The Cool ISM in Elliptical Galaxies. I. A Survey of Molecular Gas

Sage, Leslie J.; Welch, Gary A.; Young, Lisa M.

doi:10.1086/510577

Cited by 74 publications

(92 citation statements)

References 57 publications

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“…The typical molecular gas masses of those nearby earlytype galaxies with detections have been estimated to range between 10 6 M and 10 7 M (Sage et al 2007;Combes et al 2007), corresponding to very low mass fractions. These previous studies focused on "typical" early-type galaxies drawn from the red sequence population (see also, e.g., Faber & Gallagher 1976;Lake & Schommer 1984).…”

Section: Resultsmentioning

confidence: 99%

Destruction of Molecular Gas Reservoirs in Early-Type Galaxies by Active Galactic Nucleus Feedback

Schawinski

Lintott

Thomas

et al. 2008

ApJ

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Residual star formation at late times in early-type galaxies and their progenitors must be suppressed in order to explain the population of red, passively evolving systems we see today. Likewise, residual or newly accreted reservoirs of molecular gas that are fueling star formation must be destroyed. This suppression of star formation in early-type galaxies is now commonly attributed to active galactic nucleus (AGN) feedback wherein the reservoir of gas is heated and expelled during a phase of accretion onto the central supermassive black hole. However, direct observational evidence for a link between the destruction of this molecular gas and an AGN phase has been missing so far. We present new mm-wavelength observations from the IRAM 30 m telescope of a sample of lowredshift SDSS early-type galaxies currently undergoing this process of quenching of late-time star formation. Our observations show that the disappearance of the molecular gas coincides within less than 100 Myr with the onset of accretion onto the black hole and is too rapid to be due to star formation alone. Since our sample galaxies are not associated to powerful quasar activity or radio jets, we conclude that low-luminosity AGN episodes are sufficient to suppress residual star formation in early-type galaxies. This "suppression mode" of AGN feedback is very different from the "truncation mode" linked to powerful quasar activity during early phases of galaxy formation.

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Section: Resultsmentioning

confidence: 99%

Destruction of Molecular Gas Reservoirs in Early-Type Galaxies by Active Galactic Nucleus Feedback

Schawinski

Lintott

Thomas

et al. 2008

ApJ

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“…Stellar recycling arguments suggest that they should contain about ten times the atomic hydrogen mass that they actually do. Additionally, the gas mass is not correlated with the stellar mass, which it would be if recycling were an important source (Ciotti et al 1991;Sage, Welch & Young 2007). Where the recycled gas goes is an unsolved problem.…”

Section: Cold Gas Contentmentioning

confidence: 99%

Physical Properties and Environments of Nearby Galaxies

Blanton

Moustakas

2009

Annu. Rev. Astron. Astrophys.

504

442

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We review the physical properties of nearby, relatively luminous galaxies, using results from newly available massive data sets together with more detailed observations. First, we present the global distribution of properties, including the optical and ultraviolet luminosity, stellar mass, and atomic gas mass functions. Second, we describe the shift of the galaxy population from "late" galaxy types in underdense regions to "early" galaxy types in overdense regions. We emphasize that the scaling relations followed by each galaxy type change very little with environment, with the exception of some minor but detectable effects. The shift in the population is apparent even at the densities of small groups and therefore cannot be exclusively due to physical processes operating in rich clusters. Third, we divide galaxies into four crude types -spiral, lenticular, elliptical, and merging systems -and describe some of their more detailed properties. We attempt to put these detailed properties into the global context provided by large surveys. Contents

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“…Thus, with the cautionary remark that the size of the H 2 gas structure in the three groups may not scale similarly with D 25 , the immediate conclusion one can draw is that in the ellipticals the surface density of molecular gas is, on average, more than one order of magnitude less than in spirals, while it is a factor of about three less in the lenticulars. This conclusion we believe is stronger than the one that can be drawn from the detection rate, which is very sensitive to the sample selection, as discussed in Combes et al (2007); see also Welch & Sage (2003), Sage et al (2007) and references in these papers. An additional important result emerging from these papers is that, among the early type galaxies, the ratio M(H 2 )/L decreases with increasing luminosity L, despite the increase in depth of the potential well.…”

Section: The Molecular Gas Surface Density σmentioning

confidence: 71%

X-ray absorption in Compton-thin AGN: the predictions of a model revisited

Lamastra

Perola

Matt

2008

A&A

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Context. The evidence of a decrease with increasing luminosity in the fraction f abs of absorbed and Compton-thin among X-rayselected (2−10 keV) AGN is observationally well supported, while that of an increase in f abs with redshift is fairly controversial. In a previous paper, the gravitational effect of the SMBH on the molecular interstellar gas, in the central region of the host galaxy, was shown to predict an anti-correlation between f abs and the black-hole mass M BH . Aims. The most recent findings on the distribution of the Eddington ratio λ = L b /L E as a function of M BH and z are used to convert that relationship into one between f abs and both bolometric (L b ) and X-ray (L X ) luminosities at various values of z. Methods. The findings for λ(M BH , z) are properly treated to ensure completeness in the prediction of f abs above a certain luminosity, at values of z = 0.1, 0.35, 0.7, and ≥1. To verify the consequence of these findings alone, we first adopted a distribution of gas surface density Σ, observed in a sample of local spiral galaxies, irrespective of the galaxy morphological type and z. Results. Assuming the Eddington limit, λ = 1, in the λ(M BH , z) distribution as a "natural" cut-off, the predictions are consistent with the existence of an anti-correlation between f abs and L X , but they fail to reproduce an increase in f abs with z. Because the early type galaxies are on average much poorer in molecular gas than late type ones, a quantitative agreement with the local value of f abs requires the existence of a correlation between Σ and the central activity. An increase in typical values of Σ with z, correlated with the activity, might explain an increase in f abs with z. However, f abs could hardly exceed about 0.3 at the highest luminosities.

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The Cool ISM in Elliptical Galaxies. I. A Survey of Molecular Gas

Cited by 74 publications

References 57 publications

Destruction of Molecular Gas Reservoirs in Early-Type Galaxies by Active Galactic Nucleus Feedback

Destruction of Molecular Gas Reservoirs in Early-Type Galaxies by Active Galactic Nucleus Feedback

Physical Properties and Environments of Nearby Galaxies

X-ray absorption in Compton-thin AGN: the predictions of a model revisited

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