Stijn Wuyts
Gather.town id
BD11
Poster Title
On the spatial distribution of dust and star formation in galaxies
Institution
University of Bath
Abstract (short summary)
Resolved multi-wavelength and integral-field spectroscopic observations of galaxies allow a reconstruction of when and where within galaxies stars are formed. This can be pursued through a spatially resolved analysis of the fossil record or by observing more direct resolved probes of instantaneous star formation for galaxies across a range of redshifts. In order to obtain a picture of not just the unobscured but the overall star formation activity at all radii it is essential to account for spatial inhomogeneities in the dust distribution. I will report on lessons learned from studying tracers of star formation, dust extinction and dust re-emission on kiloparsec scales within galaxies from the peak epoch of cosmic star formation down to the present day. I will further pay attention to the new windows on resolved star formation that will soon be opened by JWST.
Plain text (extended) Summary
Resolving star formation across cosmic time
Stijn Wuyts - University of Bath
In Li et al. 2019 we study the relation between local star formation activity and dust attenuation within nearby star-forming galaxies from the MaNGA integral-field spectroscopic survey. The relation, as well as its secondary dependencies on local and global galaxy properties, can be reproduced by a superlinear Kennicutt-Schmidt relation, a dust-to-gas ratio scaling linearly with metallicity and a clumpy dust geometry. Simpler dust geometries fail, and inclination dependencies need to be accounted for.
One step up in redshift, to z ~ 1, HST grism observations allow the extraction of H-alpha maps as a tracer of instantaneous star formation on kiloparsec scales within star-forming galaxies. Dividing star-forming galaxies with stellar mass log(M*) = 10.5 - 11 into those lying above/on/below the star-forming main sequence, we find an overall shift in normalization of their specific star formation rate profiles. I.e., above-main-sequence galaxies feature excess star formation at all radii. The largest differences in specific star formation rate are seen in the galaxy centres, where below-main-sequence star-forming galaxies reveal the onset of inside-out quenching. The TNG50 simulation reproduces these trends remarkably well. Critically, this is no longer the case in a ‘TNG variation’ run where the AGN kinetic wind model is switched off.
A further step up in redshift, 0.2-arcsecond resolution ALMA observations reveal surprisingly compact dusty cores within a mass-selected sample of star-forming galaxies at z~2. The 870 micron dust continuum sizes are 2.3 times smaller than those measured in the rest-frame optical for the same galaxies, and 1.9 times smaller than those measured on stellar mass maps reconstructed from multi-band HST imaging. This suggests we are witnessing the rapid formation of a bulge component. The compact starburst puts most massive star-forming galaxies on the mass-size relation for quiescent galaxies at redshift z=2 within 300Myr, if the current star formation activity and its spatial distribution are maintained.
Finally, FRESCO is a JWST Cycle 1 NIRCam/grism programme that in 2 hour deep observations with the F444W filter will obtain spectroscopic redshifts for highly complete samples of line-emitting galaxies in the CANDELS-Deep fields from cosmic dawn to cosmic noon. High-resolution Balmer line maps will probe the spatial extent of instantaneous star formation well into the epoch of reionization. At cosmic noon, Paschen line profiles will yield a less dust sensitive probe of ongoing star formation.
Stijn Wuyts - University of Bath
In Li et al. 2019 we study the relation between local star formation activity and dust attenuation within nearby star-forming galaxies from the MaNGA integral-field spectroscopic survey. The relation, as well as its secondary dependencies on local and global galaxy properties, can be reproduced by a superlinear Kennicutt-Schmidt relation, a dust-to-gas ratio scaling linearly with metallicity and a clumpy dust geometry. Simpler dust geometries fail, and inclination dependencies need to be accounted for.
One step up in redshift, to z ~ 1, HST grism observations allow the extraction of H-alpha maps as a tracer of instantaneous star formation on kiloparsec scales within star-forming galaxies. Dividing star-forming galaxies with stellar mass log(M*) = 10.5 - 11 into those lying above/on/below the star-forming main sequence, we find an overall shift in normalization of their specific star formation rate profiles. I.e., above-main-sequence galaxies feature excess star formation at all radii. The largest differences in specific star formation rate are seen in the galaxy centres, where below-main-sequence star-forming galaxies reveal the onset of inside-out quenching. The TNG50 simulation reproduces these trends remarkably well. Critically, this is no longer the case in a ‘TNG variation’ run where the AGN kinetic wind model is switched off.
A further step up in redshift, 0.2-arcsecond resolution ALMA observations reveal surprisingly compact dusty cores within a mass-selected sample of star-forming galaxies at z~2. The 870 micron dust continuum sizes are 2.3 times smaller than those measured in the rest-frame optical for the same galaxies, and 1.9 times smaller than those measured on stellar mass maps reconstructed from multi-band HST imaging. This suggests we are witnessing the rapid formation of a bulge component. The compact starburst puts most massive star-forming galaxies on the mass-size relation for quiescent galaxies at redshift z=2 within 300Myr, if the current star formation activity and its spatial distribution are maintained.
Finally, FRESCO is a JWST Cycle 1 NIRCam/grism programme that in 2 hour deep observations with the F444W filter will obtain spectroscopic redshifts for highly complete samples of line-emitting galaxies in the CANDELS-Deep fields from cosmic dawn to cosmic noon. High-resolution Balmer line maps will probe the spatial extent of instantaneous star formation well into the epoch of reionization. At cosmic noon, Paschen line profiles will yield a less dust sensitive probe of ongoing star formation.
URL
s.wuyts@bath.ac.uk
Poster file