Alignments between Galaxies and the Cosmic Web at z ∼ 1–2 in the IllustrisTNG Simulations
Galaxy formation theories predict that galaxy shapes and angular momenta have nonrandom alignments with the cosmic web. This leads to so-called intrinsic alignment between pairs of galaxies, which is important to quantify as a nuisance parameter for weak lensing. We study galaxy–cosmic web alignment...
| Main Authors: | , , , , , |
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| Format: | Article |
| Language: | English |
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IOP Publishing
2023-01-01
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| Series: | The Astrophysical Journal |
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| Online Access: | https://doi.org/10.3847/1538-4357/ace695 |
| _version_ | 1797694387329695744 |
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| author | Benjamin Zhang Khee-Gan Lee Alex Krolewski Jingjing Shi Benjamin Horowitz Robin Kooistra |
| author_facet | Benjamin Zhang Khee-Gan Lee Alex Krolewski Jingjing Shi Benjamin Horowitz Robin Kooistra |
| author_sort | Benjamin Zhang |
| collection | DOAJ |
| description | Galaxy formation theories predict that galaxy shapes and angular momenta have nonrandom alignments with the cosmic web. This leads to so-called intrinsic alignment between pairs of galaxies, which is important to quantify as a nuisance parameter for weak lensing. We study galaxy–cosmic web alignment in the IllustrisTNG suite of hydrodynamical simulations at redshifts 1 and 2, finding that alignment trends are consistent with previous studies. However, we find that the magnitude of the spin alignment signal is ∼2.4× weaker than seen in previous studies of the Horizon-AGN simulation, suggesting that this signal may have a significant dependence on subgrid physics. Based on IllustrisTNG, we then construct mock observational spectroscopic surveys that can probe shape–cosmic web alignment at z ∼ 1–2, modeled on the low- z galaxy redshift and IGM tomography surveys on the upcoming Subaru Prime Focus Spectrograph Galaxy Evolution (PFS GE) survey. However, even over box sizes of L = 205 h ^−1 Mpc, we find that global anisotropies induce a sample variance in the 2D projected alignment signal that depend on the projected direction; this induces significant errors in the observed alignment. We predict a 5.3 σ detection of IllustrisTNG’s shape alignment signal at z ∼ 1 from Subaru PFS GE, although a detection would be challenging at z ∼ 2. However, a rough rescaling of the relative alignment signal strengths between the TNG and Horizon-AGN simulations suggests that PFS GE should be able to more easily constrain the latter’s stronger signal. |
| first_indexed | 2024-03-12T02:57:08Z |
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| issn | 1538-4357 |
| language | English |
| last_indexed | 2024-03-12T02:57:08Z |
| publishDate | 2023-01-01 |
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| series | The Astrophysical Journal |
| spelling | doaj.art-76cba8b8189f4902b6c1b4907d2b41232023-09-03T15:13:20ZengIOP PublishingThe Astrophysical Journal1538-43572023-01-0195414910.3847/1538-4357/ace695Alignments between Galaxies and the Cosmic Web at z ∼ 1–2 in the IllustrisTNG SimulationsBenjamin Zhang0https://orcid.org/0000-0003-1465-135XKhee-Gan Lee1https://orcid.org/0000-0001-9299-5719Alex Krolewski2https://orcid.org/0000-0003-2183-7021Jingjing Shi3https://orcid.org/0000-0001-9879-4926Benjamin Horowitz4https://orcid.org/0000-0001-7832-5372Robin Kooistra5https://orcid.org/0000-0002-1008-6675Department of Physics and Astronomy, University of Southern California , Los Angeles, CA 90089, USA ; zhangben@usc.eduKavli IPMU (WPI), UTIAS, The University of Tokyo , Kashiwa, Chiba 277-8583, JapanPerimeter Institute for Theoretical Physics , 31 Caroline St. North, Waterloo, ON N2L 2Y5, Canada; Waterloo Centre for Astrophysics, University of Waterloo , Waterloo, ON N2L 3G1, CanadaKavli IPMU (WPI), UTIAS, The University of Tokyo , Kashiwa, Chiba 277-8583, JapanPrinceton Department of Astrophysical Sciences, Princeton, NJ 08544, USAKavli IPMU (WPI), UTIAS, The University of Tokyo , Kashiwa, Chiba 277-8583, JapanGalaxy formation theories predict that galaxy shapes and angular momenta have nonrandom alignments with the cosmic web. This leads to so-called intrinsic alignment between pairs of galaxies, which is important to quantify as a nuisance parameter for weak lensing. We study galaxy–cosmic web alignment in the IllustrisTNG suite of hydrodynamical simulations at redshifts 1 and 2, finding that alignment trends are consistent with previous studies. However, we find that the magnitude of the spin alignment signal is ∼2.4× weaker than seen in previous studies of the Horizon-AGN simulation, suggesting that this signal may have a significant dependence on subgrid physics. Based on IllustrisTNG, we then construct mock observational spectroscopic surveys that can probe shape–cosmic web alignment at z ∼ 1–2, modeled on the low- z galaxy redshift and IGM tomography surveys on the upcoming Subaru Prime Focus Spectrograph Galaxy Evolution (PFS GE) survey. However, even over box sizes of L = 205 h ^−1 Mpc, we find that global anisotropies induce a sample variance in the 2D projected alignment signal that depend on the projected direction; this induces significant errors in the observed alignment. We predict a 5.3 σ detection of IllustrisTNG’s shape alignment signal at z ∼ 1 from Subaru PFS GE, although a detection would be challenging at z ∼ 2. However, a rough rescaling of the relative alignment signal strengths between the TNG and Horizon-AGN simulations suggests that PFS GE should be able to more easily constrain the latter’s stronger signal.https://doi.org/10.3847/1538-4357/ace695Cosmic webGalaxy formationHydrodynamical simulationsIntergalactic mediumRedshift surveys |
| spellingShingle | Benjamin Zhang Khee-Gan Lee Alex Krolewski Jingjing Shi Benjamin Horowitz Robin Kooistra Alignments between Galaxies and the Cosmic Web at z ∼ 1–2 in the IllustrisTNG Simulations The Astrophysical Journal Cosmic web Galaxy formation Hydrodynamical simulations Intergalactic medium Redshift surveys |
| title | Alignments between Galaxies and the Cosmic Web at z ∼ 1–2 in the IllustrisTNG Simulations |
| title_full | Alignments between Galaxies and the Cosmic Web at z ∼ 1–2 in the IllustrisTNG Simulations |
| title_fullStr | Alignments between Galaxies and the Cosmic Web at z ∼ 1–2 in the IllustrisTNG Simulations |
| title_full_unstemmed | Alignments between Galaxies and the Cosmic Web at z ∼ 1–2 in the IllustrisTNG Simulations |
| title_short | Alignments between Galaxies and the Cosmic Web at z ∼ 1–2 in the IllustrisTNG Simulations |
| title_sort | alignments between galaxies and the cosmic web at z ∼ 1 2 in the illustristng simulations |
| topic | Cosmic web Galaxy formation Hydrodynamical simulations Intergalactic medium Redshift surveys |
| url | https://doi.org/10.3847/1538-4357/ace695 |
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