Figure 1: The imaging data taken with the Hubble Space Telescope (HST) of LAE 221724+001716 (left). The shape of LAE 221724+001716 in the HST image is peculiar and looks like a "magatama", an ancient Japanese amulet made of stone (right). (Credit: Ehime University)
Figure 2: The shape and scale of the galaxies composing the magatama galaxy.
a) Reference figure for the physical scales of the foreground and background galaxies. Using the physical scale of 10 kilo light years, the red lines represent the foreground galaxy while the blue lines represent the background galaxy. (Credit: Ehime University)
b) The schematic view of LAE 221724+001716's shape (top) and imaging data taken with the Subaru Telescope (bottom left and middle) and the HST (bottom right). While both emissions detected in NB359 and NB497 images were originally thought to come from LAE 221724+001716, later observations revealed that most of the emission in NB359 comes from a foreground galaxy and that two distinct galaxies overlap and lie in an extremely close line of sight in the sky. 1 arcsecond (arcsec) is equal to 1/3600 of arc (part of a curve or circle). (Credit: Ehime University)
Figure 3: Examples of gravitational lensing
a) Schematic view of how gravitational lensing works. If there is not a foreground gravitational source, the black lines show how the light travels from the distant object and reaches Earth. If a gravitational source lies between Earth and the distant object, the red lines show how the light path bends and travels around the gravitational source. As a result, the distant object is amplified and another path of light reaches us. (Credit: Ehime University)
b) Schematic view of LAE 221724+001716's configuration. Due to the gravitational lensing effect, light from the actual location of background galaxy 11.6 billion light years distant from Earth bends around the foreground galaxy that is 9.9 billion light years distant. As a result, the red-filled star (separated by 0.6 arcseconds from the foreground galaxy) shows the position at which the background galaxy was observed. (Credit: Ehime University)
Figure 4: The relationship between the gravitational amplification factor and the stellar mass of the foreground galaxy. The red vertical line represents the upper limit of the estimated stellar mass, which provides an upper limit to the gravitational amplification. (Credit: Ehime University)
These results are published in the April 1st 2013 issue of the Astrophysical Journal, as "A Gravitational Lens Model for the Lya Emitter, LAE 221724+001716 at z=3.1 in the SSA 22 Field", Y. Nakahiro, Y. Taniguchi, A. K. Inoue, Y. Shioya, M. Kajisawa, M. A. R. Kobayashi, I. Iwata, Y. Matsuda, T. Hayashino, A. R. Tanaka, & K. Hamada.
Members of the research team are:
- Yuya Nakahiro (Ehime University)
- Yoshiaki Taniguchi (Ehime University)
- Akio K. Inoue (Osaka Sangyo University)
- Yasuhiro Shioya (Ehime University)
- Masaru Kajisawa (Ehime University)
- Masakazu A. R. Kobayashi (Ehime University)
- Ikuru Iwata (National Astronomical Observatory of Japan)
- Yuichi Matsuda (National Astronomical Observatory of Japan)
- Yuki Hayashino (Tohoku University)
- Ayaka R. Tanaka (Ehime University)
- Katsuhiko Hamada (Ehime University)
This research was supported by the Japan Society for the Promotion of Science
(Nos. 17253001, 19340046, 23244031, 23654068, 23684010, and 24244018).