TY - JOUR
T1 - Probing the Metal Enrichment of the Intergalactic Medium at z = 5-6 Using the Hubble Space Telescope
AU - Cai, Zheng
AU - Fan, Xiaohui
AU - Dave, Romeel
AU - Finlator, Kristian
AU - Oppenheimer, Ben
PY - 2017/10/26
Y1 - 2017/10/26
N2 - We test the galactic outflow model by probing associated galaxies of
four strong intergalactic C IV absorbers at z = 5-6 using the
Hubble Space Telescope (HST) Advanced Camera for Surveys (ACS) ramp
narrowband filters. The four strong C IV absorbers reside at z = 5.74,
5.52, 4.95, and 4.87, with column densities ranging from N C IV
= 1013.8 to 1014.8 cm-2.
At z = 5.74, we detect an I-dropout Lyα emitter (LAE) candidate
with a projected impact parameter of 42 physical kpc from the C IV
absorber. This LAE candidate has a Lyα-based star formation rate
(SFRLyα ) of 2 M ⊙ yr-1
and a UV-based SFR of 4 M ⊙ yr-1.
Although we cannot completely rule out that this I-dropout emitter may
be an [O II] interloper, its measured properties are consistent with the
C IV powered galaxy at z = 5.74. For C IV absorbers at z = 4.95 and z =
4.87, although we detect two LAE candidates with impact parameters of
160 and 200 kpc, such distances are larger than that predicted from the
simulations. Therefore, we treat them as nondetections. For the system
at z = 5.52, we do not detect LAE candidates, placing a 3σ upper
limit of SFRLyα ≈ 1.5 M ⊙
yr-1. In summary, in these four cases, we only detect
one plausible C IV source at z = 5.74. Combining the modest SFR of the
one detection and the three nondetections, our HST observations strongly
support that smaller galaxies (SFRLyα ≲ 2 M
⊙ yr-1) are main sources of
intergalactic C IV absorbers, and such small galaxies play a major role
in the metal enrichment of the intergalactic medium at z ≳ 5.
AB - We test the galactic outflow model by probing associated galaxies of
four strong intergalactic C IV absorbers at z = 5-6 using the
Hubble Space Telescope (HST) Advanced Camera for Surveys (ACS) ramp
narrowband filters. The four strong C IV absorbers reside at z = 5.74,
5.52, 4.95, and 4.87, with column densities ranging from N C IV
= 1013.8 to 1014.8 cm-2.
At z = 5.74, we detect an I-dropout Lyα emitter (LAE) candidate
with a projected impact parameter of 42 physical kpc from the C IV
absorber. This LAE candidate has a Lyα-based star formation rate
(SFRLyα ) of 2 M ⊙ yr-1
and a UV-based SFR of 4 M ⊙ yr-1.
Although we cannot completely rule out that this I-dropout emitter may
be an [O II] interloper, its measured properties are consistent with the
C IV powered galaxy at z = 5.74. For C IV absorbers at z = 4.95 and z =
4.87, although we detect two LAE candidates with impact parameters of
160 and 200 kpc, such distances are larger than that predicted from the
simulations. Therefore, we treat them as nondetections. For the system
at z = 5.52, we do not detect LAE candidates, placing a 3σ upper
limit of SFRLyα ≈ 1.5 M ⊙
yr-1. In summary, in these four cases, we only detect
one plausible C IV source at z = 5.74. Combining the modest SFR of the
one detection and the three nondetections, our HST observations strongly
support that smaller galaxies (SFRLyα ≲ 2 M
⊙ yr-1) are main sources of
intergalactic C IV absorbers, and such small galaxies play a major role
in the metal enrichment of the intergalactic medium at z ≳ 5.
KW - galaxies: high-redshift
KW - intergalactic medium
U2 - 10.3847/2041-8213/aa8fc6
DO - 10.3847/2041-8213/aa8fc6
M3 - Article
VL - 849
JO - Astrophysical Journal Letters
JF - Astrophysical Journal Letters
SN - 2041-8205
IS - 1
ER -