- The paper demonstrates that BECDM produces distinct quantum interference patterns in cosmic filaments compared to CDM and WDM.
- It utilizes high-resolution 1.7 h⁻¹ Mpc simulations at z ≥ 5 to capture early galaxy formation and solitonic halo cores.
- The study implies BECDM can address small-scale issues like the cusp-core problem, offering new insights into dark matter behavior.
The paper, titled "Galaxy Formation with BECDM - II. Cosmic Filaments and First Galaxies," examines the implications of forming galaxies under the Bose-Einstein Condensate Dark Matter (BECDM) cosmology. This work highlights notable differences in cosmic structure formation when compared to the prevailing Cold Dark Matter (CDM) model, and it also compares results with a Warm Dark Matter-like (WDM) model, which approximates BECDM by ignoring its dynamical quantum potential but considering the initial suppression of the power spectrum. The primary objective is to ascertain the viability of BECDM as an alternative cosmological model to explain the small-scale structure formation in the universe.
Key Findings
- Simulations Configuration and Scale: The simulations analyze BECDM, CDM, and WDM cosmologies coupled with baryonic physics using a comoving box of 1.7 h−1 Mpc at high redshifts ( z≥5 ). This setup is designed to explore the first galaxies formed under these models, using a boson mass of m=2.5×10−22 eV.
- Cosmic Structure and Filament Formation: The research identifies that BECDM and WDM exhibit a filamentary cosmic structure, whereas CDM reflects subhalo presence. Particularly in BECDM, filaments showcase quantum interference patterns attributed to the wavelike characteristics of the BECDM particles. This distinction is absent in WDM, where structures lack these quantum effects, demonstrating a unique signature of BECDM at small scales.
- Halo and Filament Star Formation: In comparing the timeline of star formation, BECDM/WDM demonstrate a delayed onset compared to CDM. For instance, in BECDM, the first stars form at redshifts z∼13, in contrast to z∼35 in CDM. BECDM structures show reduced star formation and delayed metal enrichment, emphasizing the impacts of inhibited small-scale structure formation inherent to BECDM and WDM cosmologies.
- Triaxiality and Halo Density Profiles: BECDM displays enhanced halo triaxiality compared to CDM, suggesting increased ellipticity due to sustained filamentary structures. The dark matter profiles in BECDM reveal central soliton cores formed due to a coherent interference of wavelike matter, differing significantly from the NFW-like cusps observed in CDM halos.
- Dark Matter Power Spectra Developments: While initially similar across models, the evolved power spectra bring out pronounced differences at smaller scales by z∼7. BECDM adds small-scale power compared to WDM, highlighting quantum dynamical contributions from interference patterns that leave distinct cosmological imprints.
Implications and Speculations
The findings from these simulations solidify the potential of BECDM in resolving some of the small-scale challenges faced by CDM, such as the "cusp-core" problem and providing an explanation for dark matter characteristics at galactic centers. The solitonic cores and unique interference patterns are significant BECDM signatures that could be detectable through astronomical observations in the future.
Future work could explore how BECDM impacts galaxy formation statistics and the alignment of galaxy angular momentum with cosmic filaments. There is a solid foundation here to also explore how different boson masses and interactions may influence the small-scale universe further.
Conclusion
This exploration into BECDM cosmology offers insightful perspectives into alternative dark matter paradigms and introduces distinctive structural formations diverging from classical CDM models. Through comprehensive simulations, the paper elevates BECDM as a compelling candidate that could address long-standing discrepancies in galactic scale predictions, inviting further investigation and observation to validate its cosmological role.