- ID:
- ivo://CDS.VizieR/J/A+A/398/901
- Title:
- VLA survey at 6 cm in the Lockman Hole
- Short Name:
- J/A+A/398/901
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- A deep radio image was obtained with the Very Large Array at 6cm in the Lockman Hole, during three runs of eleven hours each on January 16, 17 and 19, 1999 at 4835 and 4885MHz with a bandwidth of 50MHz in C configuration. From these data a catalogue of 63 radio sources was extracted, having a maximum distance of 10arcmin from the field center and a peak flux density greater than 4.5 times the local rms noise. The noise level in the central part of the field is ~11{mu}Jy.
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Search Results
- ID:
- ivo://CDS.VizieR/J/AJ/98/64
- Title:
- VLA survey of Abell clusters of galaxies I.
- Short Name:
- J/AJ/98/64
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We report the results of a VLA survey at 20cm of a complete sample of nearby Abell clusters (D<=3). We have compiled an extensive catalog of cluster radio sources with S_20_>10mJy from a combination of our VLA observations and observations of similar resolution with the Westerbork Synthesis Radio Telescope (WSRT). Using these radio data and X-ray data from the Einstein observatory, we have analyzed the properties of these clusters. Unlike that previously suggested, no significant correlation is found between 20cm radio power and X-ray luminosity. There is weak evidence that richer clusters have a higher probability of radio emission. Based on Rood-Sastry morphological types of clusters, we do not find any strong evidence that regular-type clusters are statistically more likely to be radio loud than irregular-type clusters. However, Bautz-Morgan types I and II-III are found to have comparable radio-detection rates; but Bautz-Morgan Type III clusters are likely to have a lower radio-detection rate. A weak correlation between X-ray-cooling mass-accretion rates and radio powers was found for central, dominant galaxies in cooling-flow clusters. This might suggest that either cooling accretion directly fuels the central engine and/or cooling flows strongly interact with (e.g., confine) the radio plasma. In addition, radio sources associated with central dominant galaxies in cooling-flow clusters tend to be small in comparison with those in non-cooling-flow clusters. This might suggest that cooling flows tend to obstruct the propagation of radio jets from central, dominant galaxies.
- ID:
- ivo://CDS.VizieR/J/ApJ/698/740
- Title:
- VLA survey of CDF-S. III.
- Short Name:
- J/ApJ/698/740
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We discuss the X-ray properties of the radio sources detected in a deep 1.4 and 5GHz VLA Radio survey of the Extended Chandra Deep Field-South (E-CDFS). Among the 266 radio sources detected, we find 89 sources (1/3 of the total) with X-ray counterparts in the catalog of the 1Ms exposure of the central 0.08deg^2^ or in the catalog of the 250ks exposure of the 0.3deg^2^ E-CDFS field. For 76 (85%) of these sources, we have spectroscopic or photometric redshifts, and therefore we are able to derive their intrinsic properties from X-ray spectral analysis, namely intrinsic absorption and total X-ray luminosities. We find that the population of submillijansky radio sources with X-ray counterparts is composed of a mix of roughly 1/3 star-forming galaxies and 2/3 active galactic nuclei (AGNs).
- ID:
- ivo://CDS.VizieR/J/ApJS/179/71
- Title:
- VLA survey of the CDF-S I.
- Short Name:
- J/ApJS/179/71
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We report 20 and 6cm VLA deep observations of the CDF-S including the Extended CDF-S. We discuss the radio properties of 266 cataloged radio sources, of which 198 are above a 20cm completeness level reaching down to 43uJy at the center of the field. Survey observations made at 6cm over a more limited region cover the original CDF-S to a comparable level of sensitivity as the 20cm observations. Of 266 cataloged radio sources, 52 have X-ray counterparts in the CDF-S and a further 37 have counterparts in the E-CDF-S area not covered by the 1Ms exposure. Using a wide range of material, we have found optical or infrared counterparts for 254 radio sources, of which 186 have either spectroscopic or photometric redshifts. Three radio sources have no apparent counterpart at any other wavelength. Measurements of the 20cm radio flux density at the position of each CDF-S X-ray source detected a further 30 radio sources above a conservative 3{sigma} detection limit. X-ray and submillimeter observations have been traditionally used as a measure of AGN and star formation activity, respectively. These new observations probe the faint end of both the star formation and radio galaxy/AGN population, as well as the connection between the formation and evolution of stars and SMBHs.
- ID:
- ivo://CDS.VizieR/J/ApJ/663/164
- Title:
- VLT and ACS observations in RDCS J1252.9-2927
- Short Name:
- J/ApJ/663/164
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present results from an extensive spectroscopic survey, carried out with VLT FORS, and from an extensive multiwavelength imaging data set from the HST Advanced Camera for Surveys and ground-based facilities, of the cluster of galaxies RDCS J1252.9-2927.
- ID:
- ivo://CDS.VizieR/J/AJ/149/200
- Title:
- VRI photometry in NGC 7129
- Short Name:
- J/AJ/149/200
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- NGC7129 is a bright reflection nebula located in the molecular cloud complex near l=105.4{deg}, b=+9.9{deg}, about 1.15kpc distant. Embedded within the reflection nebula is a young cluster dominated by a compact grouping of four early-type stars: BD+65{deg}1638 (B3V), BD+65{deg}1637 (B3e), SVS 13 (B5e), and LkH{alpha} 234 (B8e). About 80 H{alpha} emission sources brighter than V~23 are identified in the region, many of which are presumably T Tauri star members of the cluster. We also present deep (V~23), optical (VR_C_I_C_) photometry of a field centered on the reflection nebula and spectral types for more than 130 sources determined from low dispersion, optical spectroscopy. The narrow pre-main sequence evident in the color-magnitude diagram suggests that star formation was rapid and coeval. A median age of about 1.8Myr is inferred for the H{alpha} and literature-identified X-ray emission sources having established spectral types, using pre-main sequence evolutionary models. Our interpretation of the structure of the molecular cloud and the distribution of young stellar objects is that BD+65{deg}1638 is primarily responsible for evacuating the blister-like cavity within the molecular cloud. LkH{alpha} 234 and several embedded sources evident in near-infrared adaptive optics imaging have formed recently within the ridge of compressed molecular gas. The compact cluster of low-mass stars formed concurrently with the early-type members, concentrated within a central radius of ~0.7pc. Star formation is simultaneously occurring in a semi-circular arc some ~3pc in radius that outlines remaining dense regions of molecular gas. High dispersion, optical spectra are presented for BD+65{deg}1638, BD+65{deg}1637, SVS 13, LkH{alpha} 234, and V350 Cep. These spectra are discussed in the context of the circumstellar environments inferred for these stars.
- ID:
- ivo://CDS.VizieR/J/ApJS/176/374
- Title:
- WARPS-II Cluster catalog. VII.
- Short Name:
- J/ApJS/176/374
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present the galaxy cluster catalog from the second, larger phase of the Wide Angle ROSAT Pointed Survey (WARPS), an X-ray selected survey for high-redshift galaxy clusters. WARPS is among the largest deep X-ray cluster surveys and is being used to study the properties and evolution of galaxy clusters. The WARPS-II sample contains 125 clusters serendipitously detected in a survey of 301 ROSAT PSPC pointed observations and covers a sky area of 56.7deg^2^. Of these 125 clusters, 53 have not been previously reported in the literature. We have nearly complete spectroscopic follow-up of the clusters, which range in redshift from z=0.029 to z=0.92 with a median redshift of z=0.29 and find 59 clusters with z>=0.3 (29 not previously reported in the literature) and 11 clusters with z>=0.6 (6 not previously reported). We also define a statistically complete subsample of 102 clusters above a uniform flux limit of 6.5x10^-14^ergs/cm^2^/s (0.5-2.0keV). Here we provide the cluster catalog and finder charts consisting of X-ray overlays on optical CCD images. We also compare our redshifts, fluxes, and detection methods to other similar published cluster surveys and find no serious issues with our measurements or completeness.
978. WARPS survey. VI.
- ID:
- ivo://CDS.VizieR/J/ApJS/140/265
- Title:
- WARPS survey. VI.
- Short Name:
- J/ApJS/140/265
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present in catalog form the optical identifications for objects from the first phase of the Wide Angle ROSAT Pointed Survey (WARPS). WARPS is a serendipitous survey of relatively deep, pointed ROSAT observations for clusters of galaxies. The X-ray source detection algorithm used by WARPS is Voronoi Tessellation and Percolation (VTP), a technique which is equally sensitive to point sources and extended sources of low surface brightness. WARPS-I is based on the central regions of 86 ROSAT PSPC fields, covering an area of 16.2 square degrees. We describe here the X-ray source screening and optical identification process for WARPS-I, which yielded 34 clusters at 0.06<z<0.75. Twenty-two of these clusters form a complete, statistically well-defined sample drawn from 75 of these 86 fields, covering an area of 14.1 square degrees, with a flux limit of F(0.5x2.0keV)=6.5x10^-14^erg/cm^2^/s. This sample can be used to study the properties and evolution of the gas, galaxy and dark matter content of clusters and to constrain cosmological parameters. We compare in detail the identification process and findings of WARPS to those from other recently published X-ray surveys for clusters, including RDCS, SHARC-Bright, SHARC-south, and the CfA 160deg^2^ survey.
- ID:
- ivo://CDS.VizieR/J/A+A/641/A162
- Title:
- Water maser data of 380 galaxies
- Short Name:
- J/A+A/641/A162
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Water megamaser emission at 22GHz has proven to be a powerful tool for astrophysical studies of active galactic nuclei (AGN) because it allows an accurate determination of the mass of the central black hole and of the accretion disc geometry and dynamics. However, after searches among thousands of galaxies, only ~200 of them have shown such spectroscopic features, most of them of uncertain classification. In addition, the physical and geometrical conditions under which a maser activates are still unknown. We characterize the occurrence of water maser emission in an unbiased sample of AGN by investigating the relation with the X-ray properties and the possible favourable geometry that is required to detect water maser. We searched for 22GHz maser emission in a hard X-ray selected sample of AGN, taken from the INTEGRAL/IBIS survey above 20keV. Only half of the 380 sources in the sample have water maser data. We also considered a volume-limited sub-sample of 87 sources, for which we obtained new observations with the Green Bank and Effelsberg telescopes (for 35 sources). We detected one new maser and increased its radio coverage to 75%. The detection rate of water maser emission in the total sample is 15+/-3%. This fraction increases to 19+/-5% for the complete sub-sample, especially when we consider type 2 (22+/-5% and 31+/-10% for the total and complete samples, respectively) and Compton-thick AGN (56+/-18% and 50+/-35% for the total and complete samples, respectively). No correlation is found between water maser and X-ray luminosity. We note that all types of masers (disc and jet) are associated with hard X-ray selected AGN. These results demonstrate that the hard X--ray selection may significantly enhance the maser detection efficiency over comparably large optical or infrared surveys. A possible decline in detection fraction with increasing luminosity might suggest that an extremely luminous nuclear environment does not favour maser emission. The large fraction of CT AGN with water maser emission could be explained in terms of geometrical effects. The maser medium would then be the very edge-on portion of the obscuring medium.
- ID:
- ivo://CDS.VizieR/J/A+A/501/851
- Title:
- WINGS JK photometry of 28 galaxy clusters
- Short Name:
- J/A+A/501/851
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- This is the third paper in a series devoted to the WIde-field Nearby Galaxy-cluster Survey (WINGS). WINGS is a long-term project aimed at gathering wide-field, multiband imaging and spectroscopy of galaxies in a complete sample of 77 X-ray selected, nearby clusters (0.04<z<0.07) located far from the galactic plane (|b|>=20{deg}). The main goal of this project is to establish a local reference sample for evolutionary studies of galaxies and galaxy clusters. This paper presents the near-infrared (J,K) photometric catalogs of 28 clusters of the WINGS sample and describes the procedures followed to construct them.
