TY - JOUR
T1 - Investigating the physical properties of galaxies in the Epoch of Reionization with MIRI/JWST spectroscopy
AU - Álvarez-Márquez, J.
AU - Colina, L.
AU - Marques-Chaves, R.
AU - Ceverino, D.
AU - Alonso-Herrero, A.
AU - Caputi, K.
AU - García-Marín, M.
AU - Labiano, A.
AU - Le Fèvre, O.
AU - Norgaard-Nielsen, H. U.
AU - Östlin, G.
AU - Pérez-González, P. G.
AU - Pye, J. P.
AU - Tikkanen, T. V.
AU - van der Werf, P. P.
AU - Walter, F.
AU - Wright, G. S.
PY - 2019/8/23
Y1 - 2019/8/23
N2 - The James Webb Space Telescope (JWST) will provide deep imaging and
spectroscopy for sources at redshifts above 6, covering the entire Epoch
of Reionization (EoR, 6 <z <10), and enabling the detailed
exploration of the nature of the different sources during the first 1
Gyr of the history of the Universe. The Medium Resolution Spectrograph
(MRS) of the mid-IR Instrument (MIRI) will be the only instrument on
board JWST able to observe the brightest optical emission lines Hα
and [OIII]0.5007 μm at redshifts above 7 and 9, respectively,
providing key insights into the physical properties of sources during
the early phases of the EoR. This paper presents a study of the Hα
fluxes predicted by state-of-the-art FIRSTLIGHT cosmological simulations
for galaxies at redshifts of 6.5-10.5, and its detectability with MIRI.
Deep (40 ks) spectroscopic integrations with MRS will be able to detect
(signal-to-noise ratio > 5) EoR sources at redshifts above 7 with
intrinsic star formation rates (SFR) of more than 2 M⊙
yr-1, and stellar masses above 4-9 × 107
M⊙. These limits cover the upper end of the SFR and
stellar mass distribution at those redshifts, representing ˜6% and
˜1% of the predicted FIRSTLIGHT population at the 6.5-7.5 and
7.5-8.5 redshift ranges, respectively. In addition, the paper presents
realistic MRS simulated observations of the expected rest-frame optical
and near-infrared spectra for some spectroscopically confirmed EoR
sources recently detected by ALMA as [OIII]88 μm emitters. The MRS
simulated spectra cover a wide range of low metallicities from about
0.2-0.02 Z⊙, and different [OIII]88 μm/[OIII]0.5007
μm line ratios. The simulated 10 ks MRS spectra show S/N in the range
of 5-90 for Hβ, [OIII]0.4959,0.5007 μm, Hα and HeI1.083
μm emission lines of the currently highest spectroscopically
confirmed EoR (lensed) source MACS1149-JD1 at a redshift of 9.11,
independent of metallicity. In addition, deep 40 ksec simulated spectra
of the luminous merger candidate B14-65666 at 7.15 shows the MRS
capabilities of detecting, or putting strong upper limits on, the weak
[NII]0.6584 μm, [SII]0.6717,0.6731 μm, and [SIII]0.9069,0.9532
μm emission lines. These observations will provide the opportunity of
deriving accurate metallicities in bright EoR sources using the full
range of rest-frame optical emission lines up to 1 μm. In summary,
MRS will enable the detailed study of key physical properties such as
internal extinction, instantaneous star formation, hardness of the
ionizing continuum, and metallicity in bright (intrinsic or lensed) EoR
sources.
AB - The James Webb Space Telescope (JWST) will provide deep imaging and
spectroscopy for sources at redshifts above 6, covering the entire Epoch
of Reionization (EoR, 6 <z <10), and enabling the detailed
exploration of the nature of the different sources during the first 1
Gyr of the history of the Universe. The Medium Resolution Spectrograph
(MRS) of the mid-IR Instrument (MIRI) will be the only instrument on
board JWST able to observe the brightest optical emission lines Hα
and [OIII]0.5007 μm at redshifts above 7 and 9, respectively,
providing key insights into the physical properties of sources during
the early phases of the EoR. This paper presents a study of the Hα
fluxes predicted by state-of-the-art FIRSTLIGHT cosmological simulations
for galaxies at redshifts of 6.5-10.5, and its detectability with MIRI.
Deep (40 ks) spectroscopic integrations with MRS will be able to detect
(signal-to-noise ratio > 5) EoR sources at redshifts above 7 with
intrinsic star formation rates (SFR) of more than 2 M⊙
yr-1, and stellar masses above 4-9 × 107
M⊙. These limits cover the upper end of the SFR and
stellar mass distribution at those redshifts, representing ˜6% and
˜1% of the predicted FIRSTLIGHT population at the 6.5-7.5 and
7.5-8.5 redshift ranges, respectively. In addition, the paper presents
realistic MRS simulated observations of the expected rest-frame optical
and near-infrared spectra for some spectroscopically confirmed EoR
sources recently detected by ALMA as [OIII]88 μm emitters. The MRS
simulated spectra cover a wide range of low metallicities from about
0.2-0.02 Z⊙, and different [OIII]88 μm/[OIII]0.5007
μm line ratios. The simulated 10 ks MRS spectra show S/N in the range
of 5-90 for Hβ, [OIII]0.4959,0.5007 μm, Hα and HeI1.083
μm emission lines of the currently highest spectroscopically
confirmed EoR (lensed) source MACS1149-JD1 at a redshift of 9.11,
independent of metallicity. In addition, deep 40 ksec simulated spectra
of the luminous merger candidate B14-65666 at 7.15 shows the MRS
capabilities of detecting, or putting strong upper limits on, the weak
[NII]0.6584 μm, [SII]0.6717,0.6731 μm, and [SIII]0.9069,0.9532
μm emission lines. These observations will provide the opportunity of
deriving accurate metallicities in bright EoR sources using the full
range of rest-frame optical emission lines up to 1 μm. In summary,
MRS will enable the detailed study of key physical properties such as
internal extinction, instantaneous star formation, hardness of the
ionizing continuum, and metallicity in bright (intrinsic or lensed) EoR
sources.
KW - galaxies: high-redshift
KW - galaxies: formation
KW - galaxies: evolution
KW - infrared: galaxies
KW - telescopes
KW - STAR-FORMING GALAXIES
KW - EMISSION-LINE
KW - O-III
KW - REDSHIFT
KW - FEEDBACK
KW - ALPHA
KW - DUST
U2 - 10.1051/0004-6361/201935594
DO - 10.1051/0004-6361/201935594
M3 - Article
VL - 629
JO - Astronomy & astrophysics
JF - Astronomy & astrophysics
SN - 0004-6361
M1 - A9
ER -