- ID:
- ivo://CDS.VizieR/J/A+A/651/A25
- Title:
- 4 short-period comets spectra
- Short Name:
- J/A+A/651/A25
- Date:
- 22 Feb 2022
- Publisher:
- CDS
- Description:
- We present the results of millimetre-wave spectroscopic observations and spectral surveys of the following short-period comets: 21P/Giacobini-Zinner in September 2018, 41P/Tuttle-Giacobini-Kresak in April 2017, 64P/Swift-Gehrels and 38P/Stephan-Oterma in December 2018, carried out with the IRAM 30-m radio telescope at wavelengths between 1 and 3~mm. Comet 21P was also observed in November 1998 with the IRAM 30-m, JCMT and CSO radio telescopes at wavelengths from 0.8 to 3~mm. The abundances of the following molecules have been determined in those comets: HCN, CH_3_OH, CS, H_2_CO, CH_3_CN and H_2_S in comet 21P, HCN and CH_3_OH in 41P, HCN, CH_3_OH and CS in 64P, and CH_3_OH in 38P. The three last comets, classified as carbon-chain typical from visible spectro-photometry, are relatively rich in methanol (3.5 to 5% relative to water). On the other hand, comet 21P, classified as carbon-chain depleted, shows abundances relative to water which are low for methanol (1.7%), very low for H2S (0.1%) and also relatively low for H2CO (0.16%) and CO (<2.5%). Observations of comet 21P do not show any change in activity and composition between the 1998 and 2018 perihelions. Sensitive upper limits on the abundances of other molecules such as CO, HNCO, HNC or SO are also reported for these comets.
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Search Results
- ID:
- ivo://CDS.VizieR/J/ApJS/240/14
- Title:
- SIGGMA: inner galaxy data release
- Short Name:
- J/ApJS/240/14
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The Survey of Ionized Gas of the Galaxy, Made with the Arecibo telescope (SIGGMA) provides a fully sampled view of the radio recombination line (RRL) emission from the portion of the Galactic plane visible with Arecibo. Observations use the Arecibo L-band Feed Array, which has a FWHM beam size of 3.4'. Twelve hydrogen RRLs from H163{alpha} to H174{alpha} are located within the instantaneous bandpass from 1225MHz to 1525MHz. We provide here cubes of average ("stacked") RRL emission for the inner Galaxy region 32{deg}<=l<=70{deg}, |b|<=1.5{deg}, with an angular resolution of 6'. The stacked RRL rms at 5.1km/s velocity resolution is ~0.65mJy/beam, making this the most sensitive large-scale fully sampled RRL survey extant. We use SIGGMA data to catalog 319 RRL detections in the direction of 244 known HII regions, and 108 new detections in the direction of 79 HII region candidates. We identify 11 carbon RRL emission regions, all of which are spatially coincident with known HII regions. We detect RRL emission in the direction of 14 of the 32 supernova remnants (SNRs) found in the survey area. This RRL emission frequently has the same morphology as the SNRs. The RRL velocities give kinematic distances in agreement with those found in the literature, indicating that RRLs may provide an additional tool to constrain distances to SNRs. Finally, we analyze the two bright star-forming complexes: W49 and W51. We discuss the possible origins of the RRL emission in directions of SNRs W49B and W51C.
- ID:
- ivo://CDS.VizieR/J/A+A/545/A65
- Title:
- S5 0836+710 image at 1.6GHz
- Short Name:
- J/A+A/545/A65
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The remarkable stability of extragalactic jets is surprising, given the reasonable possibility of the growth of instabilities. In addition, much work in the literature has invoked this possibility to explain observed jet structures and obtain information about the jet from these structures. For example, it has been shown that the observed helical structures in the jet in S5 0836+710 could be associated with helical pressure waves generated by a Kelvin-Helmholtz instability. Our aim is to resolve the arc-second structure of the jet in the quasar S5 0836+710 and confirm the lack of a hot-spot (reverse jet-shock) found by present observing arrays, as this lack implies a loss of jet collimation before interaction with the intergalactic medium.
- 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.
- 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.