- ID:
- ivo://CDS.VizieR/J/MNRAS/405/2062
- Title:
- AGN candidates from 2MASS/ROSAT catalogs
- Short Name:
- J/MNRAS/405/2062
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We report on the near-infrared-selected active galactic nuclei (AGN) candidates extracted from Two Micron All Sky Survey (2MASS)/ROSAT catalogues and discuss their properties. First, near-infrared counterparts of an X-ray source in ROSAT catalogues [namely bright source catalogue (BSC, Cat. IX/10) and faint source catalogue (FSC, Cat. IX/29)] were extracted by positional cross-identification of <=30arcsec. As these counterparts would contain many mis-identifications, we further imposed near-infrared colour selection criteria and extracted reliable AGN candidates (BSC: 5273, FSC: 10071). Of the 5273 (10071) candidates in the BSC (FSC), 2053 (1008) are known AGNs. Near-infrared and X-ray properties of candidates show similar properties with known AGNs and are consistent with the previous studies. We also searched for counterparts in other wavelengths (i.e. optical, near-infrared and radio) and investigated properties in multiwavelength. No significant difference between known AGNs and unclassified sources could be seen. However, some unclassified sources in the FSC showed slightly different properties compared with known AGNs. Consequently, it is highly probable that we could extract reliable AGN candidates, though candidates in the FSC might be spurious.
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- ID:
- ivo://CDS.VizieR/J/A+A/535/A69
- Title:
- AGN Fermi/LAT {gamma}-ray and 37GHz fluxes
- Short Name:
- J/A+A/535/A69
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Although the Fermi mission has increased our knowledge of {gamma}-ray AGN, many questions remain, such as the site of {gamma}-ray production, the emission mechanism, and the factors that govern the strength of the emission. Using data from a high radio band, 37GHz, uncontaminated by other radiation components besides the jet emission, we study these questions with averaged flux densities over the the first year of Fermi operations. We look for possible correlations between the 100MeV-100GeV band used by the Fermi satellite and 37GHz radio band observed at the Aalto University Metsahovi Radio Telescope, as well as for differences between the {gamma}-ray emission of different AGN subsamples. We use data averaged over the 1FGL period. Our sample includes 249 northern AGN, including a complete sample of 68 northern AGN with a measured average flux density exceeding 1Jy.
- ID:
- ivo://CDS.VizieR/J/AJ/130/1418
- Title:
- AGN jet kinematics
- Short Name:
- J/AJ/130/1418
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present total and polarized intensity images of 15 active galactic nuclei obtained with the Very Long Baseline Array at 7mm (43GHz) wavelength at 17 epochs from 1998 March to 2001 April. At some epochs the images are accompanied by nearly simultaneous polarization measurements at 3mm (86GHz) with the Berkeley-Illinois-Maryland Association (BIMA) array (Hat Creek, California), 1.35/0.85mm (230/350GHz) with the James Clerk Maxwell Telescope (JCMT; using SCUBA and its polarimeter, and at the Steward Observatory 1.5m telescope (Mount Lemmon, Arizona) with the Two-Holer Polarimeter/Photometer over an effective wavelength range of ~6000-7000{AA}. Here we analyze the 7mm images to define the properties of the jets of two radio galaxies, five BL Lac objects, and eight quasars on angular scales >~0.1mas. We determine the apparent velocities of 106 features in the jets.
- ID:
- ivo://CDS.VizieR/J/ApJS/171/61
- Title:
- All-Sky Survey of Flat-Spectrum Radio Sources
- Short Name:
- J/ApJS/171/61
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We have assembled an 8.4GHz survey of bright, flat-spectrum ({alpha}>-0.5) radio sources with nearly uniform extragalactic (|b|>10{deg}) coverage for sources brighter than S_4.8GHz_=65mJy. The catalog is assembled from existing observations (especially CLASS and the Wright et al., Cat VIII/38, PMN-CA survey), augmented by reprocessing of archival VLA and ATCA data and by new observations to fill in coverage gaps. We refer to this program as CRATES, the Combined Radio All-Sky Targeted Eight GHz Survey. The resulting catalog provides precise positions, subarcsecond structures, and spectral indices for some 11000 sources. We describe the morphology and spectral index distribution of the sample and comment on the survey's power to select several classes of interesting sources, especially high-energy blazars. Comparison of CRATES with other high-frequency surveys also provides unique opportunities for identification of high-power radio sources.
- ID:
- ivo://CDS.VizieR/J/A+A/630/A59
- Title:
- ALMA continuum-subtracted datacubes for 48 QSOs
- Short Name:
- J/A+A/630/A59
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present the stacking analysis of a sample of 48 quasi-stellar objects (QSOs) at 4.5<z<7.1 detected by the Atacama Large Millimetre Array (ALMA) in the [CII] {lambda}158um emission line to investigate the presence and the properties of massive, cold outflows associated with broad wings in the [CII] profile. The high sensitivity reached through this analysis allows us to reveal very broad [CII] wings tracing the presence of outflows with velocities in excess of 1000km/s. We find that the luminosity of the broad [CII] emission increases with LAGN, while it does not significantly depend on the star formation rate of the host galaxy, indicating that the central active galactic nucleus (AGN) is the main driving mechanism of the [CII] outflows in these powerful, distant QSOs. From the stack of the ALMA cubes, we derive an average outflow spatial extent of ~3.5kpc. The average atomic neutral mass outflow rate inferred from the stack of the whole sample is dM_out_/dt~100M_{sun}_/yr, while for the most luminous systems it increases to ~200M_{sun}_/yr. The associated outflow kinetic power is about 0.1% of L_AGN_, while the outflow momentum rate is ~L_AGN_/c or lower, suggesting that these outflows are either driven by radiation pressure onto dusty clouds or, alternatively, are driven by the nuclear wind and energy conserving but with low coupling with the interstellar medium. We discuss the implications of the resulting feedback effect on galaxy evolution in the early Universe.
- ID:
- ivo://CDS.VizieR/J/A+A/641/L2
- Title:
- ALMA third image of lensed quasar PKS 1830-211
- Short Name:
- J/A+A/641/L2
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Strong gravitational lensing distorts our view of sources at cosmological distances but brings invaluable constraints on the mass content of foreground objects and on the geometry and properties of the Universe. We report the detection of a third continuum source toward the strongly lensed quasar PKS 1830-211 in ALMA multi-frequency observations of high dynamic range and high angular resolution. This third source is point-like and located slightly to the north of the diagonal joining the two main lensed images, A and B, 0.3" away from image B. It has a flux density that is 140 times weaker than images A and B and a similar spectral index, compatible with synchrotron emission. We conclude that this source is most likely the expected highly de-magnified third lensed image of the quasar. In addition, we detect, for the first time at millimeter wavelengths, weak and asymmetrical extensions departing from images A and B that correspond to the brightest regions of the Einstein ring seen at centimeter wavelengths. Their spectral index is steeper than that of compact images A, B, and C, which suggests that they arise from a different component of the quasar. Using the GravLens code, we explore the implications of our findings on the lensing model and propose a simple model that accurately reproduces our ALMA data and previous VLA observations. With a more precise and accurate measurement of the time delay between images A and B, the system PKS 1830-211 could help to constrain the Hubble constant to a precision of a few percent.
- 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/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/476/L17
- Title:
- 86 and 43GHz observations of NRAO 150
- Short Name:
- J/A+A/476/L17
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- NRAO 150, a compact and bright radio to mm source showing core/jet structure, has been recently identified as a quasar at redshift z=1.52 through a near-IR spectral observation. The aim is to study the jet kinematics on the smallest accessible scales and to compute the first estimates of its basic physical properties. We have analysed the ultra-high-resolution images from a new monitoring program at 86GHz and 43GHz with the Global mm VLBI Array and the VLBA, respectively. An additional archival calibration VLBA data set, covering the period from 1997 to 2007, has been used. Our data show an extreme projected counter-clockwise jet position angle swing at an angular rate of up to ~11{deg}/yr within the inner ~3pc of the jet, which is associated with a non-ballistic superluminal motion of the jet within this region.
- ID:
- ivo://CDS.VizieR/J/MNRAS/434/956
- Title:
- AT20G high-angular-resolution catalogue
- Short Name:
- J/MNRAS/434/956
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present the high-angular-resolution catalogue for the Australia Telescope 20GHz (AT20G, Cat. J/MNRAS/402/2403) survey, using the high-angular-resolution 6-km antenna data at the baselines of ~4500m of the Australia Telescope Compact Array. We have used the data to produce the visibility catalogue that separates the compact active galactic nuclei (AGNs) from the extended radio sources at the 0.15arcsec angular scale, corresponding to the linear size scale of 1kpc at redshifts higher than 0.7. We find the radio population at 20GHz to be dominated by compact AGNs constituting 77% of the total sources in the AT20G. We introduce the visibility-spectra diagnostic plot, produced using the AT20G cross-matches with lower frequency radio surveys at 1GHz [the NRAO VLA Sky Survey (NVSS, Cat. VIII/65) and the Sydney University Molonglo Sky Survey (SUMSS, Cat. VIII/81)], that separates the 20GHz population into distinct sub-populations of the compact AGNs, the compact steep-spectrum (CSS) sources, the extended AGN-powered sources and extended flat-spectrum sources. The extended flat-spectrum sources include a local thermal emitting population of high-latitude planetary nebulae and also gravitational lens and binary black hole candidates among the AGNs. We find a smooth transition in properties between the CSS sources and the AGN populations. The visibility catalogue, together with the main AT20G survey, provides an estimate of angular size scales for sources in the AT20G and an estimate of the flux arising from central cores of extended radio sources. The identification of the compact AGNs in the AT20G survey provides high-quality calibrators for high-frequency radio telescope arrays and very large baseline interferometry observations.
