XTE J1701-407 INTEGRAL and Swift observations

ATel #1791; S. Soldi, V. Beckmann, D. Eckert (ISDC/Geneva Univ.), C. Ferrigno (ISDC/IAAT), G. Belanger, E. Kuulkers (ESA/ESAC), M. D. Caballero-Garcia (IoA Cambridge), J. Chenevez (DTU/NSI), M. Falanga, L. Prat (CEA/Saclay), J.-C. Leyder (Univ. Liege), J. M. Miller (Univ. Michigan), S. Piraino (INAF-IASF Palermo), K. Pottschmidt (CRESST/GSFC/UMBC), L. Sidoli (INAF-IASF Milano), A. Bazzano, L. Natalucci, P. Ubertini (INAF-IASF Roma), K. Watanabe (FGCU)
on 20 Oct 2008; 09:34 UT
Credential Certification: Volker Beckmann (Volker.Beckmann@obs.unige.ch)

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INTEGRAL has observed the Galactic center region starting September 18, 2008 through a long key program (KP) and several ToO observations of H1743-322. In the course of these observations, the neutron star LMXB XTE J1701-407 (Markwardt et al. 2008, ATel #1569 and ATel #1616, ATel #1621) has been detected by IBIS/ISGRI in the 20-80 keV band. The source was always outside the field of view of the X-ray monitor JEM-X. The evolution of the source flux shows that the long outburst of XTE J1701-407 (GCN Circ. #7985, ATel #1618), which started July 2008 and was described by Linares et al. 2008 (arXiv:0808.3950v2), is still on-going:

  
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 Obs |  Rev  |    Start time    | Exp [ks] | Flux(20-40 keV) [mCrab] 
  
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 KP  |  724  | 2008-09-18T11:55 |    34    |      11 ± 2 
  
 KP  |  725  | 2008-09-20T02:45 |   130    |      14 ± 1 
  
 KP  |  726  | 2008-09-23T12:36 |    99    |      12 ± 2 
  
 ToO |  731  | 2008-10-10T05:19 |    20    |      17 ± 3 
  
 ToO |  732  | 2008-10-10T21:35 |    72    |      16 ± 2 
  
 KP  |  733  | 2008-10-15T22:59 |    31    |      12 ± 2 
  
 ToO |  734  | 2008-10-17T20:59 |   118    |      16 ± 1 
  
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In the latest observation, the source was also detected in the 40-80 keV band with 14 ± 2 mCrab. Simultaneous to this observation a Swift ToO was performed, starting at 2008-10-18T14:27 with an on-source time of 1.7 ksec. The combined spectrum of Swift/XRT and IBIS/ISGRI (33 ksec) can be represented by an absorbed power law with intrinsic NH = 2.2e22 1/cm^2 and photon index 2.1 ± 0.1. The model flux in the 2-50 keV band is 3e-10 erg/cm^2/sec. Assuming a maximum distance of 6 kpc (Linares et al. 2008), this results in a luminosity of L(2-50 keV) = 1.3e+36 erg/sec.

INTEGRAL will continue to observe the Galactic center region over the next revolutions. The data of the INTEGRAL ToO observations of H1743-322 are public.

Download INTEGRAL ToO data