redshifts in the range 0.1

Published
2024

11. The Early Data Release of the Dark Energy Spectroscopic Instrument

Author

Collaboration, DESI, Adame, AG, Aguilar, J, Ahlen, S, Alam, S, Aldering, G, Alexander, DM, Alfarsy, R, Prieto, C Allende, Alvarez, M, Alves, O, Anand, A, Andrade-Oliveira, F, Armengaud, E, Asorey, J, Avila, S, Aviles, A, Bailey, S, Balaguera-Antolínez, A, Ballester, O, Baltay, C, Bault, A, Bautista, J, Behera, J, Beltran, SF, BenZvi, S, Silva, L Beraldo E, Bermejo-Climent, JR, Berti, A, Besuner, R, Beutler, F, Bianchi, D, Blake, C, Blum, R, Bolton, AS, Brieden, S, Brodzeller, A, Brooks, D, Brown, Z, Buckley-Geer, E, Burtin, E, Cabayol-Garcia, L, Cai, Z, Canning, R, Cardiel-Sas, L, Rosell, A Carnero, Castander, FJ, Cervantes-Cota, JL, Chabanier, S, Chaussidon, E, Chaves-Montero, J, Chen, S, Chen, X, Chuang, C, Claybaugh, T, Cole, S, Cooper, AP, Cuceu, A, Davis, TM, Dawson, K, de Belsunce, R, de la Cruz, R, de la Macorra, A, Della Costa, J, de Mattia, A, Demina, R, Demirbozan, U, DeRose, J, Dey, A, Dey, B, Dhungana, G, Ding, J, Ding, Z, Doel, P, Doshi, R, Douglass, K, Edge, A, Eftekharzadeh, S, Eisenstein, DJ, Elliott, A, Ereza, J, Escoffier, S, Fagrelius, P, Fan, X, Fanning, K, Fawcett, VA, Ferraro, S, Flaugher, B, Font-Ribera, A, Forero-Romero, JE, Forero-Sánchez, D, Frenk, CS, Gänsicke, BT, García, LÁ, García-Bellido, J, Garcia-Quintero, C, Garrison, LH, Gil-Marín, H, Golden-Marx, J, and Gontcho, S Gontcho A

Subjects
Astronomical Sciences, Physical Sciences, Astronomical and Space Sciences, Astronomy & Astrophysics, Astronomical sciences, Particle and high energy physics
Abstract

The Dark Energy Spectroscopic Instrument (DESI) completed its 5 month Survey Validation in 2021 May. Spectra of stellar and extragalactic targets from Survey Validation constitute the first major data sample from the DESI survey. This paper describes the public release of those spectra, the catalogs of derived properties, and the intermediate data products. In total, the public release includes good-quality spectral information from 466,447 objects targeted as part of the Milky Way Survey, 428,758 as part of the Bright Galaxy Survey, 227,318 as part of the Luminous Red Galaxy sample, 437,664 as part of the Emission Line Galaxy sample, and 76,079 as part of the Quasar sample. In addition, the release includes spectral information from 137,148 objects that expand the scope beyond the primary samples as part of a series of secondary programs. Here, we describe the spectral data, data quality, data products, Large-Scale Structure science catalogs, access to the data, and references that provide relevant background to using these spectra.

Published
2024

12. Broad absorption line quasars in the Dark Energy Spectroscopic Instrument Early Data Release

Author

Filbert, S, Martini, P, Seebaluck, K, Ennesser, L, Alexander, DM, Bault, A, Brodzeller, A, Herrera-Alcantar, HK, Montero-Camacho, P, Pérez-Ràfols, I, Ramírez-Pérez, C, Ravoux, C, Tan, T, Aguilar, J, Ahlen, S, Bailey, S, Brooks, D, Claybaugh, T, Dawson, K, de la Macorra, A, Doel, P, Fanning, K, Font-Ribera, A, Forero-Romero, JE, Gontcho A Gontcho, S, Guy, J, Kirkby, D, Kremin, A, Magneville, C, Manera, M, Meisner, A, Miquel, R, Moustakas, J, Nie, J, Percival, WJ, Prada, F, Rezaie, M, Rossi, G, Sanchez, E, Schubnell, M, Seo, H, Tarlé, G, Weaver, BA, and Zhou, Z

Subjects
Astronomical Sciences, Physical Sciences, galaxies: active, galaxies: nuclei, galaxies: quasars: absorption lines, galaxies: quasars: emission lines, catalogues, Astronomical and Space Sciences, Astronomy & Astrophysics, Astronomical sciences, Particle and high energy physics, Space sciences
Abstract

Broad absorption line (BAL) quasars are characterized by gas clouds that absorb flux at the wavelength of common quasar spectral features, although blueshifted by velocities that can exceed 0.1c. BAL features are interesting as signatures of significant feedback, yet they can also compromise cosmological studies with quasars by distorting the shape of the most prominent quasar emission lines, impacting redshift accuracy and measurements of the matter density distribution traced by the Lyman α forest. We present a catalogue of BAL quasars discovered in the Dark Energy Spectroscopic Instrument (DESI) survey Early Data Release, which were observed as part of DESI Survey Validation, as well as the first two months of the main survey. We describe our method to automatically identify BAL quasars in DESI data, the quantities we measure for each BAL, and investigate the completeness and purity of this method with mock DESI observations. We mask the wavelengths of the BAL features and re-evaluate each BAL quasar redshift, finding new redshifts which are 243 km s−1 smaller on average for the BAL quasar sample. These new, more accurate redshifts are important to obtain the best measurements of quasar clustering, especially at small scales. Finally, we present some spectra of rarer classes of BALs that illustrate the potential of DESI data to identify such populations for further study.

Published
2024

13. Measuring Fiber Positioning Accuracy and Throughput with Fiber Dithering for the Dark Energy Spectroscopic Instrument

Author

Schlafly, EF, Schlegel, D, BenZvi, S, Raichoor, A, Forero-Romero, JE, Aguilar, J, Ahlen, S, Bailey, S, Bault, A, Brooks, D, Claybaugh, T, Dawson, K, de la Macorra, A, Dey, Arjun, Doel, P, Gaztañaga, E, Gontcho, S Gontcho A, Guy, J, Hahn, C, Honscheid, K, Jimenez, J, Kent, S, Kirkby, D, Kisner, T, Kremin, A, Lambert, A, Landriau, M, Levi, ME, Manera, M, Martini, P, Meisner, A, Miquel, R, Moustakas, J, Myers, AD, Nie, J, Palanque-Delabrouille, N, Percival, WJ, Poppett, C, Prada, F, Rabinowitz, D, Rezaie, M, Rossi, G, Sanchez, E, Schubnell, M, Sharples, R, Silber, J, Tarlé, G, Weaver, BA, Zhou, Z, and Zou, H

Subjects
Particle and High Energy Physics, Astronomical Sciences, Physical Sciences, Astronomical and Space Sciences, Astronomy & Astrophysics, Astronomical sciences, Particle and high energy physics
Abstract

Highly multiplexed, fiber-fed spectroscopy is enabling surveys of millions of stars and galaxies. The performance of these surveys depends on accurately positioning fibers in the focal plane to capture target light. We describe a technique to measure the positioning accuracy of fibers by dithering fibers slightly around their ideal locations. This approach also enables measurement of the total system throughput and point-spread function delivered to the focal plane. We then apply this technique to observations from the Dark Energy Survey Instrument (DESI), and demonstrate that DESI positions fibers to within 0.″08 of their targets (5% of a fiber diameter) and achieves a system throughput within about 7% of expectations.

Published
2024

14. Measuring Fiber Positioning Accuracy and Throughput with Fiber Dithering for the Dark Energy Spectroscopic Instrument

Author

Schlafly, E. F., Schlegel, D., BenZvi, S., Raichoor, A., Forero-Romero, J. E., Aguilar, J., Ahlen, S., Bailey, S., Bault, A., Brooks, D., Claybaugh, T., Dawson, K., de la Macorra, A., Dey, Arjun, Doel, P., Gaztañaga, E., Gontcho, S. Gontcho A, Guy, J., Hahn, C., Honscheid, K., Jimenez, J., Kent, S., Kirkby, D., Kisner, T., Kremin, A., Lambert, A., Landriau, M., Levi, M. E., Manera, M., Martini, P., Meisner, A., Miquel, R., Moustakas, J., Myers, A. D., Nie, J., Palanque-Delabrouille, N., Percival, W. J., Poppett, C., Prada, F., Rabinowitz, D., Rezaie, M., Rossi, G., Sanchez, E., Schubnell, M., Sharples, R., Silber, J., Tarlé, G., Weaver, B. A., Zhou, Z., and Zou, H.

Subjects
Astrophysics - Instrumentation and Methods for Astrophysics
Abstract

Highly multiplexed, fiber-fed spectroscopy is enabling surveys of millions of stars and galaxies. The performance of these surveys depends on accurately positioning fibers in the focal plane to capture target light. We describe a technique to measure the positioning accuracy of fibers by dithering fibers slightly around their ideal locations. This approach also enables measurement of the total system throughput and point spread function delivered to the focal plane. We then apply this technique to observations from the Dark Energy Survey Instrument (DESI), and demonstrate that DESI positions fibers to within 0.08" of their targets (5% of a fiber diameter) and achieves a system throughput within about 5% of expectations., Comment: 17 pages, 9 figures

Published
2024

15. Impact of Systematic Redshift Errors on the Cross-correlation of the Lyman-$\alpha$ Forest with Quasars at Small Scales Using DESI Early Data

Author

Bault, Abby, Kirkby, David, Guy, Julien, Brodzeller, Allyson, Aguilar, J., Ahlen, S., Bailey, S., Brooks, D., Cabayol-Garcia, L., Chaves-Montero, J., Claybaugh, T., Cuceu, A., Dawson, K., de la Cruz, R., de la Macorra, A., Dey, A., Doel, P., Filbert, S., Font-Ribera, A., Forero-Romero, J. E., Gaztañaga, E., Gontcho, S. Gontcho A, Gordon, C., Herrera-Alcantar, H. K., Honscheid, K., Iršič, V., Karaçaylı, N. G., Kehoe, R., Kisner, T., Kremin, A., Lambert, A., Landriau, M., Guillou, L. Le, Levi, M. E., Manera, M., Martini, P., Meisner, A., Miquel, R., Montero-Camacho, P., Moustakas, J., Muñoz-Gutiérrez, A., Nie, J., Niz, G., Palanque-Delabrouille, N., Percival, W. J., Poppett, C., Prada, F., Pérez-Ràfols, I., Ramírez-Pérez, C., Ravoux, C., Rezaie, M., Rossi, G., Sanchez, E., Schlafly, E. F., Schlegel, D., Schubnell, M., Silber, J., Tan, T., Tarlé, G., Walther, M., Weaver, B. A., and Zhou, Z.

Subjects
Astrophysics - Cosmology and Nongalactic Astrophysics
Abstract

The Dark Energy Spectroscopic Instrument (DESI) will measure millions of quasar spectra by the end of its 5 year survey. Quasar redshift errors impact the shape of the Lyman-$\alpha$ forest correlation functions, which can affect cosmological analyses and therefore cosmological interpretations. Using data from the DESI Early Data Release and the first two months of the main survey, we measure the systematic redshift error from an offset in the cross-correlation of the Lyman-$\alpha$ forest with quasars. We find evidence for a redshift dependent bias causing redshifts to be underestimated with increasing redshift, stemming from improper modeling of the Lyman-$\alpha$ optical depth in the templates used for redshift estimation. New templates were derived for the DESI Year 1 quasar sample at $z > 1.6$ and we found the redshift dependent bias, $\Delta r_\parallel$, increased from $-1.94 \pm 0.15$ $h^{-1}$ Mpc to $-0.08 \pm 0.04$ $h^{-1}$ Mpc ($-205 \pm 15~\text{km s}^{-1}$ to $-9.0 \pm 4.0~\text{km s}^{-1}$). These new templates will be used to provide redshifts for the DESI Year 1 quasar sample., Comment: 29 pages, 9 figures, 5 tables

Published
2024
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16. Synthetic spectra for Lyman-$\alpha$ forest analysis in the Dark Energy Spectroscopic Instrument

Author

Herrera-Alcantar, Hiram K., Muñoz-Gutiérrez, Andrea, Tan, Ting, González-Morales, Alma X., Font-Ribera, Andreu, Guy, Julien, Moustakas, John, Kirkby, David, Armengaud, E., Bault, A., Cabayol-Garcia, L., Chaves-Montero, J., Cuceu, A., de la Cruz, R., García, L. Á., Gordon, C., Iršič, V., Karaçaylı, N. G., Goff, J. M. Le, Montero-Camacho, P., Niz, G., Pérez-Ràfols, I., Ramírez-Pérez, C., Ravoux, C., Walther, M., Aguilar, J., Ahlen, S., Brooks, D., Claybaugh, T., Dawson, K., de la Macorra, A., Doel, P., Forero-Romero, J. E., Gaztañaga, E., Gontcho, S. Gontcho A, Honscheid, K., Kehoe, R., Kisner, T., Landriau, M., Levi, Michael E., Manera, M., Martini, P., Meisner, A., Miquel, R., Nie, J., Palanque-Delabrouille, N., Poppett, C., Rezaie, M., Rossi, G., Sanchez, E., Seo, H., Tarlé, G., Weaver, B. A., and Zhou, Z.

Subjects
Astrophysics - Cosmology and Nongalactic Astrophysics
Abstract

Synthetic data sets are used in cosmology to test analysis procedures, to verify that systematic errors are well understood and to demonstrate that measurements are unbiased. In this work we describe the methods used to generate synthetic datasets of Lyman-$\alpha$ quasar spectra aimed for studies with the Dark Energy Spectroscopic Instrument (DESI). In particular, we focus on demonstrating that our simulations reproduces important features of real samples, making them suitable to test the analysis methods to be used in DESI and to place limits on systematic effects on measurements of Baryon Acoustic Oscillations (BAO). We present a set of mocks that reproduce the statistical properties of the DESI early data set with good agreement. Additionally, we use full survey synthetic data to forecast the BAO scale constraining power with DESI., Comment: 42 pages, 17 figures, 7 tables, JCAP accepted version

Published
2023
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17. Validation of the Scientific Program for the Dark Energy Spectroscopic Instrument

Author

Collaboration, DESI, Adame, AG, Aguilar, J, Ahlen, S, Alam, S, Aldering, G, Alexander, DM, Alfarsy, R, Prieto, C Allende, Alvarez, M, Alves, O, Anand, A, Andrade-Oliveira, F, Armengaud, E, Asorey, J, Avila, S, Aviles, A, Bailey, S, Balaguera-Antolínez, A, Ballester, O, Baltay, C, Bault, A, Bautista, J, Behera, J, Beltran, SF, BenZvi, S, Silva, L Beraldo E, Bermejo-Climent, JR, Berti, A, Besuner, R, Beutler, F, Bianchi, D, Blake, C, Blum, R, Bolton, AS, Brieden, S, Brodzeller, A, Brooks, D, Brown, Z, Buckley-Geer, E, Burtin, E, Cabayol-Garcia, L, Cai, Z, Canning, R, Cardiel-Sas, L, Rosell, A Carnero, Castander, FJ, Cervantes-Cota, JL, Chabanier, S, Chaussidon, E, Chaves-Montero, J, Chen, S, Chen, X, Chuang, C, Claybaugh, T, Cole, S, Cooper, AP, Cuceu, A, Davis, TM, Dawson, K, de Belsunce, R, de la Cruz, R, de la Macorra, A, de Mattia, A, Demina, R, Demirbozan, U, DeRose, J, Dey, A, Dey, B, Dhungana, G, Ding, J, Ding, Z, Doel, P, Doshi, R, Douglass, K, Edge, A, Eftekharzadeh, S, Eisenstein, DJ, Elliott, A, Escoffier, S, Fagrelius, P, Fan, X, Fanning, K, Fawcett, VA, Ferraro, S, Ereza, J, Flaugher, B, Font-Ribera, A, Forero-Sánchez, D, Forero-Romero, JE, Frenk, CS, Gänsicke, BT, García, LÁ, García-Bellido, J, Garcia-Quintero, C, Garrison, LH, Gil-Marín, H, Golden-Marx, J, Gontcho, S Gontcho A, and Gonzalez-Morales, AX

Subjects
Astronomical Sciences, Physical Sciences, Astronomical and Space Sciences, Astronomy & Astrophysics, Astronomical sciences, Particle and high energy physics
Abstract

The Dark Energy Spectroscopic Instrument (DESI) was designed to conduct a survey covering 14,000 deg2 over 5 yr to constrain the cosmic expansion history through precise measurements of baryon acoustic oscillations (BAO). The scientific program for DESI was evaluated during a 5 month survey validation (SV) campaign before beginning full operations. This program produced deep spectra of tens of thousands of objects from each of the stellar Milky Way Survey (MWS), Bright Galaxy Survey (BGS), luminous red galaxy (LRG), emission line galaxy (ELG), and quasar target classes. These SV spectra were used to optimize redshift distributions, characterize exposure times, determine calibration procedures, and assess observational overheads for the 5 yr program. In this paper, we present the final target selection algorithms, redshift distributions, and projected cosmology constraints resulting from those studies. We also present a One-Percent Survey conducted at the conclusion of SV covering 140 deg2 using the final target selection algorithms with exposures of a depth typical of the main survey. The SV indicates that DESI will be able to complete the full 14,000 deg2 program with spectroscopically confirmed targets from the MWS, BGS, LRG, ELG, and quasar programs with total sample sizes of 7.2, 13.8, 7.46, 15.7, and 2.87 million, respectively. These samples will allow exploration of the Milky Way halo, clustering on all scales, and BAO measurements with a statistical precision of 0.28% over the redshift interval z < 1.1, 0.39% over the redshift interval 1.1 < z < 1.9, and 0.46% over the redshift interval 1.9 < z < 3.5.

Published
2024

18. Broad Absorption Line Quasars in the Dark Energy Spectroscopic Instrument Early Data Release

Author

Filbert, S., Martini, P., Seebaluck, K., Ennesser, L., Alexander, D. M., Bault, A., Brodzeller, A., Herrera-Alcantar, H. K., Montero-Camacho, P., Pérez-Ràfols, I., Ramírez-Pérez, C., Ravoux, C., Tan, T., Aguilar, J., Ahlen, S., Bailey, S., Brooks, D., Claybaugh, T., Dawson, K., de la Macorra, A., Doel, P., Fanning, K., Font-Ribera, A., Forero-Romero, J. E., Gontcho, S. Gontcho A, Guy, J., Kirkby, D., Kremin, A., Magneville, C., Manera, M., Meisner, A., Miquel, R., Moustakas, J., Nie, J., Percival, W. J., Prada, F., Rezaie, M., Rossi, G., Sanchez, E., Schubnell, M., Seo, H., Tarlé, G., Weaver, B. A., and Zhou, Z.

Subjects
Astrophysics - Cosmology and Nongalactic Astrophysics
Abstract

Broad absorption line (BAL) quasars are characterized by gas clouds that absorb flux at the wavelength of common quasar spectral features, although blueshifted by velocities that can exceed 0.1c. BAL features are interesting as signatures of significant feedback, yet they can also compromise cosmological studies with quasars by distorting the shape of the most prominent quasar emission lines, impacting redshift accuracy and measurements of the matter density distribution traced by the Lyman-alpha forest. We present a catalog of BAL quasars discovered in the Dark Energy Spectroscopic Instrument (DESI) survey Early Data Release, which were observed as part of DESI Survey Validation, as well as the first two months of the main survey. We describe our method to automatically identify BAL quasars in DESI data, the quantities we measure for each BAL, and investigate the completeness and purity of this method with mock DESI observations. We mask the wavelengths of the BAL features and re-evaluate each BAL quasar redshift, finding new redshifts which are 243 km/s smaller on average for the BAL quasar sample. These new, more accurate redshifts are important to obtain the best measurements of quasar clustering, especially at small scales. Finally, we present some spectra of rarer classes of BALs that illustrate the potential of DESI data to identify such populations for further study.

Published
2023

19. 3D Correlations in the Lyman-$\alpha$ Forest from Early DESI Data

Author

Gordon, Calum, Cuceu, Andrei, Chaves-Montero, Jonás, Font-Ribera, Andreu, González-Morales, Alma Xochitl, Aguilar, J., Ahlen, S., Armengaud, E., Bailey, S., Bault, A., Brodzeller, A., Brooks, D., Claybaugh, T., de la Cruz, R., Dawson, K., Doel, P., Forero-Romero, J. E., Gontcho, S. Gontcho A, Guy, J., Herrera-Alcantar, H. K., Iršič, V., Karaçaylı, N. G., Kirkby, D., Landriau, M., Guillou, L. Le, Levi, M. E., de la Macorra, A., Manera, M., Martini, P., Meisner, A., Miquel, R., Montero-Camacho, P., Muñoz-Gutiérrez, A., Napolitano, L., Nie, J., Niz, G., Palanque-Delabrouille, N., Percival, W. J., Pieri, M., Poppett, C., Prada, F., Pérez-Ràfols, I., Ramírez-Pérez, C., Ravoux, C., Rezaie, M., Ross, A. J., Rossi, G., Sanchez, E., Schlegel, D., Schubnell, M., Seo, H., Sinigaglia, F., Tan, T., Tarlé, G., Walther, M., Weaver, B. A., Yèche, C., Zhou, Z., and Zou, H.

Subjects
Astrophysics - Cosmology and Nongalactic Astrophysics
Abstract

We present the first measurements of Lyman-$\alpha$ (Ly$\alpha$) forest correlations using early data from the Dark Energy Spectroscopic Instrument (DESI). We measure the auto-correlation of Ly$\alpha$ absorption using 88,509 quasars at $z>2$, and its cross-correlation with quasars using a further 147,899 tracer quasars at $z\gtrsim1.77$. Then, we fit these correlations using a 13-parameter model based on linear perturbation theory and find that it provides a good description of the data across a broad range of scales. We detect the BAO peak with a signal-to-noise ratio of $3.8\sigma$, and show that our measurements of the auto- and cross-correlations are fully-consistent with previous measurements by the Extended Baryon Oscillation Spectroscopic Survey (eBOSS). Even though we only use here a small fraction of the final DESI dataset, our uncertainties are only a factor of 1.7 larger than those from the final eBOSS measurement. We validate the existing analysis methods of Ly$\alpha$ correlations in preparation for making a robust measurement of the BAO scale with the first year of DESI data.

Published
2023

20. The Early Data Release of the Dark Energy Spectroscopic Instrument

Author

DESI Collaboration, Adame, A. G., Aguilar, J., Ahlen, S., Alam, S., Aldering, G., Alexander, D. M., Alfarsy, R., Prieto, C. Allende, Alvarez, M., Alves, O., Anand, A., Andrade-Oliveira, F., Armengaud, E., Asorey, J., Avila, S., Aviles, A., Bailey, S., Balaguera-Antolínez, A., Ballester, O., Baltay, C., Bault, A., Bautista, J., Behera, J., Beltran, S. F., BenZvi, S., Silva, L. Beraldo e, Bermejo-Climent, J. R., Berti, A., Besuner, R., Beutler, F., Bianchi, D., Blake, C., Blum, R., Bolton, A. S., Brieden, S., Brodzeller, A., Brooks, D., Brown, Z., Buckley-Geer, E., Burtin, E., Cabayol-Garcia, L., Cai, Z., Canning, R., Cardiel-Sas, L., Rosell, A. Carnero, Castander, F. J., Cervantes-Cota, J. L., Chabanier, S., Chaussidon, E., Chaves-Montero, J., Chen, S., Chen, X., Chuang, C., Claybaugh, T., Cole, S., Cooper, A. P., Cuceu, A., Davis, T. M., Dawson, K., de Belsunce, R., de la Cruz, R., de la Macorra, A., Della Costa, J., de Mattia, A., Demina, R., Demirbozan, U., DeRose, J., Dey, A., Dey, B., Dhungana, G., Ding, J., Ding, Z., Doel, P., Doshi, R., Douglass, K., Edge, A., Eftekharzadeh, S., Eisenstein, D. J., Elliott, A., Escoffier, S., Fagrelius, P., Fan, X., Fanning, K., Fawcett, V. A., Ferraro, S., Ereza, J., Flaugher, B., Font-Ribera, A., Forero-Sánchez, D., Forero-Romero, J. E., Frenk, C. S., Gänsicke, B. T., García, L. Á., García-Bellido, J., Garcia-Quintero, C., Garrison, L. H., Gil-Marín, H., Golden-Marx, J., Gontcho, S. Gontcho A, Gonzalez-Morales, A. X., Gonzalez-Perez, V., Gordon, C., Graur, O., Green, D., Gruen, D., Guy, J., Hadzhiyska, B., Hahn, C., Han, J. J., Hanif, M. M. S, Herrera-Alcantar, H. K., Honscheid, K., Hou, J., Howlett, C., Huterer, D., Iršič, V., Ishak, M., Jacques, A., Jana, A., Jiang, L., Jimenez, J., Jing, Y. P., Joudaki, S., Jullo, E., Juneau, S., Kizhuprakkat, N., Karaçaylı, N. G., Karim, T., Kehoe, R., Kent, S., Khederlarian, A., Kim, S., Kirkby, D., Kisner, T., Kitaura, F., Kneib, J., Koposov, S. E., Kovács, A., Kremin, A., Krolewski, A., L'Huillier, B., Lahav, O., Lambert, A., Lamman, C., Lan, T. -W., Landriau, M., Lang, D., Lange, J. U., Lasker, J., Leauthaud, A., Guillou, L. Le, Levi, M. E., Li, T. S., Linder, E., Lyons, A., Magneville, C., Manera, M., Manser, C. J., Margala, D., Martini, P., McDonald, P., Medina, G. E., Medina-Varela, L., Meisner, A., Mena-Fernández, J., Meneses-Rizo, J., Mezcua, M., Miquel, R., Montero-Camacho, P., Moon, J., Moore, S., Moustakas, J., Mueller, E., Mundet, J., Muñoz-Gutiérrez, A., Myers, A. D., Nadathur, S., Napolitano, L., Neveux, R., Newman, J. A., Nie, J., Nikutta, R., Niz, G., Norberg, P., Noriega, H. E., Paillas, E., Palanque-Delabrouille, N., Palmese, A., Zhiwei, P., Parkinson, D., Penmetsa, S., Percival, W. J., Pérez-Fernández, A., Pérez-Ràfols, I., Pieri, M., Poppett, C., Porredon, A., Pothier, S., Prada, F., Pucha, R., Raichoor, A., Ramírez-Pérez, C., Ramirez-Solano, S., Rashkovetskyi, M., Ravoux, C., Rocher, A., Rockosi, C., Ross, A. J., Rossi, G., Ruggeri, R., Ruhlmann-Kleider, V., Sabiu, C. G., Said, K., Saintonge, A., Samushia, L., Sanchez, E., Saulder, C., Schaan, E., Schlafly, E. F., Schlegel, D., Scholte, D., Schubnell, M., Seo, H., Shafieloo, A., Sharples, R., Sheu, W., Silber, J., Sinigaglia, F., Siudek, M., Slepian, Z., Smith, A., Soumagnac, M. T., Sprayberry, D., Stephey, L., Suárez-Pérez, J., Sun, Z., Tan, T., Tarlé, G., Tojeiro, R., Ureña-López, L. A., Vaisakh, R., Valcin, D., Valdes, F., Valluri, M., Vargas-Magaña, M., Variu, A., Verde, L., Walther, M., Wang, B., Wang, M. S., Weaver, B. A., Weaverdyck, N., Wechsler, R. H., White, M., Xie, Y., Yang, J., Yèche, C., Yu, J., Yuan, S., Zhang, H., Zhang, Z., Zhao, C., Zheng, Z., Zhou, R., Zhou, Z., Zou, H., Zou, S., and Zu, Y.

Subjects
Astrophysics - Cosmology and Nongalactic Astrophysics
Abstract

The Dark Energy Spectroscopic Instrument (DESI) completed its five-month Survey Validation in May 2021. Spectra of stellar and extragalactic targets from Survey Validation constitute the first major data sample from the DESI survey. This paper describes the public release of those spectra, the catalogs of derived properties, and the intermediate data products. In total, the public release includes good-quality spectral information from 466,447 objects targeted as part of the Milky Way Survey, 428,758 as part of the Bright Galaxy Survey, 227,318 as part of the Luminous Red Galaxy sample, 437,664 as part of the Emission Line Galaxy sample, and 76,079 as part of the Quasar sample. In addition, the release includes spectral information from 137,148 objects that expand the scope beyond the primary samples as part of a series of secondary programs. Here, we describe the spectral data, data quality, data products, Large-Scale Structure science catalogs, access to the data, and references that provide relevant background to using these spectra., Comment: 43 pages, 7 figures, 17 tables, accepted for publication in the Astronomical Journal

Published
2023
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21. Validation of the Scientific Program for the Dark Energy Spectroscopic Instrument

Author

DESI Collaboration, Adame, A. G., Aguilar, J., Ahlen, S., Alam, S., Aldering, G., Alexander, D. M., Alfarsy, R., Prieto, C. Allende, Alvarez, M., Alves, O., Anand, A., Andrade-Oliveira, F., Armengaud, E., Asorey, J., Avila, S., Aviles, A., Bailey, S., Balaguera-Antolínez, A., Ballester, O., Baltay, C., Bault, A., Bautista, J., Behera, J., Beltran, S. F., BenZvi, S., Silva, L. Beraldo e, Bermejo-Climent, J. R., Berti, A., Besuner, R., Beutler, F., Bianchi, D., Blake, C., Blum, R., Bolton, A. S., Brieden, S., Brodzeller, A., Brooks, D., Brown, Z., Buckley-Geer, E., Burtin, E., Cabayol-Garcia, L., Cai, Z., Canning, R., Cardiel-Sas, L., Rosell, A. Carnero, Castander, F. J., Cervantes-Cota, J. L., Chabanier, S., Chaussidon, E., Chaves-Montero, J., Chen, S., Chuang, C., Claybaugh, T., Cole, S., Cooper, A. P., Cuceu, A., Davis, T. M., Dawson, K., de Belsunce, R., de la Cruz, R., de la Macorra, A., de Mattia, A., Demina, R., Demirbozan, U., DeRose, J., Dey, A., Dey, B., Dhungana, G., Ding, J., Ding, Z., Doel, P., Doshi, R., Douglass, K., Edge, A., Eftekharzadeh, S., Eisenstein, D. J., Elliott, A., Escoffier, S., Fagrelius, P., Fan, X., Fanning, K., Fawcett, V. A., Ferraro, S., Ereza, J., Flaugher, B., Font-Ribera, A., Forero-Sánchez, D., Forero-Romero, J. E., Frenk, C. S., Gänsicke, B. T., García, L. Á., García-Bellido, J., Garcia-Quintero, C., Garrison, L. H., Gil-Marín, H., Golden-Marx, J., Gontcho, S. Gontcho A, Gonzalez-Morales, A. X., Gonzalez-Perez, V., Gordon, C., Graur, O., Green, D., Gruen, D., Guy, J., Hadzhiyska, B., Hahn, C., Han, J. J., Hanif, M. M. S, Herrera-Alcantar, H. K., Honscheid, K., Hou, J., Howlett, C., Huterer, D., Iršič, V., Ishak, M., Jana, A., Jiang, L., Jimenez, J., Jing, Y. P., Joudaki, S., Joyce, R., Jullo, E., Juneau, S., Kizhuprakkat, N., Karaçaylı, N. G., Karim, T., Kehoe, R., Kent, S., Khederlarian, A., Kim, S., Kirkby, D., Kisner, T., Kitaura, F., Kneib, J., Koposov, S. E., Kovács, A., Kremin, A., Krolewski, A., L'Huillier, B., Lahav, O., Lambert, A., Lamman, C., Lan, T. -W., Landriau, M., Lang, D., Lange, J. U., Lasker, J., Guillou, L. Le, Leauthaud, A., Levi, M. E., Li, T. S., Linder, E., Lyons, A., Magneville, C., Manera, M., Manser, C. J., Margala, D., Martini, P., McDonald, P., Medina, G. E., Medina-Varela, L., Meisner, A., Mena-Fernández, J., Meneses-Rizo, J., Mezcua, M., Miquel, R., Montero-Camacho, P., Moon, J., Moore, S., Moustakas, J., Mueller, E., Mundet, J., Muñoz-Gutiérrez, A., Myers, A. D., Nadathur, S., Napolitano, L., Neveux, R., Newman, J. A., Nie, J., Niz, G., Norberg, P., Noriega, H. E., Paillas, E., Palanque-Delabrouille, N., Palmese, A., Zhiwei, P., Parkinson, D., Penmetsa, S., Percival, W. J., Pérez-Fernández, A., Pérez-Ràfols, I., Pieri, M., Poppett, C., Porredon, A., Prada, F., Pucha, R., Raichoor, A., Ramírez-Pérez, C., Ramirez-Solano, S., Rashkovetskyi, M., Ravoux, C., Rocher, A., Rockosi, C., Ross, A. J., Rossi, G., Ruggeri, R., Ruhlmann-Kleider, V., Sabiu, C. G., Said, K., Saintonge, A., Samushia, L., Sanchez, E., Saulder, C., Schaan, E., Schlafly, E. F., Schlegel, D., Scholte, D., Schubnell, M., Seo, H., Shafieloo, A., Sharples, R., Sheu, W., Silber, J., Sinigaglia, F., Siudek, M., Slepian, Z., Smith, A., Sprayberry, D., Stephey, L., Suárez-Pérez, J., Sun, Z., Tan, T., Tarlé, G., Tojeiro, R., Ureña-López, L. A., Vaisakh, R., Valcin, D., Valdes, F., Valluri, M., Vargas-Magaña, M., Variu, A., Verde, L., Walther, M., Wang, B., Wang, M. S., Weaver, B. A., Weaverdyck, N., Wechsler, R. H., White, M., Xie, Y., Yang, J., Yèche, C., Yu, J., Yuan, S., Zhang, H., Zhang, Z., Zhao, C., Zheng, Z., Zhou, R., Zhou, Z., Zou, H., Zou, S., and Zu, Y.

Subjects
Astrophysics - Cosmology and Nongalactic Astrophysics
Abstract

The Dark Energy Spectroscopic Instrument (DESI) was designed to conduct a survey covering 14,000 deg$^2$ over five years to constrain the cosmic expansion history through precise measurements of Baryon Acoustic Oscillations (BAO). The scientific program for DESI was evaluated during a five month Survey Validation (SV) campaign before beginning full operations. This program produced deep spectra of tens of thousands of objects from each of the stellar (MWS), bright galaxy (BGS), luminous red galaxy (LRG), emission line galaxy (ELG), and quasar target classes. These SV spectra were used to optimize redshift distributions, characterize exposure times, determine calibration procedures, and assess observational overheads for the five-year program. In this paper, we present the final target selection algorithms, redshift distributions, and projected cosmology constraints resulting from those studies. We also present a `One-Percent survey' conducted at the conclusion of Survey Validation covering 140 deg$^2$ using the final target selection algorithms with exposures of a depth typical of the main survey. The Survey Validation indicates that DESI will be able to complete the full 14,000 deg$^2$ program with spectroscopically-confirmed targets from the MWS, BGS, LRG, ELG, and quasar programs with total sample sizes of 7.2, 13.8, 7.46, 15.7, and 2.87 million, respectively. These samples will allow exploration of the Milky Way halo, clustering on all scales, and BAO measurements with a statistical precision of 0.28% over the redshift interval $z<1.1$, 0.39% over the redshift interval $1.1

Published
2023
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22. Performance of the Quasar Spectral Templates for the Dark Energy Spectroscopic Instrument

Author

Brodzeller, Allyson, Dawson, Kyle, Bailey, Stephen, Yu, Jiaxi, Ross, A. J., Bault, A., Filbert, S., Aguilar, J., Ahlen, S., Alexander, David M., Armengaud, E., Berti, A., Brooks, D., Chaussidon, E., de la Macorra, A., Doel, P., Fanning, K., Fawcett, V. A., Font-Ribera, A., Gontcho, S. Gontcho A, Guy, J., Honscheid, K., Juneau, S., Kehoe, R., Kisner, T., Kremin, Anthony, Lan, Ting-Wen, Landriau, M., Levi, Michael E., Magneville, C., Martini, Paul, Meisner, Aaron M., Miquel, R., Moustakas, J., Palanque-Delabrouille, N., Percival, W. J., Prada, F., Ravoux, C., Rossi, Graziano, Saulder, C., Siudek, M., Tarlé, Gregory, Weaver, B. A., Youles, S., Zheng, Zheng, Zhou, Rongpu, and Zhou, Zhimin

Subjects
Astrophysics - Instrumentation and Methods for Astrophysics, Astrophysics - Cosmology and Nongalactic Astrophysics
Abstract

Millions of quasar spectra will be collected by the Dark Energy Spectroscopic Instrument (DESI), leading to a four-fold increase in the number of known quasars. High accuracy quasar classification is essential to tighten constraints on cosmological parameters measured at the highest redshifts DESI observes ($z>2.0$). We present the spectral templates for identification and redshift estimation of quasars in the DESI Year 1 data release. The quasar templates are comprised of two quasar eigenspectra sets, trained on spectra from the Sloan Digital Sky Survey. The sets are specialized to reconstruct quasar spectral variation observed over separate yet overlapping redshift ranges and, together, are capable of identifying DESI quasars from $0.05 < z <7.0$. The new quasar templates show significant improvement over the previous DESI quasar templates regarding catastrophic failure rates, redshift precision and accuracy, quasar completeness, and the contamination fraction in the final quasar sample., Comment: to be published in Astronomical Journal; 21 pages, 8 figures

Published
2023
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23. Improved Tomographic Binning of 3x2pt Lens Samples: Neural Network Classifiers and Optimal Bin Assignments

Author

Moskowitz, Irene, Gawiser, Eric, Bault, Abby, Broussard, Adam, Newman, Jeffrey A., Zuntz, Joe, and Collaboration, the LSST Dark Energy Science

Subjects
Astrophysics - Cosmology and Nongalactic Astrophysics
Abstract

Large imaging surveys, such as the Legacy Survey of Space and Time, rely on photometric redshifts and tomographic binning for 3x2pt analyses that combine galaxy clustering and weak lensing. In this paper, we propose a method for optimizing the tomographic binning choice for the lens sample of galaxies. We divide the CosmoDC2 and Buzzard simulated galaxy catalogs into a training set and an application set, where the training set is nonrepresentative in a realistic way, and then estimate photometric redshifts for the application sets. The galaxies are sorted into redshift bins covering equal intervals of redshift or comoving distance, or with an equal number of galaxies in each bin, and we consider a generalized extension of these approaches. We find that bins of equal comoving distance produce the highest dark energy figure of merit of the initial binning choices, but that the choice of bin edges can be further optimized. We then train a neural network classifier to identify galaxies that are either highly likely to have accurate photometric redshift estimates or highly likely to be sorted into the correct redshift bin. The neural network classifier is used to remove poor redshift estimates from the sample, and the results are compared to the case when none of the sample is removed. We find that the neural network classifiers are able to improve the figure of merit by ~13% and are able to recover ~25% of the loss in the figure of merit that occurs when a nonrepresentative training sample is used., Comment: 18 pages, 14 figures

Published
2022
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26. Overview of the Instrumentation for the Dark Energy Spectroscopic Instrument

Author

Abareshi, B., Aguilar, J., Ahlen, S., Alam, Shadab, Alexander, David M., Alfarsy, R., Allen, L., Prieto, C. Allende, Alves, O., Ameel, J., Armengaud, E., Asorey, J., Aviles, Alejandro, Bailey, S., Balaguera-Antolínez, A., Ballester, O., Baltay, C., Bault, A., Beltran, S. F., Benavides, B., BenZvi, S., Berti, A., Besuner, R., Beutler, Florian, Bianchi, D., Blake, C., Blanc, P., Blum, R., Bolton, A., Bose, S., Bramall, D., Brieden, S., Brodzeller, A., Brooks, D., Brownewell, C., Buckley-Geer, E., Cahn, R. N., Cai, Z., Canning, R., Rosell, A. Carnero, Carton, P., Casas, R., Castander, F. J., Cervantes-Cota, J. L., Chabanier, S., Chaussidon, E., Chuang, C., Circosta, C., Cole, S., Cooper, A. P., da Costa, L., Cousinou, M. -C., Cuceu, A., Davis, T. M., Dawson, K., de la Cruz-Noriega, R., de la Macorra, A., de Mattia, A., Della Costa, J., Demmer, P., Derwent, M., Dey, A., Dey, B., Dhungana, G., Ding, Z., Dobson, C., Doel, P., Donald-McCann, J., Donaldson, J., Douglass, K., Duan, Y., Dunlop, P., Edelstein, J., Eftekharzadeh, S., Eisenstein, D. J., Enriquez-Vargas, M., Escoffier, S., Evatt, M., Fagrelius, P., Fan, X., Fanning, K., Fawcett, V. A., Ferraro, S., Ereza, J., Flaugher, B., Font-Ribera, A., Forero-Romero, J. E., Frenk, C. S., Fromenteau, S., Gänsicke, B. T., Garcia-Quintero, C., Garrison, L., Gaztañaga, E., Gerardi, F., Gil-Marín, H., Gontcho, S. Gontcho A, Gonzalez-Morales, Alma X., Gonzalez-de-Rivera, G., Gonzalez-Perez, V., Gordon, C., Graur, O., Green, D., Grove, C., Gruen, D., Gutierrez, G., Guy, J., Hahn, C., Harris, S., Herrera, D., Herrera-Alcantar, Hiram K., Honscheid, K., Howlett, C., Huterer, D., Iršič, V., Ishak, M., Jelinsky, P., Jiang, L., Jimenez, J., Jing, Y. P., Joyce, R., Jullo, E., Juneau, S., Karaçaylı, N. G., Karamanis, M., Karcher, A., Karim, T., Kehoe, R., Kent, S., Kirkby, D., Kisner, T., Kitaura, F., Koposov, S. E., Kovács, A., Kremin, A., Krolewski, Alex, L'Huillier, B., Lahav, O., Lambert, A., Lamman, C., Lan, Ting-Wen, Landriau, M., Lane, S., Lang, D., Lange, J. U., Lasker, J., Guillou, L. Le, Leauthaud, A., Van Suu, A. Le, Levi, Michael E., Li, T. S., Magneville, C., Manera, M., Manser, Christopher J., Marshall, B., McCollam, W., McDonald, P., Meisner, Aaron M., Mezcua, J. Mena-Fernández M., Miller, T., Miquel, R., Montero-Camacho, P., Moon, J., Martini, J. Paul, Meneses-Rizo, J., Moustakas, J., Mueller, E., Muñoz-Gutiérrez, Andrea, Myers, Adam D., Nadathur, S., Najita, J., Napolitano, L., Neilsen, E., Newman, Jeffrey A., Nie, J. D., Ning, Y., Niz, G., Norberg, P., Noriega, Hernán E., O'Brien, T., Obuljen, A., Palanque-Delabrouille, N., Palmese, A., Zhiwei, P., Pappalardo, D., Peng, X., Percival, W. J., Perruchot, S., Pogge, R., Poppett, C., Porredon, A., Prada, F., Prochaska, J., Pucha, R., Pérez-Fernández, A., Pérez-Ráfols, I., Rabinowitz, D., Raichoor, A., Ramirez-Solano, S., Ramírez-Pérez, César, Ravoux, C., Reil, K., Rezaie, M., Rocher, A., Rockosi, C., Roe, N. A., Roodman, A., Ross, A. J., Rossi, G., Ruggeri, R., Ruhlmann-Kleider, V., Sabiu, C. G., Safonova, S., Said, K., Saintonge, A., Catonga, Javier Salas, Samushia, L., Sanchez, E., Saulder, C., Schaan, E., Schlafly, E., Schlegel, D., Schmoll, J., Scholte, D., Schubnell, M., Secroun, A., Seo, H., Serrano, S., Sharples, Ray M., Sholl, Michael J., Silber, Joseph Harry, Silva, D. R., Sirk, M., Siudek, M., Smith, A., Sprayberry, D., Staten, R., Stupak, B., Tan, T., Tarlé, Gregory, Tie, Suk Sien, Tojeiro, R., Ureña-López, L. A., Valdes, F., Valenzuela, O., Valluri, M., Vargas-Magaña, M., Verde, L., Walther, M., Wang, B., Wang, M. S., Weaver, B. A., Weaverdyck, C., Wechsler, R., Wilson, Michael J., Yang, J., Yu, Y., Yuan, S., Yèche, Christophe, Zhang, H., Zhang, K., Zhao, Cheng, Zhou, Rongpu, Zhou, Zhimin, Zou, H., Zou, J., Zou, S., and Zu, Y.

Subjects
Astrophysics - Instrumentation and Methods for Astrophysics, Astrophysics - Cosmology and Nongalactic Astrophysics
Abstract

The Dark Energy Spectroscopic Instrument (DESI) has embarked on an ambitious five-year survey to explore the nature of dark energy with spectroscopy of 40 million galaxies and quasars. DESI will determine precise redshifts and employ the Baryon Acoustic Oscillation method to measure distances from the nearby universe to z > 3.5, as well as measure the growth of structure and probe potential modifications to general relativity. In this paper we describe the significant instrumentation we developed for the DESI survey. The new instrumentation includes a wide-field, 3.2-deg diameter prime-focus corrector that focuses the light onto 5020 robotic fiber positioners on the 0.812 m diameter, aspheric focal surface. The positioners and their fibers are divided among ten wedge-shaped petals. Each petal is connected to one of ten spectrographs via a contiguous, high-efficiency, nearly 50 m fiber cable bundle. The ten spectrographs each use a pair of dichroics to split the light into three channels that together record the light from 360 - 980 nm with a resolution of 2000 to 5000. We describe the science requirements, technical requirements on the instrumentation, and management of the project. DESI was installed at the 4-m Mayall telescope at Kitt Peak, and we also describe the facility upgrades to prepare for DESI and the installation and functional verification process. DESI has achieved all of its performance goals, and the DESI survey began in May 2021. Some performance highlights include RMS positioner accuracy better than 0.1", SNR per \sqrt{\AA} > 0.5 for a z > 2 quasar with flux 0.28e-17 erg/s/cm^2/A at 380 nm in 4000s, and median SNR = 7 of the [OII] doublet at 8e-17 erg/s/cm^2 in a 1000s exposure for emission line galaxies at z = 1.4 - 1.6. We conclude with highlights from the on-sky validation and commissioning of the instrument, key successes, and lessons learned. (abridged), Comment: 78 pages, 32 figures, submitted to AJ

Published
2022
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27. Overview of the Instrumentation for the Dark Energy Spectroscopic Instrument

Author

Collaboration, DESI, Abareshi, B, Aguilar, J, Ahlen, S, Alam, Shadab, Alexander, David M, Alfarsy, R, Allen, L, Prieto, C Allende, Alves, O, Ameel, J, Armengaud, E, Asorey, J, Aviles, Alejandro, Bailey, S, Balaguera-Antolínez, A, Ballester, O, Baltay, C, Bault, A, Beltran, SF, Benavides, B, BenZvi, S, Berti, A, Besuner, R, Beutler, Florian, Bianchi, D, Blake, C, Blanc, P, Blum, R, Bolton, A, Bose, S, Bramall, D, Brieden, S, Brodzeller, A, Brooks, D, Brownewell, C, Buckley-Geer, E, Cahn, RN, Cai, Z, Canning, R, Capasso, R, Rosell, A Carnero, Carton, P, Casas, R, Castander, FJ, Cervantes-Cota, JL, Chabanier, S, Chaussidon, E, Chuang, C, Circosta, C, Cole, S, Cooper, AP, da Costa, L, Cousinou, M-C, Cuceu, A, Davis, TM, Dawson, K, de la Cruz-Noriega, R, de la Macorra, A, de Mattia, A, Della Costa, J, Demmer, P, Derwent, M, Dey, A, Dey, B, Dhungana, G, Ding, Z, Dobson, C, Doel, P, Donald-McCann, J, Donaldson, J, Douglass, K, Duan, Y, Dunlop, P, Edelstein, J, Eftekharzadeh, S, Eisenstein, DJ, Enriquez-Vargas, M, Escoffier, S, Evatt, M, Fagrelius, P, Fan, X, Fanning, K, Fawcett, VA, Ferraro, S, Ereza, J, Flaugher, B, Font-Ribera, A, Forero-Romero, JE, Frenk, CS, Fromenteau, S, Gänsicke, BT, Garcia-Quintero, C, Garrison, L, Gaztañaga, E, Gerardi, F, Gil-Marín, H, Gontcho, S Gontcho A, Gonzalez-Morales, Alma X, and Gonzalez-de-Rivera, G

Subjects
Astronomical and Space Sciences, Astronomy & Astrophysics
Abstract

The Dark Energy Spectroscopic Instrument (DESI) embarked on an ambitious 5 yr survey in 2021 May to explore the nature of dark energy with spectroscopic measurements of 40 million galaxies and quasars. DESI will determine precise redshifts and employ the baryon acoustic oscillation method to measure distances from the nearby universe to beyond redshift z > 3.5, and employ redshift space distortions to measure the growth of structure and probe potential modifications to general relativity. We describe the significant instrumentation we developed to conduct the DESI survey. This includes: a wide-field, 3.°2 diameter prime-focus corrector; a focal plane system with 5020 fiber positioners on the 0.812 m diameter, aspheric focal surface; 10 continuous, high-efficiency fiber cable bundles that connect the focal plane to the spectrographs; and 10 identical spectrographs. Each spectrograph employs a pair of dichroics to split the light into three channels that together record the light from 360-980 nm with a spectral resolution that ranges from 2000-5000. We describe the science requirements, their connection to the technical requirements, the management of the project, and interfaces between subsystems. DESI was installed at the 4 m Mayall Telescope at Kitt Peak National Observatory and has achieved all of its performance goals. Some performance highlights include an rms positioner accuracy of better than 0.″1 and a median signal-to-noise ratio of 7 of the [O ii] doublet at 8 × 10-17 erg s-1 cm-2 in 1000 s for galaxies at z = 1.4-1.6. We conclude with additional highlights from the on-sky validation and commissioning, key successes, and lessons learned.

Published
2022

28. Overview of the Instrumentation for the Dark Energy Spectroscopic Instrument

Author

Abareshi, B, Aguilar, J, Ahlen, S, Alam, Shadab, Alexander, David M, Alfarsy, R, Allen, L, Prieto, C Allende, Alves, O, Ameel, J, Armengaud, E, Asorey, J, Aviles, Alejandro, Bailey, S, Balaguera-Antolínez, A, Ballester, O, Baltay, C, Bault, A, Beltran, SF, Benavides, B, BenZvi, S, Berti, A, Besuner, R, Beutler, Florian, Bianchi, D, Blake, C, Blanc, P, Blum, R, Bolton, A, Bose, S, Bramall, D, Brieden, S, Brodzeller, A, Brooks, D, Brownewell, C, Buckley-Geer, E, Cahn, RN, Cai, Z, Canning, R, Rosell, A Carnero, Carton, P, Casas, R, Castander, FJ, Cervantes-Cota, JL, Chabanier, S, Chaussidon, E, Chuang, C, Circosta, C, Cole, S, Cooper, AP, Costa, L da, Cousinou, M-C, Cuceu, A, Davis, TM, Dawson, K, Cruz-Noriega, R de la, Macorra, A de la, Mattia, A de, Costa, J Della, Demmer, P, Derwent, M, Dey, A, Dey, B, Dhungana, G, Ding, Z, Dobson, C, Doel, P, Donald-McCann, J, Donaldson, J, Douglass, K, Duan, Y, Dunlop, P, Edelstein, J, Eftekharzadeh, S, Eisenstein, DJ, Enriquez-Vargas, M, Escoffier, S, Evatt, M, Fagrelius, P, Fan, X, Fanning, K, Fawcett, VA, Ferraro, S, Ereza, J, Flaugher, B, Font-Ribera, A, Forero-Romero, JE, Frenk, CS, Fromenteau, S, Gänsicke, BT, Garcia-Quintero, C, Garrison, L, Gaztañaga, E, Gerardi, F, Gil-Marín, H, Gontcho, S Gontcho A, Gonzalez-Morales, Alma X, Gonzalez-de-Rivera, G, Gonzalez-Perez, V, and Gordon, C

Subjects
astro-ph.IM, astro-ph.CO
Abstract

The Dark Energy Spectroscopic Instrument (DESI) has embarked on an ambitiousfive-year survey to explore the nature of dark energy with spectroscopy of 40million galaxies and quasars. DESI will determine precise redshifts and employthe Baryon Acoustic Oscillation method to measure distances from the nearbyuniverse to z > 3.5, as well as measure the growth of structure and probepotential modifications to general relativity. In this paper we describe thesignificant instrumentation we developed for the DESI survey. The newinstrumentation includes a wide-field, 3.2-deg diameter prime-focus correctorthat focuses the light onto 5020 robotic fiber positioners on the 0.812 mdiameter, aspheric focal surface. The positioners and their fibers are dividedamong ten wedge-shaped petals. Each petal is connected to one of tenspectrographs via a contiguous, high-efficiency, nearly 50 m fiber cablebundle. The ten spectrographs each use a pair of dichroics to split the lightinto three channels that together record the light from 360 - 980 nm with aresolution of 2000 to 5000. We describe the science requirements, technicalrequirements on the instrumentation, and management of the project. DESI wasinstalled at the 4-m Mayall telescope at Kitt Peak, and we also describe thefacility upgrades to prepare for DESI and the installation and functionalverification process. DESI has achieved all of its performance goals, and theDESI survey began in May 2021. Some performance highlights include RMSpositioner accuracy better than 0.1", SNR per \sqrt{\AA} > 0.5 for a z > 2quasar with flux 0.28e-17 erg/s/cm^2/A at 380 nm in 4000s, and median SNR = 7of the [OII] doublet at 8e-17 erg/s/cm^2 in a 1000s exposure for emission linegalaxies at z = 1.4 - 1.6. We conclude with highlights from the on-skyvalidation and commissioning of the instrument, key successes, and lessonslearned. (abridged)

Published
2022

29. The LSST-DESC 3x2pt Tomography Optimization Challenge

Author

Zuntz, Joe, Lanusse, François, Malz, Alex I., Wright, Angus H., Slosar, Anže, Abolfathi, Bela, Alonso, David, Bault, Abby, Bom, Clécio R., Brescia, Massimo, Broussard, Adam, Campagne, Jean-Eric, Cavuoti, Stefano, Cypriano, Eduardo S., Fraga, Bernardo M. O., Gawiser, Eric, Gonzalez, Elizabeth J., Green, Dylan, Hatfield, Peter, Iyer, Kartheik, Kirkby, David, Nicola, Andrina, Nourbakhsh, Erfan, Park, Andy, Teixeira, Gabriel, Heitmann, Katrin, Kovacs, Eve, and Mao, Yao-Yuan

Subjects
Astrophysics - Instrumentation and Methods for Astrophysics, Astrophysics - Cosmology and Nongalactic Astrophysics
Abstract

This paper presents the results of the Rubin Observatory Dark Energy Science Collaboration (DESC) 3x2pt tomography challenge, which served as a first step toward optimizing the tomographic binning strategy for the main DESC analysis. The task of choosing an optimal tomographic binning scheme for a photometric survey is made particularly delicate in the context of a metacalibrated lensing catalogue, as only the photometry from the bands included in the metacalibration process (usually riz and potentially g) can be used in sample definition. The goal of the challenge was to collect and compare bin assignment strategies under various metrics of a standard 3x2pt cosmology analysis in a highly idealized setting to establish a baseline for realistically complex follow-up studies; in this preliminary study, we used two sets of cosmological simulations of galaxy redshifts and photometry under a simple noise model neglecting photometric outliers and variation in observing conditions, and contributed algorithms were provided with a representative and complete training set. We review and evaluate the entries to the challenge, finding that even from this limited photometry information, multiple algorithms can separate tomographic bins reasonably well, reaching figures-of-merit scores close to the attainable maximum. We further find that adding the g band to riz photometry improves metric performance by ~15% and that the optimal bin assignment strategy depends strongly on the science case: which figure-of-merit is to be optimized, and which observables (clustering, lensing, or both) are included., Comment: 30 pages (incl. 12 in appendix), 12 figures. Version accepted for publication in the Open Journal of Astrophysics

Published
2021
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31. A dynamic and collaborative database for morphogeometric information of trilobites

Author

Fernanda Serra, Diego Balseiro, Claude Monnet, Enrique Randolfe, Arnaud Bignon, Juan J. Rustán, Valentin Bault, Diego F. Muñoz, N. Emilio Vaccari, Malena Martinetto, Catherine Crônier, and Beatriz G. Waisfeld

Subjects
Science
Abstract

Abstract Modern morphometric-based approaches provide valuable metrics to quantify and understand macroevolutionary and macroecological patterns and processes. Here we describe TriloMorph, an openly accessible database for morpho-geometric information of trilobites, together with a landmark acquisition protocol. In addition to morphological traits, the database contains contextual data on chronostratigraphic age, geographic location, taxonomic information and lithology of landmarked specimens. In this first version, the dataset has broad taxonomic and temporal coverage and comprises more than 55% of all trilobite genera and 85% of families recorded in the Paleobiology Database through the Devonian. We provide a release of geometric morphometric data of 277 specimens linked to published references. Additionally, we established a Github repository for constant input of morphometric data by multiple contributors and present R functions that help with data retrieval and analysis. This is the first attempt of an online, dynamic and collaborative morphometric repository. By bringing this information into a single open database we enhance the possibility of performing global palaeobiological research, providing a major complement to current occurrence-based databases.

Published
2023
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34. Variability in the analysis of a single neuroimaging dataset by many teams

Author

Botvinik-Nezer, Rotem, Holzmeister, Felix, Camerer, Colin F, Dreber, Anna, Huber, Juergen, Johannesson, Magnus, Kirchler, Michael, Iwanir, Roni, Mumford, Jeanette A, Adcock, R Alison, Avesani, Paolo, Baczkowski, Blazej M, Bajracharya, Aahana, Bakst, Leah, Ball, Sheryl, Barilari, Marco, Bault, Nadège, Beaton, Derek, Beitner, Julia, Benoit, Roland G, Berkers, Ruud MWJ, Bhanji, Jamil P, Biswal, Bharat B, Bobadilla-Suarez, Sebastian, Bortolini, Tiago, Bottenhorn, Katherine L, Bowring, Alexander, Braem, Senne, Brooks, Hayley R, Brudner, Emily G, Calderon, Cristian B, Camilleri, Julia A, Castrellon, Jaime J, Cecchetti, Luca, Cieslik, Edna C, Cole, Zachary J, Collignon, Olivier, Cox, Robert W, Cunningham, William A, Czoschke, Stefan, Dadi, Kamalaker, Davis, Charles P, Luca, Alberto De, Delgado, Mauricio R, Demetriou, Lysia, Dennison, Jeffrey B, Di, Xin, Dickie, Erin W, Dobryakova, Ekaterina, Donnat, Claire L, Dukart, Juergen, Duncan, Niall W, Durnez, Joke, Eed, Amr, Eickhoff, Simon B, Erhart, Andrew, Fontanesi, Laura, Fricke, G Matthew, Fu, Shiguang, Galván, Adriana, Gau, Remi, Genon, Sarah, Glatard, Tristan, Glerean, Enrico, Goeman, Jelle J, Golowin, Sergej AE, González-García, Carlos, Gorgolewski, Krzysztof J, Grady, Cheryl L, Green, Mikella A, Guassi Moreira, João F, Guest, Olivia, Hakimi, Shabnam, Hamilton, J Paul, Hancock, Roeland, Handjaras, Giacomo, Harry, Bronson B, Hawco, Colin, Herholz, Peer, Herman, Gabrielle, Heunis, Stephan, Hoffstaedter, Felix, Hogeveen, Jeremy, Holmes, Susan, Hu, Chuan-Peng, Huettel, Scott A, Hughes, Matthew E, Iacovella, Vittorio, Iordan, Alexandru D, Isager, Peder M, Isik, Ayse I, Jahn, Andrew, Johnson, Matthew R, Johnstone, Tom, Joseph, Michael JE, Juliano, Anthony C, Kable, Joseph W, Kassinopoulos, Michalis, Koba, Cemal, and Kong, Xiang-Zhen

Subjects
Generic health relevance, Brain, Data Analysis, Data Science, Datasets as Topic, Female, Functional Neuroimaging, Humans, Logistic Models, Magnetic Resonance Imaging, Male, Meta-Analysis as Topic, Models, Neurological, Reproducibility of Results, Research Personnel, Software, General Science & Technology
Abstract

Data analysis workflows in many scientific domains have become increasingly complex and flexible. Here we assess the effect of this flexibility on the results of functional magnetic resonance imaging by asking 70 independent teams to analyse the same dataset, testing the same 9 ex-ante hypotheses1. The flexibility of analytical approaches is exemplified by the fact that no two teams chose identical workflows to analyse the data. This flexibility resulted in sizeable variation in the results of hypothesis tests, even for teams whose statistical maps were highly correlated at intermediate stages of the analysis pipeline. Variation in reported results was related to several aspects of analysis methodology. Notably, a meta-analytical approach that aggregated information across teams yielded a significant consensus in activated regions. Furthermore, prediction markets of researchers in the field revealed an overestimation of the likelihood of significant findings, even by researchers with direct knowledge of the dataset2-5. Our findings show that analytical flexibility can have substantial effects on scientific conclusions, and identify factors that may be related to variability in the analysis of functional magnetic resonance imaging. The results emphasize the importance of validating and sharing complex analysis workflows, and demonstrate the need for performing and reporting multiple analyses of the same data. Potential approaches that could be used to mitigate issues related to analytical variability are discussed.

Published
2020

35. Advancing Dark Energy Studies with DESI: Innovations in Instrumentation and Lyman-alpha Forest Cosmology

Author

Bault, Abigail

Subjects
Physics, Astronomy, Astrophysics
Abstract

One of the most compelling challenges in cosmology is understanding the nature of dark energy and how it affects the expansion of the universe. The Dark Energy Spectroscopic Instrument (DESI) is attempting to improve our understanding by using baryon acoustic oscillations (BAO) to study the expansion history of the universe. In Chapter 1 I provide a brief introduction to the expansion history of the universe as well as the probes of large scale structure. In Chapter 2 I provide an in depth description of the DESI instrument, focal plane, and main survey. This thesis consists of two main projects focused on improving the DESI focal plane and analyses using quasars and the Lyman-alpha forest. The first project, discussed in Chapter 3, focuses on improvements to the DESI focal plane. The focal plane uses 5,000 robotic fiber positioners, approximately 12% of which are unusable due to poor performance. Roughly half display linear phi behavior. This number is increasing at a rate of approximately 1 new positioner per week. If enough positioners become unusable, the main survey (and potential future DESI-ext and DESI-2 surveys) may not be able to finish on time. Many different mitigation strategies were studied, but I found that the best performance came by increasing the motor speed and by applying a scale factor correction. Each move also follows a new move strategy consisting of a back and forth move. Move tests were performed on the DESI focal plane in 2023 and in March and July of 2024. The July tests showed that 228 positioners could be recovered and returned to night operations. This is roughly 72% of the linear phi positioners. The second project, discussed in Chapter 4, focuses on how quasar redshift errors impact the correlation functions used in the Lyman-alpha forest analyses. We measure systematic quasar redshift errors as an offset in the Lyman-alpha forest-quasar cross-correlation. Using data from the DESI Early Data Release (EDR) I found evidence for a redshift-dependent bias causing quasar redshifts to be underestimated with increasing redshift. This bias stems from the improper modeling of the Lyman-alpha optical depth in the high redshift quasar templates used for redshift estimation. New templates were derived for the year 1 quasar sample. The analysis was repeated and I found that the bias resolved and is now consistent with zero. The new templates were used to provide redshifts for the DESI Year 1 quasar sample and will be used for future data releases as well.

Published
2024

38. Validation of the Scientific Program for the Dark Energy Spectroscopic Instrument

Author

DESI Collaboration, A. G. Adame, J. Aguilar, S. Ahlen, S. Alam, G. Aldering, D. M. Alexander, R. Alfarsy, C. Allende Prieto, M. Alvarez, O. Alves, A. Anand, F. Andrade-Oliveira, E. Armengaud, J. Asorey, S. Avila, A. Aviles, S. Bailey, A. Balaguera-Antolínez, O. Ballester, C. Baltay, A. Bault, J. Bautista, J. Behera, S. F. Beltran, S. BenZvi, L. Beraldo e Silva, J. R. Bermejo-Climent, A. Berti, R. Besuner, F. Beutler, D. Bianchi, C. Blake, R. Blum, A. S. Bolton, S. Brieden, A. Brodzeller, D. Brooks, Z. Brown, E. Buckley-Geer, E. Burtin, L. Cabayol-Garcia, Z. Cai, R. Canning, L. Cardiel-Sas, A. Carnero Rosell, F. J. Castander, J. L. Cervantes-Cota, S. Chabanier, E. Chaussidon, J. Chaves-Montero, S. Chen, X. Chen, C. Chuang, T. Claybaugh, S. Cole, A. P. Cooper, A. Cuceu, T. M. Davis, K. Dawson, R. de Belsunce, R. de la Cruz, A. de la Macorra, A. de Mattia, R. Demina, U. Demirbozan, J. DeRose, A. Dey, B. Dey, G. Dhungana, J. Ding, Z. Ding, P. Doel, R. Doshi, K. Douglass, A. Edge, S. Eftekharzadeh, D. J. Eisenstein, A. Elliott, S. Escoffier, P. Fagrelius, X. Fan, K. Fanning, V. A. Fawcett, S. Ferraro, J. Ereza, B. Flaugher, A. Font-Ribera, D. Forero-Sánchez, J. E. Forero-Romero, C. S. Frenk, B. T. Gänsicke, L. Á. García, J. García-Bellido, C. Garcia-Quintero, L. H. Garrison, H. Gil-Marín, J. Golden-Marx, S. Gontcho A Gontcho, A. X. Gonzalez-Morales, V. Gonzalez-Perez, C. Gordon, O. Graur, D. Green, D. Gruen, J. Guy, B. Hadzhiyska, C. Hahn, J. J. Han, M. M. S Hanif, H. K. Herrera-Alcantar, K. Honscheid, J. Hou, C. Howlett, D. Huterer, V. Iršič, M. Ishak, A. Jana, L. Jiang, J. Jimenez, Y. P. Jing, S. Joudaki, E. Jullo, R. Joyce, S. Juneau, N. Kizhuprakkat, N. G. Karaçaylı, T. Karim, R. Kehoe, S. Kent, A. Khederlarian, S. Kim, D. Kirkby, T. Kisner, F. Kitaura, J. Kneib, S. E. Koposov, A. Kovács, A. Kremin, A. Krolewski, B. L’Huillier, O. Lahav, A. Lambert, C. Lamman, T.-W. Lan, M. Landriau, D. Lang, J. U. Lange, J. Lasker, L. Le Guillou, A. Leauthaud, M. E. Levi, T. S. Li, E. Linder, A. Lyons, C. Magneville, M. Manera, C. J. Manser, D. Margala, P. Martini, P. McDonald, G. E. Medina, L. Medina-Varela, A. Meisner, J. Mena-Fernández, J. Meneses-Rizo, M. Mezcua, R. Miquel, P. Montero-Camacho, J. Moon, S. Moore, J. Moustakas, E. Mueller, J. Mundet, A. Muñoz-Gutiérrez, A. D. Myers, S. Nadathur, L. Napolitano, R. Neveux, J. A. Newman, J. Nie, G. Niz, P. Norberg, H. E. Noriega, E. Paillas, N. Palanque-Delabrouille, A. Palmese, P. Zhiwei, D. Parkinson, S. Penmetsa, W. J. Percival, A. Pérez-Fernández, I. Pérez-Ràfols, M. Pieri, C. Poppett, A. Porredon, F. Prada, R. Pucha, A. Raichoor, C. Ramírez-Pérez, S. Ramirez-Solano, M. Rashkovetskyi, C. Ravoux, A. Rocher, C. Rockosi, A. J. Ross, G. Rossi, R. Ruggeri, V. Ruhlmann-Kleider, C. G. Sabiu, K. Said, A. Saintonge, L. Samushia, E. Sanchez, C. Saulder, E. Schaan, E. F. Schlafly, D. Schlegel, D. Scholte, M. Schubnell, H. Seo, A. Shafieloo, R. Sharples, W. Sheu, J. Silber, F. Sinigaglia, M. Siudek, Z. Slepian, A. Smith, D. Sprayberry, L. Stephey, J. Suárez-Pérez, Z. Sun, T. Tan, G. Tarlé, R. Tojeiro, L. A. Ureña-López, R. Vaisakh, D. Valcin, F. Valdes, M. Valluri, M. Vargas-Magaña, A. Variu, L. Verde, M. Walther, B. Wang, M. S. Wang, B. A. Weaver, N. Weaverdyck, R. H. Wechsler, M. White, Y. Xie, J. Yang, C. Yèche, J. Yu, S. Yuan, H. Zhang, Z. Zhang, C. Zhao, Z. Zheng, R. Zhou, Z. Zhou, H. Zou, S. Zou, and Y. Zu

Subjects
Cosmology, Redshift surveys, Astronomy, QB1-991
Abstract

The Dark Energy Spectroscopic Instrument (DESI) was designed to conduct a survey covering 14,000 deg ^2 over 5 yr to constrain the cosmic expansion history through precise measurements of baryon acoustic oscillations (BAO). The scientific program for DESI was evaluated during a 5 month survey validation (SV) campaign before beginning full operations. This program produced deep spectra of tens of thousands of objects from each of the stellar Milky Way Survey (MWS), Bright Galaxy Survey (BGS), luminous red galaxy (LRG), emission line galaxy (ELG), and quasar target classes. These SV spectra were used to optimize redshift distributions, characterize exposure times, determine calibration procedures, and assess observational overheads for the 5 yr program. In this paper, we present the final target selection algorithms, redshift distributions, and projected cosmology constraints resulting from those studies. We also present a One-Percent Survey conducted at the conclusion of SV covering 140 deg ^2 using the final target selection algorithms with exposures of a depth typical of the main survey. The SV indicates that DESI will be able to complete the full 14,000 deg ^2 program with spectroscopically confirmed targets from the MWS, BGS, LRG, ELG, and quasar programs with total sample sizes of 7.2, 13.8, 7.46, 15.7, and 2.87 million, respectively. These samples will allow exploration of the Milky Way halo, clustering on all scales, and BAO measurements with a statistical precision of 0.28% over the redshift interval z < 1.1, 0.39% over the redshift interval 1.1 < z < 1.9, and 0.46% over the redshift interval 1.9 < z < 3.5.

Published
2024
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39. Measuring Fiber Positioning Accuracy and Throughput with Fiber Dithering for the Dark Energy Spectroscopic Instrument

Author

E. F. Schlafly, D. Schlegel, S. BenZvi, A. Raichoor, J. E. Forero-Romero, J. Aguilar, S. Ahlen, S. Bailey, A. Bault, D. Brooks, T. Claybaugh, K. Dawson, A. de la Macorra, Arjun Dey, P. Doel, E. Gaztañaga, S. Gontcho A Gontcho, J. Guy, C. Hahn, K. Honscheid, J. Jimenez, S. Kent, D. Kirkby, T. Kisner, A. Kremin, A. Lambert, M. Landriau, M. E. Levi, M. Manera, P. Martini, A. Meisner, R. Miquel, J. Moustakas, A. D. Myers, J. Nie, N. Palanque-Delabrouille, W. J. Percival, C. Poppett, F. Prada, D. Rabinowitz, M. Rezaie, G. Rossi, E. Sanchez, M. Schubnell, R. Sharples, J. Silber, G. Tarlé, B. A. Weaver, Z. Zhou, H. Zou, and DESI Collaboration

Subjects
Spectroscopy, Astronomy, QB1-991
Abstract

Highly multiplexed, fiber-fed spectroscopy is enabling surveys of millions of stars and galaxies. The performance of these surveys depends on accurately positioning fibers in the focal plane to capture target light. We describe a technique to measure the positioning accuracy of fibers by dithering fibers slightly around their ideal locations. This approach also enables measurement of the total system throughput and point-spread function delivered to the focal plane. We then apply this technique to observations from the Dark Energy Survey Instrument (DESI), and demonstrate that DESI positions fibers to within 0.″08 of their targets (5% of a fiber diameter) and achieves a system throughput within about 7% of expectations.

Published
2024
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40. Overview of the Fiber System for the Dark Energy Spectroscopic Instrument

Author

Claire Poppett, Luke Tyas, J. Aguilar, Christopher Bebek, D. Bramall, T. Claybaugh, J. Edelstein, P. Fagrelius, H. Heetderks, P. Jelinsky, S. Jelinsky, Robin Lafever, A. Lambert, M. Lampton, Michael E. Levi, P. Martini, C. Rockosi, J. Schmoll, Ray M. Sharples, Martin Sirk, Edward Wishnow, Jiaxi Yu, S. Ahlen, A. Bault, S. BenZvi, D. Brooks, S. Cole, A. de la Macorra, Arjun Dey, P. Doel, K. Fanning, A. Font-Ribera, J. E. Forero-Romero, E. Gaztañaga, S. Gontcho A Gontcho, A. X. Gonzalez-Morales, C. Hahn, K. Honscheid, J. Jimenez, S. Juneau, D. Kirkby, A. Kremin, M. Landriau, L. Le Guillou, M. Manera, A. Meisner, R. Miquel, J. Moustakas, E. Mueller, A. Muñoz-Gutiérrez, A. D. Myers, J. Nie, G. Niz, N. Palanque-Delabrouille, W. J. Percival, F. Prada, D. Rabinowitz, M. Rezaie, G. Rossi, E. Sanchez, Edward F. Schlafly, D. Schlegel, M. Schubnell, H. Seo, D. Sprayberry, G. Tarlé, M. Vargas-Magaña, B. A. Weaver, and R. Zhou

Subjects
Cosmological evolution, Astronomical instrumentation, Galaxy spectroscopy, Astronomy, QB1-991
Abstract

The Dark Energy Spectroscopic Instrument (DESI) is a revolutionary instrument designed for precise measurements of cosmic distances and the investigation of dark energy. DESI utilizes 5000 optical fibers to simultaneously measure the spectra of distant objects and aims to measure 40 million galaxies and quasars in a 5 yr survey. One of the critical challenges to DESI’s success was ensuring that the fiber system was not only highly efficient but also delivered a highly stable beam enabling more reliable sky subtraction for measurements of faint objects. We achieved this stability by minimizing the stress on the fiber system during the manufacture and operation of the telescope and fiber positioning robots. We installed the DESI fiber system on the 4 m Mayall telescope with ≥99% of fibers intact, and the instrument has delivered superb optical performance throughout the initial years of the DESI survey, including ≥90% average throughput when injected with a focal ratio of ∼ f /3.9 as delivered by the primary focus corrector, excluding fiber absorption losses. The design of DESI required multiple innovations to achieve these requirements, such as cleaved fibers bonded with a UV-curing epoxy to glass ferrules in the focal plane and fusion splicing instead of physical connectors. In this paper, we describe the development, delivery, and installation of the fiber system, the innovations that made the state-of-the-art performance possible, and the key lessons learned that could benefit future projects.

Published
2024
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43. Variability in the analysis of a single neuroimaging dataset by many teams

Author

Botvinik-Nezer, R., Holzmeister, F., Camerer, C. F., Dreber, A., Huber, J., Johannesson, M., Kirchler, M., Iwanir, R., Mumford, J. A., Adcock, R. A., Avesani, P., Baczkowski, B. M., Bajracharya, A., Bakst, L., Ball, S., Barilari, M., Bault, N., Beaton, D., Beitner, J., Benoit, R. G., Berkers, R. M. W. J., Bhanji, J. P., Biswal, B. B., Bobadilla-Suarez, S., Bortolini, T., Bottenhorn, K. L., Bowring, A., Braem, S., Brooks, H. R., Brudner, E. G., Calderon, C. B., Camilleri, J. A., Castrellon, J. J., Cecchetti, L., Cieslik, E. C., Cole, Z. J., Collignon, O., Cox, R. W., Cunningham, W. A., Czoschke, S., Dadi, K., Davis, C. P., Luca, A. D., Delgado, M. R., Demetriou, L., Dennison, J. B., Di, X., Dickie, E. W., Dobryakova, E., Donnat, C. L., Dukart, J., Duncan, N. W., Durnez, J., Eed, A., Eickhoff, S. B., Erhart, A., Fontanesi, L., Fricke, G. M., Fu, S., Galván, A., Gau, R., Genon, S., Glatard, T., Glerean, E., Goeman, J. J., Golowin, S. A. E., González-García, C., Gorgolewski, K. J., Grady, C. L., Green, M. A., Guassi Moreira, J. F., Guest, O., Hakimi, S., Hamilton, J. P., Hancock, R., Handjaras, G., Harry, B.B., Hawco, C., Herholz, P., Herman, G., Heunis, S., Hoffstaedter, F., Hogeveen, J., Holmes, S., Hu, C. P., Huettel, S. A., Hughes, M. E., Iacovella, V., Iordan, A. D., Isager, P. M., Isik, A. I., Jahn, Andrew, Johnson, Matthew R., Johnstone, Tom, Joseph, Michael J. E., Juliano, Anthony C., Kable, Joseph W., Kassinopoulos, Michalis, Koba, Cemal, Kong, Xiang-Zhen, Koscik, Timothy R., Kucukboyaci, Nuri Erkut, Kuhl, Brice A., Kupek, Sebastian, Laird, Angela R., Lamm, Claus, Langner, Robert, Lauharatanahirun, Nina, Lee, Hongmi, Lee, Sangil, Leemans, Alexander, Leo, Andrea, Lesage, Elise, Li, Flora, Li, Monica Y. C., Lim, Cheng Phui, Lintz, Evan N., Liphardt, Schuyler W., Losecaat Vermeer, Annabel B., Love, Bradley C., Mack, Michael L., Malpica, Norberto, Marins, Theo, Maumet, Camille, McDonald, Kelsey, McGuire, Joseph T., Méndez Leal, Adriana S., Meyer, Benjamin, Meyer, Kristin N., Mihai, Glad, Mitsis, Georgios D., Moll, Jorge, Nielson, Dylan M., Nilsonne, Gustav, Notter, Michael P., Olivetti, Emanuele, Onicas, Adrian I., Papale, Paolo, Patil, Kaustubh R., Peelle, Jonathan E., Pérez, Alexandre, Pischedda, Doris, Poline, Jean-Baptiste, Prystauka,Yanina, Ray, Shruti, Reuter-Lorenz, Patricia A., Reynolds, Richard C., Ricciardi, Emiliano, Rieck, Jenny R., Rodriguez-Thompson, Anais M., Romyn, Anthony, Salo, Taylor, Samanez-Larkin, Gregory R., Sanz-Morales, Emilio, Schlichting, Margaret L., Schultz, Douglas H., Shen, Qiang, Sheridan, Margaret A., Silvers, Jennifer A., Skagerlund, Kenny, Smith, Alec, Smith, David V., Sokol-Hessner, Peter, Steinkamp, Simon R., Tashjian, Sarah M., Thirion, Bertrand, Thorp, John N., Tinghög, Gustav, Tisdall, Loreen, Tompson, Steven H., Toro-Serey, Claudio, Torre Tresols, Juan Jesus, Tozzi, Leonardo, Truong, Vuong, Turella, Luca, van ‘t Veer, Anna E., Verguts, Tom, Vettel, Jean M., Vijayarajah, Sagana, Vo, Khoi, Wall, Matthew B., Weeda, Wouter D., Weis, Susanne, White, David J., Wisniewski, David, Xifra-Porxas, Alba, Yearling, Emily A., Yoon, Sangsuk, Yuan, Rui, Yuen, Kenneth S. L., Lei Zhang, Zhang, Xu, Zosky, Joshua E., Thomas E. Nichols, Poldrack, Rusell A., Schonberg, Tom, Melero Carrasco, Helena, Botvinik-Nezer, R., Holzmeister, F., Camerer, C. F., Dreber, A., Huber, J., Johannesson, M., Kirchler, M., Iwanir, R., Mumford, J. A., Adcock, R. A., Avesani, P., Baczkowski, B. M., Bajracharya, A., Bakst, L., Ball, S., Barilari, M., Bault, N., Beaton, D., Beitner, J., Benoit, R. G., Berkers, R. M. W. J., Bhanji, J. P., Biswal, B. B., Bobadilla-Suarez, S., Bortolini, T., Bottenhorn, K. L., Bowring, A., Braem, S., Brooks, H. R., Brudner, E. G., Calderon, C. B., Camilleri, J. A., Castrellon, J. J., Cecchetti, L., Cieslik, E. C., Cole, Z. J., Collignon, O., Cox, R. W., Cunningham, W. A., Czoschke, S., Dadi, K., Davis, C. P., Luca, A. D., Delgado, M. R., Demetriou, L., Dennison, J. B., Di, X., Dickie, E. W., Dobryakova, E., Donnat, C. L., Dukart, J., Duncan, N. W., Durnez, J., Eed, A., Eickhoff, S. B., Erhart, A., Fontanesi, L., Fricke, G. M., Fu, S., Galván, A., Gau, R., Genon, S., Glatard, T., Glerean, E., Goeman, J. J., Golowin, S. A. E., González-García, C., Gorgolewski, K. J., Grady, C. L., Green, M. A., Guassi Moreira, J. F., Guest, O., Hakimi, S., Hamilton, J. P., Hancock, R., Handjaras, G., Harry, B.B., Hawco, C., Herholz, P., Herman, G., Heunis, S., Hoffstaedter, F., Hogeveen, J., Holmes, S., Hu, C. P., Huettel, S. A., Hughes, M. E., Iacovella, V., Iordan, A. D., Isager, P. M., Isik, A. I., Jahn, Andrew, Johnson, Matthew R., Johnstone, Tom, Joseph, Michael J. E., Juliano, Anthony C., Kable, Joseph W., Kassinopoulos, Michalis, Koba, Cemal, Kong, Xiang-Zhen, Koscik, Timothy R., Kucukboyaci, Nuri Erkut, Kuhl, Brice A., Kupek, Sebastian, Laird, Angela R., Lamm, Claus, Langner, Robert, Lauharatanahirun, Nina, Lee, Hongmi, Lee, Sangil, Leemans, Alexander, Leo, Andrea, Lesage, Elise, Li, Flora, Li, Monica Y. C., Lim, Cheng Phui, Lintz, Evan N., Liphardt, Schuyler W., Losecaat Vermeer, Annabel B., Love, Bradley C., Mack, Michael L., Malpica, Norberto, Marins, Theo, Maumet, Camille, McDonald, Kelsey, McGuire, Joseph T., Méndez Leal, Adriana S., Meyer, Benjamin, Meyer, Kristin N., Mihai, Glad, Mitsis, Georgios D., Moll, Jorge, Nielson, Dylan M., Nilsonne, Gustav, Notter, Michael P., Olivetti, Emanuele, Onicas, Adrian I., Papale, Paolo, Patil, Kaustubh R., Peelle, Jonathan E., Pérez, Alexandre, Pischedda, Doris, Poline, Jean-Baptiste, Prystauka,Yanina, Ray, Shruti, Reuter-Lorenz, Patricia A., Reynolds, Richard C., Ricciardi, Emiliano, Rieck, Jenny R., Rodriguez-Thompson, Anais M., Romyn, Anthony, Salo, Taylor, Samanez-Larkin, Gregory R., Sanz-Morales, Emilio, Schlichting, Margaret L., Schultz, Douglas H., Shen, Qiang, Sheridan, Margaret A., Silvers, Jennifer A., Skagerlund, Kenny, Smith, Alec, Smith, David V., Sokol-Hessner, Peter, Steinkamp, Simon R., Tashjian, Sarah M., Thirion, Bertrand, Thorp, John N., Tinghög, Gustav, Tisdall, Loreen, Tompson, Steven H., Toro-Serey, Claudio, Torre Tresols, Juan Jesus, Tozzi, Leonardo, Truong, Vuong, Turella, Luca, van ‘t Veer, Anna E., Verguts, Tom, Vettel, Jean M., Vijayarajah, Sagana, Vo, Khoi, Wall, Matthew B., Weeda, Wouter D., Weis, Susanne, White, David J., Wisniewski, David, Xifra-Porxas, Alba, Yearling, Emily A., Yoon, Sangsuk, Yuan, Rui, Yuen, Kenneth S. L., Lei Zhang, Zhang, Xu, Zosky, Joshua E., Thomas E. Nichols, Poldrack, Rusell A., Schonberg, Tom, and Melero Carrasco, Helena

Abstract

Data analysis workflows in many scientific domains have become increasingly complex and flexible. Here we assess the effect of this flexibility on the results of functional magnetic resonance imaging by asking 70 independent teams to analyse the same dataset, testing the same 9 ex-ante hypotheses1. The flexibility of analytical approaches is exemplified by the fact that no two teams chose identical workflows to analyse the data. This flexibility resulted in sizeable variation in the results of hypothesis tests, even for teams whose statistical maps were highly correlated at intermediate stages of the analysis pipeline. Variation in reported results was related to several aspects of analysis methodology. Notably, a meta-analytical approach that aggregated information across teams yielded a significant consensus in activated regions. Furthermore, prediction markets of researchers in the field revealed an overestimation of the likelihood of significant findings, even by researchers with direct knowledge of the dataset2–5. Our findings show that analytical flexibility can have substantial effects on scientific conclusions, and identify factors that may be related to variability in the analysis of functional magnetic resonance imaging. The results emphasize the importance of validating and sharing complex analysis workflows, and demonstrate the need for performing and reporting multiple analyses of the same data. Potential approaches that could be used to mitigate issues related to analytical variability are discussed., Depto. de Psicobiología y Metodología en Ciencias del Comportamiento, Fac. de Psicología, TRUE, pub

Published
2024

46. Biometric Parameters

Author

Levaillant, Jean-Marc, Bault, Jean-Philippe, Benoit, Bernard, Couly, Gérard, Levaillant, Jean-Marc, Bault, Jean-Philippe, Benoit, Bernard, and Couly, Gérard

Published
2017
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47. The Eye

Author

Levaillant, Jean-Marc, Bault, Jean-Philippe, Benoit, Bernard, Couly, Gérard, Levaillant, Jean-Marc, Bault, Jean-Philippe, Benoit, Bernard, and Couly, Gérard

Published
2017
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48. Facial Tumors

Author

Levaillant, Jean-Marc, Bault, Jean-Philippe, Benoit, Bernard, Couly, Gérard, Levaillant, Jean-Marc, Bault, Jean-Philippe, Benoit, Bernard, and Couly, Gérard

Published
2017
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49. Dysmorphism

Author

Levaillant, Jean-Marc, Bault, Jean-Philippe, Benoit, Bernard, Couly, Gérard, Levaillant, Jean-Marc, Bault, Jean-Philippe, Benoit, Bernard, and Couly, Gérard

Published
2017
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50. Clefts and Pierre-Robin Syndrome

Author

Levaillant, Jean-Marc, Bault, Jean-Philippe, Benoit, Bernard, Couly, Gérard, Levaillant, Jean-Marc, Bault, Jean-Philippe, Benoit, Bernard, and Couly, Gérard

Published
2017
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