- ID:
- ivo://CDS.VizieR/J/ApJ/894/78
- Title:
- Strong gravitational lenses from DECaLS
- Short Name:
- J/ApJ/894/78
- Date:
- 03 Dec 2021 00:50:48
- Publisher:
- CDS
- Description:
- We perform a semi-automated search for strong gravitational lensing systems in the 9000 deg2 Dark Energy Camera Legacy Survey (DECaLS), part of the Dark Energy Spectroscopic Instrument Legacy Imaging Surveys. The combination of the depth and breadth of these surveys are unparalleled at this time, making them particularly suitable for discovering new strong gravitational lensing systems. We adopt the deep residual neural network architecture developed by Lanusse+ (2018MNRAS.473.3895L) for the purpose of finding strong lenses in photometric surveys. We compile a training sample that consists of known lensing systems in the Legacy Surveys and the Dark Energy Survey as well as non-lenses in the footprint of DECaLS. In this paper we show the results of applying our trained neural network to the cutout images centered on galaxies typed as ellipticals in DECaLS. The images that receive the highest scores (probabilities) are visually inspected and ranked. Here we present 335 candidate strong lensing systems, identified for the first time.
Number of results to display per page
Search Results
- ID:
- ivo://CDS.VizieR/J/AJ/129/682
- Title:
- Structural properties of S+S galaxies
- Short Name:
- J/AJ/129/682
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present a structural analysis of nearby galaxies in spiral-spiral pairs in optical BVRI bands and compare them with the structures of isolated spiral galaxies and galaxies in ongoing mergers. We use these comparisons to determine how galaxy structure changes during galaxy interactions and mergers. We analyze light concentration (C), asymmetry (A), and clumpiness (S) parameters, and use the projections of CAS parameter space to compare these samples.
- ID:
- ivo://CDS.VizieR/J/AZh/77/3
- Title:
- Studies of Bright Steep-Spectrum Radio Sources
- Short Name:
- J/AZh/77/3
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Results of studies of bright radio sources in the constellation Cetus are presented. More than 50% of the sources have radio spectral indices steeper than 0.9. Optical identifications have been determined for 35 sources. A large fraction of the radio sources are identified with weak blue galaxies. Given their spectral indices, it is likely that these objects have redshift z=0.4-1.0. More than 20% of the steep-spectrum sources do not have optical identifications and appear to be weak galaxies with z>2.
- ID:
- ivo://CDS.VizieR/III/147
- Title:
- Studies of LMC stellar content
- Short Name:
- III/147
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- A spectral survey has been made during the period 1971 to 1975 with the ESO 40cm astrograph at La Silla, equipped with its normal prism, giving an intermediate dispersion of 95Angstroem/mm at 4026Angstroem. Long exposure plates taken directly or with an interference filter enabled us to obtain spectral types for nearly 1600 stars. In parallel, a V photographic survey has been carried out during the same period with the same astrograph and has led to the determination of V magnitudes for more that 700 stars having no previous photometric data. New spectroscopic and photometric results as well as previous photoelectric UBV values are given in the catalogue together with additional remarks concerning peculiarities of spectra, V magnitudes, and details on double and multiple systems.
- ID:
- ivo://CDS.VizieR/J/ApJ/810/116
- Title:
- S-type AGB stars in SMC
- Short Name:
- J/ApJ/810/116
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We have identified a new class of Asymptotic Giant Branch (AGB) stars in the Small and Large Magellanic Clouds (SMC/LMC) using optical to infrared photometry, light curves, and optical spectroscopy. The strong dust production and long-period pulsations of these stars indicate that they are at the very end of their AGB evolution. Period-mass-radius relations for the fundamental-mode pulsators give median current stellar masses of 1.14M_{sun}_ in the LMC and 0.94M_{sun}_ in the SMC (with dispersions of 0.21 and 0.18M_{sun}_, respectively), and models suggest initial masses of <1.5M_{sun}_ and <1.25 M_{sun}_, respectively. This new class of stars includes both O-rich and C-rich chemistries, placing the limit where dredge-up allows carbon star production below these masses. A high fraction of the brightest among them should show S star characteristics indicative of atmospheric C/O~1, and many will form O-rich dust prior to their C-rich phase. These stars can be separated from their less-evolved counterparts by their characteristically red J-[8] colors.
- ID:
- ivo://CDS.VizieR/J/AJ/128/426
- Title:
- Subdwarfs in the SDSS
- Short Name:
- J/AJ/128/426
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present a spectroscopic analysis of nearly 8000 late-type dwarfs in the Sloan Digital Sky Survey. Using the H{alpha} emission line as an activity indicator, we investigate the fraction of active stars as a function of spectral type and find a peak near type M8, confirming previous results.
- ID:
- ivo://CDS.VizieR/J/ApJS/214/19
- Title:
- Suprime-Cam wide-field photometry of Leo A
- Short Name:
- J/ApJS/214/19
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We have surveyed a complete extent of Leo A --an apparently isolated gas-rich low-mass dwarf irregular galaxy in the Local Group. The B, V, and I passband CCD images (typical seeing ~0.8") were obtained with the Subaru Telescope equipped with the Suprime-Cam mosaic camera. The wide-field (20'x24') photometry catalog of 38856 objects (V~16-26mag) is presented. This survey is also intended to serve as "a finding chart" for future imaging and spectroscopic observation programs of Leo A.
- ID:
- ivo://CDS.VizieR/J/A+A/296/665
- Title:
- Survey of optically variables QSOs
- Short Name:
- J/A+A/296/665
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We describe a survey for variable QSOs carried out for 15 years with the UK Schmidt telescope, using IIIaJ plates exposed behind a Schott GG395 filter. Objects brighter than B=21.0 on a reference plate and displaying a peak to peak amplitude of variability larger than B=0.35mag are selected. Plates in U, V, R and I were also obtained.
- ID:
- ivo://CDS.VizieR/J/ApJ/870/123
- Title:
- Swift optical & UV flux of four AGNs
- Short Name:
- J/ApJ/870/123
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Swift intensive accretion disk reverberation mapping of four AGN yielded light curves sampled ~200-350 times in 0.3-10keV X-ray and six UV/optical bands. Uniform reduction and cross-correlation analysis of these data sets yields three main results: (1) The X-ray/UV correlations are much weaker than those within the UV/optical, posing severe problems for the lamp-post reprocessing model in which variations in a central X-ray corona drive and power those in the surrounding accretion disk. (2) The UV/optical interband lags are generally consistent with {tau}{propto}{lambda}^4/3^ as predicted by the centrally illuminated thin accretion disk model. While the average interband lags are somewhat larger than predicted, these results alone are not inconsistent with the thin disk model given the large systematic uncertainties involved. (3) The one exception is the U band lags, which are on average a factor of ~2.2 larger than predicted from the surrounding band data and fits. This excess appears to be due to diffuse continuum emission from the broad-line region (BLR). The precise mixing of disk and BLR components cannot be determined from these data alone. The lags in different AGN appear to scale with mass or luminosity. We also find that there are systematic differences between the uncertainties derived by Just Another Vehicle for Estimating Lags In Nuclei (JAVELIN) versus more standard lag measurement techniques, with JAVELIN reporting smaller uncertainties by a factor of 2.5 on average. In order to be conservative only standard techniques were used in the analyses reported herein.
- ID:
- ivo://CDS.VizieR/J/ApJ/836/232
- Title:
- Swift-UVOT obs. analysis of 29 SNe Ia
- Short Name:
- J/ApJ/836/232
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The intrinsic colors of Type Ia supernovae (SNe Ia) are important to understanding their use as cosmological standard candles. Understanding the effects of reddening and redshift on the observed colors are complicated and dependent on the intrinsic spectrum, the filter curves, and the wavelength dependence of reddening. We present ultraviolet and optical data of a growing sample of SNe Ia observed with the Ultraviolet/Optical Telescope on the Swift spacecraft and use this sample to re-examine the near-UV (NUV) colors of SNe Ia. We find that a small amount of reddening (E(B-V)=0.2mag) could account for the difference between groups designated as NUV-blue and NUV-red, and a moderate amount of reddening (E(B-V)=0.5mag) could account for the whole NUV-optical differences. The reddening scenario, however, is inconsistent with the mid-UV colors and color evolution. The effect of redshift alone only accounts for part of the variation. Using a spectral template of SN2011fe, we can forward model the effects of redshift and reddening and directly compare those with the observed colors. We find that some SNe are consistent with reddened versions of SN2011fe, but most SNe Ia are much redder in the uvw1-v color than SN2011fe reddened to the same b-v color. The absolute magnitudes show that two out of five NUV-blue SNe Ia are blue because their near-UV luminosity is high, and the other three are optically fainter. We also show that SN 2011fe is not a "normal" SN Ia in the UV, but has colors placing it at the blue extreme of our sample.
