- ID:
- ivo://CDS.VizieR/J/PASJ/59/1185
- Title:
- Water maser in galactic IRAS sources
- Short Name:
- J/PASJ/59/1185
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present H_2_O maser data from a survey toward IRAS sources in the Galaxy with the Nobeyama 45m telescope. This survey had a 1{sigma} noise level as small as 0.24Jy, 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 3kpc for sources with F_nu,1kpc_<10Jy and 10kpc for those with 10Jy<=F_nu,1kpc_<100Jy, where F_nu,1kpc_ is the maser flux density converted at a distance of 1kpc. For strong masers with F_nu,1kpc_>=100Jy, 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.
Number of results to display per page
Search Results
- ID:
- ivo://CDS.VizieR/J/ApJ/769/48
- Title:
- Water maser in Orion-KL with Herschel
- Short Name:
- J/ApJ/769/48
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Using the Herschel Space Observatory's Heterodyne Instrument for the Far-Infrared, we have performed mapping observations of the 620.701GHz 5_32_-4_41_ transition of ortho-H_2_O within a ~1.5'x1.5' region encompassing the Kleinmann-Low nebula in Orion (Orion-KL), and pointed observations of that transition toward the Orion South condensation and the W49N region of high-mass star formation. Using the Effelsberg 100m radio telescope, we obtained ancillary observations of the 22.23508GHz 6_16_-5_23_ water maser transition; in the case of Orion-KL, the 621GHz and 22GHz observations were carried out within 10days of each other. The 621GHz water line emission shows clear evidence for strong maser amplification in all three sources, exhibiting narrow (~1km/s FWHM) emission features that are coincident (kinematically and/or spatially) with observed 22GHz features. Moreover, in the case of W49N --for which observations were available at three epochs spanning a 2yr period-- the spectra exhibited variability. The observed 621GHz/22GHz line ratios are consistent with a maser pumping model in which the population inversions arise from the combined effects of collisional excitation and spontaneous radiative decay, and the inferred physical conditions can plausibly arise in gas heated by either dissociative or non-dissociative shocks. The collisional excitation model also predicts that the 22GHz population inversion will be quenched at higher densities than that of the 621GHz transition, providing a natural explanation for the observational fact that 22GHz maser emission appears to be a necessary but insufficient condition for 621GHz maser emission.
- ID:
- ivo://CDS.VizieR/J/ApJ/651/L125
- Title:
- Water masers associated with IR dark cloud cores
- Short Name:
- J/ApJ/651/L125
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present a survey of the 6_16_-5_23_ H_2_O maser transition toward a sample of 140 compact cores in infrared dark clouds using the Very Large Array. Strong (>1Jy) H_2_O maser emission was found associated with 17 cores, indicative of star formation in these cores. We infer that the cores with H2O masers have embedded protostars. Cores associated with maser emission have masses of 12 to 2x10^3^M_{sun}_, similar to the mass range in the entire sample. The H_2_O maser detection rate (12%) toward the compact, cold cores is much lower than that toward high-mass protostellar objects and ultracompact H ii regions. The detection rate of H_2_O masers is significantly higher for higher mass cores than for lower mass cores. We suggest that some of the most massive infrared dark cloud cores without H_2_O maser emission are at an evolutionary stage earlier than the protostellar phases. They are prime candidates for high-mass starless cores.
- ID:
- ivo://CDS.VizieR/J/ApJ/826/136
- Title:
- Water masers in M31. II. Multiwavelength data
- Short Name:
- J/ApJ/826/136
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present a comparative multiwavelength analysis of water-maser-emitting regions and non-maser-emitting luminous 24{mu}m star-forming regions in the Andromeda Galaxy (M31) to identify the sites most likely to produce luminous water masers useful for astrometry and proper motion studies. Included in the analysis are Spitzer 24{mu}m photometry, Herschel 70 and 160{mu}m photometry, H{alpha} emission, dust temperature, and star-formation rate. We find significant differences between the maser-emitting and non-maser-emitting regions: water-maser-emitting regions tend to be more infrared-luminous and show higher star-formation rates. The five water masers in M31 are consistent with being analogs of water masers in Galactic star-forming regions and represent the high-luminosity tail of a larger (and as yet undetected) population. Most regions likely to produce water masers bright enough for proper motion measurements using current facilities have already been surveyed, but we suggest three ways to detect additional water masers in M31: (1) reobserve the most luminous mid- or far-infrared sources with higher sensitivity than was used in the Green Bank Telescope survey; (2) observe early-stage star-forming regions selected by millimeter continuum that have not already been selected by their 24{mu}m emission, and (3) reobserve the most luminous mid- or far-infrared sources and rely on maser variability for new detections.
- ID:
- ivo://CDS.VizieR/J/ApJ/826/24
- Title:
- Water masers in M31. I. Recombination lines
- Short Name:
- J/ApJ/826/24
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We report the results of a Green Bank Telescope survey for water masers, ammonia (1,1) and (2,2), and the H66{alpha} recombination line toward 506 luminous compact 24{mu}m emitting regions in the Andromeda Galaxy (M31). We include the 206 sources observed in the Darling water maser survey for completeness. The survey was sensitive enough to detect any maser useful for ~10{mu}as/yr astrometry. No new water masers, ammonia lines, or H66{alpha} recombination lines were detected individually or in spectral stacks reaching rms noise levels of ~3mJy and ~0.2mJy, respectively, in 3.1-3.3km/s channels. The lack of detections in individual spectra and in the spectral stacks is consistent with Galactic extrapolations. Contrary to previous assertions, there do not seem to be any additional bright water masers to be found in M31. The strong variability of water masers may enable new maser detections in the future, but variability may also limit the astrometric utility of known (or future) masers because flaring masers must also fade.
23326. Water masers in Orion
- ID:
- ivo://CDS.VizieR/J/ApJ/493/940
- Title:
- Water masers in Orion
- Short Name:
- J/ApJ/493/940
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Measurements of the 6_16_ -> 5_23_ line of H_2_O at 1.3cm in the Orion region of star formation are reported. With a spatial resolution of ~0.1", H_2_O maser emission was detected in two regions: Orion BN/KL and Orion S. The well-known masers in the BN/KL region are distributed in a 30"x30" area. The "shell" masers, within the BN/KL region, are distributed in a 2" by 0.5" strip centered on radio source I and are offset from IRc2.
23327. Water maser survey
- ID:
- ivo://CDS.VizieR/J/AJ/132/1322
- Title:
- Water maser survey
- Short Name:
- J/AJ/132/1322
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We report on the most sensitive water maser survey toward Bok globules to date, performed using NASA's 70m antenna at Robledo de Chavela (Spain). We observed 207 positions within the Clemens and Barvainis catalog with a higher probability of harboring a young star, using as selection criteria the presence of radio continuum emission (from submillimeter to centimeter wavelengths), geometric centers of molecular outflows, peaks in maps of high-density gas tracers (NH3 or CS), and IRAS point sources. We have obtained seven maser detections, six of which (in CB 34, CB 54, CB 65, CB 101, CB 199, and CB 232) are reported for the first time here. Most of the water masers we detected are likely to be associated with young stellar objects (YSOs), except for CB 101 (probably an evolved object) and CB 65 (uncertain nature). The water maser in CB 199 shows a relatively high shift (30km/s) of its velocity centroid with respect to the cloud velocity, which is unusual for low-mass YSOs. We speculate that high-velocity masers in this kind of object could be related to episodes of energetic mass loss in close binaries. Alternatively, the maser in CB 199 could be pumped by a protoplanetary or a young planetary nebula. CB 232 is the smallest Bok globule (0.6pc) known to be associated with water maser emission, although it would be superseded by the cases of CB 65 (0.3pc) and CB 199 (0.5pc) if their association with YSOs is confirmed. All our selection criteria have statistically compatible detection rates, except for IRAS sources, which tend to be somewhat worse predictors for the presence of maser emission.
- ID:
- ivo://CDS.VizieR/J/PASJ/53/517
- Title:
- Water maser survey of late-type stars
- Short Name:
- J/PASJ/53/517
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- This paper presents new results of a water maser survey of late-type stellar objects at 22.235GHz with the Kashima 34-m radio telescope. We have detected 179 out of 643 observed sources, including 32 new detections. The sources were selected in terms of the IRAS flux density and colors of late-type stars, involving optically observable Mira/semi-regular variables, IRC objects, OH/IR sources and proto-planetary nebulae. We found the highest H_2_O detection rate for the type of stars with a thin dust envelope (Mira/semi-regular variables) among other types of sources. This is attributed to the smaller distances to such stars in the sample. The velocity spread of the H_2_O maser profile has an increasing tendency with the IRAS color, though it becomes more difficult to access this color dependence beyond an edge of the transition of the (oxygen-rich) Asymptotic Giant Branch stars to protoplanetary nebulae in the two-color diagram.
- ID:
- ivo://CDS.VizieR/J/A+A/434/613
- Title:
- Water maser survey of methanol maser sources
- Short Name:
- J/A+A/434/613
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- High sensitivity observations of the 22GHz water maser emission have been carried out with the Effelsberg 100m radio telescope. The observed sample was 79 candidate high-mass protostellar objects from a flux-limited sample of 6.7GHz methanol sources (Szymczak et al., 2002A&A...392..277S). Water maser emission was found in 41 sources of which 28 were not previously catalogued.
23330. Wavelength calibration
- ID:
- ivo://CDS.VizieR/J/A+AS/128/409
- Title:
- Wavelength calibration
- Short Name:
- J/A+AS/128/409
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Thorium-Argon lamps are commonly used as wavelength calibration units at moderately high spectral resolutions because of the richness of the thorium spectrum in the visual. The inclusion of blended lines whose position is assumed to coincide with the laboratory wavelength of the main component is shown to result in a calibration precision significantly worse than the intrinsic random noise limit. In order to avoid this degradation of the calibration, we present resolution-dependent Th-Ar wavelengths in the region 277 to >1000nm for use at pixel-scales (pixel-size expressed in wavelength units) between {lambda}/2.5x10+4 and {lambda}/10+5.
