GHASP : An Halpha kinematic survey of 203 spiral and irregular galaxies - VII. Revisiting the analysis of Halpha data cubes for 97 galaxies

TL;DR

The GHASP survey provides a comprehensive, uniformly analyzed set of Halpha kinematic data for 203 spiral and irregular galaxies, including new reduction techniques, kinematic parameters, and flux measurements, enhancing the understanding of galaxy dynamics.

Contribution

This paper introduces a new, homogeneous data reduction and analysis method for 97 galaxies within the GHASP survey, improving kinematic parameter accuracy and providing the first integrated Halpha profiles for the entire sample.

Findings

Enhanced accuracy of position angle measurements using kinematic data.

Difficulty in determining inclinations for low-inclination galaxies.

Strong agreement of Tully-Fisher relation with previous studies.

Abstract

The GHASP survey (Gassendi HAlpha survey of SPirals) consists of 3D Ha data cubes for 203 spiral and irregular galaxies, covering a large range in morphological types and absolute magnitudes, for kinematics analysis. It is the largest sample of Fabry-Perot data published up to now. In order to provide an homogenous sample, reduced and analyzed using the same procedure, we present in this paper the new reduction and analysis for a set of 97 galaxies already published in previous papers but now using the new data reduction procedure adopted for the whole sample. The GHASP survey is now achieved and the whole sample is reduced using adaptive binning techniques based on Voronoi tessellations. We have derived Ha data cubes from which are computed Ha maps, radial velocity fields as well as residual velocity fields, position-velocity diagrams, rotation curves and kinematical parameters for almost all galaxies. The rotation curves, the kinematical parameters and their uncertainties are computed homogeneously using the new method based on the power spectrum of the residual velocity field. This paper provides the kinematical parameters for the whole sample. For the first time, the integrated Ha profiles have been computed and are presented for the whole sample. The total Ha fluxes deduced from these profiles have been used in order to provide a flux calibration for the 203 GHASP galaxies. This paper confirms the conclusions already drawn from half the sample concerning (i) the increased accuracy of position angles measurements using kinematical data, (ii) the difficulty to have robust determinations of both morphological and kinematical inclinations in particular for low inclination galaxies and (iii) the very good agreement between the Tully-Fisher relationship derived from our data and previous determinations.