An Ultraviolet Spectroscopic Atlas of Local Starbursts and Star-Forming Galaxies: The Legacy of Fos and GHRS

Abstract

We present 46 rest-frame ultraviolet (UV) spectra of 28 local starburst and star-forming galaxies which were observed with the Faint Object Spectrograph (FOS) and the Goddard High Resolution Spectrograph (GHRS) of the Hubble Space Telescope (HST) at a spectral resolution of a few 100 km s −1 . We compare the HST spectra with lower resolution International Ultraviolet Explorer (IUE) spectra of the same galaxies and find systematic differences: the bright star clusters targeted in HST's ∼1 apertures provide about 15% of the starburst luminosity traced by IUE's 10 × 20 aperture; they are bluer and have stronger stellar-wind features suggesting that the HST apertures have preferentially been placed on the youngest areas of the burst. In contrast, lines arising from the interstellar medium (ISM) show similar equivalent widths in both the large and small aperture observations, suggesting similar ISM properties from larger to smaller scales. In order to quantify the UV spectral morphology of star-forming galaxies, we created a set of UV line indices similar to the standard optical Lick indices. We discuss the relation between the UV spectral morphology and the properties of the galaxy host. We present our atlas of FOS and GHRS spectra both in print and online. The data set is useful as a baseline for comparisons with observations of the rest-frame UV spectra of star-forming galaxies at high redshift.Key words: atlases -galaxies: high-redshift -galaxies: starburst -galaxies: stellar content -line: profilesultraviolet: galaxies Online-only material: color figures 1. MOTIVATION While our understanding of galaxy formation and evolution is in many ways incomplete, it has become increasingly evident that much of the stellar mass in the universe was assembled in violent and short-lived episodes of star formation at high redshift (e.g., Papovich et al. 2001;Shapley et al. 2001;Pérez-González et al. 2008). In the latter half of the Hubble time, the overall star formation rate of the universe has declined precipitously (Lilly et al. 1996;Cowie et al. 1999;Hopkins 2004). Nevertheless, there remain present-day examples of galaxies undergoing intense bursts of star formation. Indeed, while few in number, these starburst galaxies are responsible for ∼20% of the entire high-mass star formation in the local universe (Brinchmann et al. 2004). Local starburst galaxies provide us with an opportunity to investigate in detail a phenomenon with profound cosmic consequences.In this study, we examine the UV spectral properties of 28 local starburst galaxies which were observed with the Faint Object Spectrograph (FOS) and the Goddard High Resolution Spectrograph (GHRS) instruments on board the Hubble Space Telescope (HST). The rest-frame UV is of particular interest because it is the window onto the high-redshift universe provided by large ground-based telescopes working in the visible. Our study complements the earlier work of Kinney et al. (1993) and Heckman et al. (1998; hereafter H98) based on spectra obtained with the Internation...

A young star-forming galaxy at z = 3.5 with an extended Lyman α halo seen with MUSE

“…6 of Sommariva et al 2012). Other gas metallicity indicators were reported in Christensen et al (2012b): R23, Ne3O2 and a direct measurement, yielding metallicities of 7.74 ± 0.03, 7.56 ± 0.11 and 7.76 ± 0.03 in 12+log (O/H), respectively, compatible to our estimations from the comparison with the Leitherer et al (2011) local galaxy sample.…”

“…Green dots: data from local galaxies ( fig. 15 of Leitherer et al 2011). Red line: equivalent width obtained for system 1 (dashed lines correspond to the error).…”

“…analysis (0.07 Z ), which is also the lowest possible metallicity in the STARBURST99 models, and which once more suggests that this is a low stellar metallicity system. We also use a similar method to explore the ISM metallicity, following Leitherer et al (2011) prescription to calculate the equivalent width of several ISM absorption lines. In their work, a sample of local galaxies with known metallicities is used to study how these features would correlate with metallicity, concluding that the Si II λ1260, O I and Si II λ1303 blend, C II λ1334 and Si II λ1526 absorptions are correlated to galaxy metallicity.…”

“…10 we present the local galaxy measurements from fig. 15 of Leitherer et al (2011), adding in our object for comparison. Although it is not possible to directly estimate metallicity following this method, our equivalent width measurements seem to follow the overall correlation of galaxies at low metallicities, with 12 + log (O/H) ∼ 7.5-7.9, which corresponds to a solar metallicity of 0.065 to 0.16 Z , a value that is comparable or slightly higher than the stellar metallicity, a trend that is found in other high-redshift galaxies ( fig.…”

“…In particular, Peeples, Pogge & Stanek (2009) investigated a set of massive galaxies, noticing that many had high SFRs and disturbed morphologies, indicating a Figure 10. ISM metallicity trends of various indices from Leitherer et al (2011). Green dots: data from local galaxies ( fig.…”