- ID:
- ivo://CDS.VizieR/J/ApJS/167/103
- Title:
- Radio/Optical catalog of the SSA 13 field
- Short Name:
- J/ApJS/167/103
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present a 1.4GHz catalog of 810 radio sources (560 sources in the complete sample) found in the SSA 13 field (RA=13:12, DE=42:38). The 1.4GHz radio image was obtained from a 91hr VLA integration with an rms noise level of 4.82uJy/beam at the field center. Optical images in the R band (6300{AA}) and z band (9200{AA}) with 3{sigma} detection magnitudes of 26.1 and 24.9, respectively, were obtained from three observing nights on the 8m Subaru Telescope. We find that 88%+/-2% of the radio sources are identified with an optical counterpart.
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- ID:
- ivo://CDS.VizieR/J/ApJ/900/125
- Title:
- Radio properties of Swift/BAT AGNs
- Short Name:
- J/ApJ/900/125
- Date:
- 02 Feb 2022 09:04:43
- Publisher:
- CDS
- Description:
- We address the very large diversity of jet production efficiency in active galactic nuclei (AGNs) by using data on low-redshift AGNs selected from the Swift/BAT catalog and having black hole (BH) masses larger than 10^8.5^M_{sun}_. Most of these AGNs accrete at intermediate rates and have bolometric luminosities dominated by mid-IR radiation. Our sample contains 14% radio-loud (RL), 6% radio-intermediate, and 80% radio-quiet (RQ) AGNs. All RL objects are found to have extended radio structures, and most of them have classical FR II morphology. Converting their radio loudness to jet production efficiency, we find that the median of this efficiency is on the order of ({epsilon}_d_/0.1)%, where {epsilon}_d_=L_bol_/(dM/dt)c^2^ is the radiation efficiency of the accretion disk. Without knowing the contribution of jets to the radio emission in RQ AGNs, we are only able to estimate their efficiencies using upper limits. Their median is found to be 0.002({epsilon}_d_/0.1)%. Our results suggest that some threshold conditions must be satisfied to allow the production of strong, relativistic jets in RL AGNs. We discuss several possible scenarios and argue that the production of collimated, relativistic jets must involve the Blandford-Znajek mechanism and can be activated only in those AGNs whose lifetime is longer than the time required to enter the magnetically arrested disk (MAD). Presuming that MAD is required to collimate relativistic jets, we expect that the weak nonrelativistic jets observed in some RQ AGNs are produced by accretion disks rather than by rotating BHs.
- ID:
- ivo://CDS.VizieR/J/AJ/137/3869
- Title:
- Radio SNRs in 4 irregular galaxies
- Short Name:
- J/AJ/137/3869
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We survey four nearby irregular galaxies for radio supernova remnants (SNRs) using deep (1{sigma}~20uJy), high-resolution (~20pc) Very Large Array continuum data at 20, 6, and 3.6cm. We identify discrete sources in these galaxies and use radio spectral indices and H{alpha} images to categorize them as SNRs, HII regions, or background radio galaxies. Our classifications are generally in good agreement with the literature. We identify a total of 43 SNR candidates: 23 in NGC 1569, seven in NGC 4214, five in NGC 2366, and eight in NGC 4449. Only one SNR - the well-studied object J1228+441 in NGC 4449 - is more luminous at 20cm than Cas A. By comparing the total thermal flux density in each galaxy with that localized in HII regions, we conclude that a significant fraction must be in a diffuse component or in low-luminosity HII regions.
- ID:
- ivo://CDS.VizieR/VIII/43
- Title:
- Radio survey of clusters of galaxies
- Short Name:
- VIII/43
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Observations of Abell clusters at 11.1, 6.2, 6.3 and 2.8cm with the 100m Effelsberg telescope. The data were compiled by H.J. Andernach.
- ID:
- ivo://CDS.VizieR/J/other/BSAO/40.5
- Title:
- RATAN-600 RC radio sources
- Short Name:
- J/other/BSAO/40.
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We use the RATAN-600 radio telescope for picking up the most distant objects in the Universe. As a first step, about 100 steep spectrum FRII radio galaxies (SS FRII RG) from the RATAN-600 RC catalog (Parijskij et al., 1991, Cat. <J/A+AS/87/1>; 1992A&AS...96..583P) were mapped by the VLA and identified with optical objects down to 24-25 R mag. All the VLA images and all the deep CCD images of the RC SS fields, collected up to now, are given. An updated list of calibrators with the known redshifts of the same SS FRII class RGs was compiled to estimate photometric redshifts, redshifts from angular size - redshift relations and by the radio "standard candle" method. The mean redshift of the RC SS FRII RG list happened to be greater than 2. BVRI photometry was made, and by standard model fittings we estimated "color" redshifts and the ages of stellar systems of the parent gE galaxies in 14 cases. Several objects were found in which active star formation began in the first billion years after the Big Bang. We believe that more than 10000 of such old active galaxies are available on the sky and all of them are in the range of present day optical and radio facilities.
- ID:
- ivo://CDS.VizieR/J/A+A/616/L10
- Title:
- RCW120 fragmentation at 0.01pc scale
- Short Name:
- J/A+A/616/L10
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Little is known about how high-mass stars form. Around 30% of the young high-mass stars in the Galaxy are observed at the edges of ionized (HII) regions. Therefore these are places of choice to study the earliest stages of high-mass star formation, especially towards the most massive condensations. High-spatial resolution observations in the millimeter range might reveal how these stars form and how they assemble their mass. We want to study the fragmentation process down to the 0.01pc scale in the most massive condensation (1700M_{sun}_) observed at the south-western edge of the HII region RCW 120 where the most massive Herschel cores (~124M_{sun}_ in average) could form high-mass stars. Using ALMA 3mm continuum observations towards the densest and most massive millimetric condensation (Condensation 1) of RCW 120, we used the getimages and getsources algorithms to extract the sources detected with ALMA and obtained their physical parameters. The fragmentation of the Herschel cores is discussed through their Jeans mass to understand the properties of the future stars. We extracted 18 fragments from the ALMA continuum observation at 3mm towards 8 cores detected with Herschel, whose mass and deconvolved size range from 2M_{sun}_ to 32M_{sun}_ and from 1.6mpc to 28.8mpc, respectively. The low degree of fragmentation observed, regarding to the thermal Jeans fragmentation, suggests that the observed fragmentation is inconsistent with ideal gravitational fragmentation and other ingredients such as turbulence or magnetic fields should be added in order to explain it. Finally, the range of fragments' mass indicates that the densest condensation of RCW 120 is a favourable place for the formation of high-mass stars with the presence of a probable UCHII region associated with the 27M_{sun}_ Fragment 1 of Core 2.
- ID:
- ivo://CDS.VizieR/J/MNRAS/442/533
- Title:
- Recently quenched elliptical galaxies in SDSS
- Short Name:
- J/MNRAS/442/533
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We use the Sloan Digital Sky Survey to investigate the properties of massive elliptical galaxies in the local Universe (z<=0.08) that have unusually blue optical colours. Through careful inspection, we distinguish elliptical from non-elliptical morphologies among a large sample of similarly blue galaxies with high central light concentrations (c_r_>=2.6). These blue ellipticals comprise 3.7 per cent of all c_r>=2.6 galaxies with stellar masses between 10^10^ and 10^11^h^-2^M_{sun}_. Using published fibre spectrum diagnostics, we identify a unique subset of 172 non-star-forming ellipticals with distinctly blue urz colours and young (<3Gyr) light-weighted stellar ages. These recently quenched ellipticals (RQEs) have a number density of 2.7-4.7x10^-5^h^3^/Mpc^3^ and sufficient numbers above 2.5x10^10^h^-2^M_{sun}_ to account for more than half of the expected quiescent growth at late cosmic time assuming that this phase lasts 0.5Gyr. RQEs have properties that are consistent with a recent merger origin (i.e. they are strong 'first-generation' elliptical candidates), yet few involved a starburst strong enough to produce an E+A signature. The preferred environment of RQEs (90 per cent reside at the centres of <3x10^12^h^-1^M_{sun}_ groups) agrees well with the 'small group scale' predicted for maximally efficient spiral merging on to their halo centre and rules out satellite-specific quenching processes. The high incidence of Seyfert and LINER activity in RQEs and their plausible descendants may heat the atmospheres of small host haloes sufficiently to maintain quenching.
- ID:
- ivo://CDS.VizieR/J/MNRAS/456/3899
- Title:
- Red galaxies with pseudo-bulges in the SDSS
- Short Name:
- J/MNRAS/456/3899
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Pseudo-bulges are expected to markedly differ from classical quasi-monolithically forming bulges in their star formation history (SFH) and chemical abundance patterns. To test this simple expectation, we carry out a comparative structural and spectral synthesis analysis of 10^6^ red massive galaxies issued from the Sloan Digital Sky Survey (SDSS), sub-divided into bulgeless, pseudo-bulge and classical bulge galaxies according to their photometric characteristics, and further obeying a specific selection to minimize uncertainties in the analysis and ensure an unbiased derivation and comparison of SFHs. Our 2D photometry analysis suggests that discs underlying pseudo-bulges typically have larger exponential scalelengths than bulgeless galaxies, despite similar integral disc luminosities. Spectral synthesis models of the stellar emission within the 3-arcsec SDSS fibre aperture reveal a clear segregation of bulgeless and pseudo-bulge galaxies from classical bulges on the luminosity-weighted planes of age-metallicity and mass-metallicity, though a large dispersion is observed within the two former classes. The secular growth of pseudo-bulges is also reflected upon their cumulative stellar mass as a function of time, which is shallower than that for classical bulges. Such results suggest that the centres of bulgeless and pseudo-bulge galaxies substantially differ from those of bulgy galaxies with respect to their SFH and chemical enrichment history, which likely points to different formation/assembly mechanisms.
- ID:
- ivo://CDS.VizieR/J/ApJS/157/1
- Title:
- Red-Sequence Cluster Survey
- Short Name:
- J/ApJS/157/1
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The Red-Sequence Cluster Survey (RCS) is a ~100{deg}^2^, two-filter imaging survey in the R_C_ and z' filters, designed primarily to locate and characterize galaxy clusters to redshifts as high as z=1.4. This paper provides a detailed description of the survey strategy and execution, including a thorough discussion of the photometric and astrometric calibration of the survey data. These catalogs, representing about 10% of the total survey and comprising a total of 429 candidate clusters and groups, contain a total of 67 cluster candidates at a photometric redshift of 0.9<z<1.4, down to the chosen significance threshold of 3.29{sigma}.
- ID:
- ivo://CDS.VizieR/J/A+A/391/887
- Title:
- Redshifts in the Hydra/Antlia Extension
- Short Name:
- J/A+A/391/887
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- As part of our program to map the large-scale distribution of galaxies behind the Milky Way, we used the Parkes 210 ft (64m) radio telescope for pointed HI observations of a sample of low surface-brightness (due to heavy obscuration) spiral galaxies selected from the deep optical Zone of Avoidance (ZOA) galaxy catalog in the Hydra/Antlia region (Kraan-Korteweg, 2000, Cat. <J/A+AS/141/123>). Searching a simultaneous velocity range of either 300 to 5500km/s or 300 to 10500km/s to an rms level of typically 2-4mJy resulted in detections in 61 of the 139 pointings, leading to a total of 66 detections (an additional detection was made in a reference position, and two other pointings revealed two and four independent signals respectively). Except for 2 strong HI emitters identified in the shallow Zone of Avoidance HI survey (Henning et al., 2000AJ....119.2686H), all HI detections are new.
