Nikole Nielsen.pdf

The Circumgalactic Medium• Reservoir of gas which feeds future star formation• Material through which winds outflow, filaments accrete, &mergers are tidally stripped• Harbors a gas mass rivaling that in galaxies• Key to understanding galaxy evolution• What are the detailed physicalcharacteristics of the CGM forgalaxies of different masses,luminosities, & colors?NASA/CXC/M.Weiss; NASA/CXC/Ohio State/A.Gupta et al.

astronomy.nmsu.edu/cwc/GroupQuasar Absorption Lines ‐ MgII• Background QSO probesforeground galaxy throughabsorption – HI, CIV, OVI, MgIIQ0002+051MgII• Observed from the ground inthe optical with highresolution• Cold gas (3.5x10^4 K)• Traces HI column densities of16.5 < log N(HI) < 21.5+• Probes structures such asoutflows, inflows

Nielsen et al. 2013, in prepMAGIICAT –MgII Absorbing Galaxy Catalog• 182 isolated MgII galaxies• 0.1 < z < 1.1• D < 200 kpc• 0.03 Å < W r (2796) < 4.4 Å• upper limits down to 0.003 Å• B‐ and K‐band absolutemagnitudes M B , M K* *• Luminosities L B /L B , L K /L K• B‐K colors• Halo masses (M h ) from haloabundance matching

Amount of MgII vs Impact ParameterQ0002+051D = 26 kpcD = 36 kpc

arXiv:1211.1008, arXiv:1211.1380Amount of MgII vs Impact Parameter• Anti‐correlation between W r (2796) and D – 7.9 σ• Highest mass galaxies have larger EW at a given D• Mass segregation vanishes when normalizing by virialradius – 9.2 σ anti‐correlation• Amount and extent of MgII gas depends strongly on mass

Covering Fraction of MgII Gas• Patchiness of the CGM depends on luminosity and massNASA/CXC/M.Weiss; NASA/CXC/Ohio State/A.Gupta et al.Covering Fraction = 1 Covering Fraction < 1

arXiv:1211.1008, arXiv:1211.1380Covering Fraction of MgII Gas• Patchiness of the CGM depends on luminosity and mass

arXiv:1205:0245Galaxy Orientation90°M104BlueRed0°M82

arXiv:1205:0245Galaxy Orientation90°M104BlueRed0°OutflowsMore MgIIInflowsLess MgIIM82

Conclusions• Studying the CGM is crucial to understandinggalaxy evolution• MAGIICAT – Largest sample of MgII galaxies• The properties of the CGM strongly depend onthe host galaxy color, luminosity, and halomass• Bluer, brighter, and more massive galaxies have moregas out to further distances, and have less patchygaseous halos.• Galaxy orientation mattersThank you!