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1721. The Serpens filament 13CO, C18O and C17O datacubes
ID:
ivo://CDS.VizieR/J/A+A/646/A170
Title:
The Serpens filament 13CO, C18O and C17O datacubes
Short Name:
J/A+A/646/A170
Date:
21 Oct 2021
Publisher:
CDS
Description:
The Serpens filament, a prominent elongated structure in a relatively nearby molecular cloud, is believed to be at an early evolutionary stage, so studying its physical and chemical properties can shed light on filament formation and early evolution. The main goal is to address the physical and chemical properties as well as dynamical state of the Serpens filament at a spatial resolution of ~0.07pc and a spectral resolution of ~0.1~km/s. We performed ^13^CO (1-0), C^18^O (1-0), C^17^O (1-0), ^13^CO (2-1), C^18^O (2-1), and C^17^O (2-1) imaging observations toward the Serpens filament with the IRAM-3 m and APEX telescopes. Widespread narrow ^13^CO (2-1) self-absorption is observed in this filament, causing the ^13^CO morphology to be different from the filamentary structure traced by C^18^O and C^17^O. Our excitation analysis suggests that the opacities of C^18^O transitions become higher than unity in most regions, and this analysis confirms the presence of widespread CO depletion. Further we show that the local velocity gradients have a tendency to be perpendicular to the filament's long axis in the outskirts and parallel to the large-scale magnetic field direction. The magnitudes of the local velocity gradients decrease toward the filament's crest. The observed velocity structure can be a result of gravity-driven accretion flows. The isochronic evolutionary track of the C^18^O freeze-out process indicates the filament is young with an age of <~2Myr. We propose that the Serpens filament is a newly-formed slightly-supercritical structure which appears to be actively accreting material from its ambient gas.
1722. The SPTpol Extended Cluster Survey
ID:
ivo://CDS.VizieR/J/ApJS/247/25
Title:
The SPTpol Extended Cluster Survey
Short Name:
J/ApJS/247/25
Date:
18 Jan 2022 14:48:55
Publisher:
CDS
Description:
We describe the observations and resultant galaxy cluster catalog from the 2770deg^2^ SPTpol Extended Cluster Survey (SPT-ECS). Clusters are identified via the Sunyaev-Zel'dovich (SZ) effect and confirmed with a combination of archival and targeted follow-up data, making particular use of data from the Dark Energy Survey (DES). With incomplete follow-up we have confirmed as clusters 244 of 266 candidates at a detection significance {xi}>=5 and an additional 204 systems at 4<{xi}<5. The confirmed sample has a median mass of M_500c_~4.4x10^14^M_{sun}_h_70_^-1^ and a median redshift of z=0.49, and we have identified 44 strong gravitational lenses in the sample thus far. Radio data are used to characterize contamination to the SZ signal; the median contamination for confirmed clusters is predicted to be ~1% of the SZ signal at the {xi}>4 threshold, and <4% of clusters have a predicted contamination >10% of their measured SZ flux. We associate SZ-selected clusters, from both SPT-ECS and the SPT-SZ survey, with clusters from the DES redMaPPer sample, and we find an offset distribution between the SZ center and central galaxy in general agreement with previous work, though with a larger fraction of clusters with significant offsets. Adopting a fixed Planck-like cosmology, we measure the optical richness-SZ mass ({lambda}-M) relation and find it to be 28% shallower than that from a weak-lensing analysis of the DES data-a difference significant at the 4{sigma} level-with the relations intersecting at {lambda}=60. The SPT-ECS cluster sample will be particularly useful for studying the evolution of massive clusters and, in combination with DES lensing observations and the SPT-SZ cluster sample, will be an important component of future cosmological analyses.
1723. The Third Bologna Survey (B3)
ID:
ivo://CDS.VizieR/VIII/37
Title:
The Third Bologna Survey (B3)
Short Name:
VIII/37
Date:
21 Oct 2021
Publisher:
CDS
Description:
This catalogue contains the first section of a sky survey performed at 408MHz with the 'Northern Cross' Radiotelescope. It contains about 13.000 radiosources. Although sources down to about 70mJy were measured, only sources brighter than 0.10Jy are retained in the catalogue. According to our estimate of confusion errors, this corresponds to a detection threshold of about 5{sigma}. The list is meant to include all the sources with a measured flux S>0.10Jy, in the sky area included between the declinations +37{deg}15' and +47{deg}37', epoch 1978.0. A number of zones however are affected by interferences, malfunctions, etc. The principal one is centered about the radiosource Cyg A, which is itself in the map, but not in the catalogue. The zone between RA 19h30m to 20h30m is entirely lacking, due to strong confusion. In the zone from 19h00m to 19h30m and from 20h30m to 21h00m, only sources brighter than 0.75Jy are listed, and to this level the catalogue is espected to be complete. For detailed discussion of the completeness of the catalogue see the original publication cited above.
1724. The third realization of the ICRF, ICRF3
ID:
ivo://CDS.VizieR/J/A+A/644/A159
Title:
The third realization of the ICRF, ICRF3
Short Name:
J/A+A/644/A159
Date:
21 Oct 2021
Publisher:
CDS
Description:
A new realization of the International Celestial Reference Frame (ICRF) is presented based on the work achieved by a working group of the International Astronomical Union (IAU) mandated for this purpose. This new realization follows the initial realization of theICRF completed in 1997 and its successor, ICRF2, adopted as a replacement in 2009. The new frame, referred to as ICRF3, is based on nearly 40 years of data acquired by very long baseline interferometry at the standard geodetic and astrometric radio frequencies (8.4 and 2.3GHz), supplemented with data collected at higher radio frequencies (24GHz and dual-frequency 32 and 8.4GHz) over the past 15 years. State-of-the-art astronomical and geophysical modeling has been used to analyze these data and derive source positions. The modeling integrates, for the first time, the effect of the galactocentric acceleration of the solar system (directly estimated from the data) which, if not considered, induces significant deformation of the frame due to the data span. The new frame includes positions at 8.4GHz for 4536 extragalactic sources. Of these, 303 sources, uniformly distributed on the sky, are identified as "defining sources" and as such serve to define the axes of the frame. Positions at 8.4GHz are supplemented with positions at 24GHz for 824 sources and at 32GHz for 678 sources. In all, ICRF3 comprises 4588 sources, with three-frequency positions available for 600 of these. Source positions have been determined independently at each of the frequencies in order to preserve the underlying astrophysical content behind such positions. They are reported for epoch 2015.0 and must be propagated for observations at other epochs for the most accurate needs, accounting for the acceleration toward the Galactic center, which results in a dipolar proper motion field of amplitude 0.0058 milliarcsecond/yr (mas/yr). The frame is aligned onto the International Celestial Reference System to within the accuracy of ICRF2 and shows a median positional uncertainty of about 0.1mas in right ascension and 0.2 mas in declination, with a noise floor of 0.03mas in the individual source coordinates. A subset of 500 sources is found to have extremely accurate positions, in the range of 0.03 to 0.06mas, at the traditional 8.4GHz frequency. Comparing ICRF3 with the recently released Gaia Celestial Reference Frame 2 in the optical domain, there is no evidence for deformations larger than 0.03 mas between the two frames, in agreement with the ICRF3 noise level. Significant positional offsets between the three ICRF3 frequencies are detected for about 5% of the sources.Moreover, a notable fraction (22%) of the sources shows optical and radio positions that are significantly offset. There are indications that these positional offsets may be the manifestation of extended source structures. This third realization of the ICRF was adopted by the IAU at its 30th General Assembly in August 2018 and replaced the previous realization, ICRF2, on January 1, 2019.
1725. The Toothbrush relic 14.25GHz image
ID:
ivo://CDS.VizieR/J/A+A/642/L13
Title:
The Toothbrush relic 14.25GHz image
Short Name:
J/A+A/642/L13
Date:
21 Oct 2021
Publisher:
CDS
Description:
Radio relics trace shock fronts generated in the intracluster medium (ICM) during cluster mergers. The particle acceleration mechanism at the shock fronts is not yet completely understood. We observed the Toothbrush relic with the Effelsberg and Sardinia Radio Telescope at 14.25GHz and 18.6GHz, respectively. Unlike previously claimed, the integrated spectrum of the relic closely follows a power law over almost three orders of magnitude in frequency, with a spectral index of {alpha}_58MHz_^18.6GHz^=-1.16+/-0.03. Our finding is consistent with a power-law injection spectrum, as predicted by diffusive shock acceleration theory. The result suggests that there is only little magnetic field strength evolution downstream of the shock. From the lack of spectral steepening, we find that either the Sunyaev-Zeldovich decrement produced by the pressure jump is less extended than ~600kpc along the line of sight or, conversely, that the relic is located far behind in the cluster. For the first time, we detect linearly polarized emission from the "brush" at 18.6GHz. Compared to 8.3GHz, the degree of polarization across the brush increases at 18.6GHz, suggesting a strong Faraday depolarization toward lower frequencies. The observed depolarization is consistent with an intervening magnetized screen that arises from the dense ICM containing turbulent magnetic fields. The depolarization, corresponding to a standard deviation of the rotation measures as high as {sigma}_RM_=212+/-23rad/m^2^, suggests that the brush is located in or behind the ICM. Our findings indicate that the Toothbrush relic can be consistently explained by the standard scenario for relic formation.
1726. The 35um absorption line towards 1612MHz masers
ID:
ivo://CDS.VizieR/J/A+A/434/201
Title:
The 35um absorption line towards 1612MHz masers
Short Name:
J/A+A/434/201
Date:
21 Oct 2021
Publisher:
CDS
Description:
The 1612MHz hydroxyl maser in circumstellar envelopes has long been thought to be pumped by 34.6{mu}m photons. Only recently, the Infrared Space Observatory has made possible spectroscopic observations which enable the direct confirmation of this pumping mechanism in a few cases. To look for the presence of this pumping line, we have searched the Infrared Space Observatory Data Archive and found 178 spectra with data around 34.6{mu}m for 87 galactic 1612MHz masers.
1727. The UTR-2 Very Low-Frequency Sky Survey Data
ID:
ivo://CDS.VizieR/VIII/80
Title:
The UTR-2 Very Low-Frequency Sky Survey Data
Short Name:
VIII/80
Date:
21 Oct 2021
Publisher:
CDS
Description:
The results of the very-low frequency (16.7MHz) survey of discrete sources made with the UTR-2 radio telescope is presented. The survey concerns the declination zones -13{deg} to -2{deg}, 0{deg} to 20{deg}, 30{deg} to 40{deg}, and 41{deg} to 60{deg}. The UTR-2 radio source catalogue contains an estimate of the coordinates and flux densities of 1819 sources measured at a number of the lowest frequencies used in contemporary radio astronomy within the range from 10 to 25 MHz. The catalogue is made of two parts: mean.dat: the averaged values of the coordinates and the corresponding errors, the source flux-density at the middle UTR-2 frequency 16.7 MHz as obtained from measured spectrum of the source at all UTR-2 frequencies and its error, the value of measured low-frequency spectral index with respect to which the estimate of has been obtained, the parameter W characterizing the integral reliability of the obtained source estimates and the corresponding object name from higher-frequency radio survey provided the source has been identified. To indicate the integral readability of the source parameters obtained we used the symbols A, B and C. These reliability estimates take into account the total number of measurements, coordinate scatter, number of frequencies and hour-angle settings at which the source parameters have been evaluated. The highly reliable observation results have been marked with symbol A . The sources whose parameters can be used without an additional analysis are marked with B and sources whose parameters are to be used with care have been marked with C. data.dat: this file contains the experimental estimates of the source coordinates and flux densities as well as their errors at each operating frequency of the UTR-2 in the order of their increasing; the total number (N) of successive observations according to which the estimates were obtained and the number of different hour-angle settings (NRA) of the reception pattern at which the source was observed. In cases when the observations did not allow us to obtain a reliable estimates of a source flux density the catalogue contains only their upper limits which are not accompanied by errors. The approximated values of as well as low-frequency spectral indices are presented only for those sources which have flux density estimates obtained at not less than three different UTR-2 frequencies.
1728. The UTR-2 Very Low-Frequency Sky Survey Data
ID:
ivo://CDS.VizieR/VIII/41
Title:
The UTR-2 Very Low-Frequency Sky Survey Data
Short Name:
VIII/41
Date:
21 Oct 2021
Publisher:
CDS
Description:
The results of the very-low frequency (16.7MHz) survey of discrete sources made with the UTR-2 radio telescope is presented. The survey concerns the declination zones -13{deg} to -2{deg}, 0{deg} to 20{deg}, and 41{deg} to 60{deg}. The UTR-2 radio source catalogue contains an estimate of the coordinates and flux densities of 1819 sources measured at a number of the lowest frequencies used in contemporary radio astronomy within the range from 10 to 25 MHz. The catalogue is made of two parts: mean.dat: the averaged values of the coordinates and the corresponding errors, the source flux-density at the middle UTR-2 frequency 16.7 MHz as obtained from measured spectrum of the source at all UTR-2 frequencies and its error, the value of measured low-frequency spectral index with respect to which the estimate of has been obtained, the parameter W characterizing the integral reliability of the obtained source estimates and the corresponding object name from higher-frequency radio survey provided the source has been identified. To indicate the integral readability of the source parameters obtained we used the symbols A, B and C. These reliability estimates take into account the total number of measurements, coordinate scatter, number of frequencies and hour-angle settings at which the source parameters have been evaluated. The highly reliable observation results have been marked with symbol A . The sources whose parameters can be used without an additional analysis are marked with B and sources whose parameters are to be used with care have been marked with C. data.dat: this file contains the experimental estimates of the source coordinates and flux densities as well as their errors at each operating frequency of the UTR-2 in the order of their increasing; the total number (N) of successive observations according to which the estimates were obtained and the number of different hour-angle settings (NRA) of the reception pattern at which the source was observed. In cases when the observations did not allow us to obtain a reliable estimates of a source flux density the catalogue contains only their upper limits which are not accompanied by errors. The approximated values of as well as low-frequency spectral indices are presented only for those sources which have flux density estimates obtained at not less than three different UTR-2 frequencies.
1729. The VLA-COSMOS survey
ID:
ivo://CDS.VizieR/J/AJ/128/1974
Title:
The VLA-COSMOS survey
Short Name:
J/AJ/128/1974
Date:
21 Oct 2021
Publisher:
CDS
Description:
We present a catalog of 246 radio sources found in the central 1{deg} of the COSMOS field at 1.4GHz. The VLA pilot project data have a resolution of 1.9"x1.6" and an rms noise limit of ~25-100{mu}Jy/beam covering 0.837{deg}^2. About 20 radio sources are clearly extended, and most of them appear to be double-lobed radio galaxies. We find evidence for a cluster of seven radio galaxies with an extent of ~10' southeast of the COSMOS field center.
1730. The VLA-COSMOS survey. IV.
ID:
ivo://CDS.VizieR/J/ApJS/188/384
Title:
The VLA-COSMOS survey. IV.
Short Name:
J/ApJS/188/384
Date:
21 Oct 2021
Publisher:
CDS
Description:
In the context of the VLA-COSMOS Deep project, additional VLA A array observations at 1.4GHz were obtained for the central degree of the COSMOS field and combined with the existing data from the VLA-COSMOS Large project. A newly constructed Deep mosaic with a resolution of 2.5" was used to search for sources down to 4{sigma} with 1{sigma}~12uJy/beam in the central 50'x50'. This new catalog is combined with the catalog from the Large project (obtained at 1.5"x1.4" resolution) to construct a new Joint catalog. All sources listed in the new Joint catalog have peak flux densities of >=5{sigma} at 1.5" and/or 2.5" resolution to account for the fact that a significant fraction of sources at these low flux levels are expected to be slightly resolved at 1.5" resolution. All properties listed in the Joint catalog, such as peak flux density, integrated flux density, and source size, are determined in the 2.5" resolution Deep image. In addition, the Joint catalog contains 43 newly identified multi-component sources.