2007A&A...476..723H


C.D.S. - SIMBAD4 rel 1.7 - 2020.07.04CEST20:26:52

2007A&A...476..723H - Astronomy and Astrophysics, volume 476, 723-734 (2007/12-3)

The stellar content of low redshift BL Lacertae host galaxies from multicolour imaging.

HYVOENEN T., KOTILAINEN J.K., FALOMO R., OERNDAHL E. and PURSIMO T.

Abstract (from CDS):

We present B-band imaging of 18 low redshift (z≤0.3) BL Lac objects for which their host galaxies were previously resolved in the R-band and the near-infrared H-band. For a subset of the objects, U- and V-band imaging also is presented. These multiwavelength data are used to investigate the blue-red-near-infrared colours and the colour gradients of the host galaxies of BL Lacs in comparison with other elliptical galaxies with and without nuclear activity. For all the BL Lacs observed in the B- and V-bands, and all objects at z<0.15 in the U-band, the host galaxy is clearly resolved. In all cases galaxies are well represented by an elliptical model, with average absolute magnitude MB=-21.6±0.7 and average scale length Re=7.6±3.2kpc. BL Lac host galaxies are therefore luminous (massive) elliptical galaxies, in agreement with previous studies in other bands. The best-fit B-band Kormendy relation of (µe=3.3logRe(kpc)+18.4mag/arcsec2) is in reasonable agreement with that obtained for normal ellipticals and radio galaxies. This structural and dynamical similarity indicates that all massive elliptical galaxies can experience nuclear activity without significant perturbation of their global structure. The distributions of the integrated blue/near-infrared colour (with average B-H=3.5±0.5) and colour gradient (with average Δ(B-R)/Δ(logr)=-0.14±0.75) of the BL Lac hosts are much wider than those for normal ellipticals, and most BL Lac objects have bluer hosts and/or steeper colour gradients than those in normal ellipticals. The blue colours are likely caused by a young stellar population component, and indicates a link between star formation caused by an interaction/merging event and the onset of the nuclear activity. This result is corroborated by stellar population modelling, indicating a presence of young/intermediate age populations in the majority of the sample, in agreement with low redshift quasar hosts. The lack of strong signs of interaction may require a significant time delay between the event with associated star formation episodes and the start of the nuclear activity.

Abstract Copyright:

Journal keyword(s): galaxies: active - galaxies: BL Lacertae objects: general - galaxies: interactions - galaxies: nuclei - galaxies: photometry - galaxies: structure

CDS comments: 1H 0706+591 = QSO B0706+591.

Simbad objects: 21

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Number of rows : 21

N Identifier Otype ICRS (J2000)
RA
ICRS (J2000)
DEC
Mag U Mag B Mag V Mag R Mag I Sp type #ref
1850 - 2020
#notes
1 QSO B0229+200 BLL 02 32 48.6154943841 +20 17 17.493345304   18.0 18.00     ~ 258 3
2 QSO B0521-365 BLL 05 22 57.9839686440 -36 27 30.847737786   15.26 14.62 14.48   ~ 711 2
3 QSO B0548-322 BLL 05 50 40.5706739558 -32 16 16.488658537   16.07 15.5     ~ 365 1
4 6C 070609+591309 BLL 07 10 30.0681446132 +59 08 20.369016804   17.38 16.52 15.1   ~ 181 2
5 Mrk 421 BLL 11 04 27.3139210166 +38 12 31.798324828   13.50 12.90 8.31   ~ 2381 1
6 6C 113337+702604 BLL 11 36 26.4084430 +70 09 27.307497   15.16 14.49 10.51   ~ 314 1
7 QSO B1212+078 BLL 12 15 10.9769954937 +07 32 04.674253273     16.0 14.8   ~ 77 1
8 NAME Vir I ClG 12 26 32.1 +12 43 24   10.00 8.49     ~ 5824 0
9 QSO B1229+6430 BLL 12 31 31.3953946380 +64 14 18.288194641   18.36 17.62 14.3   ~ 121 2
10 QSO B1255+244 BLL 12 57 31.9330234281 +24 12 40.168674935     15.4 15.7   ~ 70 0
11 ACO 1656 ClG 12 59 48.7 +27 58 50           ~ 4208 2
12 6C 141804+543700 BLL 14 19 46.5976435439 +54 23 14.787308481   16.17 15.65 14.16   ~ 537 1
13 QSO B1426+428 BLL 14 28 32.6090831425 +42 40 21.050020627   16.95 16.45 14.4   ~ 455 2
14 QSO B1440+122 BLL 14 42 48.276582 +12 00 40.37487   18.34 17.63 15.2   ~ 136 3
15 QSO B1514-24 BLL 15 17 41.8135246339 -24 22 19.482167214   15.13 14.00 13.95   ~ 643 3
16 QSO B1552+20 BLL 15 54 24.1302300084 +20 11 25.402710408     17.70     ~ 85 0
17 4C 39.49 BLL 16 53 52.21668494 +39 45 36.6089458 14.09 14.15 13.29 8.26   ~ 1912 2
18 6C 172704+501607 BLL 17 28 18.6239898055 +50 13 10.472390025   16.55 15.97 12.95   ~ 320 1
19 3C 371 BLL 18 06 50.6803567107 +69 49 28.108152993   14.77 14.22 11.39   ~ 795 2
20 QSO B2005-489 BLL 20 09 25.3910622923 -48 49 53.722146927   15.75 12.81 11.41   ~ 510 2
21 NAME BL Lac BLL 22 02 43.2913773726 +42 16 39.978417860   15.66 14.72     ~ 2006 1

    Equat.    Gal    SGal    Ecl

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2020.07.04-20:26:52

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