Identification of Absorption Lines of Heavy Metals in the Wavelength Range 0.97–1.32 μm
Noriyuki Matsunaga, Daisuke Taniguchi, Mingjie Jian, Yuji Ikeda, Kei Fukue, Sohei Kondo, Satoshi Hamano, Hideyo Kawakita, Naoto Kobayashi, Shogo Otsubo, Hiroaki Sameshima, Keiichi Takenaka, Takuji Tsujimoto, Ayaka Watase, Chikako Yasui, Tomohiro Yoshikawa
Abstract
Abstract Stellar absorption lines of heavy elements can give us various insights into the chemical evolution of our Galaxy and other nearby galaxies. Recently developed spectrographs for the near-infrared wavelengths are becoming more and more powerful at producing a large number of high-quality spectra, but identification and characterization of the absorption lines in the infrared range remain to be fulfilled. We searched for lines of elements heavier than the iron group, i.e., those heavier than Ni, in the Y (9760–11100 Å) and J (11600–13200 Å) bands. We considered the lines in three catalogs, i.e., the Vienna Atomic Line Database, the compilation by R. Kurucz, and the list published in 1999 by Meléndez & Barbuy. Candidate lines were selected based on synthetic spectra, and the confirmation was done by using WINERED spectra of 13 giants and supergiants within FGK spectral types (spanning 4000–7200 K in the effective temperature). We have detected lines of Zn i , Sr ii , Y ii , Zr i , Ba ii , Sm ii , Eu ii , and Dy ii , in the order of atomic number. Although the number of the lines is small, 23 in total, they are potentially useful diagnostic lines of the Galactic chemical evolution, especially in those regions for which interstellar extinction hampers detailed chemical analyses with spectra in shorter wavelengths. We also report the detection of lines whose presence was not predicted by the synthetic spectra created with the above three line lists.