The BeppoSAX 0.1-18 keV spectrum of the bright atoll source GX 9+1: an indication of the source distance

Details The BeppoSAX 0.1-18 keV spectrum of the bright atoll source GX 9+1: an indication of the source distance The BeppoSAX 0.1-18 keV spectrum of the bright atoll source GX 9+1: an indication of the source distance

Aug 2005

adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2005a%26a...439..575i&link_type=abstract

Astronomy and Astrophysics, Volume 439, Issue 2, August IV 2005, pp.575-583

Astronomy and Astrophysics

Astrophysics

5

Accretion, Accretion Discs, Stars: Individual: Gx 9+1, Stars:, Neutron, X-Ray: Stars, X-Ray: Binaries, X-Ray: General

Scientific paper

We report the results of a long, 350 ks, BeppoSAX observation of the bright atoll source GX 9+1 in the 0.12-18 keV energy range. During this observation GX 9+1 showed a large count rate variability in its lightcurve. From its color-color diagram we selected six zones and extracted the source energy spectrum from each zone. We find that the model, composed of a blackbody plus a Comptonized component absorbed by an equivalent hydrogen column of ~1.4 × 1022 cm-2, fits the spectra in the energy range 1-18 keV well; however, below 1 keV a soft excess is present. We find that the spectrum of GX 9+1, in the 0.12-18 keV energy range, is well fitted by the model above, if we use an equivalent hydrogen column of ~0.8 × 1022 cm-2, together with several absorption edges from ionized matter (O VII, O VIII, Ne IX, Ar XVII, and Ca XX) and an absorption line from Si XIV. From the study of these features we deduce that the electron density of the plasma and the equivalent hydrogen column density associated with the ionized matter is ~1012 cm-3 and ~1023 cm-2, respectively, at a distance from the central object of r ˜ 1011 cm, while at larger distances the equivalent hydrogen column density associated to the ionized matter decreases down to ~1022 cm-2. The value of the equivalent hydrogen column of ~0.8 × 1022 cm-2 associated to the interstellar matter implies that GX 9+1 is at a distance of 5 kpc, and not 8.5-10 kpc as usually assumed. This result implies that the atoll source GX 9+1 does not emit at the Eddington limit, as supposed until now, but has a luminosity of 6 × 1037 erg/s in the 0.1-18 keV energy range, typical of LMXBs belonging to the bright atoll class.

Affiliated with

Also associated with

No associations

Rating

The BeppoSAX 0.1-18 keV spectrum of the bright atoll source GX 9+1: an indication of the source distance does not yet have a rating. At this time, there are no reviews or comments for this scientific paper.

If you have personal experience with The BeppoSAX 0.1-18 keV spectrum of the bright atoll source GX 9+1: an indication of the source distance, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and The BeppoSAX 0.1-18 keV spectrum of the bright atoll source GX 9+1: an indication of the source distance will most certainly appreciate the feedback.

Rate now

Comments { 0 }

Profile ID: LFWR-SCP-O-1343212