J/A+A/659/A183 MUSE-Wide+MUSE-Deep EWs of Lymanα emitters (Kerutt+, 2022)
Equivalent widths of Lymanα emitters in MUSE-Wide and MUSE-Deep.
Kerutt J., Wisotzki L., Verhamme A., Schmidt K.B., Leclercq F., Herenz E.C.,
Urrutia T., Garel T., Hashimoto T., Maseda M., Matthee J., Kusakabe H.,
Schaye J., Richard J., Guiderdoni B., Mauerhofer V., Nanayakkara T.,
Vitte E.
<Astron. Astrophys. 659, A183 (2022)>
=2022A&A...659A.183K 2022A&A...659A.183K (SIMBAD/NED BibCode)
ADC_Keywords: Galaxy catalogs ; Ultraviolet ; Spectroscopy
Keywords: galaxies: high redshift - galaxies: formation -
galaxies: evolution - cosmology: observations
Abstract:
The hydrogen Lymanα line is often the only measurable feature in
optical spectra of high-redshift galaxies. Its shape and strength are
influenced by radiative transfer processes and the properties of the
underlying stellar population. High equivalent widths of several
hundred Å are especially hard to explain by models and could point
towards unusual stellar populations, for example with low
metallicities, young stellar ages, and a top-heavy initial mass
function. Other aspects influencing equivalent widths are the
morphology of the galaxy and its gas properties.
The aim of this study is to better understand the connection between
the Lymanα rest-frame equivalent width (EW0) and spectral
properties as well as ultraviolet (UV) continuum morphology by
obtaining reliable EW0 histograms for a statistical sample of galaxies
and by assessing the fraction of objects with large equivalent widths.
We used integral field spectroscopy from the Multi Unit Spectroscopic
Explorer (MUSE) combined with broad-band data from the Hubble Space
Telescope (HST) to measure EW0 . We analysed the emission lines of
1920 Lymanα emitters (LAEs) detected in the full MUSE-Wide (one
hour exposure time) and MUSE-Deep (ten hour exposure time) surveys and
found UV continuum counterparts in archival HST data. We fitted the UV
continuum photometric images using the Galfit software to gain
morphological information on the rest-UV emission and fitted the
spectra obtained from MUSE to determine the double peak fraction,
asymmetry, full-width at half maximum, and flux of the Lymanα
line.
The two surveys show different histograms of Lymanα EW0 . In
MUSE-Wide, 20% of objects have EW0>240Å, while this fraction is
only 11% in MUSE-Deep and ~=16% for the full sample. This includes
objects without HST continuum counterparts (one-third of our sample),
for which we give lower limits for EW0. The object with the highest
securely measured EW0 has EW0=589±193Å (the highest lower limit
being EW0=4464Å). We investigate the connection between EW0 and
Lymanα spectral or UV continuum morphological properties.
The survey depth has to be taken into account when studying EW0
distributions. We find that in general, high EW0 objects can have a
wide range of spectral and UV morphological properties, which might
reflect that the underlying causes for high EW0 values are equally
varied.
Description:
The catalogs contains measurements of properties of 1920 LAEs in the
MUSE-Wide and MUSE-deep fields. The content of the catalog is
described throughout the paper and in particular in Appendix B.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
tableb1.dat 171 1920 Catalog
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See also:
J/A+A/608/A2 : MUSE Hubble Ultra Deep Field Survey. II. (Inami+, 2017)
J/A+A/621/A107 : MUSE-Wide Lyman alpha luminosity function 3<z<6 (Herenz+ 2019)
J/A+A/624/A141 : MUSE-Wide Survey DR1 catalog (Urrutia+, 2019)
Byte-by-byte Description of file: tableb1.dat
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Bytes Format Units Label Explanations
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1- 9 I9 --- ID Unique MUSE-Wide object ID (1)
11- 14 I4 --- I17ID ?=0 Source identifier in Inami et al., 2017,
Cat. J/A+A/608/A2,
[IBB2017] NNNN in Simbad (2)
16- 24 F9.5 deg RAdeg Right Ascension (J2000) of UV continuum
26- 34 F9.5 deg DEdeg Declination (J2000) of UV continuum
36- 41 F6.4 --- z Redshift of the source based on Lya
43- 50 F8.4 --- e_z Uncertainty on the redshift
52 I1 --- Conf [0/3] Confidence level from QtClassify as
in Urrutia et al., 2019A&A...624A.141U 2019A&A...624A.141U (3)
54- 60 F7.2 0.1nm EW0 Rest-frame equivalent width of Ly alpha
62- 67 F6.2 0.1nm e_EW0 Uncertainty on EW0
69- 75 F7.3 mag MUV Estimated absolute UV magnitude (AB)
at 1500 Angstrom
77- 81 F5.3 mag e_MUV Uncertainty on MUV
83- 87 F5.2 [10-7W] logLLya log Ly alpha luminosity given in erg/s
89- 93 F5.2 [10-7W] e_logLLya Uncertainty on logLLya
95-101 F7.2 km/s Peaksep Peak separation of LAEs with a two-component
Ly alpha line
103-119 E17.9 km/s e_Peaksep Uncertainty on Peaksep
121-126 F6.2 km/s FWHM Full-width at half maximum of the Ly alpha
(red component) emission line
128-135 F8.2 km/s e_FWHM Uncertainty on FWHM
137-141 F5.2 --- Asym Asymmetry parameter of the asymmetric
Gaussian fit to the main red peak
143-147 F5.2 --- e_Asym Uncertainty of Asym
149-154 F6.2 kpc Re Effective radius in (physical) kpc measured
with Galfit
156-161 F6.2 kpc e_Re uncertainty on Re
163-166 F4.2 --- axisratio Morphological parameter of the UV continuum
counterpart, obtained using Galfit
168-171 F4.2 --- e_axisratio Uncertainty of axisratio
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Note (1): IDs are the same as in Urrutia et al., 2019, Cat. J/A+A/624/141 and
Herenz et al., 2017, Cat. J/A+A/621/107 for objects that are in their
sample as well.
Note (2): Set to 0 if the object is not in Inami et al. 2017, Cat. J/A+A/608/A2.
Note (3): Confidence flag as follows:
1 = lowest confidence with an assumed error probability in the
correct identification of the line of up to ~=50%.
2 = still quite trustful result (expected error rate ≤10%)
3 = very high certainty
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Acknowledgements:
Josephine Kerutt, Josephine.Kerutt(at)UniGe.ch
(End) Patricia Vannier [CDS] 17-Jan-2022