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1151. Observations of SiO masers
ID:
ivo://CDS.VizieR/J/ApJ/669/446
Title:
Observations of SiO masers
Short Name:
J/ApJ/669/446
Date:
21 Oct 2021
Publisher:
CDS
Description:
We present the results of SiO millimeter line observations of a sample of known SiO maser sources covering a wide dust temperature range. A cold part of the sample was selected from the SiO maser sources found in our recent SiO maser survey of cold dusty objects. The aim of the present research is to investigate the causes of the correlation between infrared colors and SiO maser intensity ratios among different transition lines. In particular, the correlation between infrared colors and SiO maser intensity ratio among the J=1-0 v=1, 2, and 3 lines are our main concern in this paper. We observed in total 75 SiO maser sources with the Nobeyama 45m telescope quasi-simultaneously in the SiO J=1-0 v=0, 1, 2, 3, 4 and J=2-1 v=1, 2 lines. We also observed the sample in the ^29^SiO J=1-0 v=0 and J=2-1 v=0 lines, ^30^SiO J=1-0 v=0 line, and the H_2_O 61,6-52,3 line.
1152. Observed chemical structure of L1544
ID:
ivo://CDS.VizieR/J/A+A/606/A82
Title:
Observed chemical structure of L1544
Short Name:
J/A+A/606/A82
Date:
21 Oct 2021
Publisher:
CDS
Description:
We present the emission maps of 39 different molecular transitions belonging to 22 different molecules in the central 6.25 arcmin^2^ of L1544. We classified our sample in five families, depending on the location of their emission peaks within the core. Furthermore, to systematically study the correlations among different molecules, we have performed the principal component analysis (PCA) on the integrated emission maps. The PCA allows us to reduce the amount of variables in our dataset. Finally, we compare the maps of the first three principal components with the H_2_ column density map, and the T_dust_ map of the core. The results of our qualitative analysis is the classification of the molecules in our dataset in the following groups: (i) the c-C_3_H_2_ family (carbon chain molecules like C_3_H and CCS), (ii) the dust peak family (nitrogen-bearing species like N_2_H^+^ ), (iii) the methanol peak family (oxygen-bearing molecules like methanol, SO and SO_2_, (iv) the HNCO peak family (HNCO, propyne and its deuterated isotopologues). Only HC^18^O^+^ and ^13^CS do not belong to any of the above mentioned groups. The principal component maps allow us to confirm the (anti-)correlations among different families that were described in a first qualitative analysis, but also points out the correlation that could not be inferred before. For example, the molecules belonging to the dust peak and the HNCO peak families correlate in the third principal component map, hinting on a chemical/physical correlation.
1153. Observed quantities from B3 sources
ID:
ivo://CDS.VizieR/J/AJ/98/419
Title:
Observed quantities from B3 sources
Short Name:
J/AJ/98/419
Date:
21 Oct 2021
Publisher:
CDS
Description:
This catalog contains results of a large program of optical identifications of radio sources from the Third Bologna (B3) Catalog (Ficarra et al., 1985A&AS...59..255F, Cat.<VIII/37>). A homogeneous sample of 1103 radio sources, selected from the B3 catalog at 408 MHz and covering a flux density range from 2.0 to 0.1 Jy, has been mapped at 1465 MHz using the VLA at 15" resolution. Both positional and structural information have been derived and are presented here. Optical identifications have been attempted for all of the sources within the range of right ascension studied, using the Palomar Sky Survey prints, resulting in 354 proposed identifications. The RA range was restricted to exclude sky areas at low galactic latitude, because obscuration makes these unsuitable for optical identifications, and confusion makes them unsuitable for VLA snapshot-mode observations. Thus the samples were selected only from the RA intervals 23h-3h, 7h-15h. The number of rows of this table (1474) is larger than the number of sources (1103) because each radio component of multiple sources is listed as a separate line.
1154. Observed transitions of CH_3_OH and CH_3_CHO
ID:
ivo://CDS.VizieR/J/ApJ/880/138
Title:
Observed transitions of CH_3_OH and CH_3_CHO
Short Name:
J/ApJ/880/138
Date:
21 Oct 2021
Publisher:
CDS
Description:
IRAM 30m Observations toward eight protostellar outflow sources were taken in the 96-176GHz range. Transitions of CH_3_OH and CH_3_CHO were detected in seven of them. The integrated emissions of the transitions of each species that fell into the observed frequency range were measured and fit using RADEX and LTE models. Column densities and gas properties inferred from this fitting are presented. The ratio of the A and E-type isomers of CH_3_OH indicates that the methanol observed in these outflows was formed on the grain surface. Both species demonstrate a reduction of terminal velocity in their line profiles in faster outflows, indicating destruction in the post-shock gas phase. This destruction, and a near constant ratio of the CH_3_OH and CH_3_CHO column densities, imply it is most likely that CH_3_CHO also forms on the grain surface.
1155. ODISEA: Disk dust mass distributions
ID:
ivo://CDS.VizieR/J/ApJ/875/L9
Title:
ODISEA: Disk dust mass distributions
Short Name:
J/ApJ/875/L9
Date:
21 Oct 2021
Publisher:
CDS
Description:
As protostars evolve from optically faint/infrared-bright (Class I) sources to optically bright/infrared-faint (Class II) the solid material in their surrounding disks accumulates into planetesimals and protoplanets. The nearby, young Ophiuchus star-forming region contains hundreds of protostars in a range of evolutionary states. Using the Atacama Large Millimeter Array to observe their millimeter continuum emission, we have measured masses of, or placed strong upper limits on, the dust content of 279 disks. The masses follow a log-normal distribution with a clear trend of decreasing mass from less to more evolved protostellar infrared class. The (logarithmic) mean Class I disk mass, M=3.8M_{Earth}_, is about 5 times greater than the mean Class II disk mass, but the dispersion in each class is so high, {sigma}_logM_~0.8-1, that there is a large overlap between the two distributions. The disk mass distribution of flat-spectrum protostars lies in between Classes I and II. In addition, three Class III sources with little to no infrared excess are detected with low disk masses, M~0.3M_{Earth}_. Despite the clear trend of decreasing disk mass with protostellar evolutionary state in this region, a comparison with surveys of Class II disks in other regions shows that masses do not decrease monotonically with age. This suggests that the cloud-scale environment may determine the initial disk mass scale or that there is substantial dust regeneration after 1Myr.
1156. OH 5-cm line survey in late-type stars
ID:
ivo://CDS.VizieR/J/A+A/394/975
Title:
OH 5-cm line survey in late-type stars
Short Name:
J/A+A/394/975
Date:
21 Oct 2021
Publisher:
CDS
Description:
We have undertaken a comprehensive search for 5-cm excited OH maser emission from evolved stars representative of various stages of late stellar evolution. Observed sources were selected from known 18-cm OH sources. This survey was conducted with the 100-m Effelsberg telescope, at 6.0GHz in Sep 2000, to achieve high signal to noise ratio observations and a sensitivity limit of about 0.05 to 0.1Jy. A total of 65 stellar sources were searched for both main line and satellite line emission. We confirm the previous detection of 5 cm OH in Vy 2-2, do not confirm emission from NML-Cyg and do not report any other new detection within the above sensitivity limit. The number of observed sources is 67.
1157. OH detections from circumstellar shells
ID:
ivo://CDS.VizieR/J/A+AS/111/237
Title:
OH detections from circumstellar shells
Short Name:
J/A+AS/111/237
Date:
21 Oct 2021
Publisher:
CDS
Description:
We identified 240 accessible circumstellar shells with water and/or SiO masers, and used the Arecibo and Nancay radio telescopes to search for mainline OH emission from them. Our targets are often Mira variables without previously known mainline masers. This search results in 89 detections, of which 77 are new.
1158. OH/H2O masers database
ID:
ivo://CDS.VizieR/J/A+AS/137/43
Title:
OH/H2O masers database
Short Name:
J/A+AS/137/43
Date:
21 Oct 2021
Publisher:
CDS
Description:
Table 3 contains VLA spectra and positions for OH and H2O maser spots in 74 star-forming regions mapped by Forster and Caswell (1989A&A...213..339F). Galactic coordinates are given, followed by offset positions of the 22GHz continuum peak (HII) if detected, and the flux, velocity and positions of OH and H_2_O maser spots mapped in that field.
1159. OH maser emission from IRAS sources
ID:
ivo://CDS.VizieR/J/A+A/327/755
Title:
OH maser emission from IRAS sources
Short Name:
J/A+A/327/755
Date:
21 Oct 2021
Publisher:
CDS
Description:
A high-sensitivity search for water maser emission at 22.2 GHz has been performed on a sample of 91 IRAS point sources at high-latitudes. The aim of the survey is to verify if these clouds are capable of star formation as indicated by the presence of water masers. The sample is based on the recent work of Magnani et al. (1995ApJS...96..159M) who have identified 192 infrared objects from the IRAS Faint Source Survey possibly associated with translucent clouds at galactic latitudes |b|>=30{deg}. These IRAS sources have far-infrared colours typical of young stellar objects and pre-main-sequence stars and thus provide a starting list for further studies about their actual nature. H_2_O maser emission is a good diagnostic of the presence of dense gas and of recent star formation. We did not find water maser emission at a level of 0.2-0.5Jy (3{sigma}) in any of the 91 objects. The negative result indicates that these high-latitude sources do not represent potential sites of star formation, consistent with the fact that most high-latitude molecular clouds do not appear gravitationally bound.
1160. OH maser emission from star forming regions
ID:
ivo://CDS.VizieR/J/A+A/414/235
Title:
OH maser emission from star forming regions
Short Name:
J/A+A/414/235
Date:
21 Oct 2021
Publisher:
CDS
Description:
High sensitivity observations of all four transitions of the ground state at 18cm of OH in both senses of circular polarization have been carried out with the Nancay radio telescope. The sample was a set of 100 star forming regions detected in a recent unbiased survey of 6668MHz methanol masers (Szymczak et al., 2002A&A...392..277S). OH maser emission was found in 55 objects of which 31 were not previously catalogued.