Water Maser and Ammonia Survey toward IRAS Sources in the Galaxy I. H₂O Maser Data

We present H ₂ O maser data from a survey toward IRAS sources in the Galaxy with the Nobeyama 45 m telescope. This survey had a 1σ noise level as small as 0.24 Jy, resulting in one of the most sensitive water-maser surveys. The maximum distance of the masers to be detected by our survey is estimated to be 3 kpc for sources with Fν, 1\,kpc < 10 Jy and 10 kpc for those with 10 Jy ≤ Fν, 1\,kpc < 100 Jy, where Fν, 1\,kpc is the maser flux density converted at a distance of 1 kpc. For strong masers with Fν, 1\,kpc ≥ 100 Jy, our survey could detect all sources in the Galaxy. We carried out a total of 2229 observations toward 1563 sources and detected water-maser emission toward 222 sources. Our survey newly found masers from 75 of the 222 sources. The maser spectra of the new sources are shown in addition to the line parameters of all the detected sources. Furthermore, we discovered an extremely high-velocity component with VLSR = -146kms⁻¹ toward a well-known source, NGC 7538 IRS 11. For the three sources of NGC 1333 IRAS 4A/B, IRAS 05329$-$0512, and 06053$-$0622, we succeeded to spatially separate multiple-velocity components.