Cookies

We use cookies to ensure that we give you the best experience on our website. You can change your cookie settings at any time. Otherwise, we'll assume you're OK to continue.

Department of Physics

Staff profile

Publication details for Prof Martin Ward

Lira, P., Ward, M. J., Zezas, A. Alonso-Herrero, A. & Ueno, S. (2002). Chandra observations of the luminous infrared galaxy NGC 3256. Monthly Notices of the Royal Astronomical Society 330(2): 259-278.

Author(s) from Durham

Abstract

We present a detailed analysis of high-resolution Chandra observations of the merger system NGC 3256, the most infrared-luminous galaxy in the nearby universe. The X-ray data show that several discrete sources embedded in complex diffuse emission contribute 20 per cent of the total emission
in the 0.5–10 keV energy range). The compact sources are hard and extremely bright and their emission is probably dominated by accretion-driven processes. Both galaxy nuclei are detected with LX3–10×1040 erg s1. No evidence is found for the presence of an active nucleus in the southern nucleus, contrary to previous speculation. Once the discrete sources are removed, the diffuse component has a soft spectrum that can be modelled by the superposition of three thermal plasma components with temperatures kT=0.6, 0.9 and 3.9 keV. Alternatively, the latter component can be described as a power law with index Γ3. Some evidence is found for a radial gradient of the amount of absorption and temperature of the diffuse component. We compare the X-ray emission with optical, Hα and NICMOS images of NGC 3256 and find a good correlation between the inferred optical/near-infrared and X-ray extinctions. Although inverse Compton scattering could be important in explaining the hard X-rays seen in the compact sources associated with the nuclei, the observed diffuse emission is probably of thermal origin. The observed X-ray characteristics support a scenario in which the powerful X-ray emission is driven solely by the current episode of star formation.

References

Alonso-Herrero A., Rieke M. J., Rieke G. H., Scoville N. Z., 2000, ApJ,
532, 845
Awaki H., Ueno S., Koyama K., Tsuru T., Iwasawa K., 1996, PASJ, 48, 409
Barret D., 2001, AdSpR, in press, (preprint astro-ph/0101295)
Bregman J. N., Pildis R. A., 1992, ApJ, 398, L107
Cardelli J. A., Clayton G. C., Mathis J. S., 1989, ApJ, 345, 245
Chevalier R. A., Clegg A. W., 1985, Nat, 317, 44
Colbert E. J. M., Mushotzky R. F., 1999, ApJ, 519, 89
della Ceca R., Griffiths R. E., Heckman T. M., 1997, ApJ, 485, 581
Doyon R., Joseph R. D., Wright G. S., 1994, ApJ, 421, 101
Ebeling H., White D. A., Rangarajan F. V. N., 1999, MNRAS, accepted
Elvis M. et al., 1994, ApJSS, 95, 1
Fabbiano G., 1989, ARA&A, 87, 27
Fabbiano G., Zezas A., Murray S. S., 2001, ApJ, 554, 1035
Gehrels N., 1986, ApJ, 303, 336
Genzel R. et al., 1998, ApJ, 498, 579
George I. M., Turner T. J., Netzer H., Nandra K., Mushotzky R. F.,
Yaqoob T., 1998, ApJSS, 114, 73
Glass I. S., Moorwood A. F. M., 1985, MNRAS, 214, 429
Graham J. R., Wright G. S., Meikle W. P. S., Joseph R. D., Bode M. F.,
1984, Nat, 310, 213
Griffiths R. E., Ptak A., Feigelson E. D., Garmire G., Townsley L., Brandt
W. N., Sambruna R., Bregman J. N., 2000, Sci, 290, 1325
Heckman T. M., Armus L., Miley G. K., 1990, ApJSS, 74, 833
Heckman T. M., Dahlem M., Eales S. A., Fabbiano G., Weaver K., 1996,
ApJ, 457, 616
Heckman T. M., Armus L., Weaver K. A., Wang J., 1999, ApJ, 517, 130
Helfand D. J., Moran E. C., 2001, ApJ, 554, 27
Helou G., Khan I. R., Malek L., Boehmer L., 1988, ApJSS, 68, 151
Ho L. C., 1999, ApJ, 516, 672
Hummel E., van der Hulst J. M., 1986, A&A, 155, 151
Ishisaki et al., 1996
Iwasawa K., Fabian A. C., Almaini O., Lira P., Lawrence A., Hayashida K.,
Inoue H., 2000, MNRAS, 318, 879
Joseph R. D., Wright G. S., 1985, MNRAS, 214, 87
Kaaret P., Prestwich A. H., Zezas A., Murray S. S., Kim D.-W., Kilgard
R. E., Schlegel E. M., Ward M. J., 2001, MNRAS, 321, L29
Kotilainen J. K., Moorwood A. F. M., Ward M. J., Forber D. A., 1996,
A&A, 305, 107
Lı´pari S., Dı´az R., Taniguchi Y., Terlevich R., Dottori H., Carranza G.,
2000, AJ, 120, 645
Lı´pari S. et al., 2001, preprint (astro-ph/0007316)
Lira P., Lawrence A., Johnson R. A., 2000, MNRAS, 319, 17
Lutz D., Veilleux S., Genzel R., 1999, ApJL, 517, L13
Maiolino R., Salvati M., Bassani L., Dadina M., della Ceca R., Matt G.,
Risaliti G., Zamorani G., 1998, A&A, 338, 781
Matt G., Fabian A. C., Guainazzi M., Iwasawa K., Bassani L., Malaguti G.,
2000, MNRAS, 318, 173
Mengel S., Lehnert M. D., Thatte N., Tacconi-Garman L. E., Genzel R.,
2001, ApJ, 550, 280
Moorwood A. F. M., Oliva E., 1994, ApJ, 429, 602
Moran E. C., Lehnert M. D., Helfand D. J., 1999, ApJ, 526, 649, (MLH)
Mukai K., 1993, Legacy, 3, 21
Neff S. G., Ulvestad J. S., 2000, AJ, 120, 670
Norris R. P., Forbes D. A., 1995, ApJ, 446, 594
Pietsch W., Vogler A., Klein U., Zinnecker H., 2000, A&A, 360, 24
Pietsch W. et al., 2001, A&AL, 365, L174.
Ptak A., Serlemitsos P., Yaqoob T., Mushotzky R. F., Tsuru T., 1997, AJ,
113, 1286
Ptak A., Serlemitsos P., Yaqoob T., Mushotzky R. F., 1999, ApJSS, 120, 179
Rigopoulou D. et al., 1996, A&A, 315, L125
Roberts T. P., Warwick R. S., 2000, MNRAS, 315, 98
Rybicki G. B., Lightman A. P., 1979, Radiative Processes in Astrophysics.
Wiley-Interscience
Sanders D. B., Mirabel I. F., 1996, ARA&A, 34, 749
Sanders D. B., Soifer B. T., Elias J. H., Madore B. F., Matthews K.,
Neugebauer G., Scoville N. Z., 1988, ApJ, 325, 74
Schmitt H. R., Kinney A. L., Calzetti D., Storchi Bergmann T., 1997, AJ,
114, 592
Stanford S. A., Sargent A. I., Sanders D. B., Scoville N. Z., 1990, ApJ, 349,
492
Strickland D. K., 2001, in Chemical Enrichment of the ICM and IGM.
Preprint (astro-ph/0107116)
Strickland D. K., Ponman T. J., Stevens I. R., 1997, A&A, 320, 378
Strickland D. K., Heckman T. M.,Weaver K. A., Dahlem M., 2000, AJ, 120,
2965
Suchkov A. A., Berman V. G., Heckman T. M., Balsara D. S., 1996, ApJ,
463, 528
Wang Q. D., 1999, ApJL, 510, L139
White N. E., Nagase F., Parmar A. N., 1995, in LewinW. H. G., van Paradijs
J., van der Heuvel E. P. J., eds, X-ray Binaries. Cambridge Univ. Press,
p. 1
Zepf S. E., Ashman K. M., English J., Freeman K. C., Sharples R. M., 1999,
AJ, 118, 752
Zezas A., Fabbiano G., Rots A. H., Murray S. S., 2001, ApJ, submitted