- ID:
- ivo://CDS.VizieR/J/A+A/567/A76
- Title:
- COSMOS field radio-loud AGN population at z>1
- Short Name:
- J/A+A/567/A76
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We select a sample of radio galaxies at high redshifts (z>1) in the COSMOS field by cross-matching optical and infrared (IR) images with the FIRST radio data. The aim of this study is to explore the high-z radio-loud (RL) active galactic nuclei (AGN) population at much lower luminosities than the classical samples of distant radio sources, which are similar to those of the local population of radio galaxies. Precisely, we extended a previous analysis focused on low-luminosity radio galaxies. The wide multiwavelength coverage provided by the COSMOS survey allows us to derive their spectral energy distributions (SEDs). We model them with our own developed technique 2SPD that includes old and young stellar populations and dust emission. When added to those previously selected, we obtain a sample of 74 RL AGN. The SED modeling returns several important quantities associated with the AGN and host properties. The resulting photometric redshifts range from z~0.7 to 3. The sample mostly includes compact radio sources but also 21 FR IIs sources; the radio power distribution of the sample covers ~10^31.5^-10^34.3^erg/s/Hz, thus straddling the local FR I/FR II break. The inferred range of stellar mass of the hosts is ~10^10^-10^11.5^M_{sun}_. The SEDs are dominated by the contribution from an old stellar population with an age of ~1-3Gyr for most of the sources. However, UV and mid-IR (MIR) excesses are observed for half of the sample. The dust luminosities inferred from the MIR excesses are in the range, L_dust_~10^43^-10^45.5^erg/s, which are associated with temperatures approximately of 350-1200K. Estimates of the UV component yield values of ~10^41.5^-10^45.5^erg/s at 2000{AA}. The UV emission is significantly correlated with both IR and radio luminosities; the former being the stronger link. However, the origin of UV and dust emission, whether it is produced by the AGN of by star formation, is still unclear. Our results show that this RLAGN population at high redshifts displays a wide variety of properties. Low-power radio galaxies, which are associated with UV- and IR-faint hosts are generally similar to red massive galaxies of the local FR Is. At the opposite side of the radio luminosity distribution, large MIR and UV excesses are observed in objects consistent with quasar-like AGN, as also proved by their high dust temperatures, which are more similar to local FR IIs.
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Search Results
- ID:
- ivo://CDS.VizieR/J/A+AS/115/439
- Title:
- CO survey of galaxies
- Short Name:
- J/A+AS/115/439
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- A large survey of galaxies in the J=1-0 CO line, performed during 1985-1988 using the 15-m SEST and the 20-m millimetre wave telescope of Onsala Space Observatory, is presented. The HPBW of the telescopes are 44" and 33" at 115GHz, respectively. The central positions of 168 galaxies were observed and 101 of these were detected in the CO line. More than 20% of these are new detections. Maps of some of the galaxies are also presented.
- ID:
- ivo://CDS.VizieR/J/A+AS/116/193
- Title:
- CO survey of spirals in Coma supercluster
- Short Name:
- J/A+AS/116/193
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present observations of the ^12^CO(J=1-0) line at 2.6mm of 65 galaxies located in the Coma supercluster region: 33 actually belong to the Coma supercluster while 32 are either foreground or background objects. These data have been obtained using the NRAO 12m telescope at Kitt Peak (United States), and for four galaxies, using the IRAM 30m telescope at Pico Veleta (Spain). Out of these 65 galaxies, 54 had never been observed in the CO(1-0) line; 49 have been detected by us, of which 37 are new detections. We give molecular gas masses deduced from the CO line integrated intensities, and upper limits for the 16 undetected objects, computed with a Galactic conversion factor N(H_2_)=2.3x10^20^I(CO) and H_0_=75km/s/Mpc.
- ID:
- ivo://CDS.VizieR/J/ApJS/235/34
- Title:
- Deep JVLA imaging of GOODS-N at 20cm
- Short Name:
- J/ApJS/235/34
- Date:
- 08 Mar 2022 13:27:20
- Publisher:
- CDS
- Description:
- New wideband continuum observations in the 1-2GHz band of the GOODS-N field using NSF's Karl G. Jansky Very Large Array (VLA) are presented. The best image with an effective frequency of 1525MHz reaches an rms noise in the field center of 2.2{mu}Jy, with 1.6" resolution. A catalog of 795 sources is presented covering a radius of 9 arcminutes centered near the nominal center for the GOODS-N field, very near the nominal VLA pointing center for the observations. Optical/NIR identifications and redshift estimates both from ground-based and HST observations are discussed. Using these optical/NIR data, it is most likely that fewer than 2% of the sources without confusion problems do not have a correct identification. A large subset of the detected sources have radio sizes >1". It is shown that the radio orientations for such sources correlate well with the HST source orientations, especially for z<1. This suggests that a least a large subset of the 10kpc-scale disks of luminous infrared/ultraluminous infrared galaxies (LIRG/ULIRG) have strong star formation, not just in the nucleus. For the half of the objects with z>1, the sample must be some mixture of very high star formation rates, typically 300M_{sun}_/yr, assuming pure star formation, and an active galactic nucleus (AGN) or a mixed AGN/star formation population.
- ID:
- ivo://CDS.VizieR/J/MNRAS/462/3386
- Title:
- Deep NIR catalogue of HIZOA galaxies
- Short Name:
- J/MNRAS/462/3386
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present a deep near-infrared (NIR; J, H, and K_s_ bands) photometric catalogue of sources from the Parkes HI Zone of Avoidance (HIZOA) survey, which forms the basis for an investigation of the matter distribution in the Zone of Avoidance. Observations were conducted between 2006 and 2013 using the Infrared Survey Facility (IRSF), a 1.4-m telescope situated at the South African Astronomical Observatory site in Sutherland. The images cover all 1108 HIZOA detections and yield 915 galaxies. An additional 105 bright 2MASS galaxies in the southern ZOA were imaged with the IRSF, resulting in 129 galaxies. The average K_s_-band seeing and sky background for the survey are 1.38-arcsec and 20.1mag, respectively. The detection rate as a function of stellar density and dust extinction is found to depend mainly on the HI mass of the HI detected galaxies, which in principal correlates with the NIR brightness of the spiral galaxies. The measured isophotal magnitudes are of sufficient accuracy (errors ~0.02mag) to be used in a Tully-Fisher analysis. In the final NIR catalogue, 285 galaxies have both IRSF and 2MASS photometry (180 HIZOA plus 105 bright 2MASX galaxies). The K_s_-band isophotal magnitudes presented in this paper agree, within the uncertainties, with those reported in the 2MASX catalogue. Another 30 galaxies, from the HIZOA northern extension, are also covered by UKIDSS Galactic Plane Survey (GPS) images, which are one magnitude deeper than our IRSF images. A modified version of our photometry pipeline was used to derive the photometric parameters of these UKIDSS galaxies. Good agreement was found between the respective K_s_-band isophotal magnitudes. These comparisons confirm the robustness of the isophotal parameters and demonstrate that the IRSF images do not suffer from foreground contamination, after star removal, nor underestimate the isophotal fluxes of ZoA galaxies.
- ID:
- ivo://CDS.VizieR/J/ApJS/119/159
- Title:
- Deep survey of HI-selected galaxies
- Short Name:
- J/ApJS/119/159
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- In a 21cm neutral hydrogen survey of approximately 55{deg}^2^ out to a redshift of cz=8340km/s, we have identified 75 extragalactic HI sources. These objects comprise a well-defined sample of extragalactic sources chosen by means that are independent of optical surface brightness selection effects. In this paper we describe the Arecibo survey procedures and HI data, follow-up VLA HI observations made of several unusual sources, and Kitt Peak B-, R-, and I-band photometry for nearly all of the galaxies. We have also gathered information for some of the optically detected galaxies within the same search volume.
- ID:
- ivo://CDS.VizieR/J/MNRAS/350/1485
- Title:
- 2dFGRS: Radio galaxies properties
- Short Name:
- J/MNRAS/350/1485
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The clustering properties of local, S_1.4GHz_>=1mJy, radio sources are investigated for a sample of 820 objects drawn from the joint use of the Faint Images of the Radio Sky at 20cm (FIRST, <VIII/71>) and 2dF Galaxy Redshift surveys (<VII/223>, <VII/226>). To this aim, we present 271 new b_J_<=19.45mag spectroscopic counterparts of FIRST radio sources to be added to those already introduced in our previous paper.
- ID:
- ivo://CDS.VizieR/J/ApJ/677/1
- Title:
- Dimensionless coordinate distances
- Short Name:
- J/ApJ/677/1
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We extend and apply a model-independent analysis method developed earlier by Daly & Djorgovski (2003ApJ...597....9D and 2004, Cat. <J/ApJ/612/652>) to new supernova, radio galaxy, and galaxy cluster samples to study the acceleration history of the universe and the properties of the dark energy. There is good agreement between results obtained with radio galaxies and supernovae, suggesting that both distance indicators are reliable. The deceleration parameter q(z) is obtained assuming only the validity of the FRW metric, allowing for a range of values of space curvature, and independent of a gravity theory and the physical nature of the contents of the universe. We show that q_0_ is independent of space curvature, and obtain q_0_=-0.48+/-0.11. The transition redshift when q_0_=0 is z_T_=0.78^+0.08^_-0.27_ for zero space curvature, and has a weak dependence on space curvature. We find good agreement between model-independent quantities and those predicted by general relativity, indicating that GR provides a good description of the data over look-back times of ten billion years.
- ID:
- ivo://CDS.VizieR/J/ApJ/612/652
- Title:
- Dimensionless coordinate distances to supernovae
- Short Name:
- J/ApJ/612/652
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Understanding the nature of dark energy, which appears to drive the expansion of the universe, is one of the central problems of physical cosmology today. In an earlier paper (Daly & Djorgovski, 2003ApJ...597....9D) we proposed a novel method to determine the expansion rate E(z) and the deceleration parameter q(z) in a largely model-independent way, directly from the data on coordinate distances y(z). Here we expand this methodology to include measurements of the pressure of dark energy p(z), its normalized energy density fraction f(z), and the equation-of-state parameter w(z). We then apply this methodology to a new, combined data set of distances to supernovae and radio galaxies.
- ID:
- ivo://CDS.VizieR/J/MNRAS/394/2197
- Title:
- Distant radio galaxies in southern hemisphere
- Short Name:
- J/MNRAS/394/2197
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We have compiled a sample of 234 ultra-steep-spectrum (USS) selected radio sources in order to find high-redshift radio galaxies. The sample covers the declination range -40{deg}<{delta}<-30{deg} in the overlap region between the 1400-MHz National Radio Astronomy Observatory (NRAO) Very Large Array (VLA) Sky Survey (NVSS), 408-MHz Revised Molonglo Reference Catalogue and the 843-MHz Sydney University Molonglo Sky Survey (the MRCR-SUMSS sample). This is the second in a series of papers on the MRCR-SUMSS sample, and here we present the K-band (2.2{mu}m) imaging of 173 of the sources primarily from the Magellan and the Anglo-Australian Telescopes. We detect a counterpart to the radio source in 93 per cent of the new K-band images which, along with previously published data, makes this the largest published sample of K-band counterparts to USS-selected radio galaxies. The location of the K-band identification has been compared to the features of the radio emission for the double sources. We find that the identification is most likely to lie near the mid-point of the radio lobes rather than closer to the brighter lobe, making the centroid a less likely place to find the optical counterpart. 79 per cent of the identifications are less than 1arcsec from the radio lobe axis. These results differ from studies of low-redshift radio samples where the environments are typically not nearly so dense and disturbed as those at high redshift. In contrast to some literature samples, we find that the majority of our sample shows no alignment between the near-infrared and radio axes. Several different morphologies of aligned structures are found and those that are aligned within 10{deg} are consistent with jet-induced star formation. The distribution and median value of the K-band magnitudes for the MRCR-SUMSS sample are found to be similar to several other USS-selected samples even though each sample has a very different median 1400MHz flux density. USS selection from a lower radio-frequency sample has not netted fainter K-band magnitudes, which may imply that the k-correction is not responsible for the effectiveness of USS selection.
