Stellar IMF mass normalization for z~1 galaxies

DOI

The stellar initial mass function (IMF) is a key parameter for studying galaxy evolution. Here we measure the IMF mass normalization for a sample of 68 field galaxies in the redshift range 0.7-0.9 within the Extended Groth Strip. To do this we derive the total (stellar + dark matter) mass-to-light [(M/L)] ratio using axisymmetric dynamical models. Within the region where we have kinematics (about one half-light radius), the models assume (1) that mass follows light, implying negligible differences between the slope of the stellar and total density profiles, (2) constant velocity anisotropy ({beta}z=1-{sigma}z^2^/{sigma}R^2^=0.2), and (3) that galaxies are seen at the average inclination for random orientations (i.e., i=60{deg}, where i=90{deg} represents edge-on). The dynamical models are based on anisotropic Jeans equations, constrained by Hubble Space Telescope/Advanced Camera for Surveys imaging and the central velocity dispersion of the galaxies, extracted from good-quality spectra taken by the DEEP2 survey. The population (M/L) are derived from full-spectrum fitting of the same spectra with a grid of simple stellar population models. Recent dynamical modeling results from the ATLAS^3D^ project and numerical simulations of galaxy evolution indicate that the dark matter fraction within the central regions of our galaxies should be small. This suggests that our derived total (M/L) should closely approximate the stellar M/L. Our comparison of the dynamical (M/L) and the population (M/L) then implies that for galaxies with stellar mass M_*>~10^11^ M{sun}_, the average normalization of the IMF is consistent with a Salpeter slope, with a substantial scatter. This is similar to what is found within a similar mass range for nearby galaxies.

Cone search capability for table J/ApJ/786/L10/table1 (Results of dynamical models and multiple population fitting)

Identifier
DOI http://doi.org/10.26093/cds/vizier.17869010
Source https://dc.g-vo.org/rr/q/lp/custom/CDS.VizieR/J/ApJ/786/L10
Related Identifier https://cdsarc.cds.unistra.fr/viz-bin/cat/J/ApJ/786/L10
Related Identifier https://vizier.cds.unistra.fr/viz-bin/VizieR-2?-source=J/ApJ/786/L10
Metadata Access http://dc.g-vo.org/rr/q/pmh/pubreg.xml?verb=GetRecord&metadataPrefix=oai_b2find&identifier=ivo://CDS.VizieR/J/ApJ/786/L10
Provenance
Creator Shetty S.; Cappellari M.
Publisher CDS
Publication Year 2017
Rights https://cds.unistra.fr/vizier-org/licences_vizier.html
OpenAccess true
Contact CDS support team <cds-question(at)unistra.fr>
Representation
Resource Type Dataset; AstroObjects
Discipline Astrophysics and Astronomy; Cosmology; Galactic and extragalactic Astronomy; Natural Sciences; Observational Astronomy; Physics