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

TL;DR

This paper provides a comprehensive UV spectral atlas of 28 local starburst and star-forming galaxies observed with HST, comparing high-resolution spectra with lower resolution data to analyze spectral features and galaxy properties.

Contribution

It introduces a new UV spectral atlas from HST observations, compares aperture effects, and develops UV line indices to study galaxy morphology and properties.

Findings

HST spectra show brighter, bluer regions with stronger stellar winds.

Interstellar medium lines are consistent across different aperture sizes.

The atlas serves as a baseline for high-redshift galaxy UV studies.

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. 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 arcsec apertures provide about 15% of the starburst luminosity traced by IUE's 10 arcsec by 20 arcsec 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 electronically. 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.