- ID:
- ivo://CDS.VizieR/J/other/PPMtO/14.185
- Title:
- Purple Mountain H_2_O maser atlas
- Short Name:
- J/other/PPMtO/14
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Observations of H_2_O maser sources on the 13.7m radio telescope of Purple Mountain observatory from Aug 1990 to Jan 1994 are briefly summarized. The results of observations are presented in Table 1 and Figure 1. The total number of objects observed is 435. 195 objects are detected among them 108 are new detections. A brief description of the instrumentation and data processing are also given.
Number of results to display per page
Search Results
- ID:
- ivo://CDS.VizieR/J/ApJS/237/27
- Title:
- Radio Ammonia Mid-plane Survey (RAMPS) pilot survey
- Short Name:
- J/ApJS/237/27
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The Radio Ammonia Mid-Plane Survey (RAMPS) is a molecular line survey that aims to map a portion of the Galactic midplane in the first quadrant of the Galaxy (l=10{deg}-40{deg}, |b|<=0.4{deg}) using the Green Bank Telescope. We present results from the pilot survey, which has mapped approximately 6.5 square degrees in fields centered at l=10{deg}, 23{deg}, 24{deg}, 28{deg}, 29{deg}, 30{deg}, 31{deg}, 38{deg}, 45{deg}, and 47{deg}. RAMPS observes the NH3 inversion transitions NH_3_(1,1)-(5,5), the H_2_O 6_1,6_-5_2,3_ maser line at 22.235GHz, and several other molecular lines. We present a representative portion of the data from the pilot survey, including NH_3_(1,1) and NH_3_(2,2) integrated intensity maps, H_2_O maser positions, maps of NH_3_ velocity, NH_3_ line width, total NH_3_ column density, and NH_3_ rotational temperature.
- ID:
- ivo://CDS.VizieR/J/A+A/644/A45
- Title:
- R Crt and RT Vir Medicina spectra
- Short Name:
- J/A+A/644/A45
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Water masers emitting at a radiofrequency of 22GHz are often found in the circumstellar envelopes of evolved stars. We monitored the H_2_O maser emission of a larger sample of evolved stars of different types to study the maser properties as a function of stellar type. We wish to understand the origin and evolution of the H_2_O masers in circumstellar envelopes. In this paper, we take a closer look at R Crt and RT Vir, two nearby (<250pc) semi-regular variable stars. The findings complement our monitoring results for RX Boo and SV Peg, two other semi-regular variable stars that we have discussed in a previous paper. Within the framework of the Medicina/Effelsberg H_2_O maser monitoring programme, we observed the maser emission of R Crt and RT Vir for more than two decades with single-dish telescopes. To get insights into the distribution of maser spots in the circumstellar envelopes at different times, to get an idea of their longevity, and, where possible, to be able to link the phenomena seen in our observations to maser locations within the envelopes, we collected interferometric data for these stars, taken within the same period, from the literature. The H_2_O masers in R Crt and RT Vir exhibit brightness variations on a variety of timescales. We confirm short-time variations of individual features on timescales of months to up to 1.5 years, as seen by previous monitoring programmes. Also decade-long variations of the general brightness level, independent from individual features, were seen in both stars. These long-term variations are attributed to brightness variations occurring independently from each other in selected velocity ranges and they are independent of the optical light curve of the stars. Expected drifts in velocity of individual features are usually masked by the blending of other features with similar velocities. However, in RT Vir, we found the exceptional case of a single feature with a constant velocity over 7.5 years (<0.06km/s/yr). We attribute the long-term brightness variations to the presence of regions with higher-than-average density in the stellar wind and hosting several clouds which emit maser radiation on short timescales. These regions typically need ~20 years to cross the H_2_O maser shell, where the right conditions for exciting H_2_O masers are present. Different clouds contained in such a region all move within a narrow range of velocities, and so does their maser emission. This sometimes gives the impression of longer-living features in single-dish spectra, in spite of the short lifetimes of the individual components that lie at their origin, thus, naturally explaining the longer timescales observed. The constant velocity feature (11km/s) is likely to come from a single maser cloud, which moved through about half of RT Vir's H_2_O maser shell without changing its velocity. From this, we infer that its path was located in the outer part of the H_2_O maser shell, where RT Vir's stellar wind has, apparently, already reached its terminal outflow velocity. This conclusion is independently corroborated by the observation that the highest H_2_O maser outflow velocity in RT Vir approaches the terminal outflow velocity, as given by OH and CO observations. This is generally not observed in other semi-regular variable stars. All four stars in our study are of optical variability type SRb, indicating the absence of periodic large-amplitude variations. Therefore, any likely responses of the maser brightness to variations of the optical emission are masked by the strong short-term maser fluctuations.
- ID:
- ivo://CDS.VizieR/J/MNRAS/418/1689
- Title:
- Red MSX water maser and ammonia emissions
- Short Name:
- J/MNRAS/418/1689
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The Red MSX Source (RMS) survey has identified a sample of ~1200 massive young stellar objects (MYSOs), compact and ultra-compact HII regions from a sample of ~2000 MSX and Two Micron All Sky Survey (2MASS) colour-selected sources. We have used the 100-m Green Bank Telescope to search for 22-24GHz water maser and ammonia (1,1), (2,2) and (3,3) emission towards ~600 RMS sources located within the northern Galactic plane. We have identified 308 H_2_O masers which corresponds to an overall detection rate of ~50 per cent. We find no significant difference in the detection rate for HII regions and MYSOs which would suggest that the conditions required to produce maser emission are equally likely in both phases. Comparing the detection rates as a function of luminosity, we find the H_2_O detection rate has a positive dependence on the source luminosity, with the detection rate increasing with increasing luminosity.
- ID:
- ivo://CDS.VizieR/J/A+A/428/1019
- Title:
- Rest frequencies of methanol maser lines
- Short Name:
- J/A+A/428/1019
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We report accurate laboratory measurements of selected methanol transition frequencies between 0.834 and 230GHz in order to facilitate astronomical velocity analyses. New data have been obtained between 10 and 27GHz and between 60 and 119GHz. Emphasis has been put on known or potential interstellar maser lines as well as on transitions suitable for the investigation of cold dark clouds. Because of the narrow line widths (<0.5km/s) of maser lines and lines detected in dark molecular clouds, accurate frequencies are needed for comparison of the velocities of different methanol lines with each other as well as with lines from other species. In particular, frequencies for a comprehensive set of transitions are given which, because of their low energy levels (<20cm^-1^ or 30K), are potentially detectable in cold clouds. Global Hamiltonian fits generally do not yet yield the required accuracy. Additionally, we report transition frequencies for other lines that may be used to test and to improve existing Hamiltonian models.
- ID:
- ivo://CDS.VizieR/J/MNRAS/368/1223
- Title:
- SCUBA observations of cold cores
- Short Name:
- J/MNRAS/368/1223
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We report the results of a submillimetre continuum emission survey targeted towards 78 star formation regions, 72 of which are devoid of methanol maser and UC HII regions, identified in the Swedish ESO Submillimetre Telescope (SEST)/SEST IMaging Bolometer Array (SIMBA) millimetre continuum survey of Hill et al. (2005, Cat. <J/MNRAS/363/405>). At least 45 per cent of the latter sources, dubbed 'mm-only', detected in this survey are also devoid of the mid-infrared MSX emission. The 450- and 850-um continuum emission was mapped using the Submillimetre Common User Bolometer Array (SCUBA) instrument on the James Clerk Maxwell Telescope (JCMT). Emission is detected towards 97 per cent of the 78 sources targeted as well as towards 28 other SIMBA sources lying in the SCUBA fields. In total, we have identified 212 cores in this submillimetre survey, including 106 previously known from the SIMBA survey. Of the remaining 106 sources, 53 result from resolving a SIMBA source into multiple submillimetre components, whilst the other 53 sources are submillimetre cores, not seen in the SIMBA. Additionally, we have identified two further mm-only sources in the SIMBA images. Of the total 405 sources identified in the SIMBA survey, 255 are only seen at millimetre wavelengths.
- ID:
- ivo://CDS.VizieR/J/ApJ/869/66
- Title:
- Search for extraterrestrial intelligence with ATA
- Short Name:
- J/ApJ/869/66
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We report a novel radio autocorrelation search for extraterrestrial intelligence. For selected frequencies across the terrestrial microwave window (1-10GHz), observations were conducted at the Allen Telescope Array to identify artificial non-sinusoidal periodic signals with radio bandwidths greater than 4Hz, which are capable of carrying substantial messages with symbol rates from 4 to 10^6^Hz. Out of 243 observations, about half (101) were directed toward sources with known continuum flux >~1Jy over the sampled bandwidth (quasars, pulsars, supernova remnants, and masers), based on the hypothesis that they might harbor heretofore undiscovered natural or artificial repetitive, phase or frequency modulation. The rest of the observations were directed mostly toward exoplanet stars with no previously discovered continuum flux. No signals attributable to extraterrestrial technology were found in this study. We conclude that the maximum probability that future observations like the ones described here will reveal repetitively modulated emissions is less than 5% for continuum sources and exoplanets alike. The paper concludes by describing a new approach to expanding this survey to many more targets and much greater sensitivity using archived data from interferometers all over the world.
- ID:
- ivo://CDS.VizieR/J/A+AS/119/459
- Title:
- Search for OH maser emission
- Short Name:
- J/A+AS/119/459
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present a survey for OH maser emission at 18cm in the direction of 196 IRAS point sources. The primary aim of the survey was to detect OH maser emission from post-asymptotic giant branch (post-AGB) stars. OH emission and/or absorption was detected in the direction of 77 sources of which 57 OH detections were previously unknown, giving an overall detection rate of 39 per cent. Fourteen maser sources associated with evolved stars or planetary nebulae were found, corresponding to 7 per cent of the total observed. These included three planetary nebulae (two new OH detections), nine post-AGB stars (three new OH detections) and two cold OH/IR stars (both previously known). Two sources were of uncertain identification (both new OH detections). The remainder of the OH sources were identified with young stellar objects and with HII regions. The survey included the detection of OH maser emission from HD 101584, an early-type supergiant at high Galactic latitude. For several of the post-AGB stars, changes have occurred in the OH spectral profiles over a period of several years. This is interpreted as evidence for rapid changes in the stellar winds, due either to interactions with stellar companions, novae-like events or rapid stellar evolution.
- ID:
- ivo://CDS.VizieR/J/MNRAS/392/768
- Title:
- SED of 180 SIMBA 1.2mm sources
- Short Name:
- J/MNRAS/392/768
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Concatenating data from the millimetre regime to the infrared, we have performed spectral energy distribution (SED) modelling for 227 of the 405 millimetre continuum sources of Hill et al. (2005, Cat. J/MNRAS/363/405) which are thought to contain young massive stars in the earliest stages of their formation. Three main parameters are extracted from the fits: temperature, mass and luminosity. The method employed was the Bayesian inference, which allows a statistically probable range of suitable values for each parameter to be drawn for each individual protostellar candidate. This is the first application of this method to massive star formation.
- ID:
- ivo://CDS.VizieR/J/A+A/296/727
- Title:
- Semiregular variables H2O maser
- Short Name:
- J/A+A/296/727
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- 107 semiregular variables of spectral type M have been observed in the H2O 6(16)-5(23) line at 22.235GHz with the 100m Effelsberg radio telescope and maser emission has been detected in 23 objects, of which 10 are new detections.
