Dust as a tracer of gas in galaxies

AbstractWe use a sample of 36 galaxies to study empirical relations between Herschel infrared (IR) luminosities and the total mass of the interstellar gas (H2 + HI). Such a comparison provides a simple empirical relationship without introducing the uncertainty of dust model fitting. We find tight correlations, and provide fits to these relations, between Herschel luminosities and the total gas mass integrated over entire galaxies, with the tightest, almost linear, correlation found for the longest wavelength data (SPIRE500). However, we find that accounting for the gas-phase metallicity (affecting the dust-to-gas ratio) is crucial when applying these relations to low-mass, and presumably high-redshift, galaxies. When examining these relations as a function of galactocentric radius, we find the same correlations, albeit with a larger scatter, up to radius of r ∼ 0.7r25 (containing most of a galaxy's baryonic mass). The tight relations found for the bulk of the galaxy's baryonic content suggest that total gas masses of disk-like (non-merging/ULIRG) galaxies can be inferred from far-infrared continuum measurements in situations where only the latter are available. This work is to appear in Groves et al. (2014).

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Observations of galaxies at z>6. The properties of large, spectroscopic samples

Proceedings of the International Astronomical Union ◽

10.1017/s1743921307010344 ◽

2006 ◽

Vol 2 (14) ◽

pp. 252-252

Author(s):

Esther M. Hu ◽

Lennox L. Cowie ◽

Yuko Kakazu

Keyword(s):

High Redshift ◽

Broad Band ◽

Ccd Camera ◽

Far Infrared ◽

Current Status ◽

Wide Field ◽

High Redshift Galaxies ◽

Field Samples ◽

Multi Wavelength ◽

Redshift Galaxies

AbstractObserved properties of spectroscopically confirmed galaxies at z≫5 and z≫6 based on selection from deep, multi-wavelength wide-field samples provide a picture of the current status of the properties of high-redshift galaxies and their evolution to yet higher redshifts.In the current presentation, we use results of deep, wide-field spectroscopy with the multi-object Deimos spectrograph on Keck in combination with deep, wide-field multi-color imaging studies using the SuprimeCam CCD camera of Subaru for a number of fields, to evaluate the luminosity function of high-redshift galaxies and its evolution at z>6. High-redshift candidates are selected using both narrow-band Lyman alpha emission and broad-band colors with a high success-rate from a number of SuprimeCam (0.5 degree FOV) fields.Luminosity functions and Lymanα emission line profiles and equivalent widths appear similar between samples at z≃5.7 and z≃6.5, and the galaxy distribution is structured both spatially and in redshift. A large amount of cosmic variance is seen in the distribution of z≫6 galaxies from field to field.The observed properties are discussed in relationship to their impact on strategies for complementary optical surveys of high-redshift galaxies, and in relationship to surveys at very different wavelengths (X-ray, far-infrared, and submillimeter) that cover the same regions.

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MEASURING STAR FORMATION RATES AND FAR-INFRARED COLORS OF HIGH-REDSHIFT GALAXIES USING THE CO(7–6) AND [N II] 205 μ m LINES

The Astrophysical Journal ◽

10.1088/2041-8205/802/1/l11 ◽

2015 ◽

Vol 802 (1) ◽

pp. L11 ◽

Cited By ~ 22

Author(s):

Nanyao Lu ◽

Yinghe Zhao ◽

C. Kevin Xu ◽

Yu Gao ◽

Tanio Díaz-Santos ◽

...

Keyword(s):

Star Formation ◽

High Redshift ◽

Far Infrared ◽

High Redshift Galaxies ◽

Redshift Galaxies

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Predicting FIR lines from simulated galaxies

Monthly Notices of the Royal Astronomical Society ◽

10.1093/mnras/staa1842 ◽

2020 ◽

Vol 496 (4) ◽

pp. 5160-5175 ◽

Cited By ~ 4

Author(s):

Alessandro Lupi ◽

Andrea Pallottini ◽

Andrea Ferrara ◽

Stefano Bovino ◽

Stefano Carniani ◽

...

Keyword(s):

State Of The Art ◽

High Redshift ◽

Line Emission ◽

Far Infrared ◽

Emission Lines ◽

Cosmological Simulations ◽

High Redshift Galaxies ◽

Emission Models ◽

Excellent Tool ◽

Non Equilibrium

ABSTRACT Far-infrared (FIR) emission lines are a powerful tool to investigate the properties of the interstellar medium, especially in high-redshift galaxies, where ALMA observations have provided unprecedented information. Interpreting such data with state-of-the-art cosmological simulations post-processed with cloudy, has provided insights on the internal structure and gas dynamics of these systems. However, no detailed investigation of the consistency and uncertainties of this kind of analysis has been performed to date. Here, we compare different approaches to estimate FIR line emission from state-of-the-art cosmological simulations, either with cloudy or with on-the-fly non-equilibrium chemistry. We find that [C ii]158μ predictions are robust to the model variations we explored. [O i] emission lines, that typically trace colder and denser gas relative to [C ii]158μ, are instead model dependent, as these lines are strongly affected by the thermodynamic state of the gas and non-equilibrium photoionization effects. For the same reasons, [O i] lines represent an excellent tool to constrain emission models, hence future observations targeting these lines will be crucial.

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On the far-infrared metallicity diagnostics: applications to high-redshift galaxies

Monthly Notices of the Royal Astronomical Society ◽

10.1093/mnras/stx2311 ◽

2017 ◽

Vol 473 (1) ◽

pp. 20-29 ◽

Cited By ~ 14

Author(s):

D. Rigopoulou ◽

M. Pereira-Santaella ◽

G. E. Magdis ◽

A. Cooray ◽

D. Farrah ◽

...

Keyword(s):

High Redshift ◽

Far Infrared ◽

High Redshift Galaxies ◽

Redshift Galaxies

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Far-infrared line emission from high-redshift galaxies

Monthly Notices of the Royal Astronomical Society ◽

10.1093/mnras/stt828 ◽

2013 ◽

Vol 433 (2) ◽

pp. 1567-1572 ◽

Cited By ~ 45

Author(s):

Livia Vallini ◽

Simona Gallerani ◽

Andrea Ferrara ◽

Sunghye Baek

Keyword(s):

High Redshift ◽

Line Emission ◽

Far Infrared ◽

High Redshift Galaxies ◽

Redshift Galaxies

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High Redshift Radio Galaxies

Symposium - International Astronomical Union ◽

10.1017/s0074180900109957 ◽

1996 ◽

Vol 168 ◽

pp. 79-87

Author(s):

James S. Dunlop

Keyword(s):

High Redshift ◽

Spatial Association ◽

Radio Galaxies ◽

Elliptical Galaxies ◽

Powerful Radio ◽

High Redshift Galaxies ◽

3 Dimensional ◽

Baryonic Mass ◽

Radio Power

The potentially important role of jet-cloud interactions in determining the appearance of high-redshift radio galaxies is discussed and investigated via new 3-dimensional simulations of off-axis jet-cloud collisions. The results indicate that the most powerful radio sources are likely to be observed during or shortly after a jet-cloud interaction, and that such interactions can explain both the radio structures and the spatial association between optical and radio light found in powerful radio galaxies at high redshift. It is argued that, due to the radio-power dependence of such complicating effects, the optical-infrared colours and morphologies of very radio-luminous high-redshift galaxies can tell us essentially nothing about their evolutionary state. Either one must study much less radio-luminous sources in which the AGN-induced contamination is minimised, or one must attempt to determine what fraction of the baryonic mass of the radio galaxy has been converted into stars at the epoch of observation. Recent observations aimed at performing the latter experiment on two well-known high-redshift radio galaxies (4C 41.17 & B2 0902+34) are described. It is concluded that at present there exists no clear evidence that either of these famous galaxies is ‘primæval’; on the contrary, the continued low-dispersion of the infrared Hubble diagram atz> 2 points toward a much higher redshift of formation for elliptical galaxies.

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Scaling Relations of Dwarf Galaxies without Supernova-Driven Winds

Proceedings of the International Astronomical Union ◽

10.1017/s1743921307014068 ◽

2007 ◽

Vol 3 (S244) ◽

pp. 256-265

Author(s):

K. Tassis ◽

A. V. Kravtsov ◽

N. Y. Gnedin

Keyword(s):

Surface Brightness ◽

Dwarf Galaxies ◽

High Redshift ◽

Formation Rate ◽

Critical Density ◽

Appreciable Effect ◽

High Redshift Galaxies ◽

Energy Feedback ◽

Low Mass ◽

Density Threshold

AbstractNearby dwarf galaxies exhibit tight correlations between their global stellar and dynamical properties, such as circular velocity, mass-to-light ratio, stellar mass, surface brightness, and metallicity. Such correlations have often been attributed to gas or metal-rich outflows driven by supernova energy feedback to the interstellar medium. We use high-resolution cosmological simulations of high-redshift galaxies with and without energy feedback, as well as analytic modeling, to investigate whether the observed correlations can arise without supernova-driven outflows. We find that the simulated dwarf galaxies exhibit correlations similar to those observed as early as z ≈ 10 and the addition of realistic levels of supernova energy feedback has no appreciable effect on these correlations. We also show that the correlations can be well reproduced by our analytic model that accounts for gas inflow but without outflows, and star formation rate obeying the Kennicutt-Schmidt law with a critical density threshold. We argue that correlations in simulated galaxies arise due to the increasingly inefficient conversion of gas into stars in low-mass dwarf galaxies rather than supernova-driven outflows.

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Hierarchical fragmentation in high redshift galaxies revealed by hydrodynamical simulations

Monthly Notices of the Royal Astronomical Society ◽

10.1093/mnras/stab272 ◽

2021 ◽

Author(s):

Baptiste Faure ◽

Frédéric Bournaud ◽

Jérémy Fensch ◽

Emanuele Daddi ◽

Manuel Behrendt ◽

...

Keyword(s):

Gravitational Lensing ◽

Hubble Space Telescope ◽

High Redshift ◽

High Redshift Galaxies ◽

Star Forming ◽

Low Mass ◽

Hydrodynamical Simulations ◽

Gas Clusters ◽

Very High ◽

Redshift Galaxies

Abstract High-redshift star-forming galaxies have very different morphologies compared to nearby ones. Indeed, they are often dominated by bright star-forming structures of masses up to 108 − 9 M⊙ dubbed Â«giant clumpsÂ». However, recent observations questioned this result by showing only low-mass structures or no structure at all. We use Adaptative Mesh Refinement hydrodynamical simulations of galaxies with parsec-scale resolution to study the formation of structures inside clumpy high-redshift galaxies. We show that in very gas-rich galaxies star formation occurs in small gas clusters with masses below 107 − 8 M⊙ that are themselves located inside giant complexes with masses up to 108 and sometimes 109 M⊙ . Those massive structures are similar in mass and size to the giant clumps observed in imaging surveys, in particular with the Hubble Space Telescope. Using mock observations of simulated galaxies, we show that at very high resolution with instruments like the Atacama Large Millimeter Array or through gravitational lensing, only low-mass structures are likely to be detected, and their gathering into giant complexes might be missed. This leads to the non-detection of the giant clumps and therefore introduces a bias in the detection of these structures. We show that the simulated giant clumps can be gravitationally bound even when undetected in mocks representative for ALMA observations and HST observations of lensed galaxies. We then compare the top-down fragmentation of an initially warm disc and the bottom-up fragmentation of an initially cold disc to show that the process of formation of the clumps does not impact their physical properties.

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