Copyright by Athena Ranice Stacy 2011 - The University of Texas at ...

More documents

Recommendations

Info

Table of Contents Acknowledgments v Abstract vi List of Tables xii List of Figures xiii Chapter 1. Introduction 1 1.1 Motivation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 1.2 Relation to Previous Work . . . . . . . . . . . . . . . . . . . . 3 1.3 Outline . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5 Chapter 2. Formation of Binaries and Small Multiple Systems 8 2.1 Overview . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8 2.2 Physical Ingredients . . . . . . . . . . . . . . . . . . . . . . . . 11 2.2.1 Protostellar accretion . . . . . . . . . . . . . . . . . . . 11 2.2.2 Protostellar feedback effects . . . . . . . . . . . . . . . . 12 2.2.3 Chemistry, heating and cooling . . . . . . . . . . . . . . 14 2.3 Numerical Methodology . . . . . . . . . . . . . . . . . . . . . . 15 2.3.1 Initial setup . . . . . . . . . . . . . . . . . . . . . . . . 15 2.3.2 Sink particle creation . . . . . . . . . . . . . . . . . . . 17 2.4 Results . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21 2.4.1 Initial runaway collapse . . . . . . . . . . . . . . . . . . 21 2.4.2 Protostellar accretion . . . . . . . . . . . . . . . . . . . 25 2.4.2.1 Disk formation . . . . . . . . . . . . . . . . . . 25 2.4.2.2 Angular momentum evolution . . . . . . . . . . 32 2.4.2.3 Binary and multiple formation . . . . . . . . . . 34 2.4.2.4 Accretion rate . . . . . . . . . . . . . . . . . . . 36 viii
2.4.2.5 Thermodynamics of accretion flow . . . . . . . 39 2.4.2.6 Feedback . . . . . . . . . . . . . . . . . . . . . 42 2.5 Parameter Sensitivity . . . . . . . . . . . . . . . . . . . . . . . 46 2.6 Summary and Discussion . . . . . . . . . . . . . . . . . . . . . 48 Chapter 3. Mass Growth Under Protostellar Feedback 54 3.1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . 54 3.2 Numerical Methodology . . . . . . . . . . . . . . . . . . . . . . 57 3.2.1 Initial Setup . . . . . . . . . . . . . . . . . . . . . . . . 57 3.2.2 Chemistry, Heating, and Cooling . . . . . . . . . . . . . 58 3.2.3 Sink Particle Method . . . . . . . . . . . . . . . . . . . 59 3.2.4 Ray-tracing Scheme . . . . . . . . . . . . . . . . . . . . 61 3.2.5 Photoionization and Heating . . . . . . . . . . . . . . . 63 3.2.6 Protostellar evolution model . . . . . . . . . . . . . . . 64 3.3 Results . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 70 3.3.1 Disk Evolution . . . . . . . . . . . . . . . . . . . . . . . 70 3.3.1.1 No-feedback case . . . . . . . . . . . . . . . . . 70 3.3.1.2 With-feedback case . . . . . . . . . . . . . . . . 76 3.3.2 Fragmentation . . . . . . . . . . . . . . . . . . . . . . . 77 3.3.3 Ionization Front Evolution . . . . . . . . . . . . . . . . 82 3.3.4 Protostellar Mass Growth . . . . . . . . . . . . . . . . . 86 3.4 Summary and Discussion . . . . . . . . . . . . . . . . . . . . . 89 Chapter 4. Rotation Speed of Population III Stars 94 4.1 Overview . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 94 4.2 Numerical Methodology . . . . . . . . . . . . . . . . . . . . . . 98 4.2.1 Initial Setup . . . . . . . . . . . . . . . . . . . . . . . . 98 4.2.2 Chemistry, heating, and cooling . . . . . . . . . . . . . . 100 4.2.3 Sink Particle Method . . . . . . . . . . . . . . . . . . . 100 4.3 Results . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 102 4.3.1 Sink Growth and Angular Momentum . . . . . . . . . . 102 4.3.1.1 Accretion Rate . . . . . . . . . . . . . . . . . . 102 4.3.1.2 Angular Momentum . . . . . . . . . . . . . . . 104 ix
Page 1 and 2: Copyright by Athena Ranice Stacy 20
Page 3 and 4: New Insights into Primordial Star F
Page 5 and 6: Acknowledgments I first want to giv
Page 7: angular momentum to rotate at nearl
Page 11 and 12: Chapter 7. Outlook 177 Bibliography
Page 13 and 14: List of Figures 2.1 Density project
Page 15 and 16: 1.1 Motivation Chapter 1 Introducti
Page 17 and 18: leaving behind a neutron star or bl
Page 19 and 20: describe studies that have attempte
Page 21 and 22: CRs may therefore provide a pathway
Page 23 and 24: expected that some of the gas withi
Page 25 and 26: our numerical methodology in Chapte
Page 27 and 28: scattering is the major source of o
Page 29 and 30: portance. The reaction rates for an
Page 31 and 32: The size of the refinement levels h
Page 33 and 34: the sink a temperature and pressure
Page 35 and 36: same time, such as the fragments in
Page 37 and 38: Figure 2.2: Physical state of the c
Page 39 and 40: 2.4.2 Protostellar accretion 2.4.2.
Page 41 and 42: Despite some amount of rotational s
Page 43 and 44: Figure 2.6: Velocity field of the c
Page 45 and 46: Figure 2.7: Disk mass vs. time sinc
Page 47 and 48: Figure 2.8: Angular momentum struct
Page 49 and 50: sink tform [yr] Mfinal [M⊙] rinit
Page 51 and 52: sink (∼ 4 M⊙) that merged with
Page 53 and 54: actual final mass of the star is li
Page 55 and 56: the average temperature of all part
Page 57 and 58: disk accretion onto a primordial pr
Page 59 and 60:
Figure 2.12: Impact of feedback on
Page 61 and 62:
Figure 2.13: Comparison of specific
Page 63 and 64:
the central core, eventually compri
Page 65 and 66:
extending our simulation to later t
Page 67 and 68:
that such a non-primordial origin t
Page 69 and 70:
impose an upper mass limit to Pop I
Page 71 and 72:
we use a ray-tracing scheme to foll
Page 73 and 74:
3.2.3 Sink Particle Method When an
Page 75 and 76:
convenient way to directly measure
Page 77 and 78:
where the sum now extends from the
Page 79 and 80:
Figure 3.1: Evolution of various pr
Page 81 and 82:
ased on the prescription of Omukai
Page 83 and 84:
ate found at late times in our ‘n
Page 85 and 86:
Figure 3.2: Evolution of various di
Page 87 and 88:
Figure 3.3: Evolution of disk mass
Page 89 and 90:
Figure 3.4: Temperature versus numb
Page 91 and 92:
disk mass is able to level off in d
Page 93 and 94:
Figure 3.6: Projected density and t
Page 95 and 96:
onto the disk. The numerical experi
Page 97 and 98:
that the I-front expands as an hour
Page 99 and 100:
Figure 3.8: Evolution of various H
Page 101 and 102:
˙ M∗ = 3πΣν, (3.18) where ν
Page 103 and 104:
the discrete nature of the gas part
Page 105 and 106:
stars. We also note that, despite t
Page 107 and 108:
current computational limits. If ra
Page 109 and 110:
the deaths of massive stars (see Wo
Page 111 and 112:
It is apparent that the angular mom
Page 113 and 114:
h = 0.7. To accelerate structure fo
Page 115 and 116:
acc = Lres 50 AU, where: Lres 0.5
Page 117 and 118:
years, up to several dynamical time
Page 119 and 120:
sp = GM∗ c2 , (4.1) s where cs is
Page 121 and 122:
Figure 4.2: Left: Angular momentum
Page 123 and 124:
through the disk, and the disk is e
Page 125 and 126:
steadily grows for the rest of the
Page 127 and 128:
Fig. 4.5 shows these timescales for
Page 129 and 130:
sink B. Once on the MS, the sink A
Page 131 and 132:
Figure 4.6: Evolution of stellar ro
Page 133 and 134:
sink M∗(5000 yr) [M⊙] M∗(10 5
Page 135 and 136:
present here, particularly if the s
Page 137 and 138:
the stars grow to larger masses (se
Page 139 and 140:
Here, Σ is the disk surface densit
Page 141 and 142:
which has already detected GRBs at
Page 143 and 144:
M⊙. They find that the specific a
Page 145 and 146:
are initialized at high z with smal
Page 147 and 148:
M⊙, where Nneigh 32 is the typic
Page 149 and 150:
Figure 5.1: Top panels: Effective v
Page 151 and 152:
Figure 5.2: Effect of relative stre
Page 153 and 154:
Using cs ∝ T 1/2 results in ρ
Page 155 and 156:
Figure 5.4: Evolution of gas proper
Page 157 and 158:
a much smaller contribution from <
Page 159 and 160:
abundances of HD, which also acts a
Page 161 and 162:
first stars had very short lifetime
Page 163 and 164:
of star-forming material. Here we t
Page 165 and 166:
star formation, they found CR energ
Page 167 and 168:
The GZK cutoff applies only to thos
Page 169 and 170:
and virialization redshift zvir = 2
Page 171 and 172:
and undergoes free-fall collapse. I
Page 173 and 174:
β = 1 − −2 1/2 ɛ + 1 mHc2
Page 175 and 176:
and where ΓCR(D) = 5 × 10 −29 e
Page 177 and 178:
Figure 6.2: Thermal evolution of pr
Page 179 and 180:
Figure 6.3: Minimum temperature rea
Page 181 and 182:
Figure 6.4: Thermal evolution of pr
Page 183 and 184:
The CR energy density can now be es
Page 185 and 186:
2007). When considering realistic c
Page 187 and 188:
6.3.5 Fragmentation scale As is evi
Page 189 and 190:
2006). This decrease in fragmentati
Page 191 and 192:
Chapter 7 Outlook Our understanding
Page 193 and 194:
that Pop III stars likely experienc
Page 195 and 196:
to be part of an area of scientific
Page 197 and 198:
Barkana, R. and Loeb, A. (2001). In
Page 199 and 200:
Bromm, V., Kudritzki, R. P., and Lo
Page 201 and 202:
Daigne, F., Olive, K. A., Silk, J.,
Page 203 and 204:
Gao, L., White, S. D. M., Jenkins,
Page 205 and 206:
Heger, A., Woosley, S. E., and Spru
Page 207 and 208:
Kratter, K. M. and Murray-Clay, R.
Page 209 and 210:
Machida, M. N., Omukai, K., Matsumo
Page 211 and 212:
Navarro, J. F. and White, S. D. M.
Page 213 and 214:
Rollinde, E., Vangioni, E., and Oli
Page 215 and 216:
Simon, M., Ghez, A. M., Leinert, C.
Page 217 and 218:
Tanvir, N. R., Fox, D. B., Levan, A
Page 219 and 220:
Rays, volume 576 of Lecture Notes i
Page 221 and 222:
Zatsepin, G. T. and Kuz’min, V. A
show all

Copyright by Athena Ranice Stacy 2011 - The University of Texas at ...

You also want an ePaper? Increase the reach of your titles

Delete template?

Save as template?