J/A+A/694/A100 Spectral properties of 468 LAEs MUSE observations (Vitte+, 2025)
The MUSE eXtremely Deep Field.
Classifying the spectral shapes of Lyα-emitting galaxies.
Vitte E., Verhamme A., Hibon P., Leclercq F., Alcalde Pampliega B.,
Kerutt J., Kusakabe H., Matthee J., Guo Y., Bacon R., Maseda M.,
Richard J., Pharo J., Schaye J., Boogaard L., Nanayakkara T., Contini T.
<Astron. Astrophys. 694, A100 (2025)>
=2025A&A...694A.100V 2025A&A...694A.100V (SIMBAD/NED BibCode)
ADC_Keywords: Galaxy catalogs ; Redshifts ; Spectroscopy
Keywords: galaxies: evolution - galaxies: formation - galaxies: high-redshift -
cosmology: observations
Abstract:
The hydrogen Lyman-alpha (Lyα) line, the brightest rest-frame
ultraviolet line of high-redshift galaxies, exhibits a large variety
of shapes, which is due to factors at different scales, from the
interstellar medium to the intergalactic medium (IGM).
The aim of this work is to provide a systematic inventory and
classification of the spectral shapes of Lyα emission lines to
better understand the general population of high-redshift Lya emitting
galaxies (LAEs). Using the unprecedentedly deep data from the MUSE
eXtremely Deep Field (MXDF; up to 140 hour exposure time), we selected
477 galaxies observed in the ∼2.8-6.6 redshift range, 15 of which have
a systemic redshift from nebular lines. We developed a method to
classify Lyα emission lines in four spectral and three spatial
categories by combining a pure spectral analysis with a narrow-band
image analysis. We measured spectral properties, such as the peak
separation and the blue-to-total flux ratio for the double-peaked
galaxies.
To ensure a robust sample for statistical analysis, we define two
unbiased subsets, inclusive and restrictive, by applying thresholds
for signal-to-noise ratio, peak separation, and Lyα luminosity,
yielding a final unbiased sample of 206 galaxies. Our analysis reveals
that between 32% and 51% of the galaxies exhibit double-peaked
profiles, with peak separations ranging from 150km/s to nearly
1600km/s. The fraction of separations ranging from 150km/s to nearly
1600km/s. The fraction of double-peaked galaxies seems to evolve
dependently with the Lyα luminosity, while we do not see a severe
decrease in this fraction with redshift, which is expected given the
IGM attenuation at high redshift. An artificial increase in the number
of double-peaked galaxies at the highest redshifts may cause the
observation of a plateau instead of a decrease. A notable number of
these double-peaked profiles show blue-dominated spectra, suggesting
unique gas dynamics and inflow characteristics in some high-redshift
galaxies. The consequent fraction of blue-dominated spectra needs to
be confirmed by obtaining new systemic redshift measurements. Among
the double-peaked galaxies, 4% are spurious detections, that is, the
blue and red peaks do not come from the same spatial location. Around
20% out of the 477 sources of the parent sample lie in a complex
environment, meaning there are other clumps or galaxies at the same
redshift within a distance of 30kpc.
Our results suggest that the double-peaked LAE fraction may trace the
evolution of IGM attenuation, but the faintest galaxies must be
observed at high redshift. We also need more data to confirm the trend
seen at low redshift. In addition, it is crucial to obtain secure
systemic redshifts for LAEs to better constrain the nature of the
Lyα double-peaked lines. Statistical samples of double-peaked
and triple-peaked galaxies are a promising probe of the evolution of
the physical properties of galaxies across cosmic time.
Description:
We present the spectral properties of the LAEs analysed in our study.
The galaxies were observed in the MXDF by VLT/MUSE. The spectral
parameters were determined by the characterisation method.
Researchers using this catalogue should cite our associated
publication: Vitte E., Verhamme A., Hibon P. et al. 2024 'The MUSE
eXtremely Deep Field: Classifying the spectral shapes of Lya-emitting
galaxies.'
For any questions or additional information, please contact Eloise
Vitte at eloise.vitte(at)gmail.com.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
tablec1.dat 212 198 Single-peaked LAEs catalogue
tablec2.dat 349 248 Double-peaked LAEs catalogue
tablec3.dat 276 22 Triple-peaked LAEs catalogue
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See also:
J/A+A/670/A4 : MUSE Hubble Ultra Deep Field surveys. DR2 (Bacon+, 2023)
Byte-by-byte Description of file: tablec1.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 4 I4 --- ID MUSE identification number (G1)
6- 21 F16.14 --- zspec Spectroscopic redshift (G1)
23- 38 F16.13 deg RAdeg Right Ascension (J2000)
40- 56 F17.13 deg DEdeg Declination (J2000)
58 I1 --- Npeaks Number of spectral peaks of the Lyα
line (G2)
60 A1 --- Cat [BGS] Spatial category (G3)
62- 72 A11 --- CID Pair or triplet corresponding ID (G4)
74- 94 F21.16 10-23W/m2 FLya Total flux Lyα line
96-114 F19.16 10-23W/m2 e_FLya Total flux Lyα line error
116-129 E14.8 10-7W LLya Lya luminosity
131-152 E22.16 10-7W e_LLya Lya luminosity error
154-172 F19.16 --- SNR Signal-to-noise ratio
174-191 F18.14 km/s FWHM FWHM of Lya peak
193-212 F20.16 km/s e_FWHM FWHM of Lya peak error
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Byte-by-byte Description of file: tablec2.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 4 I4 --- ID MUSE identification number (G1)
6- 21 F16.14 --- zspec Spectroscopic redshift (G1)
23- 38 F16.13 deg RAdeg Right Ascension (J2000)
40- 56 F17.13 deg DEdeg Declination (J2000)
58 I1 --- Npeaks Number of spectral peaks of the
Lyα line (G2)
60 A1 --- Cat [BGS] Spatial category (G3)
62- 73 A12 --- CID Pair or triplet corresponding ID (G4)
75- 94 F20.15 10-23W/m2 FLya Total flux Lyα line
96-115 F20.16 10-23W/m2 e_FLya Total flux Lyα line error
117-130 E14.8 10-7W LLya Lyα luminosity
133-156 E24.16 10-7W e_LLya Lyα luminosity error
157-176 F20.16 --- SNR Signal-to-noise ratio
178-195 F18.14 km/s FWHM1 FWHM of peak 1 (left peak)
197-215 F19.15 km/s e_FWHM1 FWHM of peak 1 error
217-234 F18.14 km/s FWHM2 FWHM of peak 2 (right peak)
237-260 E24.16 km/s e_FWHM2 FWHM of peak 2 error
261-280 F20.18 --- BT Blue-to-total flux ratio
282-304 F23.19 --- e_BT Blue-to-total flux ratio error
306-324 F19.14 km/s vsep Peak separation
326-349 E24.16 km/s e_vsep Peak separation error
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Byte-by-byte Description of file: tablec3.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 4 I4 --- ID MUSE identification number (G1)
6- 21 F16.14 --- zspec Spectroscopic redshift (G1)
23- 38 F16.13 deg RAdeg Right Ascension J2000
40- 56 F17.13 deg DEdeg Declination J2000
58 I1 --- Npeaks Number of spectral peaks of the
Lyα line (G2)
60 A1 --- Cat [BGS] Spatial category (G3)
62 A1 --- CID [0] Corresponding ID (G4)
64- 82 F19.14 10-23W/m2 FLya Total flux Lyα line
84-101 F18.15 10-23W/m2 e_FLya Total flux Lyα line error
103-116 E14.8 10-7W LLya Lyα luminosity
118-139 E22.16 10-7W e_LLya Lyα luminosity error
141-160 F20.16 --- SNR Signal-to-noise ratio
162-179 F18.14 km/s FWHM1 FWHM of peak 1 (left peak)
181-199 F19.15 km/s e_FWHM1 FWHM of peak 1 error
201-218 F18.14 km/s FWHM2 FWHM of peak 2 (middle peak)
220-237 F18.15 km/s e_FWHM2 FWHM of peak 2 error
239-256 F18.14 km/s FWHM3 FWHM of peak 3 (right peak)
258-276 F19.15 km/s e_FWHM3 FWHM of peak 3 error
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Global notes:
Note (G1): From Bacon et al., 2023A&A...670A...4B 2023A&A...670A...4B, Cat. J/A+A/670/A4
Note (G2): Number of spectral peaks of the Lyα line as follows:
1 = single-peak
2 = double-peak
3 = triple-peak
Note (G3): Spatial category as follows:
G = GOLD
S = SILVER
B = BRONZE
Note (G4): 0 = the galaxy do not belong to a pair or a triplet system
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Acknowledgements:
Eloise Vitte, eloise.vitte(at)gmail.com
References:
Bacon et al., 2023A&A...670A...4B 2023A&A...670A...4B, Cat. J/A+A/670/A4
The MUSE Hubble Ultra Deep Field surveys: Data release II
(End) Patricia Vannier [CDS] 31-Dec-2024