SIMBAD references

1996A&A...309..419N - Astronomy and Astrophysics, volume 309, 419-430 (1996/5-2)

BL Lacertae objects in the ROSAT All-Sky Survey: new objects and comparison of different search techniques.

NASS P., BADE N., KOLLGAARD R.I., LAURENT-MUEHLEISEN S.A., REIMERS D. and VOGES W.

Abstract (from CDS):

We report the discovery of 34 BL Lac objects identified during the correlation of the ROSAT All-Sky Survey (RASS) with the Hamburg Quasar Survey (HQS). We find that most of the newly identified sources have high ratios of X-ray to optical flux, log(fX/fB)>1.3, and use this criterion as an efficient, radio-independent means for selecting candidate BL Lac objects. Combining these new sources with 43 previously known BL Lac objects in the ∼6000deg2 surveyed area, allowed us to construct a new sample complete down to fX(0.1-2.4keV)≃5.5x10–12ergs/cm2/s. Using this sample, we compare the efficiency and selection effects inherent in two different search techniques: The first characterized by the selection of high log(fX/fB)objects and second by selection of objects with particular X-ray/radio/optical colour indices. The logS-logN diagram of the sample is consistent with results found in previous X-ray surveys, although it shows indications of more X-ray faint BL Lacs than previously thought. We expect ∼200 additional BL Lac objects among the remaining high log(fX/fB) BL Lac candidates in the surveyed area.

Abstract Copyright:

Journal keyword(s): BL Lac objects: general - X-rays: galaxies - surveys

Nomenclature: Table 3: [NBK96] JHHMMm+DDMM N=34

Simbad objects: 79

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