Abstract
Abstract
We present the integral field spectroscopic observations of ionized gas (Hα and [N II]) using the PCWI, along with deep CO(2–1) observations by the
‵
U
¯
‵
u
¯
receiver on JCMT for AGC 102004. The velocity field of Hα shows an anomalous distribution in the northwestern (NW) disk. The Hα spectrum is well-fitted by two Gaussian components, and the weak Gaussian component is dominated by the anomalous Hα in the NW disk. The Gaussian fit center of Hα emission is offset by +24.2 km s−1 from the systemic velocity obtained from the H i emission. We derive the gas-phase metallicity, 12+log(O/H), using [N II]λ6583/Hα ratio as a proxy. The mean value of 12+log(O/H) is 8.30 ± 0.19 over the whole galaxy. The metallicity in the outer disk is lower than the detection limit of 7.72, indicating the metallicity gradient exists in AGC 102004. We speculate a minor/mini-merger event could have happened to the NW disk. CO(2–1) emission has nondetection in AGC 102004, reaching a noise level of 0.33 mK smoothed to 30 km s−1. The upper limit of molecular gas mass in AGC 102004 is 2.1 × 107
M
⊙ with X
CO = 3.02 × 1020 cm−2 (K km s−1)−1. The
M
H
2
/M
H
I
corr
of AGC 102004 is lower than 0.0037 and lower than that of normal galaxies.
Publisher
American Astronomical Society