- ID:
- ivo://CDS.VizieR/J/MNRAS/363/405
- Title:
- SIMBA observations of cold cores
- Short Name:
- J/MNRAS/363/405
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We report the results of a 1.2-mm continuum emission survey toward 131 star-forming complexes suspected of undergoing massive star formation. These regions have previously been identified as harbouring a methanol maser and/or a radio continuum source [ultracompact (UC) HII region], the presence of which is in most instances indicative of massive star formation. The 1.2-mm emission was mapped using the SIMBA instrument on the 15-m Swedish ESO Submillimetre Telescope (SEST). Emission is detected toward all of the methanol maser and UC HII regions targeted, as well as towards 20 others lying within the fields mapped, implying that these objects are associated with cold, deeply embedded objects. Interestingly, there are also 20 methanol maser sites and nine UC HII regions within the fields mapped which are devoid of millimetre continuum emission. In addition to the maser and UC HII regions detected, we have also identified 253 other sources within the SIMBA maps. All of these (253) are new sources, detected solely from their millimetre continuum emission. In total, 404 sources are detected, representing four classes of sources which are distinguished by the presence of the different combination of associated tracers.
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Search Results
- ID:
- ivo://CDS.VizieR/J/AJ/145/22
- Title:
- Simultaneous SiO and H2O maser observations
- Short Name:
- J/AJ/145/22
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present the results of simultaneous observations of SiO v=1,2, ^29^SiO v=0, J=1-0, and H_2_O 6_16_-5_23_ maser lines toward 152 known stellar H_2_O maser sources using the Yonsei 21m radio telescope of the Korean VLBI Network from 2009 June to 2011 January. Both SiO and H_2_O masers were detected from 62 sources with a detection rate of 40.8%. The SiO-only maser emission without H_2_O maser detection was detected from 27 sources, while the H_2_O-only maser without SiO maser detection was detected from 22 sources. Therefore, the overall SiO maser emission was detected from 89 sources, resulting in a detection rate of 58.6%. We have identified 70 new detections of the SiO maser emission. For both H_2_O and SiO maser detected sources, the peak and integrated antenna temperatures of SiO masers are stronger than those of H_2_O masers in both Mira variables and OH/IR stars and the relative intensity ratios of H_2_O to SiO masers in OH/IR stars are larger than those in Mira variables. In addition, distributions of 152 observed sources were investigated in the IRAS two-color diagram.
- ID:
- ivo://CDS.VizieR/J/AJ/147/22
- Title:
- Simultaneous SiO and H2O maser observations. IV.
- Short Name:
- J/AJ/147/22
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Based on the simultaneous observational results of SiO and H_2_O masers toward 401 evolved stars, we have performed statistical analyses. We find that the peak and integrated intensities of SiO masers are stronger than those of H_2_O masers in both Mira variables and OH/IR stars at most optical phases. However, the relative intensity ratios of H_2_O to SiO masers in OH/IR stars are larger than those in Mira variables. Moreover, the intensity ratios of H_2_O to SiO masers are found to be increased around the optical phases from 0-0.4. The H_2_O photon luminosities also tend to be more dependent on the optical phase compared with those of SiO masers. These facts suggest that H_2_O masers are more sensitive to expanding the motion of circumstellar envelopes and also shock waves arising from the pulsations of the central star compared with SiO masers. This result may also be related to the differences in the maser location and pumping mechanism between H_2_O and SiO masers. The full width at zero power of SiO masers in Mira variables shows similar values to those of OH/IR stars, while those of H_2_ O masers in OH/IR stars show larger values than those of Mira variables. These differences may originate from the different mass-loss rates and the different location of the two masers. The mean velocity shift of SiO and H_2_O masers with respect to the stellar velocity was investigated as a function of optical phase. The velocity shift of the H_2_O masers shows that the redshifted emission dominates during the phases from 0.3-0.6, while the blueshifted emission appears at phase 0.6 and coexists with the redshifted emission during other phases. These features show an associated pattern with the CO {Delta}V=3 radial velocity curve, which exhibits a typical pulsation motion. On the other hand, the velocity shift of the SiO v=2 maser shows slightly similar features to the H_2_O maser, while that of SiO v=1 does not show these similar features. Finally, the distributions of all 401 observed sources are investigated in the IRAS two-color diagram in relation to the late evolutionary processes of asymptotic giant branch stars.
- ID:
- ivo://CDS.VizieR/J/PASJ/62/391
- Title:
- SiO and H2O masers in Stephenson 2 cluster
- Short Name:
- J/PASJ/62/391
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present the results of radio observations of red supergiants in a star cluster, Stephenson (1990AJ.....99.1867S)'s #2 (Cl Stephenson 2), and of candidates for red supergiants in three star clusters, Mercer et al. (2005ApJ...635..560M)'s #4, #8, and #13 ([MCM2005b] 4, [MCM2005b] 8 and [MCM2005b] 13), in the SiO and H_2_O maser lines. The Stephenson's #2 cluster and nearby aggregation at the southwest contain more than 15 red supergiants.
- ID:
- ivo://CDS.VizieR/J/ApJS/211/15
- Title:
- SiO and H2O maser survey toward AGB & post-AGB stars
- Short Name:
- J/ApJS/211/15
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Simultaneous observations of SiO(v=1,2,J=1-0) ^29^SiO(v=0,J=1-0) (43.122080GHz, 42.820587GHz and 42.879916GHz) and H_2_O(6_16_-5_23_) (22.235080GHz) maser lines were performed with three KVN (Korean VLBI Network) 21m single-dish radio telescopes (at Yonsei University campus, Ulsan University campus, and Tamna University campus) toward the 164 post-AGB and 143 AGB stars. Observations were carried out from 2011 February to 2012 March.
- ID:
- ivo://CDS.VizieR/J/A+A/329/219
- Title:
- 28SiO in O-rich evolved stars
- Short Name:
- J/A+A/329/219
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present simultaneous observations of several rotational lines of ^28^SiO in the v=1, 2, 3, and 4 vibrationally excited states toward O-rich evolved stars. All the data were taken in a relatively short period of 65 days, which allows a comparative study of the ^28^SiO maser lines intensities and profiles. The observed differences concerning intensity and line shape among the different maser lines suggest that infrared overlaps deeply affect the pumping of some SiO masers. We qualitatively discuss this effect with consideration to the IR overlaps at 8 {mu}m between the various SiO isotopomers and between ^28^SiO and water vapor
- ID:
- ivo://CDS.VizieR/J/A+A/642/A213
- Title:
- SiO maser emission in evolved stars
- Short Name:
- J/A+A/642/A213
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We aim to study the time evolution of the SiO maser lines in Mira-type and semi-regular variables at short timescales. We observed the SiO maser lines at 7mm and 3mm using the 40m Yebes antenna and the 30m IRAM telescope, respectively, with a minimum spacing of 1 day. We studied the semi-regular variables RX Boo and RT Vir and the Mira-type variables U Her, R LMi, R Leo, and chi Cyg.
- ID:
- ivo://CDS.VizieR/J/PASJ/59/559
- Title:
- SiO maser search off the Galactic plane
- Short Name:
- J/PASJ/59/559
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We searched for the SiO J=1-0, v=1 and 2 maser lines at ~43GHz in 277 2MASS/MSX/IRAS sources off the Galactic plane (|b|>~3{deg}), which resulted in 119 (112 new) detections. Among the new detections, two are very faint objects with MSX 12{mu}m flux densities below 2Jy. These are likely to be O-rich AGB-stars associated with dwarf-galaxy tidal tails. The sample also includes medium bright MSX objects at moderately high galactic latitudes (3{deg}<|b|<5{deg}) and in the IRAS gap at higher latitudes. A signature of a warp of the inner Galactic disk is found for a disk subsample. This warp appears relatively strongly in the area of 0{deg}<l<45{deg} and 3{deg}<|b|<5{deg}. We also found a group of stars that does not follow to the Galactic rotation. This feature appears in the Galactic disk at l~27{deg}, and extends more than 15{deg} in the galactic latitude, like a stream of tidal debris from a dwarf galaxy.
- ID:
- ivo://CDS.VizieR/J/A+AS/127/185
- Title:
- SiO masers in OH/IR stars, proto-PN and PN
- Short Name:
- J/A+AS/127/185
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present a search for SiO masers towards a sample of 126 objects including OH/IR stars, proto-planetary and planetary nebulae. All objects are classified as oxygen-rich, and most of them are associated with OH or H_2_O masers. SiO masers were found only in variable objects like the OH/IR stars and a few objects classified as proto-planetary nebulae, but with variable central stars that may be part of binary systems. In one object, OH 15.7+0.8, which appears to be varying irregularly and most likely recently left the AGB, an SiO maser was tentatively detected. Thus, we conclude that variability and SiO maser emission are closely linked, and that SiO masers disappear very soon after a star has reached the end of the AGB, when pulsation and mass loss cease.
1560. SiO maser sources
- ID:
- ivo://CDS.VizieR/J/ApJS/106/463
- Title:
- SiO maser sources
- Short Name:
- J/ApJS/106/463
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The observations in the 28SiO J=1-0 v=1, J=1-0 v=2 lines and the 29SiO J=1-0, v=0 lines were simultaneously made toward 181 color-selected IRAS sources in the outer disk of the Galaxy (at longitudes between 90 deg and 250 deg). The 28SiO lines were detected in 63 sources (56 new) and the 29SiO line in 11 sources (9 new). Most of the detections are optically variable stars, mainly Mira-type variables and a few semiregular variables. The detection rate (35%) is much lower than that of the bulge survey performed by the same observational system - the 45m telescope at Nobeyama Radio Observatory. The lower detection rate of SiO maser emission is partly attributed to the increase of contaminations by stars with C-rich circumstellar envelopes and young stellar objects in the outer disk sample. The kinematical implications of the observational results are also discussed. The luminosity distances to the SiO maser sources are estimated from their IRAS fluxes at 12um and colors. By combining the SiO radial velocity and the luminosity distance, the rotation curve of the outer Galactic disk is found to be slightly falling within the Galactocentric distance between 8.5 and 12kpc. The sources located within 20deg from the Galactic anticenter direction are used to check for a peculiar motion of the local standard of rest.
