Does High-density or Mass Help Star Clusters Produce X-Ray Binaries in Star-forming Galaxies?

ABSTRACT We explore X-ray emission from a sample of 18 He ii λ1640 emitting star-forming galaxies at z ∼ 2.3–3.6 from the VANDELS survey in the Chandra Deep Field South, to set constraints on the role of X-ray sources in powering the He ii emission. We find that 4 He ii emitters have tentative detections with S/N ∼ 2 and have X-ray luminosities, LX = 1.5−4.9 × 1041 erg s−1. The stacked luminosity of all 18 He ii emitters is 2.6 × 1041 erg s−1, and that of a subset of 13 narrow He ii emitters (FHWM(He ii) < 1000 km s−1) is 3.1 × 1041 erg s−1. We also measure stacked LX for non-He ii emitters through bootstrapping of matched samples, and find LX = 2.5 × 1041 erg s−1, which is not significantly different from LX measured for He ii emitters. The LX per star formation rate for He ii emitters (log (LX/SFR) ∼ 40.0) and non-emitters (log (LX/SFR) ∼ 39.9) are also comparable and in line with the redshift evolution and metallicity dependence predicted by models. Due to the non-significant difference between the X-ray emission from galaxies with and without He ii, we conclude that X-ray binaries or weak or obscured active galactic nuclei are unlikely to be the dominant producers of He ii ionizing photons in VANDELS star-forming galaxies at z ∼ 3. Given the comparable physical properties of both He ii emitters and non-emitters reported previously, alternative He ii ionizing mechanisms such as localized low-metallicity stellar populations, Pop-III stars, etc. may need to be explored.

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X-ray sources in Galactic globular clusters and old open clusters

Proceedings of the International Astronomical Union ◽

10.1017/s1743921319007981 ◽

2019 ◽

Vol 14 (S351) ◽

pp. 367-376

Author(s):

Maureen van den Berg

Keyword(s):

Globular Clusters ◽

Cataclysmic Variables ◽

Star Clusters ◽

Open Clusters ◽

Encounter Rate ◽

X Ray ◽

Low Mass ◽

New Perspective ◽

X Ray Binaries ◽

Cluster Age

AbstractThe features and make up of the population of X-ray sources in Galactic star clusters reflect the properties of the underlying stellar environment. Cluster age, mass, stellar encounter rate, binary frequency, metallicity, and maybe other properties as well, determine to what extent we can expect a contribution to the cluster X-ray emission from low-mass X-ray binaries, millisecond pulsars, cataclysmic variables, and magnetically active binaries. Sensitive X-ray observations withXMM-Newton and certainlyChandra have yielded new insights into the nature of individual sources and the effects of dynamical encounters. They have also provided a new perspective on the collective X-ray properties of clusters, in which the X-ray emissivities of globular clusters and old open clusters can be compared to each other and to those of other environments. I will review our current understanding of cluster X-ray sources, focusing on star clusters older than about 1 Gyr, illustrated with recent results.

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High-mass X-ray binaries in nearby metal-poor galaxies: on the contribution to nebular He ii emission

Monthly Notices of the Royal Astronomical Society ◽

10.1093/mnras/staa586 ◽

2020 ◽

Vol 494 (1) ◽

pp. 941-957 ◽

Cited By ~ 6

Author(s):

Peter Senchyna ◽

Daniel P Stark ◽

Jordan Mirocha ◽

Amy E Reines ◽

Stéphane Charlot ◽

...

Keyword(s):

Formation Rate ◽

Stellar Atmospheres ◽

High Mass ◽

Spectral Energy ◽

X Ray ◽

Star Forming ◽

High Ionization ◽

Binary Evolution ◽

Joint Contribution ◽

X Ray Binaries

ABSTRACT Despite significant progress both observationally and theoretically, the origin of high-ionization nebular He ii emission in galaxies dominated by stellar photoionization remains unclear. Accretion-powered radiation from high-mass X-ray binaries (HMXBs) is still one of the leading proposed explanations for the missing He+-ionizing photons, but this scenario has yet to be conclusively tested. In this paper, we present nebular line predictions from a grid of photoionization models with input spectral energy distributions containing the joint contribution of both stellar atmospheres and a multicolour disc model for HMXBs. This grid demonstrates that HMXBs are inefficient producers of the photons necessary to power He ii, and can only boost this line substantially in galaxies with HMXB populations large enough to power X-ray luminosities of 1042 erg s−1 per unit star formation rate (SFR). To test this, we assemble a sample of 11 low-redshift star-forming galaxies with high-quality constraints on both X-ray emission from Chandra and He ii emission from deep optical spectra, including new observations with the MMT. These data reveal that the HMXB populations of these nearby systems are insufficient to account for the observed He ii strengths, with typical X-ray luminosities or upper limits thereon of only 1040–1041 erg s−1 per SFR. This indicates that HMXBs are not the dominant source of He+ ionization in these metal-poor star-forming galaxies. We suggest that the solution may instead reside in revisions to stellar wind predictions, softer X-ray sources, or very hot products of binary evolution at low metallicity.

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The High Mass X-ray binaries in star-forming galaxies

Proceedings of the International Astronomical Union ◽

10.1017/s1743921318007627 ◽

2018 ◽

Vol 14 (S346) ◽

pp. 332-336

Author(s):

M. Celeste Artale ◽

Nicola Giacobbo ◽

Michela Mapelli ◽

Paolo Esposito

Keyword(s):

Luminosity Function ◽

High Mass ◽

Population Synthesis ◽

Host Galaxies ◽

X Ray ◽

Star Forming ◽

Star Formation In Galaxies ◽

Binary Evolution ◽

X Ray Binaries ◽

The Universe

AbstractThe high mass X-ray binaries (HMXBs) provide an exciting framework to investigate the evolution of massive stars and the processes behind binary evolution. HMXBs have shown to be good tracers of recent star formation in galaxies and might be important feedback sources at early stages of the Universe. Furthermore, HMXBs are likely the progenitors of gravitational wave sources (BH–BH or BH–NS binaries that may merge producing gravitational waves). In this work, we investigate the nature and properties of HMXB population in star-forming galaxies. We combine the results from the population synthesis model MOBSE (Giacobbo & Mapelli 2018a) together with galaxy catalogs from EAGLE simulation (Schaye et al. 2015). Therefore, this method describes the HMXBs within their host galaxies in a self-consistent way. We compute the X-ray luminosity function (XLF) of HMXBs in star-forming galaxies, showing that this methodology matches the main features of the observed XLF.

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STACKING STAR CLUSTERS IN M51: SEARCHING FOR FAINT X-RAY BINARIES

The Astrophysical Journal ◽

10.1088/0004-637x/763/2/96 ◽

2013 ◽

Vol 763 (2) ◽

pp. 96 ◽

Cited By ~ 3

Author(s):

N. Vulic ◽

P. Barmby ◽

S. C. Gallagher

Keyword(s):

Star Clusters ◽

X Ray ◽

X Ray Binaries

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Do star clusters form in a completely mass-segregated way?

Astronomy and Astrophysics ◽

10.1051/0004-6361/201834265 ◽

2019 ◽

Vol 626 ◽

pp. A79 ◽

Cited By ~ 10

Author(s):

Václav Pavlík ◽

Pavel Kroupa ◽

Ladislav Šubr

Keyword(s):

Star Clusters ◽

Point Of View ◽

High Mass ◽

Orion Nebula ◽

Energy Redistribution ◽

X Ray ◽

Star Forming ◽

Independent Observations ◽

Mass Segregation ◽

Rule Out

Context. ALMA observations of the Serpens South star-forming region suggest that stellar protoclusters may be completely mass segregated at birth. Independent observations also suggest that embedded clusters form segregated by mass. Aims. As the primordial mass segregation seems to be lost over time, we aim to study on which timescale an initially perfectly mass-segregated star cluster becomes indistinguishable from an initially not mass-segregated cluster. As an example, the Orion Nebula Cluster (ONC) is also discussed. Methods. We used N-body simulations of star clusters with various masses and two different degrees of primordial mass segregation. We analysed their energy redistribution through two-body relaxation to quantify the time when the models agree in terms of mass segregation, which sets in only dynamically in the models that are primordially not mass segregated. A comprehensive cross-matched catalogue combining optical, infrared, and X-ray surveys of ONC members was also compiled and made available. Results. The models evolve to a similar radial distribution of high-mass stars after the core collapse (about half a median two-body relaxation time, trh) and become observationally indistinguishable from the point of view of mass segregation at time τv ≈ 3.3 trh. In the case of the ONC, using the distribution of high-mass stars, we may not rule out either evolutionary scenario (regardless of whether they are initially mass segregated). When we account for extinction and elongation of the ONC, as reported elsewhere, an initially perfectly mass-segregated state seems to be more consistent with the observed cluster.

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An X-Ray View of Interacting Binaries Outside The Galaxy

International Astronomical Union Colloquium ◽

10.1017/s0252921100151693 ◽

2004 ◽

Vol 194 ◽

pp. 3-6

Author(s):

Andrea H. Prestwich

Keyword(s):

Supernova Remnants ◽

Luminosity Function ◽

Local Group ◽

Spiral Galaxies ◽

High Mass ◽

X Ray ◽

Star Forming ◽

Star Forming Regions ◽

Low Mass ◽

X Ray Binaries

AbstractChandra and XMM-Newton are revolutionizing our understanding of compact binaries in external galaxies, allowing us to study sources in detail in Local Group Galaxies and study populations in more distant systems. In M31 the X-ray luminosity function depends on the local stellar population in the sense that areas with active star formation have more high luminosity sources, and a higher overall source density (Kong. Di Stefano. Garcia, & Greiner 2003). This result is also true in galaxies outside the Local Group; starburst galaxies have flatter X-ray luminosity functions than do spiral galaxies which are in turn flatter than elliptical galaxies. These observational results suggest that the high end of the luminosity function in star forming regions is dominated by short-lived high mass X-ray binaries.In Chandra Cycle 2 we started a Large Project to survey a sample of 11 nearby (< 10Mpc) face-on spiral galaxies. We find that sources can be approximately classified on the basis of their X-ray color into low mass X-ray binaries, high mass X-ray binaries and supersoft sources. There is an especially interesting class of source that has X-ray colors softer (“redder”) than a typical low mass X-ray binary source, but not so extreme as supersoft sources. Most of these are probably X-ray bright supernova remnants, but some may be a new type of black hole accretor. Finally, when we construct a luminosity function of sources selecting only sources with low mass X-ray binary colors (removing soft sources) we find that there is a dip or break probably associated with the Eddington luminosity for a neutron star.

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THE CONNECTION BETWEEN X-RAY BINARIES AND STAR CLUSTERS IN NGC 4449

The Astrophysical Journal ◽

10.1088/0004-637x/741/2/86 ◽

2011 ◽

Vol 741 (2) ◽

pp. 86 ◽

Cited By ~ 16

Author(s):

Blagoy Rangelov ◽

Andrea H. Prestwich ◽

Rupali Chandar

Keyword(s):

Star Clusters ◽

X Ray ◽

X Ray Binaries

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A ULX in NGC 4559: A “Mini-Cartwheel” Scenario?

International Astronomical Union Colloquium ◽

10.1017/s0252921100151905 ◽

2004 ◽

Vol 194 ◽

pp. 57-59 ◽

Cited By ~ 1

Author(s):

R. Soria ◽

M. S. Cropper ◽

M. W. Pakull

Keyword(s):

Galactic Disk ◽

Large Diameter ◽

Galaxy Interactions ◽

X Ray ◽

Star Forming ◽

Satellite Galaxy ◽

Low Metallicity ◽

High Velocity Clouds ◽

The Impact ◽

X Ray Binaries

AbstractWe have studied the peculiar environment around a ULX in NGC 4559 (with Lx ≈ 2 x 1040 erg s–1 and MBH ≳ 50M⊙). The X-ray source is located near the rim of a young (age < 30 Myr), large (diameter ≈ 700 pc) ring-like star forming complex possibly triggered by the impact of a dwarf satellite galaxy through the gas-rich outer disk of NGC 4559. We speculate that galaxy interactions (including the infall of high-velocity clouds and satellites on a galactic disk) and low-metallicity environments offer favourable conditions for the formation of compact remnants more massive than “standard” X-ray binaries, and accreting from a massive Roche-lobe filling companion.

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