Searching for the Donor Stars of ULX Pulsars

Heida, Marianne; Harrison, Fiona A.; Brightman, Murray; Fürst, Felix; Stern, Daniel; Walton, D. J.

doi:10.3847/1538-4357/aafa77

Cited by 22 publications

(21 citation statements)

References 65 publications

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“…The optical counterparts of ULX pulsars are essentially undetectable with HST if the masses of the donor stars are in the range 2.5-4 M . This result is consistent with the non-detection of the counterpart of NGC 5907 ULX-1 (Sutton et al 2013a;Heida et al 2019). However, systems like NGC 7793 P13 that have a massive companion of 18-21 M in an eccentric orbit (Israel et al 2017b;Hu et al 2017) can not clearly be reproduced by a transient accretion phase of the type considered here.…”

Section: Evolutionary Tracks On the Cmdsupporting

confidence: 90%

“…This range of mass is broadly consistent with the donor of NGC 5907 ULX-1, which is thought to be an intermediate mass star in the range 2-6 M (Israel et al 2017a); although the extinction in the direction of the source is very high (Heida et al 2019). In addition, this assumption is also approximately consistent with the non-detection of the counterpart of M82 X-2, if its donor belongs to the lower end of the range obtained by Bachetti et al 2014:…”

Section: Optical Emission Of Pulsar Ulxssupporting

confidence: 77%

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Modelling optical emission of Ultra-luminous X-ray Sources accreting above the Eddington limit

Ambrosi

Zampieri

2018

Monthly Notices of the Royal Astronomical Society

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We study the evolution of binary systems of Ultra-luminous X-ray sources and compute their optical emission assuming accretion onto a black hole via a non standard, advection-dominated slim disc with an outflow. We consider systems with black holes of 20M and 100M , and donor masses between 8M and 25M . Super-critical accretion has considerable effects on the optical emission. The irradiating flux in presence of an outflow remains considerably stronger than that produced by a standard disc. However, at very high accretion rates the contribution of X-ray irradiation becomes progressively less important in comparison with the intrinsic flux emitted from the disc. After Main Sequence the evolutionary tracks of the optical counterpart on the colourmagnitude diagram are markely different from those computed for Eddington-limited accretion. Systems with stellar-mass black holes and 12 − 20M donors accreting supercritically are characterized by blue colors (F450W -F555W −0.2 : +0.1) and high luminosity (M V −4 : −6.5). Systems with more massive black holes accreting supercritically from evolved donors of similar mass have comparable colours but can reach M V −8. We apply our model to NGC 1313 X-2 and NGC 4559 X-7. Both sources are well represented by a system accreting above Eddington from a massive evolved donor. For NGC 1313 X-2 the agreement is for a ∼ 20M black hole, while NGC4559 X-7 requires a significantly more massive black hole.

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Section: Evolutionary Tracks On the Cmdsupporting

confidence: 90%

Section: Optical Emission Of Pulsar Ulxssupporting

confidence: 77%

Modelling optical emission of Ultra-luminous X-ray Sources accreting above the Eddington limit

Ambrosi

Zampieri

2018

Monthly Notices of the Royal Astronomical Society

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“…In the case of potential CE survivors among BH and NS binaries, this corresponds to ULXs with RSG donor stars. Several such systems with donor stars spectroscopically confirmed to be RSGs are known to date (Heida et al 2015(Heida et al , 2016(Heida et al , 2019bLau et al 2019). In the case of one of the sources, a pulsating ULX dubbed NGC 300 ULX-1, Heida et al (2019b) were able to model the spectrum of the optical counterpart as a sum of three components: a blue excess (likely due to X-ray irradiation), a red excess (likely due to dust), and a stellar atmosphere model of an RSG with T eff = 3650 -3900 K and log(L/L ) = 4.25 ± 0.1 (marked in Fig.…”

Section: It Has To Be Cool: Tight Link Between the Ce Donors And Red ...mentioning

confidence: 99%

It has to be cool: Supergiant progenitors of binary black hole mergers from common-envelope evolution

Klencki

Nelemans

Istrate

et al. 2021

A&A

135

122

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Common-envelope (CE) evolution in massive binary systems is thought to be one of the most promising channels for the formation of compact binary mergers. In the case of merging binary black holes (BBHs), the essential CE phase takes place at a stage when the first BH is already formed and the companion star expands as a supergiant. We aim to decipher the kinds of BH binaries with supergiant companions that could potentially evolve through and survive a CE phase. To this end, we compute envelope binding energies from detailed massive stellar models at different evolutionary stages and metallicities. We make multiple physically extreme choices of assumptions that favor easier CE ejection as well as account for recent advancements in mass-transfer stability criteria. We find that even with the most optimistic assumptions, a successful CE ejection in BH binaries is only possible if the donor is a massive convective-envelope giant, namely a red supergiant (RSG). The same is true for neutron-star binaries with massive companions. In other words, pre-CE progenitors of BBH mergers are BH binaries with RSG companions. We find that because of its influence on the radial expansion of massive giants, metallicity has an indirect but a very strong effect on the chemical profile, density structure, and the binding energies of RSG envelopes. Our results suggest that merger rates from population-synthesis models could be severely overestimated, especially at low metallicity. Additionally, the lack of observed RSGs with luminosities above log(L/L⊙) ≈ 5.6 − 5.8, corresponding to stars with M ≳ 40 M⊙, puts into question the viability of the CE channel for the formation of the most massive BBH mergers. Either such RSGs elude detection due to very short lifetimes, or they do not exist and the CE channel can only produce BBH systems with total mass ≲50 M⊙. Finally, we discuss an alternative CE scenario in which a partial envelope ejection is followed by a phase of possibly long and stable mass transfer.

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“…The color represents the number of windfed NS ULXs (i.e., L X > 10 39 erg s −1 ) in each matrix element. The cross is the location of PULX NGC 300 ULX-1 (Carpano et al 2018;Heida et al 2019b) with a donor counterpart recently discovered as a RSG star (T eff = 3650−3900 K and log(L bol /L ) = 4.25 ± 0.10, Heida et al 2019a). It is clear that in each metallicity case, the source can be reproduced roughly in all WRLOF models.…”

Section: Resultsmentioning

confidence: 86%

“…Among them, two NS ULXs are remarkable and hard to understand in the current, usual RLOF picture (Shao & Li 2015;Wiktorowicz et al 2017). One is NGC 7793 P13 (hereafter P13; Motch et al 2014;Fürst et al 2018), which is a pulsing ULX with a blue supergiant (B9Ia) of 18−23 M in a long orbital period of about 64 d. Another is the pulsing ULX source NGC 300 ULX-1 (Carpano et al 2018;Heida et al 2019b), with a red supergiant (RSG) donor (T eff = 3650−3900 K and log(L bol /L ) = 4.25 ± 0.10, Heida et al 2019a).…”

Section: Introductionmentioning

confidence: 99%

Population synthesis on ultra-luminous X-ray sources with an accreting neutron star: Wind Roche-lobe overflow cases

Zuo

Song

Xue

2021

A&A

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Very recently, wind Roche-lobe overflow (WRLOF) has been suggested as a possible mass transfer mechanism for ultra-luminous X-ray sources (ULXs) and, to date, two neutron-star (NS) ULXs (i.e., NGC 7793 P13 and NGC 300 ULX-1) are remarkable and hard to understand in the current, usual RLOF picture. In this work, we test if the two sources could fit into the WRLOF paradigm. By using an evolutionary population synthesis method, we modeled the population of NS ULXs with (super)giant donors, taking the WRLOF accretion mode into account. We find that the population of wind-fed NS ULXs in the WRLOF mode is distinct in numbers and binary parameters from that in the traditional Bondi-Hoyle-Lyttleton mode, and it is strongly metallicity dependent. The number of NS ULXs with (super)giant donors can be enhanced greatly, by one or two orders of magnitude, depending on the metallicity adopted. Sources with massive (∼15−40 M⊙) (super)giant donors dominate wind-fed NS ULXs in the very low metallicities, while sources in near solar cases are dominated by a red supergiant with a lower mass M2 < 10 M⊙ instead. Moreover, the two NS ULXs can be well reproduced in the WRLOF paradigm, which significantly enriches our understanding of the nature of ULXs and the population. We also present the current distributions of binary parameters of wind-fed NS ULXs, which may be further testified by future high-resolution optical and X-ray observations of these populations.

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Searching for the Donor Stars of ULX Pulsars

Cited by 22 publications

References 65 publications

Modelling optical emission of Ultra-luminous X-ray Sources accreting above the Eddington limit

Modelling optical emission of Ultra-luminous X-ray Sources accreting above the Eddington limit

It has to be cool: Supergiant progenitors of binary black hole mergers from common-envelope evolution

Population synthesis on ultra-luminous X-ray sources with an accreting neutron star: Wind Roche-lobe overflow cases

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