[seminar] Astro Journal Club on 4 May

[Oskari Miettinen]

Dear all,

Our Astro Journal Club will be held on Wednesday at 3:00 pm (sharp) in the
seminar room F-201 of the Physics Department. This time we will discuss a
recent paper on galaxy-scale gravitational lens systems.

Presenter: Mladen Novak
Paper title: Galaxy-scale gravitational lens candidates from the Hyper
Suprime-Cam imaging survey and the Galaxy And Mass Assembly spectroscopic
survey
Authors: Chan, J. H. H., Suyu, S. H., More, A., et al.

Summary:
We present a list of galaxy-scale lens candidates including a highly
probable interacting galaxy-scale lens in the Hyper Suprime-Cam (HSC)
imaging survey. We combine HSC imaging with the blended-spectra catalog
from the Galaxy And Mass Assembly (GAMA) survey to identify lens
candidates, and use lens mass modeling to confirm the candidates. We find
46 matches between the HSC S14A-0b imaging data release and the GAMA
catalog. Ten of them are probable lens systems according to their
morphology and redshifts. There is one system with an interacting galaxy
pair, HSC J084928+000949, that has a valid mass model. We predict the
total mass enclosed by the Einstein radius of 0.72 arcsec (1.65 kpc) for
this new expected lens system to be 1e10.59 Msun. Using the photometry in
the grizy bands of the HSC survey and stellar population synthesis
modeling with a Salpeter stellar initial mass function, we estimate the
stellar mass within the Einstein radius to be 1e10.46 Msun. We thus find a
dark matter mass fraction within the Einstein radius of 25 percent.
Further spectroscopy or high-resolution imaging would allow confirmation
of the nature of these lens candidates. The particular system with the
interacting galaxy pair, if confirmed, would provide an opportunity to
study the interplay between dark matter and stars as galaxies build up
through hierarchical mergers.

Link to the paper: http://adsabs.harvard.edu/abs/2016arXiv160408215C

See you all on Wednesday!

Cheers,
Oskari