Kavli Affiliate: David P. Huenemoerder
| First 5 Authors: David P. Huenemoerder, David P. Huenemoerder, , ,
| Summary:
We present 197 ks HETG and 95 ks NuSTAR spectra of the $gamma,$Cas-type
object V750 Ara. The high-resolution X-ray spectra show that the target is
similar to other objects of this class. Data are interpreted under the
assumption that the X-rays come from an accreting white dwarf, and our analysis
implies an accretion rate of about $3times10^-11M_odotmathrmyr^-1$.
Emission lines are weak, and predominantly from hydrogen-like ions: Mg XII, Si
XIV, and S XVI. H-like and He-like Fe are both present, but Fe K$alpha$
fluorescence is weak, being significantly detected only in the NuSTAR spectrum,
but was not obviously detected in the HETG dispersed or zeroth-order spectra.
The flux was variable above a level expected by Poisson statistics. There were
no significant changes in the spectral hardness, though we are limited by lack
of soft signal below 1 keV. Emission lines of Mg and Si were strong enough to
measure velocity offsets and widths which were found to be marginally
inconsistent. The H-like Mg line is consistent with instrumental broadening
only, but shows a 300 km/s blueshift. He-like Mg and H-like Si lines have no
significant shift in velocity but are broadened by about 1000 km/s. This
suggests either different physical origins or velocity structure differing with
plasma temperature.
| Search Query: ArXiv Query: search_query=au:”David P. Huenemoerder”&id_list=&start=0&max_results=3