Signatures of Cool Gas Fueling a Star-Forming Galaxy at Redshift 2.3

Galaxies are thought to be fed by the continuous accretion of intergalactic gas, but direct observational evidence has been elusive. The accreted gas is expected to orbit about the galaxy’s halo, delivering not just fuel for star formation but also angular momentum to the galaxy, leading to distinct kinematic signatures. We report observations showing these distinct signatures near a typical distant star-forming galaxy, where the gas is detected using a background quasar passing 26 kiloparsecs from the host. Our observations indicate that gas accretion plays a major role in galaxy growth because the estimated accretion rate is comparable to the star-formation rate.

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Tracing black hole and galaxy co-evolution in the Romulus simulations

Monthly Notices of the Royal Astronomical Society ◽

10.1093/mnras/stz2161 ◽

2019 ◽

Vol 489 (1) ◽

pp. 802-819 ◽

Cited By ~ 7

Author(s):

Angelo Ricarte ◽

Michael Tremmel ◽

Priyamvada Natarajan ◽

Thomas Quinn

Keyword(s):

Black Hole ◽

Star Formation ◽

Star Formation Rate ◽

Accretion Rate ◽

Formation Rate ◽

Star Forming ◽

Black Hole Accretion ◽

Black Hole Growth ◽

Hole Growth ◽

Hole Accretion

ABSTRACT We study the link between supermassive black hole growth and the stellar mass assembly of their host galaxies in the state-of-the-art Romulus suite of simulations. The cosmological simulations Romulus25 and RomulusC employ innovative recipes for the seeding, accretion, and dynamics of black holes in the field and cluster environments, respectively. We find that the black hole accretion rate traces the star formation rate among star-forming galaxies. This result holds for stellar masses between 108 and 1012 solar masses, with a very weak dependence on host halo mass or redshift. The inferred relation between accretion rate and star formation rate does not appear to depend on environment, as no difference is seen in the cluster/proto-cluster volume compared to the field. A model including the star formation rate, the black hole-to-stellar mass ratio, and the cold gas fraction can explain about 70 per cent of all variations in the black hole accretion rate among star-forming galaxies. Finally, bearing in mind the limited volume and resolution of these cosmological simulations, we find no evidence for a connection between black hole growth and galaxy mergers, on any time-scale and at any redshift. Black holes and their galaxies assemble in tandem in these simulations, regardless of the larger scale intergalactic environment, suggesting that black hole growth simply follows star formation on galactic scales.

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A correlation between star formation rate and average black hole accretion rate in star forming galaxies

Proceedings of the International Astronomical Union ◽

10.1017/s1743921314004128 ◽

2013 ◽

Vol 9 (S304) ◽

pp. 302-306

Author(s):

Chien-Ting J. Chen ◽

Ryan C. Hickox

Keyword(s):

Star Formation ◽

Galaxy Evolution ◽

Star Formation Rate ◽

Accretion Rate ◽

Formation Rate ◽

Far Infrared ◽

Host Galaxies ◽

Star Forming ◽

Black Hole Accretion ◽

Strong Linear Correlation

AbstractWe present the results of recent studies on the co-evolution of galaxies and the supermassive black holes (SMBHs) using Herschel far-infrared and Chandra X-ray observations in the Boötes survey region. For a sample of star-forming (SF) galaxies, we find a strong correlation between galactic star formation rate and the average SMBH accretion rate in SF galaxies. Recent studies have shown that star formation and AGN accretion are only weakly correlated for individual AGN, but this may be due to the short variability timescale of AGN relative to star formation. Averaging over the full AGN population yields a strong linear correlation between accretion and star formation, consistent with a simple picture in which the growth of SMBHs and their host galaxies are closely linked over galaxy evolution time scales.

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A contribution of star-forming clumps and accreting satellites to the mass assembly of z ∼ 2 galaxies

Monthly Notices of the Royal Astronomical Society ◽

10.1093/mnras/stz2099 ◽

2019 ◽

Vol 489 (2) ◽

pp. 2792-2818 ◽

Cited By ~ 11

Author(s):

A Zanella ◽

E Le Floc’h ◽

C M Harrison ◽

E Daddi ◽

E Bernhard ◽

...

Keyword(s):

Star Formation ◽

Star Formation Rate ◽

Formation Rate ◽

Stellar Mass ◽

Mass Ratio ◽

Star Forming ◽

Spatially Resolved ◽

The Galaxy ◽

Mass Assembly

ABSTRACT We investigate the contribution of clumps and satellites to the galaxy mass assembly. We analysed spatially resolved HubbleSpace Telescope observations (imaging and slitless spectroscopy) of 53 star-forming galaxies at z ∼ 1–3. We created continuum and emission line maps and pinpointed residual ‘blobs’ detected after subtracting the galaxy disc. Those were separated into compact (unresolved) and extended (resolved) components. Extended components have sizes ∼2 kpc and comparable stellar mass and age as the galaxy discs, whereas the compact components are 1.5 dex less massive and 0.4 dex younger than the discs. Furthermore, the extended blobs are typically found at larger distances from the galaxy barycentre than the compact ones. Prompted by these observations and by the comparison with simulations, we suggest that compact blobs are in situ formed clumps, whereas the extended ones are accreting satellites. Clumps and satellites enclose, respectively, ∼20 per cent and ≲80 per cent of the galaxy stellar mass, ∼30 per cent and ∼20 per cent of its star formation rate. Considering the compact blobs, we statistically estimated that massive clumps (M⋆ ≳ 109 M⊙) have lifetimes of ∼650 Myr, and the less massive ones (108 < M⋆ < 109 M⊙) of ∼145 Myr. This supports simulations predicting long-lived clumps (lifetime ≳ 100 Myr). Finally, ≲30 per cent (13 per cent) of our sample galaxies are undergoing single (multiple) merger(s), they have a projected separation ≲10 kpc, and the typical mass ratio of our satellites is 1:5 (but ranges between 1:10 and 1:1), in agreement with literature results for close pair galaxies.

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Star Formation Thresholds: The View from Inside the Galaxy

Proceedings of the International Astronomical Union ◽

10.1017/s1743921316007481 ◽

2015 ◽

Vol 11 (S315) ◽

pp. 183-190

Author(s):

James Di Francesco

Keyword(s):

Star Formation ◽

Surface Density ◽

Column Density ◽

Star Formation Rate ◽

Formation Rate ◽

Star Forming ◽

Gould Belt ◽

The Galaxy ◽

Dynamical Properties ◽

The Relationship

AbstractWe explore the relationship between the total gas surface density and star formation rate surface density, a.k.a., the “Kennicutt-Schmidt relation,” in a Galactic context. Specifically, we probe the origins of thresholds in the behaviour of the K-S relation at 10 M⊙ pc−2 and 100-200 M⊙ pc−2 using images from the Herschel Hi-GAL and Gould Belt surveys. In both cases, pervasive filamentary structures are seen, possibly due to turbulent motions. The Hi-GAL image supports the view that at ~10 M⊙ pc−2 gas becomes molecular, leading to the formation of clouds that harbour star formation. The GBS images suggest the 100-200 M⊙ pc−2 threshold originates from the nature of filaments being stable until a critical column density of ~160 M⊙ pc−2 is reached. Therefore, the transition between non-star-forming and star-forming gas in clouds (and galaxies) may be set universally by the dynamical properties of filaments.

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Cosmic rays across the star-forming galaxy sequence. II: Stability limits and the onset of cosmic ray-driven outflows

Monthly Notices of the Royal Astronomical Society ◽

10.1093/mnras/stab502 ◽

2021 ◽

Author(s):

Roland M Crocker ◽

Mark R Krumholz ◽

Todd A Thompson

Keyword(s):

Star Formation ◽

Cosmic Rays ◽

Surface Density ◽

Star Formation Rate ◽

Formation Rate ◽

Cosmic Ray ◽

Star Forming ◽

Rate Versus ◽

The Galaxy ◽

Plausible Mechanism

Abstract Cosmic rays (CRs) are a plausible mechanism for launching winds of cool material from the discs of star-forming galaxies. However, there is no consensus on what types of galaxies likely host CR-driven winds, or what role these winds might play in regulating galaxies’ star formation rates. Using a detailed treatment of the transport and losses of hadronic CRs developed in the previous paper in this series, here we develop a semi-analytic model that allows us to assess the viability of using CRs to launch cool winds from galactic discs. In particular, we determine the critical CR fluxes – and corresponding star formation rate surface densities – above which hydrostatic equilibrium within a given galaxy is precluded because CRs drive the gas off in a wind or otherwise render it unstable. Our model demonstrates that catastrophic, CR-driven wind loss is a possibility at galactic mean surface densities below $\, {\lesssim}\, 10^2 \ M_{\odot }$ pc−2. In this regime – encompassing the Galaxy and local dwarfs – the locus of the CR stability curve patrols the high side of the observed distribution of galaxies in the Kennicutt-Schmidt parameter space of star formation rate versus gas surface density. However, hadronic losses render CRs unable to drive global winds in galaxies with surface densities above the ∼102 − 103M⊙ pc−2 transition region. Our results show that quiescent, low surface density galaxies like the Milky Way are poised on the cusp of instability, such that small changes to ISM parameters can lead to the launching of CR-driven outflows, and we suggest that, as a result, CR feedback sets an ultimate limit to the star formation efficiency of most modern galaxies.

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Rejuvenation triggers nuclear activity in nearby galaxies

10.21203/rs.3.rs-464309/v1 ◽

2021 ◽

Author(s):

Ignacio Martin Navarro ◽

Francesco Shankar ◽

Mar Mezcua

Keyword(s):

Dark Matter ◽

Star Formation ◽

Star Formation Rate ◽

Formation Rate ◽

Sloan Digital Sky Survey ◽

Dark Matter Halo ◽

Sudden Increase ◽

Star Forming ◽

Normal Galaxies ◽

Gas Accretion

Abstract Galaxies, forming and evolving within their host dark matter haloes, are the end-product of a balance between gas cooling, star formation and feedback. Energy/Momentum feedback, in particular from active galactic nuclei (AGN), is believed to play a crucial role in the evolution of galaxies by gradually quenching their star formation. In the local Universe many galaxies with an AGN are indeed observed to reside in the so-called green valley, usually interpreted as a transition phase from a blue star formation epoch to a red quenched state. We use data from the Sloan Digital Sky Survey to show that such an interpretation requires substantial revision. Optically-selected nearby AGN galaxies follow exponentially declining star formation histories, as normal galaxies of similar stellar and dark matter halo mass, reaching in the recent past (~0.1 Gyr ago) star formation rate levels consistent with a quiescent population. However, we find that local AGN galaxies have experienced a sudden increase in their star formation rate, unfolding on timescales similar to those typical of AGN activity, suggesting that both star formation and AGN activity were triggered simultaneously. We find that this quenching process followed by an enhancement in the star formation rate is common to AGN galaxies and more pronounced in early type galaxies. Our results demonstrate that local AGN galaxies are not a transition type between star-forming and quiescent galaxies as previously postulated, but simply galaxies experiencing a recent gas accretion episode.

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Impact of relativistic jets on the star formation rate: A turbulence-regulated framework

Monthly Notices of the Royal Astronomical Society ◽

10.1093/mnras/stab2822 ◽

2021 ◽

Author(s):

Ankush Mandal ◽

Dipanjan Mukherjee ◽

Christoph Federrath ◽

Nicole P H Nesvadba ◽

Geoffrey V Bicknell ◽

...

Keyword(s):

Star Formation ◽

Velocity Dispersion ◽

Star Formation Rate ◽

Formation Rate ◽

Star Forming ◽

Radio Jets ◽

Star Formation Activity ◽

The Galaxy ◽

Individual Star ◽

The Impact

Abstract We apply a turbulence-regulated model of star formation to calculate the star formation rate (SFR) of dense star-forming clouds in simulations of jet-ISM interactions. The method isolates individual clumps and accounts for the impact of virial parameter and Mach number of the clumps on the star formation activity. This improves upon other estimates of the SFR in simulations of jet–ISM interactions, which are often solely based on local gas density, neglecting the impact of turbulence. We apply this framework to the results of a suite of jet-ISM interaction simulations to study how the jet regulates the SFR both globally and on the scale of individual star-forming clouds. We find that the jet strongly affects the multi-phase ISM in the galaxy, inducing turbulence and increasing the velocity dispersion within the clouds. This causes a global reduction in the SFR compared to a simulation without a jet. The shocks driven into clouds by the jet also compress the gas to higher densities, resulting in local enhancements of the SFR. However, the velocity dispersion in such clouds is also comparably high, which results in a lower SFR than would be observed in galaxies with similar gas mass surface densities and without powerful radio jets. We thus show that both local negative and positive jet feedback can occur in a single system during a single jet event, and that the star-formation rate in the ISM varies in a complicated manner that depends on the strength of the jet-ISM coupling and the jet break-out time-scale.

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Properties of galaxies with an offset between the position angles of the major kinematic and photometric axes

Astronomy and Astrophysics ◽

10.1051/0004-6361/201936357 ◽

2020 ◽

Vol 634 ◽

pp. A26 ◽

Cited By ~ 2

Author(s):

L. S. Pilyugin ◽

E. K. Grebel ◽

I. A. Zinchenko ◽

J. M. Vílchez ◽

F. Sakhibov ◽

...

Keyword(s):

Star Formation ◽

Surface Brightness ◽

Star Formation Rate ◽

Formation Rate ◽

Velocity Fields ◽

Oxygen Abundance ◽

Star Forming ◽

Measured Position ◽

Central Oxygen ◽

Straight Lines

We derive the photometric, kinematic, and abundance characteristics of 18 star-forming MaNGA galaxies with fairly regular velocity fields and surface brightness distributions and with a large offset between the measured position angles of the major kinematic and photometric axes, ΔPA ≳ 20°. The aim is to examine if there is any other distinctive characteristic common to these galaxies. We found morphological signs of interaction in some (in 11 out of 18) but not in all galaxies. The observed velocity fields show a large variety; the maps of the isovelocities vary from an hourglass-like appearance to a set of straight lines. The position angles of the major kinematic axes of the stellar and gas rotations are close to each other. The values of the central oxygen abundance, radial abundance gradient, and star formation rate are distributed within the intervals defined by galaxies with small (no) ΔPA of similar mass. Thus, we do not find any specific characteristic common to all galaxies with large ΔPA. Instead, the properties of these galaxies are similar to those of galaxies with small (no) ΔPA. This suggests that either the reason responsible for the large ΔPA does not influence other characteristics or the galaxies with large ΔPA do not share a common origin, they can, instead, originate through different channels.

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Morphometry as a probe of the evolution of jellyfish galaxies: evidence of broadening in the surface brightness profiles of ram-pressure stripping candidates in the multicluster system A901/A902

Monthly Notices of the Royal Astronomical Society ◽

10.1093/mnras/staa3226 ◽

2020 ◽

Vol 500 (1) ◽

pp. 40-53

Author(s):

Fernanda Roman-Oliveira ◽

Ana L Chies-Santos ◽

Fabricio Ferrari ◽

Geferson Lucatelli ◽

Bruno Rodríguez Del Pino

Keyword(s):

Star Formation ◽

Surface Brightness ◽

Quantitative Measurement ◽

Star Formation Rate ◽

Hubble Space Telescope ◽

Formation Rate ◽

Structural Evolution ◽

Star Forming ◽

Irregular Structures ◽

Ram Pressure

ABSTRACT We explore the morphometric properties of a group of 73 ram-pressure stripping candidates in the A901/A902 multicluster system, at z∼ 0.165, to characterize the morphologies and structural evolution of jellyfish galaxies. By employing a quantitative measurement of morphometric indicators with the algorithm morfometryka on Hubble Space Telescope (F606W) images of the galaxies, we present a novel morphology-based method for determining trail vectors. We study the surface brightness profiles and curvature of the candidates and compare the results obtained with two analysis packages, morfometryka and iraf/ellipse on retrieving information of the irregular structures present in the galaxies. Our morphometric analysis shows that the ram-pressure stripping candidates have peculiar concave regions in their surface brightness profiles. Therefore, these profiles are less concentrated (lower Sérsic indices) than other star-forming galaxies that do not show morphological features of ram-pressure stripping. In combination with morphometric trail vectors, this feature could both help identify galaxies undergoing ram-pressure stripping and reveal spatial variations in the star formation rate.

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