tereza jeŘÁbkovÁ · 2017. 9. 20. · kirk+2012, zonoozi+2016, haghi+2017,romano+(2017) centres...
TRANSCRIPT
STELLAR POPULATIONS IN EXTREME STAR BURST CLUSTERS AND ULTRA-COMPACT DWARF GALAXIES (UCD )
TEREZA JEŘÁBKOVÁ ESO GARCHING & UNIVERSITY OF BONN & CHARLES UNIVERSITY IN PRAGUE
MODEST UNDER PRAGUE’S STARRY SKIES CZECH REPUBLIC 18-22 OF SEPTEMBER 2017
www: sirrah.troja.mff.cuni.cz/~tereza email: [email protected]
TH
1
17
s
MOTIVATION STELLAR POPULATIONS WHAT WE CAN SEE NEARBY?
Galactic star forming regions
2
similar environments ( ) and basically solar metallicitywe observe very young objects (formation snapshot)
at similar initial conditions it is difficult to study environmental dependencies of star formation and stellar IMF
BUT
%, T, . . .
s
MOTIVATION STELLAR POPULATIONS WHAT WE CAN SEE NEARBY?
Galactic star forming regions
3
Older objects - Galactic star clusters and GCs and extragalactic UCDs
similar environments ( ) and basically solar metallicity
BUT
most likely formed under different physical conditions compared to local star formation
%, T, . . .
BUT highly evolved systems degenerate with age (initial conditions?)we observe only low mass stars and dynamically evolved systems
s s
at similar initial conditions it is difficult to study environmental dependencies of star formation and stellar IMF
we observe very young objects (formation snapshot)
MOTIVATION STELLAR POPULATIONS WHAT WE CAN SEE NEARBY?
Galactic star forming regions
4
Older objects - Galactic star clusters and GCs and extragalactic UCDs
similar environments ( ) and basically solar metallicity
BUT
most likely formed under different physical conditions compared to local star formation
%, T, . . .
BUT highly evolved systems degenerate with agewe observe only low mass stars and dynamically evolved systems
QUESTION: CAN WE OBSERVE PROGENITORS OF GC AND UCD ?s s
at similar initial conditions it is difficult to study environmental dependencies of star formation and stellar IMF
we observe very young objects (formation snapshot)
LAYOUT OF THE PROJECT
Jerabkova T., Kroupa P., Dabringhausen J., Hilker M., Bekki K., A&A, 2017, in press
5
https://arxiv.org/abs/1708.07127
Using PEGASE code (Fioc & Rocca-Volmerange 1997)1. Construction of stellar population models for progenitors of UCDs and GCs
Aim: How extreme star formation environments may appear at high redshifts.
(Predictions of observables with James Web Space Telescope)
2. Computation of photometric (magnitudes, colours) and other (SN rates, spectral slopes) diagnostics
With underlying question: Can a systematic variation of the stellar IMF in massive star-bursts be confirmed using observations with the JWST?
+ potential for constraining the formation of multiple stellar populations
see also (Renzini,A&A,2017)
see e.g Glazebrook+(2017,Nat.) & Vanzella+(2017,MNRAS)
ASSUMPTIONS & PARAMETRISATION OF THE STAR CLUSTER SPACE
1. Assumption: UCDs and GCs form by monolithic collapse6
(At least some need to Jerabkova +, A&A, 2017)+ formation channel through merged star cluster complexes can be constrained
2. Assumption: Red-shift computed based on CDM and Planck data⇤(Planck Collaboration +, 2016a,b)
3. Assumption: General shape of the IMF: multi-power lawCanonical IMF - nearby star forming regions (Kroupa 2001) - green in all plots
≠1 0 1 2log (m [M§])
≠4
≠2
0
2
log›
(m)[r
elat
ive]
Salpeter slope↵ =2.3
canonical IMF
↵1 = 1.3↵2 = 2.3
↵3 =
2.3
redshift considered: z=0,3,6,9 (13.5, 2.1, 0.9, 0.6 Gyr after Big-Bang)
Jerabkova T., Kroupa P., Dabringhausen J., Hilker M., Bekki K., A&A, 2017, in press
ASSUMPTIONS & PARAMETRISATION OF THE STAR CLUSTER SPACE 7
≠1 0 1 2log (m [M§])
≠4
≠2
0
2
log›
(m)[r
elat
ive]
BOTTOM-HEAVY
Salpeter slope
canonical IMF
↵1 = 1.3↵2 = 2.3
↵3 =
2.3
TOP-HEAVYmore massive stars per cluster mass
Top-heavy IMF if: large densities, small [Fe/H]
Bottom-heavy IMF if: metal rich (Marks+2012)
large densities (Conroy & van Dokkum)
Larson (1998), Adams+(1996), Dib+(2007), Papadopoulos (2010) Dabringhausen 2009&2010,Marks+2012, Kirk+2012, Zonoozi+2016, Haghi+2017,Romano+(2017)
centres of ellipticalsChabrier+(2014) - increased density leads to bottom heavy IMFBUT potential problems: Bertelli Motta+(2016), Liptai+(2017)
1. Assumption: UCDs and GCs form by monolithic collapse(At least some need to Jerabkova +, A&A, 2017)
+ formation channel through merged star cluster complexes can be constrained2. Assumption: Red-shift computed based on CDM and Planck data⇤
(Planck Collaboration +, 2016a,b)
3. Assumption: General shape of the IMF: multi-power lawCanonical IMF - nearby star forming regions (Kroupa 2001) - green in all plots
redshift considered: z=0,3,6,9 (13.5, 2.1, 0.9, 0.6 Gyr after Big-Bang)
Jerabkova T., Kroupa P., Dabringhausen J., Hilker M., Bekki K., A&A, 2017, in press
ASSUMPTIONS & PARAMETRISATION OF THE STAR CLUSTER SPACE 8
≠1 0 1 2log (m [M§])
≠4
≠2
0
2
log›
(m)[r
elat
ive]
BOTTOM-HEAVY
Salpeter slope
canonical IMF
↵1 = 1.3↵2 = 2.3
↵3 =
2.3
TOP-HEAVYmore massive stars per cluster mass
Top-heavy IMF
Bottom-heavy IMF↵1 = ↵2 = ↵3 = 2.3
↵1 = ↵2 = ↵3 = 3.0Dabringhausen+(2008), SAL IMF
van Dokkum&Conroy+(2010), vDC IMF
varies with initial conditionsMarks+(2012), MKDP IMF↵3 < 2.3
CAN IMF↵1 = 1.3, ↵2 = ↵3 = 2.3
1. Assumption: UCDs and GCs form by monolithic collapse(At least some need to Jerabkova +, A&A, 2017)
+ formation channel through merged star cluster complexes can be constrained2. Assumption: Red-shift computed based on CDM and Planck data⇤
(Planck Collaboration +, 2016a,b)
3. Assumption: General shape of the IMF: multi-power lawCanonical IMF - nearby star forming regions (Kroupa 2001) - green in all plots
redshift considered: z=0,3,6,9 (13.5, 2.1, 0.9, 0.6 Gyr after Big-Bang)
Jerabkova T., Kroupa P., Dabringhausen J., Hilker M., Bekki K., A&A, 2017, in press
ASSUMPTIONS & PARAMETRISATION OF THE STAR CLUSTER SPACE 9
SAL IMF vDC IMF MKDP IMFCAN IMFKroupa(2001) Marks+(2012) Dabringhausen+(2008) van Dokkum&Conroy+(2010)
1. Assumption: UCDs and GCs form by monolithic collapse(At least some need to Jerabkova +, A&A, 2017)
+ formation channel through merged star cluster complexes can be constrained2. Assumption: Red-shift computed based on CDM and Planck data⇤
(Planck Collaboration +, 2016a,b)
3. Assumption: General shape of the IMF: multi-power lawredshift considered: z=0,3,6,9 (13.5, 2.1, 0.9, 0.6 Gyr after Big-Bang)
4. Assumption: other parameterstime grid: (1-10 Myr, 10-100 Myr, 100-1000 Myr, 1-13 Gyr)
Star formation history: simultaneous, constant over 5-10 Myr
initial stellar masses: , SFE = 0.33106, 107, 108, 109 M�Megeath+(2016), Banerjee(2017)
[Fe/H] = -2, 0
PEGASE time-dependent stellar population synthesis code Fioc&Rocca-Volmerange(1997) (comparison with SB99)
Jerabkova T., Kroupa P., Dabringhausen J., Hilker M., Bekki K., A&A, 2017, in press
RESULTS
For the introduced parameters we construct a grid of SEDs which allow us to construct observables and other characteristic.
10
For the first time we predict how the progenitors of UCDs and massive GCs might look like when formed at high redshifts and compute observability with the JWST.
Luminosity, color-(color)magnitude diagrams, SED slopesMass-to-light ratios, supernovae rates for each set of parameters
Jerabkova T., Kroupa P., Dabringhausen J., Hilker M., Bekki K., A&A, 2017, in press
103 104 105
⁄ [A]
10≠12
10≠11
F‹[(e
rgs≠
1 cm≠
2 Hz≠
1 )] 6Myr
7Myr
8Myr
9Myr
10Myr
20Myr
MKD IMF
Marks et al. (2012)
?
103 104 105
⁄ [A]
6Myr7Myr8Myr
9Myr10Myr20Myr
CAN IMF
0.0 0.1 0.2mJ ≠mK
6.5
7.0
7.5
8.0
mK≠mN
z=9zoomed plot
tmax|z=9 ¥ 0.6Gyr
0.01 Gyr
0.1 Gyr
0.0
0.5
1.0
1.5
2.0
2.5
3.0
3.5
4.0
log(
time[
Myr
])
MKDP IMF vDC IMF
J and K filter cover similar wavelength range as F115W and F200W (NIRCam)
N filter covers similar wavelength range as F1000W (MIRI)
RESULTS: BOLOMETRIC LUMINOSITY 11
100 101 102 103 104
time [Myr]
106
107
108
109
1010
1011
1012
1013
Lbol[L§]
MUCD = 108 M§
Lbol ÃMUCD (NOT for MKDP)
10 7M§
10 8M§
10 9M§
[Fe/H]=≠2
[Fe/H]= 0
MKDP IMFCAN IMFSAL IMFvDC IMF
≠27.5
≠25.0
≠22.5
≠20.0
≠17.5
≠15.0
≠12.5
≠10.0
Mbol[m
ag]
UC
DD
ATA
QUASARS
SUPE
RN
OVA
E
Consistency check
As bright as quasars!
larg
er st
ella
r mas
s
top-
heav
y IM
F
Degeneracies
Supernova explosions may cause photometric variability
Jerabkova T., Kroupa P., Dabringhausen J., Hilker M., Bekki K., A&A, 2017, in press
age
of th
e sy
stem
RESULTS: COLOR-MAGNITUDE DIAGRAM 12
≠0.5 0.0 0.5 1.0 1.5MV ≠MIc
≠25
≠20
≠15
≠10M
V
vDC IMF109 M§108 M§107 M§
[Fe/H]=0 [Fe/H]=≠2
QUASARS
time
≠0.5 0.0 0.5 1.0 1.5MV ≠MIc
≠25
≠20
≠15
≠10
MV
QUASARS
UC
Dda
taMKDP IMF109 M§108 M§107 M§
time
Jerabkova T., Kroupa P., Dabringhausen J., Hilker M., Bekki K., A&A, 2017, in press
QSO data: Dunlop+(1993),Dunlop+(2003),Souchay+(2015)high redshift quasars: Morltlock+(2011)
Also colours can be consistent with QSO!
dots/squares: 100 Myr, 500 Myr, 1 Gyr, 5 Gyr, 10 Gyr
RESULTS: MASS-TO-LIGHT RATIOS 13
100 101 102 103 104
time [Myr]
10≠4
10≠3
10≠2
10≠1
100
101
M/L
V
NO remnants10% remnants100% remnants
107 M§ 108 M§ 109 M§[Fe/H]=-2 M
BH
øvDC IMFSAL IMFCAN IMFMKDP IMF
100 101 102 103 104
time [Myr]
10≠4
10≠3
10≠2
10≠1
100
101
M/L
V
NO remnants10% remnants100% remnants
107 M§ 108 M§109 M§[Fe/H]=0 M
BH
øvDC IMFSAL IMFCAN IMFMKDP IMF
no degeneracies, t < 100 Myr
Jerabkova T., Kroupa P., Dabringhausen J., Hilker M., Bekki K., A&A, 2017, in press
SN kicks are not able to remove large fraction of BHs
See our paper (Jerabkova+2017)
and poster: The black hole retention fraction in star clusters (P2)
RESULTS: MASS-TO-LIGHT RATIOS 14
100 101 102 103 104
time [Myr]
10≠4
10≠3
10≠2
10≠1
100
101
M/L
V
NO remnants10% remnants100% remnants
107 M§ 108 M§ 109 M§[Fe/H]=-2 M
BH
øvDC IMFSAL IMFCAN IMFMKDP IMF
100 101 102 103 104
time [Myr]
10≠4
10≠3
10≠2
10≠1
100
101
M/L
V
NO remnants10% remnants100% remnants
107 M§ 108 M§109 M§[Fe/H]=0 M
BH
øvDC IMFSAL IMFCAN IMFMKDP IMF
no degeneracies, t < 100 Myr
Jerabkova T., Kroupa P., Dabringhausen J., Hilker M., Bekki K., A&A, 2017, in press
106 107 108
LV [LV§]
5
10
15
20
25
M/L
V
5 Gyr10 Gyr13 Gyr
[Fe/H]=-2vDC IMFSAL IMFMKDP IMF
-10.17 -12.67 -15.17MV [mag]
106 107 108
LV [LV§]
5
10
15
20
25
M/L
V
[Fe/H]= 0
-10.17 -12.67 -15.17MV [mag]
observations
Results are sensitive to [Fe/H]
SN kicks are not able to remove large fraction of BHs
See our paper (Jerabkova+2017)
and poster: The black hole retention fraction in star clusters (P2)
109, 108, 107M�
RESULTS: SUMMARY AND CONCLUSIONS 15
Jerabkova T., Kroupa P., Dabringhausen J., Hilker M., Bekki K., A&A, 2017, in press
1. Progenitors of UCDs and massive GCs are observable with JWST
2. For objects younger than 100 Myr we can constrain their IMF ( if we observe them)
3. Older objects suffer from degeneracies and constraining the IMF is more difficult
4. Some observed quasars have similar photometric properties as very young UCDs with top-heavy IMF (Are all quasars quasars?)
5. The kick retention fraction of stellar remnants is near to 100% for systems with birth masses larger than 107M�
In prep.: Similar analysis aiming at multiple populations in young GCsCan we disentangle different formation scenarios? What is the effect of binaries?See also: Bekki, Jerabkova, Kroupa, MNRAS, 2017 (variable IMF in GCs)and: Yan, Jerabkova, Kroupa, A&A, 2017 (systematic variation of the IMF in python - on Github)
RESULTS: REDSHIFTED SED 16
J and K filter cover similar wavelength range as F115W and F200W (NIRCam)
103 104 105 106 107
⁄ [A]
10≠33
10≠32
10≠31
10≠30
F‹[(e
rgs≠
1 cm≠
2 Hz≠
1 )]
z=3
z=6
z=9
top-heavy IMF8 Myr
Jfil
t.
Nfil
t.
Kfil
t.
8 Myr
MKD IMF
Marks et al. (2012)
103 104 105 106 107
⁄ [A]
z=3
z=6
z=9
canonical IMF
8 Myr
Jfil
t.
Nfil
t.
Kfil
t.
CAN IMF
N filter covers similar wavelength range as F1000W (MIRI)
Jerabkova T., Kroupa P., Dabringhausen J., Hilker M., Bekki K., A&A, 2017, in press
RESULTS: FORMATION AND WHERE TO LOOK 17
Jerabkova T., Kroupa P., Dabringhausen J., Hilker M., Bekki K., A&A, 2017, in press
The most massive clusters are near the centres of galaxies with high star formation rateFerrarese&Merritt (2002), Dabringhausen+(2012), Weidner+(2004), Randriamanakoto+(2013),Li+(2017)
Possible formation scenario
1. Formation of massive galaxies - large star formation rates (large densities, merging of proto-galactic gas clumps)
2. The most massive clusters are forming as monolithically collapsed in the deepest potential wells of these (decouple from gas when become stellar systems)
3. Merging proto-galaxies - many formed clusters ending up on orbits about the central galaxy
4. Under more benign conditions we expect to form stellar systems from mergers of star cluster complexes