- ID:
- ivo://CDS.VizieR/J/AJ/113/2000
- Title:
- New quasar radio detections
- Short Name:
- J/AJ/113/2000
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Using the NVSS radio catalog, we have searched for radio emission from 4079 quasars taken from the 1996 version of the Veron-Cetty & Veron [ESO Scientific Report No.X (1996, Cat. <VII/188>)] quasar catalog. The comparison resulted in the positive detection of radio emission from 799 quasars of these, 168 are new radio detections. Examination of the radio luminosities shows a dramatic increase in 9 the fraction of radio-loud quasars from the current epoch to z=0.5 and a gradual decline beyond z=1.0. Inspection of the radio-loud fraction as a function of MB shows little dependence fainter than M_B_=-29.5.
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Search Results
- ID:
- ivo://CDS.VizieR/I/218
- Title:
- New Reference Frame defined by Extragalactic Radio Source
- Short Name:
- I/218
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- This is the annex to Resolution B5 of the XXII Assembly of the IAU. This list of extragalactic objects identifies sources which define the new conventional celestial reference frame together with candidate sources which may, at some future date, be added or replace the defining sources. The text of the resolution has been quoted below. The list is available as the original latex file or as an ascii file.
- ID:
- ivo://CDS.VizieR/J/ApJS/253/48
- Title:
- New rotation measures from the CGPS
- Short Name:
- J/ApJS/253/48
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Faraday rotation provides a valuable tracer of magnetic fields in the interstellar medium; catalogs of Faraday rotation measures provide key observations for studies of the Galactic magnetic field. We present a new catalog of rotation measures derived from the Canadian Galactic Plane Survey, covering a large region of the Galactic plane spanning 52{deg}<l<192{deg}, -3{deg}<b<5{deg}, along with northern and southern latitude extensions around l~105{deg}. We have derived rotation measures for 2234 sources (4 of which are known pulsars), 75% of which have no previous measurements, over an area of approximately 1300deg^2^. These new rotation measures increase the measurement density for this region of the Galactic plane by a factor of 2.
- ID:
- ivo://CDS.VizieR/J/ApJ/670/92
- Title:
- New sample of low-mass black holes in AGN
- Short Name:
- J/ApJ/670/92
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present an expanded sample of low-mass black holes (BHs) found in galactic nuclei. Using standard virial mass techniques to estimate BH masses, we select from the Fourth Data Release of the Sloan Digital Sky Survey all broad-line active galaxies with masses <2x10^6^M_{sun}_ BHs in this mass regime provide unique tests of the relationship between BHs and galaxies, since their late-type galaxy hosts do not necessarily contain classical bulges. Furthermore, they provide observational analogs of primordial seed BHs and are expected, when merging, to provide strong gravitational signals for future detectors such as LISA. From our preliminary sample of 19, we have increased the total sample by an order of magnitude to 174, as well as an additional 55 (less secure) candidates.
- ID:
- ivo://CDS.VizieR/J/MNRAS/391/369
- Title:
- New z>=3.6 QSOs from FIRST-SDSS DR5
- Short Name:
- J/MNRAS/391/369
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We aim to obtain a complete sample of redshift z>=3.6 radio quasi-stellar objects (QSOs) from the Faint Images of the Radio Sky at Twenty cm survey (FIRST) sources (S_1.4GHz_>1mJy) having star-like counterparts in the Sloan Digital Sky Survey (SDSS) Data Release 5 (DR5) photometric survey (r_AB_<=20.2). Our starting sample of 8665 FIRST-DR5 pairs includes 4250 objects with spectra in DR5, 52 of these being z>=3.6 QSOs. We found that simple supervised neural networks, trained on the sources with DR5 spectra, and using optical photometry and radio data, are very effective for identifying high-z QSOs in a sample without spectra. For the sources with DR5 spectra the technique yields a completeness (fraction of actual high-z QSOs classified as such by the neural network) of 96 per cent, and an efficiency (fraction of objects selected by the neural network as high-z QSOs that actually are high-z QSOs) of 62 per cent. Applying the trained networks to the 4415 sources without DR5 spectra we found 58 z>=3.6 QSO candidates. We obtained spectra of 27 of them, and 17 are confirmed as high-z QSOs. Spectra of 13 additional candidates from the literature and from SDSS Data Release 6 (DR6) revealed seven more z>=3.6 QSOs, giving an overall efficiency of 60 per cent (24/40).
- ID:
- ivo://CDS.VizieR/J/A+A/622/A8
- Title:
- NGC 3184, 4736, 5055 and 5194 LOFAR & WSRT maps
- Short Name:
- J/A+A/622/A8
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Radio continuum (RC) emission in galaxies allows us to measure star formation rates (SFRs) unaffected by extinction due to dust, of which the low-frequency part is uncontaminated from thermal (free-free) emission. We calibrate the conversion from the spatially resolved 140MHz RC emission to the SFR surface density (SFR) at 1kpc scale. Radio spectral indices give us, by means of spectral ageing, a handle on the transport of cosmic rays using the electrons as a proxy for GeV nuclei. We used recent observations of three galaxies (NGC 3184, 4736, and 5055) from the LOFAR Two-metre Sky Survey (LoTSS), and archival LOw Frequency ARay (LOFAR) data of NGC 5194. Maps were created with the facet calibration technique and converted to radio {Sigma}SFR maps using the Condon relation. We compared these maps with hybrid {Sigma}SFR maps from a combination of GALEX far-ultraviolet and Spitzer 24um data using plots tracing the relation at the highest angular resolution allowed by our data at 1.2x1.2-kpc^2^ resolution.
- ID:
- ivo://CDS.VizieR/J/AJ/140/1093
- Title:
- NGC7332/7339 and NGC 1156 HI sources from AGES
- Short Name:
- J/AJ/140/1093
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Two 5deg^2^ regions around the NGC 7332/9 galaxy pair and the isolated galaxy NGC 1156 have been mapped in the 21cm line of neutral hydrogen (HI) with the Arecibo L-band Feed Array out to a redshift of ~0.065 (~20000km/s) as part of the Arecibo Galaxy Environment Survey. One of the aims of this survey is to investigate the environment of galaxies by identifying dwarf companions and interaction remnants; both of these areas provide the potential for such discoveries. The neutral hydrogen observations were complemented by optical and radio follow-up observations with a number of telescopes. A total of 87 galaxies were found, of which 39 (45%) were previously catalogued and 15 (17%) have prior redshifts. Two dwarf galaxies have been discovered in the NGC 7332 group and a single dwarf galaxy in the vicinity of NGC 1156. A parallel optical search of the area revealed one further possible dwarf galaxy near NGC 7332.
- ID:
- ivo://CDS.VizieR/J/A+A/641/A151
- Title:
- NGC 7213 central region molecular gas
- Short Name:
- J/A+A/641/A151
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present a multi-wavelength study (from X-ray to mm) of the nearby low-luminosity active galactic nucleus (LLAGN) NGC 7213. We combine the information from the different bands to characterise the source in terms of contribution from the AGN and the host-galaxy interstellar medium (ISM). This approach allows us to provide a coherent picture of the role of the AGN and its impact, if any, on the star formation and molecular gas properties of the host galaxy. We focused our study on archival ALMA Cycle 1 observations, where the CO(2-1) emission line has been used as a tracer of the molecular gas. Using the 3DBarolo code on ALMA data, we performed the modelling of the molecular gas kinematics traced by the CO(2-1) emission, finding a rotationally dominated pattern. The molecular gas mass of the host galaxy was estimated from the integrated CO(2-1) emission line obtained with APEX data, assuming an alpha_co conversion factor. Had we used the ALMA data, we would have underestimated the gas masses by a factor ~3, given the filtering out of the large-scale emission in interferometric observations. We also performed a complete X-ray spectral analysis on archival observations, revealing a relatively faint and unobscured AGN. The AGN proved to be too faint to significantly affect the properties of the host galaxy, such as star formation activity and molecular gas kinematics and distribution.
- ID:
- ivo://CDS.VizieR/J/MNRAS/379/275
- Title:
- NGC 5033 1.4GHz radio emission
- Short Name:
- J/MNRAS/379/275
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present new continuum VLA observations of the nearby Sy 1.5 galaxy NGC 5033, made at 4.9- and 8.4-GHz on 2003 April 8. Combined with VLA archival observations at 1.4- and 4.9-GHz made on 1993 August 7, 1999 August 29 and 1999 October 31, we sample the galaxy radio emission at scales ranging from the nuclear regions (<100pc) to the outer regions of the disc (~40kpc). The high-resolution VLA images show a corejet structure for the Sy 1.5 nucleus.
- ID:
- ivo://CDS.VizieR/J/A+A/586/A98
- Title:
- NGC 2683 VLA C and D datacubes
- Short Name:
- J/A+A/586/A98
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- New deep VLA D array HI observations of the highly inclined nearby spiral galaxy NGC 2683 are presented. Archival C array data were processed and added to the new observations. To investigate the 3D structure of the atomic gas disk, we made different 3D models for which we produced model HI data cubes. The main ingredients of our best-fit model are (i) a thin disk inclined by 80{deg}; (ii) a crude approximation of a spiral and/or bar structure by an elliptical surface density distribution of the gas disk; (iii) a slight warp in inclination between 10kpc<=R<=20kpc (decreasing by 10{deg}); (iv) an exponential flare that rises from 0.5kpc at R=9kpc to 4kpc at R=15kpc, stays constant until R=22kpc, and decreases its height for R>22kpc; and (v) a low surface-density gas ring with a vertical offset of 1.3kpc. The slope of NGC 2683's flare is comparable, but somewhat steeper than those of other spiral galaxies. NGC 2683's maximum height of the flare is also comparable to those of other galaxies. On the other hand, a saturation of the flare is only observed in NGC 2683. Based on the comparison between the high resolution model and observations, we exclude the existence of an extended atomic gas halo around the optical and thin gas disk. Under the assumption of vertical hydrostatic equilibrium we derive the vertical velocity dispersion of the gas. The high turbulent velocity dispersion in the flare can be explained by energy injection by (i) supernovae; (ii) magneto-rotational instabilities; (iii) interstellar medium stirring by dark matter substructure; or (iv) external gas accretion. The existence of the complex large-scale warping and asymmetries favors external gas accretion as one of the major energy sources that drives turbulence in the outer gas disk. We propose a scenario where this external accretion leads to turbulent adiabatic compression that enhances the turbulent velocity dispersion and might quench star formation in the outer gas disk of NGC 2683.
