| dc.creator | Manolis Plionis | |
| dc.date | 2007 | |
| dc.date.accessioned | 2023-07-25T16:22:46Z | |
| dc.date.available | 2023-07-25T16:22:46Z | |
| dc.identifier | http://inaoe.repositorioinstitucional.mx/jspui/handle/1009/984 | |
| dc.identifier.uri | https://repositorioslatinoamericanos.uchile.cl/handle/2250/7806184 | |
| dc.description | We estimate the two-point correlation function in redshift space of the recently compiled HIPASS neutral hydrogen (HI) sources catalogue, which if modeled as a power law, ξ(r) = (r0/r)γ, the best-fitting parameters for the HI selected galaxies are found to be r0 = 3.3 ± 0.3 h−1 Mpc with γ= 1.38 ± 0.24. Fixing the slope to its universal value γ = 1.8, we obtain r0 = 3.2 ± 0.2 h−1 Mpc. Comparing the measured two point correlation function with the predictions of the concordance cosmological model (ΩΛ = 0.74), we find that at the present epoch the HI selected galaxies are anti-biased with respect to the underlying matter fluctuation field with their bias value being b0 ≃ 0.68. Furthermore, dividing the HI galaxies into two richness subsamples we find that the low mass HI galaxies have a very low present bias factor (b0 ≃ 0.48), while the high mass HI galaxies trace the underlying matter distribution as the optical galaxies (b0 ≃ 1). Using our derived present-day HI galaxy bias we
estimate their redshift space distortion parameter, and correct accordingly the correlation function for peculiar motions. The resulting real-space correlation length is rre 0 = 1.8 ± 0.2 h−1Mpc and rre0 = 3.9 ± 0.6 h−1Mpc for the low and high mass HI galaxies, respectively. The low-mass HI galaxies appear to have the lowest correlation length among all extragalactic populations studied todate. In order to corroborate these results we have correlated the IRAS-PSCz reconstructed density field, smoothed over scales of 5 h−1 Mpc, with the positions of the HI galaxies, to find that indeed the HI galaxies are typically found in negative overdensity regions (δρ / ρPSCz∼ < 0), even more so the low HI-mass galaxies. Finally, we also study the redshift evolution of the HI galaxy linear bias factor and find that the HI-galaxy population is anti-biased up to z ∼ 1.3. While at large redshifts z ∼ 3, we predict that the HI galaxies are strongly biased. Our bias evolution predictions are consistent with the observational bias results of Lyman-α galaxies. | |
| dc.format | application/pdf | |
| dc.language | eng | |
| dc.publisher | Monthly Notices of the Royal Astronomical Society | |
| dc.relation | citation:Basilakos, S., et al., (2007). Large scale structure in the HI parkes all-sky survey: filling the voids with HI galaxies?, Monthly Notices of the Royal Astronomical Society, Vol.378(1):1-9 | |
| dc.rights | info:eu-repo/semantics/openAccess | |
| dc.rights | http://creativecommons.org/licenses/by-nc-nd/4.0 | |
| dc.subject | info:eu-repo/classification/cti/1 | |
| dc.subject | info:eu-repo/classification/cti/21 | |
| dc.subject | info:eu-repo/classification/cti/21 | |
| dc.title | Large scale structure in the HI parkes all-sky survey: filling the voids with HI galaxies? | |
| dc.type | info:eu-repo/semantics/article | |
| dc.type | info:eu-repo/semantics/acceptedVersion | |
| dc.audience | students | |
| dc.audience | researchers | |
| dc.audience | generalPublic | |
