Bimodal Distribution of the Hyperluminous X-ray Sources

• Autorzy: Singha A. Ch. , Devi A. S.

Identyfikatory

DOI

10.32023/0001-5237/69.4.3

• Języki publikacji: EN

Abstrakty

EN

163 X-ray point sources having luminosities in excess of 10³⁸erg/s within the energy range 0.3-10.0 keV are identified in a sample of 50 galaxies observed by Chandra ACIS-S. 18 sources are found to have a total (time integrated) background flux greater than 2 cnts/arcsec² and hence excluded from the analysis to avoid any possible background/foreground contamination. The spectra of the remaining 145 sources are fitted using two spectral models - an absorbed power law and an absorbed disk blackbody. We report the discovery of four hyperluminous X-ray source candidates (X-ray luminosity: LX>10⁴¹ erg/s) - Src1, Src2, Src3 and Src22. In this study, a total of 17 hyperluminous X-ray sources were identified. The spectra of 13 sources were found to be equally represented by both the models except for three sources preferring the power law model and one source preferring the disk blackbody model. It is found that the spectra of seven hyperluminous X-ray sources are in the soft state with their inner disk temperature (kT_in) lying in the range of 0.19-0.56 keV (or power law photon index, Γ>3) and the remaining 10 hyperluminous X-ray sources are in hard state with kT_in around 1.0-2.0 keV (or power law photon index, Γ≈1.6). This shows a clear bimodal distribution of the high luminosity X-ray sources and hence they can be grouped into two distinct spectral classes. From the disk blackbody model, the black hole masses of the soft hyperluminous X-ray sources are estimated (assuming the inner disk radius, R_in≈10GM/c2) to be within ≈10³-10⁴ M☉. Also considering an anisotropic emission, for maximum beaming (η=5) with no color correction, the estimated black hole masses lie within ≈10²-10³ M☉, which is in the intermediate mass black hole range.

Słowa kluczowe

EN

galaxies: general; x-rays: binaries

• Wydawca: Copernicus Foundation for Polish Astronomy
• Czasopismo: Acta Astronomica
• Rocznik: 2019
• Tom: Vol. 69, No. 4
• Strony: 339--360
• Opis fizyczny: Bibliogr. 45 poz., rys., tab., wykr.

Twórcy

autor

Singha A. Ch.

• Assam University, Silchar, India

autor

Devi A. S.

• Assam University, Silchar, India

Bibliografia

• Anastasopoulou, K., Zezas, A., Ballo, L., and Della, C.R. 2016, MNRAS, 460, 3570.
• Barnard, R., Garcia, M., and Murray, S.S. 2013, ApJ, 772, 126.
• Begelman, M.C. 2002, ApJ, 568, L97.
• Chatterjee, et al. 2016, MNRAS, 456, 2966.
• Colbert, E.J., and Mushotzky, R.F. 1999, BAAS, 31, 873.
• Davis, S.W., Narayan R., Zhu Y.Barret D., Farrell S.A., Godet, O., Servillat, M., and Webb, N.A. 2011, ApJ, 734, 111.
• Devi, A.S., Misra, R., Agarwal, V.K., and Singh, K.Y. 2007, ApJ, 664, 458.
• Devi, A.S, Misra, R., Shanthi, K., and, Singh K.Y. 2008, ApJ, 682, 218.
• Devi, A.S., and Singh, K.Y. 2014, Astroph., and Space Sci., 354, 535.
• Fabbiano, G. 1989, Ann. Rev. Astron. Astrophys., 27, 87.
• Faber, S.M., et al. 1997, ApJ, 114, 1771.
• Farrell, S.A., Webb, N.A., Barret, D., Godet, O., and Rodrigues, J.M. 2009, Nature, 460, 73.
• Feng, H., and Kaaret, P. 2010, ApJ, 712, L169.
• Freeland, M., Kuncic, Z., Soria, R., and Bicknell, G.V. 2006, MNRAS, 372, 630.
• Gao, Y., Wang, Q.D., Appleton, P.N., and Lucas, R.A. 2003, ApJ, 596, L171.
• Gladstone, J.C., et al. 2013, ApJS, 206, 14.
• Godet, O., et al. 2012, ApJ, 752, 34.
• Gong, H., Liu, J., and Maccarone, T. 2016, ApJS, 222, 12.
• Gultekin, K, Cackett, E.M., Miller, J.M., Matteo, T.D., Markoff, S., and Richstone, D.O. 2012, ApJ, 749, 129.
• Heida, M., Jonker, P.G., Torres, M.A.P., and Mineo, S. 2012, MNRAS, 424, 1563.
• Kaaret, P., et al. 2001, MNRAS, 321, L29.
• Kaaret, P., Corbel, S., Prestwich, A.H., and Zezas, A. 2003, BAAS, 35, 608.
• Karachentsev, I.D., et al. 2002, A&A, 383, 125.
• Kaur, A., et al. 2012, A&A, 538, A49.
• King, A.R., Davies, M.B., Ward, M.J., Fabbiano, G., and Elvis, M. 2001, ApJ, 552, L109.
• Kong, A.K.H., Yang, Y.J., Hsieh, P.-Y., Mak, D.S.Y., and Pun, C.S.J. 2007, ApJ, 671, 349.
• Maccarone, T.J., Kundu, A., Zepf, S.E., and Rhode, K.L. 2010, MNRAS, 409, L84.
• Makishima, K., et al. 2000, ApJ, 535, 632.
• Matsumoto, H., et al. 2001, ApJ, 547, L25.,
• Matsumoto, H., Tatsuya, I., Tsuru, T.G., Matsushita, S., Watarai, K., and Mineshige, S. 2004, Progress of Theoretical Physics Supplement, 155, 379.
• Miller, J.M., Fabbiano, G., Miller, M.C., and Fabian, A.C. 2003, ApJ, 585, L37.
• Miller, J.M., Fabian, A.C., and Miller, M.C. 2004, ApJ, 614, L117.
• Misra, R., and Sriram, K. 2003, ApJ, 584, 981.
• Mukai, K., Still, M., Corbet, R.H.D., Kuntz, K.D., and Barnard, R. 2005, ApJ, 634, 1085.
• Paczyńsky, B., and Wiita, P.J. 1980, A&A, 88, 23.
• Pintore, F., Zampieri, L., Sutton, A.D., Roberts, T.P., Middleton, M.J., and Gladstone, J.C. 2016, MNRAS, 459, 455.
• Sanders, D.B., Mazzarella, J.M., Kim, D.-C., Surace, J.A., and Soifer, B.T. 2003, ApJ, 126, 1607.
• Shalima, P., et al. 2013, MNRAS, 434, 639.
• Singha, A.C., and Devi, A.S. 2017, Astrophysics and Space Science, 362, 223.
• Strohmayer, T.E., and Mushotzky, R.F. 2003, ApJ, 586, L61.
• Sutton, A.D., Roberts, T.P., Walton, D.J., Gladstone, J.C., and Scott, A.E. 2012, MNRAS, 423, 1154.
• Swartz, D.A., Ghosh, K.K., Tennant, A.F., and Wu, K. 2004, ApJS, 154, 519.
• Walton, D.J., et al. 2011, MNRAS, 414, 1011.
• Winter, L.M., Mushotzky, R.F., and Reynolds, C.S. 2006, ApJ, 649, 730.
• Wolter, A., and Trinchieri, G. 2004, A&A, 426, 787.

Uwagi

Opracowanie rekordu ze środków MNiSW, umowa Nr 461252 w ramach programu "Społeczna odpowiedzialność nauki" - moduł: Popularyzacja nauki i promocja sportu (2020)