학술논문
Physical properties of Lyman-alpha emitters at $z\sim 0.3$ from UV-to-FIR measurements
Document Type
Working Paper
Author
Oteo, I.; Bongiovanni, A.; García, A. M. Pérez; Cepa, J.; Ederoclite, A.; Sánchez-Portal, M.; Pintos-Castro, I.; Pérez-Martínez, R.; Lutz, D.; Altieri, B.; Andreani, P.; Aussel, H.; Berta, S.; Cimatti, A.; Daddi, E.; Elbaz, D.; Schreiber, N. Förster; Genzel, R.; Floc'h, E. Le; Magnelli, B.; Maiolino, R.; Poglitsch, A.; Popesso, P.; Pozzi, F.; Riguccini, L.; Sturm, E.; Tacconi, L.; Valtchanov, I.
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Subject
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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.
Comment: Accepted for publication in ApJ
Comment: Accepted for publication in ApJ