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- ID:
- ivo://CDS.VizieR/J/AZh/83/310
- Title:
- BV(RI)c photometry of S5 0716+714
- Short Name:
- J/AZh/83/310
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Photometric observations of the radio source S5 0716+71 were obtained in Johnson-Cousins BVRI filters from 1998 to 2001. with Zeiss-600 and Zeiss-1000 telescopes of SAO of the Russian Academy of Science.
- ID:
- ivo://CDS.VizieR/J/PAZh/44/383
- Title:
- Byurakan-IRAS galaxies (BIG) with SDSS spectra
- Short Name:
- J/PAZh/44/383
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The sample of Byurakan-IRAS galaxies (BIG) has been created based on optical identifications of IRAS Point Source Catalog (PSC) at high galactic latitudes. As a result, 1178 galaxies have been identified. 172 of them have been observed spectroscopically with Byurakan Astrophysical Observatory (BAO, Armenia) 2.6m, Special Astrophysical Observatory (SAO, Russia) 6m and Observatoire de Haute Provence (OHP, France) 1.93m telescopes. Later on, spectra were obtained for more 83 BIG objects in Sloan Digital Sky Survey (SDSS). We have extracted and studied these spectra, classified them and measured spectral features. Diagnostic diagrams have been built to distinguish starbursts (SB), LINERs and Seyfert galaxies. Cross-correlations were made for these objects with multiwavelength (MW) catalogues and their physical properties were studied. Among these 83 objects, 55 HII, 8 Seyfert galaxies, 2 LINERs, 4 other AGN, 6 composite spectrum objects, and 8 other emission-line galaxies have been revealed. Three of these objects are Ultra-Luminous InfraRed Galaxies (ULIRG).
- ID:
- ivo://CDS.VizieR/J/A+A/507/131
- Title:
- BzJK observations around radio galaxies
- Short Name:
- J/A+A/507/131
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We explore the environments of two radio galaxies at z~1.5, 7C 1751+6809 and 7C 1756+6520, using deep optical and near-infrared imaging. Our data cover 15x15arcmin^2^ fields around the radio galaxies. We develop and apply BzK color criteria to select cluster member candidates around the radio galaxies and find no evidence of an overdensity of red galaxies within 2Mpc of 7C 1751+6809. In contrast, 7C 1756+6520 shows a significant overdensity of red galaxies within 2Mpc of the radio galaxy, by a factor of 3.1+/-0.8 relative to the four MUSYC fields. At small separation (r<6"), this radio galaxy also has one z>1.4 evolved galaxy candidate, one z>1.4 star-forming galaxy candidate, and an AGN candidate (at indeterminate redshift).
- ID:
- ivo://CDS.VizieR/J/MNRAS/357/471
- Title:
- Calculated spectra for HeH^+^
- Short Name:
- J/MNRAS/357/471
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The wavelength and Einstein A coefficient are calculated for all rotation-vibration transitions of ^4^HeH^+^, ^3^HeH^+^, ^4^He^2^H^+^ and ^3^He^2^H^+^, giving a complete line list and the partition function for ^4^HeH^+^ and its isotopologues. This opacity is included in the calculation of the total opacity of low-metallicity stars and its effect is analysed for different conditions of temperature, density and hydrogen number fraction. For a low helium number fraction (as in the Sun), it is found that HeH^+^ has a visible but small effect for very low densities ({rho}<=10^-10^g/cm^3^), at temperatures around 3500K. However, for high helium number fraction, the effect of HeH^+^ becomes important for higher densities ({rho}<=10^-6^g/cm^3^), its effect being most important for a temperature around 3500K. Synthetic spectra for a variety of different conditions are presented.
- ID:
- ivo://CDS.VizieR/J/ApJ/533/744
- Title:
- Calibration of the Tully-Fischer relation
- Short Name:
- J/ApJ/533/744
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The correlation between the luminosities and rotation velocities of galaxies can be used to estimate distances to late-type galaxies. It is an appropriate moment to reevaluate this method given the great deal of new information available. The major improvements described here include: (1) the template relations can now be defined by large, complete samples, (3) the samples are drawn from a wide range of environments, (3) the relations are defined by photometric information at the B, R, I, and K' bands, (4) the multiband information clarifies problems associated with internal reddening, (5) the template zero points are defined by 24 galaxies with accurately known distances, and (6) the relations are applied to 12 clusters scattered across the sky and out to velocities of 8000km/s.
- ID:
- ivo://CDS.VizieR/J/AJ/153/157
- Title:
- Candidate ICRF flat-spectrum radio sources. III.
- Short Name:
- J/AJ/153/157
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- In extending our spectroscopic program, which targets sources drawn from the International Celestial Reference Frame (ICRF) Catalog, we have obtained spectra for ~160 compact, flat-spectrum radio sources and determined redshifts for 112 quasars and radio galaxies. A further 14 sources with featureless spectra have been classified as BL Lac objects. Spectra were obtained at three telescopes: the 3.58m European Southern Observatory New Technology Telescope, and the two 8.2m Gemini telescopes in Hawaii and Chile. While most of the sources are powerful quasars, a significant fraction of radio galaxies is also included from the list of non-defining ICRF radio sources.
- ID:
- ivo://CDS.VizieR/J/A+A/638/A29
- Title:
- 3C388 145, 392, 614, 1400 and 4850MHz images
- Short Name:
- J/A+A/638/A29
- Date:
- 23 Mar 2022 16:29:17
- Publisher:
- CDS
- Description:
- Restarted radio galaxies represent a unique tool to investigate the duty cycle of the jet activity in Active Galactic Nuclei. Due to a sharp discontinuity of the GHz spectral index distribution within its lobes, the radio galaxy 3C388 has for long being claimed to be a peculiar example of AGN with multi-epoch activity The goal of this work is to perform for the first time a spatially resolved study of the radio spectrum of this source down to MHz-frequencies, in order to investigate its radiative age and constrain its duty cycle. We have used new low frequency observations at 144MHz performed with the Low Frequency Array and at 350MHz performed with the Very Large Array combined with archival data at higher frequencies (614, 1400, 4850MHz). Results. We find that the spectral indices in the lower frequency range 144-614MHz have flatter values ({alpha}_low_~0.55-1.14) than those observed in the higher frequency range 1400-4850MHz ({alpha}_high_~0.75-1.57) but follow the same distribution across the lobes, with a systematic steepening towards the edges. However, the spectral shape throughout the source is not uniform and often deviates from standard models. This suggests that mixing of different particle populations is occurring, although it remains difficult to understand whether this is caused by observational limitations (insufficient spatial resolution and/or projection effects) or by the intrinsic presence of multiple particle populations, possibly related to the two different outbursts. By using single-injection radiative models we compute that the total source age is <~80Myr and that the duty cycle is about t_on_/t_tot_~60%, which is enough to prevent the intracluster medium from cooling according to X-ray estimates. While to date the radio spectral distribution of 3C388 remains a rare case among radio galaxies, multi-frequency surveys performed with new generation instruments will soon allow us to investigate whether more sources with the same characteristics do actually exist.
- ID:
- ivo://CDS.VizieR/J/MNRAS/496/2663
- Title:
- Canes Venatici I images with LOFAR
- Short Name:
- J/MNRAS/496/2663
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Dwarf galaxies are dark matter-dominated and therefore promising targets for the search for weakly interacting massive particles (WIMPs), which are well-known candidates for dark matter. Annihilation of WIMPs produce ultra-relativistic cosmic-ray electrons and positrons that emit synchrotron radiation in the presence of magnetic fields. For typical magnetic field strengths (few G) and O(GeV-TeV) WIMP masses (and thus typical electron energies of the same order) this emission peaks at hundreds of MHz. Here, we use the non-detection of 150-MHz radio continuum emission from the dwarf spheroidal galaxy 'Canes Venatici I' with the LOw-Frequency ARray (LO-FAR) to derive constraints on the annihilation cross section of WIMPs into primary electron-positron and other fundamental particle-antiparticle pairs. In this first-of-its-kind LOFAR study, we obtain new constraints on annihilating WIMP dark matter (DM). Using conservative estimates for the magnetic field strengths and diffusion coefficients, we obtain limits that are comparable with those by the Fermi Large Area Telescope (Fermi-LAT) using gamma-ray observations. Assuming s-wave annihilation and WIMPs making up 100% of the DM density, our limits exclude several thermal WIMP realisations in the [2, 20]-GeV mass range. A more ambitious multi-wavelength and multi-target LOFAR study could improve these limits by a few orders of magnitude.
- ID:
- ivo://CDS.VizieR/J/A+A/641/A22
- Title:
- CARLA J1103+3449 cluster datacube
- Short Name:
- J/A+A/641/A22
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Passive early-type galaxies dominate cluster cores at z<~1.5. At higher redshift, cluster core galaxies are observed to have on-going star-formation, which is fuelled by cold molecular gas.We measured the molecular gas reservoir of the central region around the radioloud active galactic nucleus (AGN) in the cluster CARLA J1103+3449 at z=1.44 using NOEMA. The AGN synchrotron emission dominates the continuum emission at 94.48GHz, and we measured its flux at the AGN position and at the position of two radio jets. Combining our measurements with published results over the range 4.71GHz-94.5GHz, and assuming S_synch_{prop.to}{nu}^-{alpha}^, we obtain a flat spectral index of = 0:14 0:03 for the AGN core emission, and a steeper index of {alpha}=1.43+/-0.04 and {alpha}=1.15+/-0.04 at positions close to the western and eastern lobes, respectively. The total spectral index is {alpha}=0.92+/-0.02 over the range 73.8MHz-94.5GHz.We detect two CO(2-1) emission lines, both blueshifted with respect to the AGN. Their emission corresponds to two regions, 17kpc southeast and 14kpc southwest of the AGN, not associated with galaxies. In these two regions, we find a total massive molecular gas reservoir of M^tot^_gas_=3.9+/-0.4x10^10^M_{sun}_, which dominates (>~60%) the central total molecular gas reservoir. These results can be explained by massive cool gas flows in the center of the cluster. The AGN early-type host is not yet quenched; its star formation rate is consistent with being on the main sequence of star-forming galaxies in the field (star formation rate ~30-140M_[sun}_/yr), and the cluster core molecular gas reservoir is expected to feed the AGN and the host star formation before quiescence. The other confirmed cluster members show star formation rates at 2 below the field main sequence at similar redshifts and do not have molecular gas masses larger than galaxies of similar stellar mass in the field.
