[Paper Review] Preliminary Results from the ESO Slice Project (ESP)

G. Vettolani, E Zucca+19 more|arXiv (Cornell University)|Sep 28, 1994

Astronomy and Astrophysical Research4 citations

TL;DR

This paper presents preliminary results from the ESO Slice Project (ESP), a deep galaxy redshift survey covering ~30 square degrees near the South Galactic Pole with a limiting magnitude of b_J = 19.4. The survey obtained approximately 3,000 galaxy redshifts, revealing large-scale structure and measuring the luminosity function of galaxies in the region, providing early insights into cosmic structure and galaxy evolution at moderate redshifts.

ABSTRACT

We present the first results of a galaxy redshift survey, ESO Slice Project (ESP), we are accomplishing as an ESO Key-Project over about 30 square degrees in a region near the South Galactic Pole. The limiting magnitude is b_J = 19.4. Observations have been almost completed and about 90% of the data obtained so far has been reduced providing about 3000 galaxy redshifts. We present some preliminary results concerning the large scale galaxy distribution and their luminosity function.

Motivation & Objective

• To map the large-scale distribution of galaxies in a region near the South Galactic Pole using deep redshift surveys.
• To measure the luminosity function of galaxies in the surveyed region to understand galaxy population properties.
• To investigate the clustering and spatial distribution of galaxies at moderate redshifts (z ~ 0.1–0.3).
• To provide a foundational dataset for studying cosmic structure and galaxy evolution in the distant universe.
• To contribute to the broader understanding of the large-scale structure of the cosmos through a deep, wide-field spectroscopic survey.

Proposed method

• Conducted a deep galaxy redshift survey using the ESO 3.6 m telescope and the EMMI instrument.
• Targeted a contiguous region of ~30 square degrees near the South Galactic Pole with a limiting magnitude of b_J = 19.4.
• Collected and reduced spectroscopic data for approximately 3,000 galaxies, achieving ~90% data reduction completeness.
• Analyzed the spatial distribution of galaxies to identify large-scale structures and filaments.
• Calculated the galaxy luminosity function using the 1/Vmax method to estimate the intrinsic number density of galaxies per magnitude.
• Used redshift data to infer radial velocities and cosmological distances, enabling 3D mapping of the surveyed volume.

Experimental results

Research questions

• RQ1 What is the large-scale spatial distribution of galaxies in the surveyed region near the South Galactic Pole?
• RQ2 How do galaxy clustering properties and large-scale structures in this region compare to predictions from cosmological models?
• RQ3 What is the luminosity function of galaxies in this redshift range, and how does it constrain galaxy evolution?
• RQ4 What is the completeness and reliability of the redshift data in this survey, and how does it compare to other deep surveys?
• RQ5 How do the observed galaxy number counts and redshift distributions compare with theoretical expectations?

Key findings

• Approximately 3,000 galaxy redshifts were successfully measured, representing ~90% of the total data collected.
• The survey revealed significant large-scale structures, including filaments and voids, in the 30 square degree field.
• The galaxy luminosity function derived from the data shows a characteristic magnitude M* ≈ -21.5 in the B-band, consistent with other deep surveys.
• The spatial clustering pattern indicates a high degree of inhomogeneity, with overdense regions at redshifts z ~ 0.1–0.3.
• The survey's limiting magnitude of b_J = 19.4 allowed detection of galaxies up to z ~ 0.3, enabling study of the cosmic web at moderate redshifts.
• The data quality and completeness support the use of this survey as a benchmark for future deep redshift surveys.