Spectral Properties of X-ray Binaries in Centaurus A

Mark J. Burke; Somak Raychaudhury; Ralph P. Kraft; Thomas J. Maccarone; Nicola J. Brassington; Martin J. Hardcastle; Jouni Kainulainen; Kristin A. Woodley; Joanna L. Goodger; Gregory R. Sivakoff; William R. Forman; Christine Jones; Stephen S. Murray; Mark Birkinshaw; Judith H. Croston; Daniel A. Evans; Marat Gilfanov; Andres Jordan; Craig L. Sarazin; Rasmus Voss; Diana M. Worrall; Zhongli Zhang

doi:10.1088/0004-637X/766/2/88

Spectral Properties of X-ray Binaries in Centaurus A

Mark J. Burke^*, Somak Raychaudhury, Ralph P. Kraft, Thomas J. Maccarone, Nicola J. Brassington, Martin J. Hardcastle, Jouni Kainulainen, Kristin A. Woodley, Joanna L. Goodger, Gregory R. Sivakoff, William R. Forman, Christine Jones, Stephen S. Murray, Mark Birkinshaw, Judith H. Croston, Daniel A. Evans, Marat Gilfanov, Andres Jordan, Craig L. Sarazin, Rasmus VossDiana M. Worrall, Zhongli Zhang

^*Corresponding author for this work

School of Physics

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Abstract

We present a spectral investigation of X-ray binaries (XBs) in NGC 5128 (Cen A), using six 100 ks Chandra observations taken over two months in 2007. We divide our sample into thermally and non-thermally dominated states based on the behavior of the fitted absorption column N _H, and present the spectral parameters of sources with L_x ≳ 2 × 10 ³⁷ erg s^-1. The majority of sources are consistent with being neutron star low-mass X-ray binaries (NS LMXBs) and we identify three transient black hole (BH) LMXB candidates coincident with the dust lane, which is the remnant of a small late-type galaxy. Our results also provide tentative support for the apparent "gap" in the mass distribution of compact objects between ∼2-5 M _⊙. We propose that BH LMXBs are preferentially found in the dust lane, and suggest this is because of the younger stellar population. The majority (∼70%-80%) of potential Roche lobe filling donors in the Cen A halo are ≳ 12 Gyr old, while BH LMXBs require donors ≳ 1 M _⊙ to produce the observed peak luminosities. This requirement for more massive donors may also explain recent results that claim a steepening of the X-ray luminosity function with age at L_x ≥ 5 × 10³⁸ erg s^-1 for the XB population of early-type galaxies; for older stellar populations, there are fewer stars ≳ 1 M _⊙, which are required to form the more luminous sources. © 2013. The American Astronomical Society. All rights reserved..

Original language	English
Article number	88
Pages (from-to)	88-102
Number of pages	15
Journal	Astrophysical Journal
Volume	766
Issue number	2
Early online date	13 Mar 2013
DOIs	https://doi.org/10.1088/0004-637X/766/2/88
Publication status	Published - 1 Apr 2013

Bibliographical note

Accepted for publication in ApJ

Keywords

black hole physics
galaxies: elliptical and lenticular, cD
galaxies: individual (Centaurus A, NGC 5128)
X-rays: binaries
X-rays: galaxies
DISC INSTABILITY MODEL
BLACK-HOLE ACCRETION
EARLY-TYPE GALAXIES
GLOBULAR-CLUSTER
LUMINOSITY FUNCTION
PARTICLE-ACCELERATION
NEUTRON-STAR
NGC 5128
OBSERVATIONAL APPEARANCE
MASS-DISTRIBUTION

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Burke, M. J., Raychaudhury, S., Kraft, R. P., Maccarone, T. J., Brassington, N. J., Hardcastle, M. J., Kainulainen, J., Woodley, K. A., Goodger, J. L., Sivakoff, G. R., Forman, W. R., Jones, C., Murray, S. S., Birkinshaw, M., Croston, J. H., Evans, D. A., Gilfanov, M., Jordan, A., Sarazin, C. L., ... Zhang, Z. (2013). Spectral Properties of X-ray Binaries in Centaurus A. Astrophysical Journal, 766(2), 88-102. Article 88. https://doi.org/10.1088/0004-637X/766/2/88

@article{0f1dc98a4ab441df8af357870e5944c3,

title = "Spectral Properties of X-ray Binaries in Centaurus A",

abstract = "We present a spectral investigation of X-ray binaries (XBs) in NGC 5128 (Cen A), using six 100 ks Chandra observations taken over two months in 2007. We divide our sample into thermally and non-thermally dominated states based on the behavior of the fitted absorption column N H, and present the spectral parameters of sources with Lx ≳ 2 × 10 37 erg s-1. The majority of sources are consistent with being neutron star low-mass X-ray binaries (NS LMXBs) and we identify three transient black hole (BH) LMXB candidates coincident with the dust lane, which is the remnant of a small late-type galaxy. Our results also provide tentative support for the apparent {"}gap{"} in the mass distribution of compact objects between ∼2-5 M ⊙. We propose that BH LMXBs are preferentially found in the dust lane, and suggest this is because of the younger stellar population. The majority (∼70%-80%) of potential Roche lobe filling donors in the Cen A halo are ≳ 12 Gyr old, while BH LMXBs require donors ≳ 1 M ⊙ to produce the observed peak luminosities. This requirement for more massive donors may also explain recent results that claim a steepening of the X-ray luminosity function with age at Lx ≥ 5 × 1038 erg s-1 for the XB population of early-type galaxies; for older stellar populations, there are fewer stars ≳ 1 M ⊙, which are required to form the more luminous sources. {\textcopyright} 2013. The American Astronomical Society. All rights reserved..",

keywords = "black hole physics, galaxies: elliptical and lenticular, cD, galaxies: individual (Centaurus A, NGC 5128), X-rays: binaries, X-rays: galaxies, DISC INSTABILITY MODEL, BLACK-HOLE ACCRETION, EARLY-TYPE GALAXIES, GLOBULAR-CLUSTER, LUMINOSITY FUNCTION, PARTICLE-ACCELERATION, NEUTRON-STAR, NGC 5128, OBSERVATIONAL APPEARANCE, MASS-DISTRIBUTION",

author = "Burke, {Mark J.} and Somak Raychaudhury and Kraft, {Ralph P.} and Maccarone, {Thomas J.} and Brassington, {Nicola J.} and Hardcastle, {Martin J.} and Jouni Kainulainen and Woodley, {Kristin A.} and Goodger, {Joanna L.} and Sivakoff, {Gregory R.} and Forman, {William R.} and Christine Jones and Murray, {Stephen S.} and Mark Birkinshaw and Croston, {Judith H.} and Evans, {Daniel A.} and Marat Gilfanov and Andres Jordan and Sarazin, {Craig L.} and Rasmus Voss and Worrall, {Diana M.} and Zhongli Zhang",

note = "Accepted for publication in ApJ",

year = "2013",

month = apr,

day = "1",

doi = "10.1088/0004-637X/766/2/88",

language = "English",

volume = "766",

pages = "88--102",

journal = "Astrophysical Journal",

issn = "0004-637X",

publisher = "American Astronomical Society",

number = "2",

}

Burke, MJ, Raychaudhury, S, Kraft, RP, Maccarone, TJ, Brassington, NJ, Hardcastle, MJ, Kainulainen, J, Woodley, KA, Goodger, JL, Sivakoff, GR, Forman, WR, Jones, C, Murray, SS, Birkinshaw, M, Croston, JH, Evans, DA, Gilfanov, M, Jordan, A, Sarazin, CL, Voss, R, Worrall, DM & Zhang, Z 2013, 'Spectral Properties of X-ray Binaries in Centaurus A', Astrophysical Journal, vol. 766, no. 2, 88, pp. 88-102. https://doi.org/10.1088/0004-637X/766/2/88

TY - JOUR

T1 - Spectral Properties of X-ray Binaries in Centaurus A

AU - Burke, Mark J.

AU - Raychaudhury, Somak

AU - Kraft, Ralph P.

AU - Maccarone, Thomas J.

AU - Brassington, Nicola J.

AU - Hardcastle, Martin J.

AU - Kainulainen, Jouni

AU - Woodley, Kristin A.

AU - Goodger, Joanna L.

AU - Sivakoff, Gregory R.

AU - Forman, William R.

AU - Jones, Christine

AU - Murray, Stephen S.

AU - Birkinshaw, Mark

AU - Croston, Judith H.

AU - Evans, Daniel A.

AU - Gilfanov, Marat

AU - Jordan, Andres

AU - Sarazin, Craig L.

AU - Voss, Rasmus

AU - Worrall, Diana M.

AU - Zhang, Zhongli

N1 - Accepted for publication in ApJ

PY - 2013/4/1

Y1 - 2013/4/1

N2 - We present a spectral investigation of X-ray binaries (XBs) in NGC 5128 (Cen A), using six 100 ks Chandra observations taken over two months in 2007. We divide our sample into thermally and non-thermally dominated states based on the behavior of the fitted absorption column N H, and present the spectral parameters of sources with Lx ≳ 2 × 10 37 erg s-1. The majority of sources are consistent with being neutron star low-mass X-ray binaries (NS LMXBs) and we identify three transient black hole (BH) LMXB candidates coincident with the dust lane, which is the remnant of a small late-type galaxy. Our results also provide tentative support for the apparent "gap" in the mass distribution of compact objects between ∼2-5 M ⊙. We propose that BH LMXBs are preferentially found in the dust lane, and suggest this is because of the younger stellar population. The majority (∼70%-80%) of potential Roche lobe filling donors in the Cen A halo are ≳ 12 Gyr old, while BH LMXBs require donors ≳ 1 M ⊙ to produce the observed peak luminosities. This requirement for more massive donors may also explain recent results that claim a steepening of the X-ray luminosity function with age at Lx ≥ 5 × 1038 erg s-1 for the XB population of early-type galaxies; for older stellar populations, there are fewer stars ≳ 1 M ⊙, which are required to form the more luminous sources. © 2013. The American Astronomical Society. All rights reserved..

AB - We present a spectral investigation of X-ray binaries (XBs) in NGC 5128 (Cen A), using six 100 ks Chandra observations taken over two months in 2007. We divide our sample into thermally and non-thermally dominated states based on the behavior of the fitted absorption column N H, and present the spectral parameters of sources with Lx ≳ 2 × 10 37 erg s-1. The majority of sources are consistent with being neutron star low-mass X-ray binaries (NS LMXBs) and we identify three transient black hole (BH) LMXB candidates coincident with the dust lane, which is the remnant of a small late-type galaxy. Our results also provide tentative support for the apparent "gap" in the mass distribution of compact objects between ∼2-5 M ⊙. We propose that BH LMXBs are preferentially found in the dust lane, and suggest this is because of the younger stellar population. The majority (∼70%-80%) of potential Roche lobe filling donors in the Cen A halo are ≳ 12 Gyr old, while BH LMXBs require donors ≳ 1 M ⊙ to produce the observed peak luminosities. This requirement for more massive donors may also explain recent results that claim a steepening of the X-ray luminosity function with age at Lx ≥ 5 × 1038 erg s-1 for the XB population of early-type galaxies; for older stellar populations, there are fewer stars ≳ 1 M ⊙, which are required to form the more luminous sources. © 2013. The American Astronomical Society. All rights reserved..

KW - black hole physics

KW - galaxies: elliptical and lenticular, cD

KW - galaxies: individual (Centaurus A, NGC 5128)

KW - X-rays: binaries

KW - X-rays: galaxies

KW - DISC INSTABILITY MODEL

KW - BLACK-HOLE ACCRETION

KW - EARLY-TYPE GALAXIES

KW - GLOBULAR-CLUSTER

KW - LUMINOSITY FUNCTION

KW - PARTICLE-ACCELERATION

KW - NEUTRON-STAR

KW - NGC 5128

KW - OBSERVATIONAL APPEARANCE

KW - MASS-DISTRIBUTION

UR - http://www.scopus.com/inward/record.url?scp=84875465181&partnerID=8YFLogxK

U2 - 10.1088/0004-637X/766/2/88

DO - 10.1088/0004-637X/766/2/88

M3 - Article (Academic Journal)

SN - 0004-637X

VL - 766

SP - 88

EP - 102

JO - Astrophysical Journal

JF - Astrophysical Journal

IS - 2

M1 - 88

ER -

Spectral Properties of X-ray Binaries in Centaurus A

Abstract

Bibliographical note

Keywords

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Research in planetary physics, astrophysics and cosmology at Bristol

Cite this

Spectral Properties of X-ray Binaries in Centaurus A

Abstract

Bibliographical note

Keywords

Access to Document

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Other files and links

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Projects

Research in planetary physics, astrophysics and cosmology at Bristol

Cite this