X-ray spectroscopy of the candidate AGNs in Henize 2–10 and NGC 4178: likely supernova remnants

Hebbar, Pavan R.; Heinke, C. O.; Sivakoff, G. R.; Shaw, A. W.

doi:10.1093/mnras/stz553

Cited by 15 publications

(20 citation statements)

References 86 publications

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“…However, Cresci et al (2017) found that the optical emission line diagnostics at the centre of He2-10 was fully consistent with star formation and showed that the X-ray luminosity found previously was consistent with emission from supernovae. Finally, Hebbar et al (2019) have recently found that SN models of X-ray emission explain much better the observed X-ray spectrum of He2-10 than an AGN power law.…”

Section: Figure B1mentioning

confidence: 98%

The post-Herschel view of intrinsic AGN emission: constructing templates for galaxy and AGN emission at IR wavelengths

Bernhard

Tadhunter

Mullaney

et al. 2021

Monthly Notices of the Royal Astronomical Society

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Measuring the star-forming properties of AGN hosts is key to our understanding of galaxy formation and evolution. However, this topic remains debated, partly due to the difficulties in separating the infrared (i.e. 1–1000 μm) emission into AGN and star-forming components. Taking advantage of archival far-infrared data from Herschel, we present a new set of AGN and galaxy infrared templates, and introduce the spectral energy distribution fitting code iragnsep. Both can be used to measure infrared host galaxy properties, free of AGN contamination. To build these, we used a sample of 100 local (z < 0.3), low-to-high luminosity AGNs (i.e. Lbol$~\sim ~10^{42-46}$ erg s−1), selected from the 105-month Swift–BAT X-ray survey, which have archival Spitzer–IRS spectra and Herschel photometry. We first built a set of seven galaxy templates using a sample of 55 star-forming galaxies selected via infrared diagnostics. Using these templates, combined with a flexible model for the AGN contribution, we extracted the intrinsic infrared emission of our AGN sample. We further demonstrate that we can reduce the diversity in the intrinsic shapes of AGN spectral energy distributions down to a set of three AGN templates, of which two represent AGN continuum, and one represents silicate emission. Our results indicate that, on average, the contribution of AGNs to the far-infrared (λ ≳ 50 μm) is not as high as suggested by some recent work. We further show that the need for two infrared AGN continuum templates could be related to nuclear obscuration, where one of our templates appears dominated by the emission of the extended polar dust.

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Section: Figure B1mentioning

confidence: 98%

The post-Herschel view of intrinsic AGN emission: constructing templates for galaxy and AGN emission at IR wavelengths

Bernhard

Tadhunter

Mullaney

et al. 2021

Monthly Notices of the Royal Astronomical Society

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“…Several of the AGN candidates in late-type galaxies originally identified through detection of [O IV] 25.89 µm or [Ne V] 14.32 µm have since been followed up in X-rays (Gliozzi et al 2009, McAlpine et al 2011, Georgakakis et al 2011, Secrest et al 2012, Hebbar et al 2019, and in general the X-rays are found to be weaker than expected. Diffuse, thermal emission is occasionally detected when the data are of sufficient quality.…”

Section: Multi-wavelength Searches and Confusion With Star Formationmentioning

confidence: 99%

“…Higher-resolution data revealed multiple components to the central X-ray source, moving the fundamental plane mass estimate up to log M/M ∼ 7 . Subsequent work showed that the X-ray spectrum of the nuclear source is more consistent with a supernova remnant than an AGN (Hebbar et al 2019), although the possible presence of hour-scale variability would not favor this scenario , Hebbar et al 2019. There is also no evidence for AGN ionization in the galaxy center (Cresci et al 2017).…”

Section: Going Further With the Fundamental Plane Of Radio Activitymentioning

confidence: 99%

Intermediate-Mass Black Holes

Greene,

Strader,

2019

Preprint

107

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We describe ongoing searches for intermediate-mass black holes with MBH≈ 100 − 10 5 M . We review a range of search mechanisms, both dynamical and those that rely on accretion signatures. We find:• Dynamical and accretion signatures alike point to a high fraction of 10 9 − 10 10 M galaxies hosting black holes with MBH ∼ 10 5 M . In contrast, there are no solid detections of black holes in globular clusters.• There are few observational constraints on black holes in any environment with MBH ≈ 100 − 10 4 M .• Considering low-mass galaxies with dynamical black hole masses and constraining limits, we find that the MBH-σ * relation continues unbroken to MBH∼ 10 5 M , albeit with large scatter. We believe the scatter is at least partially driven by a broad range in black hole mass, since the occupation fraction appears to be relatively high in these galaxies.• We fold the observed scaling relations with our empirical limits on occupation fraction and the galaxy mass function to put observational bounds on the black hole mass function in galaxy nuclei.• We are pessimistic that local demographic observations of galaxy nuclei alone could constrain seeding mechanisms, although either highredshift luminosity functions or robust measurements of off-nuclear black holes could begin to discriminate models.

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“…First, we used the Akaike Information Criterion values (Akaike 1974), as done by Hebbar et al (2019). These values are defined as 4 :…”

Section: Evaluating the Significance Of The Ufo Componentsmentioning

confidence: 99%

Detection of a Multi-Phase Ultra-Fast Wind in the Narrow-Line Seyfert 1 Galaxy Mrk 1044

Krongold,

Longinotti,

Santos-Lleo

et al. 2021

Preprint

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We present a detailed analysis of XMM-Newton X-ray spectra of the Narrow-Line Seyfert 1 galaxy Mrk 1044. We find robust evidence for a multi-phase, ultra-fast outflow, traced by four separate components in the grating spectrum. One component has high column density and ionization state, and is outflowing at ∼ 0.15c. The other three wind components have lower temperature, lower column density, and have outflow velocities ∼ 0.08c. This wind structure is strikingly similar to that found in IRAS 17020+4544, suggesting that stratified winds may be a common feature of ultra-fast outflows. Such structure is likely produced by fluid instabilities that form when the nuclear wind shocks the ambient medium. We show that in an energy-driven wind scenario, the wind in Mrk 1044 might carry enough energy to produce significant feedback on its host galaxy. We further discuss the implications of the presence of a fast wind in yet another NLS1 galaxy with high Eddington ratio.

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X-ray spectroscopy of the candidate AGNs in Henize 2–10 and NGC 4178: likely supernova remnants

Cited by 15 publications

References 86 publications

The post-Herschel view of intrinsic AGN emission: constructing templates for galaxy and AGN emission at IR wavelengths

The post-Herschel view of intrinsic AGN emission: constructing templates for galaxy and AGN emission at IR wavelengths

Intermediate-Mass Black Holes

Detection of a Multi-Phase Ultra-Fast Wind in the Narrow-Line Seyfert 1 Galaxy Mrk 1044

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