We determine the extinction curve in the zl=0.83 lens galaxy of the gravitational lens SBS 0909+532 from the wavelength dependence of the flux ratio between the...
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PublicaciónDetection of the 2175 Å Extinction Feature at z = 0.83
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PublicaciónDetection of very high energy gamma-ray emission from the gravitationally lensed blazar QSO B0218+357 with the MAGIC telescopes
Context. QSO B0218+357 is a gravitationally lensed blazar located at a redshift of 0.944. The gravitational lensing splits the emitted radiation into two...
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PublicaciónDetermination of the properties of the central engine in microlensed QSOs
We study a recently observed gravitational microlensing peak in the V-band light curve of Q2237+0305A using a relatively simple physical model, but one that is...
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PublicaciónDetermining the fraction of reddened quasars in COSMOS with multiple selection techniques from X-ray to radio wavelengths
The sub-population of quasars reddened by intrinsic or intervening clouds of dust are known to be underrepresented in optical quasar surveys. By defining a...
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PublicaciónDiscovery of a binary quasar at z = 1.76
We present the serendipitous discovery of a physical pair of quasars with estimated cosmological redshift z = 1.76. Long-slit spectroscopic observations of the...
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PublicaciónDiscovery of Very High Energy γ-Rays from 1ES 1011+496 at z = 0.212
We report on the discovery of very high energy (VHE) γ-ray emission from the BL Lacertae object 1ES 1011+496. The observation was triggered by an optical...
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PublicaciónDo the Most Massive Black Holes at z = 2 Grow via Major Mergers?
The most frequently proposed model for the origin of quasars holds that the high accretion rates seen in luminous active galactic nuclei (AGN) are primarily...
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PublicaciónDramatic emission line variations in QSO KAZ 102 and possible causes
We report optical spectroscopic observations of the radio-quiet quasar Kaz 102. We find impressive variations of the Hα emission line both in shape and...
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PublicaciónDust Reverberation Mapping in Distant Quasars from Optical and Mid-infrared Imaging Surveys
The size of the dust torus in active galactic nuclei (AGNs) and their high-luminosity counterparts, quasars, can be inferred from the time delay between UV...