2009.4 ~ 2010.3

The astrophysics and cosmology group of Korea Institute for Advanced Study consists of Prof. Changbom Park, and three research fellows. Prof. Park organized a Korean Scientist Group (KSG) to participate in the new international consortium for the Sloan Digital Sky Survey III (SDSS-III). This survey is a legacy survey of the previous SDSS survey. KIAS, in partnership with ARCSEC of Sejong University, has joined the SDSS-III in March, 2008. The new survey will continue through 2014, and consists of the massive survey of high-redshift luminous red galaxies (BOSS), structure, dynamics and chemical evolution study of the Milky Way Galaxy (SEGUE-II, APOGEE), and the search for exoplanets (MARVELS). The outputs of the Sloan Digital Sky Survey (SDSS) and SDSS-III are giving us a special opportunity to make major findings in the fields of cosmology and structure formation.

Individual members of the astrophysics and cosmology group have been active in his/her research in 2008. Prof. Park, in collaboration with J. Richard Gott of Princeton university and Dr. Juhan Kim of Kyung-Hee University made a large cosmological N-body simulation that ran 70 billion CDM particles in a box with side length of about 9300 Mpcs. This simulation is named 'The Horizon Run', and will be used to simulated the Luminous Red Galaxies that will be observed by the upcoming SDSS-III survey out to redshift z≈0.7. Prof. Park is also studying the properties of galaxies and their correlations in great details. Prof. Park in collaboration with Dr. Yun-Young Choi of Sejong University studied the effects of environments, namely, the nearest neighbor galaxy and large-scale density, on the nuclear activity of galaxies using the SDSS DR7 final data. They also measured the topology of the large-scale distribution of the Main galaxies, and found that galaxy clustering topology depends also on morphology and color and that none of the currently popular galaxy formation models reproduces the ket aspects of the observed topology.

Pravabati Chingangbam worked on simulation of non-Gaussian CMB maps and using them to measure the non-Gaussian deviations encoded in the Minkowski Functionals (MF's), along with prof. Changbom Park. She developed a new code which can measure MF's accurately from maps that contain observational contaminants and incomplete sky due to masked regions. They studied the statistical nature, sensitivity and distinctions between non-Gaussian deviations arising from quadratic and cubic order primordial perturbations. They also proposed new statistical tests that can clearly distinguish $f_{NL}$ and $g_{NL}$ type non-Gaussianities. Further, the effects of experimental noise, beam patterns and masking of galaxy and point sources on the MF's is studied. The effect of the contaminants is found to be weak and hence the MF's are very useful tools to look for non-Gaussianity in the real observational data. Work on comparing the theoretical predictions with real data is under way.

On the inflation model building side she has studied the generation of tensor perturbations from models that have transient break of slow roll. It is found the break of slow roll can lead to the tensor-to-scalar ratio being much larger than one briefly and this leads to a sharp significant rise of angular power of $B$ modes of polarization on large scales. She has also studied inflation due to Yang-Mills gauge field with quartic coupling living on extra dimensions, which leads to dynamical shrinking of the extra dimensions. It is found that gauge field fluctuations do not destabilize spoil the attractive features of this scenario.

Dr. Graziano Rossi measured the clustering of hot and cold patches in the microwave background sky from the WMAP five-year data, and found significant differences from the simplest Gaussian-based prediction. These results were interpreted in the context of primordial non-Gaussianity, although other plausible explanations for the detected discrepancies were provided.

Dr. Graziano Rossi, Dr. Prava Chingangbam and Prof. Park have extended the statistics of the excursion sets to models with local primordial non-Gaussianity, and used simulated non-Gaussian maps to confirm their analytic predictions.

Dr. Graziano Rossi and Prof. Park have proposed a new method to recover unbiased distributions and scaling relations from photometric redshift surveys, and exemplified the deconvolution technique using a sample of early-type galaxies from the SDSS DR6. They found that by using only 10% of the spectroscopic training set it is possible to reconstruct accurately galaxy scaling relations. Dr. Graziano Rossi has also shown that a convolution technique is equivalent to a deconvolution one, and what additional information photometric redshift algorithms must output so that they can be used to study galaxy scaling relations.

Dr. Graziano Rossi and Prof. Park have started a new project on LSS topology, with the goal of constraining cosmological parameters with the next generation of galaxy surveys.

Dr. Jaswant Kumar has joined KIAS astrophysics group in January 2010. I have been working on the Semi-Analytic modelling of the formation and evolution of galaxies in the Universe. He has also been looking at the fractal nature of large scale structures as obtained from Sloan Digital Sky Survey.

Publication (저술)

  1. Lutgens, F. K., Tarbuck, E. J. 저, 김경렬, 김동희, 박창범, 전종갑, 조문섭 역, 지구시스템의 이해 (Foundations of Earth Science 5th ed.), 박학사, 2009

Publication (non-SCI)

  1. 박창범, 양홍진, "고구려의 고분 벽화 별자리와 천문체계", 『한국과학사학회지』, 제31권, 제1호, 1-45 (2009)

Publication (SCI)

  1. Kim, J., Park, Changbom, Gott, J. R., & Dubinski, J., The Horizon Run N-Body Simulation: Baryon Acoustic Oscillations and Topology of Large-scale Structure of the Universe, 2009, ApJ, 701, 1547 (Aug. 2009)
  2. Hwang, H. S., & Park, Changbom, Evidence for Morphology and Luminosity Transformation of Galaxies at High Redshifts, 2007, ApJ, 700, 791 (July 2009)
  3. Park, Changbom, & Hwang, H.-S., Interactions of Galaxies in the Galaxy Cluster Environment, 2009, ApJ, 699, 1595 (Jul. 2009)
  4. Abazajian, K. N. et al., The Seventh Data Release of the Sloan Digital Sky Survey, 2009, ApJS, 182, 543 (Jun. 2009)
  5. Cho, J., & Park, Changbom, Internal Extinction in the Sloan Digital Sky Survey Late-Type Galaxies, 2009, ApJ, 693, 1045 (Mar. 2009)
  6. Park, Changbom, & Choi, Y.-Y., Combined Effects of Galaxy Interactions and Large-Scale Environment on Galaxy Properties, 2009, ApJ, 691, 1828 (Feb. 2009)
  7. Lee, J. H., Lee, M. G., Park, C. and Choi, Y.-Y., The nature of the Sloan Digital Sky Survey galaxies in various classes based on morphology, colour and spectral features - II. Multi-wavelength properties, 2010, ApJ, 401, 1804
  8. Wang, Y., Park, C., Yang, X., Choi, Y.-Y., and Chen, X., Alignments of Group Galaxies with Neighboring Groups, 2009, ApJ, 703, 951
  9. Choi, Y.-Y., Woo, J.-H., and Park, C., Environmental Dependence of Active Galactic Nucleus Activity. I. The Effects of Host Galaxy, 2009, ApJ, 703, 951
  10. Gott, J. R., Choi, Y.-Y., Park, C., and Kim, J., Three-Dimensional Genus Topology of Luminous Red Galaxies, 2009, ApJ, 6 95L, 45
  11. Sheth, R. K. and Rossi, G. Convolution and deconvolution based estimates of galaxy scaling relations from photometric redshift surveys, 2009, MNRAS, 119
  12. Rossi, R., Sheth, R. K., and Park, C., Reconstructing galaxy fundamental distributions and scaling relations from photometric redshift surveys. Applications to the SDSS early-type sample, 2009, MNRAS, 401, 666
  13. Rossi, G., Sheth, R. K., C. Park, and Hernandez-Monteagudo, C., Non-Gaussian distribution and clustering of hot and cold pixels in the WMAP five-year sky, 2009, MNRAS, 399, 304
  14. Pravabati, C., Kihara, H., and Nitta, M., Gauge symmetry breaking in ten-dimensional Yang-Mills theory dynamically compactified on S6, 2009, PRD, accepted, hep-th/0912.3128.
  15. Pravabati, C and Park, C., Statistical nature of non-Gaussianity from cubic order primordial perturbations: CMB map simulations and genus statistic, 2009, JCAP, 12, 019.
  16. Jain, R. K., Pravabati, C., Sriramkumar, L., and Souradeep, T., The tensor-to-scalar ratio in punctuated inflation, 2009, PRD, submitted, astro-ph/0904.2518.
  17. Hernandez-Toledo, Vazquez-Mata, J. A., Martinez-Vazquez, Martinez, L. A., Choi, Y.-Y., & Park, Changbom, The UNAM-KIAS Catalog of Isolated Galaxies, 2009, ApJ, in press
  18. Wang, Y., Park, Changbom; Yang, X., Choi, Y.-Y., & Chen, X., Alignment between the host and the nearest neighbor Groups, 2009, MNRAS, submitted
  19. Park, Hyunbae, Kim, J., & Park, Changbom, Gravitational Potential Environment of Galaxies. I. Simulation, 2010, ApJ, 713, in press

Publication (Proceedings)

  1. G. Rossi, P. Chingangbam and C. Park, Excursion Set Statisics with Primordial non-Gaussianity, Journal of the Korean Physical Society, 2010, Proceedings of the ``11th Italian-Korean Symposium on Relativistic Astrophysics''

Presentations at Meetings

  1. G. Rossi, Mapping the Future in Cosmology: from Photo-zs to Non-Gaussianity, Shanghai, China, SHAO Colloquium, (Invited) March 18, 2009
  2. G. Rossi, Science Prospects over the Next Decade: New Observational Windows, SNU, Seoul, SNU Colloquium (Invited), March 19, 2009
  3. G. Rossi, C. Park, H.B. Ann and Y.Y. Choi, Disk Galaxy Rotation and Satellite Kinematics: Ancillary Science for BOSS `` Galaxy evolution and enviroment'', Kuala Lumpur, Malaysia, March 29 - April 4, 2009
  4. Park, C., LAMOST and its Sciences, LAMOST Meeting, KIAA, Beijing, China, Apr. 13-17, 2009 (Invited talk)
  5. 한두환(발표자), 박창범, 최윤영, 박명구, Properties of Type Ia Supernova Host Galaxies in the SDSS, 한국천문학회, 국립과천과학관, Apr. 30, 2009
  6. 박창범, 은하의 생성과 진화에 얽힌 의문, Open KIAS Summer Institute, 평창, Aug. 19-23, 2009
  7. Park, C., Topology of Large Scale Structure as a Cosmic Ruler, Extended Workshop on DM, LHC, and Cosmology, The KIAS-KAIST-YITP Joint Worshop, KIAS international conference hall, Aug. 28, 2009
  8. G. Rossi, CMB Clustering statistics in models with primordial local non-Gaussianity, KIAS, Seoul, KIAS-KAIST-YITP Joint Extended Workshop on DM, LHC and Cosmology, August 28, 2009
  9. G. Rossi, Peak statistics in the WMAP 5-yr sky, Cosmo International Conference on Particle Physics and Cosmology, COSMO09, Geneva, Swiss, September 14-18, 2009
  10. 박창범, 전통시대 천문현상 관측대로서의 첨성대의 특징과 영향, 첨성대 대토론회(역사, 종교, 천문학사, 천문학), KAIST, Sep. 24, 2009
  11. 박창범, 우주거대구조와 천체의 기원, 한림심포지움: 거대망원경과 한국천문학의 새로운 도약, 롯데호텔, Sep. 29-30, 2009
  12. 최윤영(발표자), 박창범, 우종학, Environmental Dependence of Active Galatic Activity II. The Effects of Galaxy Interation, 한국천문학회, 평창, Oct. 8-9, 2009
  13. 이준협(발표자), 이명균, 박창범, 최윤영, Environments of the SDSS Galaxies divided into Fine Classes, 한국천문학회, 평창, Oct. 8-9, 2009
  14. 박창범, Cosmological N-body Simulation of Cosmic Structure Formation, 계산과학공학회, COEX, Oct. 12-13, 2009
  15. 박창범, 경주 첨성대, 소남천문학사연구소 심포지움, 세종대왕기념관, Nov. 6, 2009
  16. Park, C., Topology of Large-Scale Structure Traced by Different Types of Galaxies, The 1st Galileo-Xu Guangqi Meeting, shanghai, China, Oct. 26-30, 2009
  17. G. Rossi, Cosmological implications of non-Gaussianity, Sogang University, Seoul, Korea, 11th Italian-Korean Symposium on Relativistic Astrophysics 'The Sun, the Stars, the Universe and General Relativity' (Invited), November 2, 2009
  18. Park, C., Galaxy Clustering Topology : Constraints on Galaxy Formation Models and Cosmological Parameters, The CosPA 2009 Meeting, Melbourne, Australia, Nov. 18-20, 2009
  19. G. Rossi, Primordial non-Gaussianity: CMB clustering statistics and large-scale structure implications, University of Melbourne, Melbourne, Australia, CosPA 2009, Symposium on Cosmology and Particle Astrophysics, November 18, 2009
  20. G. Rossi, Primordial non-Gaussianity and Distance Errors in Cosmology, AAO Sydney, Australia, Seminar, November 23, 2009
  21. Park. C., Environmental Effects on Galaxies, Japan-Korea Science Seminar 2009, Hiraizumi, Japan, Nov. 25-28, 2009
  22. G. Rossi, Convolution and deconvolution based estimates of galaxy scaling relations from photometric redshift surveys, Hiraizumi, Japan, JAPAN-KOREA SEMINAR 2009 Galaxy Build-Up Across Cosmic Ages and Environments, November 26, 2009
  23. 박창범, 경주 첨성대의 특징과 기능, 한국의 국보급 천문유물 워크숍, 충북대학교, Dec. 28, 2009
  24. 박창범, Large Scale Structures of the Universe, 2010 KIAS-SNU Physics Winter Camp, 평창, Jan. 31- Feb. 7, 2010
  25. 박창범, Cosmology: Large-scale structure & Cosmic Background Radiation, 천문학 및 천체물리학의 제 문제, KIAS, Feb. 9-10, 2010