Star formation and AGN activity in interacting galaxies: a near-UV perspective

Scott, Caroline; Kaviraj, Sugata

doi:10.1093/mnras/stt2014

Cited by 32 publications

(35 citation statements)

References 69 publications

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“…The first point is qualitatively in line with observations (Woods et al 2006;Ellison et al 2008;Lambas et al 2012;Ellison et al 2013;Patton et al 2013;Scott & Kaviraj 2014) and predictions by earlier simulations (Mihos & Hernquist 1996;Di Matteo et al 2007, 2008Renaud & Gieles 2013;Hayward et al 2014;Moreno et al 2015). Regarding the second and third points: one might naïvely expect intense star-forming episodes to either consume the cold-dense gas content (and deplete the cool gas as this transforms into cold-dense gas), or expel this gas via feedback produced by new stars.…”

Section: Discussionsupporting

confidence: 87%

Interacting galaxies on FIRE-2: the connection between enhanced star formation and interstellar gas content

Moreno

Torrey

Ellison

et al. 2019

Monthly Notices of the Royal Astronomical Society

125

143

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We present a comprehensive suite of high-resolution (parsec-scale), idealised (noncosmological) galaxy merger simulations (24 runs, stellar mass ratio ∼2.5:1) to investigate the connection between interaction-induced star formation and the evolution of the interstellar medium (ISM) in various temperature-density regimes. We use the GIZMO code and the second version of the "Feedback in Realistic Environments" model (FIRE-2), which captures the multi-phase structure of the ISM. Our simulations are designed to represent galaxy mergers in the local Universe. In this work, we focus on the 'galaxy-pair period' between first and second pericentric passage. We split the ISM into four regimes: hot, warm, cool and cold-dense, motivated by the hot, ionised, atomic and molecular gas phases observed in real galaxies. We find that, on average, interactions enhance the star formation rate of the pair (∼30%, merger-suite sample average) and elevate their cold-dense gas content (∼18%). This is accompanied by a decrease in warm gas (∼11%), a negligible change in cool gas (∼4% increase), and a substantial increase in hot gas (∼400%). The amount of cold-dense gas with densities above 1000 cm −3 (the cold ultra-dense regime) is elevated significantly (∼240%), but only accounts for ∼0.15% (on average) of the cold-dense gas budget.

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Section: Discussionsupporting

confidence: 87%

Interacting galaxies on FIRE-2: the connection between enhanced star formation and interstellar gas content

Moreno

Torrey

Ellison

et al. 2019

Monthly Notices of the Royal Astronomical Society

125

143

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“…Many observations have reported that the SF rate (SFR) in close galaxy pairs is higher than isolated galaxies (Barton et al 2000;Lambas et al 2003Lambas et al , 2012Alonso et al 2004;Nikolic et al 2004;Woods et al 2006Woods et al , 2010Woods & Geller 2007;Ellison et al 2008Ellison et al , 2013Li et al 2008;Darg et al 2010b;Patton et al 2011Patton et al , 2013Wong et al 2011;Scott & Kaviraj 2014). The theoretical expectation agrees well with the observational results (Cox et al 2006(Cox et al , 2008Di Matteo et al 2007Patton et al 2013;Moreno et al 2015).…”

supporting

confidence: 71%

Living with Neighbors. I. Observational Clues to Hydrodynamic Impact of Neighboring Galaxies on Star Formation

Moon

Yoon³

2019

ApJ

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Galaxies in pairs show enhanced star formation (SF) compared to their counterparts in isolation, which is often explained by the tidal effect of neighboring galaxies. Recent observations, however, reported that galaxies paired with early-type neighbors do not undergo the SF enhancement. Here we revisit the influence of neighbors using a large sample of paired galaxies from the Sloan Digital Sky Survey and a carefully constructed control sample of isolated counterparts. We find that star-forming neighbors enhance SF, and even more so for more star-forming (and closer) neighbors, which can be attributed to collisions of interstellar medium (ISM) leading to SF. We further find that, contrary to the anticipated tidal effect, quiescent neighbors quench SF, and even more so for more quiescent (and closer) neighbors. This seems to be due to removal of gas reservoirs via ram pressure stripping and gas accretion cutoff by hot gas halos of quiescent neighbors, on top of their paucity of ISM to collide to form stars. Our findings, especially the intimate connection of SF to the status and strength of neighbors' SF, imply that the hydrodynamic mechanisms, along with the tidal effect, play a crucial role during the early phase of galactic interactions.

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“…Interestingly, several authors have found a connection between AGN activity and interacting galaxies (Scott &Kaviraj 2014 andScoville 2003). In view of our results, we can speculate that the galaxy interactions in the group NGC 6845 can be activating the central black holes of these galaxies, however, integral field spectroscopic observations are necessary to study in details these galaxies.…”

Section: The Evolutionary Stage Of Ngc 6845supporting

confidence: 55%

NGC 6845: metallicity gradients and star formation in a complex compact group

Olave-Rojas

Torres-Flores

Carrasco

et al. 2015

Mon. Not. R. Astron. Soc.

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We have obtained Gemini/GMOS spectra of 28 regions located across the interacting group NGC 6845, spanning from the inner regions of the four major galaxies (NGC 6845A, B, C, D) to the tidal tails of NGC 6845A. All regions in the tails are starforming objects with ages younger than 10 Myr. We derived the gas-phase metallicity gradients across NGC 6845A and its two tails and we find that these are shallower than those for isolated galaxies. NGC 6845A has a gas-phase oxygen central metallicity of 12+log(O/H)∼8.5 and a flat gas-phase metallicity gradient (β=0.002±0.004 dex kpc −1 ) out to ∼4 × R 25 (to the end of the longest tidal tail). Considering the mass-metallicity relation, the central region of NGC 6845A displays a lower oxygen abundance than the expected for its mass. Taking into account this fact and considering the flat oxygen distribution measured along the eastern tidal tail, we suggest that an interaction event has produced a dilution in the central metallicity of this galaxy and the observed flattening in its metal distribution. We found that the star formation process along the eastern tidal structure has not been efficient enough to increase the oxygen abundances in this place, suggesting that this structure was formed from enriched material.

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Star formation and AGN activity in interacting galaxies: a near-UV perspective

Cited by 32 publications

References 69 publications

Interacting galaxies on FIRE-2: the connection between enhanced star formation and interstellar gas content

Interacting galaxies on FIRE-2: the connection between enhanced star formation and interstellar gas content

Living with Neighbors. I. Observational Clues to Hydrodynamic Impact of Neighboring Galaxies on Star Formation

NGC 6845: metallicity gradients and star formation in a complex compact group

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