- ID:
- ivo://CDS.VizieR/J/ApJ/317/102
- Title:
- Cancer cluster 1.4GHz continuum sources
- Short Name:
- J/ApJ/317/102
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We report on 1.4GHZ continuum observations for 11 VLA fields, using the D-configuration, which contain the A group of the Cancer Cluster. Sixteen Zwicky spiral galaxies in the Cancer Cluster were detected, but no ellipticals. We corroborate the finding that spiral galaxies with close companions tend to have enhanced radio emission. Over 200 continuum sources beyond the Cancer Cluster are tabulated. The spectral index (relative to 610MHz) is given for many of the sources, including some of the Zwicky galaxies. There is a suggestion for a nonuniform number surface-density distribution of the sources, not correlated with the Cancer Cluster. Possible predictions of such nonuniformities, from assumptions on " super-superclusters," are discussed.
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Search Results
- ID:
- ivo://CDS.VizieR/J/A+A/647/A63
- Title:
- 4C52.37 and 3C 293 parsec-scale HI outflows
- Short Name:
- J/A+A/647/A63
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Massive outflows of neutral atomic hydrogen (HI) have been observed in absorption in a number of radio galaxies and are considered a signature of active galactic nucleus (AGN) feedback. These outflows on kiloparsec scales have not been investigated in great detail as they require high-angular-resolution observations to be spatially resolved. In some radio AGN, they are likely to be the result of the radio jets interacting with the interstellar medium. We have used the global very-long-baseline-interferometry (VLBI) array to map the HI outflow in a small sample of young and restarted radio galaxies that we previously observed with the Very Large Array (VLA) and the Westerbork Synthesis Radio Telescope (WSRT) at a lower resolution. Here we report on our findings for 4C 52.37 and 3C 293 and we discuss the sample including the previously published 4C 12.50 and 3C 236. For 4C 52.37, we present the first ever HI VLBI observations, which recovered the majority of the outflowing HI gas in the form of clouds toward the central 100pc of the AGN. The clouds are blueshifted by up to ~600km/s with respect to the systemic velocity. 3C 293 is largely resolved out in our VLBI observation, but toward the VLBI core we detect some outflowing HI gas blueshifted with respect to the systemic velocity by up to ~300km/s. We also find indications of outflowing gas toward the other parts of the western lobe suggesting that the HI outflow is extended. Overall, we find that the fraction of HI gas recovered by our VLBI observations varies significantly within our sample, ranging from complete (4C 12.50) to marginal (3C 293). However, in all cases we find evidence for a clumpy structure of both the outflowing and the quiescent gas, consistent with predictions from numerical simulations. All the outflows include at least a component of relatively compact clouds with masses in the range of 10^4^-10^5^M_{sun}_. The outflowing clouds are often already observed at a few tens of parsecs (in projection) from the core. We find indications that the HI outflow might have a diffuse component, especially in larger sources. Our results support the interpretation that we observe these AGNs at different stages in the evolution of the interaction between the jet and the interstellar medium and this is reflected in the properties of the outflowing gas as predicted by numerical simulations.
- ID:
- ivo://CDS.VizieR/J/AJ/153/157
- Title:
- Candidate ICRF flat-spectrum radio sources. III.
- Short Name:
- J/AJ/153/157
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- In extending our spectroscopic program, which targets sources drawn from the International Celestial Reference Frame (ICRF) Catalog, we have obtained spectra for ~160 compact, flat-spectrum radio sources and determined redshifts for 112 quasars and radio galaxies. A further 14 sources with featureless spectra have been classified as BL Lac objects. Spectra were obtained at three telescopes: the 3.58m European Southern Observatory New Technology Telescope, and the two 8.2m Gemini telescopes in Hawaii and Chile. While most of the sources are powerful quasars, a significant fraction of radio galaxies is also included from the list of non-defining ICRF radio sources.
- ID:
- ivo://CDS.VizieR/J/A+A/461/823
- Title:
- Candidate Ly{alpha} emitting galaxies
- Short Name:
- J/A+A/461/823
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present the results of a large program conducted with the Very Large Telescope and augmented by observations with the Keck telescope to search for forming clusters of galaxies near powerful radio galaxies at 2.0<z<5.2. Besides MRC 1138-262 at z=2.16, the radio galaxy observed in our pilot program, we obtained narrow- and broad-band images of eight radio galaxies and their surroundings. The imaging was used to select candidate Ly{alpha} emitting galaxies in ~3x3Mpc^2^ areas near the radio galaxies. A total of 300 candidate emitters were found with a rest-frame Ly{alpha} equivalent width of EW0>15{AA} and significance Sigma{equiv.to}(EW0/DEW0)>3. Follow-up spectroscopy was performed on 152 candidates in seven of the radio galaxy fields. Of these, 139 were confirmed to be Ly{alpha} emitters, four were low redshift interlopers and nine were non-detections. With the adopted criteria the success rate is 139/152=91%. In addition, 14 objects with EW0<15 and/or Sigma<3 were confirmed to be Ly{alpha} emitters. Combined with the 15 Ly{alpha} emitters near MRC 1138-262, we have determined Ly{alpha} redshifts for 168 objects near eight radio galaxies.
- ID:
- ivo://CDS.VizieR/J/A+A/638/A29
- Title:
- 3C388 145, 392, 614, 1400 and 4850MHz images
- Short Name:
- J/A+A/638/A29
- Date:
- 23 Mar 2022 16:29:17
- Publisher:
- CDS
- Description:
- Restarted radio galaxies represent a unique tool to investigate the duty cycle of the jet activity in Active Galactic Nuclei. Due to a sharp discontinuity of the GHz spectral index distribution within its lobes, the radio galaxy 3C388 has for long being claimed to be a peculiar example of AGN with multi-epoch activity The goal of this work is to perform for the first time a spatially resolved study of the radio spectrum of this source down to MHz-frequencies, in order to investigate its radiative age and constrain its duty cycle. We have used new low frequency observations at 144MHz performed with the Low Frequency Array and at 350MHz performed with the Very Large Array combined with archival data at higher frequencies (614, 1400, 4850MHz). Results. We find that the spectral indices in the lower frequency range 144-614MHz have flatter values ({alpha}_low_~0.55-1.14) than those observed in the higher frequency range 1400-4850MHz ({alpha}_high_~0.75-1.57) but follow the same distribution across the lobes, with a systematic steepening towards the edges. However, the spectral shape throughout the source is not uniform and often deviates from standard models. This suggests that mixing of different particle populations is occurring, although it remains difficult to understand whether this is caused by observational limitations (insufficient spatial resolution and/or projection effects) or by the intrinsic presence of multiple particle populations, possibly related to the two different outbursts. By using single-injection radiative models we compute that the total source age is <~80Myr and that the duty cycle is about t_on_/t_tot_~60%, which is enough to prevent the intracluster medium from cooling according to X-ray estimates. While to date the radio spectral distribution of 3C388 remains a rare case among radio galaxies, multi-frequency surveys performed with new generation instruments will soon allow us to investigate whether more sources with the same characteristics do actually exist.
- ID:
- ivo://CDS.VizieR/J/other/RAA/19.127
- Title:
- C- and S-shaped radio galaxies
- Short Name:
- J/other/RAA/19.1
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We study the environment of radio galaxies with different morphological types using the Proctor sample, which was built from the Faint Images of the Radio Sky at Twenty-Centimeters (FIRST) survey archive. Among the 15 radio galaxy types classified by Proctor, 199 C-shaped (i.e., wide- or narrow-angle tail) and 203 S-shaped (i.e., S- or Z-shaped) sources are selected in this work, which are located in the redshift range of 0.02<z<1, because these two subsamples are relatively larger than the other subsamples in the Proctor sample. By cross-matching these radio galaxies with the optical sources drawn from the Sloan Digital Sky Survey (SDSS) database and counting the SDSS sources with an r-band absolute magnitude brighter than -19 located within a 0.5Mpc distance around each source (i.e., the richness), we find that the fraction of C-shaped sources with a richness above 10 is larger than that of S-shaped sources. We have also correlated the radio galaxies in our sample with the brightest cluster galaxies (BCGs) defined in the NASA/IPAC Extragalactic Database (NED), and infer that the C-shaped sources are more likely to be BCGs than the S-shaped sources. These results support the idea that C-shaped radio galaxies often reside in a richer environment than radio galaxies with other morphological types.
- ID:
- ivo://CDS.VizieR/VII/255
- Title:
- Catalog of radio galaxies with z>0.3
- Short Name:
- VII/255
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- This catalog groups the 2442 galaxies making up the sample of distant galaxies prepared by the authors published as 3 papers in 2009: radio data (paper I, table1), photometric data (paper II, table2), and angular sizes (paper III, table 3). The sample of distant (z>0.3) radio galaxies is aimed at application in cosmological tests. It was created using NED, SDSS, and CATS databases, and is assumed to be cleaned from objects with quasar properties.
- ID:
- ivo://CDS.VizieR/J/A+AS/131/73
- Title:
- Catalogue of HI maps of galaxies. I.
- Short Name:
- J/A+AS/131/73
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- A catalogue is presented of galaxies having large-scale observations in the HI line. This catalogue collects from the literature the information that characterizes the observations in the 21-cm line and the way that these data were presented by means of maps, graphics and tables, for showing the distribution and kinematics of the gas. It contains furthermore a measure of the HI extension that is detected at the level of the maximum sensitivity reached in the observations. This catalogue is intended as a guide for references on the HI maps published in the literature from 1953 to 1995 and is the basis for the analysis of the data presented in Paper II (Cat. <J/A+AS/131/77>).
- ID:
- ivo://CDS.VizieR/J/A+AS/131/77
- Title:
- Catalogue of HI maps of galaxies. II.
- Short Name:
- J/A+AS/131/77
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We use some of the maps of the catalogue presented in Paper I (Cat. <J/A+AS/131/73>) to provide some evidence for global conditions that must be fulfilled by the galaxies to have extended hydrogen. For this purpose, we tried to find possible connections between the HI gas extension and other properties of the galaxies (morphological type, surface brightness, gas density, etc.). With isophotal hydrogen diameters of a large sample, we could observe that optically smaller galaxies seem to have greater relative HI extensions. By means of the relation with the apparent HI surface density, we found an expression that should provide a rough estimate of the gas extension. With respect to the dependence on morphological type, we could not find any significant correlation either for the real HI surface density or the relative gas extension. Nevertheless, whereas for spiral and irregular galaxies the real HI surface density exhibits a broad range of values, the values are rather lower for elliptical and S0 galaxies.
- ID:
- ivo://CDS.VizieR/J/A+A/405/5
- Title:
- Catalogue of ISM content of normal galaxies
- Short Name:
- J/A+A/405/5
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We have compiled a catalogue of the gas content for a sample of 1916 galaxies, considered to be a fair representation of normality. The definition of a normal galaxy adopted in this work implies that we have purposely excluded from the catalogue galaxies having distorted morphology (such as interaction bridges, tails or lopsidedness) and/or any signature of peculiar kinematics (such as polar rings, counterrotating disks or other decoupled components). In contrast, we have included systems hosting active galactic nuclei (AGN) in the catalogue. This catalogue revises previous compendia on the ISM content of galaxies published by Bregman et al. (1992ApJ...387..484B) and Casoli et al. (1998A&A...331..451C), and compiles data available in the literature from several small samples of galaxies. Masses for warm dust, atomic and molecular gas, as well as X-ray luminosities have been converted to a uniform distance scale taken from the Catalogue of Principal Galaxies (PGC). We have used two different normalization factors to explore the variation of the gas content along the Hubble sequence: the blue luminosity (LB) and the square of linear diameter (D_25_^2^). Our catalogue significantly improves the statistics of previous reference catalogues and can be used in future studies to define a template ISM content for normal galaxies along the Hubble sequence.
