Physical properties of Lyman-alpha emitters at $z\sim 0.3$ from UV-to-FIR measurements

Abstract

The analysis of the physical properties of low-redshift Ly$\alpha$ emitters (LAEs) can provide clues in the study of their high-redshift analogues. At $z\sim 0.3$, LAEs are bright enough to be detected over almost the entire electromagnetic spectrum and it is possible to carry out a more precise and complete study than at higher redshifts. In this study, we examine the UV and IR emission, dust attenuation, SFR and morphology of a sample of 23 GALEX-discovered star-forming (SF) LAEs at $z\sim 0.3$ with direct UV (GALEX), optical (ACS) and FIR (PACS and MIPS) data. Using the same UV and IR limiting luminosities, we find that LAEs at $z\sim 0.3$ tend to be less dusty, have slightly higher total SFRs, have bluer UV continuum slopes, and are much smaller than other galaxies that do not exhibit Ly$\alpha$ emission in their spectrum (non-LAEs). These results suggest that at $z\sim 0.3$ Ly$\alpha$ photons tend to escape from small galaxies with low dust attenuation. Regarding their morphology, LAEs belong to Irr/merger classes, unlike non-LAEs. Size and morphology represent the most noticeable difference between LAEs and non-LAEs at $z\sim 0.3$. Furthermore, the comparison of our results with those obtained at higher redshifts indicates that either the Ly$\alpha$ technique picks up different kind of galaxies at different redshifts or that the physical properties of LAEs are evolving with redshift.

Accepted for publication in ApJ

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Cited by in corpus (12)

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• The CALYMHA survey: Lya luminosity function and global escape fraction of Lya photons at z=2.23
• Far-infrared surveys of galaxy evolution
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• Search for [CII] emission in z=6.5-11 star-forming galaxies
• Lyman Alpha and MgII as Probes of Galaxies and their Environments
• The X-ray and radio activity of typical and luminous Lya emitters from z~2 to z~6: evidence for a diverse, evolving population
• Herschel Far-IR counterparts of SDSS galaxies: Analysis of commonly used Star Formation Rate estimates
• The UV to FIR spectral energy distribution of star-forming galaxies in the redshift desert
• Lyman break and UV-selected galaxies at z ~ 1: II. PACS-100um/160um FIR detections
• Trident: A three-pronged galaxy survey. I. Lyman alpha emitting galaxies at z~2 in GOODS North
• Lyman break and UV-selected galaxies at $z\sim 1$ I. Stellar populations from ALHAMBRA survey