Publications de Alexander Patrick Eigenbrod

Spectroscopy of extended Ly alpha envelopes around z=4.5 quasars

Pierre North, Alexander Patrick Eigenbrod, Frédéric Courbin

What are the frequency, shape, kinematics, and luminosity of Ly alpha envelopes surrounding radio-quiet quasars at high redshift, and is the luminosity of these envelopes related to that of the quasar or not? As a first step towards answering these questio ...

2012

Zooming into the broad line region of the gravitationally lensed quasar QSO 2237+0305 equivalent to the Einstein Cross III. Determination of the size and structure of the C-IV and C-III] emitting regions using microlensing

Georges Meylan, Alexander Patrick Eigenbrod, Frédéric Courbin, Rudiger Schmidt

Aims. We aim to use microlensing taking place in the lensed quasar QSO 2237+0305 to study the structure of the broad line region (BLR) and measure the size of the region emitting the C-IV and C-III] lines. ...

2011

Redshifts and lens profile for the double quasar QJ 0158-4325

Alexander Patrick Eigenbrod, Jean-Paul Richard Kneib

Aims. We report on the redshift of the lensing galaxy and of the quasar QJ 0158-4325 and on the lens model of the system. ...

2009

Deep optical spectroscopy of extended Ly alpha emission around three radio-quiet z=4.5 quasars

Pierre North, Alexander Patrick Eigenbrod, Frédéric Courbin

We report the first results of a spectroscopic search for Ly alpha envelopes around three z similar to 4.5 radio-quiet quasars. Our observational strategy adopts the FORS2 spectrograph mounted to the UT1 of the Very Large Telescope (VLT) in the multi-slit ...

2008

Microlensing variability in the gravitationally lensed quasar QSO 2237+0305 equivalent to the Einstein Cross - I. Spectrophotometric monitoring with the VLT

Georges Meylan, Alexander Patrick Eigenbrod, Frédéric Courbin

We present the results of the first long-term (2.2 years) spectroscopic monitoring of a gravitationally lensed quasar, namely the Einstein Cross QSO 2237+0305. The goal of this paper is to present the observational facts to be compared in follow-up papers ...

2008

Microlensing variability in the gravitationally lensed quasar QSO 2237+0305 equivalent to the Einstein Cross II. Energy profile of the accretion disk

Georges Meylan, Alexander Patrick Eigenbrod, Frédéric Courbin

We present the continuation of our long-term spectroscopic monitoring of the gravitationally lensed quasar QSO 2237 + 0305. We investigate the chromatic variations observed in the UV/optical continuum of both quasar images A and B, and compare them with nu ...

2008

Astrophysical applications of gravitationally lensed quasars : from dark matter halos to the structure of quasar accretion disks

Alexander Patrick Eigenbrod

Gravitational lensing describes how light is deflected as it passes in the vicinity of a mass distribution. The amplitude of the deflection is proportional to the mass of the deflector, called "gravitational lens", and is generally weak, even for large mas ...

EPFL2008

An exploratory search for z greater than or similar to 6 quasars in the ukidss early data release

Georges Meylan, Alexander Patrick Eigenbrod, Frédéric Courbin

We conducted an exploratory search for quasars at z similar to 6-8, using the Early Data Release (EDR) from the United Kingdom Infrared Deep Sky Survey (UKIDSS) cross-matched to panoramic optical imagery. High-redshift quasar candidates are chosen using mu ...

2008

A sharp look at the gravitationally lensed quasar SDSS J0806+2006 with laser guide star adaptive optics at the VLT

Georges Meylan, Alexander Patrick Eigenbrod, Frédéric Courbin

We present the first VLT near-IR observations of a gravitationally lensed quasar, using adaptive optics and laser guide star. These observations can be considered as a test bench for future systematic observations of lensed quasars with adaptive optics, ev ...

2008