Galaxy And Mass Assembly (GAMA): Spectroscopic analysis

By Andrew M. Hopkins, S. Driver, S. Brough, M. Owers, A. Bauer, M. Gunawardhana, Michelle E. Cluver, M. Colless, C. Foster, M. Lara-López and 103 more. 2013

142 citations recorded by the source corpus.

The Galaxy And Mass Assembly (GAMA) survey is a multiwavelength photometric and spectroscopic survey, using the AAOmega spectrograph on the Anglo-Australian Telescope to obtain spectra for up to ∼300 000 galaxies over 280 deg2, to a limiting magnitude of rpet < 19.8 mag. The target galaxies are distributed over 0 < z ≲ 0.5 with a median redshift of z ≈ 0.2, although the redshift distribution includes a small number of systems, primarily quasars, at higher redshifts, up to and beyond z = 1. The redshift accuracy ranges from σv ≈ 50 km s−1 to σv ≈ 100 km s−1 depending on the signal-to-noise ratio of the spectrum. Here we describe the GAMA spectroscopic reduction and analysis pipeline. We present the steps involved in taking the raw two-dimensional spectroscopic images through to flux-calibrated one-dimensional spectra. The resulting GAMA spectra cover an observed wavelength range of 3750 ≲ λ ≲ 8850 A at a resolution of R ≈ 1300. The final flux calibration is typically accurate to 10–20 per cent, although the reliability is worse at the extreme wavelength ends, and poorer in the blue than the red. We present details of the measurement of emission and absorption features in the GAMA spectra. These measurements are characterized through a variety of quality control analyses detailing the robustness and reliability of the measurements. We illustrate the quality of the measurements with a brief exploration of elementary emission line properties of the galaxies in the GAMA sample. We demonstrate the luminosity dependence of the Balmer decrement, consistent with previously published results, and explore further how Balmer decrement varies with galaxy mass and redshift. We also investigate the mass and redshift dependencies of the [N II]/Hα versus [O III]/Hβ spectral diagnostic diagram, commonly used to discriminate between star forming and nuclear activity in galaxies.

Subfields: Astronomy and Astrophysics, Instrumentation

View Paper: https://www.semanticscholar.org/paper/3f2208b82611ee8adbba440dc85247259b61cf88

How researchers see this paper

The researchers whose trusted networks rank it highest, strongest advocate first. Every researcher gets a different order.

In Astronomy and Astrophysics

In Instrumentation

Citations in the corpus

The SAMI Galaxy Survey: Instrument specification and target selection (2014, methodology): “The GAMA project brings together multi-wavelength data from the far-UV to infrared, and is centred around a singlefibre galaxy redshift survey (Hopkins et al. 2013) that was observed from 2008-2014 using the 2dF instrument with the AAOmega spectrograph on the AAT.”
Galaxy and mass assembly (GAMA): End of survey report and data release 2 (2015, methodology): “…galaxies (e.g. De Lucia et al. 2006), morphological transformations (e.g. Toomre 1977; Cox et al. 2006; Hopkins et al. 2009), triggering (e.g. Hopkins et al. 2013a; Patton et al. 2013) and truncating (e.g. Hopkins et al. 2008) star formation, fuelling central supermassive black holes (e.g.…”
GALAXY AND MASS ASSEMBLY (GAMA): MID-INFRARED PROPERTIES AND EMPIRICAL RELATIONS FROM WISE (2014, methodology): “Reduction and analysis of the spectra is discussed in detail in Hopkins et al. (2013) and J. Liske et al. (in preparation).”
Galaxy And Mass Assembly (GAMA): mass–size relations of z < 0.1 galaxies subdivided by Sérsic index, colour and morphology (2014, methodology): “All imaging data have matched aperture photometry (Hill et al. 2011; Liske et al. 2014) and the spectroscopic redshifts (Baldry et al. 2014; Liske et al. 2014) are based on spectra taken with AAOmega (resolution of R ∼ 1300) at the 3.9 m Anglo-Australian-Telescope (Hopkins et al. 2013) located at Si”
THE DATA REDUCTION PIPELINE FOR THE SDSS-IV MaNGA IFU GALAXY SURVEY (2016, methodology): “For survey-style operations, the SAMI survey has adopted a two-stage approach, combining a general-purpose spectroscopic pipeline 2dfdr (Hopkins et al. 2013) with a custom three-dimensional stage to assemble IFU data cubes from individual fiber spectra (Sharp et al. 2015).”