The physics of galaxy assembly: spatially resolved IFS observations of high-redshift galaxies

Program leads: Santiago Arribas and Roberto Maiolino

Coordination with other GTO teams: selected observations in this program are conducted in coordination with the MIRI EC and NIRISS GTO team, allowing to share the slew overheads.

Program duration: 237 hours

Integral-field spectroscopy (IFS) observations of individual high-redshift galaxies with NIRSpec will enable us to investigate in detail the most important physical processes driving galaxy evolution across the cosmic epoch. The main goals of these observations are: to trace the distribution of star formation, to map the resolved properties of the stellar populations, to trace the gas kinematics (i.e. velocity fields, σv) and, therefore, determine dynamical masses and also identify non-virial motions (outflow and inflows), and to map metallicity gradients and dust extinction. These quantities will be mapped both for star forming galaxies and galaxies hosting active galaxy nuclei (AGNs). With this program we will extend up to z~6, and higher, the current ground-based studies relying on observations of the Hα line, which are limited to z ≃ 2.5 and which are affected by low sensitivity and modest angular resolution. The galaxy sample will be selected to be a good representation of the most massive Main Sequence (MS) of star-forming galaxies (including a few off-MS cases) and AGNs in the range 3-5 (both powerful starbursts and quasars). The samples will be drawn from previous optical, near-IR, and sub-mm and mm surveys.

Observations and targets:

Class and type of selection criteria

Redshift range

Spectral configurations

Average exposure time on target

Number of objects

SFGs (mainly optical + UV selected; a few objects are IR-selected)

3 < z < 6.3

one high resolution grating per target, prism for all targets

~4-5 hours at high spectral resolution

~1 hour at low spectral resolution



SFGs at the epoch of reionisation (LAE, ALMA)

6.5 < z < 9.1


one high or medium resolution grating per target, prism for all targets except 2

~3-5 hours at medium-high spectral resolution

~1 hour at low spectral resolution


AGNs (optical/x-ray/MIR selected) 3 < z < 5 one high resolution grating per target ~1 hour 13

AGNs/QSOs type 1

6 < z

one high-spectral resolution grating per target, prism for 3 out of 6

~3 hours at high spectral resolution

~1 hour at low spectral resolution



Observations and proposals:

Region Proposal Title Region Proposal Title
UDS #1215 Embedded in "NIRSpec WIDE MOS Survey - UDS" n/a #1222 Embedded in "Cosmic reionization, metal enrichment and host galaxies from quasar spectroscopy"


#1216 Integral Field Spectroscopy in GOODS-S n/a #1262 Integral Field Spectroscopy at z > 8



#1217 Integral Field Spectroscopy in COSMOS n/a #1263 NIRSpec and MIRI Spectroscopy of QSOs - Part 2



#1218 IFU Observations of one QSO at z~6 n/a #1264 NIRSpec and MIRI IFS of SMGs
n/a #1219 NIRSpec and MIRI spectroscopy of QSOs - part #3      
n/a #1220 NIRSpec IFS of BR1202 and LBQS0302