The Cool Interstellar Medium in Elliptical Galaxies. Ii. Gas Content in the Volume-Limited Sample and Results From the Combined Elliptical and Lenticular Surveys

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

doi:10.1088/0004-637x/725/1/100

Cited by 77 publications

(75 citation statements)

References 61 publications

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“…The only ETG in our sample that has been detected both in atomic and molecular gas, i.e. the S0 galaxy VCC 1535 (NGC 4526), has a high molecular-to-atomic-gas mass ratio (M H 2 /M HI = 28), consistent with the trend to higher values in this ratio for earlier spirals (Young & Scoville 1991), but considerably higher than the values reported by Welch et al (2010) for about a dozen elliptical and lenticular galaxies. In summary only one ETG in our sample (VCC 1535) has been detected in Hi, H 2 , and dust, while 8 ETG have been detected in both Hi and dust, and 9 ETG in H 2 and dust.…”

Section: Other Ism Componentssupporting

confidence: 85%

TheHerschelVirgo Cluster Survey

Alighieri

Bianchi

Pappalardo

et al. 2013

A&A

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Aims. We study the dust content of a large optical input sample of 910 early-type galaxies (ETG) in the Virgo cluster, also extending to the dwarf ETG, and examine the results in relation to those on the other cold ISM components. Methods. We have searched for far-infrared emission in all galaxies in the input sample using the 250 μm image of the Herschel Virgo Cluster Survey (HeViCS). This image covers a large fraction of the cluster with an area of ∼55 square degrees. For the detected ETG we measured fluxes in five bands from 100 to 500 μm, and estimated the dust mass and temperature with modified black-body fits. Results. Dust is detected above the completeness limit of 25.4 mJy at 250 μm in 46 ETG, 43 of which are in the optically complete part of the input sample. In addition, dust is present at fainter levels in another six ETG. We detect dust in the four ETG with synchrotron emission, including M 87. Dust appears to be much more concentrated than stars and more luminous ETG have higher dust temperatures. Considering only the optically complete input sample and correcting for the contamination by background galaxies, dust detection rates down to the 25.4 mJy limit are 17% for ellipticals, about 40% for lenticulars (S0 + S0a), and around 3% for dwarf ETG. Dust mass does not correlate clearly with stellar mass and is often much greater than expected for a passive galaxy in a closedbox model. The dust-to-stars mass ratio anticorrelates with galaxy luminosity, and for some dwarf ETG reaches values as high as for dusty late-type galaxies. In the Virgo cluster slow rotators appear more likely to contain dust than fast ones. Comparing the dust results with those on Hi there are only eight ETG detected both in dust and in Hi in the HeViCS area; 39 have dust but only an upper limit on Hi, and eight have Hi but only an upper limit on dust. The locations of these galaxies in the cluster are different, with the dusty ETG concentrated in the densest regions, while the Hi rich ETG are at the periphery.

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Section: Other Ism Componentssupporting

confidence: 85%

TheHerschelVirgo Cluster Survey

Alighieri

Bianchi

Pappalardo

et al. 2013

A&A

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“…For galaxies taken from the literature, we give only the H 2 mass corrected to our assumed distance and other quantities may be found in the original sources. Data sources: 1 = this paper, 2 =Combes et al (2007), 3 =Welch & Sage (2003), 4 =Sage et al (2007), 5 =Wiklind et al (1995), 6 =Young (2002), and 7 =Welch et al (2010). The table is also available in its entirety at the project website: http://purl.org/atlas3d…”

Section: Datamentioning

confidence: 99%

The ATLAS3D project - IV. The molecular gas content of early-type galaxies★

Young

Bureau

Davis

et al. 2011

Monthly Notices of the Royal Astronomical Society

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302

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We have carried out a survey for CO J= 1–0 and J= 2–1 emission in the 260 early‐type galaxies of the volume‐limited ATLAS3D sample, with the goal of connecting their star formation and assembly histories to their cold gas content. This is the largest volume‐limited CO survey of its kind and is the first to include many Virgo cluster members. Sample members are dynamically hot galaxies with a median stellar mass ∼3 × 1010 M⊙; they are selected by their morphology rather than colour, and the bulk of them lie on the red sequence. The overall CO detection rate is 56/259 = 0.22 ± 0.03, with no dependence on the K luminosity and only a modest dependence on the dynamical mass. There are a dozen CO detections among the Virgo cluster members; statistical analysis of their H2 mass distributions and their dynamical status within the cluster shows that the cluster’s influence on their molecular masses is subtle at best, even though (unlike spirals) they seem to be virialized within the cluster. We suggest that the cluster members have retained their molecular gas through several Gyr residences in the cluster. There are also a few extremely CO‐rich early‐type galaxies with H2 masses ≳109 M⊙ and these are in low‐density environments. We do find a significant trend between the molecular content and stellar specific angular momentum. The galaxies of low angular momentum also have low CO detection rates, suggesting that their formation processes were more effective at destroying the molecular gas or preventing its re‐accretion. We speculate on the implications of these data for the formation of various subclasses of early‐type galaxies.

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“…They observed the SAURON sample of galaxies (a representative sample of 48 ETGs which had been observed with the SAURON integral‐field spectrograph; see de Zeeuw et al 2002 for full details) and reported a molecular gas detection rate of 28 per cent [with a CO(1–0) sensitivity of 3 mK T * a in a 30 km s −1 channel]. The survey of Welch, Sage & Young (2010) (which combined and added to the results of Welch & Sage 2003; Sage & Welch 2006; Sage, Welch & Young 2007) was the first published volume‐limited sample, which found a detection rate of 26 per cent for ETGs within 20 Mpc (with a similar sensitivity).…”

Section: Introductionmentioning

confidence: 99%

The ATLAS3D project - X. On the origin of the molecular and ionized gas in early-type galaxies

Davis¹,

Alatalo²,

Sarzi³

et al. 2011

Monthly Notices of the Royal Astronomical Society

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287

389

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We make use of interferometric CO and H i observations, and optical integral‐field spectroscopy from the ATLAS3D survey, to probe the origin of the molecular and ionized interstellar medium (ISM) in local early‐type galaxies. We find that 36 ± 5 per cent of our sample of fast‐rotating early‐type galaxies have their ionized gas kinematically misaligned with respect to the stars, setting a strong lower limit on the importance of externally acquired gas (e.g. from mergers and cold accretion). Slow rotators have a flat distribution of misalignments, indicating that the dominant source of gas is external. The molecular, ionized and atomic gas in all the detected galaxies are always kinematically aligned, even when they are misaligned from the stars, suggesting that all these three phases of the ISM share a common origin. In addition, we find that the origin of the cold and warm gas in fast‐rotating early‐type galaxies is strongly affected by environment, despite the molecular gas detection rate and mass fractions being fairly independent of group/cluster membership. Galaxies in dense groups and the Virgo cluster nearly always have their molecular gas kinematically aligned with the stellar kinematics, consistent with a purely internal origin (presumably stellar mass loss). In the field, however, kinematic misalignments between the stellar and gaseous components indicate that at least 42 ± 5 per cent of local fast‐rotating early‐type galaxies have their gas supplied from external sources. When one also considers evidence of accretion present in the galaxies’ atomic gas distributions, ≳46 per cent of fast‐rotating field ETGs are likely to have acquired a detectable amount of ISM from accretion and mergers. We discuss several scenarios which could explain the environmental dichotomy, including preprocessing in galaxy groups/cluster outskirts and the morphological transformation of spiral galaxies, but we find it difficult to simultaneously explain the kinematic misalignment difference and the constant detection rate. Furthermore, our results suggest that galaxy mass may be an important independent factor associated with the origin of the gas, with the most massive fast‐rotating galaxies in our sample (MK≲−24 mag; stellar mass of ≈8 × 1010 M⊙) always having kinematically aligned gas. This mass dependence appears to be independent of environment, suggesting it is caused by a separate physical mechanism.

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The Cool Interstellar Medium in Elliptical Galaxies. Ii. Gas Content in the Volume-Limited Sample and Results From the Combined Elliptical and Lenticular Surveys

Cited by 77 publications

References 61 publications

TheHerschelVirgo Cluster Survey

TheHerschelVirgo Cluster Survey

The ATLAS3D project - IV. The molecular gas content of early-type galaxies★

The ATLAS3D project - X. On the origin of the molecular and ionized gas in early-type galaxies

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