 |
|
|
|
以作者查詢圖書館館藏 、以作者查詢臺灣博碩士 、以作者查詢全國書目 、勘誤回報 、線上人數：59 、訪客IP：3.149.234.141
姓名 張逸雯(Yi-Wen Chang) 查詢紙本館藏 畢業系所 天文研究所 論文名稱 A numerical simulation survey on the outflow from the Galactic center
(A numerical simulation survey on the outflow from the Galactic center)相關論文 檔案 [Endnote RIS 格式]
[相關文章]
[文章引用]
[完整記錄]
[館藏目錄]
[檢視]
- 本電子論文使用權限為同意立即開放。
- 已達開放權限電子全文僅授權使用者為學術研究之目的，進行個人非營利性質之檢索、閱讀、列印。
- 請遵守中華民國著作權法之相關規定，切勿任意重製、散佈、改作、轉貼、播送，以免觸法。
摘要(中) 在2010 的年尾，費米伽瑪射線空間望遠鏡在銀河的盤面上下各發現了一個巨
大的伽瑪射線結構，他們從銀河的中心向外延伸，約到達經度40、緯度50，長
得像兩個大型的泡泡。這樣的空間分佈，剛好跟在銀盤附近倫琴衛星估測到的
1.5 keV 波段X 射線圖以及幾年前威爾金森微波各向異性探測器的謎團有一定的
關聯性，所以我們認為這些現象應該是來自於相同的來源。關於這來源，雖然有
很多不同的猜測，但我們在這邊特別討論銀河中心的大質量黑洞不間斷的恆星捕
獲造成的結果。每當有捕獲現象發生，就會有極大的能量在銀河中心被釋放，產
生一個類似爆炸的現象，形成我們所觀測到的泡泡。
我們利用PLUTO(一個天文物理的程式)去模擬這個現象。在二維圓柱座標下設
定不同的初始條件去觀察這個泡泡的形成以及演化，例如用不同的能量或在不同
的時間間隔下去產生每個爆炸。同時也考慮當銀河盤面上的氣體分佈是指數遞減，
泡泡的演化隨著不同大氣標高變化。
我們首先比較不同能量下，發生一次爆炸的例子(有相同的大氣標高)。泡泡
的側邊在能量小的例子會發展的比較遠，但是擾動也比較小。當能量比較大的時
候，他可以輕易的打穿盤面的大氣，向上發展，但是側邊會被限制，大約只能到
達三倍大氣標高的距離。
接著我們比較單次以及多次爆炸的例子，雖然他們有相同的總能量但是外表
卻差很多。多次爆炸的例子側邊的發展也被限制，但是泡泡的內部比較混亂，而
內部混亂的結構會隨著時間間隔的拉長而變得更亂。模擬所產生的X 射線圖顯示
了在多次爆炸的情況下在較低緯的地方，泡泡有比較厚的結構。我們同時也把他
來拿和倫琴衛星的數據做比較。摘要(英) In the second half of 2010, Fermi satellite discovered two giant gamma ray
bubbles above and below our Galactic plane in the direction of the Galactic center.
The bubbles extended 50 degrees in Galactic latitude and 40 degrees in longitude.
The spatial distributions correlated with the ROSAT X-ray map at 1.5 keV and the
WMAP haze near the Galactic plane. Among many possible origins of the bubbles,
we are particular interested in the scenario that stars are repeatedly captured by the
supermassive black hole located at the Galactic center. At each capture, a huge
amount of energy is release and causes a massive expansion or outflow that forms
the bubbles.
We adopt the astro-hydrodynamic code PLUTO to study this phenomenon. We
carry out 2D (cylindrical coordinates) numerical survey on the formation and
evolution of the bubbles under different conditions, such as different energy release
at each capture and different time intervals between captures. We also consider the
effect of different assumed scale heights of the Galactic gaseous disk.
When we compare different single capture cases (with same scale height), we
learn that the shape of the bubble from small energy release is rounder and
extended further in the lateral direction than the one from large energy release, but
the perturbation is weaker. When the energy release is large, the bubble can easily
penetrate the disk, but the lateral extend is restricted to about three times the scale
heights.
The morphology of a single capture case and a repeated captures case with the
same total energy is significantly different. The repeated captures case has lesser
lateral evolution and a lot more turbulent interior. Moreover, the turbulent level
increases when the interval between captures decreases. The X-ray maps from
simulations show that the repeated captures cases have slightly thick lower bubble
edge than the single capture cases. We also compare the maps with ROSAT data.關鍵字(中) ★ 數值模擬
★ 費米泡泡
★ 銀河中心
★ 流體力學關鍵字(英) ★ Simulation
★ Fermi Bubbles
★ PLUTO code
★ Galactic center
★ HD論文目次 中文摘要 ......................................................................................................................... i
Abstract ......................................................................................................................... iii
致謝 ............................................................................................................................... v
Table of contents .......................................................................................................... vii
List of figures ............................................................................................................... viii
List of tables ................................................................................................................... x
Chapter 1 Introduction ............................................................................................... 1
Chapter 2 Code and Simulation .................................................................................. 9
2-1 PLUTO ............................................................................................................ 9
2-1-1 Algorithm ........................................................................................... 9
2-2 Boundary and initial conditions .................................................................. 11
2-2-1 Units................................................................................................. 12
2-3 Tests of the program ................................................................................... 14
2-3-1 2D and 3D comparison .................................................................... 14
2-3-2 Grid size dependent......................................................................... 15
2-3-3 Supernova remnant ......................................................................... 16
2-3-4 Comparison with analytic solution .................................................. 17
Chapter 3 Result ........................................................................................................ 19
3-1 Standard case .............................................................................................. 19
3-2 Bubble evolution with different energy ...................................................... 26
3-3 Bubble evolution with different scale heights ............................................ 33
3-4 Repeated captures with different frequency .............................................. 39
3-4-1 Single capture compare with repeated captures ............................ 52
3-5 X-ray map .................................................................................................... 54
Chapter 4 Summary and discussion .......................................................................... 57
Appendix A ................................................................................................................... 62
Appendix B ................................................................................................................... 65
References .................................................................................................................... 68參考文獻 Alexander, T. 2005. “Stellar processes near the massive black hole in the Galactic
center”, PhR, 419, 65
Colella, P., Woodward, P. R. 1984. “The Piecewise Parabolic Method (PPM) for
Gas-Dynamical Simulations”, J. Comput. Phys., 54, 174
Chang, C. K., Ko, C. M., & Peng, T. H. 2010. “The Information of the Milky Way From
Two Micron All Sky Survey Whole Sky Star Count: The Luminosity Function”,
ApJ, 724, 182.
Cheng, K. S., Chernyshov, D. O., Dogiel, V. A., et al. 2011. “Origin of the Fermi bubble”,
ApJ, 731, L17.
Chernyshov, D. O., Cheng, K. S., Dogiel, V. A., et al. 2010. “Restrictions on the
Injection Energy of Positrons Annihilating near the Galactic Center”, MNRAS, 403,
817
Chernyshov, D. O., Cheng, K. S., Dogiel, V. A., et al. 2011. “Particle acceleration and
the origin of gamma-ray emission from Fermi Bubbles”, arXiv:1109.2619
Chang, C. K., Ko, C. M., & Peng, T. H. 2011. “Information on the Milky Way from the
Two Micron All Sky Survey Whole Sky Star Count: The Structure
Parameters”, ApJ, 740, 34.
Crocker, R. M., Aharonian, F. 2011. “Fermi Bubbles: Giant, Multibillion-Year-Old
Reservoirs of Galactic Center Cosmic Rays”, PRL, 106, 101102
Cheng, K. S., Chernyshov, D. O., Dogiel, V. A., et al. 2012. “The Fermi Bubble as a
Source of Cosmic Rays in the Energy Range> 1015 eV”, ApJ, 746, 116.
Carretti, E., Crocker, R. M., Staveley-Smith, L., et al. 2013. “Giant magnetized outflows
from the centre of the Milky Way”, Nature, 493, 66-69.
Dogiel, V., Cheng, K. S., Chernyshov, D., et al. 2009a. “Origin of 6.4 keV line emission
from molecular clouds in the galactic center”, PASJ, 61, 901.
Dogiel, V., Chernyshov, D., Yuasa, T., et al. 2009b. “Particle Propagation in the Galactic
Center and Spatial Distribution of Non-Thermal X-Rays”, PASJ, 61, 1093.
Dogiel, V., Chernyshov, D., Yuasa, T., et al. 2009c. “Origin of Thermal and
Non-Thermal Hard X-ray Emission from the Galactic Center” PASJ, 61, 1099
Dobler, G., Finkbeiner, D. P., Cholis, I., Slatyer, T., & Weiner, N. 2010. “The Fermi haze:
a gamma-ray counterpart to the microwave haze”, ApJ, 717, 825.
Draine, B. T. 2011. “Physics of the interstellar and intergalactic medium” (Princeton,
NJ: Princeton Univ. Press)
Ferrière, Katia M. 2001. “The interstellar environment of our galaxy”, RMP, 73
Finkbeiner, A. 2012. “Galaxy formation: The new Milky Way”, Nature, 490, 24-27
Genzel, R., Schödel, R., Ott, T., et al. 2003. “Near-infrared flares from accreting gas
around the supermassive black hole at the Galactic Centre”, Nature, 425, 934-93.
Ghez, A. M., Duchêne, G., Matthews, K., et al. 2003. “The first measurement of
spectral lines in a short-period star bound to the Galaxy’s central black hole: a
paradox of youth”, AJ, 586, L127-131.
Goldwurm, A. 2007. “High energy activity of the super-massive black hole at the
Galactic Center”, Comptes Rendus Physique, 8, 35-44.
Gillessen, S., Genzel, R., Fritz, T. K., et al. 2011. “A gas cloud on its way towards the
supermassive black hole at the Galactic Centre”, Nature, 481, 51-54.
Guo, F., Mathews, W. G., Dobler, G., & Oh, S. P. 2012. “The Fermi Bubbles. II. The
Potential Roles of Viscosity and Cosmic-Ray Diffusion in Jet Models”, ApJ, 756, 182.
Mignone, A., Bodo, G., Massaglia, S., et al. 2007. “PLUTO: a numerical code for
computational astrophysics”, ApJ, 170, 228.
Michelson, P. F., Atwood, W. B., & Ritz, S. 2010. “Fermi Gamma-ray Space Telescope:
high-energy results from the first year”, Rep. Prog. Phys., 73, 074901.
Roe, P. L. 1981. “Approximate Riemann solvers, parameter vectors, and difference
schemes”, J. Comput. Phys., 43, 357-372
Snowden, S. L., Egger, R., Freyberg, M. J., et al. 1997. “ROSAT Survey Diffuse X-Ray
Background Maps. II.” ApJ, 485, 125.
Su, M., Slatyer, T. R., Finkbeiner, D.P. 2010. “Giant Gamma-ray Bubbles from Fermi
-LAT: Active Galactic Nucleus Activity or Bipolar Galactic Wind?”, ApJ, 724, 1044
Schartmann, M., Burkert, A., Alig, C., et al. 2012. “Simulations of the origin and fate
of the Galactic Center cloud G2”, AJ, 755, 155.指導教授 高仲明(Chung-Ming Ko) 審核日期 2013-7-10 推文 plurk
funp
live
udn
HD
myshare
netvibes
friend
youpush
delicious
baidu
網路書籤 Google bookmarks
del.icio.us
hemidemi
facebook
twitter
google
reddit