Ionized and Cold Gas Components in Low Surface Brightness Galaxy AGC 102004
No Thumbnail Available
Date
2024
Journal Title
Journal ISSN
Volume Title
Publisher
Abstract
We present the integral field spectroscopic observations of ionized gas (H alpha and [N II]) using the PCWI, along with deep CO(2-1) observations by the '(U) over bar'(u) over bar receiver on JCMT for AGC 102004. The velocity field of H alpha shows an anomalous distribution in the northwestern (NW) disk. The H alpha spectrum is well-fitted by two Gaussian components, and the weak Gaussian component is dominated by the anomalous H alpha in the NW disk. The Gaussian fit center of H alpha 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]lambda 6583/H alpha 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 x 107 M-circle dot with X-CO = 3.02 x 1020 cm(-2) (K km s(-1))(-1). The MH2 /M-HI(corr) of AGC 102004 is lower than 0.0037 and lower than that of normal galaxies.