Star formation and bar instability in cosmological halos

Curir, A.; Mazzei, P.; Murante, Giuseppe

doi:10.1051/0004-6361:20078285

Cited by 13 publications

(15 citation statements)

References 28 publications

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“…Moreover, low-mass galaxies are susceptible to episodic (bursty) star formation events (Bauer et al 20013), well reproduced by our simulation. As discussed in several previous papers (Mazzei & Curir 2001;Curir et al 2008, and references therein) in DM dominated disks, as in this case (Fig. 11), the patchy and lopsided morphology of the system, showing a faint inner bar and an outer semiring, arises from the disk instability induced by the halo gravitational instability itself, which is enhanced by the interaction.…”

Section: Matching the Ngc 3447a/ngc 3447 System Propertiessupporting

confidence: 73%

Galaxy evolution in groups

Mazzei

Marino

Rampazzo

et al. 2018

A&A

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Context. Local Group Analogs are galaxy associations dominated by few bright Spirals reminiscent of the Local Group. The NGC 3447/NGC 3447A system is a member of the LGG 225 group, a nearby Local Group Analog. This system is considered a physical pair composed of an intermediate luminosity late type spiral, NGC 3447 itself, and an irregular companion, NGC 3447A, linked by a faint, short filament of matter. A ring-like structure in the NGC 3447 outskirts has been emphasised by GALEX observations. Aims. This work aims to contribute to the study of galaxy evolution in low density environments, favourable habitat to highly effective encounters, shedding light on the evolution of this system. Methods. We performed a multi-λ analysis of the surface photometry of this system to derive its spectral energy distribution and structural properties using UV, Swift-UVOT, and optical, SDSS images complemented with available far-IR observations. We also characterised the velocity field of the pair using 2D Hα kinematical observations of the system obtained with PUMA@2.2mSPM. All these data are used to constrain smooth particle hydrodynamic simulations with chemo-photometric implementation to shed light on the evolution of this system. Results. The luminosity profiles, from UV to optical wavelengths, are all consistent with the presence of a disc extending and including NGC 3447A. The overall velocity field does not emphasise any significant rotation pattern, rather a small velocity gradient between NGC 3447 and NGC 3447A. Our simulation, detached from a large grid explored to best-fit the global properties of the system, suggests that this arises from an encounter between two halos of equal mass. Conclusions. NGC 3447 and NGC 3447A belong to the same halo, NGC 3447A being a substructure of the same disk including NGC 3447. The halo gravitational instability, enhanced by the encounter, fuels a long lived instability in this dark matter dominated disk, driving the observed morphology. The NGC 3447/NGC 3447A system may warn about a new class of "false pairs" and the potential danger of a misunderstanding of such objects in pair surveys that could produce a severe underestimate of the total mass of the system.

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Section: Matching the Ngc 3447a/ngc 3447 System Propertiessupporting

confidence: 73%

Galaxy evolution in groups

Mazzei

Marino

Rampazzo

et al. 2018

A&A

Self Cite

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“…Clearly the theoretical ingredients of the Bekki (2007) Lisker et al 2006a), this may be accomplished by either an enhanced disk/spheroid growth mode and/or suppression of the nuclear mass accumulation mechanism, e.g. via advective angular momentum transport, bar instabilities, and/or the presence of a central black hole (Curir et al 2008(Curir et al , 2010Foyle et al 2010;Goz et al 2015;James & Percival 2018).…”

Section: Model Predictionsmentioning

confidence: 99%

The Next Generation Fornax Survey (NGFS). IV. Mass and Age Bimodality of Nuclear Clusters in the Fornax Core Region

Órdenes-Briceño

Puzia

Eigenthaler

et al. 2018

ApJ

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We present the analysis of 61 nucleated dwarf galaxies in the central regions ( R vir /4) of the Fornax galaxy cluster. The galaxies and their nuclei are studied as part of the Next Generation Fornax Survey (NGFS) using optical imaging obtained with the Dark Energy Camera (DECam) mounted at Blanco/CTIO and near-infrared data obtained with VIRCam at VISTA/ESO. We decompose the nucleated dwarfs in nucleus and spheroid, after subtracting the surface brightness profile of the spheroid component and studying the nucleus using PSF photometry. In general, nuclei are consistent with colors of confirmed metal-poor globular clusters, but with significantly smaller dispersion than other confirmed compact stellar systems in Fornax. We find a bimodal nucleus mass distribution with peaks located at log(M * /M ) 5.4 and ∼ 6.3. These two nucleus sub-populations have different stellar population properties, the more massive nuclei are older than ∼ 2 Gyr and have metal-poor stellar populations (Z ≤ 0.02 Z ), while the less massive nuclei are younger than ∼ 2 Gyr with metallicities in the range 0.02 < Z/Z ≤ 1. We find that the nucleus mass (M nuc ) vs. galaxy mass (M gal ) relation becomes shallower for less massive galaxies starting around 10 8 M and the mass ratio η n = M nuc /M gal shows a clear anti-correlation with M gal for the lowest masses, reaching 10%. We test current theoretical models of nuclear cluster formation and find that they cannot fully reproduce the observed trends. A likely mixture of in-situ star formation and star-cluster mergers seem to be acting during nucleus growth over cosmic time.

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“…Curir et al (2006) built zoomed Initial Conditions (hereafter ICs) of DM halos in cosmological volumes, let them evolve with an N-body code and placed model disks inside the halos that were present at some specified redshift. That paper considered purely stellar disks, while stellar+gas disks were presented in Curir et al (2007) and the effect of star formation was considered in Curir et al (2008). In these works it was shown that halo triaxiality, at the level commonly found in simulated DM halos, triggers the formation of bars.…”

Section: Introductionmentioning

confidence: 99%

Properties of barred spiral discs in hydrodynamical cosmological simulations

Goz¹,

Monaco

Murante

et al. 2014

Monthly Notices of the Royal Astronomical Society

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We present a quantification of the properties of bars in two N-body+SPH cosmological simulations of spiral galaxies, named GA and AqC. The initial conditions were obtained using the zoom-in technique and represent two dark matter (DM) halos of 2−3×10 12 M ⊙ , available at two different resolutions. The resulting galaxies are presented in the companion paper of Murante et al. (2014). We find that the GA galaxy has a bar of length 8.8 kpc, present at the two resolution levels even though with a slightly different strength. Classical bar signatures (e.g. pattern of streaming motions, high m = 2 Fourier mode with roughly constant phase) are consistently found at both resolutions. Though a close encounter with a merging satellite at z ∼ 0.6 (mass ratio 1 : 50) causes a strong, transient spiral pattern and some heating of the disk, we find that bar instability is due to secular process, caused by a low Toomre parameter Q 1 due to accumulation of mass in the disk. The AqC galaxy has a slightly different history: it suffers a similar tidal disturbance due to a merging satellite at z ∼ 0.5 but with a mass ratio of 1 : 32, that triggers a bar in the high-resolution simulation, while at low resolution the merging is found to take place at a later time, so that both secular evolution and merging are plausible triggers for bar instability.

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Star formation and bar instability in cosmological halos

Cited by 13 publications

References 28 publications

Galaxy evolution in groups

Galaxy evolution in groups

The Next Generation Fornax Survey (NGFS). IV. Mass and Age Bimodality of Nuclear Clusters in the Fornax Core Region

Properties of barred spiral discs in hydrodynamical cosmological simulations

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