Search arXiv⌕ Search
Home/Archive/arXiv

arXiv · 0911.3368

The clustering properties of the first galaxies

M. Stiavelli·M. Trenti
View original source ↗Read source document ↗Export metadata ↓

Abstract

We study the clustering properties of the first galaxies formed in the Universe. We find that, due to chemical enrichment of the inter-stellar medium by isolated Population III stars formed in mini-halos at redshift z>30, the (chronologically) first galaxies are composed of metal-poor Population II stars and are highly clustered on small scales. In contrast, chemically pristine galaxies in halos with mass M~10^8 M_sun may form at z<20 in relatively underdense regions of the Universe. This occurs once self-enrichment by Population III in mini-halos is quenched by the build-up of an $H_2$ photo-dissociating radiative background in the Lyman-Werner bands. We find that these chemically pristine galaxies are spatially uncorrelated. Thus, we expect that deep fields with the James Webb Space Telescope may detect clusters of chemically enriched galaxies but individual chemically pristine objects. We predict that metal-free galaxies at 10 <= z <= 15$ have surface densities of about 80 per square arcmin and per unit redshift but most of them will be too faint even for JWST. However, the predicted density makes these objects interesting targets for searches behind lensing clusters.

Explore related subjects

astro-ph.CO

Keep this discovery

Explore connections, maps & timelines

BibTeXRIS

M. Stiavelli, M. Trenti. 2010-06-01. The clustering properties of the first galaxies. https://doi.org/10.1088/2041-8205%2F716%2F2%2Fl190

Cite the original work for its findings. Save a collection to share your selection of sources.

KEEP EXPLORING

Related papers

arXiv2026

Vacuum Polarization, Geodesic Equation and Sachs-Wolfe Effect

We show that the null geodesic equation for photons is modified in the presence of a charged scalar field, with quantum fluctuations acting as an effective mass term that changes the null paths to timelike curves. This effect can be interpreted as a vacuum polarization phenomenon in curved spacetime. The resulting contribution to the Sachs-Wolfe effect varies with photon frequency, leading to frequency-dependent corrections to the cosmic microwave background (CMB) blackbody spectrum in the form of a $μ$-distortion, as well as modifications to the CMB power spectrum. We estimate these within a standard inflationary scenario and find that while the correction to the CMB power spectrum is significant when the scalar field is light, the magnitude of the $μ$-distortion depends strongly on the regularization prescription.

astro-ph.CO↗
arXiv2026

Testing Bump in the Cosmological Power Spectrum Using Dwarf Galaxies

We analyze the possibility of using observational data on nearby dwarf galaxies -- their luminosity functions and spatial distributions -- to constrain deviations of the cosmological power spectrum from the standard one. Specifically, we consider a cosmological model with a "bump" in the power spectrum at a wavelength of 1.3~Mpc and a dimensionless amplitude $\mathcal{A}=2.0$. Such a spectrum is motivated by observations of an excess number of galaxies at high redshifts. The bump leads to a noticeable increase in the luminosity function in the range $-13 > M_B > -17$ at $z=0$. Comparison with observations constrains the bump amplitude to $\mathcal{A} < 0.25$ at a 3-sigma significance level for a wavelength of 1.3~Mpc. For wavelengths smaller than 0.8~Mpc, the bump manifests only in the luminosity function of dwarfs with $M_B > -14$.

astro-ph.CO↗
arXiv2026

Multi-tracers, multi-surveys: a joint Fisher analysis of DESI+PFS

Marginalizing over 11 effective-field-theory (EFT) nuisance parameters per tracer per redshift bin degrades cosmological precision in one-loop analyses of galaxy power-spectrum multipoles in redshift space. Simulation-based priors (SBP) tighten these parameters but rely on N-body simulations and halo-occupation-distribution (HOD) models. We consider a multi-tracer Fisher analysis as a complementary approach: auto- and cross-power spectra jointly constrain cosmology, galaxy bias and stochasticity through two channels -- within a survey and across overlapping surveys -- combined in a volume-partitioned joint Fisher analysis. We forecast across the $14{,}000\;\mathrm{deg}^2$ Dark Energy Spectroscopic Instrument (DESI) footprint, including the $\sim\!1{,}200\;\mathrm{deg}^2$ Prime Focus Spectrograph (PFS) overlap at $z\in[0.6,1.6]$ with up to 4 tracers (PFS-ELG, DESI-ELG, DESI-LRG, DESI-QSO). We vary a common $\ln(10^{10}A_s)$, $M_ν$ and $Ω_m$, holding $h$, $ω_b$ and $n_s$ fixed. Adding internal-DESI cross-spectra to DESI auto-spectra reduces the errors on the derived $fσ_8(z=1.1)$, $M_ν$ and $Ω_m$ by 7.1%, 3.5% and 3.8%, respectively, at $k_{\rm max}=0.20\,h\,\mathrm{Mpc}^{-1}$. Adding PFS auto- and cross-spectra to this complete DESI multi-tracer analysis further tightens these errors by 3.8%, 2.6% and 3.2%, respectively, after marginalizing over residual cross-population stochasticity. The clustering likelihood alone constrains the linear and quadratic biases and the shot noise. For these parameters it provides a complementary test of inference using SBP, while the counterterms remain weakly constrained. The framework extends to any number of overlapping spectroscopic surveys.

astro-ph.CO↗