Multiple Temperature Components of the Hot Circumgalactic Medium of the Milky Way

Das, Sanskriti; Mathur, S.; Gupta, Anjali; Nicastro, F.; Krongold, Y.

doi:10.3847/1538-4357/ab5846

Cited by 46 publications

(42 citation statements)

References 50 publications

(86 reference statements)

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“…Moreover, it agrees with previous indications that the missing baryons are likely significantly correlated with galaxies and groups (e.g. Nicastro et al 2018;Lim et al 2020;Das et al 2019Das et al , 2020.…”

Section: Quantitative Comparison In the Sdss Footprintsupporting

confidence: 91%

Testing the Strong Equivalence Principle. II. Relating the External Field Effect in Galaxy Rotation Curves to the Large-Scale Structure of the Universe

Chae,

Desmond,

Lelli

et al. 2021

Preprint

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Theories of modified gravity generically violate the strong equivalence principle, so that the internal dynamics of a self-gravitating system in free fall depends on the strength of the external gravitational field (the external field effect). We fit rotation curves (RCs) from the SPARC database with a model inspired by Milgromian dynamics (MOND), which relates the outer shape of a RC to the external Newtonian field from the large-scale baryonic matter distribution through a dimensionless parameter e N . We obtain a > 4σ statistical detection of the external field effect (i.e. e N > 0 on average), confirming previous results. We then locate the SPARC galaxies in the cosmic web of the nearby Universe and find a striking contrast in the fitted e N values for galaxies in underdense versus overdense regions. Galaxies in an underdense region between 22 and 45 Mpc from the celestial axis in the northern sky have RC fits consistent with e N 0, while those in overdense regions adjacent to the CfA2 great wall and the Perseus-Pisces supercluster return e N that are a factor of two larger than the median for SPARC galaxies. We also calculate independent estimates of e N from galaxy survey data and find that they agree with the e N inferred from the RCs within the uncertainties, the chief uncertainty being the spatial distribution of baryons not contained in galaxies or clusters.

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Section: Quantitative Comparison In the Sdss Footprintsupporting

confidence: 91%

Testing the Strong Equivalence Principle. II. Relating the External Field Effect in Galaxy Rotation Curves to the Large-Scale Structure of the Universe

Chae,

Desmond,

Lelli

et al. 2021

Preprint

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“…The SDXB spectrum is usually described by a three-component model consisting of: 1) a foreground component of LB and SWCX, modeled as an unabsorbed thermal plasma emission in CIE, 2) a background component of CXB modeled with an absorbed power-law, and 3) the MW halo emission, modeled as an equilibrium thermal plasma absorbed by the cold gas in the Galactic disk (the halo emission toward the Galactic center is dominated by the bubbles; [1]). Recently we found that in few observations an additional absorbed thermal component and/or enhanced Ne abundance is required to explain the excess emission near 0.7 − 0.9 keV in the Suzaku [11] and XMM-Newton [10] SDXB spectra.…”

Section: Spectral Analysismentioning

confidence: 99%

Paradigm shift in understanding the Galactic eROSITA Bubbles

Gupta¹,

Mathur²,

Kingsbury³

et al. 2022

Preprint

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The magnificent bubbles at the Galactic center provide a great channel to understand the effects of feedback on galaxy evolution. The newly discovered eROSITA bubbles show enhanced X-ray emission from the shells around bubbles. Previous works assumed that the X-ray emitting gas in the shells has a single temperature component and that they trace the shock-heated lower-temperature Galactic halo gas. Here we show that the thermal structure of the eROSITA bubble shells is more complex. Using Suzaku observations we find with high confidence that the X-ray emission from the shells is best described by a twotemperature thermal model, one near Galaxy's virial temperature at kT ≈ 0.2 keV and the other at super-virial temperatures ranging between kT = 0.4 − 1.1 keV. Furthermore, we show that temperatures of the virial and super-virial components are similar in the shells and in the ambient medium, although the emission measures are significantly higher in the shells. We argue that the X-ray bright eROSITA bubble shells are the signature of compressed isothermal radiative shocks. The age of the bubbles is constrained to 70-130 Myr. This expansion timescale, as well as the observed non-solar Ne/O and Mg/O ratios, favor the stellar feedback models for the formation of the Galactic bubbles, settling a long-standing debate on the origin of the Galactic bubbles.

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“…Gatuzz & Churazov (2018) studied Ne ix absorption alongside O vii and O viii, focussing on the hot CGM and the ISM. The Milky Way CGM has also been probed with soft X-ray emission (e.g., Kuntz & Snowden 2000;Miller & Bregman 2015;Das et al 2019), and studied using combinations of emission and absorption (e.g., Bregman & Lloyd-Davies 2007;Gupta et al 2014;Miller & Bregman 2015;Gupta et al 2017;Das et al 2019).…”

Section: Introductionmentioning

confidence: 99%

“…Another exception is the Milky Way. The halo of our own Galaxy has been studied using X-ray line emission, often in combination with X-ray absorption lines (e.g., Bregman & Lloyd-Davies 2007;Gupta et al 2014;Miller & Bregman 2015;Das et al 2019). Other studies focussed on absorption lines (e.g., Kuntz & Snowden 2000;Hodges-Kluck et al 2016;Gatuzz & Churazov 2018).…”

Section: Introductionmentioning

confidence: 99%

The warm-hot circumgalactic medium around EAGLE-simulation galaxies and its detection prospects with X-ray and UV line absorption

Wijers

Schaye

Oppenheimer

2020

Monthly Notices of the Royal Astronomical Society

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We use the EAGLE cosmological simulation to study the distribution of baryons, and FUV (O vi), EUV (Ne viii) and X-ray (O vii, O viii, Ne ix, and Fe xvii) line absorbers, around galaxies and haloes of mass $\, \rm {M}_{\rm {200c}}= 10^{11}$–$10^{14.5} \, \rm {M}_{\odot }$ at redshift 0.1. EAGLE predicts that the circumgalactic medium (CGM) contains more metals than the interstellar medium across halo masses. The ions we study here trace the warm-hot, volume-filling phase of the CGM, but are biased towards temperatures corresponding to the collisional ionization peak for each ion, and towards high metallicities. Gas well within the virial radius is mostly collisionally ionized, but around and beyond this radius, and for O vi, photo-ionization becomes significant. When presenting observables we work with column densities, but quantify their relation with equivalent widths by analysing virtual spectra. Virial-temperature collisional ionization equilibrium ion fractions are good predictors of column density trends with halo mass, but underestimate the diversity of ions in haloes. Halo gas dominates the highest column density absorption for X-ray lines, but lower-density gas contributes to strong UV absorption lines from O vi and Ne viii. Of the O vii (O viii) absorbers detectable in an Athena X-IFU blind survey, we find that 41 (56) per cent arise from haloes with $\, \rm {M}_{\rm {200c}}= 10^{12.0 \rm {-}13.5} \, \rm {M}_{\odot }$. We predict that the X-IFU will detect O vii (O viii) in 77 (46) per cent of the sightlines passing $\, \rm {M}_{\star }= 10^{10.5 \rm {-}11.0} \, \rm {M}_{\odot }$ galaxies within $100 \, \rm {pkpc}$ (59 (82) per cent for $\, \rm {M}_{\star }> 10^{11.0} \, \rm {M}_{\odot }$). Hence, the X-IFU will probe covering fractions comparable to those detected with the Cosmic Origins Spectrograph for O vi.

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Multiple Temperature Components of the Hot Circumgalactic Medium of the Milky Way

Cited by 46 publications

References 50 publications

Testing the Strong Equivalence Principle. II. Relating the External Field Effect in Galaxy Rotation Curves to the Large-Scale Structure of the Universe

Testing the Strong Equivalence Principle. II. Relating the External Field Effect in Galaxy Rotation Curves to the Large-Scale Structure of the Universe

Paradigm shift in understanding the Galactic eROSITA Bubbles

The warm-hot circumgalactic medium around EAGLE-simulation galaxies and its detection prospects with X-ray and UV line absorption

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