A CHANDRA PERSPECTIVE ON GALAXY-WIDE X-RAY BINARY EMISSION AND ITS CORRELATION WITH STAR FORMATION RATE AND STELLAR MASS: NEW RESULTS FROM LUMINOUS INFRARED GALAXIES

By B. Lehmer, D. Alexander, F. Bauer, W. N. Brandt, A. Goulding, L. Jenkins, A. Ptak, T. Roberts. 2010

223 citations recorded by the source corpus.

We present new Chandra observations that complete a sample of seventeen (17) luminous infrared galaxies (LIRGs) with D < 60 Mpc and low Galactic column densities of NH ≲ 5 × 1020 cm−2. The LIRGs in our sample have total infrared (8–1000 μm) luminosities in the range of LIR≈ (1–8) × 1011 L☉. The high-resolution imaging and X-ray spectral information from our Chandra observations allow us to measure separately X-ray contributions from active galactic nuclei and normal galaxy processes (e.g., X-ray binaries and hot gas). We utilized total infrared plus UV luminosities to estimate star formation rates (SFRs) and K-band luminosities and optical colors to estimate stellar masses (M⋆) for the sample. Under the assumption that the galaxy-wide 2–10 keV luminosity (LgalHX) traces the combined emission from high-mass X-ray binaries (HMXBs) and low-mass X-ray binaries, and that the power output from these components is linearly correlated with SFR and M⋆, respectively, we constrain the relation LgalHX = αM⋆ + βSFR. To achieve this, we construct a Chandra-based data set composed of our new LIRG sample combined with additional samples of less actively star-forming normal galaxies and more powerful LIRGs and ultraluminous infrared galaxies (ULIRGs) from the literature. Using these data, we measure best-fit values of α = (9.05 ± 0.37) × 1028 erg s−1 M−1☉ and β = (1.62 ± 0.22) × 1039 erg s−1 (M☉ yr−1)−1. This scaling provides a more physically meaningful estimate of LgalHX, with ≈0.1–0.2 dex less scatter, than a direct linear scaling with SFR. Our results suggest that HMXBs dominate the galaxy-wide X-ray emission for galaxies with SFR/M⋆ ≳5.9 × 10−11 yr−1, a factor of ≈2.9 times lower than previous estimates. We find that several of the most powerful LIRGs and ULIRGs, with SFR/M⋆ ≳ 10−9 yr−1, appear to be X-ray underluminous with respect to our best-fit relation. We argue that these galaxies are likely to contain X-ray binaries residing in compact star-forming regions that are buried under thick galactic columns large enough to attenuate emission in the 2–10 keV band (NH ≳ 1023 cm−2).

Subfields: Astronomy and Astrophysics, Nuclear and High Energy Physics

View Paper: https://www.semanticscholar.org/paper/395191c9932e579a75247bf00fbca064edd3f2f5

How researchers see this paper

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In Astronomy and Astrophysics

1. D. M. Alexander
2. W. N. Brandt
3. R. Hickox
4. L. Hernquist
5. P. Hopkins
6. G. Hasinger
7. Mara Salvato
8. H. Netzer

In Nuclear and High Energy Physics

1. D. M. Alexander
2. W. N. Brandt
3. G. Hasinger
4. R. Hickox
5. T. Miyaji
6. A. Comastri
7. P. Hopkins
8. L. Hernquist

Citations in the corpus

• TOWARD A UNIFICATION OF STAR FORMATION RATE DETERMINATIONS IN THE MILKY WAY AND OTHER GALAXIES (2011, background): “In addition, Lehmer et al. (2010) show that the Milky Way is a slight (∼ 1σ) outlier from their X-ray calibration to external galaxies.”
• What drives the growth of black holes (2011, background): “…the AGNs and these AGN fractions increase to ≈ 50–80% in the LIRG and ULIRG populations when including mid-IR spectroscopy and X-ray data for the identification of AGNs (e.g., Alexander et al., 2008a; Lehmer et al., 2010; Nardini et al., 2010; Alonso-Herrero et al., 2011; Nardini & Risaliti, 2011).”
• High-mass X-ray binaries in the Milky Way (2013, background): “The X-ray luminosity of normal star forming galaxies, dominated by HMXBs and by the hot ionized inter-stellar gas, correlates well with the star formation rate (Grimm et al., 2003; Ranalli et al., 2003; Lehmer et al., 2010; Mineo et al., 2012a,b; Lutovinov et al., 2013b).”
• X-RAY BINARY EVOLUTION ACROSS COSMIC TIME (2012, methodology): “Lehmer et al. (2010) showed observational evidence that the X-ray luminosity from galaxies with SFR as high as∼ 2M⊙ yr−1 has a non-negligible contribution from LMXBs.”
• THE 4 Ms CHANDRA DEEP FIELD-SOUTH NUMBER COUNTS APPORTIONED BY SOURCE CLASS: PERVASIVE ACTIVE GALACTIC NUCLEI AND THE ASCENT OF NORMAL GALAXIES (2012, background): “…normal late-type galaxies in the local Universe, the X-ray luminosity has been shown to correlate strongly with SFR (e.g., Persic & Rephaeli 2007; Lehmer et al. 2010; Pereira-Santaella et al. 2011; Symeonidis et al. 2011; Mineo et al. 2012), and as discussed above, this correlation is observed…”
• Signatures of X-rays in the early Universe (2012, background): “…intrinsic scatter in this relation for their sample of star-forming galaxies6, while other studies in different bands have estimates which are also within a factor of few of this value (e.g. Gilfanov et al. 2004; Ranalli et al. 2003; Persic et al. 2004; Persic & Rephaeli 2007; Lehmer et al. 2010)7.”
• A CORRELATION BETWEEN STAR FORMATION RATE AND AVERAGE BLACK HOLE ACCRETION IN STAR-FORMING GALAXIES (2013, methodology): “3, we noticed that our stackedLX is at least∼ 0.7 dex higher than the Lehmer et al. (2010)LSFX in the first three bins, suggesting that theLX contribution from star formation in our stacked X-ray luminosity is less than∼ 20% in these bins.”
• X-ray emission from star-forming galaxies – I. High-mass X-ray binaries (2011, background): “During the decade following its launch several authors have discussed the X-ray emission of compact sources and its relation to the SFR of the host galaxy (Grimm, Gilfanov, & Sunyaev 2003; Ranalli, Comastri, & Setti 2003; Persic & Rephaeli 2007; Lehmer et al. 2010, and several others).”
• TOWARD THE STANDARD POPULATION SYNTHESIS MODEL OF THE X-RAY BACKGROUND: EVOLUTION OF X-RAY LUMINOSITY AND ABSORPTION FUNCTIONS OF ACTIVE GALACTIC NUCLEI INCLUDING COMPTON-THICK POPULATIONS (2014, background): “…band sample because emission from starburst galaxies is generally softer than that from AGNs, although X-ray binaries could significantly contribute to the hard X-ray luminosity in galaxies with very high star formation rates and/or stellar masses (e.g., Persic & Raphaeli 2002; Lehmer et al. 2010).”
• Cosmic X-ray surveys of distant active galaxies (2015, background): “Many researchers have established relations between X-ray luminosity and SFR for starburst/normal galaxies that lack AGNs (e.g., Bauer et al 2002; Ranalli et al 2003; Persic and Rephaeli 2007; Lehmer et al 2010; Mineo et al 2014).”
• X-ray emission from star-forming galaxies - II. Hot interstellar medium (2012, background): “1 I N T RO D U C T I O N It is well established that the number of high-mass X-ray binaries (HMXBs) and their collective luminosity scale with the star formation rate (SFR) of the host galaxy (Grimm, Gilfanov & Sunyaev 2003; Lehmer et al. 2010; Mineo, Gilfanov & Sunyaev 2012, hereafter Paper I).”
• Star Formation in the Milky Way and Nearby Galaxies (2012, background): “Calibrations of the SFR in terms of X-ray luminosity and stellar mass have been published by Colbert et al. (2004) and Lehmer et al. (2010).”
• Active galactic nuclei: what’s in a name? (2017, background): “25) and Mendez et al. (2013), who showed that MIR AGN selection only probes the upper end (& 1%) of the L/LEdd distribution compared to X-ray selection (this applies also to optically selected AGN: see Sect.”