Ecological Restoration

Glazebrook, Trish

doi:10.1002/9781444367072.wbiee338

Cited by 23 publications

(33 citation statements)

References 3 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The identification of clumpy galaxies in the dominant population of irregular galaxies at high redshift dates back to the first deep Hubble Space Telescope (HST) images (e.g., Williams et al 1996). Subsequent studies at z ∼ 1 − 3 revealed that clumpy galaxies are more numerous than in the local Universe (e.g., Abraham et al 1996;van den Bergh et al 1996;Giavalisco et al 1996;Elmegreen et al 2004;Elmegreen & Elmegreen 2006;Elmegreen et al 2007Elmegreen et al , 2008Elmegreen et al , 2009Elmegreen et al , 2013Kubo et al 2013Kubo et al , 2016Glazebrook 2013;Tadaki et al 2014;Murata et al 2014;Guo et al 2015;Garland et al 2015;Bournaud 2016). The fraction of clumpy galaxies was studied from z=0 up to the most distant galaxies identified today at z∼10 (Ravindranath et al 2006;Guo et al 2012Guo et al , 2015Shibuya et al 2016).…”

Section: Introductionmentioning

confidence: 99%

The VIMOS Ultra-Deep Survey: A major merger origin for the high fraction of galaxies at 2 < z < 6 with two bright clumps

Ribeiro

Fèvre

Cassata

et al. 2017

A&A

View full text Add to dashboard Cite

The properties of stellar clumps in star-forming galaxies and their evolution over the redshift range 2 z 6 are presented and discussed in the context of the build-up of massive galaxies at early cosmic times. We focused on galaxies with spectroscopic redshifts from the VIMOS Ultra Deep Survey (VUDS) and stellar masses log 10 (M /M ) > −0.204 × (z − 4.5) + 9.35. We analyzed HST-ACS images to identify clumps within a 20 kpc radius using a method taking into account differential surface brightness dimming and luminosity evolution with redshift. We find that the population of galaxies with more than one clump is dominated by galaxies with two clumps, representing ∼21-25% of the population, while the fraction of galaxies with three, or four and more, clumps is 8-11 and 7-9%, respectively. The fraction of clumpy galaxies is in the range ∼ 35 − 55% over 2 < z < 6, increasing at higher redshifts, indicating that the fraction of irregular galaxies remains high up to the highest redshifts. The large and bright clumps (M star ∼ 10 9 up to ∼ 10 10 M ) are found to reside predominantly in galaxies with two clumps. Smaller and lower luminosity clumps (M star < 10 9 M ) are found in galaxies with three clumps or more. We interpret these results as evidence for two different modes of clump formation working in parallel. The small low luminosity clumps are likely the result of disk fragmentation, with violent disk instabilities (VDI) forming several long-lived clumps in-situ. as suggested from simulations. A fraction of these clumps is also likely coming from minor mergers as confirmed from spectroscopy in several cases. The clumps in the dominating population of galaxies with two clumps are significantly more massive and have properties akin to those in galaxy pairs undergoing massive merging observed at similar redshifts; they appear as more massive than the most massive clumps observed in numerical simulations of disks with VDI. We infer from these properties that the bright and large clumps are most likely the result of major mergers bringing-in ex-situ matter onto a galaxy, and we derive a high major merger fraction of ∼20%. The diversity of clump properties therefore suggests that the assembly of star-forming galaxies at z∼ 2 − 6 proceeds from several different dissipative processes including an important contribution from major and minor mergers.

show abstract

Section: Introductionmentioning

confidence: 99%

The VIMOS Ultra-Deep Survey: A major merger origin for the high fraction of galaxies at 2 < z < 6 with two bright clumps

Ribeiro

Fèvre

Cassata

et al. 2017

A&A

View full text Add to dashboard Cite

show abstract

“…Locally, we can use present-day stellar kinematics to infer the past evolution of our Milky Way (MW) through Galactic Archeology, (e.g., Belokurov et al 2018;Frankel et al 2018Frankel et al , 2019. At higher redshift, large galaxy surveys are yielding results on the evolution of populations of galaxies over time (e.g., see the review by Glazebrook 2013). If the MW (and other local galaxies) kinematically evolve in a fashion similar to high z galaxies, then in principle results from these two epochs should be able to be explained within the same theoretical framework.…”

Section: Introductionmentioning

confidence: 99%

“…When combined with the Schmidt-Kennicutt star formation relation, the gas surface density is also tied to the star formation rate, (e.g., Green et al 2014;Leroy et al 2016;Semenov et al 2016). If the disk is marginally stable, and it is assumed that gas (rather than stars) is the predominant component of the gravitational potential, the higher gas surface densities and gas fractions at higher redshift (e.g., Genzel et al 2006;Daddi et al 2010;Jones et al 2010;Genzel et al 2011;Tacconi et al 2013;Glazebrook 2013;Popping et al 2015;Krumholz & Burkhart 2016;Stott et al 2016;Wiklind et al 2019) should naturally lead to higher gas velocity dispersion. For more local galaxies, feedback from star-formation may also play a critical role in setting a dynamical "floor" for the star-forming gas (e.g., Agertz et al 2009;Faucher-Giguère et al 2013;Stilp et al 2013;Semenov et al 2018;Orr et al 2019a,b).…”

Section: Introductionmentioning

confidence: 99%

Inside Out and Upside-Down: The Roles of Gas Cooling and Dynamical Heating in Shaping the Stellar Age-Velocity Relation

Bird,

Loebman,

Weinberg

et al. 2020

Preprint

View full text Add to dashboard Cite

Kinematic studies of disk galaxies, using individual stars in the Milky Way or statistical studies of global disk kinematics over time, provide insight into how disks form and evolve. We use a high-resolution, cosmological zoom-simulation of a Milky Way-mass disk galaxy (h277) to tie together local disk kinematics and the evolution of the disk over time. The present-day stellar age-velocity relationship (AVR) of h277 is nearly identical to that of the analogous solar-neighborhood measurement in the Milky Way. A crucial element of this success is the simulation's dynamically cold multi-phase ISM, which allows young stars to form with a low velocity dispersion (σ birth ∼ 6 − 8 km s −1 ) at late times. Older stars are born kinematically hotter (i.e., the disk settles over time in an "upside-down" formation scenario), and are subsequently heated after birth. The disk also grows "inside-out", and many of the older stars in the solar neighborhood at z = 0 are present because of radial mixing. We demonstrate that the evolution of σ birth in h277 can be explained by the same model used to describe the general decrease in velocity dispersion observed in disk galaxies from z ∼ 2 − 3 to the present-day, in which the disk evolves in quasi-stable equilibrium and the ISM velocity dispersion decreases over time due to a decreasing gas fraction. Thus, our results tie together local observations of the Milky Way's AVR with observed kinematics of high z disk galaxies.

show abstract

“…The kinematic characterization of different galaxy populations is a key observational input in distinguishing between different evolutionary paradigms, such as the "major merger" (Tacconi et al 2006(Tacconi et al , 2008Kartaltepe et al 2012) and the "steady cold gas accretion" (Kereš et al 2005;Ocvirk et al 2008;Dekel et al 2009a;Ceverino et al 2010) scenarios, since it allows one to determine the fraction of rotating disks to mergers at different cosmic epochs (see e.g., Genzel et al 2001;Tacconi et al 2008;Dekel et al 2009b;Förster Schreiber et al 2009;Bournaud et al 2011;Epinat 2011;Glazebrook 2013;Bellocchi et al 2016). Kinematics is also important in the study of physical processes that govern the formation and evolution of the galaxies, providing a powerful diagnostic to infer the main source of dynamic support (Puech et al 2007;Epinat et al 2009;Cappellari et al 2013;Zhu et al 2018), to distinguish between relaxed virialized systems and merger events (Flores et al 2006;Shapiro et al 2008;Bellocchi et al 2012Bellocchi et al , 2016Barrera-Ballesteros et al 2015), to infer fundamental galaxy quantities like the dynamical mass (Colina et al 2005;Bellocchi et al 2013;Aquino-Ortíz et al 2018), and also to detect and characterize radial motions associated with feedback mechanisms, like massive gas outflows (Shapiro et al 2009;Rupke & Veilleux 2013;López-Cobá et al 2017a,b;Maiolino et al 2017).…”

Section: Introductionmentioning

confidence: 99%

Uncertainties in gas kinematics arising from stellar continuum modeling in integral field spectroscopy data: the case of NGC 2906 observed with VLT/MUSE

Bellocchi

Ascasíbar

Galbany

et al. 2019

A&A

View full text Add to dashboard Cite

Context. Integral field spectroscopy (IFS) provides detailed information about galaxy kinematics at high spatial and spectral resolution, and the disentanglement of the gaseous and stellar components is a key step in the analysis of the data. Aims. We study how the use of several stellar-subtraction methods and line fitting approaches can affect the derivation of the main kinematic parameters (velocity and velocity dispersion fields) of the ionized gas component. Methods. The target of this work is the nearby galaxy NGC 2906, observed with the MUSE instrument at the Very Large Telescope (VLT). A sample of twelve spectra is selected from the inner (nucleus) and outer (spiral arms) regions, characterized by different ionization mechanisms. We compare three different methods to subtract the stellar continuum (FIT3D, STARLIGHT and pPXF), combined with one of the following stellar libraries: MILES, STELIB and GRANADA+MILES. Results. The choice of the stellar-subtraction method is the most important ingredient affecting the derivation of the gas kinematics, followed by the choice of the stellar library and by the line-fitting approach. In our data, typical uncertainties in the observed wavelength and width of the Hα and [NII] lines are of the order of ⟨δλ⟩rms ∼ 0.1 Å and ⟨δσ⟩rms ∼ 0.2 Å (i.e., ∼5 and 10 km s−1, respectively). The results obtained from the [NII] line seem to be slightly more robust, as it is less affected by stellar absorption than Hα. All methods considered yield statistically consistent measurements once a mean systemic contribution Δλ¯ = Δσ¯ = 0.2 ΔMUSE is added in quadrature to the line-fitting errors, where ΔMUSE = 1.1 Å ∼50 km s−1, which denotes the instrumental resolution of the MUSE spectra. Conclusions. Although the subtraction of the stellar continuum is critical in order to recover line fluxes, any method (including none) can be used to measure the gas kinematics, as long as an additional component, Δλ¯ = Δσ¯ = 0.2 ΔMUSE, is added to the error budget.

show abstract

Ecological Restoration

Cited by 23 publications

References 3 publications

The VIMOS Ultra-Deep Survey: A major merger origin for the high fraction of galaxies at 2 < z < 6 with two bright clumps

The VIMOS Ultra-Deep Survey: A major merger origin for the high fraction of galaxies at 2 < z < 6 with two bright clumps

Inside Out and Upside-Down: The Roles of Gas Cooling and Dynamical Heating in Shaping the Stellar Age-Velocity Relation

Uncertainties in gas kinematics arising from stellar continuum modeling in integral field spectroscopy data: the case of NGC 2906 observed with VLT/MUSE

Contact Info

Product

Resources

About