The importance of nebular emission for SED modeling of distant star-forming galaxies

We highlight and discuss the importance of accounting for nebular emission in the SEDs of high redshift galaxies, as lines and continuum emission can contribute significantly or subtly to broad-band photometry. Physical parameters such as the galaxy age, mass, star-formation rate, dust attenuation and others inferred from SED fits can be affected to different extent by the treatment of nebular emission. We analyse a large sample of Lyman break galaxies from z~3-6, and show some main results illustrating e.g. the importance of nebular emission for determinations of the mass-SFR relation, attenuation and age. We suggest that a fairly large scatter in such relations could be intrinsic. We find that the majority of objects (~60-70%) is better fit with SEDs accounting for nebular emission; the remaining galaxies are found to show relatively weak or no emission lines. Our modeling, and supporting empirical evidence, suggests the existence of two categories of galaxies, "starbursts" and "post-starbursts" (lower SFR and older galaxies) among the LBG population, and relatively short star-formation timescales.Comment: To appear in IAU Symp. 284, The Spectral Energy Distribution of Galaxies, Preston (UK), September 2011, eds. R. J. Tuffs and C. C. Popesc

Lyman alpha emitting and related star-forming galaxies at high redshift

I provide an overview about star-forming galaxies at high redshift and their physical properties. Starting from the populations of Ly-$\alpha$ emitters and Lyman break galaxies, I summarize their common features and distinction. Then I summarize recent insight onto their physical properties gained from SED models including nebular emission, and various implications from these studies on the properties of star-formation at high redshift. Finally, I present new results and an overview on the dust content and UV attenuation of $z>6$ galaxies obtained from IRAM and ALMA observations.Comment: 12 pages, 5 figures. To appear in "LESSONS FROM THE LOCAL GROUP - A Conference in Honour of David Block and Bruce Elmegreen", eds. Freeman, K.C., Elmegreen, B.G., Block, D.L. & Woolway, M. (SPRINGER: NEW YORK

Star Forming Galaxies at z > 5

We present recent progress in searching for galaxies at redshift from z = 5 to z = 10. Wide-field and senstive surveys with 8m class telescopes have been providing more than several hundreds of star forming galaxies at z =5 - 7 that are probed in the optical window. These galaxies are used to study the early cosmic star formation activity as well as the early structure formation in the universe. Moreover, near infrared deep imaging and spectropscopic surveys have found probable candidates of galaxies from z = 7 to z = 10. Although these candidates are too faint to be identified unambiguously, we human being are now going to the universe beyond 13 billion light years, close to the epoch of first-generations stars; i.e., Population III stars. We also mention about challanges to find Population III-dominated galaxies in the early universe.Comment: 8 pages, no figure, Proceeding of IAU Symposium 250, in pres