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921. PN medium-resolution spectra
ID:
ivo://CDS.VizieR/J/ApJS/124/195
Title:
PN medium-resolution spectra
Short Name:
J/ApJS/124/195
Date:
21 Oct 2021
Publisher:
CDS
Description:
We present medium-resolution (R~700) near-infrared (lambda=1-2.5m) spectra of a sample of planetary nebulae (PNe). A narrow slit was used which sampled discrete locations within the nebulae; observations were obtained at one or more positions in the 41 objects included in the survey. The PN spectra fall into one of four general categories: HI emission line-dominated PNe, HI and H_2_ emission line PNe, H_2_ emission line-dominated PNe, and continuum-dominated PNe. These categories correlate with morphological type, with the elliptical PNe falling into the first group, and the bipolar PNe primarily in the H_2_ and continuum emission groups. The categories also correlate with C/O ratio, with the O-rich objects generally falling into the first group and the C-rich objects in the other groups. Other spectral features were observed in all categories, such as continuum emission from the central star, C_2_, CN, and CO emission, and warm dust continuum emission toward the long wavelength end of the spectra. Molecular hydrogen was detected for the first time in four PNe. An excitation analysis was performed using the H_2_ line ratios for all of the PN spectra in the survey where a sufficient number of lines were observed.
922. POKER (P. Of k EstimatoR) code
ID:
ivo://CDS.VizieR/J/A+A/535/A90
Title:
POKER (P. Of k EstimatoR) code
Short Name:
J/A+A/535/A90
Date:
21 Oct 2021
Publisher:
CDS
Description:
We describe the implementation of an angular power spectrum estimator in the at sky approximation. POKER (P. Of k EstimatoR) is based on the MASTER algorithm developped by Hivon and collaborators in the context of CMB anisotropy. It works entirely in discrete space and can be applied to arbitrary high angular resolution maps. It is therefore particularly suitable for current and future infrared to sub-mm observations of diffuse emission, whether Galactic or cosmological.
923. Polarization hole in a starless core
ID:
ivo://CDS.VizieR/J/A+A/569/L1
Title:
Polarization hole in a starless core
Short Name:
J/A+A/569/L1
Date:
21 Oct 2021
Publisher:
CDS
Description:
We aim to investigate the polarization properties of a starless core in a very early evolutionary stage. Linear polarization data reveal the properties of the dust grains in the distinct phases of the interstellar medium. Our goal is to investigate how the polarization degree and angle correlate with the cloud and core gas. We use optical, near infrared and submillimeter polarization observations toward the starless object Pipe-109 in the Pipe nebula. Our data cover a physical scale range of 0.08 to 0.4pc, comprising the dense gas, envelope and the surrounding cloud. The cloud polarization is well traced by the optical data. The near infrared polarization is produced by a mixed population of grains from the core border and the cloud gas. The optical and near infrared polarization toward the cloud reach the maximum possible value and saturate with respect to the visual extinction. The core polarization is predominantly traced by the submillimeter data and have a steep decrease with respect to the visual extinction. Modeling of the submillimeter polarization indicates a magnetic field main direction projected onto the plane-of-sky and loss of grain alignment for densities higher than 6x10^4^cm^-3^ (or A_V_>30mag). Pipe-109 is immersed in a magnetized medium, with a very ordered magnetic field. The absence of internal source of radiation significantly affects the polarization efficiencies in the core, creating a polarization hole at the center of the starless core. This result supports the theory of dust grain alignment via radiative torques.
924. Polarization of stars in Taurus
ID:
ivo://CDS.VizieR/J/ApJ/741/21
Title:
Polarization of stars in Taurus
Short Name:
J/ApJ/741/21
Date:
21 Oct 2021
Publisher:
CDS
Description:
We present maps of the plane-of-sky magnetic field within two regions of the Taurus molecular cloud: one in the dense core L1495/B213 filament and the other in a diffuse region to the west. The field is measured from the polarization of background starlight seen through the cloud. In total, we measured 287 high-quality near-infrared polarization vectors in these regions. In L1495/B213, the percent polarization increases with column density up to A_V_~9mag, the limits of our data. The radiative torques model for grain alignment can explain this behavior, but models that invoke turbulence are inconsistent with the data. We also combine our data with published optical and near-infrared polarization measurements in Taurus. Using this large sample, we estimate the strength of the plane-of-sky component of the magnetic field in nine subregions. This estimation is done with two different techniques that use the observed dispersion in polarization angles. Our values range from 5 to 82uG and tend to be higher in denser regions. In all subregions, the critical index of the mass-to-magnetic flux ratio is sub-unity, implying that Taurus is magnetically supported on large scales (~2pc). Within the region observed, the B213 filament takes a sharp turn to the north and the direction of the magnetic field also takes a sharp turn, switching from being perpendicular to the filament to becoming parallel. This behavior can be understood if we are observing the rim of a bubble. We argue that it has resulted from a supernova remnant associated with a recently discovered nearby gamma-ray pulsar.
925. Positions and photometry of HII knots in M51
ID:
ivo://CDS.VizieR/J/ApJ/633/871
Title:
Positions and photometry of HII knots in M51
Short Name:
J/ApJ/633/871
Date:
21 Oct 2021
Publisher:
CDS
Description:
Far-ultraviolet to far-infrared images of the nearby galaxy NGC 5194 (M51a), from a combination of space-based (Spitzer, GALEX, and Hubble Space Telescope) and ground-based data, are used to investigate local and global star formation and the impact of dust extinction. The Spitzer data provide unprecedented spatial detail in the infrared, down to sizes 500 pc at the distance of NGC 5194. The multiwavelength set is used to trace the relatively young stellar populations, the ionized gas, and the dust absorption and emission in HII-emitting knots, over 3 orders of magnitude in wavelength range.
926. Positions of Triton with Sheshan Station telescope
ID:
ivo://CDS.VizieR/J/AJ/161/237
Title:
Positions of Triton with Sheshan Station telescope
Short Name:
J/AJ/161/237
Date:
20 Jan 2022
Publisher:
CDS
Description:
The large time span and precise observational data of natural satellites is of great significance for updating their ephemerides and studying their dynamic characteristics. With the help of the new image-processing methods and the Gaia DR2 catalog, all CCD images of Triton taken with the 1.56m telescope of Shanghai Astronomical Observatory during 2005-2009 were reanalyzed. The median filtering algorithm is used for image preprocessing to remove the influence of the halo of Neptune, and an upgraded modified moment, called the intensity-square-weighted centroiding method, is applied to determine the centroids of the stars and Triton. A total of 2299 positions of Triton were obtained, including 263 new observed positions and 2036 updated observed positions. Such five-year time span data with high precision will be very helpful to improve the orbit parameters of Triton.
927. Possible new planetary nebulae in IRAS PSC
ID:
ivo://CDS.VizieR/J/A+AS/76/317
Title:
Possible new planetary nebulae in IRAS PSC
Short Name:
J/A+AS/76/317
Date:
21 Oct 2021
Publisher:
CDS
Description:
A method for searching new possible planetary nebulae among the unidentified sources of the IRAS Point Source Catalog is described. Sources were selected according to their far infrared colours, proximity to galactic equator, and quality of the IRAS detection. A catalog of 388 new possible planetary nebulae is presented and the properties of the selected sample are discussed.
928. Predicted dust emissivity in 100-10000um bands
ID:
ivo://CDS.VizieR/J/A+A/534/A118
Title:
Predicted dust emissivity in 100-10000um bands
Short Name:
J/A+A/534/A118
Date:
21 Oct 2021
Publisher:
CDS
Description:
In a previous paper we proposed a new model for the emission by amorphous astronomical dust grains, based on solid-state physics. The model uses a description of the disordered charge distribution (DCD) combined with the presence of two-level systems (TLS) defects in the amorphous solid composing the grains. The goal of this paper is to compare this new model to astronomical observations of different Galactic environments in the far-infrared/ submillimeter, in order to derive a set of canonical model parameters to be used as a Galactic reference to be compared to in future Galactic and extragalactic studies. We compare the TLSmodel with existing astronomical data. We consider the average emission spectrum at high latitudes in our Galaxy as measured with FIRAS and WMAP, as well as the emission from Galactic compact sources observed with the Archeops balloon experiment, for which an inverse relationship between the dust temperature and the emissivity spectral index has been proven.
929. Predicted positions of {beta}Pictoris b and c
ID:
ivo://CDS.VizieR/J/AJ/161/179
Title:
Predicted positions of {beta}Pictoris b and c
Short Name:
J/AJ/161/179
Date:
18 Jan 2022
Publisher:
CDS
Description:
We present a comprehensive orbital analysis to the exoplanets {beta}Pictoris b and c that resolves previously reported tensions between the dynamical and evolutionary mass constraints on {beta}Picb. We use the Markov Chain Monte Carlo orbit code orvara to fit 15years of radial velocities and relative astrometry (including recent GRAVITY measurements), absolute astrometry from Hipparcos and Gaia, and a single relative radial velocity measurement between {beta}Pic A and b. We measure model-independent masses of 9.3_-2.5_^+2.6^M_Jup_ for {beta}Picb and 8.3{+/-}1.0M_Jup_ for {beta}Picc. These masses are robust to modest changes to the input data selection. We find a well-constrained eccentricity of 0.119{+/-}0.008 for {beta}Picb, and an eccentricity of 0.21_-0.09_^+0.16^ for {beta}Picc, with the two orbital planes aligned to within ~0.5{deg}. Both planets' masses are within ~1{sigma} of the predictions of hot-start evolutionary models and exclude cold starts. We validate our approach on N-body synthetic data integrated using REBOUND. We show that orvara can account for three-body effects in the {beta}Pic system down to a level ~5 times smaller than the GRAVITY uncertainties. Systematics in the masses and orbital parameters from orvara's approximate treatment of multiplanet orbits are a factor of ~5 smaller than the uncertainties we derive here. Future GRAVITY observations will improve the constraints on {beta}Picc's mass and (especially) eccentricity, but improved constraints on the mass of {beta}Picb will likely require years of additional radial velocity monitoring and improved precision from future Gaia data releases.
930. Properties of cores in OMC 2/3
ID:
ivo://CDS.VizieR/J/A+A/588/A30
Title:
Properties of cores in OMC 2/3
Short Name:
J/A+A/588/A30
Date:
21 Oct 2021
Publisher:
CDS
Description:
We present new measurements of the dust emissivity index, {beta}, for the high-mass, star-forming OMC 2/3 filament. We combined 160-500um data from Herschel with long-wavelength observations at 2mm and fit the spectral energy distributions across a=~2pc long, continuous section of OMC 2/3 at 15000AU (0.08pc) resolution. With these data, we measured {beta} and reconstructed simultaneously the filtered-out large-scale emission at 2mm. We implemented both variable and fixed values of {beta}, finding that {beta}=1.7-1.8 provides the best fit across most of OMC 2/3. These {beta} values are consistent with a similar analysis carried out with filtered Herschel data. Thus, we show that {beta} values derived from spatial filtered emission maps agree well with those values from unfiltered data at the same resolution. Our results contradict the very low {beta} values (~0.9) previously measured in OMC 2/3 between 1.2mm and 3.3mm data, which we attribute to elevated fluxes in the 3.3mm observations. Therefore, we find no evidence of rapid, extensive dust grain growth in OMC 2/3. Future studies with Herschel data and complementary ground-based long-wavelength data can apply our technique to obtain reliable determinations of {beta} in nearby cold molecular clouds.