- ID:
- ivo://CDS.VizieR/J/other/Ap/48.304
- Title:
- BVRI of comparison stars in AGN fields
- Short Name:
- J/other/Ap/48.30
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Results are presented from CCD BVRI-observations of 145 comparison stars in the neighborhoods of 14 Seyfert galaxies, 3 quasars, and 5 BL Lac objects with right ascensions of 12 to 24 hours. The magnitudes of the observed stars ranged from V=11 to V=17. The typical photometric error for stars brighter V=14 is 0.01m. The B, V, Rc, and Ic magnitudes of most of these stars were not known previously. 14'x14' finding charts are provided. These results can be used for differential photometry of the nuclei of active galaxies in the B, V, Rc, and Ic bands.
Number of results to display per page
Search Results
- ID:
- ivo://CDS.VizieR/J/ApJ/664/761
- Title:
- BVRI photometry of AGNs in clusters
- Short Name:
- J/ApJ/664/761
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present a study of the distribution of AGNs in clusters of galaxies with a uniformly selected, spectroscopically complete sample of 35 AGNs in eight clusters of galaxies at z=0.06-->0.31. We find that the 12 AGNs with LX>10^42^ergs/s in cluster members more luminous than a rest-frame M_R_<-20mag are more centrally concentrated than typical cluster galaxies of this luminosity, although these AGNs have comparable velocity and substructure distributions to other cluster members.
- 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/542/A83
- Title:
- CAIXA. II. AGNs from excess variance analysis
- Short Name:
- J/A+A/542/A83
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We report on the results of the first XMM-Newton systematic "excess variance" study of all the radio quiet, X-ray unobscured AGN. The entire sample consist of 161 sources observed by XMM-Newton for more than 10ks in pointed observations, which is the largest sample used so far to study AGN X-ray variability on time scales less than a day. Recently it has been suggested that the same engine might be at work in the core of every Black Hole (BH) accreting object. In this hypothesis, the same variability should be observed in all AGN, once rescaled by the MBH (MBH) and accretion rate (dm/dt). We systematically compute the excess variance for all AGN, on different time-scales (10, 20, 40 and 80ks) and in different energy bands (0.3-0.7, 0.7-2 and 2-10keV).
- ID:
- ivo://CDS.VizieR/J/MNRAS/492/3073
- Title:
- CALIFA galaxies hosting an AGN
- Short Name:
- J/MNRAS/492/3073
- Date:
- 02 Feb 2022 07:33:25
- Publisher:
- CDS
- Description:
- We study the presence of optically-selected Active Galactic Nuclei (AGNs) within a sample of 867 galaxies extracted from the extended Calar-Alto Legacy Integral Field spectroscopy Area (eCALIFA) spanning all morphological classes. We identify 10 Type-I and 24 Type-II AGNs, amounting to ~4 per cent of our sample, similar to the fraction reported by previous explorations in the same redshift range. We compare the integrated properties of the ionized and molecular gas, and stellar population of AGN hosts and their non-active counterparts, combining them with morphological information. The AGN hosts are found in transitory parts (i.e. green-valley) in almost all analysed properties which present bimodal distributions (i.e. a region where reside star-forming galaxies and another with quiescent/retired ones). Regarding morphology, we find AGN hosts among the most massive galaxies, with enhanced central stellar-mass surface density in comparison to the average population at each morphological type. Moreover, their distribution peaks at the Sab-Sb classes and none are found among very late-type galaxies (>Scd). Finally, we inspect how the AGN could act in heir hosts regarding the quenching of star-formation. The main role of the AGN in the quenching process appears to be the removal (or heating) of molecular gas, rather than an additional suppression of the already observed decrease of the star-formation efficiency from late-to-early type galaxies.
- ID:
- ivo://CDS.VizieR/J/ApJ/823/95
- Title:
- CANDELS GOODS-S sources Chandra counterparts
- Short Name:
- J/ApJ/823/95
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Improving the capabilities of detecting faint X-ray sources is fundamental to increase the statistics on faint high-z AGN and star-forming galaxies. We performed a simultaneous Maximum Likelihood PSF fit in the [0.5-2]keV and [2-7]keV energy bands of the 4Ms Chandra Deep Field South (CDFS) data at the position of the 34930 CANDELS H-band selected galaxies. For each detected source we provide X-ray photometry and optical counterpart validation. We validated this technique by means of a raytracing simulation. We detected a total of 698 X-ray point-sources with a likelihood L>4.98 (i.e.> 2.7{sigma}). We show that the prior knowledge of a deep sample of Optical-NIR galaxies leads to a significant increase of the detection of faint (i.e. ~10^-17^cgs in the [0.5-2]keV band) sources with respect to "blind" X-ray detections. By including previous catalogs, this work increases the total number of X-ray sources detected in the 4Ms CDFS, CANDELS area to 793, which represents the largest sample of extremely faint X-ray sources assembled to date. Our results suggest that a large fraction of the optical counterparts of our X-ray sources determined by likelihood ratio actually coincides with the priors used for the source detection. Most of th e new detected sources are likely star-forming galaxies or faint absorbed AGN. We identified a few sources sources with putative photometric redshift z>4. Despite the low number statistics, this sample significantly increases the number of X-ray selected candidate high-z AGN.
- ID:
- ivo://CDS.VizieR/J/ApJ/793/101
- Title:
- CANDELS z~2 galaxy properties
- Short Name:
- J/ApJ/793/101
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We use CANDELS imaging, 3D-HST spectroscopy, and Chandra X-ray data to investigate if active galactic nuclei (AGNs) are preferentially fueled by violent disk instabilities funneling gas into galaxy centers at 1.3<z<2.4. We select galaxies undergoing gravitational instabilities using the number of clumps and degree of patchiness as proxies. The CANDELS visual classification system is used to identify 44 clumpy disk galaxies, along with mass-matched comparison samples of smooth and intermediate morphology galaxies. We note that despite being mass-matched and having similar star formation rates, the smoother galaxies tend to be smaller disks with more prominent bulges compared to the clumpy galaxies. The lack of smooth extended disks is probably a general feature of the z~2 galaxy population, and means we cannot directly compare with the clumpy and smooth extended disks observed at lower redshift. We find that z~2 clumpy galaxies have slightly enhanced AGN fractions selected by integrated line ratios (in the mass-excitation method), but the spatially resolved line ratios indicate this is likely due to extended phenomena rather than nuclear AGNs. Meanwhile, the X-ray data show that clumpy, smooth, and intermediate galaxies have nearly indistinguishable AGN fractions derived from both individual detections and stacked non-detections. The data demonstrate that AGN fueling modes at z~1.85 - whether violent disk instabilities or secular processes - are as efficient in smooth galaxies as they are in clumpy galaxies.
- ID:
- ivo://CDS.VizieR/J/A+A/461/823
- Title:
- Candidate Ly{alpha} emitting galaxies
- Short Name:
- J/A+A/461/823
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present the results of a large program conducted with the Very Large Telescope and augmented by observations with the Keck telescope to search for forming clusters of galaxies near powerful radio galaxies at 2.0<z<5.2. Besides MRC 1138-262 at z=2.16, the radio galaxy observed in our pilot program, we obtained narrow- and broad-band images of eight radio galaxies and their surroundings. The imaging was used to select candidate Ly{alpha} emitting galaxies in ~3x3Mpc^2^ areas near the radio galaxies. A total of 300 candidate emitters were found with a rest-frame Ly{alpha} equivalent width of EW0>15{AA} and significance Sigma{equiv.to}(EW0/DEW0)>3. Follow-up spectroscopy was performed on 152 candidates in seven of the radio galaxy fields. Of these, 139 were confirmed to be Ly{alpha} emitters, four were low redshift interlopers and nine were non-detections. With the adopted criteria the success rate is 139/152=91%. In addition, 14 objects with EW0<15 and/or Sigma<3 were confirmed to be Ly{alpha} emitters. Combined with the 15 Ly{alpha} emitters near MRC 1138-262, we have determined Ly{alpha} redshifts for 168 objects near eight radio galaxies.
- ID:
- ivo://CDS.VizieR/J/A+A/495/421
- Title:
- Catalog of AGN in XMM-Newton archive (CAIXA)
- Short Name:
- J/A+A/495/421
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present CAIXA, a Catalogue of AGN In the XMM-Newton Archive. It consists of all the radio-quiet X-ray unobscured (N_H_<2x10^22^cm^-2^) active galactic nuclei (AGN) observed by XMM-Newton in targeted observations, whose data are public as of March 2007. With its 156 sources, this is the largest catalogue of high signal-to-noise X-ray spectra of AGN. All the EPIC pn spectra of the sources in CAIXA were extracted homogeneously, and a baseline model was applied in order to derive their basic X-ray properties. These data are complemented by multiwavelength data found in the literature: black hole masses, full width half maximum (FWHM) of H{beta}, radio and optical fluxes.
- ID:
- ivo://CDS.VizieR/J/ApJ/640/603
- Title:
- Catalog of AGNs in the GOODS fields
- Short Name:
- J/ApJ/640/603
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present mid-infrared observations of active galactic nuclei (AGNs) in the GOODS fields, performed with the Spitzer Space Telescope. These are the deepest infrared and X-ray fields to date and cover a total area of 0.1{deg}^2^. AGNs are selected on the basis of their hard (28keV) X-ray emission.
