Data from the GBT HI Survey Around M31

Spencer Wolfe, D.J. Pisano, Jay Lockman, Stacy McGaugh, and Ed Shaya

S. Wolfe PhD Thesis (WVU, 2014)

The final results of our survey around M31, both between M31 and M33 and single deep pointings to the northwest of M31, are reported in S. Wolfe's PhD thesis as Chapter 4. Other chapters discuss the mapping technique used, the initial survey results, and a study of the high and intermediate velocity gas seen by GASS. The thesis is available here.

GBT Memo

We describe our observing and reduction techniques in the following GBT memo. Also included is the GBTIDL code we use for our data reduction: HIREDUCE.pro.

Conference Presentations

Wolfe et al. 2014
Lockman & Wolfe 2012 presented at the HI in Galaxies meeting in Green Bank, WV.
Wolfe et al. 2012

Our Survey around M31

The above image shows the regions we have mapped around M31 (to the northwest) and M33 (to the southeast) overlaid on the Braun & Thilker (2004) total HI intensity map from their WSRT total power survey around M31. The contours are at log N(HI)=17.0, 17.3, 17.7, 18.0, etc. up to log N(HI)=20.7. The "x" and "+" signs indicate where we did deep single pointings (as part of project GBT12A-266). Plus signs indicate detections of HI associated with M31, while crosses indicate non-detections. Typical pointings had total integration times (on+off) of about 76 minutes.

Initial M31 Survey

As part of project GBT11B-51, Wolfe et al. (2013) presented the first 250 hours of our 400 hour survey of a 12 square degree region of the M31-M33 HI filament. The data cube from this paper is available for download here

A movie illustrating how these data compare to the original Braun & Thilker (2004) survey is available here.

Full 400hr Survey of GBT11B-051 Region

Below are the total HI intensity (moment 0; left) and HI velocity field (moment 1; right) maps from the full 400 hour survey of the GBT11B-051 region (Wolfe 2014).

These new maps show that the clouds continue to grow to lower column densities and reveal more details about their internal structure. A paper is currently in preparation on these data and will appear here once it has been submitted by mid-February 2015. Data on the other two mapped regions are currently being reduced and will appear here as soon they are completed and ready for publication.

Last Updated: July 10, 2015, DJP