- ID:
- ivo://CDS.VizieR/J/ApJ/896/122
- Title:
- BAT AGN Spectroscopic Survey. XVIII. Periodic var.
- Short Name:
- J/ApJ/896/122
- Date:
- 03 Dec 2021 13:15:09
- Publisher:
- CDS
- Description:
- Theory predicts that a supermassive black hole binary (SMBHB) could be observed as a luminous active galactic nucleus (AGN) that periodically varies on the order of its orbital timescale. In X-rays, periodic variations could be caused by mechanisms including relativistic Doppler boosting and shocks. Here we present the first systematic search for periodic AGNs using 941 hard X-ray light curves (14-195keV) from the first 105 months of the Swift Burst Alert Telescope (BAT) survey (2004-2013). We do not find evidence for periodic AGNs in Swift-BAT, including the previously reported SMBHB candidate MCG+11-11-032. We find that the null detection is consistent with the combination of the upper-limit binary population in AGNs in our adopted model, their expected periodic variability amplitudes, and the BAT survey characteristics. We have also investigated the detectability of SMBHBs against normal AGN X-ray variability in the context of the extended ROentgen Survey with an Imaging Telescope Array (eROSITA) survey. Under our assumptions of a binary population and the periodic signals they produce, which have long periods of hundreds of days, up to 13% true periodic binaries can be robustly distinguished from normal variable AGNs with the ideal uniform sampling. However, we demonstrate that realistic eROSITA sampling is likely to be insensitive to long-period binaries because longer observing gaps reduce their detectability. In contrast, large observing gaps do not diminish the prospect of detecting binaries of short, few-day periods, as 19% can be successfully recovered, the vast majority of which can be identified by the first half of the survey.
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- ID:
- ivo://CDS.VizieR/J/ApJS/252/29
- Title:
- BAT AGN Spectroscopic Survey. XX. Molecular gas
- Short Name:
- J/ApJS/252/29
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present the host-galaxy molecular gas properties of a sample of 213 nearby (0.01<z<0.05) hard-X-ray-selected active galactic nucleus (AGN) galaxies, drawn from the 70-month catalog of Swift's Burst Alert Telescope (BAT), with 200 new CO(2-1) line measurements obtained with the James Clerk Maxwell Telescope and the Atacama Pathfinder Experiment telescope. We find that AGN in massive galaxies (log(M_*_/M_{sun}_)>10.5) tend to have more molecular gas and higher gas fractions than inactive galaxies matched in stellar mass. When matched in star formation, we find AGN galaxies show no difference from inactive galaxies, with no evidence that AGN feedback affects the molecular gas. The higher molecular gas content is related to AGN galaxies hosting a population of gas-rich early types with an order of magnitude more molecular gas and a smaller fraction of quenched, passive galaxies (~5% versus 49%) compared to inactive galaxies. The likelihood of a given galaxy hosting an AGN (L_bol_>10^44^erg/s) increases by ~10-100 between a molecular gas mass of 10^8.7^M_{sun}_ and 10^10.2^M_{sun}_. AGN galaxies with a higher Eddington ratio (log(L/L_Edd_)>-1.3) tend to have higher molecular gas masses and gas fractions. The log(NH/cm^-2^)>23.4) of AGN galaxies with higher column densities are associated with lower depletion timescales and may prefer hosts with more gas centrally concentrated in the bulge that may be more prone to quenching than galaxy-wide molecular gas. The significant average link of host-galaxy molecular gas supply to supermassive black hole (SMBH) growth may naturally lead to the general correlations found between SMBHs and their host galaxies, such as the correlations between SMBH mass and bulge properties, and the redshift evolution of star formation and SMBH growth.
183. BAT X-ray survey. I.
- ID:
- ivo://CDS.VizieR/J/ApJ/678/102
- Title:
- BAT X-ray survey. I.
- Short Name:
- J/ApJ/678/102
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We applied the maximum likelihood (ML) method, as an image reconstruction algorithm, to the BAT (Burst Alert Telescope) X-Ray Survey (BXS). This method was specifically designed to preserve the full statistical information in the data and to avoid mosaicking of many exposures with different pointing directions, thus reducing systematic errors when co-adding images. We reconstructed, in the 14-170keV energy band, the image of a 90x90deg^2^ sky region, centered on (RA, DE)=(105{deg}, -25{deg}), which BAT surveyed with an exposure time of ~1Ms (in 2005 November). The best sensitivity in our image is ~0.85mCrab or 2.0x10^-11^ergs/cm^2^. We detect 49 hard X-ray sources above the 4.5{sigma} level; of these, only 12 were previously known as hard X-ray sources (>15keV). Swift XRT observations allowed us to firmly identify the counterparts for 15 objects, while 2 objects have Einstein IPC counterparts (Harris et al., 1990, in Imaging X-Ray Astronomy. A Decade of Achievements, ed. M. Elvis (Cambridge: Cambridge Univ. Press), 309); in addition to those, we found a likely counterpart for 13 objects by correlating our sample with the ROSAT All-Sky Survey Bright Source Catalog (Voges et al., 1999, Cat. <IX/10>). Seven objects remain unidentified.
- ID:
- ivo://CDS.VizieR/J/MNRAS/444/3517
- Title:
- BCool survey of solar-type stars
- Short Name:
- J/MNRAS/444/3517
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present the results of a major high-resolution spectropolarimetric BCool project magnetic survey of 170 solar-type stars. Surface magnetic fields were detected on 67 stars, with 21 classified as mature solar-type stars, a result that increases by a factor of 4 the number of mature solar-type stars on which magnetic fields have been observed. In addition, a magnetic field was detected for 3 out of 18 of the subgiant stars surveyed. For the population of K-dwarfs, the mean value of |Bl| (|Bl|_mean_) was also found to be higher (5.7G) than |Bl|_mean_ measured for the G-dwarfs (3.2G) and the F-dwarfs (3.3G). For the sample as a whole, |Bl|_mean_ increases with rotation rate and decreases with age, and the upper envelope for |Bl| correlates well with the observed chromospheric emission. Stars with a chromospheric S-index greater than about 0.2 show a high magnetic field detection rate and so offer optimal targets for future studies. This survey constitutes the most extensive spectropolarimetric survey of cool stars undertaken to date, and suggests that it is feasible to pursue magnetic mapping of a wide range of moderately active solar-type stars to improve our understanding of their surface fields and dynamos.
- ID:
- ivo://CDS.VizieR/J/ApJS/79/77
- Title:
- Bell Lab. H I Survey - High Velocity Clouds
- Short Name:
- J/ApJS/79/77
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The sky north of declination -40 deg. was observed in the 21 cm line of atomic hydrogen with the FWHM = 2 deg. beam of the 20 foot horn reflector at AT&T Bell Laboratories, Crawford Hill. The survey covers a velocity range of 654 km/s centered on the Galactic standard of rest, with 5.3 km/s wide filters. This survey is distinguished by its sensitivity to low surface brightness features (antenna temperature about 50 mK) and relative freedom from sidelobe contamination. The high-velocity cloud list was extracted and catalogued automatically from the survey data.
- ID:
- ivo://CDS.VizieR/VIII/10
- Title:
- Bell Laboratories H I Profiles
- Short Name:
- VIII/10
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- This survey consists of H I 21-cm spectra covering galactic latitudes |b|>10degrees, North of Declination -40deg, observed with the 20-foot horn reflector at AT&T Bell Laboratories, Crawford Hill. The instrument beam is 2{deg} (FWHM). The data consist of 124-channel profiles sorted in Galactic latitude and longitude; each channel has a width of 5.3km/s. The data were obtained by holding the telescope fixed and letting the sky drift through. Then the natural coordinate system for the data is in equatorial coordinates, so the data are not gridded in Galactic coordinates. Note that this catalog represents the Bell Laboratories H I Survey in a preliminary version; it is superseded by Catalog VIII/28.
- ID:
- ivo://CDS.VizieR/VIII/28
- Title:
- Bell Laboratories H I Survey
- Short Name:
- VIII/28
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The sky north of declination -40{deg} was observed in the 21cm line of atomic hydrogen with the FWHM=2{deg} beam of the 20 foot horn reflector at AT&T Bell Laboratories, Crawford Hill. The survey covers a velocity range of 654km/s centered on the Galactic standard of rest, with 5.3km/s wide filters. This survey is distinguished by its sensitivity to low surface brightness features (antenna temperature about 50mK) and relative freedom from sidelobe contamination. High-velocity clouds are extracted and catalogued automatically. The data are presented in declination zones in equatorial and polar coordinates, and as R.A. - velocity images.
- ID:
- ivo://CDS.VizieR/J/ApJS/195/9
- Title:
- BeppoSAX/WFC: source list
- Short Name:
- J/ApJS/195/9
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- During the operational life of the Italian/Dutch X-ray satellite (1996-2002), BeppoSAX, its two Wide Field Cameras (WFCs) performed observations that covered the full sky at different epochs. Although the majority of analysis performed on BeppoSAX WFC data concentrated on the detection of transient sources, we have now applied the same techniques developed for the INTEGRAL/IBIS survey to produce the same work with the BeppoSAX WFC data. This work represents the first unbiased source list compilation produced from the overall WFC data set optimized for faint persistent source detection. This approach recovered 182 more sources compared to the previous WFC catalog reported in Verrecchia et al. (Cat. J/A+A/472/705). The catalog contains 404 sources detected between 3 and 17keV, 10 of which are yet to be seen by the new generation of telescopes.
- ID:
- ivo://CDS.VizieR/VIII/11
- Title:
- Berkeley Low-Latitude H I Survey
- Short Name:
- VIII/11
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- This survey consists of H I 21-cm spectra covering galactic latitudes from -10 degrees to +10 degrees and galactic longitudes from 10degrees to 250degrees. The observations were made with the Hat Creek 85-foot telescope between 1968 and 1970. The individual spectra contain 238 points per profile spaced every 5kHz and cover a velocity range of 250km/s. The velocity resolution is 2km/s (half-power of each filter) and the half-power beamwidth is 35arcmin. The spacing between points observed on the sky are 0.25degrees in galactic latitude and 0.5degrees in galactic longitude. Each spectrum or record consists of a header followed by 238 antenna temperatures. The header contains the galactic longitude, galactic latitude, and central velocity (LSR). The catalog contains a total of 38961 spectra.
- ID:
- ivo://CDS.VizieR/J/MNRAS/474/5287
- Title:
- BeSOS Be stars stellar parameters
- Short Name:
- J/MNRAS/474/5287
- Date:
- 07 Dec 2021 13:16:10
- Publisher:
- CDS
- Description:
- The Be phenomenon is present in about 20 per cent of B-type stars. Be stars show variability on a broad range of time-scales, which in most cases is related to the presence of a circumstellar disc of variable size and structure. For this reason, a time-resolved survey is highly desirable in order to understand the mechanisms of disc formation, which are still poorly understood. In addition, a complete observational sample would improve the statistical significance of the study of stellar and disc parameters. The 'Be Stars Observation Survey' (BeSOS) is a survey containing reduced spectra obtained using the Pontifica Universidad Catolica High Echelle Resolution Optical Spectrograph (PUCHEROS) with a spectral resolution of 17000 in the range 4260-7300{AA}. BeSOS's main objective is to offer consistent spectroscopic and time-resolved data obtained with one instrument. The user can download or plot the data and obtain stellar parameters directly from the website. We also provide a star-by-star analysis based on photometric, spectroscopic and interferometric data, as well as general information about the whole BeSOS sample. Recently, BeSOS led to the discovery of a new Be star HD 42167 and facilitated study of the V/R variation of HD 35165 and HD 120324, the steady disc of HD 110335 and the Be shell status of HD 127972. Optical spectra used in this work, as well as the stellar parameters derived, are available online at http://besos.ifa.uv.cl.