Skip to main content Accessibility help
×
Home
Hostname: page-component-cf9d5c678-ttsf8 Total loading time: 0.242 Render date: 2021-07-28T18:15:34.769Z Has data issue: true Feature Flags: { "shouldUseShareProductTool": true, "shouldUseHypothesis": true, "isUnsiloEnabled": true, "metricsAbstractViews": false, "figures": true, "newCiteModal": false, "newCitedByModal": true, "newEcommerce": true, "newUsageEvents": true }

A UV Flare at the Center of the Elliptical Galaxy NGC 4552

Published online by Cambridge University Press:  25 May 2016

Lucio M. Buson
Affiliation:
Osservatorio di Capodimonte, Napoli, Italy
Francesco Bertola
Affiliation:
Dipartimento di Astronomia, Università di Padova, Padova, Italy
David Burstein
Affiliation:
Department of Physics & Astronomy, Arizona State University, Tempe, AZ, USA
Michele Cappellari
Affiliation:
Dipartimento di Astronomia, Università di Padova, Padova, Italy
Sperello di Serego Alighieri
Affiliation:
Osservatorio di Arcetri, Firenze, Italy
Laura Greggio
Affiliation:
Dipartimento di Astronomia, Università di Bologna, Bologna, Italy Sternwarte der Universität München, München, Germany
Alvio Renzini
Affiliation:
European Southern Observatory, Garching bei München, Germany

Abstract

A self-consistent analysis of near-UV, HST/FOC images of the elliptical galaxy NGC 4552 is used to show that its central spike has brightened by a factor ˜ 4.5 between 1991 and 1993, and has decreased its luminosity by a factor ˜ 2.0 between 1993 and 1996. A strong UV continuum over the energy distribution of the underlying galaxy is concurrently revealed shortward of λ ˜ 3200 Å by our FOS spectra extending from the near-UV to red wavelengths. Nuclear emission-line profiles of both permitted and forbidden lines are best modelled with a combination of broad and narrow components, with FWHM of ˜ 3000 km s−1 and ˜ 700 km s−1, respectively. Current diagnostics based on the emission line intensity ratios definitely places the spike among AGNs, just at the border between Seyferts and LINERs. This evidence argues for the variable central spike being produced by a modest accretion event onto a central massive black hole (BH), with the accreted material having possibly being stripped from a star in a close fly-by with the BH. In this regard, one has to look at NGC 4552 as the faintest known AGN.

Type
IV. AGN Related Phenomena
Copyright
Copyright © Astronomical Society of the Pacific 1999 

References

Bertola, F., Cappellari, M., Burstein, D., Greggio, L., Renzini, A., di Serego Alighieri, S. 1995, Stellar Populations, ed. Gilmore, G. & van der Kruit, P. (Dordrecht: Kluwer), p. 445 CrossRefGoogle Scholar
Cappellari, M., Bertola, F., Burstein, D., Buson, L.M., Greggio, L. & Renzini, A.: UV Spikes in Bulge-Dominated Galaxies , 1998a, in: “STScI Workshop: How and When Do Bulges Form and Evolve?”, Carollo, C.M., Ferguson, H.C. & Wyse, R.F.G. (eds.), ASP Conf. Series, ASP, San Francisco Google Scholar
Cappellari, M., Renzini, A., Greggio, L., di Serego Alighieri, S., Buson, L.M., Burstein, D. & Bertola, F. 1998b, ApJ, submitted Google Scholar
Macchetto, F., Pastoriza, M., Caon, N., Sparks, W.B., Giavalisco, M., Bender, R., & Capaccioli, M. 1996, A&AS, 120, 463 Google Scholar
Magorrian, J., Tremaine, S., Richstone, D., Bender, R., Bower, G., Dressier, A., Faber, S.M., Gebhardt, K., et al. 1998, AJ, 115, 2285 CrossRefGoogle Scholar
Maoz, D., Filippenko, A.V., Ho, L.C., Macchetto, F.D., Rix, H.-W., & Schneider, D.P. 1996, ApJS, 107, 215 CrossRefGoogle Scholar
Renzini, A., Greggio, L., Di Serego Alighieri, S., Cappellari, M., Burstein, D., & Bertola, F. 1995, Nature, 378, 39 CrossRefGoogle Scholar
Van Dokkum, P.G. & Franx, M. 1995, AJ, 110, 2027 CrossRefGoogle Scholar
You have Access
1
Cited by

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.

A UV Flare at the Center of the Elliptical Galaxy NGC 4552
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.

A UV Flare at the Center of the Elliptical Galaxy NGC 4552
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.

A UV Flare at the Center of the Elliptical Galaxy NGC 4552
Available formats
×
×

Reply to: Submit a response

Please enter your response.

Your details

Please enter a valid email address.

Conflicting interests

Do you have any conflicting interests? *