- ID:
- ivo://CDS.VizieR/J/other/Ap/54.147
- Title:
- Study of 230 IRAS-FSC galaxies
- Short Name:
- J/other/Ap/54.14
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- From the cross-correlation of the IRAS FSC catalog with the radio FIRST catalog, 230 infrared galaxies were selected having optical classifications and redshifts from SDSS and NED. To understand the nature of these objects we have compared them with a sample of bright ULIRGs with fluxes f>1Jy at 60-micron and with 14 optically faint IRAS FSC galaxies, showing that IRAS galaxies are not always strong infrared sources. We also have calibrated Star Formation Rates based on luminosities of the PAH feature at 7.7-micron and 1.4GHz radio flux densities, which confirmed the consistency between these two SFRs. We have estimated the extinction for our 230 objects using SFRs calibrated from the PAH feature compared to ultraviolet flux, which shows that only 1% of the ultraviolet continuum typically escapes extinction by dust within a starburst. As our 230 galaxies have no spectra available from Spitzer Space Telescope (SST) archive, to estimate the infrared flux at 7.7 (for SB galaxies) or 8.0 (for AGN and composite) micron, we have used the median ratios of the IRAS fluxes at 25-micron to fluxes at 7.7 or 8.0-micron estimated for each 41.0<logL(IR)<41.9, 42.0<logL(IR)<42.9, 43.0<logL(IR)<43.9, 44.0<logL(IR)<44.9, and 45.0<logL(IR)<45.9 luminosity bins, using objects having spectra from SST archive.
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Search Results
- ID:
- ivo://CDS.VizieR/J/A+A/644/A85
- Title:
- Sub-milliarcsecond imaging of 3C111
- Short Name:
- J/A+A/644/A85
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Flares in radio-loud active galactic nuclei (AGNs) are thought to be associated with the injection of fresh plasma into the compact jet base. Such flares are usually strongest and appear earlier at shorter radio wavelengths. Hence, very long baseline interferometry (VLBI) at millimeter (mm)-wavelengths is the best-suited technique for studying the earliest structural changes of compact jets associated with emission flares. Aims. We study the morphological changes of the parsec-scale jet in the nearby (z=0.049) gamma-ray bright radio galaxy 3C 111 following a flare that developed into a major radio outburst in 2007. We analyse three successive observations of 3C 111 at 86 GHz with the Global mm-VLBI Array (GMVA) between 2007 and 2008 which yield a very high angular resolution of ~45 muas. In addition, we make use of single-dish radio flux density measurements from the F-GAMMA and POLAMI programmes, archival single-dish and VLBI data. We resolve the flare into multiple plasma components with a distinct morphology resembling a bend in an otherwise remarkably straight jet. The flare-associated features move with apparent velocities of ~4.0c to ~4.5c and can be traced also at lower frequencies in later epochs. Near the base of the jet, we find two bright features with high brightness temperatures up to ~10^11^K, which we associate with the core and a stationary feature in the jet. The flare led to multiple new jet components indicative of a dynamic modulation during the ejection. We interpret the bend-like feature as a direct result of the outburst which makes it possible to trace the transverse structure of the jet. In this scenario, the components follow different paths in the jet stream consistent with expectations for a spine-sheath structure, which is not seen during intermediate levels of activity. The possibility of coordinated multiwavelength observations during a future bright radio flare in 3C 111 makes this source an excellent target for probing the radio-gamma-ray connection.
- ID:
- ivo://CDS.VizieR/J/ApJ/599/1049
- Title:
- Supergiant molecular complexes in the Antennae
- Short Name:
- J/ApJ/599/1049
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We have used previously published observations of the CO emission from the Antennae (NGC 4038/4039) to study the detailed properties of the supergiant molecular complexes with the goal of understanding the formation of young massive star clusters.
- ID:
- ivo://CDS.VizieR/J/ApJ/430/467
- Title:
- Superluminal motions for extragalactic sources
- Short Name:
- J/ApJ/430/467
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Table 1 lists the 66 extragalactic sources for which we have been able to find multiepoch VLBI internal proper motion observations in the literature, or for which we are currently preparing a paper.
- ID:
- ivo://CDS.VizieR/J/A+AS/75/67
- Title:
- Survey around the North Ecliptic Pole at 11 cm
- Short Name:
- J/A+AS/75/67
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- This catalog contains a survey of a rectangular area of 10x6 degrees in galactic coordinates (95.5{deg} < l < 101.5{deg} ; 28{deg} < b < 38{deg}) in the radio continuum in the direction of the north ecliptic pole (RA=18h, Dec=66.5{deg}) at 11.1 cm wavelength. The survey was conducted with the 100m radio telescope of the Max Planck Institut fur Radioastronomie. 469 sources were detected with an integrated flux density greater than 11 mJy, and with an angular resolution of 4.35'. The survey is believed to be complete to at least the 35 mJy level and can be used for comparison with deep surveys in other wavelengths of this area.
- ID:
- ivo://CDS.VizieR/J/ApJS/98/369
- Title:
- Survey of Markarian galaxies
- Short Name:
- J/ApJS/98/369
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Results are presented from a multifrequency radio continuum survey of Markarian galaxies (MRKs) and are supplemented by IRAS infrared data from the Faint Source Survey. Radio data are presented for 899 MRKs observed at {nu}=4.755GHz with the NRAO-Green Bank 300 foot (91m) telescope, including nearly 88% of those objects in Markarian list VI-XIV. In addition, 1.415GHz measurements of 258 MRKs, over 30% of the MRKs accessible from NAIC-Arecibo, are reported. Radio continuum observations of smaller numbers of MRKs were made at 10.63GHz and at 23.1GHz and are also presented.
- ID:
- ivo://CDS.VizieR/J/ApJ/740/98
- Title:
- Synchroton peak for blazars and radio galaxies
- Short Name:
- J/ApJ/740/98
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We revisit the concept of a blazar sequence that relates the synchrotron peak frequency ({nu}_peak_) in blazars with synchrotron peak luminosity (L_peak_, in {nu}L_{nu}_) using a large sample of radio-loud active galactic nuclei. We present observational evidence that the blazar sequence is formed from two populations in the synchrotron {nu}_peak_-L_peak_ plane, each forming an upper edge to an envelope of progressively misaligned blazars, and connecting to an adjacent group of radio galaxies having jets viewed at much larger angles to the line of sight. When binned by jet kinetic power (L_kin_; as measured through a scaling relationship with extended radio power), we find that radio core dominance decreases with decreasing synchrotron L_peak_, revealing that sources in the envelope are generally more misaligned. We find population-based evidence of velocity gradients in jets at low kinetic powers (~10^42^-10^44.5^erg/s), corresponding to Fanaroff-Riley (FR) I radio galaxies and most BL Lac objects. These low jet power "weak-jet" sources, thought to exhibit radiatively inefficient accretion, are distinguished from the population of non-decelerating, low synchrotron-peaking (LSP) blazars and FR II radio galaxies ("strong" jets) which are thought to exhibit radiatively efficient accretion. The two-population interpretation explains the apparent contradiction of the existence of highly core-dominated, low-power blazars at both low and high synchrotron peak frequencies, and further implies that most intermediate synchrotron peak sources are not intermediate in intrinsic jet power between LSP and high synchrotron-peaking (HSP) sources, but are more misaligned versions of HSP sources with similar jet powers.
- ID:
- ivo://CDS.VizieR/J/A+A/569/A115
- Title:
- TANAMI monitoring of Centaurus A.
- Short Name:
- J/A+A/569/A115
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Centaurus A (Cen A) is the closest radio-loud active galactic nucleus. Very Long Baseline Interferometry (VLBI) enables us to study the spectral and kinematic behavior of the radio jet-counterjet system on milliarcsecond scales, providing essential information for jet emission and propagation models. In the framework of the TANAMI monitoring, we investigate the kinematics and complex structure of Cen A on subparsec scales. We have been studying the evolution of the central parsec jet structure of Cen A for over 3.5-years. The proper motion analysis of individual jet components allows us to constrain jet formation and propagation and to test the proposed correlation of increased high-energy flux with jet ejection events. Cen A is an exceptional laboratory for such a detailed study because its proximity translates to unrivaled linear resolution, where one milliarcsecond corresponds to 0.018pc. As a target of the southern-hemisphere VLBI monitoring program TANAMI, observations of Cen A are done approximately every six months at 8.4GHz with the Australian Long Baseline Array (LBA) and associated telescopes in Antarctica, Chile, New Zealand, and South Africa, complemented by quasi-simultaneous 22.3GHz observations. The first seven epochs of high-resolution TANAMI VLBI observations at 8.4GHz of Cen A are presented, resolving the jet on (sub-)milliarcsecond scales. They show a differential motion of the subparsec scale jet with significantly higher component speeds farther downstream where the jet becomes optically thin. We determined apparent component speeds within a range of 0.1c to 0.3c and identified long-term stable features. In combination with the jet-to-counterjet ratio, we can constrain the angle to the line of sight to {theta}~12{deg}-45{deg}. The high-resolution kinematics are best explained by a spine-sheath structure supported by the downstream acceleration occurring where the jet becomes optically thin. On top of the underlying, continuous flow, TANAMI observations clearly resolve individual jet features. The flow appears to be interrupted by an obstacle causing a local decrease in surface brightness and circumfluent jet behavior. We propose a jet-star interaction scenario to explain this appearance. The comparison of jet ejection times to high X-ray flux phases yields a partial overlap of the onset of the X-ray emission and increasing jet activity, but the limited data do not support a robust correlation.
- ID:
- ivo://CDS.VizieR/J/A+A/627/A148
- Title:
- TANAMI radio galaxies I
- Short Name:
- J/A+A/627/A148
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- In the framework of the TANAMI multi-wavelength and VLBI monitoring, we study the evolution of the parsec-scale radio emission in radio galaxies in the southern hemisphere and their relationship to the gamma-ray properties of the sources. Our study investigates systematically, for the first time, the relationship between the two energy regimes in radio galaxies. In this first paper, we focus on Fermi-LAT-detected sources. The TANAMI program monitors a large sample of radio-loud AGN at 8.4GHz and 22.3GHz with the Australian Long Baseline Array(LBA) and associated telescopes in Antarctica, Chile, New Zealand and South Africa. We perform a kinematic analysis for five gamma-ray detected radio galaxies using multi-epoch 8.4 GHz VLBI images, deriving limits on intrinsic jet parameters such as speed and viewing angle. We analyzed103 months of Fermi-LAT data in order to study possible connections between the gamma-ray properties and the pc-scale jets of Fermi-LAT-detected radio galaxies, both in terms of variability and average properties. We discuss the individual source results and draw preliminary conclusions on sample properties including published VLBI results from the MOJAVE survey, with a total of fifteen sources. We find that the first gamma-ray detection of Pictor A might be associated with the passage of a new VLBI component through the radio core, which appears to be a defining feature of high-energy emitting Fanaroff-Riley type II radio galaxies. For the peculiar AGN PKS 0521-36, we detect subluminal parsec-scale jet motions, and we confirm the presence of fast gamma-ray variability in the source down to timescales of 6 hours, which is not accompanied by variations in the VLBI jet. We robustly confirm the presence of significant superluminal motion, up to {beta}_app_~3, in the jet of the TeV radio galaxy PKS 0625-35. Our VLBI results constrain the jet viewing angle to be {theta}<53{deg}, allowing for the possibility of a closely aligned jet. Finally, by analyzing the first pc-scale multi-epoch images of the prototypical Compact Symmetric Object (CSO) PKS 1718-649, we place an upper limit on the separation speed between the two mini-lobes, which in turn allows us to derive a lower limit on the age of the source.Conclusions.We can draw some preliminary conclusions on the relationship between pc-scale jets and gamma-ray emission in radio galaxies, basedonFermi-LAT-detected sources with available multi-epoch VLBI measurements. We find that the VLBI core flux density correlates with the gamma-ray flux, as seen in blazars. On the other hand, the gamma-ray luminosity does not show any dependence on the core brightness temperature and core dominance, two common indicators of jet Doppler boosting. This seems to indicate that gamma-ray emission in radio galaxies is not driven by orientation-dependent effects, as in blazars, which is consistent with the unified model of jetted AGN.
- ID:
- ivo://CDS.VizieR/J/A+A/641/A152
- Title:
- TANAMI radio galaxies II
- Short Name:
- J/A+A/641/A152
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- This is the second paper in our series studying the evolution of parsec-scale radio emission in radio galaxies in the southern hemisphere. Following our study of the radio and high-energy properties of gamma-ray-emitting sources, here we investigate the kinematic and spectral properties of the parsec-scale jets of radio galaxies that have not yet been detected by the Fermi Large Area Telescope (Fermi-LAT) instrument on board NASA's Fermi Gamma-ray Space Telescope. For many sources, these results represent the first milliarcsecond resolution information in the literature. These studies were conducted within the framework of the Tracking Active Nuclei with Austral Milliarcsecond Interferometry (TANAMI) monitoring program and in the context of high-energy gamma-ray observations from Fermi-LAT. We take advantage of the regular 8.4GHz and 22.3GHz Very Long Baseline Interferometry (VLBI) observations provided by the TANAMI monitoring program, and explore the kinematic properties of six gamma-ray-faint radio galaxies. We complement this with ~8.5 years of Fermi-LAT data, deriving updated upper limits on the gamma-ray emission from this subsample of TANAMI radio galaxies. We include publicly available VLBI kinematics of gamma-ray-quiet radio galaxies monitored by the MOJAVE program and perform a consistent Fermi-LAT analysis. We combine these results with those from our previous paper to construct the largest sample of radio galaxies with combined VLBI and gamma-ray measurements to date. The connection between parsec-scale jet emission and high-energy properties in the misaligned jets of radio galaxies is explored. We report for the first time evidence of superluminal motion up to beta_app_=3.6 in the jet of the gamma-ray-faint radio galaxy PKS 2153-69. We find a clear trend of higher apparent speed as a function of distance from the jet core, which indicates that the jet is still being accelerated on scales of tens of parsecs, or ~10^5^R_{sun}_, corresponding to the end of the collimation and acceleration zone in nearby radio galaxies. We find evidence of subluminal apparent motion in the jets of PKS 1258-321 and IC 4296, and no measurable apparent motion for PKS 1549-79, PKS 1733-565 and PKS 2027-308. For all these sources, TANAMI provides the first multi-epoch kinematic analysis on parsec scales. We then compare the VLBI properties of gamma-ray-detected and undetected radio galaxies, and find that the two populations show a significantly different distribution of median core flux density, and, possibly, of median core brightness temperature. In terms of correlation between VLBI and gamma-ray properties, we find a significant correlation between median core flux density and gamma-ray flux, but no correlation with typical Doppler boosting indicators such as median core brightness temperature and core dominance. Our study suggests that high-energy emission from radio galaxies is related to parsec-scale radio emission from the inner jet, but is not driven by Doppler boosting effects, in contrast to the situation in their blazar counterparts. This implies that gamma-ray loudness does not necessarily reflect a higher prevalence of boosting effects.
