J/A+A/693/A252 LARS XV. Spatially resolved Halpha kinematics (Herenz+, 2025)
The Lyman Alpha Reference Sample.
XV. Relating ionised gas kinematics with Lyman-alpha observables.
Herenz E.C., Schaible A., Laursen P., Runnholm A., Melinder J.,
Le Reste A, Hayes M.J., Oestlin G., Cannon J., Roth M., Saha K.
<Astron. Astrophys. 693, A252 (2025)>
=2025A&A...693A.252H 2025A&A...693A.252H (SIMBAD/NED BibCode)
ADC_Keywords: Galaxies, spectra ; Galaxies, optical
Keywords: radiative transfer - galaxies: ISM -
galaxies: kinematics and dynamics - galaxies: starburst
Abstract:
Gas kinematics affect the radiative transfer and escape of hydrogen
Lyman-α (Lyα) emission from galaxies. We investigate this
interplay empirically by relating the ionised gas kinematics of 42
galaxies in the extended Lyα Reference Sample (eLARS) with their
Lyα escape fractions, fesc, Lyα equivalent widths,
EWLyα, and Lyα luminosities, LLyα. To this aim
we use PMAS integral-field spectroscopic observations of the
Balmer-α line. Our sample contains 18 rotating discs, 13
perturbed rotators, and 13 galaxies with more complex kinematics. The
distributions of fesc, EWLyα, and LLyα do not differ
significantly between these kinematical classes, but the largest
Lyα observables are found amongst the kinematically complex
systems. We find no trends between either fesc or EWLyα and
kinematic or photometric inclinations. We calculate shearing
velocities, v_s, and intrinsic velocity dispersions, σv
(empirically corrected for beam-smearing effects), as global
kinematical measures for each galaxy. The sample is characterised by
highly turbulent motions (30km/s≲σv≲80km/s) and more than
half of the sources show dispersion-dominated kinematics. We uncover
clear trends between Lyα observables and global kinematical
statistics: EWLyα and LLyα correlate with σv,
while fesc anti-correlates with vs and vs/σv. Moreover,
we find, that galaxies with EWLyα≥20Å are characterised by
higher σv and lower vs/σv than galaxies below this
threshold. We discuss the statistical importance of vs, σv,
and vs/σv for regulating the Lyα observables in
comparison to other galaxy parameters. It emerges that σv is
the dominating parameter for regulating EWLyα and that is as
important as nebular extinction, gas covering fraction, and ionising
photon production efficiency in regulating fesc. A simple scenario
where the starburst age is simultaneously regulating turbulence,
EWLyα, and fesc is not supported by our observations.
However, we show that the small-scale distribution of dust appears to
be influenced by turbulence in some galaxies. In support of our
observational result, we discuss how turbulence is theoretically
expected to play a significant role in modulating fesc.
Description:
We release the following data products for the 28 eLARS galaxies with
our paper:
- Reduced PMAS datacubes & associated error cubes in the folder
'cubes'. (The data reduction is described in Appendix A of the paper.)
The file name scheme is 'eLARSNNAcube.fits' ('eLARSNNAcube_err.fits'
for the error cubes), where 'NN' is the ID of the galaxy (01-28) and
'A' is either an underscore or one or a combination of the following
specifiers indicating the reduction procedure:
- 'skysub' if the exposure(s) for the cube were sky-subtracted
- 'stitch' for cubes that consist of more than one pointing
and which have been re-binned to a common grid.
- 'stack' for one pointing cubes consisting of multiple
exposures.
- '_' (only a single underscore) to indicate a one exposure and
non-sky subtracted cube.
- Datacubes created from the arc-lamp exposures associated with
the science observations. These cubes can be used to characterise and
quantify the line spread function. The files are in the folder 'cubes'
and named 'arceLARSNNcube.fits' ('arceLARSNNstitch_cube.fits' for
the 'stitch' cubes), with 'NN' referring to the ID of the galaxy.
- Kinematic maps of the galaxies from Gaussian
(g(LAMBDA)=AMPLITUDE*exp(-(LAMBDA-LAMBDA0)2/(2*DELTA_LAMBDA^2)))
fits to the datacube spaxels. These maps are stored in multi-HDU FITS
files in the folder 'vfit_fits'. The file name scheme is
'eLARSNNvfitwcs.fits'. The creation of the maps and the Monte Carlo
(MC) simulation to derive errors is described in Appendix B of the
paper. The individual HDUs contain 2D maps of the Gaussian parameters
as follows:
- HDU 0 (AMPLITUDE): Amplitude of the Gaussian fit.
- HDU 1 (AMPLITUDE_MC): Mean of the amplitude from 1e4 MC
realisations.
- HDU 2 (AMPLITUDEMCERR): Standard deviation of the amplitudes
from 1e4 MC realisations.
- HDU 3 (LAMBDA_0): Central wavelength of the Gaussian fit (in Angstrom).
- HDU 4 (LAMBDA0MC): Mean of the central wavelength (in
Angstrom) from 1e4 MC realisations.
- HDU 5 (LAMBDA0pMC_ERR): Standard deviation of the central
wavelengths from 1e4 MC realisations.
- HDU 6 (DELTA_LAMBDA): Width (1σ) of the Gaussian fit (in Angstrom)
- HDU 7 (DELTALAMBDAMC): Mean of the width (in Angstrom) from
1e4 MC realisations.
- HDU 8 (DELTALAMBDAMC_ERR): Standard deviation of width (in
Angstrom) from 1e4 MC realisations.
- HDU 9 (V_FWHM): Width (FWHM) of the Gaussian fit (in km/s),
calculated as VFWHM=2.335*c*DELTALAMBDA/LAMBDA_0, where
c is the speed of light.
- HDU 10 (VFWHMMC): Mean of V_FWHM over 1e4 MC realisations (in km/s).
- HDU 11 (VFWHMMC_ERR): Standard deviation of V_FWHM over 1e4
MC realisations (in km/s).
- HDU 12 (FLUX): Integrated flux from the Gaussian profile,
i.e. FLUX=sqrt(2π)*AMPLITUDE*DELTA_LAMBDA (often in
arbitrary units, as many datacubes have not been flux
calibrated).
- HDU 13 (FLUX_MC): Mean flux from 1e4 MC realisations.
- HDU 14 (FLUXMCERR): Standard deviation of the flux from 1e4
MC realisations.
Objects:
------------------------------------------------------------------
RA (2000) DE Designation(s)
------------------------------------------------------------------
16 11 40.30 +52 27 21.0 ELARS 1 = NGC 6090
13 21 09.07 +59 06 05.2 ELARS 2 = Mrk 65
11 45 11.37 +61 42 30.7 ELARS 3 = UGC 6727
17 28 23.84 +57 32 43.5 ELARS 4 = NGC 6387
11 05 01.98 +59 41 03.5 ELARS 5 = SBSG 1102+599A
11 58 40.58 +64 57 53.1 ELARS 6 = LEDA 2673269
10 12 43.04 +61 33 03.0 ELARS 7 = SDSS J101242.97+613302.8
10 30 20.88 +61 15 49.4 ELARS 8 = LEDA 30990
13 27 34.72 +66 45 16.6 ELARS 9 = LEDA 2690732
11 05 04.46 +59 39 57.3 ELARS 10 = SBSG 1102+599B
09 27 15.48 +58 36 54.4 ELARS 11 = Mrk 1417
13 06 07.14 +59 13 02.4 ELARS 12 = SBSG 1304+594
10 51 00.64 +65 59 40.6 ELARS 13 = ZW VII 348
11 27 22.10 +60 44 54.1 ELARS 14 = SBSG 1124+610
13 44 37.83 +61 14 24.4 ELARS 15 = MCG+10-20-017
13 52 09.13 +56 06 31.4 ELARS 16 = LEDA 2525836
10 26 56.31 +58 49 41.4 ELARS 17 = LEDA 2583265
15 20 53.59 +57 11 22.3 ELARS 18 = LEDA 2559518
12 05 06.35 +56 33 30.9 ELARS 19 = SDSS J120506.35+563330.8
13 38 58.15 +61 49 59.1 ELARS 20 = LEDA 2625488
14 19 11.37 +65 49 46.2 ELARS 21 = SDSS J141911.37+654946.2
17 09 12.74 +60 49 50.0 ELARS 22 = SBSG 1708+608
14 48 27.20 +63 02 10.4 ELARS 23 = SDSS J144827.20+630210.4
14 43 05.32 +61 18 38.5 ELARS 24 = SDSS J144305.31+611838.6
10 12 01.93 +60 37 20.3 ELARS 25 = KUG 1008+608
11 52 41.73 +66 18 27.4 ELARS 26 = LEDA 2685794
15 02 47.62 +62 20 18.9 ELARS 27 = LEDA 2634916
11 52 18.77 +58 56 57.1 ELARS 28 = LEDA 2584627
------------------------------------------------------------------
File Summary:
--------------------------------------------------------------------------------
FileName Lrecl Records Explanations
--------------------------------------------------------------------------------
ReadMe 80 . This file
cubes.dat 234 84 List of fits datacubes
cubes/* . 84 Individual fits datacubes
vfitmaps.dat 81 28 List of fits Kinematic maps
vfit_fits/* . 28 Individual Kinematic maps
--------------------------------------------------------------------------------
See also:
J/A+A/587/A78 : LARS VIII. Spatially resolved Halpha kinematics (Herenz+, 2016)
J/A+A/644/A10 : LARS XI. Turbulence Driven Lyman Alpha Escape (Puschnig+, 2020)
J/ApJS/266/15 : The Lyα Reference Sample (LARS). XIV. (Melinder+, 2023)
Byte-by-byte Description of file: vfitmaps.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 9 F9.5 deg RAdeg Right Ascension of center (J2000)
10- 18 F9.5 deg DEdeg Declination of center (J2000)
20- 21 I2 --- Nx Number of pixels along X-axis
23- 24 I2 --- Ny Number of pixels along Y-axis
26 I1 Kibyte size Size of FITS file
28- 58 A31 --- FileName Name of FITS file, in vfit_fits subdirectory
60- 81 A22 --- Title Title of the FITS file
--------------------------------------------------------------------------------
Byte-by-byte Description of file: cubes.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 2 I2 h RAh Right Ascension of center (J2000)
4- 5 I2 min RAm Right Ascension of center (J2000)
7- 10 F4.1 s RAs Right Ascension of center (J2000)
11 A1 --- DE- Declination sign of center (J2000)
12- 13 I2 deg DEd Declination of center (J2000)
15- 16 I2 arcmin DEm Declination of center (J2000)
18- 21 F4.1 arcsec DEs Declination of center (J2000)
23- 24 I2 --- Nx Number of pixels along X-axis
26- 27 I2 --- Ny Number of pixels along Y-axis
29- 32 I4 --- Nz Number of pixels along Z-axis
34- 52 A19 "datime" Obs.date Observation date
54- 60 F7.2 0.1nm bAWAV Lower value of wavelength interval
62- 68 F7.2 0.1nm BAWAV Upper value of wavelength interval
70- 77 F8.6 0.1nm dAWAV Wavelength resolution
79- 83 I5 Kibyte size Size of FITS file
85-125 A41 --- FileName Name of FITS file, in cubes subdirectory
127-234 A108 --- Title Title of the FITS file
--------------------------------------------------------------------------------
Acknowledgements:
Edmund Christian Herenz, edmund.herenz(at)iucaa.in
References:
Hayes et al. Paper I. 2013ApJ...765L..27H 2013ApJ...765L..27H
Hayes et al. Paper II. 2014ApJ...782....6H 2014ApJ...782....6H
Pardy et al. Paper III. 2014ApJ...794..101P 2014ApJ...794..101P
Guaita et al. Paper IV. 2015A&A...576A..51G 2015A&A...576A..51G
Rivera-Thorsen et al. Paper V. 2015ApJ...805...14R 2015ApJ...805...14R
Duval et al. Paper VI. 2016A&A...587A..77D 2016A&A...587A..77D
Herenz et al. Paper VII. 2016A&A...587A..78H 2016A&A...587A..78H
Bridge et al. Paper VIII. 2018ApJ...852....9B 2018ApJ...852....9B
Micheva et al. Paper IX. 2018A&A...615A..46M 2018A&A...615A..46M
Runnholm et al. Paper X. 2020ApJ...892...48R 2020ApJ...892...48R
Puschnig et al. Paper XI. 2020A&A...644A..10P 2020A&A...644A..10P Cat. J/A+A/644/A10
Rasekh et al. Paper XII. 2022A&A...662A..64R 2022A&A...662A..64R
Melinder et al. Paper XIV. 2023ApJS..266...15M 2023ApJS..266...15M Cat. J/ApJS/266/15
(End) Patricia Vannier [CDS] 17-Oct-2024