- ID:
- ivo://CDS.VizieR/J/A+A/659/A32
- Title:
- Turin-SyCAT, Seyferts multifrequency catalog
- Short Name:
- J/A+A/659/A32
- Date:
- 02 Mar 2022 06:48:51
- Publisher:
- CDS
- Description:
- We present the first release of Turin-SyCAT, a multifrequency catalog of Seyfert galaxies. We selected Seyfert galaxies considering criteria based on radio, infrared, and optical properties and starting from sources belonging to hard X-ray catalogs and surveys. We visually inspected optical spectra available for all selected sources. We adopted homogeneous and stringent criteria in the source selection aiming at reducing the possible contamination from other source classes. Our final catalog includes 351 Seyfert galaxies distinguished in 233 type 1 and 118 type 2. Type 1 Seyfert galaxies appear to have mid-IR colors similar to blazars, but are distinguished from them by their radio-loudness. Additionally, Seyfert 2 galaxies have mid-IR colors more similar to quasars than BL Lac objects. As expected from their spectral properties, type 1 and 2 Seyfert galaxies show a clear distinction when using the u-r color. Finally, we found a tight correlation between the mid-IR fluxes at both 12 and 22 um (i.e., F12 and F22, respectively) and hard X-ray fluxes between 15 and 150 keV. Both Seyfert types appear to follow the same trend and share similar values of the ratios of F12 and F22 to FHX in agreement with expectations of the AGN unification scenario. As future perspectives, the Turin-SyCAT will then be used to search for heavily obscured Seyfert galaxies among unidentified hard X-ray sources, given the correlation between mid-IR and hard X-rays, and to investigate their large-scale environments.
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Search Results
- ID:
- ivo://CDS.VizieR/J/A+A/589/A94
- Title:
- TU UMa light curves and maxima, CL Aur minima
- Short Name:
- J/A+A/589/A94
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Recent statistical studies prove that the percentage of RR Lyrae pulsators that are located in binaries or multiple stellar systems is considerably lower than might be expected. This can be better understood from an in-depth analysis of individual candidates. We investigate in detail the light time effect of the most probable binary candidate TU UMa. This is complicated because the pulsation period shows secular variation. We model possible light time effect of TU UMa using a new code applied on previously available and newly determined maxima timings to confirm binarity and refine parameters of the orbit of the RRab component in the binary system. The binary hypothesis is also tested using radial velocity measurements. We used new approach to determine brightness maxima timings based on template fitting. This can also be used on sparse or scattered data. This approach was successfully applied on measurements from different sources. To determine the orbital parameters of the double star TU UMa, we developed a new code to analyse light time effect that also includes secular variation in the pulsation period. Its usability was successfully tested on CL Aur, an eclipsing binary with mass-transfer in a triple system that shows similar changes in the O-C diagram. Since orbital motion would cause systematic shifts in mean radial velocities (dominated by pulsations), we computed and compared our model with centre-of-mass velocities. They were determined using high-quality templates of radial velocity curves of RRab stars. Maxima timings adopted from the GEOS database (168) together with those newly determined from sky surveys and new measurements (85) were used to construct an O-C diagram spanning almost five proposed orbital cycles. This data set is three times larger than data sets used by previous authors. Modelling of the O-C dependence resulted in 23.3-year orbital period, which translates into a minimum mass of the second component of about 0.33Ms. Secular changes in the pulsation period of TU UMa over the whole O-C diagram were satisfactorily approximated by a parabolic trend with a rate of -2.2ms/yr. To confirm binarity, we used radial velocity measurements from nine independent sources. Although our results are convincing, additional long-term monitoring is necessary to unambiguously confirm the binarity of TU UMa.
6983. TV Boo V light curve
- ID:
- ivo://CDS.VizieR/J/MNRAS/428/1442
- Title:
- TV Boo V light curve
- Short Name:
- J/MNRAS/428/1442
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- This study investigates periodic modulation of the light curve of the RRc star TV Boo and its physical parameters based on photometric data. This phenomenon, known as the Blazhko effect, is quite rare among RRc stars. The frequency analysis based on the data gathered at the Masaryk University Observatory (MUO) and also using SuperWASP data revealed symmetrically structured peaks around the main pulsation frequency and its harmonics, which indicate two modulation components of the Blazhko period. The main modulation periodicity was found to be 9.7374+/-0.0054d. This is one of the shortest known Blazhko periods among RRc stars. The second modulation period (21.5+/-0.2d) causes changes of the Blazhko effect itself. Some indices show that TV Boo could be affected by long-term changes of the order of years. Basic physical parameters were estimated via an MUO V light-curve solution using Fourier parameters. TV Boo seems to be a low-metallicity star with [Fe/H]=-1.89.
- ID:
- ivo://CDS.VizieR/II/108
- Title:
- Two-Micron Sky Survey, Nearest SAO Stars on POSS
- Short Name:
- II/108
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- This catalog is a list of potential guide stars developed for a program to obtain more precise positions of objects in the IRC Two-Micron Sky Survey of Neguebauer and Leighton (1969). For each IRC source (col. 1), it gives: (col. 2) the identification of the star in the SAO catalog which is nearest, (col. 3) the great circle arc distance (in seconds) between the SAO star and the IRC source, (col. 4) the position angle (in degrees) of the IRC source relative to the SAO star, (col. 5) the plate number(s) of the POSS on which the IRC source appears, (col. 6,7) the approximate rectangular coordinates (in mm) of the IRC source on the POSS print area with respect to the Southwest corner, and (col. 8) the modified Luyten Palomar number. The POSS plate numbers given are for the red plates.
- ID:
- ivo://CDS.VizieR/II/2B
- Title:
- Two-Micron Sky Survey (TMSS)
- Short Name:
- II/2B
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The catalog, giving sources of emission in the 2.2-micrometer region for more than 5000 stars, represents a systematic survey of the Northern Hemisphere for stars brighter than third magnitude. The survey was carried out with a telescope at Mount Wilson, California, having a 62-inch diameter and an f/l aluminized epoxy mirror mounted equatorially. Radiation at an effective wavelength of 2.2 micrometers was detected by a lead sulfide photoconductive cell cooled by liquid nitrogen. In addition to the 2.2-micrometer detector array, radiation at an effective wavelength of 0.84 micrometers was detected by a simple silicon photovoltaic cell. The catalog includes right ascension and declination (B1950.0), K and I magnitudes, number of measurements, V magnitude, spectral types, cross identifications to the numbering systems of the General Catalogue, the Durchmusterung catalogs, the Bright Star Catalogue, and star names.
- ID:
- ivo://CDS.VizieR/J/other/PZ/31.3
- Title:
- Two new cataclysmic variables in Lyra
- Short Name:
- J/other/PZ/31.3
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- I report on the discovery of two cataclysmic variables in the same field in Lyra, originally identified on the base of their magnitudes in the USNO-B1.0 catalog and on Palomar images. The historical light curves were analyzed from 300+ photographic plates of the Moscow collection, covering 35 years of observations. One of the two stars, USNO-B1.0 1320-0390658, is showing rather frequent outbursts from B~20 to B=15.2 and is likely a dwarf nova of the UGSS subtype. The other variable, USNO-B1.0 1321-0397655, with only one observed outburst in 1993, from B~19 to I=11.8, is either an UGWZ dwarf nova or a recurrent nova. In both cases, its next outburst can occur in the nearest future.
- ID:
- ivo://CDS.VizieR/J/ApJS/242/4
- Title:
- Two new catalogs of blazar candidates
- Short Name:
- J/ApJS/242/4
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present two catalogs of radio-loud candidate blazars whose Wide-Field Infrared Survey Explorer (WISE) mid-infrared colors are selected to be consistent with the colors of confirmed {gamma}-ray-emitting blazars. The first catalog is the improved and expanded release of the WISE Blazar-like Radio-Loud Sources (WIBRaLS) catalog presented by D'Abrusco et al. It includes sources detected in all four WISE filters, spatially cross-matched with radio sources in one of three radio surveys and radio-loud based on their q_22_ spectral parameter. WIBRaLS2 includes 9541 sources classified as BL Lacs, flat-spectrum radio quasars, or mixed candidates based on their WISE colors. The second catalog, called KDEBLLACS, based on a new selection technique, contains 5579 candidate BL Lacs extracted from the population of WISE sources detected in the first three WISE passbands ([3.4], [4.6], and [12]) only, whose mid-infrared colors are similar to those of confirmed, {gamma}-ray BL Lacs. Members of KDBLLACS are also required to have a radio counterpart and be radio-loud based on the parameter q_12_, defined similarly to the q_22_ used for the WIBRaLS2. We describe the properties of these catalogs and compare them with the largest samples of confirmed and candidate blazars in the literature. We cross-match the two new catalogs with the most recent catalogs of {gamma}-ray sources detected by the Fermi Large Area Telescope. Since spectroscopic observations of candidate blazars from the first WIBRaLS catalog within the uncertainty regions of {gamma}-ray unassociated sources confirmed that ~90% of these candidates are blazars, we anticipate that these new catalogs will again play an important role in the identification of the {gamma}-ray sky.
- ID:
- ivo://CDS.VizieR/J/ApJ/727/125
- Title:
- Two secondary eclipses of WASP-12b with Spitzer
- Short Name:
- J/ApJ/727/125
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We observed two secondary eclipses of the exoplanet WASP-12b using the Infrared Array Camera on the Spitzer Space Telescope. The close proximity of WASP-12b to its G-type star results in extreme tidal forces capable of inducing apsidal precession with a period as short as a few decades. This precession would be measurable if the orbit had a significant eccentricity, leading to an estimate of the tidal Love number and an assessment of the degree of central concentration in the planetary interior. An initial ground-based secondary-eclipse phase reported by Lopez-Morales et al. (0.510+/-0.002; 2010ApJ...716L..36L) implied eccentricity at the 4.5{sigma} level. The spectroscopic orbit of Hebb et al. (2009ApJ...693.1920H) has eccentricity 0.049+/-0.015, a 3{sigma} result, implying an eclipse phase of 0.509+/-0.007. However, there is a well-documented tendency of spectroscopic data to overestimate small eccentricities. Our eclipse phases are 0.5010+/-0.0006 (3.6 and 5.8um) and 0.5006+/-0.0007 (4.5 and 8.0um). An unlikely orbital precession scenario invoking an alignment of the orbit during the Spitzer observations could have explained this apparent discrepancy, but the final eclipse phase of Lopez-Morales et al. (0.510^+0.007^_-0.006_) is consistent with a circular orbit at better than 2{sigma}. An orbit fit to all the available transit, eclipse, and radial-velocity data indicates precession at <1{sigma}; a non-precessing solution fits better. We also comment on analysis and reporting for Spitzer exoplanet data in light of recent re-analyses.
- ID:
- ivo://CDS.VizieR/J/AJ/137/3826
- Title:
- Two transits of the giant planet WASP-4b
- Short Name:
- J/AJ/137/3826
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present photometry of two transits of the giant planet WASP-4b with a photometric precision of 400-800 parts per million and a time sampling of 25-40s. The two midtransit times are determined to within 6s. Together with previously published times, the data are consistent with a constant orbital period, giving no compelling evidence for period variations that would be produced by a satellite or additional planets. Analysis of the new photometry, in combination with stellar-evolutionary modeling, gives a planetary mass and radius of 1.237+/-0.064M_Jup_ and 1.365+/-0.021R_Jup_, respectively. The planet is 15% larger than expected based on previously published models of solar-composition giant planets. With data of the quality presented here, the detection of transits of a "super-Earth" of radius 1.75R_{earth}_ would have been possible.
- ID:
- ivo://CDS.VizieR/J/ApJ/753/156
- Title:
- T/Y brown dwarfs with WISE photometry
- Short Name:
- J/ApJ/753/156
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present the discovery of another seven Y dwarfs from the Wide-field Infrared Survey Explorer (WISE). Using these objects, as well as the first six WISE Y dwarf discoveries from Cushing et al. (2011ApJ...743...50C), we further explore the transition between spectral types T and Y. We find that the T/Y boundary roughly coincides with the spot where the J-H colors of brown dwarfs, as predicted by models, turn back to the red. Moreover, we use preliminary trigonometric parallax measurements to show that the T/Y boundary may also correspond to the point at which the absolute H (1.6{mu}m) and W2 (4.6{mu}m) magnitudes plummet. We use these discoveries and their preliminary distances to place them in the larger context of the solar neighborhood. We present a table that updates the entire stellar and substellar constituency within 8pc of the Sun, and we show that the current census has hydrogen-burning stars outnumbering brown dwarfs by roughly a factor of six. This factor will decrease with time as more brown dwarfs are identified within this volume, but unless there is a vast reservoir of cold brown dwarfs invisible to WISE, the final space density of brown dwarfs is still expected to fall well below that of stars. We also use these new Y dwarf discoveries, along with newly discovered T dwarfs from WISE, to investigate the field substellar mass function. We find that the overall space density of late-T and early-Y dwarfs matches that from simulations describing the mass function as a power law with slope -0.5<{alpha}<0.0; however, a power law may provide a poor fit to the observed object counts as a function of spectral type because there are tantalizing hints that the number of brown dwarfs continues to rise from late-T to early-Y. More detailed monitoring and characterization of these Y dwarfs, along with dedicated searches aimed at identifying more examples, are certainly required.
