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531. FRBCAT: The Fast Radio Burst (FRB) Catalog
ID:
ivo://CDS.VizieR/J/other/PASA/33.45
Title:
FRBCAT: The Fast Radio Burst (FRB) Catalog
Short Name:
J/other/PASA/33.
Date:
06 Dec 2021 20:29:39
Publisher:
CDS
Description:
Here, we present a catalogue of known Fast Radio Burst sources in the form of an online catalogue, FRBCAT. The catalogue includes information about the instrumentation used for the observations for each detected burst, the measured quantities from each observation, and model-dependent quantities derived from observed quantities. To aid in consistent comparisons of burst properties such as width and signal-to-noise ratios, we have re-processed all the bursts for which we have access to the raw data, with software which we make available. The originally derived properties are also listed for comparison.
532. FRII radio sources dynamical models
ID:
ivo://CDS.VizieR/J/ApJS/255/22
Title:
FRII radio sources dynamical models
Short Name:
J/ApJS/255/22
Date:
03 Dec 2021 13:25:10
Publisher:
CDS
Description:
Dynamical evolution models of 361 extragalactic Fanaroff-Riley type II radio sources selected from the Cambridge 3CRR, 6CE, 5C6, and 5C7 Sky Surveys, as well as the Bologna B2, Green Bank GB, and GB2 Surveys, are presented. Their spectra, compiled mostly from the recent catalogs of radio sources and the available NASA/IPAC and Astrophysical Catalogs Support System databases, along with morphological characteristics of the sources determined from their radio maps, have been modeled using the DYNAGE algorithm and/or its extension (KDA EXT) for the hypothetical case of further evolution after the jet's termination. The best-fit models provide estimates of a number of important physical parameters of the sources, as (i) the jet power, (ii) the density distribution of the external gaseous medium surrounding the radio core and the jet propagating through it, (iii) the initial energy distribution of the relativistic particles accelerated at the shock fronts, and (iv) the age of the observed radio structure. Additionally, estimates of some derivative parameters are provided, e.g., the radio lobes' pressure, their longitudinal expansion velocity, the magnetic field strength, and the total energy deposited in the lobes. The observed spectra and their best-fit models are included. Finally, one of the useful applications of the above models is presented, namely a strong correlation between the ambient medium density and the rest-frame two-point spectral index available directly from the observed spectra.
533. Full-polarization observations of OH masers
ID:
ivo://CDS.VizieR/J/ApJS/160/220
Title:
Full-polarization observations of OH masers
Short Name:
J/ApJS/160/220
Date:
21 Oct 2021
Publisher:
CDS
Description:
We present full-polarization VLBA maps of the ground-state, main-line, ^2^{Pi}_3/2_, J=3/2 OH masers in 18 Galactic massive star-forming regions. This is the first large polarization survey of interstellar hydroxyl masers at VLBI resolution. A total of 184 Zeeman pairs are identified, and the corresponding magnetic field strengths are indicated. We also present spectra of the NH_3_ emission or absorption in these star-forming regions.
534. Full-Stokes polarimetry of 5 radio sources
ID:
ivo://CDS.VizieR/J/A+A/609/A68
Title:
Full-Stokes polarimetry of 5 radio sources
Short Name:
J/A+A/609/A68
Date:
21 Oct 2021
Publisher:
CDS
Description:
We present an analysis pipeline that enables the recovery of reliable information for all four Stokes parameters with high accuracy. Its novelty relies on the effective treatment of the instrumental effects even before the computation of the Stokes parameters, contrary to conventionally used methods such as that based on the Mueller matrix. For instance, instrumental linear polarization is corrected across the whole telescope beam and significant Stokes Q and U can be recovered even when the recorded signals are severely corrupted by instrumental effects. The accuracy we reach in terms of polarization degree is of the order of 0.1-0.2%. The polarization angles are determined with an accuracy of almost 1{def}. The presented methodology was applied to recover the linear and circular polarization of around 150 active galactic nuclei, which were monitored between July 2010 and April 2016 with the Effelsberg 100-m telescope at 4.85GHz and 8.35GHz with a median cadence of 1.2 months. The polarized emission of the Moon was used to calibrate the polarization angle measurements. Our analysis showed a small system-induced rotation of about 1{deg} at both observing frequencies. Over the examined period, five sources have significant and stable linear polarization; three sources remain constantly linearly unpolarized; and a total of 11 sources have stable circular polarization degree m_c_, four of them with non-zero m_c_. We also identify eight sources that maintain a stable polarization angle. All this is provided to the community for future polarization observations reference. We finally show that our analysis method is conceptually different from those traditionally used and performs better than the Mueller matrix method. Although it has been developed for a system equipped with circularly polarized feeds, it can easily be generalized to systems with linearly polarized feeds as well.
535. G24.78+0.08 A1 ALMA images and datacubes
ID:
ivo://CDS.VizieR/J/A+A/650/A142
Title:
G24.78+0.08 A1 ALMA images and datacubes
Short Name:
J/A+A/650/A142
Date:
22 Feb 2022
Publisher:
CDS
Description:
Hyper-compact (HC) or ultra-compact HII regions are the first manifestations of the radiation feedback from a newly born massive star. Therefore, their study is fundamental to understanding the process of massive (>=8M_{sun}_) star formation. We employed Atacama Large Millimeter/submillimeter Array (ALMA) 1.4mm Cycle 6 observations to investigate at high angular resolution (~0.050, corresponding to 330au) the HC HII region inside molecular core A1 of the high-mass star-forming cluster G24.78+0.08. We used the H30{alpha} emission and different molecular lines of CH_3_CN and ^13^CH_3_CN to study the kinematics of the ionized and molecular gas, respectively. At the center of the HC HII region, at radii <~500au, we observe two mutually perpendicular velocity gradients, which are directed along the axes at PA=39{deg} and PA=133{deg}, respectively. The velocity gradient directed along the axis at PA=39{deg} has an amplitude of 22km/s/mpc, which is much larger than the other;s, 3km/s/mpc. We interpret these velocity gradients as rotation around, and expansion along, the axis at PA=39{deg}. We propose a scenario where the H30{alpha} line traces the ionized heart of a disk-jet system that drives the formation of the massive star (~20M_{sun}_) responsible for the HC HII region. Such a scenario is also supported by the position-velocity plots of the CH_3_CN and ^13^CH_3_CN lines along the axis at PA=133{deg}, which are consistent with Keplerian rotation around a 20M_{sun}_ star. Toward the HC HII region in G24.78+0.08, the coexistence of mass infall (at radii of ~5000au), an outer molecular disk (from <~4000 au to >~500au), and an inner ionized disk (<~500au) indicates that the massive ionizing star is still actively accreting from its parental molecular core. To our knowledge, this is the first example of a molecular disk around a high-mass forming star that, while becoming internally ionized after the onset of the HII region, continues to accrete mass onto the ionizing star.
536. GaLactic and Extragalactic All-sky MWA survey
ID:
ivo://CDS.VizieR/VIII/100
Title:
GaLactic and Extragalactic All-sky MWA survey
Short Name:
VIII/100
Date:
21 Oct 2021
Publisher:
CDS
Description:
Using the Murchison Widefield Array (MWA), the low-frequency Square Kilometre Array (SKA1 LOW) precursor located in Western Australia, we have completed the GaLactic and Extragalactic All-sky MWA (GLEAM) survey, and present the resulting extragalactic catalogue, utilising the first year of observations. The catalogue covers 24,402 square degrees, over declinations south of +30{deg} and Galactic latitudes outside 10{deg} of the Galactic plane, excluding some areas such as the Magellanic Clouds. It contains 307,456 radio sources with 20 separate flux density measurements across 72-231MHz, selected from a time- and frequency- integrated image centred at 200MHz, with a resolution of ~=2'. Over the catalogued region, we estimate that the catalogue is 90% complete at 170mJy, and 50% complete at 55mJy, and large areas are complete at even lower flux density levels. Its reliability is 99.97% above the detection threshold of 5{sigma}, which itself is typically 50mJy. These observations constitute the widest fractional bandwidth and largest sky area survey at radio frequencies to date, and calibrate the low frequency flux density scale of the southern sky to better than 10%. This paper presents details of the flagging, imaging, mosaicking, and source extraction/characterisation, as well as estimates of the completeness and reliability. All source measurements and images are available online. This is the first in a series of publications describing the GLEAM survey results.
537. Galactic Bulge Region OH 1612MHz survey. I.
ID:
ivo://CDS.VizieR/J/A+AS/122/79
Title:
Galactic Bulge Region OH 1612MHz survey. I.
Short Name:
J/A+AS/122/79
Date:
21 Oct 2021
Publisher:
CDS
Description:
We present observations of the region between |l|<=10{deg} and |b|<=3{deg} in the OH 1612.231MHz line, taken in 1993 October and November with the Australia Telescope Compact Array. The region was systematically searched for OH/IR stars and was covered completely with 539 pointing centres separated by 30'. The size of the dataset calls for a special reduction technique that is fast, reliable and minimizes the output (positions and velocities of possible stars only). Having developed such a reduction method we found 307 OH masing objects, 145 of which are new detections. Out of these, 248 have a standard double-peaked spectral profile, 55 a single-peaked profile and 4 have nonstandard or irregular profiles. In this article we analyse the data statistically and give classifications and identifications with known sources where possible. The astrophysical, kinematical, morphological and dynamical properties of subsets of the data will be addressed in future articles. These observations are part of a larger survey, covering |l|<=45{deg} and |b|<=3{deg}, with the Australia Telescope Compact Array and the Very Large Array. The electronic version of this paper, that includes table and spectra, can be obtained from http://www.ed-phys.fr.
538. Galactic Center 6 and 20cm survey
ID:
ivo://CDS.VizieR/J/ApJS/118/201
Title:
Galactic Center 6 and 20cm survey
Short Name:
J/ApJS/118/201
Date:
21 Oct 2021
Publisher:
CDS
Description:
We have used the VLA to survey 10 fields at 20 cm (1658MHz) and 11 fields at 6 cm (5GHz) that are between 7' and 137' from SgrA*. Our objective was to identify extragalactic sources and measure their scattering diameters so as to constrain the GC-scattering region separation. In order to find sources within these fields, we have employed pdfCLEAN, a source detection algorithm in which sources are identified in an image by comparing the intensity histogram of the image to that expected from a noise-only image. We found over 100 sources, with the faintest sources being approximately 3 mJy. The average number of sources per field is approximately 10, though fields close to SgrA* tend to contain fewer sources. A number of Galactic sources are included in our source catalog. The double-lobed source 1LC 359.872+0.178, potentially an X-ray quiet version of 1E 1740.7-2942, a shell-like structure with a central point source, and a possible radio transient, are discussed in the paper.
539. Galactic CHaMP. III. ^12^CO dense clump properties
ID:
ivo://CDS.VizieR/J/ApJ/831/67
Title:
Galactic CHaMP. III. ^12^CO dense clump properties
Short Name:
J/ApJ/831/67
Date:
21 Oct 2021
Publisher:
CDS
Description:
We report the second complete molecular line data release from the Census of High- and Medium-mass Protostars (CHaMP), a large-scale, unbiased, uniform mapping survey at sub-parsec resolution, of millimeter-wave line emission from 303 massive, dense molecular clumps in the Milky Way. This release is for all ^12^CO J=1->0 emission associated with the dense gas, the first from Phase II of the survey, which includes ^12^CO, ^13^CO, and C^18^O. The observed clump emission traced by both ^12^CO and HCO^+^ (from Phase I) shows very similar morphology, indicating that, for dense molecular clouds and complexes of all sizes, parsec-scale clumps contain {Xi}~75% of the mass, while only 25% of the mass lies in extended (>~10pc) or "low density" components in these same areas. The mass fraction of all gas above a density of 10^9^m^-3^ is {xi}_9_>~50%. This suggests that parsec-scale clumps may be the basic building blocks of the molecular interstellar medium, rather than the standard giant molecular cloud (GMC) concept. Using ^12^CO emission, we derive physical properties of these clumps in their entirety, and compare them to properties from HCO^+^, tracing their denser interiors. We compare the standard X-factor converting I_^12^CO_ to N_H2_ with alternative conversions, and show that only the latter give whole-clump properties that are physically consistent with those of their interiors. We infer that the clump population is systematically closer to virial equilibrium than when considering only their interiors, with perhaps half being long-lived (10s of Myr), pressure-confined entities that only terminally engage in vigorous massive star formation, supporting other evidence along these lines that was previously published.
540. Galactic emission at decimeter wavelengths
ID:
ivo://CDS.VizieR/J/A+A/410/847
Title:
Galactic emission at decimeter wavelengths
Short Name:
J/A+A/410/847
Date:
21 Oct 2021
Publisher:
CDS
Description:
The diffuse galactic emission maps at decimeter wavelengths (408 MHz, Haslam et al., 1982A&AS...47....1H), (1420 MHz, Reich, 1982A&AS...48..219R, Reich & Reich 1986A&AS...63..205R), (2326 MHz, Jonas et al., 1998MNRAS.297..977J) have been destriped using the method proposed by Schlegel et al., 1998ApJ...500..525S. Statistical and systematic errors have been evaluated for each map. Each map is presented in two different pixelizations: ECP (Cartesian Projection) and HEALPix. In the case of HEALPix pixelization (in which the pixel area is constant), we omitted the (constant) error maps; the statistical and systematic errors for each map are summarized in the "Table 2" section below. Synchrotron spectral index and normalization factor have been evaluated using the three destriped surveys. Some of the results in this work have been derived using the HEALPix (Gorski et al., 1999, Proceedings of the MPA/ESO Conference on Evolution of Large-Scale Structure: from Recombination to Garching, ed. A.J. Banday, R.K. Sheth, & L. Da Costa, 37).