The host galaxy/AGN connection in nearby early-type galaxies - Is there a miniature radio-galaxy in every "core" galaxy?

被引:85
作者
Balmaverde, B
Capetti, A
机构
[1] Univ Turin, I-10125 Turin, Italy
[2] Osserv Astron Torino, INAF, I-10025 Pino Torinese, Italy
来源
ASTRONOMY & ASTROPHYSICS | 2006年 / 447卷 / 01期
关键词
galaxies : active; galaxies : bulges; galaxies : nuclei; galaxies : elliptical and lenticular; cD; galaxies : jets; galaxies : BL Lacertae objects : general;
D O I
10.1051/0004-6361:20054031
中图分类号
P1 [天文学];
学科分类号
0704 ;
摘要
This is the second of a series of three papers exploring the connection between the multiwavelength properties of AGN in nearby early-type galaxies and the characteristics of their hosts. We selected two samples with 5 GHz VLA radio flux measurements down to 1 mJy, reaching levels of radio luminosity as low as 10(36) erg s(-1). In Paper I we presented a study of the surface brightness profiles for the 65 objects with available archival HST images out of the 11(6) radio-detected galaxies. We classified early-type galaxies into "core" and "power-law" galaxies, discriminating on the basis of the slope of their nuclear brightness profiles, following the Nukers scheme. Here we focus on the 29 core galaxies (hereafter CoreG). We used HST and Chandra data to isolate their optical and X-ray nuclear emission. The CoreG invariably host radio-loud nuclei, with an average radio-loudness parameter of Log R = L-5 (GHz)/L-B similar to 3.6. The optical and X-ray nuclear luminosities correlate with the radio-core power, smoothly extending the analogous correlations already found for low luminosity radio-galaxies (LLRG) toward even lower power, by a factor of similar to 1000, covering a combined range of 6 orders of magnitude. This supports the interpretation of a common non-thermal origin of the nuclear emission also for CoreG. The luminosities of the nuclear sources, most likely dominated by jet emission, set firm upper limits, as low as L/L-Edd similar to 10(-9) in both the optical and X-ray band, on any emission from the accretion process. The similarity of CoreG and LLRG when considering the distributions host galaxies luminosities and black hole masses, as well as of the surface brightness profiles, indicates that they are drawn from the same population of early-type galaxies. LLRG represent only the tip of the iceberg associated with (relatively) high activity levels, with CoreG forming the bulk of the population. We do not find any relationship between radio-power and black hole mass. A minimum black hole mass of M-BH = 10(8) M-circle dot is apparently associated with the radio-loud nuclei in both CoreG and LLRG, but this effect must be tested on a sample of less luminous galaxies, likely to host smaller black holes. In the unifying model for BL Lacs and radio-galaxies, CoreG likely represent the counterparts of the large population of low luminosity BL Lac now emerging from the surveys at low radio flux limits. This suggests the presence of relativistic jets also in these quasi-quiescent early-type "core" galaxies.
引用
收藏
页码:97 / U101
页数:19
相关论文
共 85 条
[71]   A joint mid-infrared spectroscopic and X-ray imaging investigation of LINER galaxies [J].
Satyapal, S ;
Sambruna, RM ;
Dudik, RP .
ASTRONOMY & ASTROPHYSICS, 2004, 414 (03) :825-838
[72]   The Hubble Space Telescope survey of BL lacertae objects.: I.: Surface brightness profiles, magnitudes, and radii of host galaxies [J].
Scarpa, R ;
Urry, CM ;
Falomo, R ;
Pesce, JE ;
Treves, A .
ASTROPHYSICAL JOURNAL, 2000, 532 (02) :740-815
[74]  
Sersic J. L., 1968, Atlas de Galaxias Australes
[75]   PARSEC-SCALE RADIO CORES IN EARLY-TYPE GALAXIES [J].
SLEE, OB ;
SADLER, EM ;
REYNOLDS, JE ;
EKERS, RD .
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY, 1994, 269 (04) :928-946
[76]   Soft X-ray sources at the centers of the elliptical galaxies NGC 4472 and NGC 4649 [J].
Soldatenkov, DA ;
Vikhlinin, AA ;
Pavlinsky, MN .
ASTRONOMY LETTERS-A JOURNAL OF ASTRONOMY AND SPACE ASTROPHYSICS, 2003, 29 (05) :298-303
[77]   THE COMPLETE SAMPLE OF 1 JANSKY BL LACERTAE OBJECTS .1. SUMMARY PROPERTIES [J].
STICKEL, M ;
PADOVANI, P ;
URRY, CM ;
FRIED, JW ;
KUHR, H .
ASTROPHYSICAL JOURNAL, 1991, 374 (02) :431-439
[78]   Chandra snapshot observations of low-luminosity active galactic nuclei with a compact radio source [J].
Terashima, Y ;
Wilson, AS .
ASTROPHYSICAL JOURNAL, 2003, 583 (01) :145-158
[79]   The slope of the black hole mass versus velocity dispersion correlation [J].
Tremaine, S ;
Gebhardt, K ;
Bender, R ;
Bower, G ;
Dressler, A ;
Faber, SM ;
Filippenko, AV ;
Green, R ;
Grillmair, C ;
Ho, LC ;
Kormendy, J ;
Lauer, TR ;
Magorrian, J ;
Pinkney, J ;
Richstone, D .
ASTROPHYSICAL JOURNAL, 2002, 574 (02) :740-753
[80]   The peculiar small-scale X-ray morphology of NGC 5846 observed with Chandra [J].
Trinchieri, G ;
Goudfrooij, P .
ASTRONOMY & ASTROPHYSICS, 2002, 386 (02) :472-486