Morphologies of Galaxies in and around a Protocluster at z=2.300

Abstract

We present results from the first robust investigation of galaxy morphology as a function of environment at z>1.5. Our study is motivated by the fact that star-forming galaxies contained within a protocluster at z=2.3 in the HS1700+64 field have significantly older ages and larger stellar masses on average than those at similar redshifts but more typical environmental densities. In the analysis of HST/ACS images, we apply non-parametric statistics to characterize the rest-frame UV morphologies of a sample of 85 UV-selected star-forming galaxies at z=1.7-2.9, 22 of which are contained in the protocluster. The remaining 63 control-sample galaxies are not in the protocluster but have a similar mean redshift of <z>~2.3. We find no environmental dependence for the distributions of morphological properties. Combining the measured morphologies with the results of population synthesis modeling, we find only weak correlations, if any, between morphological and stellar population properties such as stellar mass, age, extinction and star-formation rate. Given the incomplete census of the protocluster galaxy population, and the lack of correlation between rest-frame UV morphology and star-formation history at z~2 within our sample, the absence of environmental trends in the distribution of morphological properties is not surprising. Additionally, using a larger sample of photometric candidates, we compare morphological distributions for 282 UV-selected and 43 near-IR-selected galaxies. While the difference in the degree of nebulosity between the two samples appears to be a byproduct of the fainter average rest-frame UV surface brightness of the near-IR-selected galaxies, we find that, among the lowest surface brightness galaxies, the near-IR-selected objects have significantly smaller angular sizes (abridged).

25 pages including 16 figures. Accepted for publication in ApJ. Version with full resolution figures available at http://www.astro.princeton.edu/~apeter/LBG/papers/peter2007_fullres.ps.gz

References in corpus (11)

• The Stellar, Gas and Dynamical Masses of Star-Forming Galaxies at z~2
• The DEEP2 Galaxy Redshift Survey: The Relationship Between Galaxy Properties and Environment at z ~ 1
• The DEEP2 Galaxy Redshift Survey: Evolution of the Color-Density Relation at 0.4 < z < 1.35
• NICMOS Imaging of DRGs in the HDF-S: A Relation Between Star-Formation and Size at z ~ 2.5
• The Morphological Diversities Among Star-forming Galaxies at High Redshifts in the Great Observatories Origins Deep Survey (GOODS)
• The Physical Nature of Rest-UV Galaxy Morphology During the Peak Epoch of Galaxy Formation
• The DEEP2 galaxy redshift survey: the evolution of the blue fraction in groups and the field
• The Dependence of the Mass Assembly History of Cold Dark Matter Halos on Environment
• Clustering of K-selected Galaxies at 2<z<3.5: Evidence for a Color-Density Relation
• Proto-Clusters with Evolved Populations around Radio Galaxies at z~2.5
• AEGIS: The Diversity of Bright Near-IR Selected Distant Red Galaxies

Cited by in corpus (11)

• Evolution of the Color-Magnitude Relation in Galaxy Clusters at z ~1 from the ACS Intermediate Redshift Cluster Survey
• The Ly-alpha Properties of Faint Galaxies at z2-3 with Systemic Redshifts and Velocity Dispersions from Keck-MOSFIRE
• The KBSS-KCWI Survey: The connection between extended Ly$\alpha$ halos and galaxy azimuthal angle at $z\sim 2-3$
• A blind CO detection of a Distant Red Galaxy in the HS1700+64 proto-cluster
• ZFIRE: Similar Stellar Growth in H$\alpha$-emitting Cluster and Field Galaxies at z~2
• Environmental impacts on the rest-frame UV size and morphology ofstar-forming galaxies at $z\sim 2$
• Extended star-forming region within galaxies in a dense proto-cluster core at z=2.53
• Spitzer's View of the Candidate Cluster and Protocluster Catalog (CCPC)
• Resolving a merger in a hyper-luminous submillimeter galaxy at z=2.82
• Brighter and More Massive Galaxies in the Vicinity of Lyman-alpha Nebulae
• Probing the influence of the protocluster environment on galaxy morphology at z = 2.23