ARCSAT ID NUMBER: AS06

DESCRIPTIVE TITLE: Stromgren Photometry of Galactic Streams

PI: Dmitry Bizyaev

OBSERVER(S): Dmitry Bizyaev

UNCERTIFIED/UNTRAINED OBSERVERS: N/A

COLLABORATORS:

CONTACT INFORMATION: dmbiz@apo.nmsu.edu

TIME REQUESTED: 1 week in the dark time.

INSTRUMENT: SurveyCam

FILTERS: Stromgren uvby, 2" square

COMMENTS: remote observations are expected

BRIEF SCIENCE JUSTIFICATION:
Last decade numerous faint structures at the periphery of regular
galaxies, as arcs, tails, or streams, have been discovered (see e.g.
Martinez-Delgado et al., 2010). We are still far from complete
understanding of the nature of these structures. Studying ages and
metallicities help constraining possible progenitors of the faint
structures. Since the periphery structures are too faint for good
spectroscopy, they have been observed in the broad-band filters.
The broad-band photometry is used for observing the faint structures,
but it does not allow to break the age-metallicity degeneracy
efficiently.

I propose to perform Stromgren photometry of a sample of regular
galaxies that have confirmed faint structures as arcs, streams and tails.
The standard Stromgren set is available at APO. The SyrveyCam has the
advantage of large field of view, which will allow to encompass all
extended structures (typically up to 10 arcmin in the sky plane) and
to provide more field for correct background subtraction.
The combination of uvby filters will allow to apply standard technique
for figuring out ages and metallicities for the stellar population at the
periphery since there is a very little or no emission detected from
there, the stellar population is essentially old, and the relatively
nearby galaxies will not require redshift-corrected filters. I will look for
the distribution of the stellar population parameters across the structures
and at the relationship of them to those of the edges of the parent
galaxies. I will start with two confirmed large galaxies: NGC 4216 and
NGC 4651, and then incorporate more from the sample of Martinez-Delgado.
Finally, will observe edge-on galaxies with faint structure observed by
SDSS and listed by Bizyaev et al. (2014).  We have got two clear nights
in October 2014, and 3 mostly clear nights in February 2015 for this
project.


Martinez-Delgado, D., Gabany, R. J., Crawford, K., et al.,
2010, AJ, 140, 962

Bizyaev, D., Kautsch, S., Mosenkov, A., et al. 2014, ApJ, 787, 24