Systematic study of the stellar initial mass function and its variation

2016 Fiscal Year Annual Research Report

• Project/Area Number: 15K17600
• Research Institution: The University of Tokyo
• Principal Investigator: MORE Surhud 東京大学, カブリ数物連携宇宙研究機構, 特任助教 (00646044)
• Project Period (FY): 2015-04-01 – 2017-03-31
• Keywords: Stellar IMF constraints / HSC weak lensing

Outline of Annual Research Achievements

The main goals of the project was to pursue investigations of the initial mass function using combination of spectroscopic data as well as weak gravitational lensing from the Hyper Suprime Cam survey. The spectroscopic indices as indicated in the previous report have been thought to be unreliable and therefore more focus was given to the weak lensing aspects of this research project. Accordingly I am urrently working on the weak lensing results from the Hyper-Suprime Cam survey. I have developed the weak lensing pipeline to measure the weak lensing signals and to help test for systematics as proposed in the original plan. I have also helped the software team further test a new parameter important for quantifying the blendedness of galaxies (this would be important to measure weak lensing signals at small separation from the foreground lens galaxies).
The back up project to obtain constraints on the initial mass function using data from CFHTLens and CMASS galaxies was published in Jun 2015. This project was a pilot project to test how weak lensing signal from scales from HSC can be used to constrain the stellar masses of CMASS galaxies. The resulting constraints were already sensitive to rule out some measurement of stellar masses based on stellar population synthesis models. This project will now be attempted with the data from HSC.
As reported last year, the investigation of halo assembly bias and the splashback radius of galaxy clusters was one of the unexpected outcomes while exploring this project. I continued investigation on
this topic with separate research grant.

Remarks

All of the papers were posted online to the community peer review
website www.arxiv.org

Research Products

• [Int'l Joint Research] Carnegie Melon University/Princeton University/Jet Propulsion Laboratory Caltech(米国)
  • Country Name: U.S.A.
  • Counterpart Institution: Carnegie Melon University/Princeton University/Jet Propulsion Laboratory Caltech
• [Int'l Joint Research] Max Planck Institute for astrophysics(Germany)
  • Country Name: Germany
  • Counterpart Institution: Max Planck Institute for astrophysics
• [Journal Article] Testing gravity on large scales by combining weak lensing with galaxy clustering using CFHTLenS and BOSS CMASS (2017)
  • Author(s): Alam, S., Miyatake, H., More, S., Ho, S. and Mandelbaum, R.
  • Journal Title: MNRAS Volume: 465 Pages: 4853-4865
  • DOI: 10.1093/mnras/stw3056
  • Peer Reviewed / Int'l Joint Research
• [Journal Article] A new quadruple gravitational lens from the Hyper Suprime-Cam Survey: the puzzle of HSC J115252+004733 (2017)
  • Author(s): More, A., More, S. (8th author in 19 authors) et.al
  • Journal Title: MNRAS Volume: 465 Pages: 2411-2419
  • DOI: 10.1093/mnras/stw2924
  • Peer Reviewed / Int'l Joint Research
• [Journal Article] Interpreting the Strongly Lensed Supernova iPTF16geu: Time Delay Predictions, Microlensing, and Lensing Rates (2017)
  • Author(s): More, A. , Suyu, S.H., Oguri, M., More, S., Lee, C.-H.
  • Journal Title: ApJ Volume: 835 Pages: L25
  • DOI: 10.3847/2041-8213/835/2/L25
  • Peer Reviewed / Int'l Joint Research
• [Journal Article] Detection of the Splashback Radius and Halo Assembly Bias of Massive Galaxy Clusters (2016)
  • Author(s): More, S., Miyatake, H., Takada, M., Diemer, B., Kravtsov, A.V., Dalal, N.K., More, A., Murata, R., Mandelbaum, R.,Rozo, E.,Rykoff, E.S., Oguri, M., and Spergel, D.N.
  • Journal Title: ApJ Volume: 825 Pages: 39
  • DOI: 10.3847/0004-637X/825/1/39
  • Peer Reviewed / Int'l Joint Research
• [Journal Article] The Subaru FMOS galaxy redshift survey (FastSound). IV. New constraint on gravity theory from redshift space distortions at z {\tilde} 1.4 (2016)
  • Author(s): Okumura, T., More, S. (9th author of 25th authors) et. al
  • Journal Title: PASJ Volume: 68 Pages: 38
  • DOI: 10.1093/pasj/psw029
  • Peer Reviewed / Int'l Joint Research
• [Journal Article] Strong bimodality in the host halo mass of central galaxies from galaxy-galaxy lensing (2016)
  • Author(s): Mandelbaum, R. , Wang, W., Zu, Y., White, S., Henriques, B. and More, S.
  • Journal Title: MNRAS Volume: 457 Pages: 3200-3218
  • DOI: 10.1093/mnras/stw188
  • Peer Reviewed / Int'l Joint Research
• [Journal Article] Evolution of Stellar-to-Halo Mass Ratio at z = 0 - 7 Identified by Clustering Analysis with the Hubble Legacy Imaging and Early Subaru/Hyper Suprime-Cam Survey Data (2016)
  • Author(s): Harikane}, Y., Ouchi, M., Ono, Y., More, S., Saito, S., Lin, Y.-T., Coupon, J., Shimasaku, K., Shibuya}, T., Price, P.A., Lin, L., Hsieh, B.-C., Ishigaki, M., Komiyama, Y., Silverman, J., Takata, T., Tamazawa, H. and Toshikawa, J.
  • Journal Title: ApJ Volume: 821 Pages: 123
  • DOI: 10.3847/0004-637X/821/2/123
  • Peer Reviewed / Int'l Joint Research
• [Presentation] Systematics in photometric redshifts: tests > using weak lensing (2017)
  • Author(s): Surhud More
  • Organizer: HSC Weak lensing internal workshop
  • Place of Presentation: Princeton University, Princeton (USA)
  • Year and Date: 2017-02-08 – 2017-02-08
  • Int'l Joint Research
• [Presentation] Assembly bias and Splashback radius of Galaxy clusters (2016)
  • Author(s): Surhud More
  • Organizer: From theory to Lensing: Century of Gravitational lensing applications
  • Place of Presentation: Leiden University, Leiden (Netherlands)
  • Year and Date: 2016-07-14 – 2016-07-14
  • Int'l Joint Research