T. Mahoney

Tracing the long bar with red-clump giants

Context. Over the last decade a series of results have lent support to t he hypothesis of the existence of a long thin bar in the Milky Way with a half-length of 4.5 kpc and a position angle of around 45 ◦ . This is apparently a very different structure from the triaxial bulge of the Galaxy. Aims. In this paper, we analyse the stellar distribution in the inn er 4 kpc of the Galaxy to see if there is clear evidence for two triaxial or barlike structures, or whether there is only one. Methods. By using the red-clump population as a tracer of the structure of the inner Galaxy we determine the apparent morphology of the inner Galaxy. Star counts from 2MASS are used to provide additional support for this analysis. Results. We show that there are two very different large-scale triaxial structures coexisting in the in ner Galaxy: a long thin stellar bar constrained to the Galactic plane (|b| < 2 ◦ ) with a position angle of 43. ◦ 0±1. ◦ 8, and a distinct triaxial bulge that extends to at least |b| ≤ 7.5 ◦ with a position angle of 12. ◦ 6±3. ◦ 2. The scale height of the bar source distribution is around 100 pc, whereas for the bulge

The Long Bar in the Milky Way: Corroboration of an Old Hypothesis

Recent Galactic Legacy Infrared Mid-Plane Survey Extraordinaire data have further confirmed the hypothesis of the existence of an in-plane long bar different from the bulge of the Milky Way with the same characteristics as emphasized some years ago by our team. In this paper we present two new analyses that corroborate recent and earlier claims concerning the existence in our Galaxy of a long, flat bar with approximate dimensions of 7.8 kpc ? 1.2 kpc ? 0.2 kpc and a position angle of approximately 43?: (1) star counts with 2MASS All-Sky Data Release and Midcourse Space Experiment data, which give an excess in the plane region along 0? < l < 30? compared with -30? < l < 0? that cannot be due to the bulge, spiral arms, a ring, or extinction; and (2) new data on the distance of the long bar using the red clump method, together with recent observations of our own that are compared with our model and that are in agreement with the long-bar scenario.

Searching for the in-plane Galactic bar and ring in DENIS

New evidence for a long thin Galactic bar (in contradistinction to the bulge), as well as for the existence of the ring and the truncation of the inner disc, are sought in the DENIS survey. First, we examine DENIS and Two Micron Galactic Survey star counts for the characteristic signatures of an in-plane bar and ring. The star counts in the plane for

Inversion of stellar statistics equation for the Galactic bulge

30^\circ> l> -30^\circ

A Major Star Formation Region in the Receding Tip of the Stellar Galactic Bar

are shown to be highly asymmetric with considerably more sources at positive than at negative longitudes. At

A Major Star Formation Region in the Receding Tip of the Stellar Galactic Bar. II. Supplementary Information and Evidence that the Bar is not the Same Structure as the Triaxial Bulge Previously Reported

|b|\approx 1.5^\circ

Homogeneity of image quality at the Roque de los Muchachos Observatory

, however, the counts are nearly symmetric. Therefore, the asymmetry is not due to the disc, which is shown to have an inner truncation, or to the bulge, so there has to be another major component in the inner Galaxy that is causing the asymmetries. This component provides up to 50% of the detected sources in the plane between the bulge and

IR Star Counts in the Inner Disc

l=27^\circ

GTC site-testing campaign: meteorology

or

Search for star clustering: methodology and application to the Two Micron Galactic Survey

l=-14^\circ