Imaging observations of gas and dust in NGC 4696 and implications for cooling flow models

Sparks, W. B.; Macchetto, F.; Golombek, Daniel

doi:10.1086/167890

Cited by 137 publications

(179 citation statements)

References 0 publications

Supporting

Mentioning

167

Contrasting

Order By: Relevance

“…This correlation is in line with the model proposed by Sparks & Collier-Cameron (1988) and Sparks, Macchetto, & Golombek (1989), in which thermal electron conduction causes energy to Ñow from the hot coronal component into the cold gas, exciting it into emission (while cooling the hot gas). The data presented in Paper I show indeed an excellent agreement between the observed Ha ] [N II] Ñuxes and those predicted from the X-ray Ñuxes using this model.…”

Section: Introductionsupporting

confidence: 90%

A Survey of the Interstellar Medium in Early‐Type Galaxies. III. Stellar and Gas Kinematics

Caon

Macchetto

Pastoriza

2000

ASTROPHYS J SUPPL S

105

138

View full text Add to dashboard Cite

We present gaseous and stellar kinematics for 14 gas-rich early-type galaxies. Half of the sample exhibit irregular gaseous velocity proÐles ; gas/star counter-rotation is visible in Ðve galaxies. We also Ðnd Ðve counter-rotating stellar cores, while Ðve more galaxies display inner components kinematically decoupled from the main stellar body. We interpret our results as an indication that the ionized gas is of external origin, is generally not in equilibrium, and may have been acquired recently. The merging or accretion events that brought the gas into the galaxy have also a †ected the stellar kinematics.

show abstract

Section: Introductionsupporting

confidence: 90%

A Survey of the Interstellar Medium in Early‐Type Galaxies. III. Stellar and Gas Kinematics

Caon

Macchetto

Pastoriza

2000

ASTROPHYS J SUPPL S

105

138

View full text Add to dashboard Cite

show abstract

“…Studies of optical line emission in the central regions of elliptical galaxies reveal chaotic gas kinematics, typically about 0.2-0.4 of the sound speed in the hot gas (Caon, Macchetto, & Pastoriza 2000), and since small, optically visible line-emitting regions at T $ 10 4 K are likely to be strongly coupled to the ambient gas, as some models predict (Sparks et al 1989) and as the clear correlation between H +[N ii] and X-ray luminosities suggests, the hot gas should share the same turbulent velocities. The first clear example of resonant scattering, acting on the 2p 3d line of Fe xvii at 15.0 Å (0.83 keV), has been recently found in the giant elliptical galaxy NGC 4636 (Xu et al 2002) using the reflection grating spectrometer (RGS) on board XMM-Newton and measuring the cross-dispersion profile of the ratio between an optically thin emission blend, the two 2p 3s lines of Fe xvii at 17.0-17.1 Å (0.73 keV), and the optically thick line at 15.0 Å .…”

Section: Discussionmentioning

confidence: 99%

Ni Abundance in the Core of the Perseus Cluster: An Answer to the Significance of Resonant Scattering

Gastaldello

Molendi²

2004

ApJ

View full text Add to dashboard Cite

Using an XMM-Newton observation of the Perseus cluster we show that the excess in the flux of the 7-8 keV line complex previously detected by ASCA and BeppoSAX is due to an overabundance of nickel rather than to an anomalously high Fe He /Fe He ratio. This observational fact leads to the main result that resonant scattering, which was assumed to be responsible for the supposed anomalous Fe He /Fe He ratio, is no longer required. The absence of resonant scattering points toward the presence of significant gas motions (either turbulent or laminar) in the core of the Perseus Cluster.

show abstract

“…Tran et al 2001) tends to exclude "cooling flows" as the origin of the warm gas in E/S0 galaxies (Goudfrooij 1999). In the scenarios proposed by Sparks et al (1989) and de Jong et al (1990), the dusty filaments can arise from the interaction of a small gas-rich galaxy with the giant elliptical, or from a tidal accretion event in which the gas and dust are stripped from a passing spiral (see e.g. Domingue et al 2003;Tal et al 2009).…”

Section: Introductionmentioning

confidence: 99%

Nearby early-type galaxies with ionized gas

Annibali

Bressan

Rampazzo

et al. 2010

A&A

121

162

View full text Add to dashboard Cite

Aims. A significant fraction of early-type galaxies (ETGs) exhibit emission lines in their optical spectra. We attempt to identify the producing the emission mechanism and the ionized gas in ETGs, and its connection with the host galaxy evolution. Methods. We analyzed intermediate-resolution optical spectra of 65 ETGs, mostly located in low density environments and exhibiting spectros-copic diagnostic lines of ISM from which we had previously derived stellar population properties. To extract the emission lines from the galaxy spectra, we developed a new fitting procedure that accurately subtracts the underlying stellar continuum, and accounts for the uncertainties caused by the age-metallicity degeneracy. Results. Optical emission lines are detected in 89% of the sample. The incidence and strength of emission correlate with neither the E/S0 classification, nor the fast/slow rotator classification. By means of the classical [OIII]/Hβ versus [NII]/Hα diagnostic diagram, the nuclear galaxy activity is classified such that 72% of the galaxies with emission are LINERs, 9% are Seyferts, 12% are composite/transition objects, and 7% are non-classified. Seyferts have young luminostiy-weighted ages ( 5 Gyr), and appear, on average, significantly younger than LINERs and composites. Excluding the Seyferts from our sample, we find that the spread in the ([OIII], Hα, or [NII]) emission strength increases with the galaxy central velocity dispersion σ c . Furthermore, the [NII]/Hα ratio tends to increase with σ c . The [NII]/Hα ratio decreases with increasing galactocentric distance, indicative of either a decrease in the nebular metallicity, or a progressive "softening" of the ionizing spectrum. The average nebular oxygen abundance is slightly less than solar, and a comparison with the results obtained in Paper III from Lick indices shows that it is ≈0.2 dex lower than that of stars. Conclusions. The nuclear (r < r e /16) emission can be attributed to photoionization by PAGB stars alone only for ≈22% of the LINER/composite sample. On the other hand, we cannot exclude an important role of PAGB star photoionization at larger radii. For the major fraction of the sample, the nuclear emission is consistent with excitation caused by either a low-accretion rate AGN or fast shocks (200-500 km s −1 ) in a relatively gas poor environment (n 100 cm −3 ), or both. The derived [SII]6717/6731 ratios are consistent with the low gas densities required by the shock models. The derived nebular metallicities are indicative of either an external origin of the gas, or an overestimate of the oxygen yields by SN models.

show abstract

Imaging observations of gas and dust in NGC 4696 and implications for cooling flow models

Cited by 137 publications

References 0 publications

A Survey of the Interstellar Medium in Early‐Type Galaxies. III. Stellar and Gas Kinematics

A Survey of the Interstellar Medium in Early‐Type Galaxies. III. Stellar and Gas Kinematics

Ni Abundance in the Core of the Perseus Cluster: An Answer to the Significance of Resonant Scattering

Nearby early-type galaxies with ionized gas

Contact Info

Product

Resources

About