Misc,
From Exoplanets to Quasars: Detection of Potential Damped Lyman Alpha Absorbing Galaxies Using Angular Differential Imaging
(2016)cite arxiv:1609.00384.
Abstract
The advantages of angular differential imaging (ADI) has been previously
untested in imaging the host galaxies of damped Lyman alpha (DLA) systems. In
this pilot study, we present the first application of ADI to directly imaging
the host galaxy of the DLA seen towards the quasar J1431+3952. K-band imaging
of the field surrounding J1431+3952 was obtained on the Gemini North telescope
with the adaptive optics system and a laser guide star. We computed a
sensitivity curve that demonstrates the sensitivity of our observations as a
function of K-band magnitude, impact parameter and DLA angular size. For an
impact parameter of 0.5" (3.4 kpc at the redshift of the absorber) our mass
sensitivity is log (M_star/M_sun) ~ 9.2 and drops to ~ 9.0 at separations
beyond ~ 6 kpc for the smallest size model galaxy. Three candidate galaxies are
identified within 5". Stellar masses were computed from the K-band photometry
yielding values of log (M_star/M_sun) ~ 9.9, 9.7 and 11.1 respectively. The
likely identification of the absorbing galaxy is discussed, and we conclude
that the galaxy with the largest impact parameter and highest stellar mass is
unlikely to be the host, based on its inconsistency with the N(HI) impact
parameter relation and inconsistent photometric redshift. Whilst we cannot
distinguish between the remaining two candidates as the DLA host, we note that
despite the low spin temperature and relatively high metallicity of the DLA,
the host does not appear to be a particularly luminous (high mass) galaxy.
