Characterising KMOS and scaling relations in the rich cluster MS0451.6-0305

Thesis

This Thesis contains two parts. Part I details my work on KMOS, a new instrument for the VLT and Part II details my research on scaling relations for the massive galaxy cluster MS0451.6-0305.

Part I: The K-Band Multi-Object Spectrograph (KMOS) is a new near infra-red (NIR) instru- ment to be installed at the Very Large Telescope (VLT). KMOS is capable of spatially resolved kinematics via 24 deployable integral field units (IFUs), each with a 2.8′′ field of view. I describe my contribution to the construction and optical characterisation of the spectrograph modules and instrument as a whole.

Part II: GMOS-N spectroscopy has been used to obtain velocity dispersions (σ) and archival HST photometry has been used to determine the effective radii (Re) & average surface brightnesses within Re (⟨I⟩e) of 26 confirmed cluster members of MS0451.6-0305 at z = 0.55. The Kormendy Relation, Faber-Jackson Relation and Fundamental Plane have been produced for the cluster and have been compared to the results for a local reference sample in Coma. GMOS-N g′ and r′ band photometry has also been used to produce a Colour-Magnitude Relation for MS0451.6-0305.

It is found that the KR and FJR disagree at the 2.1σ level with respect to luminosity evolution since z = 0.55. When correcting for size-evolution (SE), the magnitude offsets agree and are consistent with passive evolution of the galaxy stellar populations from a single burst of star formation 9.8+4.5-1.7 Gyrs ago or z = 1.7+∞-0.6. The median offset in the FP relation for the SE corrected data is also consistent with this formation epoch. Evidence is found for the evolution of the FP tilt in MS0451.6-0305, where it is shown to be steeper than that of the Coma FP, when expressed as a relation between galaxy mass and M/L.

Authors: Masters, R; Richard Masters

• Publication date: 2012
• DOI: 10.5287/ora-n16m8nmnq
• Type of award: DPhil
• Level of award: Doctoral
• Awarding institution: Oxford University, UK
• Language: English
• Keywords: KMOS; IFU; infrared; cluster; spectrograph; MS0451
• Subjects: Astrophysics