The 6-GHz methanol multibeam maser catalogue - I. Galactic Centre region, longitudes 345° to 6°
| Autor: | Melvin Hoare, L. Quinn, M. R. Pestalozzi, Simon Ellingsen, Derek Ward-Thompson, Michael G. Burton, Adam Avison, R. J. Cohen, Maxim Voronkov, Chris Phillips, Naomi McClure-Griffiths, Antonio Chrysostomou, Philip J. Diamond, Andrew Walsh, Malcolm Gray, M. R. W. Masheder, Mark Thompson, Shari Breen, J. L. Caswell, Kate J. Brooks, J. Cox, D. Wong-McSweeney, Gary A. Fuller, J. A. Yates, James Green |
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| Rok vydání: | 2010 |
| Předmět: |
Physics
education.field_of_study Astrophysics::High Energy Astrophysical Phenomena Population Galactic Center Astronomy and Astrophysics Astrophysics::Cosmology and Extragalactic Astrophysics Astrophysics Galactic plane Latitude law.invention Thin disk Space and Planetary Science Bulge law Astrophysics::Solar and Stellar Astrophysics Maser education Longitude Astrophysics::Galaxy Astrophysics |
| Zdroj: | Monthly Notices of the Royal Astronomical Society. 404:1029-1060 |
| ISSN: | 1365-2966 0035-8711 |
| DOI: | 10.1111/j.1365-2966.2010.16339.x |
| Popis: | We have conducted a Galactic plane survey of methanol masers at 6668 MHz using a 7-beam receiver on the Parkes telescope. Here we present results from the first part, which provides sensitive unbiased coverage of a large region around the Galactic Centre. Details are given for 183 methanol maser sites in the longitude range 345$^{\circ}$ through the Galactic Centre to 6$^{\circ}$. Within 6$^{\circ}$ of the Centre, we found 88 maser sites, of which more than half (48) are new discoveries. The masers are confined to a narrow Galactic latitude range, indicative of many sources at the Galactic Centre distance and beyond, and confined to a thin disk population; there is no high latitude population that might be ascribed to the Galactic Bulge. Within 2$^{\circ}$ of the Galactic Centre the maser velocities all lie between -60 and +77 \kms, a range much smaller than the 540 \kms range observed in CO. Elsewhere, the maser with highest positive velocity (+107 \kms) occurs, surprisingly, near longitude 355$^{\circ}$ and is probably attributable to the Galactic bar. The maser with the most negative velocity (-127 \kms) is near longitude 346$^{\circ}$, within the longitude-velocity locus of the near side of the `3-kpc arm'. It has the most extreme velocity of a clear population of masers associated with the near and far sides of the 3-kpc arm. Closer to the Galactic Centre the maser space density is generally low, except within 0.25 kpc of the Centre itself, the `Galactic Centre Zone', where it is 50 times higher, which is hinted at by the longitude distribution, and confirmed by the unusual velocities. |
| Databáze: | OpenAIRE |
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