- 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/ApJ/806/185
- Title:
- Strong-lensing systems from 4 surveys
- Short Name:
- J/ApJ/806/185
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- In this paper, we assemble a catalog of 118 strong gravitational lensing systems from the Sloan Lens ACS Survey (SLACS), BOSS emission-line lens survey (BELLS), Lens Structure and Dynamics (LSD), and Strong Lensing Legacy Survey (SL2S) and use them to constrain the cosmic equation of state. In particular, we consider two cases of dark energy phenomenology: the XCDM model, where dark energy is modeled by a fluid with constant w equation-of-state parameter, and in the Chevalier-Polarski-Linder (CPL) parameterization, where w is allowed to evolve with redshift, w(z)=w_0_+w_1_(z/1+z). We assume spherically symmetric mass distribution in lensing galaxies, but we relax the rigid assumption of the SIS model in favor of a more general power-law index {gamma}, also allowing it to evolve with redshifts {gamma}(z). Our results for the XCDM cosmology show agreement with values (concerning both w and {gamma} parameters) obtained by other authors. We go further and constrain the CPL parameters jointly with {gamma}(z). The resulting confidence regions for the parameters are much better than those obtained with a similar method in the past. They are also showing a trend of being complementary to the Type Ia supernova data. Our analysis demonstrates that strong gravitational lensing systems can be used to probe cosmological parameters like the cosmic equation of state for dark energy. Moreover, they have a potential to judge whether the cosmic equation of state evolved with time or not.
- ID:
- ivo://CDS.VizieR/J/ApJ/739/L44
- Title:
- Structural data for galaxies between 0.2<z<2.7
- Short Name:
- J/ApJ/739/L44
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present an analysis of the size growth seen in early-type galaxies over 10Gyr of cosmic time. Our analysis is based on a homogeneous synthesis of published data from 16 spectroscopic surveys observed at similar spatial resolution, augmented by new measurements for galaxies in the Gemini Deep Deep Survey. In total, our sample contains structural data for 465 galaxies (mainly early-type) in the redshift range 0.2<z<2.7. The size evolution of passively evolving galaxies over this redshift range is gradual and continuous, with no evidence for an end or change to the process around z~1, as has been hinted at by some surveys which analyze subsets of the data in isolation. The size growth appears to be independent of stellar mass, with the mass-normalized half-light radius scaling with redshift as R_e_{propto}(1+z)^-1.62+/-0.34^. Surprisingly, this power law seems to be in good agreement with the recently reported continuous size evolution of UV-bright galaxies in the redshift range z~0.5-3.5. It is also in accordance with the predictions from recent theoretical models.
- ID:
- ivo://CDS.VizieR/J/ApJS/203/24
- Title:
- Structural parameters of galaxies in CANDELS
- Short Name:
- J/ApJS/203/24
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present global structural parameter measurements of 109533 unique, H_F160W_-selected objects from the CANDELS multi-cycle treasury program. Sersic model fits for these objects are produced with GALFIT in all available near-infrared filters (H_F160W_, J_F125W_ and, for a subset, Y_F105W_). The parameters of the best-fitting Sersic models (total magnitude, half-light radius, Sersic index, axis ratio, and position angle) are made public, along with newly constructed point-spread functions for each field and filter. Random uncertainties in the measured parameters are estimated for each individual object based on a comparison between multiple, independent measurements of the same set of objects. To quantify systematic uncertainties, we create a mosaic with simulated galaxy images with a realistic distribution of input parameters and then process and analyze the mosaic in an identical manner as the real data.
- ID:
- ivo://CDS.VizieR/J/A+A/659/A59
- Title:
- Structural parameters of 389 local open clusters
- Short Name:
- J/A+A/659/A59
- Date:
- 07 Mar 2022 05:56:37
- Publisher:
- CDS
- Description:
- The distribution of member stars in the surroundings of an Open Cluster (OC) can shed light on the process of its formation, evolution and dissolution. The analysis of structural parameters of OCs as a function of their age and position in the Galaxy brings constraints on theoretical models of cluster evolution. The Gaia catalogue is very appropriate to find members of OCs at large distance from their centers. We aim at revisiting the membership lists of OCs from the solar vicinity, in particular by extending these membership lists to the peripheral areas thanks to Gaia EDR3. We then take advantage of these new lists of members to study the morphological properties and the mass segregation levels of the clusters. We used the clustering algorithm HDBSCAN on Gaia parallaxes and proper motions to systematically look for members up to 50pc from the cluster centers. We fitted a King's function on the radial density profile of these clusters and a Gaussian Mixture Model (GMM) on their two dimensional distribution of members to study their shape. We also evaluated the degree of mass segregation of the clusters and the correlations of these parameters with the age and Galactic position of the clusters. Our methodology performs well on 389 clusters out of the 467 selected ones, including several recently discovered clusters that were poorly studied until now. We report the detection of vast coronae around almost all the clusters and report the detection of 71 OCs with tidal tails, multiplying by more than four the number of such structures identified. We find the size of the cores to be on average smaller for old clusters than for young ones. Also, the overall size of the clusters seems to slightly increase with age while the fraction of stars in the halo seems to decrease. As expected the mass segregation is more pronounced in the oldest clusters but a clear trend with age is not seen. OCs are more extended than previously expected, regardless of their age. The decrease in the proportion of stars populating the clusters halos highlights the different cluster evaporation processes and the short timescales they need to affect the clusters. Reported parameters like cluster sizes or mass segregation levels all depend on cluster ages but can not be described as single functions of time.
- ID:
- ivo://CDS.VizieR/J/ApJ/799/95
- Title:
- Structure in 3D galaxy distribution. II. Voids
- Short Name:
- J/ApJ/799/95
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The major uncertainties in studies of the multi-scale structure of the universe arise not from observational errors but from the variety of legitimate definitions and detection methods for individual structures. To facilitate the study of these methodological dependencies, we have carried out 12 different analyses defining structures in various ways. This has been done in a purely geometrical way by utilizing the HOP (Eisenstein+, 1998ApJ...498..137E) algorithm as a unique parameter-free method of assigning groups of galaxies to local density maxima or minima. From three density estimation techniques (smoothing kernels, Bayesian blocks, and self-organizing maps) applied to three data sets (the Sloan Digital Sky Survey Data Release 7, the Millennium simulation, and randomly distributed points) we tabulate information that can be used to construct catalogs of structures connected to local density maxima and minima. We also introduce a void finder that utilizes a method to assemble Delaunay tetrahedra into connected structures and characterizes regions empty of galaxies in the source catalog.
- ID:
- ivo://CDS.VizieR/J/ApJ/889/80
- Title:
- STUDIES. III. SCUBA-2 450um gal. with MIPS & VLA obs.
- Short Name:
- J/ApJ/889/80
- Date:
- 11 Mar 2022
- Publisher:
- CDS
- Description:
- We construct a SCUBA-2 450{mu}m map in the COSMOS field that covers an area of 300arcmin^2^ and reaches a 1{sigma} noise level of 0.65mJy in the deepest region. We extract 256 sources detected at 450{mu}m with signal-to-noise ratios >4.0 and analyze the physical properties of their multiwavelength counterparts. We find that most of the sources are at z<~3, with a median of z=1.79_-0.15_^+0.03^%. About 35_-25_^+32^% of our sources are classified as starburst galaxies based on their total star formation rates (SFRs) and stellar masses (M_*_). By fitting the far-infrared spectral energy distributions, we find that our 450{mu}m selected sample has a wide range of dust temperatures (20K<~T_d_<~60K), with a median of T_d_=38.3_-0.9_^+0.4^K. We do not find a redshift evolution in dust temperature for sources with L_IR_>10^12^L_{sun}_ at z<3. However, we find a moderate correlation where the dust temperature increases with the deviation from the SFR-M_*_ relation. The increase in dust temperature also correlates with optical morphology, which is consistent with merger-triggered starbursts in submillimeter galaxies. Our galaxies do not show the tight IRX-{beta}_UV_ correlation that has been observed in the local universe. We construct the infrared luminosity functions of our 450{mu}m sources and measure their comoving SFR densities (SFRDs). The contribution of the L_IR_>10^12^L_{sun}_ population to the SFRD rises dramatically from z=0 to 2 ({propto}(1+z)^3.9+/-1.1^) and dominates the total SFRD at z>~2.
- ID:
- ivo://CDS.VizieR/J/ApJ/865/103
- Title:
- STUDIES. II. NIR morphologies of submm galaxies
- Short Name:
- J/ApJ/865/103
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present structural parameters and morphological properties of faint 450{mu}m selected submillimeter galaxies (SMGs) from the JCMT Large Program, STUDIES, in the COSMOS-CANDELS region. Their properties are compared to an 850{mu}m selected and a matched star-forming samples. We investigate stellar structures of 169 faint 450{mu}m sources (S_450_=2.8-29.6mJy; S/N>4) at z<3 using HST near-infrared observations. Based on our spectral energy distribution fitting, half of such faint SMGs (L_IR_=10^11.65^+/-0.98^L_{sun}_) lie above the star formation rate (SFR)/stellar mass plane. The size-mass relation shows that these SMGs are generally similar to less-luminous star-forming galaxies selected by NUV-r versus r-J colors. Because of the intrinsic luminosity of the sample, their rest-frame optical emission is less extended than the 850{mu}m sources (S_850_>2mJy) and more extended than the star-forming galaxies in the same redshift range. For the stellar mass and SFR-matched sample at z~1 and z~2, the size differences are marginal between faint SMGs and the matched galaxies. Moreover, faint SMGs have similar Sersic indices and projected axis ratios as star-forming galaxies with the same stellar mass and SFR. Both SMGs and the matched galaxies show high fractions (~70%) of disturbed features at z~2, and the fractions depend on the SFRs. These suggest that their star formation activity is related to galaxy merging and the stellar structures of SMGs are similar to those of star-forming galaxies. We show that the depths of submillimeter surveys are approaching the lower luminosity end of star-forming galaxies, allowing us to detect galaxies on the main sequence.
- ID:
- ivo://CDS.VizieR/J/MNRAS/421/3060
- Title:
- Subaru/XMM Deep Field radio imaging. III.
- Short Name:
- J/MNRAS/421/3060
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present spectroscopic and 11-band photometric redshifts for galaxies in the 100-uJy Subaru/XMM-Newton Deep Field radio source sample. We find good agreement between our redshift distribution and that predicted by the Square Kilometre Array (SKA) Simulated Skies project. We find no correlation between K-band magnitude and radio flux, but show that sources with 1.4-GHz flux densities below ~1mJy are fainter in the near-infrared than brighter radio sources at the same redshift, and we discuss the implications of this result for spectroscopically incomplete samples where the K-z relation has been used to estimate redshifts. We use the infrared-radio correlation to separate our sample into radio-loud and radio-quiet objects and show that only radio-loud hosts have spectral energy distributions consistent with predominantly old stellar populations, although the fraction of objects displaying such properties is a decreasing function of radio luminosity.
- ID:
- ivo://CDS.VizieR/J/A+A/616/A107
- Title:
- (Sub)millimeter RRL in high-mass star-forming clumps
- Short Name:
- J/A+A/616/A107
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Previous radio recombination line (RRL) observations of dust clumps identified in the APEX Telescope Large Area Survey of the Galaxy (ATLASGAL) have led to the detection of a large number of RRLs in the 3mm range. Here, we aim to study their excitation with shorter wavelength (sub)millimeter radio recombination line (submm-RRL) observations. We made observations of submm-RRLs with low principal quantum numbers (n<=30) using the APEX 12m telescope, toward 104 HII regions associated with massive dust clumps from ATLASGAL. The observations covered the H25{alpha}, H28{alpha}, and H35{beta} transitions. Toward a small subsample the H26{alpha}, H27{alpha}, H29{alpha}, and H30{alpha} lines were observed to avoid contamination by molecular lines at adjacent frequencies. We have detected submm-RRLs (signal-to-noise >=3{sigma}) from compact HII regions embedded within 93 clumps. The submm-RRLs are approximately a factor of two brighter than the mm-RRLs and consistent with optically thin emission in local thermodynamic equilibrium (LTE). The average ratio (0.31) of the measured H35{beta}/H28{alpha} fluxes is close to the LTE value of 0.28. No indication of RRL maser emission has been found. The Lyman photon flux, bolometric, and submm-RRL luminosities toward the submm-RRL detected sources present significant correlations. The trends of dust temperature and the ratio of bolometric luminosity to clump mass, L_bol_/M_clump_, indicate that the HII regions are related to L_bol_/M_clump_, indicate that the HII regions are related to the most massive and luminous clumps. By estimating the production rate of ionizing photons, Q, from the submm-RRL flux, we find that the Q(H28{alpha}) measurements provide estimates of the Lyman continuum photon flux consistent with those determined from 5GHz radio continuum emission. Six RRL sources show line profiles that are a combination of a narrow and a broad Gaussian feature. The broad features are likely associated with high-velocity ionized flows. We have detected submm-RRLs toward 93 ATLASGAL clumps. Six RRL sources have high-velocity RRL components likely driven by high-velocity ionized flows. Their observed properties are consistent with thermal emission that correlates well with the Lyman continuum flux of the HII regions. The sample of HII regions with mm/submm-RRL detections probes, in our Galaxy, luminous clumps (L_bol_>10^4^L_{sun}_) with high L_bol_/M_clump_. We also provide suitable candidates for further studies of the morphology and kinematics of embedded, compact HII regions with the Atacama Large Millimeter/submillimeter Array (ALMA).
