In:
Publications of the Astronomical Society of Japan, Oxford University Press (OUP), Vol. 56, No. 5 ( 2004-10-25), p. 765-802
Abstract:
We surveyed 401 color-selected IRAS sources in the galactic disk in the SiO $J = 1 \hbox{--} 0, v = 1$ and 2 maser lines at 43 GHz, resulting in 254 (239 new) detections. The observed sources lie mostly in a strip of the inner galactic disk with boundaries $-10^{\circ} & lt; l & lt; 40^{\circ}$ and $\vert b\vert & lt; 3^{\circ}$. This survey provides radial velocities of inner-disk stars for which optical measurements cannot be made due to interstellar extinction. The SiO $l \hbox{--} v$ diagram in the area $-10^{\circ} & lt; l & lt; 40^{\circ}$ exhibits fewer objects coincident with the molecular ring feature than does the OH 1612 MHz source $l \hbox{--} v$ map, indicating a slight difference of stellar type between SiO and OH emitting stars. After identifying all of the SiO detected sources in the 2MASS near-infrared catalog, we computed their luminosity distances based on the infrared fluxes. We then mapped these objects onto the first quadrant of the galactic plane. Combining the distances with the SiO radial velocities, we obtained a pattern speed for SiO maser sources, $\Omega_{\mathrm{P}} = 21 (\pm 13) \,\mathrm{km} \,\mathrm{s}^{-1} \,\mathrm{kpc}^{-1}$, between the distances 1 and 5.5 kpc, without the use of any dynamical models. The increase of the pattern speed toward the galactic center (up to $60 \,\mathrm{km} \,\mathrm{s}^{-1} \,\mathrm{kpc}^{-1}$ between the distances, 5.5 and 7 kpc) suggests the presence of two pattern speeds in the Galaxy.
Type of Medium:
Online Resource
ISSN:
0004-6264
,
2053-051X
DOI:
10.1093/pasj/56.5.765
Language:
English
Publisher:
Oxford University Press (OUP)
Publication Date:
2004
detail.hit.zdb_id:
2206640-8
detail.hit.zdb_id:
2083084-1
SSG:
16,12
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