In:
The Astrophysical Journal Supplement Series, American Astronomical Society, Vol. 261, No. 2 ( 2022-08-01), p. 31-
Abstract:
Far-ultraviolet (FUV; ∼1200–2000 Å) spectra are fundamental to our understanding of star-forming galaxies, providing a unique window on massive stellar populations, chemical evolution, feedback processes, and reionization. The launch of the James Webb Space Telescope will soon usher in a new era, pushing the UV spectroscopic frontier to higher redshifts than ever before; however, its success hinges on a comprehensive understanding of the massive star populations and gas conditions that power the observed UV spectral features. This requires a level of detail that is only possible with a combination of ample wavelength coverage, signal-to-noise, spectral-resolution, and sample diversity that has not yet been achieved by any FUV spectral database. We present the Cosmic Origins Spectrograph Legacy Spectroscopic Survey (CLASSY) treasury and its first high-level science product, the CLASSY atlas. CLASSY builds on the Hubble Space Telescope (HST) archive to construct the first high-quality (S/N 1500 Å ≳ 5/resel), high-resolution ( R ∼ 15,000) FUV spectral database of 45 nearby (0.002 〈 z 〈 0.182) star-forming galaxies. The CLASSY atlas, available to the public via the CLASSY website, is the result of optimally extracting and coadding 170 archival+new spectra from 312 orbits of HST observations. The CLASSY sample covers a broad range of properties including stellar mass (6.2 〈 log M ⋆ ( M ⊙ ) 〈 10.1), star formation rate (−2.0 〈 log SFR ( M ⊙ yr −1 ) 〈 +1.6), direct gas-phase metallicity (7.0 〈 12+log(O/H) 〈 8.8), ionization (0.5 〈 O 32 〈 38.0), reddening (0.02 〈 E ( B − V ) 〈 0.67), and nebular density (10 〈 n e (cm −3 ) 〈 1120). CLASSY is biased to UV-bright star-forming galaxies, resulting in a sample that is consistent with the z ∼ 0 mass–metallicity relationship, but is offset to higher star formation rates by roughly 2 dex, similar to z ≳ 2 galaxies. This unique set of properties makes the CLASSY atlas the benchmark training set for star-forming galaxies across cosmic time.
Type of Medium:
Online Resource
ISSN:
0067-0049
,
1538-4365
DOI:
10.3847/1538-4365/ac6c03
Language:
Unknown
Publisher:
American Astronomical Society
Publication Date:
2022
detail.hit.zdb_id:
2006860-8
detail.hit.zdb_id:
2207650-5
SSG:
16,12
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