- ID:
- ivo://CDS.VizieR/J/ApJS/187/64
- Title:
- The simultaneous optical-to-X-ray SED of AGNs
- Short Name:
- J/ApJS/187/64
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We report Swift observations of a sample of 92 bright soft X-ray selected active galactic nuclei (AGNs). This sample represents the largest number of AGNs observed to study the spectral energy distribution (SED) of AGNs with simultaneous optical/UV and X-ray data. The principal motivation of this study is to understand the SEDs of AGNs in the optical/UV to X-ray regime and to provide bolometric corrections which are important in determining the Eddington ratio L/L_Edd_. In particular, we rigorously explore the dependence of the UV-EUV contribution to the bolometric correction on the assumed EUV spectral shape. We find strong correlations of the spectral slopes {alpha}_X_ and {alpha}_UV_ with L/L_Edd_.
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19102. The SkyMapper DR3 SSOs
- ID:
- ivo://CDS.VizieR/J/A+A/658/A109
- Title:
- The SkyMapper DR3 SSOs
- Short Name:
- J/A+A/658/A109
- Date:
- 22 Feb 2022
- Publisher:
- CDS
- Description:
- The populations of small bodies of the Solar System (asteroids, comets, and Kuiper Belt objects) are used to constrain the origin and evolution of the Solar System. Their orbital distribution and composition distribution are both required to track the dynamical pathway from their formation regions to their current locations. We aim to increase the sample of Solar System objects (SSOs) that have multifilter photometry and compositional taxonomy. Methods. We searched for moving objects in the SkyMapper Southern Survey. We used the predicted SSO positions to extract photometry and astrometry from the SkyMapper frames. We then applied a suite of filters to clean the catalog from false-positive detections. We finally used the near-simultaneous photometry to assign a taxonomic class to objects. We release a catalog of 880,528 individual observations, consisting of 205515 known and unique SSOs. The catalog completeness is estimated to be about 97% down to V=18mag and the purity is higher than 95% for known SSOs. The near-simultaneous photometry provides either three, two, or a single color that we use to classify 117356 SSOs with a scheme consistent with the widely used Bus-DeMeo taxonomy. The present catalog contributes significantly to the sample of asteroids with known surface properties (about 40% of main-belt asteroids down to an absolute magnitude of 16). We will release more observations of SSOs with future SkyMapper data releases.
- ID:
- ivo://CDS.VizieR/J/ApJ/705/1099
- Title:
- The Sloan Lens ACS (SLACS) Survey. IX.
- Short Name:
- J/ApJ/705/1099
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present the current photometric data set for the Sloan Lens ACS (SLACS) Survey, including Hubble Space Telescope (HST) photometry from Advanced Camera for Surveys, WFPC2, and NICMOS. These data have enabled the confirmation of an additional 15 grade "A" (certain) lens systems, bringing the number of SLACS grade "A" lenses to 85; including 13 grade "B" (likely) systems, SLACS has identified nearly 100 lenses and lens candidates. Approximately 80% of the grade "A" systems have elliptical morphologies while ~10% show spiral structure; the remaining lenses have lenticular morphologies. Spectroscopic redshifts for the lens and source are available for every system, making SLACS the largest homogeneous data set of galaxy-scale lenses to date. The ensemble properties of the SLACS lens galaxies, e.g., stellar masses and projected ellipticities, appear to be indistinguishable from other SDSS galaxies with similar stellar velocity dispersions. This further supports that SLACS lenses are representative of the overall population of massive early-type galaxies with M_*_>~10^11^M_{sun}_, and are therefore an ideal data set to investigate the kpc-scale distribution of luminous and dark matter in galaxies out to z~0.5.
- ID:
- ivo://CDS.VizieR/J/ApJ/690/670
- Title:
- The Sloan lens ACS Survey. VIII.
- Short Name:
- J/ApJ/690/670
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We study the relation between the internal structure of early-type galaxies and their environment using 70 strong gravitational lenses from the SLACS Survey. The Sloan Digital Sky Survey (SDSS) database is used to determine two measures of overdensity of galaxies around each lens - the projected number density of galaxies inside the tenth nearest neighbor ({Sigma}_10_) and within a cone of radius 1h^-1^Mpc (D1).
19105. The SMC in the Far Infrared
- ID:
- ivo://CDS.VizieR/J/A+A/401/873
- Title:
- The SMC in the Far Infrared
- Short Name:
- J/A+A/401/873
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The ISOPHOT experiment onboard the ISO satellite generated a complete view of the Small Magellanic Cloud (SMC) at 170{mu}m with 1.5arcmin resolution. The map is analysed using an automated photometry program enabling accurate photometric characterization of the far infrared (FIR) emitting regions. In this paper, the sources detected at 170{mu}m are compared with those obtainable from the IRAS satellite data. For this purpose, the 12{mu}m, 25{mu}m, 60{mu}m, and 100{mu}m IRAS high resolution (HiRes) maps of the SMC are re-examined using the same method. In contrast to former studies, this provides an all-band ISO/IRAS source catalog which is no longer based on eyeball classification, but relies on an algorithm which is capable of automated, repeatable photometry, even for irregular sources. In the mid infrared IRAS bands numerous bright FIR emitting regions in the SMC are detected and classified: 73 sources are found at 12{mu}m, 135 at 25{mu}m (most of them with F{nu}<1.0Jy). All three FIR bands at 170{mu}m, 100{mu}m, and 60{mu}m reproduce the overall morphological structure of the SMC similarly well, in contrast to the 12{mu}m and 25{mu}m maps which only contain a limited number of extended sources and do not trace the main body of the SMC. 243 sources are detected in the ISO 170{mu}m map, 155 of them with F{nu}>=2.0Jy. Comparable numbers are found for the two FIR IRAS maps at 60{mu}m (384) and 100{mu}m (338) with fluxes up to 450Jy. 70 of the 243 170{mu}m sources are assigned a general SED type (cold , warm , i.e., <30K, >30K) for the first time. A comparison with earlier IRAS results suggests that many source flux densities in those studies have been under- or overestimated because of non-standardized fitting methods. Many sources with flux densities up to 40Jy listed in former catalogs cannot be identified in our data.
- ID:
- ivo://CDS.VizieR/J/ApJS/120/409
- Title:
- The SMM Atlas of Gamma-Ray flares
- Short Name:
- J/ApJS/120/409
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present a compilation of data for all 258 gamma-ray flares detected above 300 keV by the Gamma Ray Spectrometer (GRS) aboard the Solar Maximum Mission satellite. This gamma-ray flare sample was collected during the period from 1980 February to 1989 November; covering the latter half of the 21st solar sunspot cycle and the onset of the 22d solar sunspot cycle. We describe the SMM/GRS instrument, its in-orbit operation, and the principal data reduction methods used to derive the gamma-ray flare properties. Utilizing measurements for 185 flares that were sufficiently intense to allow the derivation of gamma-ray spectra, we present an atlas of time profiles and gamma-ray spectra. The flare parameters derived from the gamma-ray spectra include bremsstrahlung fluence and best-fit power-law parameters, narrow nuclear line fluence, positron annihilation line fluence, neutron capture line fluence, and an indication of whether or not emissions greater than 10 MeV were present. Since a uniform methodology was adopted for deriving the parameters, this atlas should be very useful for future statistical and correlative studies of solar flares.
19107. The solar CNO abundances
- ID:
- ivo://CDS.VizieR/J/A+A/656/A113
- Title:
- The solar CNO abundances
- Short Name:
- J/A+A/656/A113
- Date:
- 22 Feb 2022
- Publisher:
- CDS
- Description:
- Carbon, nitrogen, and oxygen are the fourth, sixth, and third most abundant elements in the Sun. Their abundances remain hotly debated due to the so-called solar modelling problem that has persisted for almost 20 years. We revisit this issue by presenting a homogeneous analysis of 408 molecular lines across 12 diagnostic groups, observed in the solar intensity spectrum. Using a realistic 3D radiative-hydrodynamic model solar photosphere and local thermodynamic equilibrium (LTE) line formation, we find log{epsilon}C=8.47+/-0.02, log{epsilon}N=7.89+/-0.04, and log{epsilon}O=8.70+/-0.04. The stipulated uncertainties mainly reflect the sensitivity of the results to the model atmosphere; this sensitivity is correlated between the different diagnostic groups, which all agree with the mean result to within 0.03dex. For carbon and oxygen, the molecular results are in excellent agreement with our 3D non-LTE analyses of atomic lines. For nitrogen, however, the molecular indicators give a 0.12dex larger abundance than the atomic indicators, and our best estimate of the solar nitrogen abundance is given by the mean: 7.83dex. The solar oxygen abundance advocated here is close to our earlier determination of 8.69dex, and so the present results do not significantly alleviate the solar modelling problem.
- ID:
- ivo://CDS.VizieR/J/ApJ/847/115
- Title:
- The solar flare complex network
- Short Name:
- J/ApJ/847/115
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We investigate the characteristics of the solar flare complex network. The limited predictability, nonlinearity, and self-organized criticality of the flares allow us to study systems of flares in the field of the complex systems. Both the occurrence time and the location of flares detected from 2006 January 1 to 2016 July 21 are used to design the growing flares network. The solar surface is divided into cells with equal areas. The cells, which include flares, are considered nodes of the network. The related links are equivalent to sympathetic flaring. The extracted features demonstrate that the network of flares follows quantitative measures of complexity. The power-law nature of the connectivity distribution with a degree exponent greater than three reveals that flares form a scale-free and small-world network. A large value for the clustering coefficient, a small characteristic path length, and a slow change of the diameter are all characteristics of the flares network. We show that the degree correlation of the flares network has the characteristics of a disassortative network. About 11% of the large energetic flares (M and X types in GOES classification) that occurred in the network hubs cover 3% of the solar surface.
- ID:
- ivo://CDS.VizieR/J/A+A/643/A146
- Title:
- The solar gravitational redshift
- Short Name:
- J/A+A/643/A146
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The General Theory of Relativity predicts the redshift of spectral lines in the solar photosphere, as a consequence of the gravitational potential of the Sun. This effect can be measured from a solar disk-integrated flux spectrum of the Sun's reflected light on solar system bodies. The laser frequency comb (LFC) calibration system attached to the HARPS spectrograph offers the possibility to perform an accurate measurement of the solar gravitational redshift (GRS) by observing the Moon or other solar system bodies. We have analysed the line shift observed in Fe absorption lines from five high-quality HARPS-LFC spectra of the Moon. We select an initial sample of 326 photospheric Fe lines in the spectral range 476-585nm and measure their line positions and equivalent widths (EWs). Accurate line shifts are derived from the wavelength position of the core of the lines compared with the laboratory wavelengths of Fe lines. We also use a CO^5^BOLD 3D hydrodynamical model atmosphere of the Sun to compute 3D synthetic line profiles of a subsample of about 200 spectral Fe lines centred at their laboratory wavelengths. We fit the observed relatively weak spectral Fe lines (with EW<180m{AA}) with the 3D synthetic profiles. Convective motions in the solar photosphere do not affect the line cores of Fe lines stronger than about 150m{AA}. In our sample, only 15 FeI lines have EWs in the range 150<EW(m{AA})<550, providing a measurement of the solar GRS at 639+/-14m/s, consistent with the expected theoretical value on Earth of 633.1m/s. A final sample of about 98 weak Fe lines with EW<180m{AA} allows us to derive a mean global line shift of 638+/-6m/s in agreement with the theoretical solar GRS. These are the most accurate measurements of the solar GRS so far. Ultrastable spectrographs calibrated with the LFC over a larger spectral range, such as HARPS or ESPRESSO, together with a further improvement on the laboratory wavelengths, could provide a more robust measurement of the solar GRS and further tests for the 3D hydrodynamical models.
- ID:
- ivo://CDS.VizieR/J/AJ/156/49
- Title:
- The solar neighborhood. XLIII. New nearby stars
- Short Name:
- J/AJ/156/49
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We have conducted a novel search of most of the southern sky for nearby red dwarfs having low proper motions, with specific emphasis on those with {mu}<0.18"/yr, the lower cutoff of Luyten's classic proper-motion catalog. We used a tightly constrained search of the SuperCOSMOS database and a suite of photometric distance relations for photographic BRI and 2MASS JHK_s_ magnitudes to estimate distances to more than 14 million red dwarf candidates. Here we discuss 29 stars in 26 systems estimated to be within 25 pc, all of which have {mu}<0.18"/yr, that we have investigated using milliarcsecond astrometry, VRI photometry, and low-resolution spectroscopy. In total, we present the first parallaxes of 20 star systems, 9 of which are within 25 pc. We have additionally identified 14 young M dwarfs, of which 3 are new members of the nearby young moving groups, and 72 new giants, including two new carbon stars. We also present the entire catalog of 1215 sources we have identified by this means.