star counts and the galactic structure xu yan supervisor: deng li cai
TRANSCRIPT
![Page 1: Star Counts and The Galactic Structure Xu Yan Supervisor: Deng Li Cai](https://reader035.vdocuments.mx/reader035/viewer/2022062404/551b86a5550346942b8b4aff/html5/thumbnails/1.jpg)
Star Counts and The Galactic Structure
Xu Yan
Supervisor: Deng Li Cai
![Page 2: Star Counts and The Galactic Structure Xu Yan Supervisor: Deng Li Cai](https://reader035.vdocuments.mx/reader035/viewer/2022062404/551b86a5550346942b8b4aff/html5/thumbnails/2.jpg)
Introduction
Sloan digital sky survey Synthetic star counts model Future plan
![Page 3: Star Counts and The Galactic Structure Xu Yan Supervisor: Deng Li Cai](https://reader035.vdocuments.mx/reader035/viewer/2022062404/551b86a5550346942b8b4aff/html5/thumbnails/3.jpg)
Sloan Digital Sky Survey
Five broad band filters,u’,g’,r’,i’,z’
effective wavelengths, 3450Å, 4760Å, 6280Å, 7690Å,9250Å
point-source magnitude limit, 22.3, 23.3, 23.1, 22.3, 20.8 (s/n=5)
Pixels subtend 0”.4, PSF width1.4" median in r Exposure time in each band is 54.1s ‘run’, six 13’.5 wide strips, ‘rerun’, 12’.5
2o.5 wide stripe (Chen et. al. 2001)
![Page 4: Star Counts and The Galactic Structure Xu Yan Supervisor: Deng Li Cai](https://reader035.vdocuments.mx/reader035/viewer/2022062404/551b86a5550346942b8b4aff/html5/thumbnails/4.jpg)
45 survey stripes
![Page 5: Star Counts and The Galactic Structure Xu Yan Supervisor: Deng Li Cai](https://reader035.vdocuments.mx/reader035/viewer/2022062404/551b86a5550346942b8b4aff/html5/thumbnails/5.jpg)
![Page 6: Star Counts and The Galactic Structure Xu Yan Supervisor: Deng Li Cai](https://reader035.vdocuments.mx/reader035/viewer/2022062404/551b86a5550346942b8b4aff/html5/thumbnails/6.jpg)
![Page 7: Star Counts and The Galactic Structure Xu Yan Supervisor: Deng Li Cai](https://reader035.vdocuments.mx/reader035/viewer/2022062404/551b86a5550346942b8b4aff/html5/thumbnails/7.jpg)
DR2 Sky Coverage 3324 sq deg Equatorial
http://www.sdss.org/dr2/coverage/index.html
![Page 8: Star Counts and The Galactic Structure Xu Yan Supervisor: Deng Li Cai](https://reader035.vdocuments.mx/reader035/viewer/2022062404/551b86a5550346942b8b4aff/html5/thumbnails/8.jpg)
DR2 Sky Coverage Galactic
http://www.sdss.org/dr2/coverage/index.html
![Page 9: Star Counts and The Galactic Structure Xu Yan Supervisor: Deng Li Cai](https://reader035.vdocuments.mx/reader035/viewer/2022062404/551b86a5550346942b8b4aff/html5/thumbnails/9.jpg)
Synthetic model
ρ(R,Z), Φ(Mass) → surface number density of some direction of some population
each population → [Fe/H], Mass, Age From Isochrone → [Fe/H], Teff, g Color of each star
![Page 10: Star Counts and The Galactic Structure Xu Yan Supervisor: Deng Li Cai](https://reader035.vdocuments.mx/reader035/viewer/2022062404/551b86a5550346942b8b4aff/html5/thumbnails/10.jpg)
Robin(2003)group
Age(Gyr) [Fe/H](dex) IMF ρ0(MΘPC-3)
1 0 – 0.15 0.010.12 dn/dm=m-1.6
(M<1MΘ)
dn/dm=m-3
(M≥1MΘ)
4*10-3
2 0.15 - 1 0.030.12 7.9*10-3
3 1 - 2 0.030.1 6.2*10-3
4 2 - 3 0.010.11 4*10-3
5 3 - 5 -0.070.18 5.8*10-3
6 5 - 7 -0.140.17 4.9*10-3
7 7 - 10 -0.370.2 6.6*10-3
8 11 -0.780.3 dn/dm=m-0.5 1.34*10-3
9 14 -1.780.5 9.32*10-3
![Page 11: Star Counts and The Galactic Structure Xu Yan Supervisor: Deng Li Cai](https://reader035.vdocuments.mx/reader035/viewer/2022062404/551b86a5550346942b8b4aff/html5/thumbnails/11.jpg)
91
22
1
)()(
)(,
AAA
dRRdMassRdMassA
MassPMFZRdAMass
Mass R
i
i
![Page 12: Star Counts and The Galactic Structure Xu Yan Supervisor: Deng Li Cai](https://reader035.vdocuments.mx/reader035/viewer/2022062404/551b86a5550346942b8b4aff/html5/thumbnails/12.jpg)
]/||exp[]/)(exp[),( 2100 hzhrxMrd
87
4/1
0
])/(exp[
e
es
rr
rrbCsr
)()( massIMFmass
Chen (2001)
Bahcall(1980)
5.02
36.11
)(
)()(
mcM
mmcMRobin(2003)
![Page 13: Star Counts and The Galactic Structure Xu Yan Supervisor: Deng Li Cai](https://reader035.vdocuments.mx/reader035/viewer/2022062404/551b86a5550346942b8b4aff/html5/thumbnails/13.jpg)
PMF ~ IMF Mass density convert to number density
is normalized IMF
Logz=1.03[Fe/H]-1.689 (Carraro et. al. 1994) z, Age, Mass
dm
dn
dmdm
dnmcymassdenist dm
dm
dncnumdensity
![Page 14: Star Counts and The Galactic Structure Xu Yan Supervisor: Deng Li Cai](https://reader035.vdocuments.mx/reader035/viewer/2022062404/551b86a5550346942b8b4aff/html5/thumbnails/14.jpg)
Pseudo-random in age and metalicity
Group1,Mass: 0.1505000D+00 0.1515000D+00 (M☉)
![Page 15: Star Counts and The Galactic Structure Xu Yan Supervisor: Deng Li Cai](https://reader035.vdocuments.mx/reader035/viewer/2022062404/551b86a5550346942b8b4aff/html5/thumbnails/15.jpg)
The tables of bolometric corrections have been applied to Padova database of stellar evolutionary tracks and isochrones. http://pleiadi.pd.astro.it.
Interpolate in SDSS Isochrone of Giradi(2004) and Ma(2001)
0
02
1
2
1log5.2
Ss m
dSf
dSf
m
SbolS MMBC
0
0
4.0
2,
2
1
2
1
10
log5.2
]/)10(4log[5.2
S
A
bolbolS
m
dSf
dSF
LFpcMBC
Stellar spectra Fλ , spectral library
![Page 16: Star Counts and The Galactic Structure Xu Yan Supervisor: Deng Li Cai](https://reader035.vdocuments.mx/reader035/viewer/2022062404/551b86a5550346942b8b4aff/html5/thumbnails/16.jpg)
'1'0 2/sinhlog5.2 bfabmf
ea log5.2
'0 log5.20 bm
Lupton et al (1999)
fmfm log5.2)( 0
AB magnitude scale
00, ABm
121200, 10631.3 Hzcmsergf AB
![Page 17: Star Counts and The Galactic Structure Xu Yan Supervisor: Deng Li Cai](https://reader035.vdocuments.mx/reader035/viewer/2022062404/551b86a5550346942b8b4aff/html5/thumbnails/17.jpg)
u-g g-r r-I i-z
107 , 10 8,109,1010 yr (Giradi 2004)
![Page 18: Star Counts and The Galactic Structure Xu Yan Supervisor: Deng Li Cai](https://reader035.vdocuments.mx/reader035/viewer/2022062404/551b86a5550346942b8b4aff/html5/thumbnails/18.jpg)
12Gyr, z=0.0001,0.0004,0.001,0.004,0.008,0.019,0.03 (Giradi2004)
![Page 19: Star Counts and The Galactic Structure Xu Yan Supervisor: Deng Li Cai](https://reader035.vdocuments.mx/reader035/viewer/2022062404/551b86a5550346942b8b4aff/html5/thumbnails/19.jpg)
isoc_sloan/isoc_z0.dat.gz Metal-free models from Ma01.
isoc_sloan/isoc_z0001.dat.gz isoc_sloan/isoc_z0004.dat.gz isoc_sloan/isoc_z001.dat.gz isoc_sloan/isoc_z004.dat.gz isoc_sloan/isoc_z008.dat.gz isoc_sloan/isoc_z019.dat.gz
isoc_sloan/isoc_z030.dat.gz
Basic set obtained by combining Gi00+Gi01 (low- and intermediate-mass stars) with Be94+Gi96 (high masses) isochrones. With overshooting
![Page 20: Star Counts and The Galactic Structure Xu Yan Supervisor: Deng Li Cai](https://reader035.vdocuments.mx/reader035/viewer/2022062404/551b86a5550346942b8b4aff/html5/thumbnails/20.jpg)
R=50PC z=41.44PC
Ra=180 dec=60 skycoverage=1srL=134.4 b=55.97
![Page 21: Star Counts and The Galactic Structure Xu Yan Supervisor: Deng Li Cai](https://reader035.vdocuments.mx/reader035/viewer/2022062404/551b86a5550346942b8b4aff/html5/thumbnails/21.jpg)
R=150PC z=124.31PC
![Page 22: Star Counts and The Galactic Structure Xu Yan Supervisor: Deng Li Cai](https://reader035.vdocuments.mx/reader035/viewer/2022062404/551b86a5550346942b8b4aff/html5/thumbnails/22.jpg)
R=250PC z=207.186PC
![Page 23: Star Counts and The Galactic Structure Xu Yan Supervisor: Deng Li Cai](https://reader035.vdocuments.mx/reader035/viewer/2022062404/551b86a5550346942b8b4aff/html5/thumbnails/23.jpg)
R=350PC z=290.06PC
![Page 24: Star Counts and The Galactic Structure Xu Yan Supervisor: Deng Li Cai](https://reader035.vdocuments.mx/reader035/viewer/2022062404/551b86a5550346942b8b4aff/html5/thumbnails/24.jpg)
Mass(M ) Log(age) group z logT logg☉ u g r u-g g-r 0.200000 9.76540 61 0.0233971 3.62080 2.98324 6.95622 4.73258 3.71290 2.22364 1.01968. 0.200000 9.83367 61 0.0131369 3.61070 3.21589 7.97221 5.66942 4.60236 2.30279 1.06706.
R=450PC z=372.94PC
![Page 25: Star Counts and The Galactic Structure Xu Yan Supervisor: Deng Li Cai](https://reader035.vdocuments.mx/reader035/viewer/2022062404/551b86a5550346942b8b4aff/html5/thumbnails/25.jpg)
Mass(M☉) Log(age) group z logT logg u g r u-g g-r0.200000 9.19340 31 0.0124033 3.63555 3.41523 7.13436 4.98482 4.02208 2.14954 0.962740 0.200000 9.75101 61 0.0118220 3.63816 3.01763 6.46198 4.38647 3.44567 2.07551 0.940800 0.200000 9.71720 61 0.0124870 3.62821 3.20643 7.34673 5.19215 4.20510 2.15458 0.987050
R=550PC z=455.81PC
![Page 26: Star Counts and The Galactic Structure Xu Yan Supervisor: Deng Li Cai](https://reader035.vdocuments.mx/reader035/viewer/2022062404/551b86a5550346942b8b4aff/html5/thumbnails/26.jpg)
R=650PC z=538.68
![Page 27: Star Counts and The Galactic Structure Xu Yan Supervisor: Deng Li Cai](https://reader035.vdocuments.mx/reader035/viewer/2022062404/551b86a5550346942b8b4aff/html5/thumbnails/27.jpg)
R=750PC z=621.56PC
![Page 28: Star Counts and The Galactic Structure Xu Yan Supervisor: Deng Li Cai](https://reader035.vdocuments.mx/reader035/viewer/2022062404/551b86a5550346942b8b4aff/html5/thumbnails/28.jpg)
R=850PC z=704.43PC
![Page 29: Star Counts and The Galactic Structure Xu Yan Supervisor: Deng Li Cai](https://reader035.vdocuments.mx/reader035/viewer/2022062404/551b86a5550346942b8b4aff/html5/thumbnails/29.jpg)
R=950PC z=787.37PC
![Page 30: Star Counts and The Galactic Structure Xu Yan Supervisor: Deng Li Cai](https://reader035.vdocuments.mx/reader035/viewer/2022062404/551b86a5550346942b8b4aff/html5/thumbnails/30.jpg)
![Page 31: Star Counts and The Galactic Structure Xu Yan Supervisor: Deng Li Cai](https://reader035.vdocuments.mx/reader035/viewer/2022062404/551b86a5550346942b8b4aff/html5/thumbnails/31.jpg)
Classify metallicity z>0.019 0.019>z>0.004 z<0.004
![Page 32: Star Counts and The Galactic Structure Xu Yan Supervisor: Deng Li Cai](https://reader035.vdocuments.mx/reader035/viewer/2022062404/551b86a5550346942b8b4aff/html5/thumbnails/32.jpg)
Classify age
Age<12Gyr 5Gyr<Age<12Gyr Age<5Gyr
![Page 33: Star Counts and The Galactic Structure Xu Yan Supervisor: Deng Li Cai](https://reader035.vdocuments.mx/reader035/viewer/2022062404/551b86a5550346942b8b4aff/html5/thumbnails/33.jpg)
RA=180 DEC=60 33289
Compare result of model with observation
![Page 34: Star Counts and The Galactic Structure Xu Yan Supervisor: Deng Li Cai](https://reader035.vdocuments.mx/reader035/viewer/2022062404/551b86a5550346942b8b4aff/html5/thumbnails/34.jpg)
![Page 35: Star Counts and The Galactic Structure Xu Yan Supervisor: Deng Li Cai](https://reader035.vdocuments.mx/reader035/viewer/2022062404/551b86a5550346942b8b4aff/html5/thumbnails/35.jpg)
![Page 36: Star Counts and The Galactic Structure Xu Yan Supervisor: Deng Li Cai](https://reader035.vdocuments.mx/reader035/viewer/2022062404/551b86a5550346942b8b4aff/html5/thumbnails/36.jpg)
![Page 37: Star Counts and The Galactic Structure Xu Yan Supervisor: Deng Li Cai](https://reader035.vdocuments.mx/reader035/viewer/2022062404/551b86a5550346942b8b4aff/html5/thumbnails/37.jpg)
4422
![Page 38: Star Counts and The Galactic Structure Xu Yan Supervisor: Deng Li Cai](https://reader035.vdocuments.mx/reader035/viewer/2022062404/551b86a5550346942b8b4aff/html5/thumbnails/38.jpg)
![Page 39: Star Counts and The Galactic Structure Xu Yan Supervisor: Deng Li Cai](https://reader035.vdocuments.mx/reader035/viewer/2022062404/551b86a5550346942b8b4aff/html5/thumbnails/39.jpg)
Future plan
Constrain model with observation Do further deducing for physical parameter
of observational data to obtain distance Pick up stars that have special meaning to
the structure of the Galaxy
![Page 40: Star Counts and The Galactic Structure Xu Yan Supervisor: Deng Li Cai](https://reader035.vdocuments.mx/reader035/viewer/2022062404/551b86a5550346942b8b4aff/html5/thumbnails/40.jpg)
Thank you!