Context.BL Lacertae objects have been the targets for numerous recent multiwavelength campaigns, continuum spectral variability studies, and theoretical spectral and variability modeling. A meaningful interpretation of the results of such studies requires a reliable knowledge of the objects' redshifts; however, the redshifts for many are still unknown or uncertain. Aims.Therefore, we hope to determine or constrain the redshifts of six BL Lac objects with unknown or poorly known redshifts. Methods.Observations were made of these objects with the MDM 2.4 m Hiltner telescope. Although no spectral features were detected, and thus no redshifts could be measured, lower redshift limits were assigned to the objects based on the e...
We present optical spectra with high signal-to-noise ratio of 10 BL Lac objects detected at GeV ener...
Context. The study of BL Lac objects (BLL) detected in gamma-rays gives insights on the acceleration...
We are carrying out a multi-purpose program of high signal to noise optical spectroscopy at medium...
Aims. Since no spectroscopic redshift is available for the remarkable BL Lacertae object (BL Lac) 1...
Aims. We aim to determine the redshift (or stringent lower limits) of a number of bright BL Lacs obj...
Aims.We present optical spectroscopy for a sample of BL Lac objects, to determine their redshift, t...
Aims: We present optical spectroscopy of a sample of BL Lac objects, to determine their redshift, to...
We report on 16 BL Lacertae objects that were proposed to be at z > 1. We present spectroscopic obse...
Aims. We attempt to determine the spectroscopic redshifts of bright BL Lac objects, which have prove...
We report results of a spectroscopic campaign carried out at the 10 m Gran Telescopio Canarias for a...
We report redshift measurements for 12 BL Lacertae objects from a program aimed at obtaining high si...
Abstract BL Lacertae (BL Lac) objects at high redshifts (z ≥ 2) are rarely detected. Through careful...
We present a sample of 723 optically selected BL Lac candidates from the Sloan Digital Sky Survey Da...
We present a sample of 347 BL Lacertae (BL Lac) candidates identified from 2600 deg^2 of the Sloan D...
Context. Observations of the γ-ray sky with Fermi led to significant advances towards understanding ...
We present optical spectra with high signal-to-noise ratio of 10 BL Lac objects detected at GeV ener...
Context. The study of BL Lac objects (BLL) detected in gamma-rays gives insights on the acceleration...
We are carrying out a multi-purpose program of high signal to noise optical spectroscopy at medium...
Aims. Since no spectroscopic redshift is available for the remarkable BL Lacertae object (BL Lac) 1...
Aims. We aim to determine the redshift (or stringent lower limits) of a number of bright BL Lacs obj...
Aims.We present optical spectroscopy for a sample of BL Lac objects, to determine their redshift, t...
Aims: We present optical spectroscopy of a sample of BL Lac objects, to determine their redshift, to...
We report on 16 BL Lacertae objects that were proposed to be at z > 1. We present spectroscopic obse...
Aims. We attempt to determine the spectroscopic redshifts of bright BL Lac objects, which have prove...
We report results of a spectroscopic campaign carried out at the 10 m Gran Telescopio Canarias for a...
We report redshift measurements for 12 BL Lacertae objects from a program aimed at obtaining high si...
Abstract BL Lacertae (BL Lac) objects at high redshifts (z ≥ 2) are rarely detected. Through careful...
We present a sample of 723 optically selected BL Lac candidates from the Sloan Digital Sky Survey Da...
We present a sample of 347 BL Lacertae (BL Lac) candidates identified from 2600 deg^2 of the Sloan D...
Context. Observations of the γ-ray sky with Fermi led to significant advances towards understanding ...
We present optical spectra with high signal-to-noise ratio of 10 BL Lac objects detected at GeV ener...
Context. The study of BL Lac objects (BLL) detected in gamma-rays gives insights on the acceleration...
We are carrying out a multi-purpose program of high signal to noise optical spectroscopy at medium...