We report the first detections of Blue Straggler Stars (BSS) in the bulge of the Milky Way galaxy. Proper motions from extensive space-based observations along a single sight-line allow us to separate a sufficiently clean and well-characterized bulge
sample that we are able to detect a small population of bulge objects in the region of the color-magnitude diagram commonly occupied young objects and blue strgglers. However, variability measurements of these objects clearly establish that a fraction of them are blue stragglers. Out of the 42 objects found in this region of the color-magnitude diagram, we estimate that at least 18 are genuine BSS. We normalize the BSS population by our estimate of the number of horizontal branch stars in the bulge in order to compare the bulge to other stellar systems. The BSS fraction is clearly discrepant from that found in stellar clusters. The blue straggler population of dwarf spheroidals remains a subject of debate; some authors claim an anticorrelation between the normalised blue straggler fraction and integrated light. If this trend is real, then the bulge may extend it by three orders of magnitude in mass. Conversely, we find that the genuinely young (~5Gy or younger) population in the bulge, must be at most 3.4% under the most conservative scenario for the BSS population.
We present stellar proper motions in the Galactic bulge from the Sagittarius Window Eclipsing Extrasolar Search (SWEEPS) project using ACS/WFC on HST. Proper motions are extracted for more than 180,000 objects, with >81,000 measured to accuracy bette
r than 0.3 mas/yr in both coordinates. We report several results based on these measurements: 1. Kinematic separation of bulge from disk allows a sample of >15,000 bulge objects to be extracted based on >6-sigma detections of proper motion, with <0.2% contamination from the disk. This includes the first detection of a candidate bulge Blue Straggler population. 2. Armed with a photometric distance modulus on a star by star basis, and using the large number of stars with high-quality proper motion measurements to overcome intrinsic scatter, we dissect the kinematic properties of the bulge as a function of distance along the line of sight. This allows us to extract the stellar circular speed curve from proper motions alone, which we compare with the circular speed curve obtained from radial velocities. 3. We trace the variation of the {l,b} velocity ellipse as a function of depth. 4. Finally, we use the density-weighted {l,b} proper motion ellipse produced from the tracer stars to assess the kinematic membership of the sixteen transiting planet candidates discovered in the Sagittarius Window; the kinematic distribution of the planet candidates is consistent with that of the disk and bulge stellar populations.
The Wide Angle Search for Planets (WASP) photometrically surveys a large number of nearby stars to uncover candidate extrasolar planet systems by virtue of small-amplitude lightcurve dips on a < 5-day timescale typical of the ``Hot-Jupiters. Observat
ions with the SuperWASP-North instrument between April and September 2004 produced a rich photometric dataset of some 1.3 billion datapoints from 6.7 million stars. Our custom-built data acquisition and processing system produces ~0.02 mag photometric precision at V=13. We present the transit-candidates in the 03h-06h RA range. Of 141,895 lightcurves with sufficient sampling to provide adequate coverage, 2688 show statistically significant transit-like periodicities. Of these, 44 pass visual inspection of the lightcurve, of which 24 are removed through a set of cuts on the statistical significance of artefacts. All but 4 of the remaining 20 objects are removed when prior information at higher spatial-resolution from existing catalogues is taken into account. Of the four candidates remaining, one is considered a good candidate for follow-up observations with three further second-priority targets. We provide detailed information on these candidates, as well as a selection of the false-positives and astrophysical false-alarms that were eliminated, and discuss briefly the impact of sampling on our results.
