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1251. Planetary Nebulae in NRAO VLA Sky Survey
ID:
ivo://CDS.VizieR/J/ApJS/123/219
Title:
Planetary Nebulae in NRAO VLA Sky Survey
Short Name:
J/ApJS/123/219
Date:
21 Oct 2021
Publisher:
CDS
Description:
In order to construct a sample of planetary nebulae (PNe) unbiased by dust extinction, we first selected the 1358 sources in the IRAS Point Source Catalog north of J2000 declination DE=-40{deg} having measured S(25{mu}m)>=1 Jy and colors characteristic of PNe: detections or upper limits consistent with both S(12{mu}m)<=0.35S(25{mu}m) and S(25{mu}m)>=0.35S(60{mu}m). The majority are radio-quiet contaminating sources such as asymptotic giant branch stars. Free-free emission from genuine PNe should make them radio sources. The 1.4 GHz NRAO VLA Sky Survey (NVSS) images and source catalog were used to reject radio-quiet mid-infrared sources. We identified 454 IRAS sources with radio sources brighter than S~2.5 mJy/beam (equivalent to T~0.8K in the 45" FHWM NVSS beam) by positional coincidence. They comprise 332 known PNe in the Strasbourg-ESO Catalogue of Galactic Planetary Nebulae and 122 candidate PNe, most of which lie at very low Galactic latitudes. Exploratory optical spectroscopic observations suggest that most of these candidates are indeed PNe optically dimmed by dust extinction, although some contamination remains from H II regions, Seyfert galaxies, etc. Furthermore, the NVSS failed to detect only 4% of the known PNe in our infrared sample. Thus it appears that radio selection can greatly improve the reliability of PN candidate samples without sacrificing completeness.
1252. PMN J0948+0022 radio-to-gamma-ray monitoring
ID:
ivo://CDS.VizieR/J/A+A/548/A106
Title:
PMN J0948+0022 radio-to-gamma-ray monitoring
Short Name:
J/A+A/548/A106
Date:
21 Oct 2021
Publisher:
CDS
Description:
We present more than three years of observations at different frequencies, from radio to high-energy gamma-rays, of the Narrow-Line Seyfert 1 (NLS1) Galaxy PMN J0948+0022 (z=0.585). This source is the first NLS1 detected at energies above 100 MeV and therefore can be considered the prototype of this emerging new class of gamma-ray emitting active galactic nuclei (AGN). The observations performed from 2008 August 1 to 2011 December 31 confirmed that PMN J0948+0022 generates a powerful relativistic jet, able to develop an isotropic luminosity at gamma-rays of the order of 10^48^erg/s, at the level of powerful quasars. The evolution of the radiation emission of this source in 2009 and 2010 followed the canonical expectations of relativistic jets, with correlated multiwavelength variability (gamma-rays followed by radio emission after a few months), but it was difficult to retrieve a similar pattern in the light curves of 2011. The comparison of gamma-ray spectra before and including 2011 data suggested that there was a softening of the high-energy spectral slope. We selected five specific epochs to be studied by modelling the broad-band spectrum, characterised by an outburst at gamma-rays or very low/high flux at other wavelengths. The observed variability can largely be explained either by changes in the injected power, the bulk Lorentz factor of the jet or the electron spectrum. The characteristic time scale of doubling/halving flux ranges from a few days to a few months, depending on the frequency and the sampling rate. The shortest doubling time scale at gamma-rays is 2.3+/-0.5days. These small values underline the need of highly-sampled multiwavelength campaigns to better understand the physics of these sources.
1253. PMN map catalog of radiosources
ID:
ivo://CDS.VizieR/J/ApJS/90/173
Title:
PMN map catalog of radiosources
Short Name:
J/ApJS/90/173
Date:
21 Oct 2021
Publisher:
CDS
Description:
The Parkes-MIT-NRAO (PMN) southern survey was made with the NRAO 4.85GHz seven-beam receiver on the Parkes 64 m telescope during 1990 June, and maps covering the Omega = 2.5 sr declination band -88{deg}<Dec.<-37{deg} were constructed from the survey scans. We present a catalog of 15,045 discrete sources with angular sizes phi<~15arcmin and stronger than S~25mJy derived from these maps. Machine-readable versions of the catalog with either B1950 or J2000 positions, and a printed catalog with B1950 positions only, are available. The 4.85GHz weighted source counts S^(5/2)^n(S) between 30mJy and 10Jy were obtained and agree well with previous results.
1254. PNe angular diameters from SED modeling
ID:
ivo://CDS.VizieR/J/MNRAS/503/2887
Title:
PNe angular diameters from SED modeling
Short Name:
J/MNRAS/503/2887
Date:
21 Oct 2021
Publisher:
CDS
Description:
Powerful new, high-resolution, high-sensitivity, multifrequency, wide-field radio surveys such as the Australian Square Kilometre Array Pathfinder (ASKAP) Evolutionary Map of the Universe are emerging. They will offer fresh opportunities to undertake new determinations of useful parameters for various kinds of extended astrophysical phenomena. Here, we consider specific application to angular-size determinations of Planetary Nebulae (PNe) via a new radio continuum spectral energy distribution fitting technique. We show that robust determinations of angular size can be obtained, comparable to the best optical and radio observations but with the potential for consistent application across the population. This includes unresolved and/or heavily obscured PNe that are extremely faint or even non-detectable in the optical.
1255. PNe in NRAO VLA Sky Survey
ID:
ivo://CDS.VizieR/J/ApJS/117/361
Title:
PNe in NRAO VLA Sky Survey
Short Name:
J/ApJS/117/361
Date:
21 Oct 2021
Publisher:
CDS
Description:
The 1.4GHz NRAO VLA Sky Survey (NVSS) images and source catalog were used to detect radio emission from the 885 planetary nebulae north of J2000 declination {delta}=-40{deg} in the Strasbourg-ESO Catalogue of Galactic Planetary Nebulae (Cat. <V/84>). We identified 680 radio sources brighter than about S=2.5mJy/beam (equivalent to T~0.8K in the 45" FWHM NVSS beam) with planetary nebulae by coincidence with accurate optical positions measured from Digitized Sky Survey (DSS) images. Total extinction coefficients c at {lambda}=4861{AA} were calculated for the 429 planetary nebulae with available H{beta} fluxes and low free-free optical depths at 1.4GHz. The variation of c with Galactic latitude and longitude is consistent with the extinction being primarily interstellar and not intrinsic.
1256. POETS luminous YSOs 13 or 22GHz images
ID:
ivo://CDS.VizieR/J/A+A/631/A74
Title:
POETS luminous YSOs 13 or 22GHz images
Short Name:
J/A+A/631/A74
Date:
21 Oct 2021
Publisher:
CDS
Description:
Although recent observations and theoretical simulations have pointed out that accretion disks and jets can be essential for the formation of stars with a mass of up to at least 20M_{sun}_, the processes regulating mass accretion and ejection are still uncertain. The goal of the Protostellar Outflows at the EarliesT Stages (POETS) survey is to image the disk-outflow interface on scales of 10-100au in a statistically significant sample (36) of luminous young stellar objects (YSO), targeting both the molecular and ionized components of the outflows. The outflow kinematics is studied at milliarcsecond scales through very long baseline interferometry (VLBI) observations of the 22GHz water masers, which are ideal test particles to measure the three-dimensional (3D) motion of shocks owing to the interaction of winds and jets with ambient gas. We employed the Jansky Very Large Array (JVLA) at 6, 13, and 22GHz in the Aand B-Array configurations to determine the spatial structure and the spectral index of the radio continuum emission, and address its nature. In about half of the targets, the water masers observed at separation <=1000au from the YSOs trace either or both of these kinematic structures: 1) a spatially elongated distribution oriented at close angle with the direction of collimation of the maser proper motions (PM), and 2) a linear local standard of rest (LSR) velocity (VLSR) gradient across the YSO position. The kinematic structure (1) is readily interpreted in terms of a protostellar jet, as confirmed in some targets via the comparison with independent observations of the YSO jets, in thermal (continuum and line) emissions, reported in the literature. The kinematic structure (2) is interpreted in terms of a disk-wind (DW) seen almost edge-on on the basis of several pieces of evidence: first, it is invariably directed perpendicular to the YSO jet; second, it agrees in orientation and polarity with the VLSR gradient in thermal emissions (when reported in the literature) identifying the YSO disk at scales of <=1000au; third, the PMs of the masers delineating the VLSR gradients hint at flow motions at a speed of 10-20km/s directed at large angles with the disk midplane. In the remaining targets, the maser PMs are not collimated but rather tend to align along two almost perpendicular directions. To explain this peculiar PM distribution, and in light of the observational bias strongly favoring masers moving close to the plane of sky, we propose that, in these sources, the maser emission could originate in DW-jet systems slightly inclined (<=30{deg}) with respect to edge-on. Magneto-centrifugally driven DWs could in general account for the observed velocity patterns of water masers.
1257. POGS-II ExGal catalog
ID:
ivo://CDS.VizieR/J/other/PASA/37.29
Title:
POGS-II ExGal catalog
Short Name:
J/other/PASA/37.
Date:
21 Oct 2021
Publisher:
CDS
Description:
The low-frequency linearly polarised radio source population is largely unexplored. However, a renaissance in low-frequency polarimetry has been enabled by pathfinder and precursor instruments for the Square Kilometre Array. In this second paper from the POlarised GaLactic and Extragalactic All-Sky MWA Survey-the POlarised GLEAM Survey, or POGS-we present the results from our all-sky MWA Phase I Faraday Rotation Measure survey. Our survey covers nearly the entire Southern sky in the Declination range -82{deg} to +30{deg} at a resolution between around three and seven arcminutes (depending on Declination) using data in the frequency range 169-231MHz. We have performed two targeted searches: the first covering 25489 square degrees of sky, searching for extragalactic polarised sources; the second covering the entire sky South of Declination +30{deg}, searching for known pulsars. We detect a total of 517 sources with 200MHz linearly polarised flux densities between 9.9mJy and 1.7Jy, of which 33 are known radio pulsars. All sources in our catalogues have Faraday rotation measures in the range -328.07rad/m^2^ to +279.62rad/m^2^. The Faraday rotation measures are broadly consistent with results from higher-frequency surveys, but with typically more than an order of magnitude improvement in the precision, highlighting the power of low-frequency polarisation surveys to accurately study Galactic and extragalactic magnetic fields. We discuss the properties of our extragalactic and known-pulsar source population, how the sky distribution relates to Galactic features, and identify a handful of new pulsar candidates among our nominally extragalactic source population.
1258. Polarimetry of 600 pulsars from 1.4GHz obs.
ID:
ivo://CDS.VizieR/J/MNRAS/474/4629
Title:
Polarimetry of 600 pulsars from 1.4GHz obs.
Short Name:
J/MNRAS/474/4629
Date:
21 Oct 2021
Publisher:
CDS
Description:
Over the past 13yr, the Parkes radio telescope has observed a large number of pulsars using digital filter bank backends with high time and frequency resolution and the capability for Stokes recording. Here, we use archival data to present polarimetry data at an observing frequency of 1.4GHz for 600 pulsars with spin-periods ranging from 0.036 to 8.5s. We comment briefly on some of the statistical implications from the data and highlight the differences between pulsars with high and low spin-down energy. The data set, images and table of properties for all 600 pulsars are made available in a public data archive maintained by the CSIRO.
1259. Polarisation at 850mu{m} in OMC-2 and OMC-3
ID:
ivo://CDS.VizieR/J/ApJ/716/893
Title:
Polarisation at 850mu{m} in OMC-2 and OMC-3
Short Name:
J/ApJ/716/893
Date:
21 Oct 2021
Publisher:
CDS
Description:
The SCUBA polarized 850um thermal emission data of the OMC-2 region in Orion A are added to and homogeneously reduced with data already available in the OMC-3 region. The data set shows that OMC-2 is a region generally less polarized than OMC-3. Where coincident, most of the 850um polarization pattern is similar to that measured in 350um polarization data. Only 850um polarimetry data have been obtained in and around MMS7, FIR1 and FIR2, and in the region south of FIR6. A realignment of the polarization vectors with the filament can be seen near FIR1 in the region south of OMC-3. An analysis shows that the energy injected by CO outflows and H2 jets associated with OMC-2 and OMC-3 does not appear to alter the polarization patterns at a scale of the 14" resolution beam. A second-order structure function analysis of the polarization position angles shows that OMC-2 is a more turbulent region than OMC-3. OMC-3 appears to be a clear case of a magnetically dominated region with respect to the turbulence. However, for OMC-2 it is not clear that this is the case. A more in-depth analysis of five regions displayed along OMC-2/3 indicates a decrease of the mean polarization degree and an increase of the turbulent angular dispersion from north to south. A statistical analysis suggests the presence of two depolarization regimes in our maps: one regime including the effects of the cores, the other one excluding it.
1260. Polarisation of flat-spectrum radio sources
ID:
ivo://CDS.VizieR/J/MNRAS/376/371
Title:
Polarisation of flat-spectrum radio sources
Short Name:
J/MNRAS/376/371
Date:
21 Oct 2021
Publisher:
CDS
Description:
We have used the very large JVAS/CLASS 8.4GHz surveys of flat-spectrum radio sources to obtain a large, uniformly observed and calibrated, sample of radio source polarizations. These are useful for many investigations of the properties of radio sources and the interstellar medium. We discuss comparisons with polarization measurements from this survey and from other large-scale surveys of polarization in flat-spectrum sources.