- ID:
- ivo://CDS.VizieR/J/A+A/308/573
- Title:
- Ammonia on YSOs IRAS sources
- Short Name:
- J/A+A/308/573
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present observations of NH_3_ (1,1) and (2,2) lines in two flux-limited samples of IRAS sources selected according to colour criteria which should result in a high fraction of Young Stellar Objects. The first sample contains sources (named 'LOW') whose evolutionary status is essentially unknown, while the second sample contains sources (named 'HIGH') possibly associated with ultracompact HII regions, the distinction being based on the IRAS [25-12] colour.
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- ID:
- ivo://CDS.VizieR/J/ApJS/175/509
- Title:
- Ammonia spectral atlas in Perseus
- Short Name:
- J/ApJS/175/509
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present ammonia observations of 193 dense cores and core candidates in the Perseus molecular cloud made using the Robert F. Byrd Green Bank Telescope. We simultaneously observed the NH_3_(1,1), NH_3_(2,2), C_2_S (2_1_=>1_0_), and C^34^_2_S(2_1_=>1_0_) transitions near {nu}=23GHz for each of the targets with a spectral resolution of {delta}v~0.024km/s. We find ammonia emission associated with nearly all of the (sub)millimeter sources, as well as at several positions with no associated continuum emission. For each detection, we have measured physical properties by fitting a simple model to every spectral line simultaneously. Where appropriate, we have refined the model by accounting for low optical depths, multiple components along the line of sight, and imperfect coupling to the GBT beam. For the cores in Perseus, we find a typical kinetic temperature of T_k_=11K, a typical column density of N_NH3_~10^14.5^/cm2, and velocity dispersions ranging from {sigma}v=0.07 to 0.7km/s. However, many cores with {sigma}v>0.2km/s show evidence for multiple velocity components along the line of sight.
- ID:
- ivo://CDS.VizieR/J/ApJS/189/1
- Title:
- A 3.5mm polarimetric survey of radio-loud AGNs
- Short Name:
- J/ApJS/189/1
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present the results from the first large (>100 sources) 3.5mm polarimetric survey of radio-loud active galactic nuclei (AGNs). This wavelength is favorable within the radio-millimeter range for measuring the intrinsic linearly polarized emission from AGNs, since in general it is only marginally affected by Faraday rotation of the electric vector position angle and depolarization. The I, Q, U, and V Stokes parameter observations were performed with the XPOL polarimeter at the IRAM 30m Telescope on different observing epochs from 2005 July (when most of the measurements were made) to 2009 October. Our sample consists of 145 flat-radio-spectrum AGNs with declination >-30{deg} (J2000.0) and flux density >~1Jy at ~86GHz, as measured at the IRAM 30m Telescope from 1978 to 1994. This constraint on the radio spectrum causes our sample to be dominated by blazars, which allows us to conduct new statistical studies on this class of high-luminosity, relativistically beamed emitters. Over our entire source sample, the luminosity of the jets is anticorrelated with the degree of linear polarization. Consistent with previous findings claiming larger Doppler factors for brighter {gamma}-ray blazars, quasars listed in our sample, and in the Fermi Large Area Telescope Bright Source Catalog (LBAS, Abdo et al., 2009ApJ...700..597A), show larger luminosities than non-LBAS ones, but our data do not allow us to confirm the same for BL Lac objects. Our new data can be used to estimate the 3.5mm AGN contribution to measurements of the linear polarization of the cosmic microwave background, such as those performed by the Planck satellite.
- ID:
- ivo://CDS.VizieR/VIII/86
- Title:
- Analysis of the RC catalog sample.
- Short Name:
- VIII/86
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- of paper I: 432 radio sources of the RC catalog produced in 1980-1985 at RATAN-600 radio telescope based on a deep survey of a sky strip centered on the declination of the SS433 source are identified in the region overlapping with FIRST and SDSS surveys (about 132{deg}^2^ large). The NVSS catalog was used as the reference catalog for refining the coordinates of the radio sources. The morphology is found for about 75% of the objects of the sample and the ratio of single, double and multicomponent radio sources is computed based on FIRST radio maps. The 74, 365, 1400, and 4850MHz data of the VLSS, TXS, NVSS, FIRST, and GB6 catalogs are used to analyze the shape of the spectra.
- ID:
- ivo://CDS.VizieR/V/67
- Title:
- An astrometric catalogue of radio stars
- Short Name:
- V/67
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Astrometric data in the optical and radio spectral ranges have been assembled for some 200 radio stars which are considered promising objects for linkage of optical and radio frames. Astrophysical data have been added to support observational programmes and data analysis. The full catalogue, in its original form as the file "catalog.ori", contains explanations, followed by the data for each star organised as paragraphs (blocks of lines separated by a blank line). Each paragraph representing a radio star in this catalog consists of 17 categories of stellar parameters; each category may contain zero, one, or more records. The positions, proper motions and parallaxes in the optical and radio domains are assigned categories 1 to 7; categories 8 to 13 deal with photometrical and spectroscopical parameters, duplicity and variability descriptions; and categories 14 to 17 contain references to finding charts and radio maps, as well as remarks about observation priorities. A detailed description of these categories are present at the beginning of the "catalog.ori" file.
- ID:
- ivo://CDS.VizieR/J/A+A/342/378
- Title:
- 6 and 20cm flux densities of radio galaxies
- Short Name:
- J/A+A/342/378
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We discuss the "angular size-redshift" relation for compact radio sources distributed over a wide range of redshifts 0.011<=z<=4.72. Our study is based on a sample of 330 5 GHz VLBI contour maps taken from the literature. Unlike extended source samples, the "angular size - redshift" relation for compact radio sources appears consistent with the predictions of standard Friedmann world models with q_0_=~0.5 without the need to consider evolutionary or selection effects due to a "linear size-luminosity" dependence. By confining our analysis to sources having a spectral index, -0.38<={alpha}<=0.18, and a total radio luminosity, Lh^2^>= 10^26^W/Hz (H_0_=100hkm/s/Mpc, q_0_=0.5 used as a numerical example), we are able to restrict the dispersion in the "angular size-redshift" relation. The best fitting regression analysis in the framework of the Friedmann-Robertson-Walker model gives the value of the deceleration parameter q_0_=0.21+/-0.30 if there are no evolutionary or selection effects due to a "linear size-luminosity", "linear size-redshift" or "linear size-spectral index" dependence.
- ID:
- ivo://CDS.VizieR/J/ApJS/241/37
- Title:
- 1.4 and 5GHz deep JVLA radio survey of M33
- Short Name:
- J/ApJS/241/37
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We have performed new 1.4 and 5 GHz observations of the Local Group galaxy M33 with the Jansky Very Large Array. Our survey has a limiting sensitivity of 20{mu}Jy (4{sigma}) and a resolution of 5.9" (FWHM), corresponding to a spatial resolution of 24pc at 817kpc. Using a new multiresolution algorithm, we have created a catalog of 2875 sources, including 675 with well-determined spectral indices. We detect sources at the position of 319 of the X-ray sources in the Tullmann+ (2011, J/ApJS/193/31) Chandra survey of M33, the majority of which are likely to be background galaxies. The radio source coincident with M33 X-8, the nuclear source, appears to be extended. Along with numerous HII regions or portions of HII region complexes, we detect 155 of the 217 optical supernova remnants (SNRs) included in the lists of Long+, 2010, J/ApJS/187/495 and Lee & Lee, 2014, J/ApJ/793/134, making this by far the largest sample of remnants at known distances with multiwavelength coverage. The remnants show a large dispersion in the ratio of radio to X-ray luminosity at a given diameter, a result that challenges the current generation of models for synchrotron radiation evolution in SNRs.
- ID:
- ivo://CDS.VizieR/J/AJ/119/2801
- Title:
- 8.35 and 14.35GHz flux at Galactic plane
- Short Name:
- J/AJ/119/2801
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present the first images of the Galactic plane (GP; |b|<5{deg}, -15{deg}<l<255{deg}) at 8.35 and 14.35 GHz. These observations used the National Radio Astronomy Observatory-NASA Green Bank Earth Station to survey the sky simultaneously at these frequencies. These are the first results from the GP survey observations, a program to monitor the sky at 8.35 and 14.35 GHz. The GP survey series is intended to detect short-lived radio sources. We present four independent observations of the Galactic plane, combined to provide a set of reference images of the Galactic plane. The first survey, GPA, covers 0.82 sr (6.5%) of the sky. A source list is presented for all sources brighter than 0.9 Jy at 8.35 GHz and also for all sources brighter than 2.5 Jy at 14.35 GHz. The FITS format images, residual images, source lists, and archive data are available over the Internet. Later papers will present the results of the variable source search.
- ID:
- ivo://CDS.VizieR/J/A+A/630/A83
- Title:
- 4.85 and 10.45GHz fluxes of SDSS-FIRST sources
- Short Name:
- J/A+A/630/A83
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- A detailed understanding of how the activity of a galactic nucleus regulates the growth of its host is still missing. To understand the activity and the types of accretion of supermassive black holes in different hosts, it is essential to study radio-optical properties of a large sample of extragalactic sources. In particular, we aim at studying the radio spectral index trends across the optical emission line diagnostic diagrams to search for potential (anti)correlations. To this goal, we combine flux densities from the radio FIRST survey at 1.4GHz (with the flux density range 10mJy<=F1.4<=1000mJy for 209 SDSS sources at intermediate redshift (0.04<=z<=0.4) with the Effelsberg radiotelescope measurements at 4.85GHz and 10.45GHz. The information about the optical emission-line ratios is obtained from the SDSS-DR7 catalogue. Using the Effelsberg data, we were able to infer the two-point radio spectral index distributions for star-forming galaxies, composite galaxies (with a combined contribution to the line emission from the star-formation and AGN activity), Seyferts, and low ionization narrow emission region (LINER) galaxies. While studying the distribution of steep, flat, and inverted sources across optical diagnostic diagrams, we found three distinct classes of radio emitters for our sample: (i) sources with steep radio index, high ionization ratio and high radio loudness, (ii) sources with flat radio index, lower ionization ratio and intermediate radio loudness, (iii) sources with inverted radio index, low ionization ratio and low radio loudness. The classes (i), (ii), (iii) cluster mainly along the transition from Seyfert to LINER sources in the BPT diagram. We interpret these groups as a result of the recurrent nuclear-jet activity.
- ID:
- ivo://CDS.VizieR/J/ApJS/248/18
- Title:
- 44 and 95GHz observations of class I methanol masers
- Short Name:
- J/ApJS/248/18
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We report a simultaneous 44 and 95GHz class I methanol maser survey toward 144 sources from the 95GHz class I methanol maser catalog. The observations were made with the three telescopes of the Korean very long baseline interferometry network operating in single-dish mode. The detection rates are 89% at 44GHz and 77% at 95GHz. There are 106 new discoveries at 44GHz. Comparing the previous 95GHz detections with new observations of the same transitions made using the Purple Mountain Observatory 13.7m radio telescope shows no clear evidence of variability on a timescale of six years. Emission from the 44 and 95GHz transitions shows strong correlations in peak velocity, peak flux density, and integrated flux density, indicating that they are likely cospatial. We found that the peak flux density ratio S_pk,95_/S_pk,44_ decreases as the 44GHz peak flux density increases. We found that some class I methanol masers in our sample might be associated with infrared dark clouds, while others are associated with HII regions, indicating that some sources occur at an early stage of high-mass star formation, while others are located toward more evolved sources.