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Start Over Subject infrared astronomy Content Level Research
1011. Simulated IR spectra of PN Hubble 12
ID:
ivo://CDS.VizieR/J/A+A/655/A46
Title:
Simulated IR spectra of PN Hubble 12
Short Name:
J/A+A/655/A46
Date:
10 Mar 2022 07:09:39
Publisher:
CDS
Description:
We present a visible-infrared imaging study of young planetary nebula (PN) Hubble 12 (Hb 12; PN G111.8-02.8) obtained with Hubble Space Telescope (HST) archival data and our own Canada-France-Hawaii Telescope (CFHT) measurements. Deep HST and CFHT observations of this nebula reveal three pairs of bipolar structures and an arc-shaped filament near the western waist of Hb 12. The existence of nested bipolar lobes together with the presence of H2 knots suggests that these structures originated from several mass-ejection events during the pre-PN phase. To understand the intrinsic structures of Hb 12, a three-dimensional model enabling the visualisation of this PN at various orientations was constructed. The modelling results show that Hb 12 may resemble other nested hourglass nebulae, such as Hen 2-320 and M 2-9, suggesting that this type of PN may be common and the morphologies of PNs are not so diverse as is shown by their visual appearances. The infrared spectra show that this PN has a mixed chemistry. We discuss the possible material that may cause the unidentified infrared emissions. The analyses of the infrared spectra and the spectral energy distribution suggest the existence of a cool companion in the nucleus of this object.
1012. SINFONI K-band observations of IRS54(YLW52)
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.
1013. SiO and HCO+ massive molecular outflows
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.
1014. SiO maser search off the Galactic plane
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.
1015. 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.
1016. SiO Maser Survey in Galactic Bulge
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.
1017. SiO maser survey of cold IRAS sources
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.
1018. SiO maser survey of IRAS sources
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.
1019. SiO maser survey toward inner Galactic disk
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.
1020. 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.