DUST EXTINCTION FROM BALMER DECREMENTS OF STAR-FORMING GALAXIES AT 0.75 %26lt;= z %26lt; 1.5 WITH HUBBLE SPACE TELESCOPE/WIDE-FIELD-CAMERA 3 SPECTROSCOPY FROM THE WFC3 INFRARED SPECTROSCOPIC PARALLEL SURVEY

作者：Dominguez A^*; Siana B; Henry A L; Scarlata C; Bedregal A G; Malkan M; Atek H; Ross N R; Colbert J W; Teplitz H I; Rafelski M; McCarthy P; Bunker A; Hathi N P; Dressler A; Martin C L; Masters D

来源：Astrophysical Journal, 2013, 763(2): 145.

DOI：10.1088/0004-637X/763/2/145

• dust, extinction
• galaxies: evolution
• galaxies: high-redshift

Spectroscopic observations of H alpha and H beta emission lines of 128 star-forming galaxies in the redshift range 0.75 %26lt;= z %26lt;= 1.5 are presented. These data were taken with slitless spectroscopy using the G102 and G141 grisms of theWide-Field-Camera 3 (WFC3) on board the Hubble Space Telescope as part of the WFC3 Infrared Spectroscopic Parallel survey. Interstellar dust extinction is measured from stacked spectra that cover the Balmer decrement (H alpha/H beta). We present dust extinction as a function of H alpha luminosity (down to 3 x 10(41) erg s(-1)), galaxy stellar mass (reaching 4 x 10(8) M-circle dot), and rest-frame H alpha equivalent width. The faintest galaxies are two times fainter in H alpha luminosity than galaxies previously studied at z similar to 1.5. An evolution is observed where galaxies of the same H alpha luminosity have lower extinction at higher redshifts, whereas no evolution is found within our error bars with stellar mass. The lower H alpha luminosity galaxies in our sample are found to be consistent with no dust extinction. We find an anti-correlation of the [O III] lambda 5007/H alpha flux ratio as a function of luminosity where galaxies with L-H alpha %26lt; 5 x 10(41) erg s(-1) are brighter in [O III] lambda 5007 than H alpha. This trend is evident even after extinction correction, suggesting that the increased [O III] lambda 5007/H alpha ratio in low-luminosity galaxies is likely due to lower metallicity and/or higher ionization parameters.

• 出版日期2013-2-1