- ID:
- ivo://CDS.VizieR/J/MNRAS/410/2662
- Title:
- AMI 1.8cm observations in c2d small clouds
- Short Name:
- J/MNRAS/410/2662
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We perform deep 1.8-cm radio continuum imaging towards 13 protostellar regions selected from the Spitzer c2d small clouds and cores programme at high resolution (25-arcsec) in order to detect and quantify the cm-wave emission from deeply embedded young protostars. Within these regions we detect 15 compact radio sources which we identify as radio protostars including two probable new detections. The sample is in general of low bolometric luminosity and contains several of the newly detected VeLLO sources. We determine the 1.8cm radio luminosity to bolometric luminosity correlation, L_rad_-L_bol_, for the sample and discuss the nature of the radio emission in terms of the available sources of ionized gas. We also investigate the Lrad-LIR correlation and suggest that radio flux density may be used as a proxy for the internal luminosity of low-luminosity protostars.
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Search Results
- ID:
- ivo://CDS.VizieR/J/MNRAS/429/3330
- Title:
- AMI Galactic Plane Survey at 16GHz. I.
- Short Name:
- J/MNRAS/429/3330
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The AMI Galactic Plane survey is being made with the Arcminute Microkelvin Imager (AMI) Small Array at 15.7GHz and with resolution of approximately 3arcmin. This is the first data release, covering ~868deg^2^ of the Northern Galactic plane between |b|~+/-5{deg} and above {delta}=40{deg} with a noise level of ~3mJy/beam away from bright sources. The source catalogue contains a total of 3503 sources.
- ID:
- ivo://CDS.VizieR/J/MNRAS/453/1396
- Title:
- AMI Galactic Plane Survey at 16GHz. II.
- Short Name:
- J/MNRAS/453/1396
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The Arcminute Microkelvin Imager Galactic Plane Survey (AMIGPS) provides mJy-sensitivity, arcminute-resolution interferometric images of the northern Galactic plane at ~16GHz. The first data release covered 76{deg}<=l<=170{deg} between latitudes of |b|<=5{deg}; here we present a second data release, extending the coverage to 53{deg}<=l<=193{deg} and including high-latitude extensions to cover the Taurus and California giant molecular cloud regions, and the recently discovered large supernova remnant G159.6+7.3. The total coverage is now 1777{deg}^2^ and the catalogue contains 6509 sources. We also describe the improvements to the data processing pipeline which improves the positional and flux density accuracies of the survey.
- ID:
- ivo://CDS.VizieR/J/MNRAS/473/1512
- Title:
- AMI 15.7GHz GRB catalogue
- Short Name:
- J/MNRAS/473/1512
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present the Arcminute Microkelvin Imager (AMI) Large Array catalogue of 139 gamma-ray bursts (GRBs). AMI observes at a central frequency of 15.7GHz and is equipped with a fully automated rapid-response mode, which enables the telescope to respond to high-energy transients detected by Swift. On receiving a transient alert, AMI can be on-target within 2-min, scheduling later start times if the source is below the horizon. Further AMI observations are manually scheduled for several days following the trigger. The AMI GRB programme probes the early-time (<1d) radio properties of GRBs, and has obtained some of the earliest radio detections (GRB 130427A at 0.36 and GRB 130907A at 0.51d post-burst). As all Swift GRBs visible to AMI are observed, this catalogue provides the first representative sample of GRB radio properties, unbiased by multiwavelength selection criteria. We report the detection of six GRB radio afterglows that were not previously detected by other radio telescopes, increasing the rate of radio detections by 50 per cent over an 18-month period. The AMI catalogue implies a Swift GRB radio detection rate of >~15 per cent, down to ~0.2mJy/beam. However, scaling this by the fraction of GRBs AMI would have detected in the Chandra & Frail (2012, Cat. J/ApJ/746/156) sample (all radio-observed GRBs between 1997 and 2011), it is possible ~44-56 per cent of Swift GRBs are radio bright, down to ~0.1-0.15mJy/beam. This increase from the Chandra & Frail (2012, Cat. J/ApJ/746/156) rate (~30 per cent) is likely due to the AMI rapid-response mode, which allows observations to begin while the reverse-shock is contributing to the radio afterglow.
- ID:
- ivo://CDS.VizieR/J/MNRAS/415/893
- Title:
- AMI-LA 16 GHz sources in Perseus region
- Short Name:
- J/MNRAS/415/893
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present deep radio continuum observations of the cores identified as deeply embedded young stellar objects in the Perseus molecular cloud by the Spitzer c2d programme at a wavelength of 1.8cm with the Arcminute Microkelvin Imager Large Array (AMI-LA). We detect 72% of Class 0 objects from this sample and 31% of Class I objects. No starless cores are detected. We use the flux densities measured from these data to improve constraints on the correlations between radio luminosity and bolometric luminosity, infrared luminosity and, where measured, outflow force. We discuss the differing behaviour of these objects as a function of protostellar class and investigate the differences in radio emission as a function of core mass. Two of four possible very low luminosity objects (VeLLOs) are detected at 1.8cm.
- 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/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/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.