Browsing by Author "Chen P"

Now showing 1 - 2 of 2
  • Thumbnail Image
    Item
    Firm size and the political cycle premium
    (EmeraldInsight, 2015) Malone CB; Anderson H; Chen P
    We investigate the role of firm size in generating political cycle outcomes. Like in the U.S., New Zealand’s political cycle premium is driven by small firms; however, the results are opposite. In New Zealand, periods governed by the right of the political spectrum produce significantly higher stock returns than those from the left and this finding is primarily driven by small firms who perform particularly poorly under left-of-centre governments. We identify several explanations for the poor performance in small firms. These firms were relatively heavily affected by the move to an open, deregulated economy; they were also less able to cope with tight monetary conditions, and periods of sharply falling inflation.
  • Thumbnail Image
    Item
    OGLE-2015-BLG-0845L: a low-mass M dwarf from the microlensing parallax and xallarap effects
    (Oxford University Press, 2024-09-01) Hu Z; Zhu W; Gould A; Udalski A; Sumi T; Chen P; Calchi Novati S; Yee JC; Beichman CA; Bryden G; Carey S; Fausnaugh M; Scott Gaudi B; Henderson CB; Shvartzvald Y; Wibking B; Mroz P; Skowron J; Poleski R; Szymanski MK; Soszynski I; Pietrukowicz P; Kozłowski S; Ulaczyk K; Rybicki KA; Iwanek P; Wrona M; Gromadzki MG; Abe F; Barry R; Bennett DP; Bhattacharya A; Bond IA; Fujii H; Fukui A; Hamada R; Hirao Y; Silva SI; Itow Y; Kirikawa R; Koshimoto N; Matsubara Y; Miyazaki S; Muraki Y; Olmschenk G; Ranc C; Rattenbury NJ; Satoh Y; Suzuki D; Tomoyoshi M; Tristram PJ; Vandorou A; Yama H; Yamashita K
    We present the analysis of the microlensing event OGLE-2015-BLG-0845, which was affected by both the microlensing parallax and xallarap effects. The former was detected via the simultaneous observations from the ground and Spitzer, and the latter was caused by the orbital motion of the source star in a relatively close binary. The combination of these two effects led to a mass measurement of the lens object, revealing a low-mass (0.14 ± 0.05 M) M dwarf at the bulge distance (7.6 ± 1.0 kpc). The source binary consists of a late F-type subgiant and a K-type dwarf of ∼ 1.2 and ∼ 0.9M, respectively, and the orbital period is 70 ± 10 d. OGLE-2015-BLG-0845 is the first single-lens event in which the lens mass is measured via the binarity of the source. Given the abundance of binary systems as potential microlensing sources, the xallarap effect may not be a rare phenomenon. Our work thus highlights the application of the xallarap effect in the mass determination of microlenses, and the same method can be used to identify isolated dark lenses.