The Properties of the Radio-Selected 1 J[CLC]y[/CLC] Sample of BL Lacertae Objects

Rector, T. A.; Stocke, John T.

doi:10.1086/321179

Cited by 123 publications

(136 citation statements)

References 82 publications

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“…Due to crowding in right ascension (RA) around 11-12 h, we could only observe 42 of them; these were chosen according to their RA and Dec only, disregarding any previously available information on absorption systems. To consistently take into account all the 1 Jy sources of Rector & Stocke (2001) at z em > 0.8, we included the three northern sources which have published, reliable spectroscopic information on the presence or lack of strong Mg ii systems (Miller et al 1978;Stocke & Rector 1997;Cohen et al 2003).…”

Section: Target Selectionmentioning

confidence: 99%

“…Thus, there are 45 sources at 0.8 < z em 1.8 in our final sample of which ten BL Lacs from the 1 Jy sources of Rector & Stocke (2001). Our sample comprises 35 BL Lacs, 7 FSRQs A51, page 2 of 13 Rector & Stocke (2001).…”

Section: Target Selectionmentioning

confidence: 99%

“…Our sample comprises 35 BL Lacs, 7 FSRQs A51, page 2 of 13 Rector & Stocke (2001). PG In the BL Lac sample of Padovani & Giommi (1995) and not in RS.…”

Section: Target Selectionmentioning

confidence: 99%

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Incidence of Mg ii absorbers towards blazars and the GRB/QSO puzzle

Bergeron

Boissé

Ménard

2010

A&A

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In order to investigate the origin of the excess of strong Mg ii systems towards GRB afterglows as compared to QSO sightlines, we have measured the incidence of Mg ii absorbers towards a third class of objects: the blazars. This class includes the BL Lac object population for which a tentative excess of Mg ii systems had already been reported. We observed with FORS1 at the ESO-VLT 42 blazars with an emission redshift 0.8 < z em < 1.9, to which we added the three high z northern objects belonging to the 1 Jy BL Lac sample. We detect 32 Mg ii absorbers in the redshift range 0.35-1.45, leading to an excess in the incidence of Mg ii absorbers compared to that measured towards QSOs by a factor ∼2, detected at 3σ. The amplitude of the effect is similar to that found along GRB sightlines. Our analysis provides a new piece of evidence that the observed incidence of Mg ii absorbers might depend on the type of background source. In front of blazars, the excess is apparent for both "strong" (w r (2796) > 1.0 Å) and weaker (0.3 < w r (2796) < 1.0 Å) Mg ii systems. The dependence on velocity separation with respect to the background blazars indicates, at the ∼1.5σ level, a potential excess for β ≡ v/c ∼ 0.1. We show that biases involving dust extinction or gravitational amplification are not likely to notably affect the incidence of Mg ii systems towards blazars. Finally we discuss the physical conditions required for these absorbers to be gas entrained by the powerful blazar jets. More realistic numerical modelling of jet-ambient gas interaction is required to reach any firm conclusions as well as repeat observations at high spectral resolution of strong Mg ii absorbers towards blazars in both high and low states.

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Section: Target Selectionmentioning

confidence: 99%

Section: Target Selectionmentioning

confidence: 99%

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Incidence of Mg ii absorbers towards blazars and the GRB/QSO puzzle

Bergeron

Boissé

Ménard

2010

A&A

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“…Later spectroscopy (e.g. Stickel et al 1993;Falomo et al 1994;Rector & Stocke 2001) has confirmed the absorption system, but no emission features or host galaxy absorption lines have been detected and the redshift remains unknown. Optical imaging (Hutchings et al 1988;Abraham et al 1991;Stickel et al 1993;Falomo & Ulrich 2000;Scarpa et al 2000;Pursimo et al 2002) has also failed to detect the host galaxy.…”

Section: Introductionmentioning

confidence: 99%

Redshift constraints for RGB 0136+391 and PKS 0735+178 from deep optical imaging

Nilsson

Pursimo

Villforth

et al. 2012

A&A

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We present the results of deep I-band imaging of two BL Lacerate objects, RGB 0136+391 and PKS 0735+178, during an epoch when the optical nucleus was in a faint state in both targets. In PKS 0735+178 we find a significant excess over a point source, which, if fitted by the de Vaucouleurs model, corresponds to a galaxy with I = 18.64 ± 0.11 and r eff = 1.8 ± 0.4 arcsec. Interpreting this galaxy as the host galaxy of PKS 0735+178 we derive z = 0.45 ± 0.06 using the host galaxy as a "standard candle". We also discuss the immediate optical environment of PKS 0735+178 and the identity of the MgII absorber at z = 0.424. Despite of the optimally chosen epoch and deep imaging we find the surface brightness profile of RGB 0136+391 to be consistent with a point source. By determining a lower limit for the host galaxy brightness by simulations, we derive z > 0.40 for this target.

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“…Its redshift is highly uncertain since its spectrum is basically flat; Stickel et al (1993) derived a lower limit of z ≥ 0.2. A tentative value of z ≈ 0.63 was estimated (Rector & Stocke 2001) and then confirmed at z = 0.635 (Landoni et al 2012). This BLLac object, as most of its kind, shows variability at almost every wavelength range, from radio to optical bands (Pica et al 1988).…”

Section: Resultsmentioning

confidence: 86%

Optical flux behaviour of a sample ofFermiblazars

Marchesini

Andruchow

Cellone

et al. 2016

A&A

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Aims. We aim at investigating the time-behaviour of a sample of gamma-ray blazars. We present the results from a 13 monthlong optical photometry monitoring campaign of the blazars PKS 0048−097, PKS 0754+100, [HB89] 0827+243, PKS 0851+202, PKS 1253−055, PKS 1510−089, PKS 1749+096, PKS 2230+114 and PKS 2251+158. Methods. We analyse the variability of each object, focusing on different time-scales (long term, short term, and microvariability), in an attempt to achieve a statistical comparison of the results. Results. After applying a geometric model to explain the variability results, we found that it is possible that a slight change in the direction of the jet generates the variations detected in some objects during this campaign.

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The Properties of the Radio-Selected 1 J[CLC]y[/CLC] Sample of BL Lacertae Objects

Cited by 123 publications

References 82 publications

Incidence of Mg ii absorbers towards blazars and the GRB/QSO puzzle

Incidence of Mg ii absorbers towards blazars and the GRB/QSO puzzle

Redshift constraints for RGB 0136+391 and PKS 0735+178 from deep optical imaging

Optical flux behaviour of a sample ofFermiblazars

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