scholarly journals The fates of the circumgalactic medium in the FIRE simulations

2020 ◽  
Vol 494 (3) ◽  
pp. 3581-3595 ◽  
Author(s):  
Zachary Hafen ◽  
Claude-André Faucher-Giguère ◽  
Daniel Anglés-Alcázar ◽  
Jonathan Stern ◽  
Dušan Kereš ◽  
...  
Keyword(s):  
Mass Range ◽  
The Other ◽  
Lower Mass ◽  
Poor Predictor ◽  
Central Galaxy ◽  
Circumgalactic Medium ◽  
Cool Gas ◽  
Halo Masses ◽  
Ultimate Fate ◽  
In Fire

ABSTRACT We analyse the different fates of the circumgalactic medium (CGM) in FIRE-2 cosmological simulations, focusing on the redshifts z = 0.25 and 2 representative of recent surveys. Our analysis includes 21 zoom-in simulations covering the halo mass range $M_{\rm h}(z=0) \sim 10^{10} \!-\! 10^{12} \rm {\,M}_\odot$. We analyse both where the gas ends up after first leaving the CGM (its ‘proximate’ fate) and its location at z = 0 (its ‘ultimate’ fate). Of the CGM at z = 2, about half is found in the ISM or stars of the central galaxy by z = 0 in Mh(z = 2) ∼ 5 × 1011 M⊙ haloes, but most of the CGM in lower mass haloes ends up in the intergalactic medium (IGM). This is so even though most of the CGM in Mh(z = 2) ∼ 5 × 1010 M⊙ haloes first accretes on to the central galaxy before being ejected into the IGM. On the other hand, most of the CGM mass at z = 0.25 remains in the CGM by z = 0 at all halo masses analysed. Of the CGM gas that subsequently accretes on to the central galaxy in the progenitors of Mh(z = 0) ∼ 1012 M⊙ haloes, most of it is cool (T ∼ 104 K) at z = 2 but hot (∼Tvir) at z ∼ 0.25, consistent with the expected transition from cold mode to hot mode accretion. Despite the transition in accretion mode, at both z = 0.25 and $2 \, {\gtrsim} 80{{\ \rm per\ cent}}$ of the cool gas in $M_{\rm h} \gtrsim 10^{11} \rm {M}_\odot$ haloes will accrete on to a galaxy. We find that the metallicity of CGM gas is typically a poor predictor of both its proximate and ultimate fates. This is because there is in general little correlation between the origin of CGM gas and its fate owing to substantial mixing while in the CGM.

scholarly journals The origins of the circumgalactic medium in the FIRE simulations

2019 ◽  
Vol 488 (1) ◽  
pp. 1248-1272 ◽  
Author(s):  
Zachary Hafen ◽  
Claude-André Faucher-Giguère ◽  
Daniel Anglés-Alcázar ◽  
Jonathan Stern ◽  
Dušan Kereš ◽  
...  
Keyword(s):  
Mass Range ◽  
Physical Mechanisms ◽  
Stellar Feedback ◽  
Multiple Origins ◽  
Metal Diffusion ◽  
Central Galaxy ◽  
The Galaxy ◽  
Circumgalactic Medium ◽  
Cool Gas ◽  
Halo Gas

ABSTRACT We use a particle tracking analysis to study the origins of the circumgalactic medium (CGM), separating it into (1) accretion from the intergalactic medium (IGM), (2) wind from the central galaxy, and (3) gas ejected from other galaxies. Our sample consists of 21 FIRE-2 simulations, spanning the halo mass range Mh ∼ 1010–1012 M⊙, and we focus on z = 0.25 and z = 2. Owing to strong stellar feedback, only ∼L⋆ haloes retain a baryon mass $\gtrsim\! 50\hbox{ per cent}$ of their cosmic budget. Metals are more efficiently retained by haloes, with a retention fraction $\gtrsim\! 50\hbox{ per cent}$. Across all masses and redshifts analysed $\gtrsim \!60\hbox{ per cent}$ of the CGM mass originates as IGM accretion (some of which is associated with infalling haloes). Overall, the second most important contribution is wind from the central galaxy, though gas ejected or stripped from satellites can contribute a comparable mass in ∼L⋆ haloes. Gas can persist in the CGM for billions of years, resulting in well mixed-halo gas. Sightlines through the CGM are therefore likely to intersect gas of multiple origins. For low-redshift ∼L⋆ haloes, cool gas (T < 104.7 K) is distributed on average preferentially along the galaxy plane, however with strong halo-to-halo variability. The metallicity of IGM accretion is systematically lower than the metallicity of winds (typically by ≳1 dex), although CGM and IGM metallicities depend significantly on the treatment of subgrid metal diffusion. Our results highlight the multiple physical mechanisms that contribute to the CGM and will inform observational efforts to develop a cohesive picture.

scholarly journals Properties of the circumgalactic medium in cosmic ray-dominated galaxy haloes

2020 ◽  
Vol 496 (4) ◽  
pp. 4221-4238 ◽  
Author(s):  
Suoqing Ji ◽  
T K Chan ◽  
Cameron B Hummels ◽  
Philip F Hopkins ◽  
Jonathan Stern ◽  
...  
Keyword(s):  
Cosmic Ray ◽  
Pressure Balance ◽  
Thermal Pressure ◽  
Star Forming ◽  
Circumgalactic Medium ◽  
Cool Gas ◽  
Field Lines ◽  
Halo Masses ◽  
Collisional Ionization ◽  
The Impact

ABSTRACT We investigate the impact of cosmic rays (CRs) on the circumgalactic medium (CGM) in FIRE-2 simulations, for ultra-faint dwarf through Milky Way (MW)-mass haloes hosting star-forming (SF) galaxies. Our CR treatment includes injection by supernovae, anisotropic streaming and diffusion along magnetic field lines, and collisional and streaming losses, with constant parallel diffusivity $\kappa \sim 3\times 10^{29}\, \mathrm{cm^2\ s^{-1}}$ chosen to match γ-ray observations. With this, CRs become more important at larger halo masses and lower redshifts, and dominate the pressure in the CGM in MW-mass haloes at z ≲ 1–2. The gas in these ‘CR-dominated’ haloes differs significantly from runs without CRs: the gas is primarily cool (a few ${\sim}10^{4}\,$ K), and the cool phase is volume-filling and has a thermal pressure below that needed for virial or local thermal pressure balance. Ionization of the ‘low’ and ‘mid’ ions in this diffuse cool gas is dominated by photoionization, with O vi columns ${\gtrsim}10^{14.5}\, \mathrm{cm^{-2}}$ at distances ${\gtrsim}150\, \mathrm{kpc}$. CR and thermal gas pressure are locally anticorrelated, maintaining total pressure balance, and the CGM gas density profile is determined by the balance of CR pressure gradients and gravity. Neglecting CRs, the same haloes are primarily warm/hot ($T\gtrsim 10^{5}\,$K) with thermal pressure balancing gravity, collisional ionization dominates, O vi columns are lower and Ne viii higher, and the cool phase is confined to dense filaments in local thermal pressure equilibrium with the hot phase.

scholarly journals New Nicoletiidae (Zygentoma: Insecta) from Brazil living in fire-ant (Hymenoptera: Insecta) nests

2009 ◽  
Vol 49 (34) ◽  
pp. 467-475
Author(s):  
Luis F. Mendes ◽  
Eduardo G. P. Fox ◽  
Daniel R. Solis ◽  
Odair C. Bueno
Keyword(s):  
Rio De Janeiro ◽  
Body Shape ◽  
The Other ◽  
Fire Ant ◽  
Type Locality ◽  
Diagnostic Features ◽  
In Fire

A new myrmecophilous silverfish (Zygentoma: Nicoletiidae: Subnicoletiinae) from Rio de Janeiro, Brazil, found living in fire ant (Solenopsis saevissima, Formicidae: Myrmicinae) nests is described: Allotrichotriura saevissima gen. nov. sp. nov. is compared with the other genera and subgenera known in the subfamily. The main diagnostic features would include the combination of body shape, body and head setation, morphology of praetarsus, and number of abdominal stylets and vesicles. Although further quests were attempted at the type-locality, only the original described material, exclusively composed of females, remains known.

scholarly journals Radio observations and the mass flow rate of α Cyg (A2Ia)

1981 ◽  
Vol 59 ◽  
pp. 61-64
Author(s):  
B. Wolf ◽  
O. Stahl ◽  
W.J. Altenhoff
Keyword(s):  
Mass Loss ◽  
Mass Flow Rate ◽  
Flow Rate ◽  
Growth Analysis ◽  
Loss Rate ◽  
Mass Loss Rate ◽  
The Other ◽  
Radio Flux ◽  
Radio Observations ◽  
Lower Mass

From the free-free excess at 10μ. Barlow and Cohen (1977) (hereafter referred to as BC) derived a mass loss rate of 6.9 10-7 M⊙ yr-1 for α Cyg. They predicted a 10 GHz radio flux of 2.2 mJy. On the other hand Praderie et al. (1980) derived a considerable lower mass loss rate of 1.1 10 -8 ≤Ṁ ≤ 7 10-8 M ⊙ yr-1 from a curve of growth analysis of the envelope ultraviolet Fell-lines of α Cyg. Radio observations are desirable to make a decision about these discrepant results. Therefore we observed α Cyg at 15 GHz with the 100 m telescope of the MPIfR at Effelsberg. The observations are discussed together with recent VLA data of Abbott et al. (1980).

scholarly journals Relaxion window

2017 ◽  
Vol 32 (27) ◽  
pp. 1750142 ◽  
Author(s):  
Tatsuo Kobayashi ◽  
Osamu Seto ◽  
Takashi Shimomura ◽  
Yuko Urakawa
Keyword(s):  
Strong Correlation ◽  
Hubble Parameter ◽  
Particle Physics ◽  
Large Scale ◽  
Mass Formula ◽  
Scalar Potential ◽  
Mass Range ◽  
Lower Mass ◽  
Cosmological Constraints ◽  
Physics Model

We investigate cosmological constraints on the original relaxion scenario proposed by Graham, Kaplan and Rajendran. We first discuss the appropriate sign choice of the terms in the scalar potential, when the QCD axion is the relaxion with a relaxion–inflaton coupling proposed in the original paper. We next derive the cosmologically consistent ranges of the mass and a coupling of the relaxion for both the QCD relaxion and non-QCD relaxion. The mass range is obtained by [Formula: see text]. We also find that a strong correlation between the Hubble parameter at the relaxion stabilization and the scale [Formula: see text] of non-QCD strong dynamics, which generates the non-perturbative relaxion cosine potential. For a higher relaxion mass, a large scale [Formula: see text] becomes available. However, for its lower mass, [Formula: see text] should be small and constructing such a particle physics model is challenging.

scholarly journals Impact of correlations between $$a_{\mu }$$ and $$\alpha _\text {QED}$$ on the EW fit

2021 ◽  
Vol 81 (1) ◽  
Author(s):  
Bogdan Malaescu ◽  
Matthias Schott
Keyword(s):  
Theoretical Prediction ◽  
Experimental Measurement ◽  
Mass Range ◽  
Appropriate Use ◽  
Lower Mass ◽  
Vacuum Polarisation ◽  
Theoretical Predictions ◽  
Potential Impact ◽  
Parameter Values ◽  
The Impact

AbstractWe study the potential impact on the electroweak (EW) fits due to the tensions between the current determinations of the hadronic vacuum polarisation (HVP) contributions to the anomalous magnetic moment of the muon ($$a_{\mu }$$ a μ ), based on either phenomenological dispersion integrals using measured hadronic spectra or on Lattice QCD calculations. The impact of the current tension between the experimental measurement of $$a_{\mu }$$ a μ and the total theoretical prediction based on the phenomenological calculations of the HVP is also studied. The correlations between the uncertainties of the theoretical predictions of $$a_{\mu }$$ a μ and of the running of $$\alpha _\mathrm{QED}$$ α QED are taken into account in the studies. We conclude that the impact on the EW fit can be large in improbable scenarios involving global shifts of the full HVP contribution, while it is much smaller if the shift is restricted to a lower mass range and/or if the shift in $$\alpha _\text {QED}$$ α QED is obtained from that in $$a_{\mu }$$ a μ through appropriate use of the correlations. Indeed, the latter scenarios only imply at most a 2.6/16 increase in the $$\chi ^2/\text {n.d.f.} $$ χ 2 / n.d.f. of the EW fits and relatively small changes for the resulting fit parameter values.

scholarly journals Evolution of the Cool Gas in the Circumgalactic Medium of Massive Halos: A Keck Cosmic Web Imager Survey of Lyα Emission around QSOs at z ≈ 2

2019 ◽  
Vol 245 (2) ◽  
pp. 23 ◽  
Author(s):  
Zheng Cai ◽  
Sebastiano Cantalupo ◽  
J. Xavier Prochaska ◽  
Fabrizio Arrigoni Battaia ◽  
Joe Burchett ◽  
...  
Keyword(s):  
Circumgalactic Medium ◽  
Massive Halos ◽  
Cool Gas

scholarly journals Lower Limit for NPN's Masses

1989 ◽  
Vol 131 ◽  
pp. 454-454
Author(s):  
Amos Harpaz
Keyword(s):  
Mass Loss ◽  
Lower Limit ◽  
Planetary Nebula ◽  
Mass Range ◽  
Lower Mass ◽  
Single Star ◽  
Star Evolution ◽  
Low Mass ◽  
Red Giant

The lowest mass observed for a nucleus of a planetary nebula (NPN) is about 0.55 M⊙ (Weidemann and Koester, 1983, Schonberner, 1983). Hence, Lower mass WD's should have been produced without going through the phase of a visible PN ejection. Recently, Harpaz et al. (1987), have shown that very low mass WD's (up to 0.45 M⊙) can be formed by a single star evolution from red giant branch (RGB) stars, due to mass loss along the RGB. It turns out that WD's in mass range of 0.46–0.55 M⊙ formed by a single star evolution should be formed from the AGB, without an observable PN.

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