- ID:
- ivo://CDS.VizieR/J/ApJ/765/62
- Title:
- SDSS-DR7 optical spectra analysis of radio galaxies
- Short Name:
- J/ApJ/765/62
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We study a large sample of narrow-line radio galaxies (NLRGs) with extended radio structures. Using 1.4GHz radio luminosities L_1.4_, narrow optical emission line luminosities L_[OIII]_ and L_Halpha_, as well as black hole masses M_BH_ derived from stellar velocity dispersions measured from the optical spectra obtained with the Sloan Digital Sky Survey, we find that (1) NLRGs cover about four decades of the Eddington ratio, {lambda}{equiv}L_bol_/L_Edd_{prop.to}L_line_/M_BH_; (2) L_1.4_/M_BH_ strongly correlates with {lambda}; and (3) radio loudness, R=L_1.4_/L_Line_, strongly anti-correlates with {lambda}. A very broad range of the Eddington ratio indicates that the parent population of NLRGs includes both radio-loud quasars (RLQs) and broad-line radio galaxies (BLRGs). The correlations they obey and their high jet production efficiencies favor a jet production model which involves the so-called magnetically choked accretion scenario. In this model, production of the jet is dominated by the Blandford-Znajek mechanism, and the magnetic fields in the vicinity of the central black hole are confined by the ram pressure of the accretion flow. Since large net magnetic flux accumulated in central regions of the accretion flow required by the model can take place only via geometrically thick accretion, we speculate that the massive, "cold" accretion events associated with luminous emission-line active galactic nucleus can be accompanied by an efficient jet production only if preceded by a hot, very sub-Eddington accretion phase.
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Search Results
- ID:
- ivo://CDS.VizieR/J/ApJ/888/36
- Title:
- SDSS/FIRST dwarf galaxies with VLA high res. obs.
- Short Name:
- J/ApJ/888/36
- Date:
- 25 Oct 2021 10:17:58
- Publisher:
- CDS
- Description:
- We present a sample of nearby dwarf galaxies with radio-selected accreting massive black holes (BHs), the majority of which are non-nuclear. We observed 111 galaxies using sensitive, high-resolution observations from the Karl G. Jansky Very Large Array (VLA) in its most extended A-configuration at X band (~8-12GHz), yielding a typical angular resolution of ~0.25" and rms noise of ~15{mu}Jy. Our targets were selected by crossmatching galaxies with stellar masses M_*_<=3x10^9^M_{sun}_ and redshifts z<0.055 in the NASA-Sloan Atlas with the VLA Faint Images of the Radio Sky at Twenty centimeters Survey. With our new high-resolution VLA observations, we detect compact radio sources toward 39 galaxies and carefully evaluate possible origins for the radio emission, including thermal HII regions, supernova remnants, younger radio supernovae, background interlopers, and active galactic nuclei (AGNs) in the target galaxies. We find that 13 dwarf galaxies almost certainly host active massive BHs, despite the fact that only one object was previously identified as having optical signatures of an AGN. We also identify a candidate dual radio AGN in a more massive galaxy system. The majority of the radio-detected BHs are offset from the center of the host galaxies, with some systems showing signs of interactions/mergers. Our results indicate that massive BHs need not always live in the nuclei of dwarf galaxies, confirming predictions from simulations. Moreover, searches attempting to constrain BH seed formation using observations of dwarf galaxies need to account for such a population of "wandering" BHs.
- ID:
- ivo://CDS.VizieR/J/A+AS/147/187
- Title:
- Second list of the Karachentsev catalog
- Short Name:
- J/A+AS/147/187
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Table2 presents the results of HI observations of 78 'nearby dwarf galaxies' from Karachentseva et al. (1999A&AS..135..221K) obtained with the 100-m radio telescope at Effelsberg. This survey covers an area limited by R.A.[14h,23h30] and Dec[-20d,+60d] including the nearest cosmic void : R.A.[18h38m], Dec[+18d], V_0_<1500km/s.
- ID:
- ivo://CDS.VizieR/J/MNRAS/431/194
- Title:
- Selecting IRAC counterparts to SMGs
- Short Name:
- J/MNRAS/431/194
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present a new submm/mm galaxy counterpart identification technique which builds on the use of Spitzer Infrared Array Camera (IRAC) colours as discriminators between likely counterparts and the general IRAC galaxy population. Using 102 radio- and Submillimeter Array-confirmed counterparts to AzTEC sources across three fields [Great Observatories Origins Deep Survey-North, -South and Cosmic Evolution Survey (COSMOS)], we develop a non-parametric IRAC colour-colour characteristic density distribution, which, when combined with positional uncertainty information via likelihood ratios, allows us to rank all potential IRAC counterparts around submillimetre galaxies (SMGs) and calculate the significance of each ranking via the reliability factor. We report all robust and tentative radio counterparts to SMGs, the first such list available for AzTEC/COSMOS, as well as the highest ranked IRAC counterparts for all AzTEC SMGs in these fields as determined by our technique. We demonstrate that the technique is free of radio bias and thus applicable regardless of radio detections. For observations made with a moderate beam size (~18"), this technique identifies ~85% of SMG counterparts. For much larger beam sizes (>~30"), we report identification rates of 33-49%. Using simulations, we demonstrate that this technique is an improvement over using positional information alone for observations with facilities such as AzTEC on the Large Millimeter Telescope and Submillimeter Common User Bolometer Array 2 on the James Clerk Maxwell Telescope.
- ID:
- ivo://CDS.VizieR/J/A+AS/116/157
- Title:
- SEST obs. of extragalactic radiosources
- Short Name:
- J/A+AS/116/157
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Flux densities of 155 extragalactic radio sources observed with the SEST telescope at 3mm and 1.3mm are presented. The observations were performed from October 1987 to June 1994. In addition to the flux density tables we have plotted the flux density curves for some of the most frequently observed sources.
- ID:
- ivo://CDS.VizieR/J/ApJS/192/15
- Title:
- Seven-year WMAP catalog
- Short Name:
- J/ApJS/192/15
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present updated estimates of Galactic foreground emission using seven years of WMAP data. Using the power spectrum of differences between multi-frequency template-cleaned maps, we find no evidence for foreground contamination outside of the updated (KQ85y7) foreground mask. We place a 15uK upper bound on rms foreground contamination in the cleaned maps used for cosmological analysis. Further, the cleaning process requires only three power-law foregrounds outside of the mask. We find no evidence for polarized foregrounds beyond those from soft (steep-spectrum) synchrotron and thermal dust emission; in particular we find no indication in the polarization data of an extra "haze" of hard synchrotron emission from energetic electrons near the Galactic center. We provide an updated map of the cosmic microwave background (CMB) using the internal linear combination method, updated foreground masks, and updates to point source catalogs using two different techniques. With additional years of data, we now detect 471 point sources using a five-band technique and 417 sources using a three-band CMB-free technique. In total there are 62 newly detected point sources, a 12% increase over the five-year release.
- ID:
- ivo://CDS.VizieR/J/ApJ/701/1398
- Title:
- SFR for starburst galaxies
- Short Name:
- J/ApJ/701/1398
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present a comparison of star formation rates (SFR) determined from mid-infrared 7.7um polycyclic aromatic hydrocarbon (PAH) luminosity [SFR(PAH)], from 1.4GHz radio luminosity [SFR(radio)], and from far-ultraviolet luminosity [SFR(UV)] for a sample of 287 starburst galaxies with z<0.5 having Spitzer IRS observations.
- ID:
- ivo://CDS.VizieR/J/A+AS/115/407
- Title:
- Short WSRT HI observations of spiral galaxies
- Short Name:
- J/A+AS/115/407
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We have obtained short HI observations of 60 late type spiral galaxies with the Westerbork Synthesis Radio Telescope (WSRT). Several HI properties are presented, including the radial surface density distribution of HI and a position-velocity map. When possible these are compared to those measured from single-dish observations. We confirm earlier results that there is no serious systematic difference between the WSRT and single-dish observations in total flux and linewidths.
- ID:
- ivo://CDS.VizieR/J/AJ/125/2411
- Title:
- SIRTF First-Look Survey
- Short Name:
- J/AJ/125/2411
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The First-Look Survey (FLS) of the Space Infrared Telescope Facility (SIRTF) will cover about 5deg^2^ centered on J2000.0 (17:18+59:30) in order to characterize the extragalactic infrared sky 2 orders of magnitude deeper than the IRAS survey. We expect that most of the FLS far-infrared ({lambda} = 160, 70, and 24 {mu}m) sources will be star-forming galaxies obeying the very tight far-infrared/radio correlation and will be continuum radio sources with flux densities S>~100{mu}Jy at {nu}=1.4GHz. Conversely, radio sources stronger than 100{mu}Jy are usually powered by star-forming galaxies, plus some active galactic nuclei, and most should be detectable by the SIRTF FLS. Thus, a sensitive radio survey can be used to select and identify most of the SIRTF FLS source population before launch. We used the B configuration of the VLA to make an image of the FLS area at {nu}=1.4GHz with {sigma}=~23{mu}Jy/beam rms fluctuations, {theta}=5'' resolution, and {sigma}_{alpha}_=~{sigma}_{delta}_=~0.5'' rms uncertainties in right ascension and declination. The resulting radio image and catalog of 3565 radio components with peak flux densities Sp>=5{sigma}=115{mu}Jy/beam have been released via the Web to expedite follow-up optical identification and spectroscopy.
- ID:
- ivo://CDS.VizieR/J/A+A/281/375
- Title:
- Small-size radio galaxies in clusters
- Short Name:
- J/A+A/281/375
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- (no description available)