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The Lyman alpha reference sample : VII. Spatially resolved H α kinematics

Herenz, Edmund Christian; Gruyters, Pieter LU ; Orlitova, Ivana; Hayes, Matthew; Östlin, Göran; Cannon, John M.; Roth, Martin M.; Bik, Arjan; Pardy, Stephen and Otí-Floranes, Héctor, et al. (2016) In Astronomy and Astrophysics 587.
Abstract

We present integral field spectroscopic observations with the Potsdam Multi-Aperture Spectrophotometer of all 14 galaxies in the z ∼ 0.1 Lyman Alpha Reference Sample (LARS). We produce 2D line-of-sight velocity maps and velocity dispersion maps from the Balmer α (Hα) emission in our data cubes. These maps trace the spectral and spatial properties of the LARS galaxies' intrinsic Lyα radiation field. We show our kinematic maps that are spatially registered onto the Hubble Space Telescope Hα and Lyman α (Lyα) images. We can conjecture a causal connection between spatially resolved Hα kinematics and Lyα photometry for individual galaxies, however, no general trend can be established for the whole sample. Furthermore, we compute the... (More)

We present integral field spectroscopic observations with the Potsdam Multi-Aperture Spectrophotometer of all 14 galaxies in the z ∼ 0.1 Lyman Alpha Reference Sample (LARS). We produce 2D line-of-sight velocity maps and velocity dispersion maps from the Balmer α (Hα) emission in our data cubes. These maps trace the spectral and spatial properties of the LARS galaxies' intrinsic Lyα radiation field. We show our kinematic maps that are spatially registered onto the Hubble Space Telescope Hα and Lyman α (Lyα) images. We can conjecture a causal connection between spatially resolved Hα kinematics and Lyα photometry for individual galaxies, however, no general trend can be established for the whole sample. Furthermore, we compute the intrinsic velocity dispersion σ0, the shearing velocity νshear, and the νshear0 ratio from our kinematic maps. In general LARS galaxies are characterised by high intrinsic velocity dispersions (54 km s-1 median) and low shearing velocities (65 km s-1 median). The νshear0 values range from 0.5 to 3.2 with an average of 1.5. It is noteworthy that five galaxies of the sample are dispersion-dominated systems with νshear0<1, and are thus kinematically similar to turbulent star-forming galaxies seen at high redshift. When linking our kinematical statistics to the global LARS Lyα properties, we find that dispersion-dominated systems show higher Lyα equivalent widths and higher Lyα escape fractions than systems with νshear0> 1. Our result indicates that turbulence in actively star-forming systems is causally connected to interstellar medium conditions that favour an escape of Lyα radiation.

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published
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keywords
Cosmology: observations, Galaxies: ISM, Galaxies: starburst, Radiative transfer, Ultraviolet: galaxies
in
Astronomy and Astrophysics
volume
587
publisher
EDP Sciences
external identifiers
  • Scopus:84959036638
ISSN
0004-6361
DOI
10.1051/0004-6361/201527373
language
English
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yes
id
d77f407f-4032-4892-81bd-05676d86111f
date added to LUP
2016-07-14 10:05:59
date last changed
2016-11-14 12:48:19
@misc{d77f407f-4032-4892-81bd-05676d86111f,
  abstract     = {<p>We present integral field spectroscopic observations with the Potsdam Multi-Aperture Spectrophotometer of all 14 galaxies in the z ∼ 0.1 Lyman Alpha Reference Sample (LARS). We produce 2D line-of-sight velocity maps and velocity dispersion maps from the Balmer α (Hα) emission in our data cubes. These maps trace the spectral and spatial properties of the LARS galaxies' intrinsic Lyα radiation field. We show our kinematic maps that are spatially registered onto the Hubble Space Telescope Hα and Lyman α (Lyα) images. We can conjecture a causal connection between spatially resolved Hα kinematics and Lyα photometry for individual galaxies, however, no general trend can be established for the whole sample. Furthermore, we compute the intrinsic velocity dispersion σ<sub>0</sub>, the shearing velocity ν<sub>shear</sub>, and the ν<sub>shear</sub>/σ<sub>0</sub> ratio from our kinematic maps. In general LARS galaxies are characterised by high intrinsic velocity dispersions (54 km s<sup>-1</sup> median) and low shearing velocities (65 km s<sup>-1</sup> median). The ν<sub>shear</sub>/σ<sub>0</sub> values range from 0.5 to 3.2 with an average of 1.5. It is noteworthy that five galaxies of the sample are dispersion-dominated systems with ν<sub>shear</sub>/σ<sub>0</sub>&lt;1, and are thus kinematically similar to turbulent star-forming galaxies seen at high redshift. When linking our kinematical statistics to the global LARS Lyα properties, we find that dispersion-dominated systems show higher Lyα equivalent widths and higher Lyα escape fractions than systems with ν<sub>shear</sub>/σ<sub>0</sub>&gt; 1. Our result indicates that turbulence in actively star-forming systems is causally connected to interstellar medium conditions that favour an escape of Lyα radiation.</p>},
  author       = {Herenz, Edmund Christian and Gruyters, Pieter and Orlitova, Ivana and Hayes, Matthew and Östlin, Göran and Cannon, John M. and Roth, Martin M. and Bik, Arjan and Pardy, Stephen and Otí-Floranes, Héctor and Miguel Mas-Hesse, J. and Adamo, Angela and Atek, Hakim and Duval, Florent and Guaita, Lucia and Kunth, Daniel and Laursen, Peter and Melinder, Jens and Puschnig, Johannes and Rivera-Thorsen, Thøger E. and Schaerer, Daniel and Verhamme, Anne},
  issn         = {0004-6361},
  keyword      = {Cosmology: observations,Galaxies: ISM,Galaxies: starburst,Radiative transfer,Ultraviolet: galaxies},
  language     = {eng},
  month        = {03},
  publisher    = {ARRAY(0x9ec1e18)},
  series       = {Astronomy and Astrophysics},
  title        = {The Lyman alpha reference sample : VII. Spatially resolved H α kinematics},
  url          = {http://dx.doi.org/10.1051/0004-6361/201527373},
  volume       = {587},
  year         = {2016},
}