J/ApJ/933/87 F125W and UV mag of 6.0<z<8.2 galaxies candidates (Jung+, 2022)
CLEAR: Boosted Lyα transmission of the intergalactic medium in UV-bright
galaxies.
Jung I., Papovich C., Finkelstein S.L., Simons R.C., Estrada-Carpenter V.,
Backhaus B.E., Cleri N.J., Finlator K., Giavalisco M., Ji Z., Matharu J.,
Momcheva I., Straughn A.N., Trump J.R.
<Astrophys. J., 933, 87 (2022)>
=2022ApJ...933...87J 2022ApJ...933...87J
ADC_Keywords: Galaxies; Redshifts ; Spectra, infrared ; Ultraviolet ; Optical;
Magnitudes, absolute ; Photometry, HST; Equivalent widths; Surveys
Keywords: Reionization ; Early universe ; Intergalactic medium ; High-
redshift galaxies ; Lyman-alpha galaxies ; Extragalactic
astronomy
Abstract:
Reionization is an inhomogeneous process, thought to begin in small
ionized bubbles of the intergalactic medium (IGM) around overdense
regions of galaxies. Recent Lyα studies during the epoch of
reionization show evidence that ionized bubbles formed earlier around
brighter galaxies, suggesting higher IGM transmission of Lyα
from these galaxies. We investigate this problem using IR slitless
spectroscopy from the Hubble Space Telescope (HST) Wide-Field Camera 3
(WFC3) G102 grism observations of 148 galaxies selected via
photometric redshifts at 6.0<z<8.2. These galaxies have spectra
extracted from the CANDELS Lyα Emission at Reionization (CLEAR)
survey. We combine the CLEAR data for 275 galaxies with the Keck Deep
Imaging Multi-Object Spectrograph and MOSFIRE data set from the Texas
Spectroscopic Search for Lyα Emission at the End of Reionization
Survey. We constrain the Lyα equivalent width (EW) distribution
at 6.0<z<8.2, which is described by an exponential form,
dN/dEW∝exp(-EW)/W0, with the characteristic e-folding
scale width (W0). We confirm a significant drop in the Lyα
strength (i.e., W0) at z>6. Furthermore, we compare the redshift
evolution of W0 between galaxies at different UV luminosities.
UV-bright (MUV←21 [i.e., LUV>L*]) galaxies show weaker
evolution with a decrease of 0.4(±0.2) dex in W0 at z>6, while
UV-faint (MUV>-21 [LUV<L*]) galaxies exhibit a significant drop
of 0.7-0.8(±0.2) dex in W0 from z<6 to z>6. If the change in
W0 is proportional to the change in the IGM transmission for
Lyα photons, then this is evidence that the transmission is
"boosted" around UV-brighter galaxies, suggesting that reionization
proceeds faster in regions around such galaxies.
Description:
We extracted HST slitless grism spectra of 148 high-z galaxies in the
GOODS fields from the CANDELS Lyα Emission at Reionization (CLEAR)
survey. The CLEAR Experiment is a cycle 23 HST observing program
(Program GO-14227, PI: C. Papovich), which observed 12 fields in the
CANDELS GOODS fields to 10 to 12 orbit depth with the G102 grism in
the HST/WFC3 camera. Each field was observed at three position angles
(separated by >10 degrees) to properly correct galaxy spectra from
contamination.
The data set has been extended to include all publicly available
HST/WFC3 G102 and G141 grism observations in the CLEAR fields.
While the primary CLEAR spectral extractions were made for galaxies
based on the 3D-HST GOODS catalog, Skelton+ (2014, J/ApJS/214/24), we
extracted the CLEAR spectra of high-z galaxies based on the updated
HST CANDELS photometry and its segmentation maps from
Finkelstein+ (2022ApJ...928...52F 2022ApJ...928...52F). Visual inspection was performed
for removing any artifacts and checking the quality of photometry.
See Section 2.1.
We also used supplemental data from Keck DEIMOS and MOSFIRE observations.
See Section 2.3.
We utilized the HST ACS and WFC3 broadband photometry (B435, V606,
i775, I814, z850, Y105, J125, JH140, and H160) in addition to Spitzer
Infrared Array Camera (IRAC) 3.6um and 4.5um band fluxes to derive the
properties of our 148 sources. UV magnitudes of galaxies were
calculated from the averaged fluxes over a 100Å-bandpass (at
1450-1550Å) from the best-fit models, which were not dust-corrected.
In our SED fitting, we fixed redshifts with the best-fit photometric
redshifts calculated by EAZY.
See section 2.4.
In this work, we assume the Planck cosmology with H0=67.8km/s/Mpc,
ΩM=0.308, and ω_Λ=0.692. All magnitudes are given
in the AB system.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table2.dat 98 148 Summary of the CANDELS Lyα Emission at
Reionization (CLEAR) 6.0<z<8.2 targets
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See also:
VI/146 : Galaxies in the Cosmic Dawn II simulation (Ocvirk+, 2020)
J/ApJ/667/79 : Lyα emission-line galaxies at z=3.1 (Gronwall+, 2007)
J/ApJS/176/301 : Subaru/XMM-Newton deep survey IV. (SXDS) (Ouchi+, 2008)
J/A+A/498/13 : Lyman-α emitters from redshifts z∼2-3 (Nilsson+, 2009)
J/ApJ/711/928 : Low-redshift Lyα galaxies from GALEX (Cowie+, 2010)
J/ApJ/725/394 : High-redshift Lyα emitters (Hu+, 2010)
J/ApJ/744/110 : LAE galaxies between 2.1=<z≤3.1 (Ciardullo+, 2012)
J/ApJ/756/164 : UV galaxies in CANDELS from z=8 to z=4 (Finkelstein+, 2012)
J/ApJ/7/128 : Lya emission from 4<z<6 sources in COSMOS (Mallery+, 2012)
J/ApJS/214/24 : 3D-HST+CANDELS catalog (Skelton+, 2014)
J/ApJ/783/119 : z∼1 Lya emitters. I. 135 candidates from GALEX (Wold+, 2014)
J/ApJ/803/34 : z∼4-10 galaxies from HST legacy fields (Bouwens+, 2015)
J/ApJ/8/71 : UV mag of candidate galaxies at 3~<z~<8.5 (Finkelstein+, 2015)
J/ApJ/812/114 : Grism Lens-Amplified Survey from Space. I. (Treu+, 2015)
J/A+A/608/A8 : MUSE Hubble Ultra Deep Field Survey. VIII (Leclercq+, 2017)
J/ApJ/898/171 : CLEAR. II. SFRs of quiescent gal. (Estrada-Carpenter+, 2020)
J/ApJ/923/203 : CLEAR: HST G102 & G141 obs. of CANDELS gal. (Simons+, 2021)
Byte-by-byte Description of file: table2.dat
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Bytes Format Units Label Explanations
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1- 16 A16 --- ID Identifiers (1)
18- 18 A1 --- f_ID [e] Flag on ID (2)
20- 29 F10.6 deg RAdeg [53/190] Right Ascension, decimal degrees (J2000)
31- 40 F10.6 deg DEdeg [-28/62.4] Declination, decimal degrees (J2000)
42- 46 F5.2 mag Jmag [25/30] HST/WFC3 F125W magnitude (AB) from
CLEAR spectrum
48- 51 F4.2 mag E_Jmag [0/0.4] Upper uncertainty on Jmag
53- 56 F4.2 mag e_Jmag [0/0.3] Lower uncertainty on Jmag
58- 63 F6.2 mag UVMag [-23/-16] Absolute UV magnitude, MUV (3)
65- 68 F4.2 mag E_UVMag [0/1] Upper uncertainty on UVMag
70- 73 F4.2 mag e_UVMag [0/0.5] Lower uncertainty on UVMag
75- 78 F4.2 --- zphot [6/8.2] Photometric redshift
80- 83 F4.2 --- E_zphot [0.02/5.4] Upper (1σ) uncertainty on zphot
85- 88 F4.2 --- e_zphot [0.02/6] Lower (1σ) uncertainty on zphot
90- 90 A1 --- l_EWLya Limit flag on EWLya
92- 98 F7.1 0.1nm EWLya [3/14672]? Lyα rest-frame
equivalent width (4)
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Note (1): The listed IDs are encoded with their observed CLEAR fields and
matched 3D-HST IDs. We use 5400000+ IDs from
Finkelstein+ (2015, J/ApJ/810/71) for 3D-HST unmatched objects.
Note (2): Note as follows:
e = This object is not included in the analysis for the Lyα
EW distribution and the IGM transmission due to the tentative
emission-line detection.
Note (3): MUV is estimated from the averaged flux over a 1450-1550Å
bandpass from the best-fit galaxy SED model
Note (4): The 3σ upper limits, measured from the median flux limits
from individual spectra.
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History:
From electronic version of the journal
(End) Prepared by [AAS], Katia van der Woerd [CDS] 24-May-2024