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arXiv 2408.03584astro-ph.COastro-ph.GA
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来自高红移恒星质量密度的原初磁场约束

Constraints on Primordial Magnetic Fields from High Redshift Stellar Mass Density

Qile Zhang, Shang Li, Xiu-Hui Tan, Jun-Qing Xia

AI总结:

本研究利用14个高红移(z>6)恒星质量密度数据点约束原初磁场参数,在95%置信水平下得到B0<4.44 nG和nB<-2.24的上限,并表明合适的原初磁场参数可在不显著提高恒星形成效率的情况下解释JWST早期观测结果。

摘要:

原初磁场(PMFs)在影响原初密度场中的小尺度涨落方面起着关键作用,从而在ΛCDM模型的小尺度范围内增强物质功率谱。这些被放大的涨落加速了星系晕和恒星的早期形成,这可以通过先进的高红移观测技术进行观测。因此,恒星质量密度(SMD)观测为在小尺度和高红移下对星系进行详细研究提供了重要机会,为小尺度宇宙现象提供了新的视角,并约束了PMFs的特性。在本研究中,我们汇编了红移z > 6处的14个SMD数据点,并对PMFs的参数导出了严格的约束,这些参数包括在特征尺度λ=1 Mpc处的磁场幅度,记为B0,以及磁场功率谱的谱指数nB。在95%置信水平下,我们建立了B0 < 4.44 nG和nB < -2.24的上限,以及大约f*^0 ~ 0.1的恒星形成效率。如果我们将nB固定在特定值,例如-2.85、-2.9和-2.95,则磁场幅度的95%上限可以分别被约束为1.33 nG、2.21 nG和3.90 nG。最后,我们尝试利用PMFs理论解释詹姆斯·韦布空间望远镜(JWST)最近提供的早期观测结果,并发现通过选择合适的PMF参数,可以在不显著提高恒星形成效率的情况下解释这些结果。

英文摘要:

Primordial magnetic fields (PMFs) play a pivotal role in influencing small-scale fluctuations within the primordial density field, thereby enhancing the matter power spectrum within the context of the $Λ$CDM model at small scales. These amplified fluctuations accelerate the early formation of galactic halos and stars, which can be observed through advanced high-redshift observational techniques. Therefore, Stellar Mass Density (SMD) observations, which provide significant opportunities for detailed studies of galaxies at small scales and high redshifts, offer a novel perspective on small-scale cosmic phenomena and constrain the characteristics of PMFs. In this study, we compile 14 SMD data points at redshifts $z > 6$ and derive stringent constraints on the parameters of PMFs, which include the amplitude of the magnetic field at a characteristic scale of $λ=1\,{\rm Mpc}$, denoted as $B_0$, and the spectral index of the magnetic field power spectrum, $n_{\rm B}$. At 95\% confidence level, we establish upper limits of $B_0 < 4.44$ nG and $n_{\rm B} < -2.24$, along with a star formation efficiency of approximately $f_*^0 \sim 0.1$. If we fix $n_{\rm B}$ at specific values, such as $-2.85$, $-2.9$, and $-2.95$, the 95\% upper limits for the amplitude of the magnetic field can be constrained to 1.33 nG, 2.21 nG, and 3.90 nG, respectively. Finally, we attempt to interpret recent early observations provided by James Webb Space Telescope (JWST) using the theory of PMFs, and find that by selecting appropriate PMF parameters, it is possible to explain these results without significantly increasing the star formation efficiency.

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