J/A+A/693/A253 The Lyα Reference Sample (LARS). XVI. (Le Reste+, 2025)
The Lyman Alpha Reference Sample.
XVI. Global 21 cm Hi properties of Lyman-alpha emitting galaxies.
Le Reste A., Hayes M.J., Cannon J.M., Melinder J., Runnholm A.,
Rivera-Thorsen T. E., Ostlin G., Adamo A., Herenz E.C., Schaerer D.,
Scarlata C., Kunth D.
<Astron. Astrophys. 693, A253 (2025)>
=2025A&A...693A.253L 2025A&A...693A.253L (SIMBAD/NED BibCode)
ADC_Keywords: Galaxies, radio ; H I data ; Ultraviolet
Keywords: ISM: lines and bands - galaxies: interactions - galaxies: ISM -
galaxies: starburst - radio lines: galaxies
Abstract:
The Lyman-alpha (Lyα) line of hydrogen is a well-known tracer of
galaxies at high redshift. However, the connection between Lyα
observables and galaxy properties has not been fully established,
limiting the use of the line to probe the physics of galaxies. Here,
we derive the global neutral hydrogen gas (HI) properties of nearby
Lyα-emitting galaxies to assess the impact of neutral gas on the
Lyα output of galaxies. We observed the 21cm line emission using
the Karl G. Jansky Very Large Array in D-array configuration (∼55"
resolution, ∼38kpc) for 37 star-forming galaxies with available Hubble
Space Telescope (HST) Lyα imaging from the Lyman Alpha Reference
Samples. We detected 21 cm emission for 33 out of the 37 galaxies
observed. We found no significant correlation of global HI properties
(including HI mass, column density, gas fraction, depletion time, line
width, or velocity shift between HI and Lyα), with the Lyα
luminosity, escape fractions, or equivalent widths (EW) derived with
HST photometry. Additionally, both Lyα-emitters and weak or
non-emitters are distributed evenly along the HI parameter space of
optically selected z=0 galaxies. Around 74% of the sample is
undergoing galaxy interaction, this fraction is higher for
Lyα-emitters (83% for galaxies with EW≥20Å) than for weak or
non-emitters (70%). Nevertheless, galaxies identified as interacting
have Lyα and HI properties statistically consistent with those
of non-interacting galaxies. Our results show that global HI
properties (on scales >30kpc) have little direct impact on the
Lyα output from galaxies. Instead, HI likely regulates Lyα
emission on small scales: statistical comparisons of Lyα and
high angular resolution 21cm observations are required to fully assess
the role of HI in Lyα radiative transfer. While our study
indicates that major and minor galaxy mergers could play a role in the
emission of Lyα photons in the local Universe, especially for
galaxies with high HI fractions, the line of sight that a system is
observed through ultimately determines the Lyα observables.
Description:
The tables included here contain parameters related to the VLA 21cm
line observations of Lyα-emitting galaxies in the LARS and eLARS
galaxy samples. They include 21cm line properties, general galaxy
properties, some Lyα line observables, as well as VLA observation
parameters and flags related to the visual identification of galaxies
in the sample undergoing gravitational interaction. Throughout this
paper we use a {LAMBDA}CDM cosmology with (H0, {OMEGA}m,
{OMEGA}{LAMBDA})=(70km/s/Mpc, 0.3, 0.7).
File Summary:
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FileName Lrecl Records Explanations
--------------------------------------------------------------------------------
ReadMe 80 . This file
table1.dat 17 42 Merger identification flags
tablea1.dat 63 42 VLA observation parameters
tablea2.dat 221 42 General galaxy and Lyα properties
tablea3.dat 481 42 21cm line properties
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See also:
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: table1.dat
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Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 7 A7 --- ID Sample Identifier used in this work,
LRASNN or eLARSNN (ID)
9 I1 --- int [0/1] Interaction flag (1=int, 0=no int)
(int)
11 I1 --- closepair [0/1] Close pair interaction flag (closepair)
13 I1 --- intMorphOpt [0/1] Optical morphology interaction flag
(intmorphopt)
15 I1 --- intMorphHI [0/1]?=- HI morphology interaction flag
(intmorphhi)
17 I1 --- intHaKin [0/1] Hα kinematics interaction flag
(inthakin)
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Byte-by-byte Description of file: tablea1.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 7 A7 --- ID Sample Identifier used in this work (ID)
9- 13 F5.2 h Tobs ?=- Integration time (t_obs)
15- 19 F5.2 --- pflag ?=- Percentage of flagged visibilities (p_flag)
21- 25 A5 --- bpcal Bandpass calibrator (bp_cal)
27- 36 A10 --- phcal Phase calibrator (ph_cal)
38- 43 F6.3 arcsec bmin ?=- Beam minor axis (bmin)
45- 50 F6.3 arcsec bmaj ?=- Beam major axis (bmaj)
52- 58 F7.3 deg PA []?=- Beam position angle (pa)
60- 63 F4.2 mJy rms ?=- VLA cube RMS (rms)
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Byte-by-byte Description of file: tablea2.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 7 A7 --- ID Sample Identifier used in this work (ID)
9- 24 F16.12 deg RAdeg Right Ascension J2000 (RA)
26- 41 F16.13 deg DEdeg Declination J2000 (DEC)
43- 62 F20.18 --- z Redshift (z)
64- 81 F18.14 Mpc D Luminosity distance (D)
83-104 E22.16 Msun MGSWLC Stellar mass (from GSWLC) (M_GSWLC)
106-128 E23.16 Msun e_MGSWLC Stellar mass error (from GSWLC) (M_GSWLCe)
130-149 F20.17 Msun/yr SFRGSWLC Star formation rate (from GSWLC) (SFR_GSWLC)
151-170 F20.18 Msun/yr e_SFRGSWLC Star formation rate error (from GSWLC)
(SFR_GSWLCe)
172-179 F8.4 km/s DvLyared ?=- Lyα red peak offset velocity
(from systemic) (DvLyared)
181-199 F19.16 km/s b_DvLyared Lyα red peak offset velocity
lower bound error (DvLyaredl)
201-219 F19.16 km/s B_DvLyared Lyα red peak offset velocity
upper bound error (DvLyaredu)
221 A1 --- Note [a] a = GSWLC values predicted from fit to
SDSS data (note)
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Byte-by-byte Description of file: tablea3.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 7 A7 --- ID Sample Identifier used in this work (ID)
9- 26 F18.12 km/s vHIb ?=- 21cm line centroid velocity
(beam extraction) (vHIb)
28- 45 F18.16 km/s e_vHIb ?=- 21cm line centroid velocity error
(beam extraction) (vHIbe)
47- 66 F20.18 --- zHIb ?=- 21cm line centroid redshift
(beam extraction) (zHIb)
68- 89 E22.16 --- e_zHIb ?=- 21cm line centroid redshift error
(beam extraction) (zHIbe)
91-109 F19.17 Jy.km/s SHIb ?=- 21cm line flux density
(beam extraction) (SHIb)
111-130 F20.18 Jy.km/s e_SHIb ?=0 21cm line flux density error
(beam extraction) (SHIbe)
132-153 E22.16 Msun MHIb ?=- HI mass (beam extraction) (MHIb)
155-178 E24.16 Msun e_MHIb ?=0 HI mass error (beam extraction) (MHIbe)
180-202 E23.16 cm-2 NHIb ?=- HI column density (beam extraction)
(NHIb)
203-226 E24.17 cm-2 e_NHIb ?=- HI column density error (beam extraction)
(NHIbe)
227-244 F18.14 km/s W50HIb ?=- HI line width (beam extraction) (W50HIb)
246-263 F18.12 km/s vHIt ?=- 21cm line centroid velocity
(total extraction) (vHIt)
265-282 F18.16 km/s e_vHIt ?=- 21cm line centroid velocity error
(total extraction) (vHIte)
284-303 F20.18 --- zHIt ?=- 21cm line centroid redshift
(total extraction) (zHIt)
305-326 E22.16 --- e_zHIt ?=- 21cm line centroid redshift error
(total extraction) (zHIte)
328-346 F19.17 Jy.km/s SHIt ?=- 21cm line flux density (total extraction)
(SHIt)
348-367 F20.18 Jy.km/s e_SHIt ?=0 21cm line flux density error
(total extraction) (SHIte)
369-390 E22.16 Msun MHIt ?=- HI mass (total extraction) (MHIt)
393-415 E23.16 Msun e_MHIt ?=0 HI mass error (total extraction) (MHIte)
417-438 E22.16 cm-2 NHIt ?=- HI column density (total extraction)
(NHIt)
440-462 E23.17 cm-2 e_NHIt ?=- HI column density error (total extraction)
(NHIte)
464-481 F18.14 km/s W50HIt ?=- HI line width (total extraction)
(W50HIt)
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Acknowledgements:
Alexandra Le Reste, alereste(at)umn.edu
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] 16-Dec-2024