171 research outputs found

    Modeling Software Characteristics and Their Correlations in A Specific Domain by Comparing Existing Similar Systems

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    QSIC 2005, Melbourne, Australia, Sep. 2005Software in a specific domain has several characteristics and each characteristic should be fixed when the software requirements are specified. In addition, these characteristics sometimes correlate with each other. However, we sometimes forget to specify several characteristics and/or to take their correlations into account during requirements elicitation. In this paper, we propose a meta-model for representing such characteristics and their correlations, and also propose a method to build a model for a specific domain by using documents about existing software systems. By using our model for a domain, a requirements specification for a system in the domain could be complete and unambiguous because requirements analysts can check the characteristics that should be decided. The specification could be also correct and consistent because the analysts can know side effects of a requirement change by using correlation among the characteristics. We have applied our methods to a case study for confirming the usefulness of such model and the methods.ArticleProceedings : the Fifth International Conference on Quality Software. 215-222 (2005)conference pape

    COOL-LAMPS III: Discovery of a 25".9 Separation Quasar Lensed by a Merging Galaxy Cluster

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    In the third paper from the COOL-LAMPS Collaboration, we report the discovery of COOL J0542-2125, a gravitationally lensed quasar at z=1.84z=1.84, observed as three images due to an intervening massive galaxy cluster at z=0.61z=0.61. The lensed quasar images were identified in a search for lens systems in recent public optical imaging data and have separations on the sky up to 25".9, wider than any previously known lensed quasar. The galaxy cluster acting as a strong lens appears to be in the process of merging, with two sub-clusters separated by ∌1\sim 1 Mpc in the plane of the sky, and their central galaxies showing a radial velocity difference of ∌1000\sim 1000 km/s. Both cluster cores show strongly lensed images of an assortment of background sources, as does the region between them. A preliminary strong lens model implies masses of $M(<250\ \rm{kpc}) = 1.79^{+0.16} _{-0.01} \times 10^{14} M_{\odot}and and M(<250\ \rm{kpc}) = 1.48^{+0.04}_{-0.10} \times 10^{14} M_{\odot}$ for the East and West sub-clusters, respectively. This line of sight is also coincident with a ROSAT ALL-sky Survey source, centered between the two confirmed cluster halos reminiscent of other major cluster-scale mergers.Comment: 13 pages, 6 figures. Submitted to Ap

    COOL-LAMPS. IV. A Sample of Bright Strongly Lensed Galaxies at 3 < z < 4

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    We report the discovery of five bright, strong gravitationally lensed galaxies at 3 < z < 4: COOL J0101+2055 (z = 3.459), COOL J0104−0757 (z = 3.480), COOL J0145+1018 (z = 3.310), COOL J0516−2208 (z = 3.549), and COOL J1356+0339 (z = 3.753). These galaxies have magnitudes of rAB, zAB < 21.81 mag and are lensed by galaxy clusters at 0.26 < z < 1. This sample nearly doubles the number of known bright lensed galaxies with extended arcs at 3 < z < 4. We characterize the lensed galaxies using ground-based grz/giy imaging and optical spectroscopy. We report model-based magnitudes and derive stellar masses, dust content, and star formation rates via stellar population synthesis modeling. Building lens models based on ground-based imaging, we estimate source magnifications ranging from ∌29 to ∌180. Combining these analyses, we derive demagnified stellar masses in the range log10(M∗/M⊙)∌9.69−10.75{\mathrm{log}}_{10}({M}_{* }/{M}_{\odot })\sim 9.69-10.75 and star formation rates in the youngest age bin in the range log10(SFR/(M⊙ yr−1))∌0.39−1.46{\mathrm{log}}_{10}(\mathrm{SFR}/({M}_{\odot }\,{\mathrm{yr}}^{-1}))\sim 0.39-1.46, placing the sample galaxies on the massive end of the star-forming main sequence in this redshift interval. In addition, three of the five galaxies have strong Lyα emissions, offering unique opportunities to study Lyα emitters at high redshift in future work

    COOL-LAMPS VI: Lens model and New Constraints on the Properties of COOL J1241+2219, a Bright z = 5 Lyman Break Galaxy and its z = 1 Cluster Lens

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    We present a strong lensing analysis of COOL J1241+2219, the brightest known gravitationally lensed galaxy at z≄5z \geq 5, based on new multi-band Hubble Space Telescope (HST) imaging data. The lensed galaxy has a redshift of z=5.043, placing it shortly after the end of the Epoch of Reionization, and an AB magnitude z_AB=20.47 mag (Khullar et al. 2021). As such, it serves as a touchstone for future research of that epoch. The high spatial resolution of HST reveals internal structure in the giant arc, from which we identify 15 constraints and construct a robust lens model. We use the lens model to extract cluster mass and lensing magnification. We find that the mass enclosed within the Einstein radius of the z=1.001 cluster lens is M(<5.77'')=1.079−0.007+0.0231.079^{+0.023}_{-0.007}, significantly lower than other known strong lensing clusters at its redshift. The average magnification of the giant arc is =76−20+40=76^{+40}_{-20}, a factor of 2.4−0.7+1.42.4^{+1.4}_{-0.7} greater than previously estimated from ground-based data; the flux-weighted average magnification is =92−31+37=92^{+37}_{-31} We update the current measurements of the stellar mass and star formation rate (SFR) of the source for the revised magnification, log⁥(M⋆/M⊙)=9.7±0.3\log(M_\star/M_{\odot})=9.7\pm0.3 and SFR=10.3−4.4+7.0{\rm SFR} = 10.3^{+7.0}_{-4.4} M⊙ M_{\odot} yr−1^{-1}. The powerful lensing magnification acting upon COOL J1241+2219 resolves the source and enables future studies of the properties of its star formation on a clump-by-clump basis. The lensing analysis presented here will support upcoming multiwavelength characterization with HST and JWST data of the stellar mass assembly and physical properties of this high-redshift lensed galaxy.Comment: Submitted to Ap

    COOL-LAMPS. VI. Lens Model and New Constraints on the Properties of COOL J1241+2219, a Bright z = 5 Lyman Break Galaxy and its z = 1 Cluster Lens

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    We present a strong lensing analysis of COOL J1241+2219, the brightest known gravitationally lensed galaxy at z ≄ 5, based on new multiband Hubble Space Telescope (HST) imaging data. The lensed galaxy has a redshift of z = 5.043, placing it shortly after the end of the “Epoch of Reionization,” and an AB magnitude z AB = 20.47 mag (Khullar et al.). As such, it serves as a touchstone for future research of that epoch. The high spatial resolution of HST reveals internal structure in the giant arc, from which we identify 15 constraints and construct a robust lens model. We use the lens model to extract the cluster mass and lensing magnification. We find that the mass enclosed within the Einstein radius of the z = 1.001 cluster lens is M(<5.″77)=1.079−0.007+0.023×1013M☉ , significantly lower than other known strong lensing clusters at its redshift. The average magnification of the giant arc is ă€ˆÎŒ arc〉 = 76−20+40 , a factor of 2.4−0.7+1.4 greater than previously estimated from ground-based data; the flux-weighted average magnification is ă€ˆÎŒ arc〉 = 92−31+37 . We update the current measurements of the stellar mass and star formation rate (SFR) of the source for the revised magnification to log(M⋆/M⊙)= 9.7 ± 0.3 and SFR = 10.3−4.4+7.0 M ⊙ yr−1, respectively. The powerful lensing magnification acting upon COOL J1241+2219 resolves the source and enables future studies of the properties of its star formation on a clump-by-clump basis. The lensing analysis presented here will support upcoming multiwavelength characterization with HST and JWST data of the stellar mass assembly and physical properties of this high-redshift lensed galaxy

    COOL-LAMPS. VII. Quantifying Strong-lens Scaling Relations with 177 Cluster-scale Gravitational Lenses in DECaLS

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    We compute parametric measurements of the Einstein-radius-enclosed total mass for 177 cluster-scale strong gravitational lenses identified by the ChicagO Optically-selected Lenses Located At the Margins of Public Surveys (COOL-LAMPS) collaboration with lens redshifts ranging from 0.2âȘ…zâȘ…1.00.2 \lessapprox z \lessapprox 1.0 using only two measured parameters in each lensing system: the Einstein radius, and the brightest-cluster-galaxy (BCG) redshift. We then constrain the Einstein-radius-enclosed luminosity and stellar mass by fitting parametric spectral energy distributions (SEDs) with aperture photometry from the Dark Energy Camera Legacy Survey (DECaLS) in the gg, rr, and zz-band Dark Energy Camera (DECam) filters. We find that the BCG redshift, enclosed total mass, and enclosed luminosity are strongly correlated and well described by a planar relationship in 3D space. We also find that the enclosed total mass and stellar mass are correlated with a logarithmic slope of 0.443±0.0350.443\pm0.035, and the enclosed total mass and stellar-to-total mass fraction are correlated with a logarithmic slope of −0.563±0.035-0.563\pm0.035. The correlations described here can be used to validate strong lensing candidates in upcoming imaging surveys -- such as Rubin/Legacy Survey of Space and Time (LSST) -- in which an algorithmic treatment of lensing systems will be needed due to the sheer volume of data these surveys will produce.Comment: 17 pages, 5 figures, 2 tables. Submitted to The Astrophysical Journal. v3: updated authors, formatting, grammar, and reference
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