CLEAR: Boosted Ly alpha Transmission of the Intergalactic Medium in UV-bright Galaxies
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CLEAR : Boosted Ly alpha Transmission of the Intergalactic Medium in UV-bright Galaxies. / Jung, Intae; Papovich, Casey; Finkelstein, Steven L.; Simons, Raymond C.; Estrada-Carpenter, Vicente; Backhaus, Bren E.; Cleri, Nikko J.; Finlator, Kristian; Giavalisco, Mauro; Ji, Zhiyuan; Matharu, Jasleen; Momcheva, Ivelina; Straughn, Amber N.; Trump, Jonathan R.
In: Astrophysical Journal, Vol. 933, No. 1, 87, 01.07.2022.Research output: Contribution to journal › Journal article › Research › peer-review
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TY - JOUR
T1 - CLEAR
T2 - Boosted Ly alpha Transmission of the Intergalactic Medium in UV-bright Galaxies
AU - Jung, Intae
AU - Papovich, Casey
AU - Finkelstein, Steven L.
AU - Simons, Raymond C.
AU - Estrada-Carpenter, Vicente
AU - Backhaus, Bren E.
AU - Cleri, Nikko J.
AU - Finlator, Kristian
AU - Giavalisco, Mauro
AU - Ji, Zhiyuan
AU - Matharu, Jasleen
AU - Momcheva, Ivelina
AU - Straughn, Amber N.
AU - Trump, Jonathan R.
PY - 2022/7/1
Y1 - 2022/7/1
N2 - Reionization is an inhomogeneous process, thought to begin in small ionized bubbles of the intergalactic medium (IGM) around overdense regions of galaxies. Recent Ly alpha studies during the epoch of reionization show evidence that ionized bubbles formed earlier around brighter galaxies, suggesting higher IGM transmission of Ly alpha 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 Ly alpha 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 Ly alpha Emission at the End of Reionization Survey. We constrain the Ly alpha equivalent width (EW) distribution at 6.0 < z < 8.2, which is described by an exponential form, dN/dEW proportional to exp(-EW) W-0, with the characteristic e-folding scale width (W-0). We confirm a significant drop in the Ly alpha strength (i.e., W-0) at z > 6. Furthermore, we compare the redshift evolution of W-0 between galaxies at different UV luminosities. UV-bright (M-UV < -21 [i.e., L-UV > L*]) galaxies show weaker evolution with a decrease of 0.4 (+/- 0.2) dex in W-0 at z > 6, while UV-faint (M-UV > -21 [L-UV < L*]) galaxies exhibit a significant drop of 0.7-0.8 (+/- 0.2) dex in W-0 from z < 6 to z > 6. If the change in W-0 is proportional to the change in the IGM transmission for Ly alpha photons, then this is evidence that the transmission is "boosted" around UV-brighter galaxies, suggesting that reionization proceeds faster in regions around such galaxies.
AB - Reionization is an inhomogeneous process, thought to begin in small ionized bubbles of the intergalactic medium (IGM) around overdense regions of galaxies. Recent Ly alpha studies during the epoch of reionization show evidence that ionized bubbles formed earlier around brighter galaxies, suggesting higher IGM transmission of Ly alpha 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 Ly alpha 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 Ly alpha Emission at the End of Reionization Survey. We constrain the Ly alpha equivalent width (EW) distribution at 6.0 < z < 8.2, which is described by an exponential form, dN/dEW proportional to exp(-EW) W-0, with the characteristic e-folding scale width (W-0). We confirm a significant drop in the Ly alpha strength (i.e., W-0) at z > 6. Furthermore, we compare the redshift evolution of W-0 between galaxies at different UV luminosities. UV-bright (M-UV < -21 [i.e., L-UV > L*]) galaxies show weaker evolution with a decrease of 0.4 (+/- 0.2) dex in W-0 at z > 6, while UV-faint (M-UV > -21 [L-UV < L*]) galaxies exhibit a significant drop of 0.7-0.8 (+/- 0.2) dex in W-0 from z < 6 to z > 6. If the change in W-0 is proportional to the change in the IGM transmission for Ly alpha photons, then this is evidence that the transmission is "boosted" around UV-brighter galaxies, suggesting that reionization proceeds faster in regions around such galaxies.
KW - LYMAN-BREAK GALAXIES
KW - SIMILAR-TO 7
KW - EQUIVALENT WIDTH DISTRIBUTION
KW - EMISSION-LINE GALAXIES
KW - LENS-AMPLIFIED SURVEY
KW - LUMINOSITY FUNCTION
KW - COSMIC REIONIZATION
KW - EMITTING GALAXIES
KW - ESCAPE FRACTION
KW - ACCELERATED REIONIZATION
U2 - 10.3847/1538-4357/ac6fe7
DO - 10.3847/1538-4357/ac6fe7
M3 - Journal article
VL - 933
JO - Astrophysical Journal
JF - Astrophysical Journal
SN - 0004-637X
IS - 1
M1 - 87
ER -
ID: 315264367