On the global structure of distant galactic disks

Abstract

Abstract. Radial and vertical profiles are determined for a sample of 34 edge-on disk galaxies in the HDFs, selected for their apparent diameter larger than 1.3 and their unperturbed morphology. The thickness and flatness of their galactic disks are determined and discussed with regard to evolution with redshift. We find that sub-L * spiral galaxies with z ∼ 1 have a relative thickness or flatness (characterized by h z /h the scaleheight to scalelength ratio) globally similar to those in the local Universe. A slight trend is however apparent, with the h z /h flatness ratio larger by a factor of ∼1.5 in distant galaxies if compared to local samples. In absolute value, the disks are smaller than in present-day galaxies. About half of the z ∼ 1 spiral disks show a non-exponential surface brightness distribution.

A photometric study of faint galaxies in the field of GRB 000926

“…Therefore, when the absolute magnitude of a spiral galaxy changes by 2 m , its size will change by a factor of ≈2.5. The observed change in galaxy size is smaller than this estimate, probably because the disks of many distant galaxies are poorly described by an exponential law (Reshetnikov et al 2003).…”

Observations and modeling of a clumpy galaxy atz = 1.6

“…We note that the rotation velocity measured in UDF 6462 is lower than what would be expected for the stellar mass from the Tully-Fisher relation (Conselice et al 2005). Since the thick disks of spiral galaxies are observed to have a lack of rotation compared to thin disks (Yoachim & Dalcanton 2005, clumpy evolution at high redshift is also a viable formation mechanism for thick disks, and indeed high-redshift disks are observed to be thick (Reshetnikov et al 2003;Elmegreen & Elmegreen 2006b). …”

Sky surveys and deep fields of ground-based and space telescopes

“…This slope change is believed to be a consequence of the differential evolution of spiral galaxies: at z ∼ 1, low-mass spirals become brighter by 1 m -2 m , while massive ones stay virtually as bright. Disks of 'edge-on' spirals at z ∼ 1 show a larger relative thickness (the ratio of the vertical and radial scales in the brightness distribution) and demonstrate vertical deformations of the plane (warps) more frequently than nearby objects [119,120]. Spectral studies of spiral galaxies suggest their chemical composition evolution: from z = 0 to z = 1, the metallicity of gas subsystems of galaxies decreases [121].…”