- ID:
- ivo://CDS.VizieR/J/A+A/552/L2
- Title:
- SINFONI K-band observations of IRS54(YLW52)
- Short Name:
- J/A+A/552/L2
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Molecular outflows from very low-mass stars (VLMSs) and brown dwarfs have been studied very little. So far, only a few CO outflows have been observed, allowing us to map the immediate circumstellar environment. We present the first spatially resolved H_2_ emission around IRS54 (YLW52), a ~0.1-0.2M_{sun}_ Class I source. By means of VLT SINFONI K-band observations, we probed the H2 emission down to the first ~50AU from the source. The molecular emission shows a complex structure delineating a large outflow cavity and an asymmetric molecular jet. Thanks to the detection of several H_2_transitions, we are able to estimate average values along the jet-like structure (from source position to knot D) of Av~28mag, T~2000-3000K, and H_2_column density N(H_2)~1.7x10^17cm^-2. This allows us to estimate a mass loss rate of ~2x10^-10M_{sun}_/yr for the warm H_2_component . In addition, from the total flux of the Br gamma line, we infer an accretion luminosity and mass accretion rate of 0.64L_{sun}_ and ~3x10^-7M_{sun}_/yr, respectively. The outflow structure is similar to those found in low-mass Class I and CTTS. However, the Lacc/Lbol ratio is very high (~80%), and the mass accretion rate is about one order of magnitude higher when compared to objects of roughly the same mass, pointing to the young nature of the investigated source.
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Search Results
- ID:
- ivo://CDS.VizieR/J/A+A/557/A94
- Title:
- SiO and HCO+ massive molecular outflows
- Short Name:
- J/A+A/557/A94
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present the results of a study of 14 molecular outflows associated with high-mass star formation. We used the IRAM30m telescope to characterize the outflow emission in the SiO(2-1), SiO(5-4) and HCO^+^(1-0) lines. We detect outflows in all the 14 high-mass star-forming regions in both, the SiO and HCO^+^ lines. Six of the fourteen outflows show bipolarity. The physical parameters derived for these outflows are consistent with outflows powered by massive young stellar objects with luminosities in the range 10^3^-10^4^L_{sun}_. We found a decrease of the SiO abundance (from 10^-8^ to 10^-9^) as the object evolves in time, while there are hints of a possible increase of the HCO^+^ outflow energetics with time. These results suggest a scenario in which SiO is largely enhanced in the first evolutionary stages, probably due to strong shocks produced by the protostellar jet. As the object evolves, the power of the jet would decrease and so does the SiO abundance. During this process, however, the material surrounding the protostar would have been swept up by the jet, and the outflow activity, traced by entrained molecular material (HCO^+^), would increase with time.
- 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.
1014. 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.
- ID:
- ivo://CDS.VizieR/J/PASJ/58/529
- Title:
- SiO Maser Survey in Galactic Bulge
- Short Name:
- J/PASJ/58/529
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We surveyed 291 MSX/2MASS infrared objects in the 7{deg}x2{deg} area of the galactic center in the 43GHz SiO J=1-0 v=1 and 2 maser lines, obtaining accurate radial velocities of 163 detected objects. The surveyed area is the region where the IRAS catalog is incomplete due to contamination by high source density. The objects in the present MSX/2MASS sample were chosen to have similar infrared characteristics to those of the previous SiO-maser-survey samples based on the color-selected IRAS sources. The sampling based on the 2MASS catalog causes a bias to the foreside objects of the bulge due to heavy obscuration by interstellar dust; the detections considerably leaned on the V_lsr_<0 side.
- ID:
- ivo://CDS.VizieR/J/PASJ/55/229
- Title:
- SiO maser survey of cold IRAS sources
- Short Name:
- J/PASJ/55/229
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present the results of observations of cold IRAS sources in the Galactic disk area, -10{deg}<l<100{deg} and |b|<5{deg}, in the SiO J=1-0, v=1 and 2 maser lines. SiO masers were detected in 51 out of 143 observed sources; 45 were new detections in SiO masers. The selected IRAS sources were objects with dust temperatures of between 160 and 280K.
- ID:
- ivo://CDS.VizieR/J/PASJ/56/765
- Title:
- SiO maser survey of IRAS sources
- Short Name:
- J/PASJ/56/765
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We surveyed 401 color-selected IRAS sources in the galactic disk in the SiO J=1-0, v=1 and 2 maser lines at 43GHz, resulting in 254 (239 new) detections. The observed sources lie mostly in a strip of the inner galactic disk with boundaries -10{deg}<l<40{deg} and |b|<3{deg}. This survey provides radial velocities of inner-disk stars for which optical measurements cannot be made due to interstellar extinction.
- ID:
- ivo://CDS.VizieR/J/PASJ/55/203
- Title:
- SiO maser survey toward inner Galactic disk
- Short Name:
- J/PASJ/55/203
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present the results of an SiO maser survey for color-selected IRAS sources in the area 40{deg}<l<70{deg} and |b|<10{deg} in the SiO J=1-0, v=1 and 2 transitions (~43GHz). We detected 134 out of 272 observed sources in SiO masers; 127 were new detections. A systematic difference in the detection rates between SiO and OH maser searches was found.
1019. SMC AGN in XMM-Newton
- ID:
- ivo://CDS.VizieR/J/A+A/622/A29
- Title:
- SMC AGN in XMM-Newton
- Short Name:
- J/A+A/622/A29
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Finding active galactic nuclei (AGN) behind the Magellanic Clouds (MCs) is difficult because of the high stellar density in these fields. Although the first AGN behind the Small Magellanic Cloud (SMC) were reported in the 1980s, it is only recently that the number of AGN known behind the SMC has increased by several orders of magnitude. The mid-infrared colour selection technique has proven to be an efficient means of identifying AGN, especially obscured sources. The X-ray regime is complementary in this regard and we use XMM-Newton observations to support the identification of AGN behind the SMC. We present a catalogue of AGN behind the SMC by correlating an updated X-ray point-source catalogue from our XMM-Newton survey of the SMC with previously identified AGN from the literature as well as a list of candidates obtained from the ALLWISE mid-infrared colour-selection criterion. We studied the properties of the sample with respect to their redshifts, luminosities, and X-ray spectral characteristics. We also identified the near-infrared counterpart of the sources from the VISTA observations. The redshift and luminosity distributions of the sample (where known) indicate that we detect sources ranging from nearby Seyfert galaxies to distant and obscured quasars. The X-ray hardness ratios are compatible with those typically expected for AGN, and the VISTA colours and variability are also consistent with AGN. A positive correlation was observed between the integrated X-ray flux (0.2-12keV) and the ALLWISE and VISTA magnitudes. We further present a sample of new candidate AGN and candidates for obscured AGN. Together these make an interesting subset for further follow-up studies. An initial spectroscopic follow-up of 6 out of the 81 new candidates showed that all six sources are active galaxies, although two have narrow emission lines.
- ID:
- ivo://CDS.VizieR/J/ApJ/744/20
- Title:
- S^4^MC project: 6 star forming regions PAHs
- Short Name:
- J/ApJ/744/20
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present results of mid-infrared spectroscopic mapping observations of six star-forming regions in the Small Magellanic Cloud (SMC) from the Spitzer Spectroscopic Survey of the SMC (S^4^MC). We detect the mid-IR emission from polycyclic aromatic hydrocarbons (PAHs) in all of the mapped regions, greatly increasing the range of environments where PAHs have been spectroscopically detected in the SMC. We investigate the variations of the mid-IR bands in each region and compare our results to studies of the PAH bands in the SINGS sample and in a sample of low-metallicity starburst galaxies. PAH emission in the SMC is characterized by low ratios of the 6-9um features relative to the 11.3um feature and weak 8.6 and 17.0um features. Interpreting these band ratios in the light of laboratory and theoretical studies, we find that PAHs in the SMC tend to be smaller and less ionized than those in higher metallicity galaxies.
