Shock formation of the broad emission-line regions in QSOs and active galactic nuclei

Perry, J. J.; Dyson, J. E.

doi:10.1093/mnras/213.3.665

Cited by 90 publications

(73 citation statements)

References 0 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…3 demonstrate that it is possible to cool shocked supernova ejecta to T ∼ 10 4 K in the inner regions of a QSO. Although our results differ from the original proposals of Dyson & Perry (1982) and Perry & Dyson (1985), which were for the shocked ambient medium to cool, the resulting cool gas nevertheless has properties (densities, column densities, velocities and ionization parameters) compatible with those inferred for gas emitting the high ionization lines in QSOs.…”

Section: Discussioncontrasting

confidence: 93%

“…We also note that the combined wind from a group of early-type stars may provide the necessary conditions for the formation of cool regions. We anticipate that this scenario will be more relevant in the nuclei of Seyfert galaxies, since supernova explosions will evacuate all but the most tightly bound gas in them (Perry & Dyson 1985). Finally, it is clear from our models that while the supernova-QSO wind interaction is conceptually simple, the BELR is likely to be a very complicated region in practice.…”

Section: Discussionmentioning

confidence: 85%

“…In earlier work it was shown that for typical QSO parameters the power going into supernova remnants is comparable to that of the QSO wind, but is much less than the bolometric QSO luminosity (Perry & Dyson 1985). However, it is more difficult to estimate whether emission from the SN would be visible above the QSO in a specific waveband.…”

Section: Discussionmentioning

confidence: 99%

See 2 more Smart Citations

The formation of broad emission line regions in supernova-QSO wind interactions

Pittard

Dyson

Falle

et al. 2003

A&A

Self Cite

View full text Add to dashboard Cite

Abstract. One aspect of supernova remnant evolution that is relatively unstudied is the influence of an AGN environment. A high density ambient medium and a nearby powerful continuum source will assist the cooling of shocked ejecta and sweptup gas. Motion of the surrounding medium relative to the remnant will also affect the remnant morphology. In an extension to previous work we have performed 2D hydrodynamical calculations of SNR evolution in an AGN environment, and have determined the evolutionary behaviour of cold gas in the remnant. The cold gas will contribute to the observed broad line emission in AGNs, and we present preliminary theoretical line profiles from our calculations. A more detailed comparison with observations will be performed in future work. The SNR-AGN interaction may be also useful as a diagnostic of AGN winds.

show abstract

Section: Discussioncontrasting

confidence: 93%

Section: Discussionmentioning

confidence: 85%

See 1 more Smart Citation

The formation of broad emission line regions in supernova-QSO wind interactions

Pittard

Dyson

Falle

et al. 2003

A&A

Self Cite

View full text Add to dashboard Cite

show abstract

“…On the theoretical side, models such as those of Perry & Dyson (1985) and Norman & Scoville (1988) propose that a nuclear young stellar cluster is the reservoir of fuel for the active galactic nucleus (AGN) in the nucleus.…”

Section: Introductionmentioning

confidence: 99%

The Frequency of Nuclear Star Formation in Seyfert 2 Galaxies

Storchi‐Bergmann

Raimann

Bica

et al. 2000

ApJ

View full text Add to dashboard Cite

We investigate the detectability of starburst signatures in the nuclear spectrum of Seyfert 2 galaxies by constructing spectral models in the wavelength range jj3500È4100, combining the spectrum of a bulge population (of age B10 Gyr) with that of younger stellar populations, spanning ages from B3 Myr to 1 Gyr. The major constraints in the analysis are (1) the continuum ratio jj3660/4020, which efficiently discriminates between models combining a bulge spectrum with a stellar population younger than B50 Myr and those with older stellar populations ; (2) the presence of the Balmer lines H8, H9, and H10 in absorption, which are unambiguous signatures of stellar populations with ages in the range 10 MyrÈ1 Gyr for the relevant metallicities. Their detectability depends both on the age of the young component and on its contribution to the total Ñux relative to that of the bulge. We also construct models combining the bulge template with a power-law (PL) continuum, which is observed in some Seyfert 2 galaxies in polarized light, contributing with typically 10%È40% of the Ñux at 4020We conclude that such con-A . tinuum cannot be distinguished from that of a very young stellar population (age ¹ 10 Myr), contributing with less than B0.02% of the mass of the bulge. The models are compared with nuclear spectraÈcorresponding to a radius of 200È300 pc at the galaxyÈof 20 Seyfert 2 galaxies, in which we speciÐcally look for the signatures above of young-to intermediate-aged stellar populations. We Ðnd them in 10 galaxies, thus 50% of the sample. But only in six cases (30% of the sample) can they be attributed to young stars (age \ 500 Myr) : Mrk 1210, ESO 362-G8, NGC 5135, NGC 5643, NGC 7130, and NGC 7582. In the remaining four cases, the signatures are caused by intermediate-aged stars (B1 Gyr). We Ðnd a tendency for the young stars to be found more frequently among the late-type Seyfert galaxies, a well-known e †ect in the nuclei of normal galaxies. This tendency is supported by a comparison between the equivalent widths (W ) of absorption lines of the nuclear spectra of the Seyfert 2 galaxies with those of normal galaxies of the same Hubble type. For the late-type galaxies, the W values of the Seyfert galaxies are within the observed range of the normal galaxies, suggesting a similar stellar population. On the other hand, the W values are lower than those of the normal galaxies for seven out of the 11 Seyferts in early-type galaxies.

show abstract

“…magnetic fields could play a role; Rees 1987), or they might not be confined at all. Confinement is unnecessary if the BLR clouds are continuously produced (e.g., Perry & Dyson 1985;Murray & Chiang 1995). Generally, all suggested models including variants of the KMT approach, still suffer from some unsolved problems.…”

Section: Two-phase Nlr Of Ngc 4151mentioning

confidence: 99%

A two-phase model for the narrow line region of NGC 4151

Komossa

2001

A&A

View full text Add to dashboard Cite

Abstract. NGC 4151 is one of the brightest and best-studied Seyfert galaxies. Here, we present a two-phase model of the narrow-line region (NLR) of NGC 4151. This study is motivated by (i) the fact that the X-ray spectrum of NGC 4151 is among the flattest known for Seyferts, and (ii) the recent Chandra detection of an X-ray narrow-line region in this galaxy. X-ray spectra as flat as that of NGC 4151 (Γx −1.5) are expected to favor the presence of two gas phases in pressure equilibrium (Krolik et al. 1981). In the present study, we show that a pronounced two-phase equilibrium develops in the extended emission-line region if we use the observed multi-wavelength spectrum of NGC 4151 to ionize the clouds. The material is stable to isobaric perturbations over a wide range of temperatures. We therefore propose that such a condition has arisen in the NLR of NGC 4151, and that it explains the detection of hot, extended X-ray gas which we identify as the NLR-cloud confining medium.

show abstract

Shock formation of the broad emission-line regions in QSOs and active galactic nuclei

Cited by 90 publications

References 0 publications

The formation of broad emission line regions in supernova-QSO wind interactions

The formation of broad emission line regions in supernova-QSO wind interactions

The Frequency of Nuclear Star Formation in Seyfert 2 Galaxies

A two-phase model for the narrow line region of NGC 4151

Contact Info

Product

Resources

About