Extended
HI Emission
Around the Pegasus Dwarf Galaxy
Project Leaders:
Noah Brosch and Lyle Hoffman
Institutions:
Wise Observatory and Lafayette College
Other Co-Authors:
Alexei Kniazev (SAAO)
Time frame:
2008
Description: (up to ~ 500 words)
The Pegasus dwarf galaxy (DDO 216) has received considerable attention
from HI observers
in the past, including ourselves (Hoffman et al. 1996, ApJS, 105, 269).
Recently, it has
been claimed that the HI extension evident in our major axis mapping
(Fig. 5x in Hoffman et al. 1996) and in synthesis mapping (Young et
al., 2003, ApJ, 592, 111)
is a result of ram pressure stripping by the intragroup medium of the
Local Group
(McConnachie et al. 2007, ApJL, 671, L33). If so, one might expect
diffuse extensions
of the neutral gas downwind (to the northwest), resolved out by the
synthesis mapping but
visible in the ALFALFA data. Indications of faint extensions of the
galaxy to the NW are apparent in SDSS data processed to select stars in
the Pegasus dwarf galaxy.
ALFALFA data for this region have been acquired but not yet processed
into a grid. Commensal GALFA data at higher velocity resolution should
also be available, and might clarify that the extended gas is
associated with the Pegasus dwarf rather than multiple gas clouds
around the galaxy, as originally proposed by Young et al.
We propose to undertake the processing of the data to Level I (all
drifts not done by
other members of ALFALFA) and into a standard grid, followed by source
extraction for the entire grid and the analysis of the results for DDO
216, with a publication containing the SDSS and HI results to be
submitted within a few months.
This page created and maintained by members of the
Cornell ExtraGalactic GroupLast modified: Wed 21 Nov. 2007
by Lyle
