2015ApJ...805...14R


Query : 2015ApJ...805...14R

2015ApJ...805...14R - Astrophys. J., 805, 14 (2015/May-3)

The Lyman alpha Reference Sample. V. The impact of neutral ISM kinematics and geometry on Lyα escape.

RIVERA-THORSEN T.E., HAYES M., OSTLIN G., DUVAL F., ORLITOVA I., VERHAMME A., MAS-HESSE J.M., SCHAERER D., CANNON J.M., OTI-FLORANES H., SANDBERG A., GUAITA L., ADAMO A., ATEK H., HERENZ E.C., KUNTH D., LAURSEN P. and MELINDER J.

Abstract (from CDS):

We present high-resolution far-UV spectroscopy of the 14 galaxies of the Lyα Reference Sample; a sample of strongly star-forming galaxies at low redshifts (0.028 < z < 0.18). We compare the derived properties to global properties derived from multi-band imaging and 21 cm H i interferometry and single-dish observations, as well as archival optical SDSS spectra. Besides the Lyα line, the spectra contain a number of metal absorption features allowing us to probe the kinematics of the neutral ISM and evaluate the optical depth and and covering fraction of the neutral medium as a function of line of sight velocity. Furthermore, we show how this, in combination with the precise determination of systemic velocity and good Lyα spectra, can be used to distinguish a model in which separate clumps together fully cover the background source, from the ''picket fence'' model named by Heckman et al. We find that no one single effect dominates in governing Lyα radiative transfer and escape. Lyα escape in our sample coincides with a maximum velocity-binned covering fraction of ≲0.9 and bulk outflow velocities of ≳50 km/s, although a number of galaxies show these characteristics and yet little or no Lyα escape. We find that Lyα peak velocities, where available, are not consistent with a strong backscattered component, but rather with a simpler model of an intrinsic emission line overlaid by a blueshifted absorption profile from the outflowing wind. Finally, we find a strong anticorrelation between Hα equivalent width and maximum velocity-binned covering factor, and propose a heuristic explanatory model.

Abstract Copyright:

Journal keyword(s): cosmology: observations - galaxies: ISM - galaxies: kinematics and dynamics - galaxies: starburst

Simbad objects: 14

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Number of rows : 14
N Identifier Otype ICRS (J2000)
RA
ICRS (J2000)
DEC
Mag U Mag B Mag V Mag R Mag I Sp type #ref
1850 - 2022
#notes
1 LEDA 2816291 Sy1 01 50 28.3910010185 +13 08 58.404065463           ~ 47 0
2 2MFGC 6625 EmG 08 23 54.9669334368 +28 06 21.605409814   15.5       ~ 59 0
3 SHOC 240 H2G 09 07 04.888 +53 26 56.60           ~ 26 0
4 LARS 14 EmG 09 26 00.4041863336 +44 27 36.112149583           ~ 61 0
5 LEDA 27453 Sy2 09 38 13.4918143967 +54 28 24.976826000   17.73 17.07     ~ 60 0
6 LEDA 90172 G 12 50 13.857 +07 34 44.33           ~ 37 0
7 Mrk 61 EmG 13 01 41.527 +29 22 52.84   16.96 16.65     ~ 37 0
8 LEDA 2469933 G 13 07 28.448 +54 26 52.51           ~ 17 0
9 UGC 8335 PaG 13 15 32.5 +62 07 37           ~ 57 0
10 Ton 151 AGN 13 16 03.915 +29 22 54.05   16.71 16.35     ~ 65 0
11 Mrk 259 SBG 13 28 44.000 +43 55 50.29   16.5       ~ 47 0
12 Mrk 1486 H2G 13 59 50.9093088961 +57 26 22.936953937   17.0       ~ 53 0
13 FIRST J140347.2+062811 rG 14 03 47.224 +06 28 12.18           ~ 18 0
14 LARS 6 G 15 45 44.524 +44 15 51.85           ~ 17 0

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2021.11.30-00:44:11

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