English (United Kingdom)

https://curated-unify.zendy.io/wp-json/zendy-region/v1/featured_content/oa?rat=en

https://curated-unify.zendy.io/wp-json/zendy-region/v1/highlighted_journal/

Global: Zendy Plus annual

Presents the access of premium content as premium feature

Premium Content

Presents the keyphrase highlighting as premium feature

Keyphrase Highlighting

Presents the summarisation as premium feature

Summarisation

Insights

Presents the pdf analysis as premium feature

PDF Analysis

Presents the zaia usage as premium feature

ZAIA

Global: Zendy Tools annual

Global: Zendy Free Plan

Global: Zendy Tools monthly

Global: Zendy Plus monthly

With the XMM-Newton and Suzaku observations, for the first time, we acquiredbroad-band spectra of two unidentified X-ray sources towards the Galacticbulge: 1RXS J180556.1$-$343818 and 1RXS J173905.2$-$392615. The 1RXSJ180556.1$-$343818 spectrum in the $0.3$-$7$ keV band was explained by X-rayemission originated from an optically-thin thermal plasma with temperatures of$0.5$ and $1.7$ keV. The estimated absorption column density of $N_{\rm H} \sim4 \times 10^{20}$ cm$^{-2}$ was significantly smaller than the Galactic HIcolumn density towards the source. A candidate of its optical counterpart, HD321269, was found within $4''$. In terms of the X-ray properties and thepositional coincidence, it is quite conceivable that 1RXS J180556.1$-$343818 isan active G giant. We also found a dim X-ray source that was positionallyconsistent with 1RXS J173905.2$-$392615. Assuming that the X-ray spectrum canbe reproduced with an absorbed optically-thin thermal plasma model with $kT =1.6$ keV, the X-ray flux in the $0.5$-$8$ keV band was $8.7 \times 10^{-14}$erg s$^{-1}$ cm$^{-2}$, fainter by a factor of $\sim 7$ than that of 1RXSJ173905.2$-$392615 during the ROSAT observation. The follow-up observations weconducted revealed that these two sources would belong to the Galactic disk,rather than the Galactic bulge.

publications of the astronomical society of japan

XMM-Newton and Suzaku Spectroscopic Studies of Unidentified X-ray  Sources towards the Galactic Bulge: 1RXS J180556.1$-$343818 and 1RXS  J173905.2$-$392615