J/A+A/672/A186 Ionizing photons in UV-faint z∼3-7 galaxies (Prieto-Lyon+, 2023)
The production of ionizing photons in UV-faint z ∼ 3-7 galaxies.
Prieto-Lyon G., Strait V., Mason C.A., Brammer G., Caminha G.B.,
Mercurio A., Acebron A., Bergamini P., Grillo C., Rosati P., Vanzella E.,
Castellano M., Merlin E., Paris D., Boyett K., Calabro A., Morishita T.,
Mascia S., Pentericci L., Roberts-Borsani G., Roy N., Treu T., Vulcani B.
<Astron. Astrophys. 672, A186 (2023)>
=2023A&A...672A.186P 2023A&A...672A.186P (SIMBAD/NED BibCode)
ADC_Keywords: Galaxies ; Ultraviolet ; Redshifts ; Equivalent widths
Keywords: quasars: emission lines - galaxies: high-redshift -
galaxies: evolution
Abstract:
The demographics of the production and escape of ionizing photons from
UV-faint early galaxies is a key unknown in discovering the primary
drivers of reionization. With the advent of JWST it is finally
possible to observe the rest-frame optical nebular emission from
individual sub-L* z>3 galaxies to measure the production of ionizing
photons, χion. Here we study a sample of 370 z∼3-7 galaxies
spanning -23<MUV←15.5 (median MUV~-18) with deep multi-band HST
and JWST/NIRCam photometry covering the rest-UV to optical from the
GLASS and UNCOVER JWST surveys. Our sample includes 102 galaxies with
Lyman-alpha emission detected in MUSE spectroscopy. We use H-alpha
fluxes inferred from NIRCam photometry to estimate the production rate
of ionizing photons which do not escape these galaxies
χion(1-fesc). We find median
log10χion(1-fesc)=25.33±0.47, with a broad intrinsic scatter
0.42dex, implying a broad range of galaxy properties and ages in our
UV-faint sample. Galaxies detected with Lyman-alpha have ∼0.1dex
higher χion(1-fesc), which is explained by their higher
H-alpha EW distribution, implying younger ages, higher sSFR and thus
more O/B stars. We find significant trends of increasing
χion(1-fesc) with increasing H-alpha EW, decreasing UV
luminosity, and decreasing UV slope, implying the production of
ionizing photons is enhanced in young, low metallicity galaxies. We
find no significant evidence for sources with very high ionizing
escape fraction (fesc>0.5) in our sample, based on their photometric
properties, even amongst the Lyman-alpha selected galaxies. This work
demonstrates that considering the full distribution of χion
across galaxy properties is important for assessing the primary
drivers of reionization.
Description:
We have inferred the hydrogen ionizing photon production rate, modulo
the escape fraction, in the largest sample of individual sub-L* z>3
galaxies to date, spanning -23≲MUV≲-15.5 with a median
MUV=-18.1, thanks to deep JWST/NIRCam imaging.
catalog.dat contains all data needed to reproduce the seven figures
showed in the publication.
File Summary:
--------------------------------------------------------------------------------
FileName Lrecl Records Explanations
--------------------------------------------------------------------------------
ReadMe 80 . This file
catalog.dat 512 370 All data needed to reproduce the seven figures
showed in the publication
--------------------------------------------------------------------------------
Byte-by-byte Description of file: catalog.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 5 A5 --- ID GLASS sources start with G,
UNCOVER start with U
7- 24 F18.16 deg RAdeg Right ascension (J2000)
26- 44 F19.15 deg DEdeg Declination (J2000)
46- 51 A6 --- GalType Galaxy type, Lyman Alpha Emitter or
non Lyman Alpha Emitter
53- 70 F18.16 --- z Redshift taken from Lyman Alpha
if LAE or from EAZY if nonLAE
72- 90 F19.16 --- mu Magnification
92-112 F21.18 --- e_mu ?=- Magnification error
114-132 F19.15 mag MUV UV magnitude measured at 1500Å (AB)
134-153 F20.18 mag e_MUV UV magnitude measured at 1500Å
error (AB)
155-174 F20.17 --- beta UV slope
176-195 F20.18 --- e_beta UV slope error
197-218 E22.16 10+7Hz/J Xion ?=- (1-fesc)χion (in Hz/erg unit)
220-241 E22.16 10+7Hz/J e_Xion ?=- (1-fesc)χion error
(in Hz/erg unit)
243-265 E23.16 mW/m2 FHa ?=- Flux Hα (in erg/cm2/s unit)
267-288 E22.16 mW/m2 e_FHa ?=- Flux Hα error
(in erg/cm2/s unit)
290-311 F22.16 0.1nm EWHa ?=- Hα equivalent width
313-332 F20.14 0.1nm e_EWHa []?=- Hα equivalent width error
334-355 E22.16 10mW/m2/nm ContHa ?=- Continuum flux density taken for
EWHa (in erg/cm2/s/Å unit)
357-378 E22.16 10mW/m2/nm e_ContHa ?=- Continuum flux density taken for
EWHa error (in erg/cm2/s/Å unit)
380-402 E23.16 mW/m2 FOIIIHb ?=- Flux OIII+Hb (in erg/cm2/s unit)
404-425 E22.16 mW/m2 e_FOIIIHb ?=- Flux OIII+Hb error
(in erg/cm2/s unit)
427-446 F20.15 0.1nm EWOIIIHb ?=- Equivalent width OIII+Hβ
448-466 F19.14 0.1nm e_EWOIIIHb []?=- Equivalent width OIII+Hβ
error
468-489 E22.16 10mW/m2/nm ContOIIIHb ?=- Continuum flux density taken for
EWOIII+Hb (in erg/cm2/s/Å unit)
491-512 E22.16 10mW/m2/nm e_ContOIIIHb ?=- Continuum flux density taken for
EWOIII+Hb error
(in erg/cm2/s/Å unit)
--------------------------------------------------------------------------------
Acknowledgements:
Gonzalo Prieto-Lyon, gonzalo.prieto(at)nbi.ku.dk
(End) Patricia Vannier [CDS] 14-Apr-2023