Skip to main content Accessibility help
×
Home
Hostname: page-component-5bf98f6d76-slc4r Total loading time: 5.639 Render date: 2021-04-21T11:59:18.928Z Has data issue: true Feature Flags: { "shouldUseShareProductTool": true, "shouldUseHypothesis": true, "isUnsiloEnabled": true, "metricsAbstractViews": false, "figures": false, "newCiteModal": false, "newCitedByModal": true }

Matter–Bounded Photoionized Clouds

Published online by Cambridge University Press:  25 May 2016

L. Binette
Affiliation:
1 Observatoire de Lyon - 9 av. Charles André F- 69561 Saint-Genis-Laval Cedex, France
A.S. Wilson
Affiliation:
2 Astronomy Department - University of Maryland College Park, MD 20742, USA
T. Storchi-Bergmann
Affiliation:
3 Instituto de Fisica - UFRGS, Campus do Vale 91500 Porto Alegre, RS, Brasil

Extract

The extended ionized gas in Seyfert and Radio-Galaxies is characterized by large values of the ratio He ii/Hβ, which exceeds the value predicted by the standard photoionization model in which the ionizing continuum consists of a power-law. This has lead to the suggestion of considering a matter-bounded (MB) component for explaining such extreme values. We now find that it is also possible to resolve the temperature problem if the thickness and the ionization parameter of the MB is appropriately selected. Adopting a canonical power law (α= −1.3) and solar abundances (Z=l), we can account for the observed trends in excitation (represented for example by the ratio [0 ii]/[0 iii] in Fig. 1)) by varying the relative number of MB clouds (which emit the high excitation lines Civ, [Ne v], He ii… and most of [O iii]) versus the number of ionization-bounded (IB) clouds (which emit [N ii],[S ii] [O ii], [O i]…). We obtain a one-parameter sequence (solid line) which is function of the weight AM/I of the MB component relative to the IB component. This AM/I–sequence successfully reproduces the observed range in He ii/Hβ. Note the failure of the traditional U–sequence (long dashed line). Fig. 2 indicates that we can also reproduce the ratio ROIII= [O III]λ4363/[O iii]λ5007 and therefore resolve the temperature problem. Interestingly, our model indicates a temperature difference of 5 000 K between the IB component ([N ii] temperature ≃ 10 000 K) and the MB component ([O iii] temperature ≃ 15 000 K) while the traditional U–sequence predicts a difference of only 1 000 K. Such difference of 5 000 K has been reported in the extended gas of Cygnus A.

Type
Relation between Radio and Other Wavelenghts
Copyright
Copyright © Kluwer 1996 

References

1. Binette, L., Wilson, A. S. and Storchi-Bergmann, T., 1996. A&A , submitted.Google Scholar
2. Morganti, R., Robinson, A., Fosbury, R. A. E., di Serego Alighieri, S., Tadhunter, C. N., and Malin, D. F., 1991. MNRAS , 249, 91.CrossRefGoogle Scholar
3. Tadhunter, C.N., Robinson, A. and Morganti, R., 1989. ESO Conf. and Workshop Proc. no.32, Garching, p 293.Google Scholar
4. Tadhunter, C. N., Metz, S. and Robinson, A., 1994. MNRAS , 268, 989.CrossRefGoogle Scholar
5. Viegas, S. M. and Prieto, A., 1992. MNRAS , 258, 483.CrossRefGoogle Scholar

Full text views

Full text views reflects PDF downloads, PDFs sent to Google Drive, Dropbox and Kindle and HTML full text views.

Total number of HTML views: 0
Total number of PDF views: 46 *
View data table for this chart

* Views captured on Cambridge Core between September 2016 - 21st April 2021. This data will be updated every 24 hours.

You have Access

Send article to Kindle

To send this article to your Kindle, first ensure no-reply@cambridge.org is added to your Approved Personal Document E-mail List under your Personal Document Settings on the Manage Your Content and Devices page of your Amazon account. Then enter the ‘name’ part of your Kindle email address below. Find out more about sending to your Kindle. Find out more about sending to your Kindle.

Note you can select to send to either the @free.kindle.com or @kindle.com variations. ‘@free.kindle.com’ emails are free but can only be sent to your device when it is connected to wi-fi. ‘@kindle.com’ emails can be delivered even when you are not connected to wi-fi, but note that service fees apply.

Find out more about the Kindle Personal Document Service.

Matter–Bounded Photoionized Clouds
Available formats
×

Send article to Dropbox

To send this article to your Dropbox account, please select one or more formats and confirm that you agree to abide by our usage policies. If this is the first time you use this feature, you will be asked to authorise Cambridge Core to connect with your <service> account. Find out more about sending content to Dropbox.

Matter–Bounded Photoionized Clouds
Available formats
×

Send article to Google Drive

To send this article to your Google Drive account, please select one or more formats and confirm that you agree to abide by our usage policies. If this is the first time you use this feature, you will be asked to authorise Cambridge Core to connect with your <service> account. Find out more about sending content to Google Drive.

Matter–Bounded Photoionized Clouds
Available formats
×
×

Reply to: Submit a response


Your details


Conflicting interests

Do you have any conflicting interests? *