THE CURIOUS CASE OF Ly{alpha} EMITTERS: GROWING YOUNGER FROM z {approx} 3 to z {approx} 2?

Journal Article · Fri Jun 01 04:00:00 EDT 2012 · Astrophysical Journal Letters

DOI:https://doi.org/10.1088/2041-8205/751/2/L26· OSTI ID:22047798

Acquaviva, Viviana; Vargas, Carlos; Gawiser, Eric ^[1]; Guaita, Lucia ^[2]

---

1. Department of Physics and Astronomy, Rutgers, The State University of New Jersey, Piscataway, NJ 08854 (United States)
2. Institutionen foer Astronomi, Stockholms Universitet, SE-106 91 Stockholm (Sweden)

Ly{alpha} emitting (LAE) galaxies are thought to be progenitors of present-day L* galaxies. Clustering analyses have suggested that LAEs at z {approx} 3 might evolve into LAEs at z {approx} 2, but it is unclear whether the physical nature of these galaxies is compatible with this hypothesis. Several groups have investigated the properties of LAEs using spectral energy distribution (SED) fitting, but direct comparison of their results is complicated by inconsistencies in the treatment of the data and in the assumptions made in modeling the stellar populations, which are degenerate with the effects of galaxy evolution. By using the same data analysis pipeline and SED fitting software on two stacked samples of LAEs at z = 3.1 and z = 2.1, and by eliminating several systematic uncertainties that might cause a discrepancy, we determine that the physical properties of these two samples of galaxies are dramatically different. LAEs at z = 3.1 are found to be old (age {approx}1 Gyr) and metal-poor (Z < 0.2 Z{sub Sun }), while LAEs at z = 2.1 appear to be young (age {approx}50 Myr) and metal-rich (Z > Z{sub Sun }). The difference in the observed stellar ages makes it very unlikely that z 3.1 LAEs evolve directly into z = 2.1 LAEs. Larger samples of galaxies, studies of individual objects, and spectroscopic measurements of metallicity at these redshifts are needed to confirm this picture, which is difficult to reconcile with the effects of 1 Gyr of cosmological evolution.

• OSTI ID: 22047798
• Journal Information: Astrophysical Journal Letters, Journal Name: Astrophysical Journal Letters Journal Issue: 2 Vol. 751; ISSN 2041-8205
• Country of Publication: United States
• Language: English

Related Subjects

79 ASTRONOMY AND ASTROPHYSICS
ASTRONOMY
ASTROPHYSICS
COMPARATIVE EVALUATIONS
COMPUTER CODES
COMPUTERIZED SIMULATION
DATA ANALYSIS
ENERGY SPECTRA
GALACTIC EVOLUTION
GALAXIES
GALAXY CLUSTERS
LYMAN LINES
METALS
PHYSICAL PROPERTIES
RED SHIFT