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1211. Outer Galaxy IRAS sources and 12CO emission
ID:
ivo://CDS.VizieR/J/A+A/399/1083
Title:
Outer Galaxy IRAS sources and 12CO emission
Short Name:
J/A+A/399/1083
Date:
21 Oct 2021
Publisher:
CDS
Description:
We examined all of the IRAS sources within the Five College Radio Astronomy Observatory (FCRAO) Outer Galaxy Survey (OGS) region for associated ^12^CO emission (as accounted for in the Brunt, Kerton, and Pomerleau (2003, in press) catalogue of ^12^CO emission in the OGS). Table 1 provides a ranked listing of IRAS-CO associations and Table 2 provides a listing of those IRAS sources with no CO associations. In order to rank the various IRAS-CO associations we examined the association of random lines of sight with CO emission in the OGS. The resulting expectation numbers are provided to the reader in Table A1.
1212. Outer galaxy molecular cloud catalog
ID:
ivo://CDS.VizieR/J/ApJS/144/47
Title:
Outer galaxy molecular cloud catalog
Short Name:
J/ApJS/144/47
Date:
21 Oct 2021
Publisher:
CDS
Description:
The Five College Radio Astronomy Observatory (FCRAO) Outer Galaxy Survey (OGS) of ^12^CO(J=1-0) emission was carried out between 1994May and 1997September, using the FCRAO focal plane array QUARRY (Erickson et al. 1992, IEEE Trans. 40, 1), and initially described by Heyer et al. (1998ApJS..115..241H). The OGS covers the Galactic area 102.5<l<141.5, -3<b<54, and the velocity range -152km/s<vlsr<40km/s, at 45'' spatial resolution sampled every 50.22'', and 0.98km/s velocity resolution (1.39km/s for l<106) sampled every 0.81km/s. The typical sensitivity of the OGS at these resolutions is 0.6K (T*_R_ temperature scale). The catalog was generated in a two-phase object identification procedure. The first phase consists of grouping pixels into contiguous structures above a radiation temperature threshold of 0.8K; the second phase decomposes the first-phase objects by an enhanced version of the CLUMPFIND algorithm, using dynamic thresholding, and again with a threshold of 0.8K used for discrimination. Basic attributes of the clouds (coordinates, bounding boxes, integrated intensities, peak observed temperatures) are tabulated in the catalog. A two-dimensional elliptical Gaussian is fitted to the velocity- integrated map of each cloud; the major and minor axis sizes and major axis position angles thus derived are included in the catalog. To the spatially integrated emission line of each cloud, a Gaussian profile is fitted to measure the global linewidth. Model Gaussian clouds, truncated at 0.8K, are examined to determine the effects of biases on measured quantities, induced by truncation. Coupled with detailed analysis of the catalogued clouds, statistical corrections for the effects of truncation on measured sizes, linewidths, and integrated intensities are derived and applied, along with corrections for the effects of finite resolution on the measured attributes. The catalogued emission accounts for 76.4% of the total emission in the Outer Galaxy Survey. The deficit is shown to arise mainly from low-intensity emission on the periphery of larger objects, rather than from a large number of small and/or low-intensity features.
1213. Outer galaxy VLA survey
ID:
ivo://CDS.VizieR/J/AJ/92/787
Title:
Outer galaxy VLA survey
Short Name:
J/AJ/92/787
Date:
21 Oct 2021
Publisher:
CDS
Description:
The VLA has been used to make a "snapshot" survey of all radio continuum sources stronger than 0.3Jy at 21cm, smaller than 2arcmin, and in the area in the sky defined by l=93{deg} to 163{deg}, b=-4{deg} to +4{deg}. These objects were observed at 6 cm with a resolution of 4 arcsec and a sensitivity of 1mJy. A second set of observations were carried out to determine the spectral indices of all objects not resolved in the 6 cm survey. These objects were observed at a wavelength of 2cm with resolution and sensitivity similar to the 6cm survey. The purpose of this study was to identify objects within the disk of the outer parts of our galaxy. It is shown that the current lists of identified H II regions in this area are better than ~70% complete for H II regions in the Perseus arm or closer. The only supernova remnants remaining to be discovered in this field are either extremely young, and therefore possibly radio quiet, or they are among those objects too extended to be observed at the VLA in this survey (i.e., greater than 2arcmin in diameter).
1214. Outflows and bubbles in Taurus
ID:
ivo://CDS.VizieR/J/ApJS/219/20
Title:
Outflows and bubbles in Taurus
Short Name:
J/ApJS/219/20
Date:
21 Oct 2021
Publisher:
CDS
Description:
We have identified outflows and bubbles in the Taurus molecular cloud based on the ~100deg^2^ Five College Radio Astronomy Observatory ^12^CO(1-0) and ^13^CO(1-0) maps and the Spitzer young stellar object catalogs. In the main 44deg^2^ area of Taurus, we found 55 outflows, of which 31 were previously unknown. We also found 37 bubbles in the entire 100deg^2^ area of Taurus, none of which had been found previously. The total kinetic energy of the identified outflows is estimated to be ~3.9x10^45^erg, which is 1% of the cloud turbulent energy. The total kinetic energy of the detected bubbles is estimated to be ~9.2x10^46^erg, which is 29% of the turbulent energy of Taurus. The energy injection rate from the outflows is ~1.3x10^33^erg/s, which is 0.4-2 times the dissipation rate of the cloud turbulence. The energy injection rate from bubbles is ~6.4x10^33^erg/s, which is 2-10 times the turbulent dissipation rate of the cloud. The gravitational binding energy of the cloud is ~1.5x10^48^erg, that is, 385 and 16 times the energy of outflows and bubbles, respectively. We conclude that neither outflows nor bubbles can provide sufficient energy to balance the overall gravitational binding energy and the turbulent energy of Taurus. However, in the current epoch, stellar feedback is sufficient to maintain the observed turbulence in Taurus.
1215. 4 oxygen-rich evolved stars NH3 spectra
ID:
ivo://CDS.VizieR/J/A+A/612/A48
Title:
4 oxygen-rich evolved stars NH3 spectra
Short Name:
J/A+A/612/A48
Date:
21 Oct 2021
Publisher:
CDS
Description:
The circumstellar ammonia (NH_3_) chemistry in evolved stars is poorly understood. Previous observations and modelling showed that NH_3_ abundance in oxygen-rich stars is several orders of magnitude above that predicted by equilibrium chemistry. We would like to characterise the spatial distribution and excitation of NH_3_ in the oxygen-rich circumstellar envelopes (CSEs) of four diverse targets: IK Tau, VY CMa, OH 231.8+4.2, and IRC +10420. We observed NH_3_ emission from the ground state in the inversion transitions near 1.3cm with the Very Large Array (VLA) and submillimetre rotational transitions with the Heterodyne Instrument for the Far-Infrared (HIFI) aboard Herschel Space Observatory from all four targets. For IK Tau and VY CMa, we observed NH_3_ rovibrational absorption lines in 2 band near 10.5um with the Texas Echelon Cross Echelle Spectrograph (TEXES) at the NASA Infrared Telescope Facility (IRTF).We also attempted to search for the rotational transition within the excited vibrational state (v_2_=1) near 2mm with the IRAM 30m Telescope. Non-LTE radiative transfer modelling, including radiative pumping to the vibrational state, was carried out to derive the radial distribution of NH_3_ in the CSEs of these targets. We detected NH_3_ inversion and rotational emission in all four targets. IK Tau and VY CMa show blueshifted absorption in the rovibrational spectra. We did not detect vibrationally excited rotational transition from IK Tau. Spatially resolved VLA images of IK Tau and IRC +10420 show clumpy emission structures; unresolved images of VY CMa and OH 231.8+4.2 indicate that the spatial-kinematic distribution of NH_3_ is similar to that of assorted molecules, such as SO and SO2, that exhibit localised and clumpy emission. Our modelling shows that the NH_3_ abundance relative to molecular hydrogen is generally of the order of 10^-7^, which is a few times lower than previous estimates that were made without considering radiative pumping and is at least ten times higher than that in the carbon-rich CSE of IRC +10216. NH_3_ in OH 231.8+4.2 and IRC +10420 is found to emit in gas denser than the ambient medium. Incidentally, we also derived a new period of IK Tau from its V-band light curve. NH_3_ is again detected in very high abundance in evolved stars, especially the oxygen-rich ones. Its emission mainly arises from localised spatial-kinematic structures that are probably denser than the ambient gas. Circumstellar shocks in the accelerated wind may contribute to the production of NH_3_. Future mid-infrared spectroscopy and radio imaging studies are necessary to constrain the radii and physical conditions of the formation regions of NH_3_.
1216. Parallaxes of high mass star forming regions
ID:
ivo://CDS.VizieR/J/ApJ/783/130
Title:
Parallaxes of high mass star forming regions
Short Name:
J/ApJ/783/130
Date:
21 Oct 2021
Publisher:
CDS
Description:
Over 100 trigonometric parallaxes and proper motions for masers associated with young, high-mass stars have been measured with the Bar and Spiral Structure Legacy Survey, a Very Long Baseline Array key science project, the European VLBI Network, and the Japanese VLBI Exploration of Radio Astrometry project. These measurements provide strong evidence for the existence of spiral arms in the Milky Way, accurately locating many arm segments and yielding spiral pitch angles ranging from about 7{deg} to 20{deg}. The widths of spiral arms increase with distance from the Galactic center. Fitting axially symmetric models of the Milky Way with the three-dimensional position and velocity information and conservative priors for the solar and average source peculiar motions, we estimate the distance to the Galactic center, R_0_, to be 8.34+/-0.16kpc, a circular rotation speed at the Sun, {Theta}_0_, to be 240+/-8km/s, and a rotation curve that is nearly flat (i.e., a slope of -0.2+/-0.4km/s/kpc) between Galactocentric radii of {approx}5 and 16kpc. Assuming a "universal" spiral galaxy form for the rotation curve, we estimate the thin disk scale length to be 2.44+/-0.16kpc. With this large data set, the parameters R_0_ and {Theta}_0_are no longer highly correlated and are relatively insensitive to different forms of the rotation curve. If one adopts a theoretically motivated prior that high-mass star forming regions are in nearly circular Galactic orbits, we estimate a global solar motion component in the direction of Galactic rotation, V_{sun}_=14.6+/-5.0km/s. While {Theta}_0_and V_{sun}_are significantly correlated, the sum of these parameters is well constrained, {Theta}_0_+V_{sun}_=255.2+/-5.1km/s, as is the angular speed of the Sun in its orbit about the Galactic center, ({Theta}_0_+V_{sun}_)/R_0_=30.57+/-0.43km/s/kpc. These parameters improve the accuracy of estimates of the accelerations of the Sun and the Hulse-Taylor binary pulsar in their Galactic orbits, significantly reducing the uncertainty in tests of gravitational radiation predicted by general relativity.
1217. Parameters of protoplanetary disks in 5 SFRs
ID:
ivo://CDS.VizieR/J/ApJ/899/55
Title:
Parameters of protoplanetary disks in 5 SFRs
Short Name:
J/ApJ/899/55
Date:
14 Mar 2022 07:11:43
Publisher:
CDS
Description:
Spatial correlations among protoplanetary disk orientations carry unique information on physics of multiple-star formation processes. We select five nearby star-forming regions that comprise a number of protoplanetary disks with spatially resolved images with ALMA and Hubble Space Telescope, and we search for the mutual alignment of the disk axes. Specifically, we apply the Kuiper test to examine the statistical uniformity of the position angle (PA: the angle of the major axis of the projected disk ellipse measured counterclockwise from the north) distribution. The disks located in the star-forming regions, except the Lupus clouds, do not show any signature of the alignment, supporting the random orientation. Rotational axes of 16 disks with spectroscopic measurement of PA in the LupusIII cloud, a subregion of the Lupus field, however, exhibit a weak and possible departure from the random distribution at a 2{sigma} level, and the inclination angles of the 16 disks are not uniform as well. Furthermore, the mean direction of the disk PAs in the LupusIII cloud is parallel to the direction of its filament structure and approximately perpendicular to the magnetic field direction. We also confirm the robustness of the estimated PAs in the Lupus clouds by comparing the different observations and estimators based on three different methods, including sparse modeling. The absence of the significant alignment of the disk orientation is consistent with the turbulent origin of the disk angular momentum. Further observations are required to confirm/falsify the possible disk alignment in the Lupus III cloud.
1218. Parameters of radio sources near Sgr A*
ID:
ivo://CDS.VizieR/J/ApJ/801/L26
Title:
Parameters of radio sources near Sgr A*
Short Name:
J/ApJ/801/L26
Date:
21 Oct 2021
Publisher:
CDS
Description:
We present radio images within 30" of Sgr A* based on recent VLA observations at 34 GHz with 7.8 {mu}Jy sensitivity and resolution of ~88x46 mas. We report 44 partially resolved compact sources clustered in two regions in the E arm of ionized gas that orbits Sgr A*. These sources have size scales ranging between ~50 and 200 mas (400-1600 AUs), and a bow-shock appearance facing the direction of Sgr A*. Unlike the bow-shock sources previously identified in the near-IR but associated with massive stars, these 34 GHz sources do not appear to have near-IR counterparts at 3.8 {mu}m. We interpret these sources as a candidate population of photoevaporative protoplanetary disks (proplyds) that are associated with newly formed low mass stars with mass loss rates ~10^-7^-10^-6^ M_{sun}_/yr and are located at the edge of a molecular cloud outlined by ionized gas. The disks are externally illuminated by strong Lyman continuum radiation from the ~100 OB and WR massive stars distributed within 10" of Sgr A*. The presence of proplyds implies current in situ star formation activity near Sgr A* and opens a window for the first time to study low mass star, planetary, and brown dwarf formations near a supermassive black hole. The video abstract was created from a WorldWide Telescope tour file, which is available for download. Viewing the file requires a Windows PC with the WorldWide Telescope desktop client available at worldwidetelescope.org.
1219. Parkes Half-Jansky Flat-Spectrum Sample
ID:
ivo://CDS.VizieR/VIII/34
Title:
Parkes Half-Jansky Flat-Spectrum Sample
Short Name:
VIII/34
Date:
21 Oct 2021
Publisher:
CDS
Description:
We present a new sample of Parkes half-Jansky flat-spectrum radio sources having made a particular effort to find any previously unidentified sources. The sample contains 323 sources selected according to a flux limit of 0.5 Jy at 2.7 GHz, a spectral index measured between 2.7 and 5.0 GHz of {alpha}(2.7/5.0) > -0.5, where S(f) is proportional to f^alpha^, Galactic latitude |b| > 20{deg} and -45{deg} < Declination(B1950) < +10{deg}. The sample was selected from a region 3.90 steradians in area. We have obtained accurate radio positions for all the unresolved sources in this sample and combined these with accurate optical positions from digitised photographic sky survey data to check all the optical identifications. We report new identifications based on R- and Kn-band imaging and new spectroscopic measurements of many of the sources. We present a catalogue of the 323 sources of which 321 now have identified optical counterparts and 277 have measured spectral redshifts.
1220. Parkes High-Latitude H I Survey
ID:
ivo://CDS.VizieR/VIII/8A
Title:
Parkes High-Latitude H I Survey
Short Name:
VIII/8A
Date:
21 Oct 2021
Publisher:
CDS
Description:
This survey consists of HI 21-cm spectra covering the southern sky with absolute galactic latitude |b|>=10 degrees and declination dec<=-30 degrees. The observations were made with the Parkes Radio Observatory (CSIRO) 60-foot telescope. The receiver back end was the Parkes 64-channel spectrometer. The velocity resolution was 7km/s (33kHz) and the beamwidth (HPBW) was 48arcmin. Drift scans at constant declination were used with continuous integration in right ascension for -80<=declination<=-30 degrees. For declination<-80 degrees a grid of positions spaced 1 degree apart in declination and one beam-width apart in right ascension were observed. The survey was made in two parts. Part 1 included b>=-25 degrees, |b|>=10 degrees and declination dec<=-30 degrees. Part 2 included b<=-25 degrees and dec<=-30 degrees. The scans in Part 1 were spaced at 1 degree intervals in declination and the velocity coverage was from -148 to +300km/s. The scans in Part 2 were spaced at 2 degrees and the velocity coverage was from -230 to +218km/s. Each spectrum or record consists of a header followed by 64 antenna temperatures. The header contains the galactic longitude, galactic latitude, right ascension, declination, central velocity (LSR), and quality factor. The catalog contains a total of 9891 spectra.