A high-resolution atlas of composite Sloan Digital Sky Survey galaxy spectra

László Dobos, I. Csabai, Ching Wa Yip, Tamás Budavári, Vivienne Wild, Alexander S. Szalay

Research output: Contribution to journalArticle

22 Citations (Scopus)

Abstract

In this work we present an atlas of composite spectra of galaxies based on the data of the Sloan Digital Sky Survey Data Release 7 (SDSS DR7). Galaxies are classified by colour, nuclear activity and star formation activity to calculate average spectra of high signal-to-noise ratio (S/N) and resolution (at Δλ= 1Å), using an algorithm that is robust against outliers. Besides composite spectra, we also compute the first five principal components of the distributions in each galaxy class to characterize the nature of variations of individual spectra around the averages. The continua of the composite spectra are fitted with BC03 stellar population synthesis models to extend the wavelength coverage beyond the coverage of the SDSS spectrographs. Common derived parameters of the composites are also calculated: integrated colours in the most popular filter systems, line-strength measurements and continuum absorption indices (including Lick indices). These derived parameters are compared with the distributions of parameters of individual galaxies, and it is shown on many examples that the composites of the atlas cover much of the parameter space spanned by SDSS galaxies. By co-adding thousands of spectra, a total integration time of several months can be reached, which results in extremely low noise composites. The variations in redshift not only allow for extending the spectral coverage bluewards to the original wavelength limit of the SDSS spectrographs, but also make higher spectral resolution achievable. The composite spectrum atlas is available online at.

Original languageEnglish
Pages (from-to)1217-1238
Number of pages22
JournalMonthly Notices of the Royal Astronomical Society
Volume420
Issue number2
DOIs
Publication statusPublished - Feb 2012

Fingerprint

atlas
galaxies
composite materials
high resolution
spectrographs
continuums
wavelength
color
outlier
spectral resolution
wavelengths
signal-to-noise ratio
low noise
star formation
signal to noise ratios
filter
filters
parameter
synthesis

Keywords

  • Atlases
  • Galaxies: Statistics
  • Methods: Statistical
  • Surveys
  • Techniques: Spectroscopic

ASJC Scopus subject areas

  • Space and Planetary Science
  • Astronomy and Astrophysics

Cite this

A high-resolution atlas of composite Sloan Digital Sky Survey galaxy spectra. / Dobos, László; Csabai, I.; Yip, Ching Wa; Budavári, Tamás; Wild, Vivienne; Szalay, Alexander S.

In: Monthly Notices of the Royal Astronomical Society, Vol. 420, No. 2, 02.2012, p. 1217-1238.

Research output: Contribution to journalArticle

Dobos, László ; Csabai, I. ; Yip, Ching Wa ; Budavári, Tamás ; Wild, Vivienne ; Szalay, Alexander S. / A high-resolution atlas of composite Sloan Digital Sky Survey galaxy spectra. In: Monthly Notices of the Royal Astronomical Society. 2012 ; Vol. 420, No. 2. pp. 1217-1238.
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