Astrophysics and Space Science

, Volume 308, Issue 1–4, pp 505–511 | Cite as

X-ray intensity-hardness correlation and deep IR observations of the anomalous X-ray pulsar 1RXS J170849-400910

  • N. ReaEmail author
  • G. L. Israel
  • T. Oosterbroek
  • S. Campana
  • S. Zane
  • R. Turolla
  • V. Testa
  • M. Méndez
  • L. Stella
Open Access
Original Article


We report here on X-ray and IR observations of the Anomalous X-ray Pulsar (AXP) 1RXS J170849-400910. First, we report on new XMM-Newton, Swift-XRT and Chandra observations of this AXP, which confirm the intensity–hardness correlation observed in the long term X-ray monitoring of this source. These new X-ray observations show that the AXP flux is rising again, and the spectrum hardening. If the increase of the source intensity is indeed connected with the glitches and a possible bursting activity, we expect this source to enter in a bursting active phase around 2006–2007. Second, we report on deep IR observations of 1RXS J170849-400910, taken with the VLT-NACO adaptive optics, showing that there are many weak sources consistent with the AXP position. Neither star A or B, as previously proposed by different authors, might yet be conclusively recognised as the IR counterpart of 1RXS J170849-400910. Third, using Monte Carlo simulations, we re-address the calculation of the significance of the absorption line found in a phase-resolved spectrum of this source, and interpreted as a resonant scattering cyclotron feature.


Neutron stars Pulsars Magnetars X-ray 1RXS J170849-400910 


97.10.Sj 97.60.Jd 97.60.Gb 98.38.Jw 98.70.Qy 


  1. Alpar, A.: Astrophys. J. 554, 1245 (2001) CrossRefADSGoogle Scholar
  2. Anders, E., Grevesse, N.: Geochimica Cosmochimica Acta 53, 197 (1989) CrossRefADSGoogle Scholar
  3. Burgay, M., Rea, N., Israel, G.L., et al.: Mon. Not. Roy. Astron. Soc. 372, 410 (2006) CrossRefADSGoogle Scholar
  4. Camilo, F., Ransom, S., Halpern, J., et al.: Nature 442, 892 (2006) CrossRefADSGoogle Scholar
  5. Campana, S., Rea, N., Israel, G.L., Zane, S., Turolla, R.: Astron. Astrophys. 463, 1047 (2007) CrossRefADSGoogle Scholar
  6. Chatterjee, P., Hernquist, L., Narayan, R.: Astrophys. J. 534, 373 (2000) CrossRefADSGoogle Scholar
  7. Dall’Osso, S., Israel, G.L., Stella, L., et al.: Astrophys. J. 499, 485 (2003) CrossRefADSGoogle Scholar
  8. Durant, M., van Kerkwijk, M.H.: Astrophys. J. 463, 1082 (2006) CrossRefADSGoogle Scholar
  9. Duncan, R.C., Thompson, C.: Astrophys. J. 392, L9 (1992) CrossRefADSGoogle Scholar
  10. Gaensler, B.M., Stappers, B.W., Frail, D.A., et al.: Mon. Not. Roy. Astron. Soc. 318, 58 (2000) CrossRefADSGoogle Scholar
  11. Israel, G.L., Covino, S., Stella, L., et al.: Astrophys. J. 518, L107 (1999) CrossRefADSGoogle Scholar
  12. Israel, G.L., Oosterbroek, T., Stella, L., et al.: Astrophys. J. 560, L65 (2001) CrossRefADSGoogle Scholar
  13. Israel, G.L., Stella, L., Covino, S., et al.: IAU Symposium 218, preprint astro-ph/0310482 (2003a) Google Scholar
  14. Israel, G.L., Covino, S., Perna, R., et al.: Astrophys. J. 589, L93 (2003b) CrossRefADSGoogle Scholar
  15. Israel, G.L., et al.: in preparation (2006) Google Scholar
  16. Kaspi, V.M., Lackey, J.R., Chakrabarty, D.: Astrophys. J. 537, L31 (2000) CrossRefADSGoogle Scholar
  17. Kaspi, V.M., Gavriil, F.P.: Astrophys. J. 596, L71 (2003) CrossRefADSGoogle Scholar
  18. Kaspi, V.M., Gavriil, F.P., Woods, P.M., et al.: Astrophys. J. 588, L93 (2003) CrossRefADSGoogle Scholar
  19. Kaspi, V.M.: Astrophys. Space Sci., DOI  10.1007/s10509-007-9309-y (2007)
  20. Kuiper, L., Hermsen, W., den Hartog, P.R., Collmar, W.: Astrophys. J. 645, 556 (2006) CrossRefADSGoogle Scholar
  21. Mereghetti, S., Israel, G.L., Stella, L.: Mon. Not. Roy. Astron. Soc. 296, 689 (1998) CrossRefADSGoogle Scholar
  22. Protassov, R., van Dyk, D.A., Connors, A., et al.: Astrophys. J. 571, 545 (2002) CrossRefADSGoogle Scholar
  23. Rea, N., Israel, G.L., Stella, L., et al.: Astrophys. J. 586, L65 (2003) CrossRefADSGoogle Scholar
  24. Rea, N., Israel, G.L., Stella, L.: Nucl. Phys. B 132, 554 (2004) CrossRefGoogle Scholar
  25. Rea, N., Oosterbroek, T., Zane, S., et al.: Mon. Nat. Roy. Astron. Soc. 361, 710 (2005a) CrossRefADSGoogle Scholar
  26. Rea, N., Tiengo, A., Mereghetti, et al.: Astrophys. J. 627, L133 (2005b) CrossRefADSGoogle Scholar
  27. Rea, N., Zane, S., Lyutikov, M., Turolla, R.: Astrophys. Space Sci., DOI  10.1007/s10509-007-9306-1 (2007)
  28. Safi-Harb, S., West, J.: Adv. Space Res. 35(6), 1172–1176 (2005) CrossRefADSGoogle Scholar
  29. Sugizaki, M., et al.: Publ. Astron. Soc. Jpn. 49, L25–L30 (1997) ADSGoogle Scholar
  30. Thompson, C., Duncan, R.C.: Astrophys. J. 408, 194 (1993) CrossRefADSGoogle Scholar
  31. Thompson, C., Duncan, R.C.: Astrophys. J. 473, 322 (1996) CrossRefADSGoogle Scholar
  32. van Paradijs, J., Taam, R.E., van den Heuvel, E.: Astron. Astrophys. 299, L41 (1995) ADSGoogle Scholar
  33. Voges, W., et al.: IAU Circ. 6420, 2 (1996) ADSGoogle Scholar
  34. Woods, P.M., Thompson, C.: preprint astro-ph/0406133 (2004) Google Scholar
  35. Woods, P.M., et al.: Astrophys. J. 605, 378 (2004) CrossRefADSGoogle Scholar

Copyright information

© Springer Science+Business Media B.V. 2007

Authors and Affiliations

  • N. Rea
    • 1
    Email author
  • G. L. Israel
    • 2
  • T. Oosterbroek
    • 3
  • S. Campana
    • 4
  • S. Zane
    • 5
  • R. Turolla
    • 6
  • V. Testa
    • 2
  • M. Méndez
    • 1
  • L. Stella
    • 2
  1. 1.SRON Netherlands Institute for Space ResearchUtrechtThe Netherlands
  2. 2.INAF—Astronomical Observatory of RomeMonteporzio Catone (Rome)Italy
  3. 3.Science Payload and Advanced Concepts OfficeNoordwijkThe Netherlands
  4. 4.INAF—Astronomical Observatory of BreraMerate (Lc)Italy
  5. 5.Mullard Space Science LaboratoryUniversity College LondonDorking SurreyUK
  6. 6.Physics DepartmentUniversity of PaduaPadovaItaly

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