- ID:
- ivo://CDS.VizieR/J/ApJS/224/11
- Title:
- SHELS: redshift survey of the F1 DLS field
- Short Name:
- J/ApJS/224/11
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The Smithsonian Hectospec Lensing Survey (SHELS) is a complete redshift survey covering two well-separated fields (F1 and F2) of the Deep Lens Survey (DLS). Both fields are more than 94% complete to a Galactic extinction corrected R_0_=20.2. Here, we describe the redshift survey of the F1 field centered at RA=00:53:25.3 and DEC=12:33:55 (J2000); like F2, the F1 field covers ~4deg^2^. The redshift survey of the F1 field includes 9426 new galaxy redshifts measured with Hectospec on the MMT (published here). As a guide to future uses of the combined survey, we compare the mass metallicity relation and the distributions of D_n_4000 as a function of stellar mass and redshift for the two fields. The mass-metallicity relations differ by an insignificant 1.6{sigma}. For galaxies in the stellar mass range 10^10^-10^11^M_{sun}_, the increase in the star-forming fraction with redshift is remarkably similar in the two fields. The seemingly surprising 31%-38% difference in the overall galaxy counts in F1 and F2 is probably consistent with the expected cosmic variance given the subtleties of the relative systematics in the two surveys. We also review the DLS cluster detections in the two fields: poorer photometric data for F1 precluded secure detection of the single massive cluster at z=0.35 that we find in SHELS. Taken together, the two fields include 16055 redshifts for galaxies with R_0_<=20.2 and 20754 redshifts for galaxies with R<=20.6. These dense surveys in two well-separated fields provide a basis for future investigations of galaxy properties and large-scale structure.
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Search Results
- ID:
- ivo://CDS.VizieR/J/ApJ/510/659
- Title:
- Size and Structure of AGN in NGC 5548
- Short Name:
- J/ApJ/510/659
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present the results of 3 yr of ground-based observations of the Seyfert 1 galaxy NGC 5548, which, combined with previously reported data, yield optical continuum and broad-line H{beta} light curves for a total of 8 yr. The light curves consist of over 800 points, with a typical spacing of a few days between observations. During this 8 yr period, the nuclear continuum has varied by more than a factor of 7, and the H{beta} emission line has varied by a factor of nearly 6. The H{beta} emission line responds to continuum variations with a time delay or lag of {=~}10--20 days, the precise value varying somewhat from year to year. We find some indications that the lag varies with continuum flux in the sense that the lag is larger when the source is brighter.
- ID:
- ivo://CDS.VizieR/J/ApJ/851/48
- Title:
- SLACS. XIII. Galaxy-scale strong lens candidates
- Short Name:
- J/ApJ/851/48
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present the full sample of 118 galaxy-scale strong-lens candidates in the Sloan Lens ACS (SLACS) Survey for the Masses (S4TM) Survey, which are spectroscopically selected from the final data release of the Sloan Digital Sky Survey. Follow-up Hubble Space Telescope (HST) imaging observations confirm that 40 candidates are definite strong lenses with multiple lensed images. The foreground-lens galaxies are found to be early-type galaxies (ETGs) at redshifts 0.06-0.44, and background sources are emission-line galaxies at redshifts 0.22-1.29. As an extension of the SLACS Survey, the S4TM Survey is the first attempt to preferentially search for strong-lens systems with relatively lower lens masses than those in the pre-existing strong-lens samples. By fitting HST data with a singular isothermal ellipsoid model, we find that the total projected mass within the Einstein radius of the S4TM strong-lens sample ranges from 3x10^10^M_{sun}_ to 2x10^11^M_{sun}_. In Shu+ (2015ApJ...803...71S), we have derived the total stellar mass of the S4TM lenses to be 5x10^10^M_{sun}_ to 1x10^12^M_{sun}_. Both the total enclosed mass and stellar mass of the S4TM lenses are on average almost a factor of 2 smaller than those of the SLACS lenses, which also represent the typical mass scales of the current strong-lens samples. The extended mass coverage provided by the S4TM sample can enable a direct test, with the aid of strong lensing, for transitions in scaling relations, kinematic properties, mass structure, and dark-matter content trends of ETGs at intermediate-mass scales as noted in previous studies.
- ID:
- ivo://CDS.VizieR/J/ApJ/777/97
- Title:
- SL2S galaxy-scale lens sample. III.
- Short Name:
- J/ApJ/777/97
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present Hubble Space Telescope (HST) imaging data and Canada-France-Hawaii Telescope (CFHT) near-infrared ground-based images for the final sample of 56 candidate galaxy-scale lenses uncovered in the CFHT Legacy Survey as part of the Strong Lensing in the Legacy Survey (SL2S) project. The new images are used to perform lens modeling, measure surface photometry, and estimate stellar masses of the deflector early-type galaxies (ETGs). Lens modeling is performed on the HST images (or CFHT when HST is not available) by fitting the spatially extended light distribution of the lensed features assuming a singular isothermal ellipsoid mass profile and by reconstructing the intrinsic source light distribution on a pixelized grid. Based on the analysis of systematic uncertainties and comparison with inference based on different methods, we estimate that our Einstein radii are accurate to ~3%. HST imaging provides a much higher success rate in confirming gravitational lenses and measuring their Einstein radii than CFHT imaging does. Lens modeling with ground-based images, however, when successful, yields Einstein radius measurements that are competitive with space-based images. Information from the lens models is used together with spectroscopic information from companion Paper IV (2013ApJ...777...98S) to classify the systems, resulting in a final sample of 39 confirmed (grade A) lenses and 17 promising candidates (grade B,C).
- ID:
- ivo://CDS.VizieR/J/ApJ/785/144
- Title:
- SL2S galaxy-scale sample of lens candidates
- Short Name:
- J/ApJ/785/144
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present RINGFINDER, a tool for finding galaxy-scale strong gravitational lenses in multi-band imaging data. By construction, the method is sensitive to configurations involving a massive foreground ETG and a faint, background, blue source. RINGFINDER detects the presence of blue residuals embedded in an otherwise smooth red light distribution by difference imaging in two bands. The method is automated for efficient application to current and future surveys, having originally been designed for the 150 deg^2^ Canada-France-Hawaii Telescope Legacy Survey (CFHTLS). We describe each of the steps of RINGFINDER. We then carry out extensive simulations to assess completeness and purity. For sources with magnification {mu}>4, RINGFINDER reaches 42% (25%) completeness and 29% (86%) purity before (after) visual inspection. The completeness of RINGFINDER is substantially improved in the particular range of Einstein radii 0.8"<=R_Ein_<=2.0" and lensed images brighter than g=22.5, where it can be as high as ~70%. RINGFINDER does not introduce any significant bias in the source or deflector population. We conclude by presenting the final catalog of RINGFINDER CFHTLS galaxy-scale strong lens candidates. Additional information obtained with Hubble Space Telescope and Keck adaptive optics high-resolution imaging, and with Keck and Very Large Telescope spectroscopy, is used to assess the validity of our classification and measure the redshift of the foreground and the background objects. From an initial sample of 640000 ETGs, RINGFINDER returns 2500 candidates, which we further reduce by visual inspection to 330 candidates. We confirm 33 new gravitational lenses from the main sample of candidates, plus an additional 16 systems taken from earlier versions of RINGFINDER. First applications are presented in the Strong Lensing Legacy Survey galaxy-scale lens sample paper series.
- ID:
- ivo://CDS.VizieR/J/MNRAS/428/389
- Title:
- SLUGGS globular clusters in early-type galaxies
- Short Name:
- J/MNRAS/428/389
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present a spectrophotometric survey of 2522 extragalactic globular clusters (GCs) around 12 early-type galaxies, nine of which have not been published previously. Combining space-based and multicolour wide-field ground-based imaging, with spectra from the Keck/DEep Imaging Multi-Object Spectrograph (DEIMOS) instrument, we obtain an average of 160 GC radial velocities per galaxy, with a high-velocity precision of ~15km/s per GC. After studying the photometric properties of the GC systems, such as their spatial and colour distributions, we focus on the kinematics of metal-poor (blue) and metal-rich (red) GC subpopulations to an average distance of ~8 effective radii from the galaxy centre.
- ID:
- ivo://CDS.VizieR/J/MNRAS/458/105
- Title:
- SLUGGS NGC 3607 and 3608 globular clusters
- Short Name:
- J/MNRAS/458/105
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present an investigation of the globular cluster (GC) systems of NGC 3607 and NGC 3608 as part of the ongoing SLUGGS (SAGES Legacy Unifying Globulars and GalaxieS) survey. We use wide-field imaging data from the Subaru telescope in the g, r and i filters to analyse the radial density, colour and azimuthal distributions of both GC systems. With the complementary kinematic data obtained from the Keck II telescope, we measure the radial velocities of a total of 81 GCs. Our results show that the GC systems of NGC 3607 and NGC 3608 have a detectable spatial extent of ~15 and 13 galaxy effective radii, respectively. Both GC systems show a clear bimodal colour distribution. We detect a significant radial colour gradient for the GC subpopulations in both galaxies. NGC 3607 exhibits an overabundance of red GCs on the galaxy minor axis and NGC 3608 shows a misalignment in the GC subpopulation position angles with respect to the galaxy stellar component. With the aid of literature data, we discuss several relationships between the properties of GC systems and their host galaxies. A one-to-one relation between the ellipticities of red GCs and the galaxy stellar light emphasizes the evolutionary similarities between them. In our sample of four slowly rotating galaxies with kinematically decoupled cores, we observe a higher ellipticity for the blue GC subpopulation than their red counterparts. Also, we notice the flattening of negative colour gradients for the blue GC subpopulations with increasing galaxy stellar mass. Finally, we discuss the formation scenarios associated with the blue GC subpopulation.
- ID:
- ivo://CDS.VizieR/J/ApJS/240/1
- Title:
- SMUDGes. I. First results in the Coma Cluster
- Short Name:
- J/ApJS/240/1
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present a homogeneous catalog of 275 large (effective radius >~5.3") ultra-diffuse galaxy (UDG) candidates lying within an ~290deg^2^ region surrounding the Coma Cluster. The catalog results from our automated postprocessing of data from the Legacy Surveys, a three-band imaging survey covering 14000deg^2^ of the extragalactic sky. We describe a pipeline that identifies UDGs and provides their basic parameters. The survey is as complete in these large UDGs as previously published UDG surveys of the central region of the Coma Cluster. We conclude that the majority of our detections are at roughly the distance of the Coma Cluster, implying effective radii >=2.5kpc, and that our sample contains a significant number of analogs of DF44 (SMDG1300580+265835), where the effective radius exceeds 4kpc, both within the cluster and in the surrounding field. The g-z color of our UDGs spans a large range, suggesting that even large UDGs may reflect a range of formation histories. A majority of the UDGs are consistent with being lower stellar mass analogs of red sequence galaxies, but we find both red and blue UDG candidates in the vicinity of the Coma Cluster and a relative overabundance of blue UDG candidates in the lower-density environments and the field. Our eventual processing of the full Legacy Surveys data will produce the largest, most homogeneous sample of large UDGs.
- ID:
- ivo://CDS.VizieR/J/ApJ/740/92
- Title:
- SN.Ia host galaxies properties
- Short Name:
- J/ApJ/740/92
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We improve estimates of the stellar mass and mass-weighted average age of Type Ia supernova (SN Ia) host galaxies by combining UV and near-IR photometry with optical photometry in our analysis. Using 206 SNe Ia drawn from the full three-year Sloan Digital Sky Survey (SDSS-II) Supernova Survey and multi-wavelength host-galaxy photometry from SDSS, the Galaxy Evolution Explorer, and the United Kingdom Infrared Telescope Infrared Deep Sky Survey, we present evidence of a correlation (1.9{sigma} confidence level) between the residuals of SNe Ia about the best-fit Hubble relation and the mass-weighted average age of their host galaxies. The trend is such that older galaxies host SNe Ia that are brighter than average after standard light-curve corrections are made. We also confirm, at the 3.0{sigma} level, the trend seen by previous studies that more massive galaxies often host brighter SNe Ia after light-curve correction.
- ID:
- ivo://CDS.VizieR/J/ApJ/755/61
- Title:
- SN Ia host galaxies SFR from SDSS-II
- Short Name:
- J/ApJ/755/61
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Using data from the Sloan Digital Sky Supernova Survey-II (SDSS-II SN Survey, Frieman et al., 2008AJ....135..338F), we measure the rate of Type Ia supernovae (SNe Ia) as a function of galaxy properties at intermediate redshift. A sample of 342 SNe Ia with 0.05<z<0.25 is constructed. Using broadband photometry and redshifts, we use the P\'EGASE.2 spectral energy distributions to estimate host galaxy stellar masses and recent star formation rates (SFRs).