- ID:
- ivo://CDS.VizieR/J/A+A/651/A98
- Title:
- M31 C-band (6.6GHz) Sardinia radio tel. map
- Short Name:
- J/A+A/651/A98
- Date:
- 17 Jan 2022 11:45:00
- Publisher:
- CDS
- Description:
- The Andromeda galaxy is the best known large galaxy besides our own Milky Way. Several images and studies exist at all wavelengths from radio to hard X-ray. Nevertheless, only few observations are available in the microwave range where its average radio emission reaches the minimum. In this paper we want to study the radio morphology of the galaxy, decouple thermal from non-thermal emission and extract the star formation rate. We also aim to derive a complete catalogue of radio sources for the mapped patch of sky. We have observed the Andromeda galaxy with the Sardinia Radio Telescope at 6.6 GHz with very high sensitivity and angular resolution, and an unprecedented sky coverage. Using new 6.6GHz data and Effelsberg radio telescope ancillary data, we confirm that, globally, the spectral index assumes a value of ~0.7-0.8, while in the star forming regions it decreases to ~0.5. By disentangling (gas) thermal and non-thermal emission, we found that at 6.6GHz, thermal emission follows the distribution of HII regions around the ring. Non-thermal emission, within the ring, appears to be more uniform and smooth than thermal emission, due to the diffusion of the cosmic ray electrons away from their birthplaces. Hence the magnetic fields are nearly constant in intensity. Based on the thermal emission map, we have calculated a star formation rate map. Integrating within a radius of R_max_=15kpc, we obtained a total star formation rate of 0.19+/-0.01M*/yr in agreement with previous results in literature. Finally, we correlated our radio data with Infrared images of the Andromeda galaxy. We found an unexpected high correlation between non-thermal and MIR data in the central region, with a correlation parameter r=0.93. Finally, by computing the logarithmic 24um/21cm ratio q_24um_, we found a decreasing trend with increasing galactocentric distance and an increasing dispersion. The logarithmic FIR/radio ratio is found to be 2.41+/-0.04.
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Search Results
- ID:
- ivo://CDS.VizieR/J/A+A/595/L8
- Title:
- MCG+07-47-10 total intensity image at 322MHz
- Short Name:
- J/A+A/595/L8
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Standard galaxy formation models predict that large-scale double-lobed radio sources, known as DRAGNs, will always be hosted by elliptical galaxies. In spite of this, in recent years a small number of spiral galaxies have also been found to host such sources. These so-called spiral DRAGNs are still extremely rare, with only ~5 cases being widely accepted. Here we report on the serendipitous discovery of a new spiral DRAGN in data from the Giant Metrewave Radio Telescope (GMRT) at 322MHz. The host galaxy, MCG+07-47-10, is a face-on late-type Sbc galaxy with distinctive spiral arms and prominent bulge suggesting a high black hole mass. Using WISE infra-red and GALEX UV data we show that this galaxy has a star formation rate of 0.16-0.75M_{sun}_/yr, and that the radio luminosity is dominated by star-formation. We demonstrate that this spiral DRAGN has similar environmental properties to others of this class, but has a comparatively low radio luminosity of L_1.4GHz_=1.12x10^22^W/Hz, two orders of magnitude smaller than other known spiral DRAGNs. We suggest that this may indicate the existence of a previously unknown low-luminosity population of spiral DRAGNS.
- ID:
- ivo://CDS.VizieR/J/MNRAS/435/650
- Title:
- 325MHz GMRT survey of Herschel-ATLAS/GAMA fields
- Short Name:
- J/MNRAS/435/650
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We describe a 325MHz survey, undertaken with the Giant Metrewave Radio Telescope (GMRT), which covers a large part of the three equatorial fields at 9, 12 and 14.5h of right ascension from the Herschel-Astrophysical Terahertz Large Area Survey (H-ATLAS) in the area also covered by the Galaxy And Mass Assembly (GAMA) survey. The full data set, after some observed pointings were removed during the data reduction process, comprises 212 GMRT pointings covering ~90deg^2^ of sky. We have imaged and catalogued the data using a pipeline that automates the process of flagging, calibration, self-calibration and source detection for each of the survey pointings. The resulting images have resolutions of between 14 and 24-arcsec and minimum rms noise (away from bright sources) of ~1mJy/beam, and the catalogue contains 5263 sources brighter than 5{sigma}. We investigate the spectral indices of GMRT sources which are also detected at 1.4GHz and find them to agree broadly with previously published results; there is no evidence for any flattening of the radio spectral index below S_1.4_=10mJy. This work adds to the large amount of available optical and infrared data in the H-ATLAS equatorial fields and will facilitate further study of the low-frequency radio properties of star formation and AGN activity in galaxies out to z~1.
- ID:
- ivo://CDS.VizieR/VIII/98
- Title:
- 180MHz Murchison Commissioning Survey (MWACS)
- Short Name:
- VIII/98
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The Murchison Widefield Array Commissioning Survey (MWACS) is a ~6100deg^2^ 104-196MHz radio sky survey performed with the Murchison Widefield Array during instrument commissioning between 2012 September and 2012 December. The data were taken as meridian drift scans with two different 32-antenna sub-arrays that were available during the commissioning period. The data were combined in the visibility plane before being imaged, and then mosaicked. The survey covers approximately 20.5h<RA<8.5h, -58{deg}<Dec<-14{deg} over three frequency bands centred on 119, 150 and 180MHz. The survey has 3arcmin angular resolution and a typical noise level of 40mJy/beam, with reduced sensitivity near the field boundaries and bright sources. The catalogue consists of flux density and spectral index measurements for 14,110 sources, extracted from the mosaics, 1,247 of which are sub-components of complexes of sources.
265. 408MHz observations
- ID:
- ivo://CDS.VizieR/J/A+AS/120/89
- Title:
- 408MHz observations
- Short Name:
- J/A+AS/120/89
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- This is the second paper based on the 408MHz monitoring program with the East-West arm of the Bologna interferometer. The monitoring concerned 125 radio sources measured approximately once a month for 15 years. We present the summary of the variability analysis concerning all the sample and the monitoring data, not yet published, of the variable sources.
- ID:
- ivo://CDS.VizieR/J/A+A/656/A137
- Title:
- 144MHz radio fluxes of z>5 quasars
- Short Name:
- J/A+A/656/A137
- Date:
- 17 Mar 2022 14:39:39
- Publisher:
- CDS
- Description:
- Optically luminous quasars at z>5 are important probes of super-massive black hole (SMBH) formation. With new and future radio facilities, the discovery of the brightest low-frequency radio sources in this epoch would be an important new probe of cosmic reionization through 21-cm absorption experiments. We present the result of a study of the low-frequency radio properties of a sample of 115 known spectroscopically confirmed z>5 quasars using the second data release of the Low Frequency Array (LOFAR) Two Meter Sky survey (LoTSS-DR2), reaching noise levels of 80uJy/beam (at 144MHz) over an area of 5720 square degrees. We find that 41 sources (36%) are detected in LoTSS-DR2 at >2{sigma} significance and we explore the evolution of their radio properties (power, spectral index, and radio loudness) as a function of redshift and rest-frame ultra-violet properties.
- ID:
- ivo://CDS.VizieR/J/A+AS/97/435
- Title:
- 1410MHz-spectra of quasars III.
- Short Name:
- J/A+AS/97/435
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present the third and final part of the research at 1410MHz for 213 extragalactic objects from the Southern Hemisphere identified as Quasars by Veron-Cetty and Veron (1983A&AS...53..219V). The first (1988A&AS...76...21Q) and second (1990A&AS...83..393Q) parts contained measurement of the flux densities at 1410MHz for 473 sources.
- ID:
- ivo://CDS.VizieR/VIII/29A
- Title:
- 1400-MHz Survey of 1478 Abell Clusters of Galaxies
- Short Name:
- VIII/29A
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- This catalog contains observations of Abell clusters of galaxies which were obtained with the Green Bank 91-m telescope at 1400 MHz with an angular resolution of 10'x11' (RAxDEC). This catalog extends the sample of clusters originally published in Owen (1974AJ.....79..427O). The primary goals of this survey were to observe all Abell (1958ApJS....3..211A, Cat. VII/4) clusters with m10 (magnitude of the tenth brightest galaxy in the cluster) less than or equal to 17.0 and declinations north of -19 degrees, to observe all clusters with richness>=3 regardless of m10, and to obtain observations of a representative sample of the rest of the catalog (m10>=17.0; richness<=2). The abelclus.dat file contains ALL 957 detected sources (also beyond 0.5 corrected Abell radii). It contains 525 sources within 0.5 corrected Abell radii, while the published table1.dat file contains 487 entries corresponding to 485 distinct sources (in 442 clusters). The catalog entries contains the flux density at 1400 MHz, the Abell cluster number, richness class, distance class, m10, redshift estimate (z), corrected Abell cluster radius, right ascension (B1950), declination (B1950), deconvolved major and minor source axis lengths, position angle, and distance of the source from the cluster center.
- ID:
- ivo://CDS.VizieR/J/A+AS/41/151
- Title:
- 1415MHz Survey of Bright Galaxies
- Short Name:
- J/A+AS/41/151
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The radio continuum radiation at 1415MHz of 450 galaxies was observed with the Westerbork Synthesis Radio Telescope. 190 galaxies were detected. The survey provides data on the total intensity and on the structure of the radiation. The detection limit for point sources is 10mJy and the resolution is about 23" on average.
- ID:
- ivo://CDS.VizieR/J/ApJS/36/53
- Title:
- 2380 MHz survey of bright galaxies
- Short Name:
- J/ApJS/36/53
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- A 2380MHz survey of bright galaxies in the declination range from zero to +37{deg} has been made at Arecibo. It is complete to a photographic magnitude of +14.5mag in all right ascensions except between 11h 30min and 13h 00min, where the limit is +14.0mag. Four hundred fifty-six of the 2095 galaxies observed were detected above 15mJy, a cutoff which is the quadratic sum of 5 times the 2mJy rms confusion and 3 times the 3mJy receiver noise on a single scan.
