Astronomy and Astrophysics – Astrophysics – Cosmology and Extragalactic Astrophysics
Scientific paper
2011-11-04
Astronomy and Astrophysics
Astrophysics
Cosmology and Extragalactic Astrophysics
Scientific paper
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 and resolution (S/N = 132 - 4760 at {Dlambda = 1 A), 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 http://www.vo.elte.hu/compositeatlas.
Budavari Tamas
Csabai István
Dobos László
Szalay Alexander S.
Wild Vivienne
No associations
LandOfFree
A High Resolution Atlas of Composite SDSS Galaxy Spectra does not yet have a rating. At this time, there are no reviews or comments for this scientific paper.
If you have personal experience with A High Resolution Atlas of Composite SDSS Galaxy Spectra, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and A High Resolution Atlas of Composite SDSS Galaxy Spectra will most certainly appreciate the feedback.
Profile ID: LFWR-SCP-O-101650