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An Fe Xxvi Absorption Line in the Persistent Spectrum of the Dipping Low Mass X-ray Binary Ia 1744-361
| Content Provider | Semantic Scholar |
|---|---|
| Author | Gavriil, Fotis P. |
| Copyright Year | 2009 |
| Abstract | We report on Chandra X-ray Observatory (CXO) High-Energy Transmission Grating (HETG) spectra of the dipping Low Mass X-ray Binary (LMXB) 1A 1744-361 during its July 2008 outburst. We find that its persistent emission is well modeled by a blackbody (kT 1.0 keV) plus power-law (F 1.7) with an absorption edge at 7.6 keV. In the residuals of the combined spectrum we find a significant absorption line at 6.961±0.002 keV, consistent with the Fe XXVI (hydrogen-like Fe) 2 1 transition. We place an upper limit on the velocity of a redshifted flow of v < 221 km s -1 . We find an equivalent width for the line of 27±3 eV, from which we determine a column density of 7±1 x 10 17 em-2 via a curve-of-growth analysis. Using XSTAR simulations, we place a lower limit on the ionization parameter of > 103.6 erg cm s -1 . The properties of this line are consistent with those observed in other dipping LMXBs. Using Rossi X-ray Timing Explorer (RXTE) data accumulated during this latest outburst we present an updated color-color diagram which clearly shows that IA 1744-361 is an "atoll" source. Finally, using additional dips found in the RXTE and CXO data we provide an updated orbital period estimate of 52±5 minutes. Subject, headings: line: identification — binaries: general — stars: individual(lA 1744-361) — stars: neutron — X-rays: binaries — X-rays: stars |
| File Format | PDF HTM / HTML |
| Alternate Webpage(s) | https://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/20090038691.pdf |
| Language | English |
| Access Restriction | Open |
| Content Type | Text |
| Resource Type | Article |
