- ID:
- ivo://CDS.VizieR/J/ApJ/882/120
- Title:
- CfA, CSP, BSP and LOSS spec. & phot. of SNe Ia
- Short Name:
- J/ApJ/882/120
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- SNe Ia play key roles in revealing the accelerating expansion of the universe, but our knowledge of their progenitors is still very limited. Here we report the discovery of a rigid dichotomy in circumstellar (CS) environments around two subclasses of SNe Ia as defined by their distinct photospheric velocities. For the SNe Ia with high photospheric velocities (HVs), we found a significant excess flux in blue light 60-100 days past maximum, while this phenomenon is absent for SNe with normal photospheric velocity. This blue excess can be attributed to light echoes by circumstellar dust located at a distance of about (1-2)x10^17^cm from the HV subclass. Moreover, we also found that the HV SNe Ia show systematically evolving NaI absorption line by performing a systematic search of variable NaI absorption lines in spectra of all SNe Ia, whereas this evolution is rarely seen in normal ones. The evolving NaI absorption can be modeled in terms of photoionization model, with the location of the gas clouds at a distance of about 2x10^17^cm, in striking agreement with the location of CS dust inferred from B-band light-curve excess. These observations show clearly that the progenitors of HV subclass are likely from single-degenerate progenitor system (i.e., symbiotic binary), while the NV subclass may arise from double-degenerate system.
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Search Results
- ID:
- ivo://CDS.VizieR/J/AJ/104/1706
- Title:
- CFH Blue Grens Quasar Candidates
- Short Name:
- J/AJ/104/1706
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- (no description available)
293. CF-HiZELS survey
- ID:
- ivo://CDS.VizieR/J/MNRAS/451/2303
- Title:
- CF-HiZELS survey
- Short Name:
- J/MNRAS/451/2303
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present results from the largest contiguous narrow-band survey in the near-infrared. We have used the wide-field infrared camera/Canada-France-Hawaii Telescope and the lowOH2 filter (1.187+/-0.005{mu}m) to survey ~10deg^2^ of contiguous extragalactic sky in the SA22 field. A total of ~6000 candidate emission-line galaxies are found. We use deep ugrizJK data to obtain robust photometric redshifts. We combine our data with the High-redshift(Z) Emission Line Survey (HiZELS), explore spectroscopic surveys (VVDS, VIPERS) and obtain our own spectroscopic follow-up with KMOS, FMOS and MOSFIRE to derive large samples of high-redshift emission-line selected galaxies: 3471 H{alpha} emitters at z=0.8, 1343 [OIII] + H{beta} emitters at z=1.4 and 572 [OII] emitters at z=2.2. We probe comoving volumes of >10^6^Mpc^3^ and find significant overdensities, including an 8.5{sigma} (spectroscopically confirmed) overdensity of H{alpha} emitters at z=0.81. We derive H{alpha}, [OIII] + H{beta} and [OII] luminosity functions at z=0.8, 1.4, 2.2, respectively, and present implications for future surveys such as Euclid. Our uniquely large volumes/areas allow us to subdivide the samples in thousands of randomized combinations of areas and provide a robust empirical measurement of sample/cosmic variance. We show that surveys for star-forming/emission-line galaxies at a depth similar to ours can only overcome cosmic-variance (errors <10 percent) if they are based on volumes >5x10^5^Mpc^3^; errors on L* and {phi}* due to sample (cosmic) variance on surveys probing ~10^4^ and ~10^5^Mpc^3^ are typically very high: ~300 and ~40-60 percent, respectively.
- ID:
- ivo://CDS.VizieR/J/ApJ/765/28
- Title:
- CFHTLS galaxies with faint tidal features
- Short Name:
- J/ApJ/765/28
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present an analysis of the detectability of faint tidal features in galaxies from the wide-field component of the Canada-France-Hawaii Telescope Legacy Survey. Our sample consists of 1781 luminous (M_r'_<-19.3mag) galaxies in the magnitude range 15.5mag<r'<17mag and in the redshift range 0.04<z<0.2. Although we have classified tidal features according to their morphology (e.g., streams, shells, and tails), we do not attempt to interpret them in terms of their physical origin (e.g., major versus minor merger debris). Instead, we provide a catalog that is intended to provide raw material for future investigations which will probe the nature of low surface brightness substructure around galaxies. We find that around 12% of the galaxies in our sample show clear tidal features at the highest confidence level. This fraction rises to about 18% if we include systems with convincing, albeit weaker tidal features, and to 26% if we include systems with more marginal features that may or may not be tidal in origin. These proportions are a strong function of rest-frame color and of stellar mass. Linear features, shells, and fans are much more likely to occur in massive galaxies with stellar masses >10^10.5^M_{sun}_, and red galaxies are twice as likely to show tidal features than are blue galaxies.
- ID:
- ivo://CDS.VizieR/J/ApJ/749/38
- Title:
- CFHTLS-SL2S-ARCS strong lens candidates
- Short Name:
- J/ApJ/749/38
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present the Strong Lensing Legacy Survey-ARCS (SARCS) sample compiled from the final T0006 data release of the Canada-France-Hawaii Telescope Legacy Survey (CFHTLS) covering a total non-overlapping area of 159 deg^2^. We adopt a semi-automatic method to find gravitational arcs in the survey that makes use of an arc-finding algorithm. The candidate list is pruned by visual inspection and ranking to form the final SARCS sample. This list also includes some serendipitously discovered lens candidates which the automated algorithm did not detect. The SARCS sample consists of 127 lens candidates which span arc radii ~2"-18" within the unmasked area of ~150 deg^2^. Within the sample, 54 systems are promising lenses among which, we find 12 giant arcs (length-to-width ratio >= 8). We also find two radial arc candidates in SL2SJ141447+544704. From our sample, we detect a systematic alignment of the giant arcs with the major axis of the baryonic component of the putative lens in concordance with previous studies. This alignment is also observed for all arcs in the sample and does not vary significantly with increasing arc radius. The mean values of the photometric redshift distributions of lenses corresponding to the giant arcs and all arcs sample are at z~0.6.
- ID:
- ivo://CDS.VizieR/J/MNRAS/294/607
- Title:
- 7C(G) 151MHz survey of the Galactic plane
- Short Name:
- J/MNRAS/294/607
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Results form a survey of the northern Galactic plane (at declination >=30{deg} at 151MHz made with the Cambridge Low Frequency Synthesis Telescope are presented. This survey is designated 7C(G) - i.e. the Galactic portion of the ongoing 7C surveys. This covers the regions 80{deg}<l<104{deg} and 126{deg}<l<180{deg}, for |b|<=5.5{deg}, and has some coverage to |b|~9{deg}, with a resolution of ~70x70cosec{delta}arcsec^2^ (RAxDec). The observations, data reduction and calibration of this survey are described, and a catalogue of 6262 compact sources, with a completeness limit of ~0.25Jy over most of the survey region, is presented. The catalogue has an rms positional accuracy of better than 10arcsec, and the flux densities are tied to the scale of Roger, Bridle & Costain (1973AJ.....78.1030R) with an accuracy of better than 10 per cent.
- ID:
- ivo://nasa.heasarc/skyview/comptel
- Title:
- CGRO Compton Telescope: 3 channel data
- Short Name:
- Comptel
- Date:
- 07 Mar 2025
- Publisher:
- NASA/GSFC HEASARC
- Description:
- This survey is a maximum entropy solution to the data taken by the CompTel instrument on the <i> Compton </i> Gamma Ray Observatory. The data in this survey are intended only to give the general appearance of the MeV gamma-ray sky. Fluxes, flux limits and spectra should be derived using the Compass system for the analysis of CompTel data. Compass is available at the <a href="https://web.archive.org/web/20100622161007/http://wwwgro.unh.edu/comptel/compass/compass_users.html"> Compton Observatory Science Support Center </a>. <P> The maps were originally generated by the CompTel Instrument Team as three separate maps in the bands: <UL> <LI>1-3 MeV <LI>3-10 MeV <LI>10-30 MeV </ul> <P> All CompTel observations from phases 1, 2 and 3 were included in the maps (May 1991 through October 1994). These maps were combined into a single 3-D map at <i> SkyView </i> <P> Provenance: CompTel Instrument Team. Maps generated by Andrew Strong, Max-Planck Institute for Extraterrestrial Physics (Garching).. This is a service of NASA HEASARC.
- ID:
- ivo://CDS.VizieR/J/ApJS/178/339
- Title:
- ChaMP extended stellar survey (ChESS)
- Short Name:
- J/ApJS/178/339
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present 348 X-ray-emitting stars identified from correlating the Extended Chandra Multiwavelength Project (ChaMP), a wide-area serendipitous survey based on archival X-ray images, with the Sloan Digital Sky Survey (SDSS-DR6). We use morphological star/galaxy separation, matching to an SDSS quasar catalog, an optical color-magnitude cut, and X-ray data-quality tests to create our catalog, the ChaMP Extended Stellar Survey (ChESS), from a sample of 2121 matched ChaMP/SDSS sources. Our cuts retain 92% of the spectroscopically confirmed stars in the original sample while excluding 99.6% of the 684 spectroscopically confirmed extragalactic sources. Fewer than 3% of the sources in our final catalog are previously identified stellar X-ray emitters. For 42 catalog members, spectroscopic classifications are available in the literature. We present new spectral classifications and H{alpha} measurements for an additional 79 stars. The catalog is dominated by main-sequence stars; we estimate the fraction of giants in ChESS is ~10%. We identify seven giant stars (including a possible Cepheid and an RR Lyrae star) as ChaMP sources, as well as three cataclysmic variables. Future papers will present analyses of source variability and comparisons of this catalog to models of stellar activity in the Galactic disk.
- ID:
- ivo://CDS.VizieR/J/ApJS/150/19
- Title:
- ChaMP. I. First X-ray source catalog
- Short Name:
- J/ApJS/150/19
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The Chandra Multiwavelength Project (ChaMP) is a wide-area (~14deg^2^) survey of serendipitous Chandra X-ray sources, aiming to establish fair statistical samples covering a wide range of characteristics (such as absorbed active galactic nuclei, high-z clusters of galaxies) at flux levels (fX~10^-15^ to 10^-14^erg/s/cm^2^) ) intermediate between the Chandra deep surveys and previous missions. We present the first ChaMP catalog, which consists of 991 near on-axis, bright X-ray sources obtained from the initial sample of 62 observations. The data have been uniformly reduced and analyzed with techniques specifically developed for the ChaMP and then validated by visual examination. To assess source reliability and positional uncertainty, we perform a series of simulations and also use Chandra data to complement the simulation study. The false source detection rate is found to be as good as or better than expected for a given limiting threshold. On the other hand, the chance of missing a real source is rather complex, depending on the source counts, off-axis distance (or PSF), and background rate. The positional error (95% confidence level) is usually less than 1" for a bright source, regardless of its off-axis distance, while it can be as large as 4" for a weak source (~20counts) at a large off-axis distance (Doff-axis>8'). We have also developed new methods to find spatially extended or temporary variable sources, and those sources are listed in the catalog.
- ID:
- ivo://CDS.VizieR/J/ApJ/700/1702
- Title:
- ChaMPlane deep galactic bulge survey. I.
- Short Name:
- J/ApJ/700/1702
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We have carried out a deep X-ray and optical survey with Chandra and HST of low-extinction regions in the Galactic bulge. Here we present the results of a search for low-luminosity (L_X_<~10^34^erg/s) accreting binaries among the Chandra sources in the region closest to the Galactic center, at an angular offset of 1.4{deg}, that we have named the Limiting Window (LW). Based on their blue optical colors, excess H{alpha} fluxes, and high X-ray-to-optical flux ratios, we identify three likely accreting binaries; these are probably white dwarfs accreting from low-mass companions (cataclysmic variables; CVs) although we cannot exclude that they are quiescent neutron-star or black-hole low-mass X-ray binaries. Distance estimates put these systems farther than >~2kpc. Based on their H{alpha}-excess fluxes and/or high X-ray-to-optical flux ratios, we find 22 candidate accreting binaries; however, the properties of some can also be explained if they are dMe stars or active galaxies.
