Modeling the Local Warm∕Hot Bubble

Breitschwerdt, D.; Avillez, Miguel A. de; Baumgartner, Verena

doi:10.1063/1.3211826

Cited by 4 publications

(2 citation statements)

References 25 publications

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“…On the basis of the dynamical analysis of M33 performed by Puerari (1993), narrow features initially distributed in a spiral arm pattern would be completely smeared out by differential galactic rotation on timescales of 2 − 3 × 10 8 yr. For such narrow features to survive we need a much shorter cooling timescale (assuming radiative cooling is the dominant process) implying a filling factor much less than unity. Setting η ∼ 10 −3 gives a cooling timescale of 6 × 10 6 years, comparable to the inferred lifetime of hot bubbles observed in our own Galaxy (Egger & Aschenbach 1995;Breitschwerdt, de Avillez & Baumgartner 2009). As noted earlier, this is also roughly the timescale on which the soft Xray production maximises following the onset of a starformation episode.…”

Section: Discussionsupporting

confidence: 81%

Soft X-ray emission from the inner disc of M33

Owen

Warwick

2010

Monthly Notices of the Royal Astronomical Society

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We present a study, based on archival XMM–Newton observations, of the extended X‐ray emission associated with the inner disc of M33. After the exclusion of point sources with LX > 2 × 1035 erg s−1 (0.3–6 keV), we investigate both the morphology and spectrum of the residual X‐ray emission, comprising the integrated signal from unresolved discrete sources and diffuse components. This residual emission has a soft X‐ray spectrum which can be fitted with a two‐temperature thermal model, with kT≈ 0.2 keV and ≈0.6 keV, the cooler component accounting for the bulk of the luminosity. There is evidence that the X‐ray emitting plasma has a subsolar metal abundance. The soft X‐ray surface brightness distribution shows a strong correlation with far‐ultraviolet (FUV) emission and since the latter serves as a tracer of the inner spiral arms of M33 this is indicative of a close connection between recent star formation activity and the production of soft X‐rays. Within 3.5 kpc of the nucleus of M33, the soft X‐ray and FUV surface brightness distributions exhibit similar radial profiles. The implication is that the ratio of the soft X‐ray luminosity (0.3–2.0 keV) per unit disc area to the star formation rate per unit disc area remains fairly constant within this inner disc region. We derive a value for this ratio of 1–1.5 × 1039 erg s−1 (M⊙ yr−1)−1, which is towards the top of the range of similar estimates for several other nearby face‐on spiral galaxies (e.g. M51, M83). In the same region, the ratio of soft X‐ray luminosity to stellar mass (the latter derived from K‐band photometry) is 4 × 1028 erg s−1 M−1⊙, a factor of 5–10 higher than is typical of dwarf elliptical galaxies (e.g. M32, NGC 3379), suggesting that 10–20 per cent of the unresolved emission seen in M33 may originate in its old stellar population. The remainder of the soft X‐ray emission is found to be equally split between two spatial components, one which closely traces the spiral arms of the galaxy and the other more smoothly distributed across the inner disc of M33. The former must represent a highly clumped low‐filling‐factor component linked to sites of recent or ongoing star formation, encompassing H ii regions, X‐ray source complexes and X‐ray superbubbles, whereas the distribution of latter gives few clues as to its exact origin.

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Section: Discussionsupporting

confidence: 81%

Soft X-ray emission from the inner disc of M33

Owen

Warwick

2010

Monthly Notices of the Royal Astronomical Society

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“…The presence of 60 Fe in deep-sea measurements on Earth has triggered the study of the LB-sun interaction, see [6]. We now select some theoretical efforts that model the LB, as follows: the one-dimensional hydrocode with non-equilibrium ion evolution and dust, see [7,8]; different tests to explain the FUSE data, see [9,10]; the use of the parallel adaptive mesh refinement code EAF-PAMR, see [11]; hydrodynamical simulations of the LB, see [12]; and the study of the 3D structure of the magnetic field, see [13].…”

Section: Introductionmentioning

confidence: 99%

On the Shape of the Local Bubble

Zaninetti

2020

IJAA

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The shape of the local bubble is modeled in the framework of the thin layer approximation. The asymmetric shape of the local bubble is simulated by introducing axial profiles for the density of the interstellar medium, such as exponential, Gaussian, inverse square dependence and Navarro-Frenk-White. The availability of some observed asymmetric profiles for the local bubble allows us to match theory and observations via the observational percentage of reliability. The model is compatible with the presence of radioisotopes on Earth.

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r-Process Radioisotopes from Near-Earth Supernovae and Kilonovae

Wang

Clark

Ellis

et al. 2021

ApJ

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The astrophysical sites where r-process elements are synthesized remain mysterious: it is clear that neutron star mergers (kilonovae (KNe)) contribute, and some classes of core-collapse supernovae (SNe) are also possible sources of at least the lighter r-process species. The discovery of 60Fe on the Earth and Moon implies that one or more astrophysical explosions have occurred near the Earth within the last few million years, probably SNe. Intriguingly, 244Pu has now been detected, mostly overlapping with 60Fe pulses. However, the 244Pu flux may extend to before 12 Myr ago, pointing to a different origin. Motivated by these observations and difficulties for r-process nucleosynthesis in SN models, we propose that ejecta from a KN enriched the giant molecular cloud that gave rise to the Local Bubble, where the Sun resides. Accelerator mass spectrometry (AMS) measurements of 244Pu and searches for other live isotopes could probe the origins of the r-process and the history of the solar neighborhood, including triggers for mass extinctions, e.g., that at the end of the Devonian epoch, motivating the calculations of the abundances of live r-process radioisotopes produced in SNe and KNe that we present here. Given the presence of 244Pu, other r-process species such as 93Zr, 107Pd, 129I, 135Cs, 182Hf, 236U, 237Np, and 247Cm should be present. Their abundances and well-resolved time histories could distinguish between the SN and KN scenarios, and we discuss prospects for their detection in deep-ocean deposits and the lunar regolith. We show that AMS 129I measurements in Fe–Mn crusts already constrain a possible nearby KN scenario.

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Modeling the Local Warm∕Hot Bubble

Cited by 4 publications

References 25 publications

Soft X-ray emission from the inner disc of M33

Soft X-ray emission from the inner disc of M33

On the Shape of the Local Bubble

r-Process Radioisotopes from Near-Earth Supernovae and Kilonovae

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