- 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.
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- 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.
- 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.
- 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.
- ID:
- ivo://CDS.VizieR/J/A+A/505/1049
- Title:
- Parkes HI observations behind Milky Way II
- Short Name:
- J/A+A/505/1049
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- As part of our programme to map the large-scale distribution of galaxies behind the southern Milky Way, we observed 314 optically-selected, partially-obscured galaxies in the Zone of Avoidance (ZOA) in the Crux and Great Attractor (GA) regions. An additional 29 galaxies were observed in the Vela ZOA survey region (because of the small numbers they are not discussed any further). The observations were conducted with the Parkes 64m (210 ft) radio telescope, in a single-pixel pointed mode, reaching an rms noise level of typically 2-6mJy over the velocity search range of 400<v<10500km/s. A total of 162 galaxies were detected (plus 14 galaxies in the Vela region). The detection rate is slightly higher than for the Hydra/Antlia region (52% versus 45%) observed in the same way.
- ID:
- ivo://CDS.VizieR/J/MNRAS/342/1299
- Title:
- Parkes Multi-Beam Pulsar Survey. III.
- Short Name:
- J/MNRAS/342/1299
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The Parkes Multibeam Pulsar Survey has unlocked vast areas of the Galactic plane, which were previously invisible to earlier low-frequency and less-sensitive surveys. The survey has discovered more than 600 new pulsars so far, including many that are young and exotic. In this paper we report the discovery of 200 pulsars for which we present positional and spin-down parameters, dispersion measures, flux densities and pulse profiles. A large number of these new pulsars are young and energetic, and we review possible associations of {gamma}-ray sources with the sample of about 1300 pulsars for which timing solutions are known. Based on a statistical analysis, we estimate that about 19+/-6 associations are genuine. The survey has also discovered 12 pulsars with spin properties similar to those of the Vela pulsar, nearly doubling the known population of such neutron stars. Studying the properties of all known 'Vela-like' pulsars, we find their radio luminosities to be similar to normal pulsars, implying that they are very inefficient radio sources. Finally, we review the use of the newly discovered pulsars as Galactic probes and discuss the implications of the new NE2001 Galactic electron density model for the determination of pulsar distances and luminosities.
- ID:
- ivo://CDS.VizieR/J/MNRAS/335/275
- Title:
- Parkes Multi-Beam Pulsar Survey new PSR
- Short Name:
- J/MNRAS/335/275
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The Parkes Multibeam Pulsar Survey is a sensitive survey of a strip of the Galactic plane with |b|<5{deg} and 260{deg}<l<50{deg} at 1374MHz. Here we report the discovery of 120 new pulsars and subsequent timing observations, primarily using the 76-m Lovell radio telescope at Jodrell Bank. The main features of the sample of 370 published pulsars discovered during the multibeam survey are described. Furthermore, we highlight two pulsars: PSR J1734-3333, a young pulsar with the second highest surface magnetic field strength among the known radio pulsars, B_S_=5.4x10^13^G, and PSR J1830-1135, he second slowest radio pulsar known, with a 6-s period.
- ID:
- ivo://CDS.VizieR/VIII/15
- Title:
- Parkes Radio Sources Catalogue (PKSCAT90)
- Short Name:
- VIII/15
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- PKSCAT90 consists of radio and optical data for 8264 radio sources. It covers essentially all the sky south of declination +27 degrees but largely excludes the Galactic Plane and the Magellanic Cloud regions. The latter zones have been the subject of other, specialist surveys. A few data errors in Version 1.00 have been corrected in the present edition. This version of the Parkes Radio source Catalogue entitled "PKSCAT90 Version 1.01" is intended for use on IBM PC-type machines.
- ID:
- ivo://CDS.VizieR/J/other/PASAu/10.310
- Title:
- Parkes-Tidbinbilla radio sources
- Short Name:
- J/other/PASAu/10
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We have measured the 2.3GHz total and correlated flux densities on a baseline of 275km of all sources in the Parkes catalogue which : (i) are south of declination +10deg, (ii) have a catalogued 2.7GHz total flux density exceeding 0.5Jy, and (iii) have a 2.7/5.0GHz spectral index flatter than -0.5. More than 14% of the sample showed visibility amplitudes greater than 0.9, and more than 72% showed visibility amplitudes greater than 0.5. Of the sources with optical or other identifications 79% were quasars. In this paper we briefly summarise the results of this survey.
- ID:
- ivo://CDS.VizieR/J/MNRAS/274/324
- Title:
- Penticton observations at 408 and 1420MHz
- Short Name:
- J/MNRAS/274/324
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present results from radio continuum observations of two fields made at 408 and 1420MHz with the DRAO Synthesis Telescope. Two sets of data, one year apart, were obtained of each field, and here we present source lists from the average 408-MHz images, and from the second-epoch 1420-MHz images. Variability studies at 408MHz from these observations will be presented in a forthcoming paper.