J/ApJ/863/92 LAE cand. at z∼5.7 in the field of QSO J0148+0600 (Becker+, 2018)
Evidence for large-scale fluctuations in the metagalactic ionizing background
near redshift six.
Becker G.D., Davies F.B., Furlanetto S.R., Malkan M.A., Boera E.,
Douglass C.
<Astrophys. J., 863, 92 (2018)>
=2018ApJ...863...92B 2018ApJ...863...92B
ADC_Keywords: Galaxies, photometry; Intergalactic medium; Optical
Keywords: dark ages, reionization, first stars ; galaxies: high-redshift ;
intergalactic medium ; quasars: absorption lines
Abstract:
The observed scatter in intergalactic Lyα opacity at z≲6
requires large-scale fluctuations in the neutral fraction of the
intergalactic medium (IGM) after the expected end of reionization.
Post-reionization models that explain this scatter invoke fluctuations
in either the ionizing ultraviolet background (UVB) or IGM
temperature. These models make very different predictions, however,
for the relationship between Lyα opacity and local density.
Here, we test these models using Lyα-emitting galaxies (LAEs) to
trace the density field surrounding the longest and most opaque known
Lyα trough at z<6. Using deep Subaru Hyper Suprime-Cam
narrowband imaging, we find a highly significant deficit of z∼5.7 LAEs
within 20h-1Mpc of the trough. The results are consistent with a
model in which the scatter in Lyα opacity near z∼6 is driven by
large-scale UVB fluctuations, and disfavor a scenario in which the
scatter is primarily driven by variations in IGM temperature. UVB
fluctuations at this epoch present a boundary condition for
reionization models, and may help shed light on the nature of the
ionizing sources.
Description:
We acquired deep Subaru Hyper Suprime-Cam (HSC) imaging of the field
around QSO J0148+0600 from 2016 September and 2017 August, with the
majority of data obtained in 2017. Imaging was performed in the r2,
i2, and NB816 filters in dithered exposures centered on the quasar
position.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table2.dat 103 806 Properties of Lyα-emitting galaxy (LAE)
candidates
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See also:
J/ApJS/176/301 : Subaru/XMM-Newton deep survey IV. (SXDS) (Ouchi+, 2008)
J/ApJ/793/115 : UV-continuum slopes beta for z∼4-8 galaxies (Bouwens+, 2014)
J/MNRAS/442/946 : z∼5.7 C IV absorption systems (Diaz+, 2014)
J/MNRAS/445/1745 : Giant Gemini GMOS survey. I. (Worseck+, 2014)
J/ApJ/803/34 : z∼4-10 galaxies from HST legacy fields (Bouwens+, 2015)
J/MNRAS/449/4204 : WFC3/UVIS quasar-stacked spectrum at z≃2.4 (Lusso+, 2015)
J/AJ/155/131 : z∼5 QSO luminosity function from the CFHTLS (McGreer+, 2018)
J/PASJ/70/S10 : GOLDRUSH I. UV magnitudes (Ono+, 2018)
Byte-by-byte Description of file: table2.dat
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Bytes Format Units Label Explanations
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1- 14 A14 --- ID LAE identifier (JHHMMSS+DDMMSS);
<[BDF2018] JHHMMSS+DDMMSS> in Simbad
16- 17 I2 h RAh [1] Hour of Right Ascension (J2000)
19- 20 I2 min RAm [45/51] Minute of Right Ascension (J2000)
22- 27 F6.3 s RAs Second of Right Ascension (J2000)
29- 29 A1 --- DE- [+] Sign of the Declination (J2000)
30- 31 I2 deg DEd [5/6] Degree of Declination (J2000)
33- 34 I2 arcmin DEm Arcminute of Declination (J2000)
36- 40 F5.2 arcsec DEs Arcsecond of Declination (J2000)
42- 46 F5.2 mag NB816 [21.7/26] NB816 magnitude, AB mag (1)
48- 53 F6.3 cW/m2/nm Fr2 [-0.2/0.5] r2 flux, erg/s/cm2/Å
55- 59 F5.3 cW/m2/nm e_Fr2 [0.006/0.04] r2 flux error
61- 66 F6.3 cW/m2/nm Fi2 [-0.06/1.1] i2 flux, erg/s/cm2/Å
68- 72 F5.3 cW/m2/nm e_Fi2 [0.01/0.05] i2 flux error
74- 78 F5.3 cW/m2/nm FNB816 [0.1/7.2] NB816 flux, erg/s/cm2/Å (1)
80- 84 F5.3 cW/m2/nm e_FNB816 [0.01/0.1] NB816 flux error
86- 91 F6.3 [10-7W] logLya [42.4/44.2] log Lyα luminosity,
in erg/s units (2)
93- 97 F5.3 [10-7W] E_logLya [0.002/0.1] log Lyα luminosity,
upper error
99-103 F5.3 [10-7W] e_logLya [0.002/0.08] log Lyα luminosity,
lower error
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Note (1): The NB816 filter has a transmission-weighted mean wavelength of
λ=8177Å, corresponding to Lyα at z=5.726, and ≥50%
peak transmission over 8122Å<λ<8239Å, corresponding to
5.681<z<5.777.
Note (2): Lyα luminosities were computed by multiplying the observed
NB816 flux by 4πDL**2 , where DL is the luminosity distance at z=5.726.
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History:
From electronic version of the journal
(End) Prepared by [AAS], Emmanuelle Perret [CDS] 06-Aug-2019