The astrophysics and cosmology group of Korea Institute for Advanced Study consists of prof. Changbom Park, research prof. Juhan Kim, two assistant professors, and four research fellows. Prof. Park organized a Korean Scientist Group (KSG) to participate in the Sloan Digital Sky Survey III that will continue through 2014. In December 15, 2010 Prof. Park became the director of the new KIAS computer center, Center for Advanced Computation (KIAS CAC). The newest clusters of KIAS CAC include the GPU cluster system with 96 GPUs with a peak performance of 49 Tflops. The center consists of a director, 6 professors, 2 research professors, and 4 supporting staffs.

Prof. Juhan Kim together with a student Jihye Shin is implementing gas dynamics in the GOTPM code to study the galaxy formation in the cosmological context. The smoothed particle hydrodynamics algorithm is being adopted and a new approach to simulating the star formation, supernova feedback, radiative heating and cooling mechanism are under investigation. Also they applied the individual time step method to the GOTPM to enhance the overall speedups especially for the high resolution simulations. Prof. Kim also translated the GOTPM code into the GPU language (CUDA) and obtained a speed-up factor of about 7 relative to the CPU core.

Prof. Maurice H.P.M. van Putten started a new KIAS research program on gravitational-wave physics and astronomy in light of the upcoming advanced detectors of gravitational radiation. He is the group leader on the Korean side in a Japanese-Korean collaboration on data-analysis for the Large Cryogenic Gravitational-wave Telescope (LCGT). The objectives of the LCGT are fostering international collaboration in the Asia Pacific region on gravitational-wave research and opening a new window of observations on some of the most enigmatic transient sources in the Universe, including core-collapse supernovae and gamma-ray bursts. Dr. Van Putten's model for long duration gravitational-wave bursts for the putative inner engines to some of these events is currently being implemented by LIGO for their injections and searches.

Prof. Yong-Seon Song presented new measurements of the coherent motion of galaxies based on observations of the large-scale redshift-space distortions seen in the two-dimensional two-point correlation function of Luminous Red Galaxies in Data Release Seven of the Sloan Digital Sky Survey. Dr. Song proposed new statistical method to coherently combine Baryon Acoustic Oscillation statistics (BAO) and peculiar velocity measurements exploiting decomposed density-density and velocity-velocity spectra in real space from the observed redshift distortions in redshift space. Dr. Song explored the complementarity of weak lensing and galaxy peculiar velocity measurements to better constrain modifications to General Relativity. Dr. Song, using the latest physical modeling and constrained by the most recent data, develops a phenomenological parameterized model of the contributions to intensity and polarization maps at millimeter wavelengths from external galaxies and Sunyaev-Zeldovich effects.

Dr. Graziano Rossi has combined the physics of the ellipsoidal collapse model with the excursion set theory to study the shapes of dark matter halos. In particular, he has developed an analytic approximation to the nonlinear evolution, introduced a planar representation of halo axis ratios, and provided simple physical explanations for some empirical fitting formulae obtained from numerical studies. Dr. Graziano Rossi, Dr. Prava Chingangbam and Prof. Park have extended the theoretical formalism of the excursion sets statistics to models with local primordial non-Gaussianity. They have confirmed their analytic predictions using simulated CMB full-sky non-Gaussian maps. Dr. Graziano Rossi is currently continuing his work with Prof. Park on LSS topology. The main goal is to constrain cosmological parameters and the equation of state of dark energy with the next generation of galaxy surveys, and in particular with BOSS.

Dr. Jaswant Kumar is working on the Semi-Analytic modelling of the formation and evolution of galaxies in the Universe. He is also inspecting the effects of galaxy-galaxy interactions on the properties of galaxies observed by the Sloan Digital Sky Survey.

Dr. Jeong-Sun Hwang has joined KIAS astrophysics group in September 2010. She has worked on galaxy evolution, in particular, dynamical evolution involved with galaxy-galaxy and galaxy-intergalactic medium (IGM) interactions using smoothed particle hydrodynamics (SPH) simulations. Dr. Hwang and Prof. Park have started a numerical study of interacting galaxies mainly using GADGET-2, an N-body/SPH simulation code. The study aims at investigating the effects of galaxy interactions, including distant flyby encounters, on their properties and overall galaxy evolution.

Dr. Seong-Kook Lee investigated the star-formation histories of high-redshift (3 < z < 6) star-forming galaxies using semi-analytic models of galaxy formation and the principal component analysis, and also analysed the effects of (false) assumption about the star-formation histories on the results of spectral energy distribution (SED) fitting analysis, showing that there can be significant systematic biases in the derived stellar population properties through which. Dr. Lee and Prof. Park are developing a code fitting galaxy spectra to model spectra in order to derive their physical properties.

1) Han, D.-H., Park, C., Choi, Y.-Y., Park, M.-G., The Properties of Type Ia Supernova Host Galaxies from the Sloan Digital Sky Survey, 2010, ApJ, 724, 502

2) Hwang, H. S.; Elbaz, D.; Lee, J. C.; Jeong, W.-S.; Park, C.; Lee, M. G.; Lee, H. M.' Environmental dependence of local luminous infrared galaxies, 2010 (11월), A&A, 522, 33

3) Choi, Yun-Young; Park, Changbom; Kim, Juhan; Gott, J. Richard; Weinberg, David H.; Vogeley, Michael S.; Kim, Sungsoo S.; for the SDSS Collaboration Galaxy Clustering Topology in the Sloan Digital Sky Survey Main Galaxy Sample: A Test for Galaxy Formation Models 2010 (9월), ApJS, 190, 181

4) Hwang, Ho Seong; Park, Changbom, Orbital Dependence of Galaxy Properties in Satellite Systems of Galaxies 2010 (9월), ApJ, 720, 522

5) Wang, Yougang; Park, Changbom; Hwang, Ho Seong; Chen, Xuelei, Distribution of Satellite Galaxies in High-redshift Groups, 2010, ApJ, 718, 762-767 (08/2010)

6) Park, Changbom; Kim, Young-Rae, Large-scale Structure of the Universe as a Cosmic Standard Ruler, 2010, ApJ, 715, L185-L188 (06/2010)

7) Hernández-Toledo, H. M.; Vázquez-Mata, J. A.; Martínez-Vázquez, L. A.; Choi, Yun-Young; Park, Changbom, The UNAM-KIAS Catalog of Isolated Galaxies, 2010, AJ, 139, 2525 (06/2010)

8) Park, Hyunbae; Kim, Juhan; Park, Changbom, Gravitational Potential Environment of Galaxies. I. Simulation, 2010, ApJ, 714, 207 (05/2010)

9) Lee, Joon Hyeop; Lee, Myung Gyoon; Park, Changbom; Choi, Yun-Young, The nature of the Sloan Digital Sky Survey galaxies in various classes based on morphology, colour and spectral features - III. Environments, 2010, MNRAS, 403, 1930 (04/2010)

10) Cervantes-Sodi, B.; Hernandez, X.; Park, Changbom, Clues on the origin of galactic angular momentum from looking at galaxy pairs, 2010, MNRAS, 402, 1807 (03/2010)

11) van Putten, M.H.P.M., Kanda, N., Tagoshi, H., Tatsumi, D., Masa-Katsu, F., & Della Valle, M., 2011, Prospects for true calorimetry on Kerr black holes in core-collapse supernovae and mergers, PRD, 83, 044046

12) van Putten, M.H.P.M., & Levinson, A., 2011, Relativistic Astrophysics of the Transient Universe (Cambridge University Press), accepted

13) G. Rossi, P. Chingangbam and C. Park, Statistics of the excursion sets in models with local primordial non-Gaussianity, MNRAS, 411, 1880-1896, (2011)

14) G. Rossi, P. Chingangbam and C. Park,Excursion set statistics with primordial non-Gaussianity, JKPS, Vol. 57, No. 3, pp. 563-566

15) Lee, S.-K., Ferguson, H. C., Somerville, R. S., Wiklind, T., & Giavalisco, M., The Estimation of Star Formation Rates and Stellar Population Ages of High-redshift Galaxies from Broadband Photometry, 2010, ApJ, 725, 1644 (Dec. 2010)

16) Dahlen, T., Mobasher, B., Dickinson, M., Ferguson, H. C., Giavalisco, M., Grogin, N., Guo, Y., Koekemoer, A., Lee, K.-S., Lee, S.-K., et al., A Detailed Study of Photometric Redshifts for GOODS-South Galaxies, 2010, ApJ, 724, 425 (Nov. 2010)

Proceedings

1) Ann, H. B., Park, C., & Choi, Y. Y. Isolated Galaxies and Isolated Satellite Systems, 2010, ASPC, 421, 15

2) Cervantes-Sodi, Bernardo; Hernandez, X.; Park, Changbom, Origin and Evolution of Galactic Spin from Looking at Galaxy Pairs 2010, AIPC, 1240, 407C

3) Vázquez-Mata, J. A.; Hernández-Toledo, H. M.; Park, Changbom; Choi, Yun-Young, A New Catalog of Isolated Galaxies 2010, IAUS, 267, 464

4) G. Rossi, Desperately seeking non-Gaussianity in the Cosmic Microwave Background, Moriond Proceedings 2010, "Cosmology"

5) G. Rossi, Primordial non-Gaussianity and excursion sets, COSMO/CosPA 2010, The University of Tokyo, Tokyo, Japan, October 1, 2010

Presentations at Meetings

1) Changbom Park, Environmental Effects on Galaxy Formation, ARCSEC Workshop 2011, Yongpyung, Jan. 18-20, 2011

2) Changbom Park, Computation in Astronomy - Challenges and Opportunities, 천문학회 장기발전계획 수립을 위한 워크숍, 천문학회, 서울대학교, Jan. 17, 2011

3) Changbom Park, Progresses of the Sloan Digital Sky Survey, 한국물리학회, Oct. 20-22, 2010

4) 이광호, 우종학, 이명균, 박창범, 최윤영, 황호성, 이종환, 손주비, The AGN-Bar Connection, 2010 한국천문학회 가을 학술대회, 변산 대명리조트, Oct. 7-8, 2010

5) Bernardo Cervantes-Sodi, Changbom Park, & X. Hernandes, Quantifying galactic morphological transformations in the cluster environment, 2010 한국천문학회 가을 학술대회, 변산 대명리조트, Oct. 7-8, 2010

6) Pravabati Chingangbam, & Changbom Park, Constraining non-Gaussianity with Minkowski Functionals, 2010 한국천문학회 가을 학술대회, 변산 대명리조트, Oct. 7-8, 2010

7) 안경진, 홍성욱, 박창범, 김주한, Ilian T. Iliev, & G. Mellema, 2D genus topology of 21-cm differential brightness temperature during cosmic reionization, 2010 한국천문학회 가을 학술대회, 변산 대명리조트, Oct. 7-8, 2010

8) 박창범, Rien van de Weygaert, W. Hellwing, & 김주한, Simulation of the SDSS Survey Region of the Universe, 2010 한국천문학회 가을 학술대회, 변산 대명리조트, Oct. 7-8, 2010

9) Changbom Park, Galaxy Clustering Topology: A Galaxy Formation Model Test, Workshop on Redshift Survey & Large-Scale Structure, National Astronomical Observatory of China, Jun. 24, 2010

10) Changbom Park, Topology of Large Scale Structure (three invited lectures), Summer School on Redshift Survey & Large-Scale Structure, NAOC, Beijing, China, Jun. 13-23, 2010

11) Changbom Park, Large-Scale Structure Topology as a Cosmic Ruler, CITA@25 Bond@60 Workshop, Canadian Institute for Theoretical Astrophysics, Univ. of Toronto, Toronto, Canada, May 13-16, 2010

12) 이광호, 박창범, 이명균, 최윤영, Dependence of Barredness of Late-Type Galaxies on Galaxy Properties and Environment, 2010 한국천문학회 봄 학술대회, 경희대학교, Apr. 8-9, 2010

13) 최윤영, 박창범, 김주한, Weinberg, D. H., 김성수, Gott, J. R., Vogeley, M. S., Topology of Galaxy Clustering in the Sloan Digital Sky Survey Main Galaxy Sample: a Test for Galaxy Formation Models, 2010 한국천문학회 봄 학술대회, 경희대학교, Apr. 8-9, 2010

14) Juhan Kim, How to Build a Parallel Computer in a Lab, The 1st KIAS CAC Winter School on Parallel Computing, KIAS, Seoul, Feb. 22-23, 2011

15) Juhan Kim & Changbom Park, Cosmological Simulation Powered by CUDA, NIMS, Daejeon, 2010

16) Juhan Kim, KIAS GPU 컴퓨팅 시스템 소개, Korea Supercomputing Conference 2010, Seoul, Dec. 6-7, 2010

17) Yong-Seon Song, New cosmological probe of dark energy, Nordita The return of de Sitter workshop, 2011-03

18) Yong-Seon Song, The case of wide and deep survey. 서울대학교 한국 천문학회 중장기 발전계획 워크샵, 2011-01

19) Yong-Seon Song, Cosmological implication of coherent motion measurements / Brisbane-Queensland University Cosmic Co-Motion Workshop, 2011-10

20) Yong-Seon Song, Decomposition of coherent motions from redshift survey / Brisbane-Queensland University Cosmic Co-Motion Workshop, 2011-10

21) Yong-Seon Song, Dark sides of universe, Daejon QGC 2010

22) Yong-Seon Song, Nature of dark energy, APCTP Dark sides of universe, 2010-08

23) Jeong-Sun Hwang, Models of Arp 285: The Formation of "Beads on a String" in the Accretion Tail, The 4th KIAS Workshop on Cosmology and Structure Formation, KIAS, Seoul, Nov. 3-7, 2010

24) Lee, S.-K., SED-fitting Analysis of High-redshift Star-forming Galaxies: Effects of Assumed Star-formation Histories, The 4th KIAS workshop on Cosmology and Structure Formation, KIAS, Seoul, Nov. 3-7, 2010

25) Graziano Rossi, "CMB non-Gaussianities: statistical methods and their applications", Allahabad, India - December 16, 2010 - Meeting on ``Primordial features and non-Gaussianities at the Harish-Chandra Research Institute (HRI)

26) Graziano Rossi, "Non-Gaussianities in the CMB", Seoul, South Korea - November 4, 2010 - The ``4th KIAS Workshop on Cosmology and Structure Formation at KIAS

27) Graziano Rossi, "Testing the expansion of the Universe with the GMT", Seoul, South Korea - October 5, 2010 - The ``GMT2010: Opening New Frontiers with the Giant Magellan Telescope at Seoul National University

28) Graziano Rossi, "Photometric redshifts, convolution and deconvolution techniques", Beijing, China - June 23, 2010 - Workshop on ``Redshift Survey and Large Scale Structure at the National Astronomical Observatory

29) Graziano Rossi, "Non-Gaussianity of the CMB and excursion sets", Toronto, Canada - May 14, 2010 - CITA@25 and BOND@60 - Conference for the 25th Anniversary of the Canadian Institute for Theoretical Astrophysics (CITA)

30) Graziano Rossi, "CMB excursion sets and primordial non-Gaussianity", La Thuile, Aosta Valley, Italy - March 16, 2010 - XLVth Rencontres de Moriond, ``Cosmology: the new challenges, Hotel Planibel - Contributed talk in the ``CMB/Polarization section

Colloquiums, Seminars and Lectures

1) Changbom Park, 천문기록에 담긴 한국사의 수수께끼, 참여불교 리더스포럼, 만해NGO교육센터, Dec. 7, 2010

2) Changbom Park, 21세기 과학이 본 우주의 실체, 경기과학고, Dec. 6, 2010

3) Changbom Park, 21세기 과학이 본 우주의 실체, 인천시민의 과학 나들이, 인천 미추홀 도서관, Nov. 13, 2010

4) Changbom Park, 하늘의 과학, 경기도 박물관, Oct. 13, 2010

5) Changbom Park, Effects of Large-Scale Background and Galaxy-Galaxy Interactions on Galaxy Properties, Kapteyn Institute Colloquium, Sept. 20, 2010

6) Changbom Park, Astronomical Tradition in Korea and Modern Applications, Kapteyn Institute Seminar, Sept. 2, 2010

7) Juhan Kim, Tutorial on the GPU Cluster, KIAS, Seoul, Jan. 31, 2011

8) van Putten, M.H.P.M., February 7 2011, ``Eyes on e," KIAS Lecture to Science High School students, KIAS, Seoul

9) Yong-Seon Song, The future of large scale structure formation, 서울대학교 콜로퀴엄, 2011-03

10) Yong-Seon Song, Modeling Extragalactic Foregrounds and Secondaries for Unbiased Estimation of Cosmological Parameters From Primary CMB Anisotropy, 교토대학교 세미나, 2011-03

11) Yong-Seon Song, Lectures of dark energy II - GR test, Stockholm Winter school on cosmic acceleration, 2011-03

12) Yong-Seon Song, Lectures of dark energy I - Classification of dark energy models / Stockholm Winter on cosmic acceleration, 2011-03

13) Yong-Seon Song, Dark energy special lectures / KIAS KIAS conference, 2010-11

14) Yong-Seon Song, Cosmological implication of measuring coherent motions / KASI KASI Colloquium, 2010-11

15) Yong-Seon Song, 현대 우주론의 진화와 미래 / 경북대학교 경북대학교 콜로키엄, 2010-09

16) Graziano Rossi, "Cosmological challenges in the new decade: non-Gaussianity, LSS topology, and photometric redshift surveys", Milano, Italy - January 28, 2011 - INAF, Osservatorio Astronomico di Merate

17) Graziano Rossi, "Statistical techniques for detecting primordial non-Gaussianity", Seoul, South Korea - August 19, 2010 - APCTP Mini Workshop on ``Recent progresses in Dark-Universe and Astrophysics

18) Graziano Rossi, "Non-Gaussianity: a pedagogical review", Pohang, South Korea - May 7, 2010 - APCTP-IEU ``Focus Program on Cosmology and Fundamental Physics - Postech Headquarter

19) Jeong-Sun Hwang, Models of Galaxy Interactions in Stephan's Quintet, KISTI, Daejeon, Oct. 29, 2010

20) Lee, S.-K., Physical Properties and Star-formation Histories of High-redshift Star-forming Galaxies, SNU Colloquium, Seoul National University, Seoul, Sep. 30, 2010

Meeting Organization

1) Meeting: Summer School on Redshift Survey & Large-Scale Structure

Host: National Astronomical Observatory of China

Place: NAOC, Beijing, China

Date: Jun. 13-23, 2010

Organizer: Changbom Park (SOC member)

http://cosmology.bao.ac.cn/~summer2010/index.html

2) Meeting: The 4th KIAS Workshop on COSMOLOGY AND STRUCTURE FORMATION

Host: KIAS

Place: KIAS, Seoul, Korea

Date: Nov. 4-7, 2010

Organizer. Changbom Park (Host)

http://conf.kias.re.kr/cosmology10/

3) Meeting: Workshop for Next Generation Supercomputing - GPU Applications for Astrophysical Problems

Host: KIAS, NIMS

Place: NIMS

Date: Dec. 8-10, 2010

Organizer: Changbom Park (SOC member)

http://csm.nims.re.kr/gputoast2010/GPUToAst2010/GPUToAst2010.html

4) Meeting: EAYAM (East Asian Young Astronomers Meeting) 2011

Host: KYAM

Place: Dae Myeong, Jeju, Korea

Date: Feb. 13-18, 2011

Organizer: Changbom Park (SOC Chair)

http:// ikha.or.kr/eayam2011

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

14박창범, 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

The astrophysics and cosmology group of Korea Institute for Advanced Study consists of Prof. Changbom Park, and six research fellows. Prof. Park has 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).

Individual members of the astrophysics and cosmology group have been active in his/her research in 2008. Dr. Yun-Young Choi and Prof. Park have studied the effects of environments, namely, the nearest neighbor galaxy and large-scale density, on the galaxy properties using the SDSS data. They have also studied the effects of the host galaxy and large-scale background density on the satellite galaxies in isolated galactic satellite systems. They measured the topology of the large-scale distribution of the luminous red galaxies observed by the SDSS. An astonishing agreement between the observed genus and the genus from a CDM model simulation was found. Dr. Choi moved to ARCSEC in Sejong University.

Dr. Juhan Kim and Prof. Park have run the Horizon Run N-body Simulation, the biggest cosmological N-body simulation till date, on a supercomputer at Korea Institute for Science and Technology Information. The evolution of matter fluctuation is shown from the present epoch all the way out to the horizon (the Big bang surface) for the first time. Massive dark matter halos are identified for a comparison with observations of the forthcoming BOSS of the SDSS-III project. The simulation is used to accurately measure the non-linear systematic effects such as gravitational evolution, redshift space distortion, past light cone space gradient, and galaxy biasing, and to calibrate the baryon oscillation scale and the genus topology. Dr. Kim moved to CITA in University of Toronto in Aug. 2008.

Dr. Prava Chingangbam studied models of inflation which give rise to features in the primordial power spectrum. It was found that a particular model, motivated by MSSM in particle physics, with potential having an inflection point provides a much better fit to CMB data compared to the usual power-law spectrum, particularly for the low multipoles. She also worked on possible scenarios where the amplitude of curvature perturbation on super-horizon scales can be modified during reheating. Further, she has calculated the trispectrum in axion-type curvaton model and found that it can be relevant for non-Gaussianity in the CMB. Dr. Chingangbam and Prof. Park developed codes for simulation of non-Gaussian CMB maps and are computing Minkowski Functionals from these maps. She gave a series of lectures on cosmological perturbation theory and a seminar at National Taiwan University.

Dr. Ho Seong Hwang and Prof. Park studied the effects of galaxy-galaxy and galaxy-cluster interactions on galaxy properties, and found that the galaxy-galaxy interaction has been one of the main driving causes for galaxy evolution in the cluster environment and also at high redshifts. The SDSS galaxies in the massive Abell clusters, and high redshift (z<1) galaxies in the Hubble Space Telescope archival data and ground-based spectroscopic data, were used. They investigated the kinematics of satellite galaxies using the SDSS data.

Dr. Young-Rae Kim and Prof. Park are continuing their research on topology and large scale structure as a probe of cosmology. They have formulated the estimated genus value at a given cosmology by using a volume factor with respect to a reference cosmology and genus values at scaled smoothing length for the new cosmology and the reference smoothing length. They estimated how well their method can constrain cosmology once SDSS-III is completed. They are now using the Horizon Run to measure the non-linear corrections and calibrate their analysis.

Dr. Pascale Hibon has joined KIAS astrophysics group in June 2008. She has been searching for high redshift (z=7.7) Lyman-alpha Emitters from Narrow-Band Imaging Survey. She visited NAOJ in Sept. 2008, where she created a new collaboration, resulting in two new observational projects. Dr. Pascale Hibon and Prof. Park have also been investigating the interactions of galaxy-galaxy pairs using the GOODS data.

Dr. Graziano Rossi, who joined KIAS astrophysics group in Sept. 2008, studied the statistics of the cosmic microwave background fluctuations such as the higher order correlations and peak statistics using the five-year WMAP data. He also worked on deconvolution techniques for galaxy scaling relations and statistical estimation problems.

Papers

1. Adelman-McCarthy, J. K. et al., The Sixth Data Release of the Sloan Digital Sky Survey, 2008, ApJS, 175, 297

2. Hwang, Ho Seong, & Lee, M. G., Galaxy Orbits for Galaxy Clusters in Sloan Digital Sky Survey and 2dF Galaxy Redshift Survey, 2008, ApJ, 676, 218

3. Kim, Juhan, Park, Changbom, & Choi, Y.-Y., A Subhalo-Galaxy Correspondence Model of Galaxy Biasing, 2008, ApJ, 683, 123

4. Cervantes-Sodi, B., Hernandez, X., Park, Changbom, & Kim, Juhan, Environment and mass dependencies of galactic λ spin parameter: cosmological simulations and observed galaxies compared, 2008, MNRAS, 388, 863

5. Ann, H. B., Park, Changbom, & Choi, Yun-Young, Galactic satellite systems: radial distribution and environment dependence of galaxy morphology, 2008, MNRAS, 389, 86

6. Lee, J. H., Lee, M. G., Park, Changbom, & Choi, Y.-Y., The nature of the Sloan Digital Sky Survey galaxies in various classes based on morphology, colour and spectral features - I. Optical properties, 2008, MNRAS, 389, 1791

7. Park, Changbom, & Choi, Yun-Young, Combined Effects of Galaxy Interactions and Large-Scale Environment on Galaxy Properties, 2009, ApJ, 691, 1828

8. Cho, J., & Park, Changbom, Internal Extinction in the SDSS Late-Type Galaxies, 2009, ApJ, 693, 1045

9. Wang, Y., Park, Changbom, Yang, X., Choi, Yun-Young, & Chen, X., Alignment between the host and the nearest neighbor Groups, 2008, ApJ, submitted (arXiv0810.3359)

10. Kim, Juhan, 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, 2008, ApJ, submitted (arXiv0812.1392)

11. Gott, J. R., Choi, Yun-Young, Park, Changbom, & Kim, Juhan, 3D Genus Topology of Luminous Red Galaxies, 2008, ApJ, submitted (arXiv0812.1406)

12. Jain, R. K., Chingangbam, Pravabati, Gong, J. O., Sriramkumar, L. & Souradeep, T.,  Punctuated inflation and the low CMB multipoles, 2008, JCAP, in press, astro-ph/0809.3915

13. Jain, R. K., Chingangbam, Pravabati & Sriramkumar, L., Reheating in tachyonic inflationary models: Effects on the large scale curvature perturbations, 2008, JCAP, submitted, astro-ph/0902.1067

14. Chingangbam, Pravabati and Huang, Q.G., The curvature perturbation in the axion-type curvaton model, 2009, JCAP, accepted, astro-ph/0902.2619

15. Ko, J., Im, M., Lee, H. M., Lee, M. G., Hopwood, R., Serjeant, S., Smail, I., Hwang, H. S., Hwang, N., Shim, H., Kim, S. J., Lee, J. C., Lim, S., Seo, H., Goto, T., Hanami, H., Matsuhara, M., Takagi, T., Wada, T., The Mid-infrared View of Red Sequence Galaxies in Abell 2218 with AKARI, 2009, ApJL, accepted

16. Park, Changbom & Hwang, Ho Seong, Interactions of Galaxies in the Galaxy Cluster Environment, 2008, ApJ, submitted (arXiv0812.2088)

17. Hwang, Ho Seong, & Lee, M. G., Galaxy Activity in Merging Binary Galaxy Clusters, 2008, MNRAS, submitted

18. Choi, Y.-Y., Woo, J.-H., & Park, Changbom, Environment Dependence of AGN Activity. I: The Effects of Host Galaxy, 2008, ApJ, submitted

19. Lee, J. H., Lee, M. G., Park, Changbom, Choi, Y.-Y., The Nature of the SDSS Galaxies in various classes based on morphology, colour and spectral features - II. Multi-wavelength properties, 2008, MNRAS, submitted

20. Hernandez-Toledo, H. M., Martinez-Vazquez, J. A., Choi, Y.-Y., & Park, Changbom, The UNAM-KIAS Catalog of Isolated Galaxies, 2008, ApJ, submitted

21. Hwang, Ho Seong, & Park, Changbom, Evidence for Morphology and Luminosity Transformation of Galaxies at High Redshifts, 2008, ApJ, submitted

Presentations at Meetings

1. Park, C., The New Era of Large-Scale Survey of the Universe, Korea Astronomical Society Meeting, KIAS, Seoul, Apr. 11, 2008 (opening plenary talk)

2. Hwang, H. S. (speaker), Lee, J. C., Lee, M. G., Serjeant, S., Nakagawa, T., Jeong, W.-S., Pearson, C., Progress Report of AKARI NIR Spectroscopy of Ultraluminous Infrared Galaxies at Intermediate Redshift, Korea Astronomical Society Meeting, KIAS, Seoul, Apr. 11, 2008

3. Kim, Juhan (speaker), & Park, Changbom, Cosmological N-body Simulation Powered by the Graphics Processing Unit -- I. A Progress Report, Korea Astronomical Society Meeting, KIAS, Seoul, Apr. 11, 2008

4. Park, C., Dark Energy Constraints from the Large Scale Structure of the Universe, Korean Physics Society Meeting - International session, Daejeon, Apr. 17, 2008 (invited)

5. Park, C., Effects of Interactions and Large-Scale Environment of Galaxy Properties, East Asian Young Astronomers Meeting 2008, Jiayugwan, China, Jul. 30, 2008 (invited)

6. Park, Changbom, Galaxy-Galaxy Interactions in the General Environment and Clusters of Galaxies, An International Symposium. The Sloan Digital Sky Survey: From Astroids to Cosmology, The Kavli Institute for Cosmological Physics, Chicago, USA, Aug. 15-18, 2008

7. Hwang, H. S. (speaker), Park, C., Effects of Galaxy-Galaxy Interaction on Morphology and Luminosity of High redshift Galaxies, Korea Astronomical Society Meeting, Gyungju, Oct. 10, 2008

8. Hwang, H. S., & Park, C., Kinematics of Satellite Systems of Galaxies: Prograde and Retrograde Motion, Korea Astronomical Society Meeting, Gyungju, Oct. 10, 2008 (poster)

9. Choi, Y.-Y. (speaker), Park, C., Woo, J.-H., Environmental Dependence of AGN Activity. I: The Effects of Host Galaxy, Korea Astronomical Society Meeting, Gyungju, Oct. 10, 2008

10. Ann, H. (speaker), Park, C., Choi, Y.-Y., Morphology Conformity in Galactic Satellite Systems, Korea Astronomical Society Meeting, Gyungju, Oct. 10, 2008

11. Park, C., How galaxy interaction and large-scale environment jointly determine galaxy properties?, Korea Astronomical Society Meeting, Gyungju, Oct. 10, 2008

12. Kim, Y.-R. (speaker), & Park, C., Cosmological Parameter Estimation from Large Scale Structure Topology, Korea Astronomical Society Meeting, Gyungju, Oct. 10, 2008

13. Park, C., Spatial and Temporal Environmental Effects on Galaxy Properties, KIAS Workshop on Cosmology and Structure Formation, KIAS, Oct. 27-28, 2008

14. Park, C., Cosmology from Topology of Large Scale Structure of the Universe, RESCEU Symposium on Astroparticle Physics and Cosmology, The University of Tokyo, Tokyo, Japan, Nov. 11-14, 2008 (invited)

15. Rossi, G., Peak Statistics in the WMAP Sky: Non-Gaussianity?, RESCEU Symposium on Astroparticle Physics and Cosmology, The University of Tokyo, Tokyo, Japan, Nov. 11-14, 2008

16. Rossi, G., Hunting for non-Gaussianity: Clustering Statistics in the WMAP5 Sky, 24th Texas Symposium on Relativistic Astrophysics, Vancouver, Canada, Dec. 8-12, 2008

17. Hwang, H. S. (speaker), & Park, C., Environment Dependent Evolution of High-redshift Galaxies, American Astronomical Society Meeting, Long Beach, USA, Jan, 5, 2009

18. Park, C., Galaxy Properties in Dark Matter Halo Evironments, The 8th Sino-German workshop on the tumultuous lives of gaalxies, supermassive blackholes and their dark halos, Kunming, China, Feb. 23-28, 2009 (invited)

19. Rossi, G., Primordial non-Gaussianity in the CMB: Theoretical and Observational Challenges, Workshop on Connecting Fundamental Physics with Observations, Kavli Institute for Theoretical Physics (KITCP), Beijing, China, Feb. 16 - Apr. 30 (invited)

The astrophysics and cosmology group of Korea Institute for Advanced Study consists of Prof. Changbom Park, and five research fellows. Prof. Park, as the director of the Korean Scientist Group (KSG), has continued leading the international consortium of the Sloan Digital Sky Survey (SDSS). The SDSS is an ambitious international collaboration aiming to survey a hugh volume of the universe by taking a million galaxy spectra, and the data from the survey is expected to contribute to the development of cosmology profoundly. Now the KSG consists of 10 professors and 27 postdocs and graduate students in eight institutes in Korea. In September, 2006, KIAS and KSG have hosted the 2006 SDSS Collaboration Meeting at Seoul National University. The meeting, participated by 120 people, was open to all Korean scientists, and provided a momentum for stimulating great interests in galactic and extra-galactic astronomy in Korea. The astrophysics and cosmology group has organized the biennial international workshop "The 2nd KIAS International Workshop on Cosmology and Structure Formation". There were 12 invited talks on inflation, cosmic microwave background (CMB), large-scale structure and galaxy formation. Prof. Park and Dr. Juhan Kim have formed a group called 'Computational Astrophysics Group' to share knowledges on computational hydrodynamics, MHD, N-body simulation, and parallel computation among astrophysicists in Korea. The first meeting was held in June, 2006, and five meetings have been held at KIAS.

Individual members of the astrophysics and cosmology group have also been active in his/her research in 2006. Dr. Chan-Gyung Park together with Prof. Park have produced a foreground-cleaned three-year (CMB) temperature fluctuation map from the WMAP three-year data. They examined the statistical properties of the large scale modes, and found that most known peculiarities of large scale modes were only marginally significant. The genus statistic was measured from the CMB map to test for the Gaussianity of the primordial fluctuations, and it was found that the Galactic north-south asymmetry was also marginally significant. Using the SDSS galaxy sample, Dr. Chan-Gyung Park and Prof. Park have also been measuring the velocity dispersion functions of the early and late type galaxies.

Dr. Yun-Young Choi and Prof. Park have studied the relations among various physical properties of the SDSS galaxies. It was found that, at fixed morphology and luminosity, early types show very small dispersions in color, color gradient, concentration, size, and velocity dispersion. Many parameters manifest different behaviors across the absolute magnitude of about M*. They have also used a new local density estimator to explore the relation between the environment and galaxy properties. It was found that variations of galaxy properties with environment were almost entirely due to the dependence of morphology and luminosity on environment. When morphology and luminosity are fixed, other physical properties are nearly independent of local density without any break or feature. Weak residual dependences on environment include that of the color of late-types and of the luminosity-velocity dispersion relation of early types. Motivated by the study of effects of local density and the nearest companion on galaxy morphology, they have proposed a mechanism that the morphology of galaxies in galaxy systems is transformed by the tidal force.

Dr. Juhan Kim has improved the cosmological N-body simulation code for better parallel performance and memory-cost. Dr. Kim, Prof. Park, and Dr. Choi are using new simulation results to investigate the environmental effects on the luminosity, spin, and shape of mock galaxies (dark halos) in the one-to-one monotonic correspondence model and compared the results with those found from the SDSS sample.

Dr. Pravabati Chingangbam has studied the effect of a fast rolling period in between two slow roll inflationary periods on the evolution of curvature perturbations generated by a Dirac-Born-Infeld scalar field, and showed that the amplitude of perturbations get amplified at super-Hubble scales. The entropy perturbations are shown to act as the source for this amplification. Dr. Chingangbam has also worked on the dynamics of DBI scalar field, minimally coupled to gravity, with a potential which is negative for a range of field values. The fate of the universe at late times is found to depend on the negative depth of the potential.

Recently, Dr. Jaiseung Kim joined the group from Brown University. Dr. Kim is working on a new method to reduce the Galactic foreground emission in the CMB maps by requiring randomness of spherical harmonics modes of the CMB.

Papers

1. Park, Chan-Gyung, and Park, Changbom, 2006, Power Spectrum of Cosmic Momentum Field Measured from the SFI Galaxy Sample, Astrophysical J., 637, 1-11

2. Juhan, Kim, and Changbom Park, 2006, A New Halo Finding Method for N-Body Simulations, Astrophysical J., 639, 600-616

3. Hernandez, X., Park, Changbom, Cervantes-Sodi, B., & Choi Y.-Y. 2006, Empirical Distribution of Galactic Spin Parameters from the SDSS, MNRAS, 375, 163-170

4. Tegmark, M. et al. 2006, Cosmological Constraints from the SDSS Luminous Red Galaxies, Phys. Rev. D74 (2006) 123507

5. Park, Changbom, Choi, Y.-Y., Vogeley, M. S., Blanton, M. R., & Gott, J. R. 2007, Environment Dependence of Properties of Galaxies in the Sloan Digital Sky Survey, ApJ, 657, in press

6. Choi, Y.-Y., Park, Changbom, Vogeley, M. S., & Gott, J. R. 2007, Internal and Collective Properties of Galaxies in the Sloan Digital Sky Survey, ApJ, 657, in press

7. Park, C.-G., Park, Changbom, & Gott, J. R. 2007, Cleaned Three-Year WMAP CMB Map: Magnitude of the Quadrupole and Alignment of Large Scale Modes, ApJ, accepted

8. Gott, J. R., Hambrick, D. C., Vogeley, M. S., Kim, J., Park, Changbom, Choi, Y.-Y., Cen, R., Ostriker, J. P., & Nagamine, K. 2007, Topology of Structure in the Sloan Digital Sky Survey: Model Testing, ApJ, submitted.

9. Gott, J. R., Colley, W. N., Park, C.-G., & Park, Changbom, 2007, Genus Topology of the Cosmic Microwave Background from the WMAP 3-Year Data, MNRAS, submitted.

Invited talks

1. Park, Changbom, "Science Cases with the WFT of the SPM-Twin: Hubble-Depth Survey Project & Etc.", 10th Guillermo Haro workshop, Mexico, (2006. 7. 6).

2. Park, Changbom, & Kim, Juhan, "Cosmological N-Body Simulation - Topology of Large Scale Structure", Conference on Computational Physics 2006, Gyung-Ju, Korea, (2006. 8. 29).

3. Park, Changbom, "Large Scale Structure and Galaxy Properties", SDSS Collaboration Meeting, Seoul National Univ., (2006. 9. 22)

4. Park, Changbom, "The Hubble Depth Survey Project", Cosmology with Wide-field Photometric and Spectroscopic Galaxy Surveys, Tokyo Univ. (2006. 11. 9)

Contributed talks

1. Park, Changbom, & Choi, Yun-Young, "Environment-Dependence of Galaxy Properties", SDSS Collaboration Meeting, Santa Fe, (2006. 3. 25).

2. Park, Changbom, & Choi, Yun-Young, "Dependence of Galaxy Properties on Environment: Internal Properties", KAS Meeting 2006 Spring, Seoul National Univ. (2006. 4. 13).

3. Choi, Yun-Young, "Topology Analysis of the SDSS: Morphology, Color, and Velocity Dispersion Dependence", KAS Meeting 2006 Spring, Seoul National Univ. (2006. 4. 13)

4. Park, Changbom, "Void Identification in Observation and Void Definition in Simulation", Cosmic Void Workshop, Aspen, (2006. 5. 31).

5. Park, Changbom, & Yun-Young, Choi, "Observational and Theoretical Studies of Topology of Large Scale Structure", Cosmic Void Workshop, Aspen, (2006. 6. 2).

6. Park, Changbom, Choi, Yun-Young, Vogeley, M. S., Gott, J. R., "Environment and Galaxy Properties", Cosmic Void Workshop, Aspen, (2006. 6. 5).

7. Kim, Juhan, Park, Changbom, & Choi, Yun-Young, "A Simple Method to Build Mock Galaxies", Cosmic Void Workshop, Aspen, (2006. 6. 6).

8. Kim, Juhan, Gott, J.R., Hambrick, C., Vogeley, M., Park, C., Choi, Y.-Y., Cen, R., Ostriker, J., & Nagamine, K. "Topology of Structure in SDSS: Model test", SDSS Collaboration Meeting, Seoul National Uuiv., (2006. 9. 24).

9. Choi, Yun-Young, "Environmental Dependence of Properties of Galaxies in the Sloan Digital Sky Survey", KAS Meeting 2006 Fall (2006. 10. 20)

10. Park, Chan-Gyung, "Large-Scale Modes of Cleaned Three-Year WMAP CMB Map", CosPA2006, Taiwan (2006. 11. 15)