J/MNRAS/472/772 Candidate LAEs at z=5.7 and z=6.6 (Matthee+, 2017)
Spectroscopic properties of luminous Ly α emitters at z ~= 6-7 and
comparison to the Lyman-break population.
Matthee J., Sobral D., Darvish B., Santos S., Mobasher B.,
Paulino-afonso A., Rottgering H., Alegre L.
<Mon. Not. R. Astron. Soc., 472, 772-787 (2017)>
=2017MNRAS.472..772M 2017MNRAS.472..772M (SIMBAD/NED BibCode)
ADC_Keywords: Galaxies, spectra ; Redshifts ; Equivalent widths ;Ultraviolet
Keywords: galaxies: evolution - galaxies: high-redshift
dark ages, reionization, first stars - cosmology: observations
Abstract:
We present spectroscopic follow-up of candidate luminous Lyα
emitters (LAEs) at z=5.7-6.6 in the SA22 field with VLT/X-SHOOTER. We
confirm two new luminous LAEs at z=5.676 (SR6) and z=6.532 (VR7),
and also present HST follow-up of both sources. These sources have
luminosities L_Ly α_~=3x1043erg/s, very high rest-frame
equivalent widths of EW0≥200Å and narrow Lyα lines
(200-340km/s). VR7 is the most UV-luminous LAE at z>6.5, with
M1500=-22.5, even brighter in the UV than CR7. Besides Lyα, we
do not detect any other rest-frame UV lines in the spectra of SR6 and
VR7, and argue that rest-frame UV lines are easier to observe in
bright galaxies with low Lyα equivalent widths. We confirm that
Lyα line widths increase with Lyα luminosity at z=5.7,
while there are indications that Lyα lines of faint LAEs become
broader at z=6.6, potentially due to reionization. We find a large
spread of up to 3 dex in UV luminosity for >L* LAEs, but find that the
Lyα luminosity of the brightest LAEs is strongly related to UV
luminosity at z=6.6. Under basic assumptions, we find that several
LAEs at z~=6-7 have Lyα escape fractions ≥100 per cent,
indicating bursty star formation histories, alternative Lyα
production mechanisms, or dust attenuating Lyα emission
differently than UV emission. Finally, we present a method to compute
ξion, the production efficiency of ionizing photons, and find
that LAEs at z~=6-7 have high values of
log10(ξion/Hz/erg)~=25.51±0.09 that may alleviate the need
for high Lyman-Continuum escape fractions required for reionization.
Description:
The target sample includes candidate luminous LAEs selected through
NB816 and NB921 narrow-band imaging with Subaru/Suprime-Cam in the
SA22 field over comoving volumes of 6.3x106Mpc3 and
4.3x106Mpc3 at z=5.7 and z=6.6 as described in Santos et al.
(2016MNRAS.463.1678S 2016MNRAS.463.1678S) and Matthee et al. (2015MNRAS.451..400M 2015MNRAS.451..400M),
respectively.
We observed the candidate LAEs with the X-SHOOTER echelle
spectrograph, mounted on UT2 of the VLT. X-SHOOTER simultaneously
takes a high-resolution spectrum with a UVB, VIS and a NIR arm,
providing a wavelength coverage from 300 to 2480nm.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
tableb1.dat 104 486 Candidate LAEs at z=5.7 from Santos et al.
(2016MNRAS.463.1678S 2016MNRAS.463.1678S)
tableb2.dat 96 115 Candidate LAEs at z=6.6 from Matthee et al.
(2015MNRAS.451..400M 2015MNRAS.451..400M)
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See also:
J/A+A/498/13 : Lyman-α emitters from redshifts z∼2-3 (Nilsson+, 2009)
J/A+A/628/A3 : LAE z∼3-7 luminosity functions (de La Vieuville+, 2019)
J/ApJ/706/762 : LAEs at z∼4.5 in the LALA Cetus field (Wang+, 2009)
J/MNRAS/403/L54 : Lyα emitters (LAE) in A1689-7.1 (Matsuda+, 2010)
J/ApJ/736/31 : HETDEX pilot survey. II. 1.9<z<3.8 LAEs (Blanc+, 2011)
J/ApJ/738/136 : LAEs between 0.19<z<1.25 with GALEX grism (Cowie+, 2011)
J/ApJ/743/9 : z=3.1 LAEs morphological properties (Gronwall+, 2011)
J/ApJ/744/110 : LAE galaxies between 2.1=<z≤3.1 (Ciardullo+, 2012)
J/ApJ/751/29 : Lyα profiles of LAEs at z=3.1 (Yamada+, 2012)
J/ApJ/753/95 : LAE galaxies in the ECDF-S at z∼2.1 and z∼3.1 (Bond+, 2012)
J/ApJ/765/47 : Lyman-break galaxies and LAEs at z∼3 (Nestor+, 2013)
J/ApJ/779/65 : Photometry of LBGs, LAEs & GNBs at z∼2.85 (Mostardi+, 2013)
J/ApJ/810/107 : Lyman break galaxies & LAEs HST photometry (Mostardi+, 2015)
J/ApJ/813/78 : Spitzer z=4.5 & z=5.7 LAEs properties (Finkelstein+, 2015)
J/ApJ/845/172 : LAE candidates around bright Lyα blobs (Badescu+ 2017)
J/MNRAS/465/316 : Lyman continuum LAEs and LBGs in SSA22 field (Micheva+ 2017(
J/MNRAS/468/1123 : LAE among star-forming galaxies at z=2.5 (Shimakawa+, 2017)
J/ApJ/863/92 : LAE cand. at z∼5.7 in QSO J0148+0600 field (Becker+, 2018)
Byte-by-byte Description of file: tableb1.dat
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Bytes Format Units Label Explanations
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1- 25 A25 --- Name Name, IDNB1
27- 28 I2 h RAh Right ascension (J2000)
30- 31 I2 min RAm Right ascension (J2000)
33- 38 F6.3 s RAs Right ascension (J2000)
40 A1 --- DE- Declination sign (J2000)
41- 42 I2 deg DEd Declination (J2000)
44- 45 I2 arcmin DEm Declination (J2000)
47- 52 F6.3 arcsec DEs Declination (J2000)
54- 58 F5.1 10-20W/m2 FNB816 NB816 line flux
60- 64 F5.1 --- LLya Lymanα luminosity
66- 68 I3 0.1nm EW0 Equivalent width
70 A1 --- l_EW0 [0/1] Limit flag on EW0
72- 90 A19 --- BibCode Reference bibcode
92-104 A13 --- Aut Author's name
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Byte-by-byte Description of file: tableb2.dat
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Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 19 A19 --- Name Name
21- 22 I2 h RAh Right ascension (J2000)
24- 25 I2 min RAm Right ascension (J2000)
27- 32 F6.3 s RAs Right ascension (J2000)
34 A1 --- DE- Declination sign (J2000)
35- 36 I2 deg DEd Declination (J2000)
38- 39 I2 arcmin DEm Declination (J2000)
41- 46 F6.3 arcsec DEs Declination (J2000)
48- 50 F3.1 10-20W/m2 FNB921 NB921 line flux
52- 55 F4.1 --- LLya Lyα luminosity
57- 59 I3 0.1nm EW0 Equivalent width
61 A1 --- l_EW0 [0/1] Limt flag on EW0
63- 81 A19 --- BibCode Reference bibcode
83- 96 A14 --- Aut Author's name
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History:
From electronic version of the journal
(End) Patricia Vannier [CDS] 17-Jun-2020