2018A&A...616A..30C


C.D.S. - SIMBAD4 rel 1.7 - 2020.07.14CEST17:47:08

2018A&A...616A..30C - Astronomy and Astrophysics, volume 616A, 30-30 (2018/8-1)

Accurately predicting the escape fraction of ionizing photons using rest-frame ultraviolet absorption lines.

CHISHOLM J., GAZAGNES S., SCHAERER D., VERHAMME A., RIGBY J.R., BAYLISS M., SHARON K., GLADDERS M. and DAHLE H.

Abstract (from CDS):

The fraction of ionizing photons that escape high-redshift galaxies sensitively determines whether galaxies reionized the early Universe. However, this escape fraction cannot be measured from high-redshift galaxies because the opacity of the intergalactic medium is large at high redshifts. Without methods to measure the escape fraction of high-redshift galaxies indirectly, it is unlikely that we will know what reionized the Universe. Here, we analyze the far-ultraviolet (UV) HI (Lyman series) and low-ionization metal absorption lines of nine low-redshift, confirmed Lyman continuum emitting galaxies. We use the HI covering fractions, column densities, and dust attenuations measured in a companion paper to predict the escape fraction of ionizing photons. We find good agreement between the predicted and observed Lyman continuum escape fractions (within 1.4σ) using both the HI andISM absorption lines. The ionizing photons escape through holes in the HI, but we show that dust attenuation reduces the fraction of photons that escape galaxies. This means that the average high-redshift galaxy likely emits more ionizing photons than low-redshift galaxies. Two other indirect methods accurately predict the escape fractions: the Lyα escape fraction and the optical [OIII]/[OII] flux ratio. We use these indirect methods to predict the escape fraction of a sample of 21 galaxies with rest-frame UV spectra but without Lyman continuum observations. Many of these galaxies have low escape fractions (fesc≤1%), but 11 have escape fractions >1%. Future studies will use these methods to measure the escape fractions of high-redshift galaxies, enabling upcoming telescopes to determine whether star-forming galaxies reionized the early Universe.

Abstract Copyright: © ESO 2018

Journal keyword(s): dark ages, reionization, first stars - galaxies: irregular - galaxies: ISM - galaxies: starburst

Simbad objects: 22

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Number of rows : 22

N Identifier Otype ICRS (J2000)
RA
ICRS (J2000)
DEC
Mag U Mag B Mag V Mag R Mag I Sp type #ref
1850 - 2020
#notes
1 ESO 350-38 AGN 00 36 52.489 -33 33 17.23   14.31 14.41 13.49   ~ 290 0
2 SHOC 148 Sy1 03 03 21.4140573561 -07 59 23.198200042     19.61     ~ 24 0
3 2MASX J04420810-3801108 H2G 04 42 08.110 -38 01 10.88 15.66 17.21 15.80 16.00   ~ 46 0
4 [DAA2009] SDSS J090002.79+223403.6 a LeG 09 00 03.319 +22 34 07.69           ~ 8 0
5 SDSS J091113.34+183108.1 Q? 09 11 13.3463735767 +18 31 08.195621007           ~ 16 0
6 2MASS J09215939+4509126 QSO 09 21 59.397 +45 09 12.38   18.57 18.31     ~ 48 0
7 SDSS J092532.36+140313.1 EmG 09 25 32.3641578796 +14 03 12.993552108           ~ 17 0
8 LARS 14 EmG 09 26 00.4041863336 +44 27 36.112149583           ~ 54 0
9 SGAS J095739+050928 LeG 09 57 38.740 +05 09 28.67           ~ 13 0
10 SDSS J105330.82+523752.8 Q? 10 53 30.8078248454 +52 37 52.791228755           ~ 17 0
11 NAME Cosmic Horseshoe G 11 48 33.10 +19 30 03.2           ~ 67 0
12 SDSS J115204.88+340049.8 Q? 11 52 04.8912713190 +34 00 49.896063418           ~ 13 0
13 SDSS J115448.85+244333.0 G 11 54 48.854 +24 43 33.04           ~ 13 0
14 SGAS J122651.3+215220 LeG 12 26 51.3 +21 52 20           ~ 18 0
15 SDSS J124423.37+021540.4 EmG 12 44 23.376 +02 15 40.46           ~ 19 0
16 EC 12476-2317 AGN 12 50 18.90 -23 33 57.6   16.29 15.46     ~ 57 0
17 Mrk 54 GiC 12 56 55.638 +32 26 51.50   15.1       ~ 76 0
18 SDSS J133303.95+624603.8 H2G 13 33 03.96 +62 46 03.8           ~ 14 0
19 [ITS2007] 53531-1827-503 EmG 14 29 47.0055554613 +06 43 34.978722649           ~ 20 0
20 SDSS J150342.82+364450.7 G 15 03 42.8276869198 +36 44 50.730581493           ~ 11 0
21 [BHG2011] SDSS J1527+0652 A1 LeG 15 27 48.950 +06 52 23.09           ~ 17 0
22 NAME Cosmic Eye G 21 35 12.730 -01 01 42.90           ~ 79 0

    Equat.    Gal    SGal    Ecl

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2020.07.14-17:47:08

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