Resonant scattering in NGC 5044 and NGC 5813

Plaa, J. de; Zhuravleva, Irina; Werner, Norbert; Kaastra, J. S.; Churazov, E.; Grange, Yan

doi:10.1063/1.3696146

Cited by 3 publications

(4 citation statements)

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“…The observed Z, especially Fe, are lower than that predicted by models, which represents an old problem that has been alleviated in more recent investigations but still clearly persists. Contributing factors to it include residual uncertainties in the derived abundances, for example, due to the degeneracy of metallicity and emission measure and the multitemperature thermal structure of the ISM (de Plaa et al ; Kim ); dust depletion of metals (Lakhchaura et al ; Panagoulia et al ); and incomplete mixing of SNIa's ejecta (Matsushita et al ; Tang & Wang ). Based on the present results, the CGM infall can also have an important effect.…”

Section: Discussionmentioning

confidence: 99%

Metal abundances in the MACER simulations of the hot interstellar medium

et al. 2020

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Hot plasma is the dominant phase of the interstellar medium of early‐type galaxies. It can originate from stellar mass losses, residual gas from the formation epoch, and accretion from outside the galaxies. Its evolution is linked to the dynamical structure of the host galaxy, to the supernova and active galactic nuclei (AGN) feedback, and to (late‐epoch) star formation in a way that has yet to be fully understood. Important clues about the origin and evolution of the hot gas come from the abundances of heavy metals that have been studied with increasing detail through XMM‐Newton and Chandra. We present recent high‐resolution hydrodynamical simulations of the hot gas evolution that include the above processes, where several chemical species, originating in asymptotic giant branch stars and supernovae of types Ia and II, have also been considered. The high resolution, of few parsecs in the central galactic region, allows us to track the metal enrichment, transportation, and dilution throughout the galaxy. The comparison of model results with observed abundances demonstrates good agreement for the region enriched by the AGN wind but also shows discrepancies for the diffuse hot gas; the latter indicates the need for a revision of standard assumptions and/or the importance of neglected effects due to the dust and/or residual uncertainties in deriving abundances from the X‐ray spectra.

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Section: Discussionmentioning

confidence: 99%

Metal abundances in the MACER simulations of the hot interstellar medium

et al. 2020

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“…We point out that there is currently a controversy about the correct numerical values of the (I λ17.05 + I λ17.10 )/I λ15.01 ratios in optically thin plasma, which can result in up to 30% systematic uncertainty in derived values of the turbulence velocities between different models (de Plaa et al 2012). We chose to compare our measurements to the model of Doron & Behar (2002) because it closely agrees with the observational Fe line ratios in several IGM spectra where low Fe absorption is expected (see, e.g., the multisource study by Werner et al 2009).…”

Section: Fe XVII Measurementsmentioning

confidence: 99%

“…The optical thickness of a given line is proportional to the product of its ion column density and transition oscillator strength, which for the Fe xvii ion 15.01, 17.05, and 17.10 Å lines are about 10 0 , 10 −1 , and 10 −7 , respectively (see, e.g., de Plaa et al 2012). The line optical thickness also depends upon the gas velocity distribution in the line of sight because a photon is only absorbed if its energy closely matches the energy of the transition in the absorbing ion's frame of reference.…”

Section: Fe XVII Measurementsmentioning

confidence: 99%

Observations of asymmetric velocity fields and gas cooling in the NGC 4636 galaxy group X-ray halo

Ahoranta

Finoguenov

Pinto

et al. 2016

A&A

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Aims. This study aims to probe the thermodynamic properties of the hot intragroup medium (IGM) plasma in the core regions of the NGC 4636 galaxy group by detailed measurements of several emission lines and their relative intensities. Methods. We analyzed deep XMM-Newton Reflection Grating Spectrometer (RGS) data in five adjacent spectral regions in the central parts of the NGC 4636 galaxy group. We examined the suppression of the Fe xvii resonance line (15.01 Å) as compared to the forbidden lines of the same ion (17.05 Å and 17.10 Å). The presence and radial dependence of the cooling flow was investigated through spectral modeling. Parallel analysis with deep Chandra Advances CCD Imaging Spectrometer (ACIS) data was conducted to gain additional information about the thermodynamical properties of the IGM.Results. The plasma at the group center to the north shows efficient Fe xvii ion resonant scattering, yielding (I λ17.05 + I λ17.10 )/I λ15.01 line ratios up to 2.9 ± 0.4, corresponding to about twice the predicted line ratio. In contrast, no resonant scattering was detected at the south side. The regions featuring resonant scattering coincide with those embodying large amounts of cool (kT 0.4 keV) gas phases, and the spectral imprints of cooling gas with a total mass deposition rate of ∼0.8 M yr −1 within the examined region of 2.4 × 5.0 . Conclusions. We interpret the results as possible evidence of asymmetric turbulence distribution in the NGC 4636 IGM: turbulence dominates the gas dynamics to the south, while collective gas motions characterize the dynamics to the north. X-ray images show imprints of energetic AGN at both sides, yet we find evidence of turbulence heating at the south and gas cooling at the north of the core. We infer that the observed asymmetry may be the result of the specific observation angle to the source, or arise from the turbulence driven by core sloshing at south side.

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“…Indeed, the formal fit errors are known to be smaller than the actual fit errors (e.g. de Plaa et al 2017). An example of disagreement can also be found in the subsolar abundances found by Cohen et al (2008) and Zhekov & Palla (2007) for HD 111123: even though they analysed the same dataset, the Zhekov & Palla (2007) abundances of O, Ne, and Mg are a factor of two smaller than those of Cohen et al (2008); the origin of this discrepancy is unknown.…”

Section: Global Fitsmentioning

confidence: 99%

B stars seen at high resolution by XMM-Newton

Cazorla

Nazé

2017

A&A

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We report on the properties of 11 early B stars observed with gratings on board XMM-Newton and Chandra, thereby doubling the number of B stars analysed at high resolution. The spectra typically appear soft, with temperatures of 0.2-0.6 keV, and moderately bright (log[L X /L BOL ] ∼ −7) with lower values for later type stars. In line with previous studies, we also find an absence of circumstellar absorption, negligible line broadening, no line shift, and formation radii in the range 2 -7 R ⋆ . From the X-ray brightnesses, we derived the hot mass-loss rate for each of our targets and compared these values to predictions or values derived in the optical domain: in some cases, the hot fraction of the wind can be non-negligible. The derived X-ray abundances were compared to values obtained from the optical data, with a fair agreement found between them. Finally, half of the sample presents temporal variations, either in the long-term, short-term, or both. In particular, HD 44743 is found to be the second example of an X-ray pulsator, and we detect a flare-like activity in the binary HD 79351, which also displays a high-energy tail and one of the brightest X-ray emissions in the sample.

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Resonant scattering in NGC 5044 and NGC 5813

Cited by 3 publications

References 0 publications

Metal abundances in the MACER simulations of the hot interstellar medium

Metal abundances in the MACER simulations of the hot interstellar medium

Observations of asymmetric velocity fields and gas cooling in the NGC 4636 galaxy group X-ray halo

B stars seen at high resolution by XMM-Newton

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