- ID:
- ivo://CDS.VizieR/J/A+A/456/791
- Title:
- XMM-LSS field at 74 and 325MHz
- Short Name:
- J/A+A/456/791
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The XMM Large Scale Structure survey (XMM-LSS) is an X-ray survey aimed at studying the large scale structure of the Universe. The XMM-LSS field is currently being followed up using observations across a wide range of wavelengths, and in this paper we present the observational results of a low frequency radio survey of the XMM-LSS field using the Very Large Array at 74 and 325MHz. This survey will map out the locations of the extragalactic radio sources relative to the large scale structure as traced by the X-ray emission. This is of particular interest because radio galaxies and radio loud AGN show strong and complex interactions with their small and larger scale environment, and different classes of radio galaxies are suggested to lie at different places with respect to the large scale structure.
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Search Results
- ID:
- ivo://CDS.VizieR/J/A+A/490/879
- Title:
- XMM-LSS field optical identifications
- Short Name:
- J/A+A/490/879
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The XMM-Large Scale Structure survey field (XMM-LSS) is an extragalactic window surveyed in the X-ray with the XMM-Newton satellite. It has also been observed in the optical with the Canada-France Hawaii Telescope (CFHTLS survey), and in the infrared with the Spitzer Space Telescope (SWIRE survey). These surveys have been carried out to study the structure and evolution of both baryonic and dark matter on cosmological scales. In two previous papers, we presented deep low frequency radio surveys of the XMM-LSS field, with limiting flux density levels of ~4 and ~1.5mJy/beam at 325 and 610MHz respectively (5{sigma}). These radio surveys were motivated by the need to understand the various connections between the host galaxies of radio sources and their environments. In this paper, we identify optical counterparts to the low frequency radio sources, using the CFHTLS optical catalogue and images, that have an i-band limiting magnitude of i_AB_~25.
- ID:
- ivo://CDS.VizieR/J/ApJ/591/640
- Title:
- XMM-LSS low-frequency radio counterparts
- Short Name:
- J/ApJ/591/640
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The XMM Large-Scale Structure Survey (XMM-LSS) is a major project to map the large-scale structure of the universe out to cosmological distances. An 8x8 region will be surveyed by XMM with planned optical follow-up to produce a three-dimensional map of many hundreds of clusters out to a redshift of z=1. To explore the relation of the large-scale structure to the location and properties of extragalactic radio sources, the XMM-LSS project also includes a low-frequency radio survey of this region. This combination will provide unprecedented insight into how the radio source formation and evolution are affected by the local environment. Here we present preliminary results from our 325 and 74MHz surveys in this region. At 325MHz, we have a flux limit of 4mJy/beam, a resolution of 6.3", and a total of 256 source detections over 5.6deg^2^. At 74MHz, we have a flux limit of 275mJy/beam, a resolution of 30", and a total of 211 source detections over 110deg^2^. We describe these results and explore what they tell us about the population of extragalactic low-frequency radio sources. The 74MHz survey represents the first presentation of a deep, subarcminute resolution survey at such a low frequency. This was made possible by recent advances in both hardware and data reduction algorithms, which we describe in detail.
- ID:
- ivo://CDS.VizieR/J/MNRAS/352/91
- Title:
- XMM-Newton/2dF survey. IV.
- Short Name:
- J/MNRAS/352/91
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present an analysis of the X-ray spectral properties of 61 hard X-ray (2-8keV) selected sources from the bright XMM-Newton/2dF (f(2-8keV)>10^-14^erg/cm^2^/s) survey. This comprises nine XMMNewton pointings in the North Galactic Pole region (~1.6deg^2^) and overlaps with the SDSS, 2QZ and 2dFGRS surveys. Our sources contribute about 50 per cent of the 2-10keV X-ray background down to the flux limit of 10^-14^erg/cm^2^/s. The hardness ratio distribution of the sample suggests a deficit of heavily absorbed sources. Spectroscopic identifications exist for 34 sources.
- ID:
- ivo://CDS.VizieR/J/A+A/281/355
- Title:
- X-ray AGN content of Molonglo 408MHz survey
- Short Name:
- J/A+A/281/355
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The cross-correlation of a source list from the ROSAT All-Sky Survey with the Molonglo 408MHz survey (MRC) yields to a catalogue of 549 sources. The majority of the objects are quasars and radio galaxies with known optical counterparts; more than one third of the objects are optically unidentified.
- ID:
- ivo://CDS.VizieR/J/A+A/545/A66
- Title:
- X-ray and radio emission of type 1 AGNs
- Short Name:
- J/A+A/545/A66
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- X-ray emission from Active Galactic Nuclei (AGN) is dominated by the accretion disk around a supermassive black hole. The radio luminosity, however, has not such a clear origin except in the most powerful sources where jets are evident. The origin (and even the very existence) of the local bi-modal distribution in radio-loudness is also a debated issue. By analysing X-ray, optical and radio properties of a large sample of type 1 AGN and quasars (QSOs) up to z>2, where the bulk of this population resides, we aim to explore the interplay between radio and X-ray emission in AGN, in order to further our knowledge on the origin of radio emission, and its relation to accretion. We analyse a large (~800 sources) sample of type 1 AGN and QSOs selected from the 2XMMi XMM-Newton X-ray source catalogue, cross-correlated with the SDSS DR7 spectroscopic catalogue, covering a redshift range from z~0.3 to z~2.3. Supermassive black hole masses are estimated from the Mg II emission line, bolometric luminosities from the X-ray data, and radio emission or upper limits from the FIRST catalogue. Most of the sources accrete close to the Eddington limit and the distribution in radio-loudness does not appear to have a bi-modal behaviour. We confirm that radio-loud AGN are also X-ray loud, with an X-ray-to-optical ratio up to twice that of radio-quiet objects, even excluding the most extreme strongly jetted sources. By analysing complementary radio-selected control samples, we find evidence that these conclusions are not an effect of the X-ray selection, but are likely a property of the dominant QSO population. Our findings are best interpreted in a context where radio emission in AGN, with the exception of a minority of beamed sources, arises from very close to the accretion disk and is therefore heavily linked to X-ray emission. We also speculate that the radio-loud/radio-quiet dichotomy might either be an evolutionary effect that developed well after the QSO peak epoch, or an effect of incompleteness in small samples.
- ID:
- ivo://CDS.VizieR/J/A+A/568/A107
- Title:
- X-ray and radio images of SNR G351.0-5.4
- Short Name:
- J/A+A/568/A107
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- While searching the NRAO VLA Sky Survey (NVSS) for diffuse radio emission, we have serendipitously discovered extended radio emission close to the Galactic plane. The radio morphology suggests the presence of a previously unknown Galactic supernova remnant. An unclassified gamma-ray source detected by EGRET (3EG J1744-3934) is present in the same location and may stem from the interaction between high-speed particles escaping the remnant and the surrounding interstellar medium. Our aim is to confirm the presence of a previously unknown supernova remnant and to determine a possible association with the gamma-ray emission 3EG J1744-3934. We have conducted optical and radio follow-ups of the target using the Dark Energy Camera (DECam) on the Blanco telescope at Cerro Tololo Inter-American Observatory (CTIO) and the Giant Meterwave Radio Telescope (GMRT). We then combined these data with archival radio and gamma-ray observations.
- ID:
- ivo://CDS.VizieR/J/ApJ/613/393
- Title:
- X-ray and radio sources in {rho} Oph Core A
- Short Name:
- J/ApJ/613/393
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- A 96ks Chandra X-ray observation of {rho} Ophiuchus cloud core A detected 87 sources, of which 60 were identified with counterparts at other wavelengths. Simultaneous multifrequency Very Large Array (VLA) observations detected 31 radio sources at 6cm, of which 10 were also detected by Chandra. We report new radio detections of the optically invisible IR source WLY 2-11 and the faint H{alpha} emission line star Elias 24 (class II).
- ID:
- ivo://CDS.VizieR/J/MNRAS/379/260
- Title:
- X-ray clusters with radio emission
- Short Name:
- J/MNRAS/379/260
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- By combining the REFLEX and NORAS cluster data sets with the NVSS radio catalogue, we obtain a sample of 145, z<0.3, X-ray-selected clusters brighter than 3x10^-12^erg/s/cm^-2^ that show a central radio emission above 3mJy. For virial masses M_vir_<10^14.5^M_{sun}_, 11 clusters out of 12 (corresponding to 92 per cent of the systems) are inhabited by a central radio source.
- ID:
- ivo://CDS.VizieR/J/ApJ/726/20
- Title:
- X-ray emission from quasars
- Short Name:
- J/ApJ/726/20
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present the results of an investigation into the X-ray properties of radio-intermediate and radio-loud quasars (RIQs and RLQs, respectively). We combine large, modern optical (e.g., SDSS) and radio (e.g., FIRST) surveys with archival X-ray data from Chandra, XMM-Newton, and ROSAT to generate an optically selected sample that includes 188 RIQs and 603 RLQs. This sample is constructed independently of X-ray properties but has a high X-ray detection rate (85%); it provides broad and dense coverage of the l-z plane, including at high redshifts (22% of objects have z=2-5), and it extends to high radio-loudness values (33% of objects have R*=3-5, using logarithmic units). We measure the "excess" X-ray luminosity of RIQs and RLQs relative to radio-quiet quasars (RQQs) as a function of radio loudness and luminosity, and parameterize the X-ray luminosity of RIQs and RLQs both as a function of optical/UV luminosity and also as a joint function of optical/UV and radio luminosity. RIQs are only modestly X-ray bright relative to RQQs; it is only at high values of radio loudness (R*>~3.5) and radio luminosity that RLQs become strongly X-ray bright.
