What powers the starburst activity of NGC 1068? Star-driven gravitational instabilities caught in the act

Romeo, Alessandro; Fathi, Kambiz

doi:10.1093/mnras/stw1147

Cited by 48 publications

(43 citation statements)

References 90 publications

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“…In conjunction with these, Goldbaum et al (2016) used the Enzo AMR hydrodynamics code (Bryan et al 2014) and argued that inflowing unstable gas could be responsible for the star formation activity in the inner parts of a galactic disk, since it may be sufficient enough to counterbalance the star formation that is suppressed by its feedback. Romeo & Fathi (2016) came to the same conclusion when they studied the starburst activity of a particular galaxy.…”

Section: Mergers and Disk Instabilitiesmentioning

confidence: 56%

Morphological evolution and galactic sizes in the L-Galaxies SA model

Irodotou

Thomas

Henriques

et al. 2019

Monthly Notices of the Royal Astronomical Society

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In this work we update the L-Galaxies semi-analytic model (SAM) to better follow the physical processes responsible for the growth of bulges via disk instabilities (leading to pseudo-bulges) and mergers (leading to classical bulges), showing the impact of these processes on the fractional breakdown of our galaxies into different morphological types, and obtaining an excellent fit to the morphology-mass relation. We find that an accurate match to the observed correlation between stellar disk scale length and mass at z ∼ 0.0 requires that the gas loses 20% of its initial specific angular momentum to the corresponding dark matter halo during the formation of the cold gas disk. With this assumption, we reproduce the observed trends between the stellar mass and specific angular momentum for both disk-and bulge-dominated galaxies, with latetype galaxies rotating faster than early-types of the same mass. We include dissipation of energy in gas-rich mergers, thus reducing the merger remnant sizes, which allows us to match the observed mass-size relation for bulge-dominated systems. Finally, we present the baryonic Tully-Fisher relation for gas-and disk-dominated galaxies, and find that our trend agrees well with the present-day observational constraints. ∆ ì J gas = δ ì J gas,cooling + δ ì J gas,SF + δ ì J gas,acc.

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Section: Mergers and Disk Instabilitiesmentioning

confidence: 56%

Morphological evolution and galactic sizes in the L-Galaxies SA model

Irodotou

Thomas

Henriques

et al. 2019

Monthly Notices of the Royal Astronomical Society

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“…itational instabilities (Romeo & Magotsi 2017). Besides, it was also shown that this feature holds good even in the inner disc of NGC 1068, a powerful nearby Seyfert+starburst galaxy (Romeo & Fathi 2016).This is possibly the reflection of the fact that in gas-rich LSB galaxies, the self-gravities of both the stellar and the gas component dominate the disc dynamics on almost an equal footing, unlike in normal spirals where the stellar component mainly contributes to the net gravitational potential. We now compare the Q min RW values for our sample LSBs with those of the combined sample of LSBs and HSBs as was obtained by Westfall et al (2014).…”

Section: Resultsmentioning

confidence: 94%

Origin of low surface brightness galaxies: a dynamical study

Garg

Banerjee

2017

Monthly Notices of the Royal Astronomical Society

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Low Surface Brighness Galaxies (LSBs), inspite of being gas rich, have low star formation rates and are, therefore, low surface brightness in nature. We calculate Q RW , the 2-component disc stability parameter as proposed by Romeo & Wiegert (2011), as a function of galactocentric radius R for a sample of five LSBs, for which mass models, as obtained from HI 21cm radio-sythesis observations and R-band photometry, were available in the literature. We find that the median value of Q min RW , the minimum of Q RW over R, lies between 2.6 and 3.1 for our sample LSBs, which is higher than the median value of 1.8 ± 0.3 for Q min RW for a sample of high surface brightness galaxies (HSBs) as obtained in earlier studies. This clearly shows that LSBs have more stable discs than HSBs, which could explain their low star formation rates and, possibly, their low surface brightness nature. Interestingly, the calculated values of Q RW decrease only slightly (median Q min RW ∼ 2.3 -3) if the discs were taken to respond to the gravitational potential of the dark matter halo only, but reduce by ∼ a factor of 2-3 (median Q min RW ∼ 0.7 -1.5) if they respond to their self-gravity alone. This implies that the dark matter halo is crucial in regulating disc stability in LSBs, which may have important implications for models of galaxy formation and evolution.

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“…Once the inner disc is formed, the dynamical assembly of the inner bar happened at a later stage from the same stellar content. The fact that the inner bar is older than the inner disc is explained by invoking some level of star formation happening in the inner disc (as well as in the outer regions) after the inner bar was already assembled (as it has actually been seen in simulations and observations ;Athanassoula 1992;Emsellem et al 2015;Romeo & Fathi 2016). This is not surprising: the shear exerted by the inner bar prevents star formation inside it, while the gas still present in the galaxy may continue forming stars outside.…”

Section: Ngc 1291: a Rather Contemporary Assembly Of All Structures Amentioning

confidence: 98%

Clocking the assembly of double-barred galaxies with the MUSE TIMER project

Lorenzo-Cáceres

Sánchez‐Blázquez

Méndez-Abreu

et al. 2019

Monthly Notices of the Royal Astronomical Society

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The formation of two stellar bars within a galaxy has proved challenging for numerical studies. It is yet not clear whether the inner bar is born via a star formation process promoted by gas inflow along the outer bar, or whether it is dynamically assembled from instabilities in a small-scale stellar disc. Observational constraints to these scenarios are scarce. We present a thorough study of the stellar content of two double-barred galaxies observed by the MUSE TIMER project, NGC 1291 and NGC 5850, combined with a two-dimensional multi-component photometric decomposition performed on the 3.6 µm images from S 4 G. Our analysis confirms the presence of σ-hollows appearing in the stellar velocity dispersion distribution at the ends of the inner bars. Both galaxies host inner discs matching in size with the inner bars, suggestive of a dynamical formation for the inner bars from small-scale discs. The analysis of the star formation histories for the structural components shaping the galaxies provides constraints on the epoch of dynamical assembly of the inner bars, which took place >6.5 Gyr ago for NGC 1291 and >4.5 Gyr ago for NGC 5850. This implies that inner bars are long-lived structures.

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What powers the starburst activity of NGC 1068? Star-driven gravitational instabilities caught in the act

Cited by 48 publications

References 90 publications

Morphological evolution and galactic sizes in the L-Galaxies SA model

Morphological evolution and galactic sizes in the L-Galaxies SA model

Origin of low surface brightness galaxies: a dynamical study

Clocking the assembly of double-barred galaxies with the MUSE TIMER project

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