The<i>Hubble Space Telescope</i>Survey of BL Lacertae Objects. I. Surface Brightness Profiles, Magnitudes, and Radii of Host Galaxies

Scarpa, Riccardo; Urry, C. Megan; Falomo, R.; Pesce, Joseph E.; Treves, A.

doi:10.1086/308618

Cited by 155 publications

(223 citation statements)

References 73 publications

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“…Any differences between our results and the P02 results should thus reflect differences in the analysis method. The third dataset comes from the HST study of Scarpa et al (2000a;hereafter SU00). All comparison sets have been analyzed with the same 1-dim analysis package, whereas we have used a 2-dim method.…”

Section: Comparison With Previous Resultsmentioning

confidence: 99%

“…Abraham et al 1991;Stickel et al 1993;Wurtz et al 1996;Falomo & Kotilainen 1999;Scarpa et al 2000a;Urry et al 2000;Pursimo et al 2002) have shown that BL Lacs lie in the nuclei of luminous (M R ∼ −23.7) and large (r eff ∼ 10 kpc) elliptical galaxies. Their bulk properties appear to be indistinguishable from those of the host galaxies of Fanaroff-Riley (FR) type I radio sources (Fanaroff & Riley 1974), supporting the unifying view that BL Lacs are FR I radio sources seen almost along the direction of the jet (Urry & Padovani 1995).…”

Section: Introductionmentioning

confidence: 99%

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R-band imaging of the host galaxies of RGB BL Lacertae objects

Nilsson

Pursimo

Heidt³

et al. 2003

A&A

124

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Abstract. We present optical R-band images of 100 BL Lacertae objects in the ROSAT-Green Bank (RGB) sample obtained at the Nordic Optical Telescope (NOT). For 62 objects we could not find any previously published images in the literature, of these 35 are new BL Lacs discovered during the RGB BL Lac survey. We were able to resolve the host galaxy in 62% of the objects. We analyze the host galaxies using a two-dimensional fitting procedure and tabulate the best-fit core magnitude and host galaxy parameters (magnitude, effective radius, ellipticity, position angle and shape parameter β) for each object. With two exceptions, all objects are better fit by a model representing an elliptical galaxy (β = 0.25) than by a disk galaxy model (β = 1.0). In the two exceptions the disk host fit is only marginally better than the elliptical host fit, however, and we do not find a single clear example of a disk-dominated host galaxy. The host galaxies have an average brightness M R = −23.9 ± 0.8 and average effective radius r eff = 13.2 ± 0.8 kpc. Their bulk properties are indistinguishable from normal elliptical and radio galaxies. The median β is 0.18, well below the value 0.25 that is normally used to describe ellipticals. However, the difference may be caused by a selection effect due to the dependence of β on host galaxy luminosity.

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Section: Comparison With Previous Resultsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

R-band imaging of the host galaxies of RGB BL Lacertae objects

Nilsson

Pursimo

Heidt³

et al. 2003

A&A

124

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“…We have also reported the core dominance (CD) parameter in the R band, i.e. the ratio between the nuclear intensity to that of the host galaxy, collected from the literature (Wurtz et al 1996;Scarpa et al 2000). It is apparent that the WDP is different for the various sources.…”

Section: Discussionmentioning

confidence: 99%

“…For objects observed in more than one night, the weighted average is given. c Ratio between nuclear and galactic flux in R band (Wurtz et al 1996;Scarpa et al 2000). d Magnetic field intensity in Gauss (Ghisellini et al 1998;Tagliaferri et al 2001).…”

Section: C 66amentioning

confidence: 99%

Multiband optical polarimetry of BL Lacertae objects with the Nordic Optical Telescope

Tommasi

Palazzi

Pian

et al. 2001

A&A

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Abstract. Optical polarization of seven selected BL Lac objects in UBV RI bands was studied with the Nordic Optical Telescope from December 10-14, 1999. Two of them, 3C 66A and PKS 0735+178, were monitored for 4 nights for a total integration time of 4.75 and 5.5 hours, respectively. Other objects (1 Jy 0138−097, H 0414+009, PKS 0823−223, OJ287 and BL Lac) were observed sparsely during the run. Apart from PKS 0823−223 (more polarized than observed in the past), the sources show levels of flux and polarization consistent with results at previous epochs. 3C 66A and PKS 0735+178 were intensively observed during December 11 and 12 and exhibited variability of polarization, both on internight and intranight time scales. Wavelength dependence of polarization has been investigated, as well as circular polarization. The results are discussed within the standard model for BL Lacs.

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“…Using the A λ versus λ relationship of Cardelli et al (1989) we found the extinction (in magnitudes) in the B, R, and I filters: A B = 0.53, A R = 0.30, and A I = 0.19. Finally, we converted the dereddened magnitudes into flux, without applying any correction for the contribution of the host galaxy, as it cannot be resolved even in deep HST images (Scarpa et al 2000). be observed in most of the S4 0954+658 light curves.…”

Section: Observations and Data Reductionmentioning

confidence: 99%

Multi-band optical micro-variability observations of the BL Lac object S4 0954+658

Papadakis¹,

Samaritakis²,

Boumis

et al. 2004

A&A

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Abstract.We have observed S4 0954+658 in the B, V, R and I bands for one night in March and two nights in April, 2001, and in the B and I bands for four nights in May, 2002. The observations resulted in almost evenly sampled light curves, 3−8 h long, with an average sampling interval of ∼5−15 min. Because of the dense sampling and the availability of light curves in more than one optical band we are able to study the intra-night flux and spectral variability of the source in detail. Significant observations were observed in all but one case. On average, the flux variability amplitude, on time scales of min/h, increases from ∼2−3% in the I, to ∼3.5−5.5% in the B band light curves. We do not detect any flares within the individual light curves. However, there is a possibility that the April 2001 and late May 2002 observations sample two flares which lasted longer than ∼1−3 days. The evidence is only suggestive though, due to the limited length of the present light curves with regard to the duration of the assumed flares. No spectral variations are detected during the April 2001 observations. The source flux rises and decays with the same rate, in all bands. This variability behaviour is typical of S4 0954+658, and is attributed to geometrical effects. However, significant spectral variations are observed in May 2002. We find that the spectrum hardens/softens as the flux increases/decreases, respectively. Furthermore, the "hardening" rate of the energy spectrum is faster than the rate at which the spectrum becomes "redder" as the flux decays. We also find evidence (although of low statistical significance) that the I band variations are delayed with respect to the B band variations. If the May 2002 observations sample a flaring event, these results suggest that the variations are caused by energetic processes which are associated with the particle cooling and the source light travel time scales.

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TheHubble Space TelescopeSurvey of BL Lacertae Objects. I. Surface Brightness Profiles, Magnitudes, and Radii of Host Galaxies

Cited by 155 publications

References 73 publications

R-band imaging of the host galaxies of RGB BL Lacertae objects

R-band imaging of the host galaxies of RGB BL Lacertae objects

Multiband optical polarimetry of BL Lacertae objects with the Nordic Optical Telescope

Multi-band optical micro-variability observations of the BL Lac object S4 0954+658

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