Finding Dense Clouds From the 2MASS and GLIMPSE360 Data｜國立清華大學博碩士論文庫

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研究生：	葉則敬 Yeh, Cosmos C.
論文名稱：	Finding Dense Clouds From the 2MASS and GLIMPSE360 Data 利用2MASS與GLIMPSE360觀測數據尋找緻密星雲
指導教授：	呂聖元 Liu, Sheng-Yuan
口試委員:	陳文屏 Chen, Wen-Ping 陳惠茹 Chen, Huei-Ru 高見道弘 Michihiro Takami 呂聖元 Liu, Sheng-Yuan
學位類別：	碩士 Master
系所名稱：	理學院 - 天文研究所 Institute of Astronomy
論文出版年：	2012
畢業學年度：	100
語文別：	英文
論文頁數：	114
中文關鍵詞：	星際介質:分子雲、星際介質:消光、星際介質:紅外線暗星雲、色餘、光譜能量分佈擬合、2MASS計畫、GLIMPSE360計畫
外文關鍵詞：	ISM: molecular clouds, ISM: extinction, ISM: infrared dark clouds, color excess, SED fitting, 2MASS, GLIMPSE360
相關次數：	點閱：2 下載：0
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我們建立了一系列可以製作不同消光圖(Extinction map)的流程(Pipeline)。利用2MASS與GLIMPSE360計畫的觀測數據,我們可以使用不同方法製作消光圖。這些方法包含:恆星計數法(Star count method)、色餘法(Color excess method)、與光譜能量分佈擬合法(SED fitting method)。史匹哲太空望遠鏡在中紅外線波段的觀測可測量到視消光值(Visual extinction)AV∼100等(約等於柱密度9 × 10^22 cm^−2),使我們能夠從在缺乏明亮瀰散背景的狀況中找到緻密分子雲(Dense molecular cloud),例如紅外線暗星雲(Infrared dark cloud)等。GLIMPSE360計畫的高解析度可供我們研究整個銀河盤面的質量分佈,尺度可大至旋臂結構,小至單獨的星雲。
為了驗證我們的流程與各種方法的可行性,特別是首次使用的光譜能量分佈擬合法,我們針對接近銀河中心與銀河外部的兩個測試視野(Test field)製作並比較不同的消光圖。對於銀河外部測試視野,比較結果發現利用H − K近紅外線色餘法所製作的消光圖與光譜能量分佈擬合法所製作的消光圖極為相似。這兩種方法皆找出星雲的瀰散部份,其範圍約為視消光值AV∼0等到AV∼40等(柱密度∼3.6 × 10^22 cm^−2)。相反地,使用史匹哲數據的[3.6]−[4.5]色餘法可找出星雲核心的部分,其視消光值可高達AV∼100。我們也針對於銀河中心的測試視野進行類似比較。從比較中我們發現,利用H−K色餘法與光譜能量分佈擬合法製作的消光圖在高消光區域受到前景恆星(Foreground stars)的嚴重影響,但利用[3.6]−[4.5]色餘法所製作的消光圖卻可在紅外線暗星雲區域顯示出高消光值,此結果顯示[3.6]−[4.5]色餘法可被用來尋找銀河盤面的紅外線暗星雲。比較恆星密度分佈圖(Stellar density map)與消光圖可被用來找出只包含前景恆星的高消光區域。

We have established a pipeline that can generate various extinction maps. With the point source catalog from the 2MASS and GLIMPSE360 projects, we applied various methods such as star count, color excess, and SED fitting method for our extinction mapping. In particular observation in Spitzer mid-infrared bands could trace visual extinction up to AV∼100 mag (∼column densities of 9 × 10^22 cm^−2). Thus, the data allow the identification of dense molecular clouds, such as infrared dark clouds, in the absence of bright diffuse Galactic background emission. The high-spatial resolution achieved by the GLIMPSE360 project data allow us to investigate the mass distribution from Galactic size-scales (spiral structures) down to individual clouds for the entire Galactic plane.
To verify our approaches and pipeline, particularly the new SED fitting method, we compared extinction maps of our two test fields towards both the inner and outer Galaxy. For the field toward outer Galaxy, our extinction map derived from the H−K near-infrared color excess method resembles the map derived from the SED-fitting method. Both of these two methods trace diffuse parts of clouds with the AV ranging from 0 mag to 40 mag (∼3.6 × 10^22 cm^−2). In contrast, Spitzer [3.6]−[4.5] extinction map probes denser (AV up to ∼ 100 mag) clumps in the central region of the cloud. For the field toward the Galactic center, both our extinction maps generated by the H−K color excess method and that generated by the SED fitting method suffer from the contamination of foreground stars in high extinction regions. The comparison of the [3.6]−[4.5] extinction map to the Spitzer 8μm image infers that [3.6]−[4.5] color excess method is capable to outline high extinction features corresponding to infrared dark clouds in the Galactic plane. Comparing stellar density maps to our extinction maps is feasible to identify high extinction regions contain purely foreground stars.

1 Introduction    1
    1.1 The project scope......................... 2
    1.2 Tracing dense clouds by various approaches......................... 3
    1.3 Review of existing surveys......................... 6
2 Data Reductions and Analysis......................... 9
    2.1 The 2MASS data ......................... 10
    2.2 The GLIMPSE360 survey......................... 11
    2.3 Test fields for applying various extinction mapping......................... 12
3 Tracing Dense Clouds Without Bright Background Emissions......................... 15
    3.1 The interstellar extinction law......................... 16
    3.2 The star count method......................... 18
        3.2.1 Obtaining extinction values from evaluating stellar density......................... 19
        3.2.2 Deriving luminosity functions of the field......................... 22
        3.2.3 Star count extinction map in each band......................... 23
    3.3 The color excess method......................... 29
        3.3.1 Extinction determination of the color excesses method......................... 34
        3.3.2 The intrinsic color of background stars......................... 36
    3.4 The SED fitting method......................... 37
        3.4.1 The SED fitter......................... 38
        3.4.2 Validating the SED fitting method......................... 40
        3.4.3 Source selection for the SED fitting method......................... 53
4 The Smoothing Methods......................... 61
    4.1 The grid method......................... 62
    4.2 Gaussian smoothing method......................... 64
5 Discussions......................... 66
    5.1 Source selection and the sampling problem in various methods......................... 67
    5.2 The comparison of various extinction maps......................... 69
    5.3 Tracing IRDCs from various extinction methods......................... 70
    5.4 The uncertainty of the map......................... 76
        5.4.1 The uncertainty of the grid method......................... 77
        5.4.2 The uncertainty of the Gaussian smoothing method......................... 82
        5.4.3 The uncertainty of the SED fitting method......................... 86
6 Conclusions & Future Works......................... 89
    6.1 Conclusions......................... 89
    6.2 Future works......................... 90
        6.2.1 Tiling various extinction maps......................... 91
        6.2.2 Completing the extinction mapping with the entire GLIMPSE360 survey......................... 92
        6.2.3 Interstellar extinction law toward various galactic longitudes......................... 92
        6.2.4 Deep near-infrared observations......................... 93
        6.2.5 Further analyses......................... 94
Bibliography......................... 97
Appendices......................... 101
    A The main flow chart of our extinction mapping programs......................... 101
    B The pipeline of our star count method and catalog completeness evaluation......................... 103
    C The pipeline of our grid method......................... 105
    D The pipeline of Gaussian smoothed color excess maps......................... 107
    E The pipeline of our SED fitting method......................... 109
    F Analyses related to red clump stars......................... 111
    G Analyses after the χ2 deletion......................... 113

                                

[1] Alves, J. F., Lada, C. J., & Lada, E. A., 2001, Nature, 409, 159
[2] Bohlin, R. C., Savage, B. D., & Drake, J. F., 1978, ApJ, 224, 132
[3] Bok, B. J., 1937, The Distribution of Stars in Space (Chicago: Univ. of Chicago Press)
[4] Bok, B. J., & Cordwe, C. S., 1973, in molecules in the Galactic enviorn- ment, edited by M. A. Gordon and L. E. Snyder (Wiley, New York), p.53
[5] Cardelli et al. 1989, AJ, 97, 1099
[6] Chapman et al. 2009, ApJ, 690, 496
[7] Dickman, R. L. 1978, ApJ, 37, 407
[8] Dobashi et al. 2005, PASJ, 57, S1
[9] Dobashi, K. 2011, PASJ, 63, S1
[10] Drimmel, R., Cabrera-Lavers, A., & L ́opez-Corredoira, M., 2003, A&A, 409, 205
[11] Flaherty et al. 2007, ApJ, 663, 1069
[12] Frerking, M. A., Langer, W. D., & Neugebauer, G., 1982, ApJ, 260, 590
[13] Hekker, S., & Melendez, J. 2007, A&A, 475, 1003
[14] Henning, T. et al. 2010, A&A, 518, L95
[15] Hyland, A. R. 1980, in IAU Symp. 96, Infrared Astronomy, ed. C. D. Wynn-Williams & D. P. Cruikshank (Dordrecht: Reidel), 125
[16] Indebetouw et al. 2005, ApJ, 619, 931
[17] Jenkins, E. B., & Savage, D. B. 1974, ApJ, 187, 243
[18] Jiang et al. 2006, A&A, 446, 551
[19] Jones, T. J., Hyland, A. R., & Bailey, J. A., 1981, ApJ, 282, 675
[20] Kainulainen, J., Alves, J., Beuther, H., Henning, T., & Schuller, F., 2011, A&A, 536, A48
[21] Koornneef, T., 1983, A&A, 128, 84
[22] Kurucz, R., 1993, Kurucz CD-ROM No. 13, ATLAS9 Stellar Atmo- sphere Programs and 2 km/s Grid (Cambridge: SAO)
[23] Lada, C. J., Alves, J., & Lada, E. A., 1999, AJ, 512, 250
[24] Lada, C. J., Lada, E. A., Clemens, D. P, & Bally, J., 1994, ApJ, 429, 694
[25] Lilley, A. E., 1955, ApJ, 121, 559
[26] Lombardi, M., & Alves, J., 2001, A&A, 377, 1023
[27] Lombardi, M., Alves, J., & Lada, C. J. 2011, A&A, 535, A16
[28] Lombardi, M. 2009, A&A, 493, 735
[29] L ́opez-Corredoira, M., Cabrera-Lavers, A., Garzon, F., & Hammersley, P. L., 2002, A&A, 394, 883
[30] Lucas et al. 2008, MNRAS, 391, 136 98
[31] Lutz et al. 1996, A&A, 315, L269
[32] Mishenina, T. V., Bienaym ́e, O., Gorbaneva, T. I., et al., 2006, A&A, 456, 1109
[33] Molinari et al. 2010, A&A, 518, L100
[34] Pagani et al. 2004, A&A, 417, 605
[35] Rathborne, J. M., Simon, R., & Jackson, J. M. 2007, ApJ, 662, 1082
[36] Rhijn, P. J. van, 1929, Groningen Publ. 43
[37] Rieke, G. H., & Lebofsky, M. J. 1985, ApJ, 288, 618
[38] Robin, A. C., Reyl ́e, C., Derriere, S., & Picaud, S. 2003, A&A, 409, 523
[39] Robitaille, T. P., Whitney, B. A., Indebetouw, R., & Wood, K., 2007, ApJS, 169, 328
[40] Robitaille, T. P., Whitney, B. A., Indebetouw, R., Wood, K., & Denz- more, P. 2006, ApJS, 167, 256
[41] Rygl, K. L. J., Wyrowski, F., Schuller, F., & Menten, K. M., 2010, A&A, 515, A42
[42] Saguner, T., Munari, U., Fiorucci, M., & Vallenari, A., 2011, A&A, 527, A40
[43] Schuller et al. 2009, A&A, 504, 415
[44] Skrutskie et al. 2006, AJ, 131, 1163
[45] Takeda, Y., Sato, B., & Murata, D. 2008, PASJ, 60, 781
[46] Valentini, U., & Munari, U. 2010, A&A, 522, A79
[47] Weingartner, J. C., & Draine, B. T. 2001, ApJ, 548, 296
[48] Wolf, M., 1923, Astron. Nachr., 219, 109
[49] Zasowski et al. 2009, ApJ, 707, 510

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