ARCSAT ID NUMBER: AS06

DESCRIPTIVE TITLE: Stromgren Photometry of Galactic Peripherys and 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 between April 17 and July 3, 2016

INSTRUMENT: SurveyCam

FILTERS: Stromgren uvby, 2" square

COMMENTS: remote observations

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. One 
observing run scheduled in November 2015 was cancelled (by D.B.) 
because of scheduling conflict. Q1 2016 run was successful,
but we did not get any clear night: all of them were partly 
or mostly cloudy. 

NOTE: I will be unavailable between April 10 and April 17,
and can observe any other time. 

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