Upload
clare-jackson
View
227
Download
3
Tags:
Embed Size (px)
Citation preview
Globular clusters in the galactic plane
Václav Glos
Star clusters
Main properities of globular clusters
- Age from half to nearly one Hubble time
- Tight gravitational bound of members
- Rare or none star formation
- Low metalicity
- Density profile fitable with Kings function
Credit: Marco Burali, Tiziano Capecchi, Marco Mancini
Positions of globular clusters in MW
Orbits of globular clusters in MW
Credit: Pearson Education
Absorption in visual light
Credit: Serge Brunier
Infrared solution
Milky Way in infrared
Credit: 2MASS
Finding globular clusters through disc
Credit: VSA
- Many field stars
- Non-homogenic reddening possibility
Difficulties:
Overdensity in star field
Credit: C. Moni Bidin et al.
Cluster members decontamination
Credit: C. Moni Bidin et al.
Determining cluster parameters
Cred
it: C
. Mon
i Bid
in e
t al.
Color Magnitude Diagram
- α-enhancement- metalicity- distance modulus- reddening- age
Red Giants spectra
- α-enhancement- metalicity
Globular clusters in the galactic plane
- Most in galactic bulge
- Confirmed GCs in trasition region between bulge and disc (for example GLIMPSE-C02 3,7 kpc from galactic center)
- One possible GC with distance from galaxy center 5 kpc VVV CL003
Harris W. (2003)
GLIMPSE-C02
- 3.7 kpc from galactic center
- Metal rich [Fe/H] = -0.33±0.14 in the scale of Zinn
- Compact – core radius 0.9 pc
Credit R. Kurtev et al.
VVV CL003
- 5 kpc from galactic center
- Metal rich [Fe/H] = −0.1 ± 0.2 possible open cluster?
- Deeper photometry needed
Credit: C. Moni Bidin et al.
Thank you for your attention.