Examinando por Autor "Lin, H."

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    DES meets Gaia: Discovery of strongly lensed quasars from a multiplet search
    (Oxford University Press, 2018-10) Agnello, A.; Lin, H.; Kuropatkin, N.; Buckley-Geer, E.; Anguita, T.; Schechter, P.L.; Morishita, T.; Motta, V.; Rojas, K.; Treu, T.; Amara, A.; Auger, M.W.; Courbin, F.; Fassnacht, C.D.; Frieman, J.; More, A.; Marshall, P.J.; McMahon, R.G.; Meylan, G.; Suyu, S.H.; Glazebrook, K.; Morgan, N.; Nord, B.; Abbott, T.M.C.; Abdalla, F.B.; Annis, J.; Bechtol, K.; Benoit-Lévy, K.; Bertin, E.; Bernstein, R.A.; Brooks, D.; Burke, D.L.; Carnero Rosell, A.; Carretero, J.; Cunha, C.E.; D'Andrea, C.B.; da Costa, L.N.; Desai, S.; Drlica-Wagner, A.; Eifler, T.F.; Flaugher, B.; García-Bellido, J.; Gaztanaga, E.; Gerdes, D.W.; Gruen, D.; Gruendl, R.A.; Gschwend, J.; Gutierrez, G.; Honscheid, K.; James, D.J.; Kuehn, K.; Lahav, O.; Lima, M.; Maia, M.A.G.; March, M.; Menanteau, F.; Miquel, R.; Ogando, R.L.C.; Plazas, A.A.; Sanchez, E.; Scarpine, V.; Schindler, R.; Schubnell, M.; Sevilla-Noarbe, I.; Smith, M.; Soares-Santos, M.; Sobreira, F.; Suchyta, E.; Swanson, M.E.C.; Tarle, G.; Tucker, D.; Wechsler, R.
    We report the discovery, spectroscopic confirmation, and first lens models of the first, strongly lensed quasars from a combined search in WISE and Gaia-DR1 over the DES footprint. Their Einstein radii span a range between ≈2.0 arcsec and ≈0.4 arcsec. Two of these (WGD2038-4008, RA = 20:38:02.65, Dec.=-40:08:14.64; WGD2021-4115, RA = 20:21:39.45, Dec. = -41:15:57.11) also have confirmed deflector redshifts. The four-image lens WGD2038-4008, with source and deflector redshifts s = 0.777 ± 0.001 and zl = 0.230 ± 0.002, respectively, has a deflector with radius Reff ≈ 3.4 arcsec, stellar mass log(M*/M⊙) = 11.64+0.20 -0.43, and extended isophotal shape variation. Simple lens models yield Einstein radii RE = (1.30 ± 0.04) arcsec, axis ratio q = 0.75 ± 0.1 (compatible with that of the starlight) and considerable shear-ellipticity degeneracies. The two-image lens WGD2021-4115 has zs = 1.390 ± 0.001 and zl = 0.335 ± 0.002, and Einstein radius RE = (1.1 ± 0.1) arcsec, but higher-resolution imaging is needed to accurately separate the deflector and faint quasar image. Analogous lens model degeneracies hold for the other six lenses (J0146-1133, J0150-4041, J0235-2433, J0245-0556, J0259-2338, and J0508-2748) shown in this paper. © 2018 The Author(s) Published by Oxford University Press on behalf of the Royal Astronomical Society.
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    Forbidden hugs in pandemic times: III. Observations of the luminous red nova AT 2021biy in the nearby galaxy NGC 4631
    (EDP Sciences, 2022-11-01) Cai, Y.-Z.; Pastorello, A.; Fraser, M.; Wang, X.-F.; Filippenko, A.V.; Reguitti, A.; Patra, K.C.; Goranskij, V.P.; Barsukova, E.A.; Brink, T.G.; Elias-Rosa, N.; Stevance, H.F.; Zheng, W.; Yang, Y.; Atapin, K.E.; Benetti, S.; De Boer, T.J.L.; Bose, S.; Burke, J.; Byrne, R.; Cappellaro, E.; Chambers, K.C.; Chen, W.-L.; Emami, N.; Gao, H.; Hiramatsu, D.; Howell, D.A.; Huber, M.E.; Kankare, E.; Kelly, P.L.; Kotak, R.; Kravtsov, T.; Lander, V. Yu.; Li, Z.-T.; Lin, C.-C.; Lundqvist, P.; Magnier, E.A.; Malygin, E.A.; Maslennikova, N.A.; Matilainen, K.; Mazzali, P.A.; Mccully, C.; Mo, J.; Moran, S.; Newsome, M.; Oparin, D.V.; Padilla Gonzalez, E.; Reynolds, T.M.; Shatsky, N.I.; Smartt, S.J.; Smith, K.W.; Stritzinger, M.D.; Tatarnikov, A.M.; Terreran, G.; Uklein, R.I.; Valerin, G.; Vallely, P.J.; Vozyakova, O.V.; Wainscoat, R.; Yan, S.-Y.; Zhang, J.-J.; Zhang, T.-M.; Zheltoukhov, S.G.; Dastidar, R.; Fulton, M.; Galbany, L.; Gangopadhyay, A.; Ge, H.-W.; Gutiérrez, C.P.; Lin, H.; Misra, K.; Ou, Z.-W.; Salmaso, I.; Tartaglia, L.; Xiao, L.; Zhang, X.-H.
    We present an observational study of the luminous red nova (LRN) AT 2021biy in the nearby galaxy NGC 4631. The field of the object was routinely imaged during the pre-eruptive stage by synoptic surveys, but the transient was detected only at a few epochs from ∼231 days before maximum brightness. The LRN outburst was monitored with unprecedented cadence both photometrically and spectroscopically. AT 2021biy shows a short-duration blue peak, with a bolometric luminosity of ∼1.6×1041 erg s-1, followed by the longest plateau among LRNe to date, with a duration of 210 days. A late-time hump in the light curve was also observed, possibly produced by a shell-shell collision. AT 2021biy exhibits the typical spectral evolution of LRNe. Early-time spectra are characterised by a blue continuum and prominent H emission lines. Then, the continuum becomes redder, resembling that of a K-type star with a forest of metal absorption lines during the plateau phase. Finally, late-time spectra show a very red continuum (TBB ≈ 2050 K) with molecular features (e.g., TiO) resembling those of M-type stars. Spectropolarimetric analysis indicates that AT 2021biy has local dust properties similar to those of V838 Mon in the Milky Way Galaxy. Inspection of archival Hubble Space Telescope data taken on 2003 August 3 reveals a ∼20 M⊗ progenitor candidate with log (L/L⊗) = 5.0 dex and Teff 5900 K at solar metallicity. The above luminosity and colour match those of a luminous yellow supergiant. Most likely, this source is a close binary, with a 17-24 M⊗ primary component. © Y.-Z. Cai et al. 2022.
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    SOAR/Goodman Spectroscopic Assessment of Candidate Counterparts of the LIGO/Virgo Event GW190814
    (IOP Publishing Ltd, 2022-04-01) Tucker, D.L.; Wiesner, M.P.; Allam, S.S.; Soares-Santos, M.; Bom, C.R.; Butner, M.; Garcia, A.; Morgan, R.; Olivares, E. F.; Palmese, A.; Santana-Silva, L.; Shrivastava, A.; Annis, J.; García-Bellido, J.; Gill, M.S.S.; Herner, K.; Kilpatrick, C.D.; Makler, M.; Sherman, N.; Amara, A.; Lin, H.; Smith, M.; Swann, E.; Arcavi, I.; Bachmann, T.G.; Bechtol, K.; Berlfein, F.; Briceño, C.; Brout, D.; Butler, R.E.; Cartier, R.; Casares, J.; Chen, H.-Y.; Conselice, C.; Contreras, C.; Cook, E.; Cooke, J.; Dage, K.; D'Andrea, C.; Davis, T.M.; De Carvalho, R.; Diehl, H.T.; Dietrich, J.P.; Doctor, Z.; Drlica-Wagner, A.; Drout, M.; Farr, B.; Finley, D.A.; Fishbach, M.; Foley, R.J.; Förster-Burón, F.; Fosalba, P.; Friedel, D.; Frieman, J.; Frohmaier, C.; Gruendl, R.A.; Hartley, W.G.; Hiramatsu, D.; Holz, D.E.; Howell, D.A.; Kawash, A.; Kessler, R.; Kuropatkin, N.; Lahav, O.; Lundgren, A.; Lundquist, M.; Malik, U.; Mann, A.W.; Marriner, J.; Marshall, J.L.; Martínez-Vázquez, C.E.; McCully, C.; Menanteau, F.; Meza, N.; Narayan, G.; Neilsen, E.; Nicolaou, C.; Nichol, R.; Paz-Chinchón, F.; Pereira, M.E.S.; Pineda, J.; Points, S.; Quirola-Vásquez, J.; Rembold, S.; Rest, A.; Rodriguez, Ó.; Romer, A.K.; Sako, M.; Salim, S.; Scolnic, D.; Smith, J.A.; Strader, J.; Sullivan, M.; Swanson, M.E.C.; Thomas, D.; Valenti, S.; Varga, T.N.; Walker, A.R.; Weller, J.; Wood, M.L.; Yanny, B.; Zenteno, A.; Aguena, M.; Andrade-Oliveira, F.; Bertin, E.; Brooks, D.; Burke, D.L.; Rosell, A. Carnero; Kind, M. Carrasco; Carretero, J.; Costanzi, M.; Da Costa, L.N.; De Vicente, J.; Desai, S.; Everett, S.; Ferrero, I.; Flaugher, B.; Gaztanaga, E.; Gerdes, D.W.; Gruen, D.; Gschwend, J.; Gutierrez, G.; Hinton, S.R.; Hollowood, D.L.; Honscheid, K.; James, D.J.; Kuehn, K.; Lima, M.; Maia, M.A.G.; Miquel, R.; Ogando, R.L.C.; Pieres, A.; Plazas Malagón, A.A.; Rodriguez-Monroy, M.; Sanchez, E.; Scarpine, V.; Schubnell, M.; Serrano, S.; Sevilla-Noarbe, I.; Suchyta, E.; Tarle, G.; To, C.; Zhang, Y.
    On 2019 August 14 at 21:10:39 UTC, the LIGO/Virgo Collaboration (LVC) detected a possible neutron star-black hole merger (NSBH), the first ever identified. An extensive search for an optical counterpart of this event, designated GW190814, was undertaken using the Dark Energy Camera on the 4 m Victor M. Blanco Telescope at the Cerro Tololo Inter-American Observatory. Target of Opportunity interrupts were issued on eight separate nights to observe 11 candidates using the 4.1 m Southern Astrophysical Research (SOAR) telescope's Goodman High Throughput Spectrograph in order to assess whether any of these transients was likely to be an optical counterpart of the possible NSBH merger. Here, we describe the process of observing with SOAR, the analysis of our spectra, our spectroscopic typing methodology, and our resultant conclusion that none of the candidates corresponded to the gravitational wave merger event but were all instead other transients. Finally, we describe the lessons learned from this effort. Application of these lessons will be critical for a successful community spectroscopic follow-up program for LVC observing run 4 (O4) and beyond. © 2022. The Author(s). Published by the American Astronomical Society.
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    The STRong lensing Insights into the Dark Energy Survey (STRIDES) 2016 follow-up campaign - I. Overview and classification of candidates selected by two techniques
    (Oxford University Press, 2018-11) Treu, T.; Agnello, A.; Baumer, M.A.; Birrer, S.; Buckley-Geer, E.J.; Courbin, F.; Kim, Y.J.; Lin, H.; Marshall, P.J.; Nord, B.; Schechter, P.L.; Sivakumar, P.R.; Abramson, L.E.; Anguita, T.; Apostolovski, Y.; Auger, M.W.; Chan, J.; Chen, G.; Collett, T.E.; Fassnacht, C.D.; Hsueh, J.-W.; Lemon, C.; McMahon, R.G.; Motta, V.; Ostrovski, F.; Rojas, K.; Rusu, C.E.; Williams, P.; Frieman, J.; Meylan, G.; Suyu, S.H.; Abbott, T.M.C.; Abdalla, F.B.; Allam, S.; Annis, J.; Avila, S.; Banerji, M.; Brooks, D.; Rosell, A.C.; Carrasco Kind, M.; Carretero, J.; Castander, F.J.; D'Andrea, C.B.; da Costa, L.N.; De Vicente, J.; Doel, P.; Eifler, T.F.; Flaugher, B.; Fosalba, P.; García-Bellido, J.; Goldstein, D.A.; Gruen, D.; Gruendl, R.A.; Gutierrez, G.; Hartley, W.G.; Hollowood, D.; Honscheid, K.; James, D.J.; Kuehn, K.; Kuropatkin, N.; Lima, M.; Maia, M.A.G.; Martini, P.; Menanteau, F.; Miquel, R.; Plazas, A.A.; Romer, A.K.; Sanchez, E.; Scarpine, V.; Schindler, R.; Schubnell, M.; Sevilla-Noarbe, I.; Smith, M.; Smith, R.C.; Soares-Santos, M.; Sobreira, F.; Suchyta, E.; Swanson, M.E.C.; Tarle, G.; Thomas, D.; Tucker, D.L.; Walker, A.R.
    The primary goals of the STRong lensing Insights into the Dark Energy Survey (STRIDES) collaboration are to measure the dark energy equation of state parameter and the free streaming length of dark matter. To this aim, STRIDES is discovering strongly lensed quasars in the imaging data of the Dark Energy Survey and following them up to measure time delays, high resolution imaging, and spectroscopy sufficient to construct accurate lens models. In this paper, we first present forecasts for STRIDES. Then, we describe the STRIDES classification scheme, and give an overview of the Fall 2016 follow-up campaign. We continue by detailing the results of two selection methods, the outlier selection technique and a morphological algorithm, and presenting lens models of a system that could possibly be a lensed quasar in an unusual configuration. We conclude with the summary statistics of the Fall 2016 campaign. Including searches presented in companion papers (Anguita et al.; Ostrovski et al.), STRIDES followed up 117 targets identifying 7 new strongly lensed systems, and 7 nearly identical quasars, which could be confirmed as lenses by the detection of the lens galaxy. 76 candidates were rejected and 27 remain otherwise inconclusive, for a success rate in the range of 6-35 per cent. This rate is comparable to that of previous searches like SDSS Quasar Lens Search even though the parent data set of STRIDES is purely photometric and our selection of candidates cannot rely on spectroscopic information. © 2018 The Author(s).
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    The STRong lensing Insights into the dark energy survey (STRIDES) 2017/2018 follow-up campaign: Discovery of 10 lensed quasars and 10 quasar pairs
    (Oxford University Press, 2020) Lemon, C.; Auger, M.; Anguita, T.; McMahon, R.; Apostolovski, Y.; Chen, G.; Fassnacht, C.; Melo, A.; Motta, V.; Shajib, A.; Treu, T.; Agnello, A.; Buckley-Geer, E; Schechter, P.; Birrer, S.; Collett, T.; Courbin, F.; Rusu, C.; Abbott, T.; Allam, S.; Annis, J.; Avila, S.; Bertin, E.; Brooks, D.; Burke, D.; Carnero Rosell, A.; Carrasco Kind, M.; Carretero, J.; Costanzi, M.; Costa, L.; De Vicente, J.; Desai, S.; Eifler, T.; Flaugher, B.; Frieman, J.; Garcia-Bellido, J.; Gaztanaga, E.; Gerdes, D.; Gruen, D.; Gruendl, R.; Gschwend, J.; Gutierrez, G.; Honscheid, K.; James, D.; Kim, A.; Krause, E.; Kuehn, K.; Kuropatkin, N.; Lahav, O.; Lima, M.; Lin, H.; Maia, M.; March, M.; Marshall, J.; Menanteau, F.; Miquel, R.; Palmese, A.; Paz-Chinchon, F.; Plazas, A.; Roodman, A.; Sanchez, E.; Schubnell, M.; Serrano, S.; Smith, M.; Soares-Santos, M.; Suchyta, E.; Tarle, G.; Walker, A.
    We report the results of the STRong lensing Insights into the Dark Energy Survey (STRIDES) follow-up campaign of the late 2017/early 2018 season. We obtained spectra of 65 lensed quasar candidates with ESO Faint Object Spectrograph and Camera 2 on the NTT and Echellette Spectrograph and Imager onKeck, confirming 10 newlensed quasars and 10 quasar pairs. Eight lensed quasars are doubly imaged with source redshifts between 0.99 and 2.90, one is triply imaged (DESJ0345.2545, z = 1.68), and one is quadruply imaged (quad: DESJ0053.2012, z = 3.8). Singular isothermal ellipsoid models for the doubles, based on high-resolution imaging from SAMI on Southern Astrophysical Research Telescope or Near InfraRed Camera 2 on Keck, give total magnifications between 3.2 and 5.6, and Einstein radii between 0.49 and 1.97 arcsec. After spectroscopic follow-up, we extract multi-epoch grizY photometry of confirmed lensed quasars and contaminant quasar+star pairs from DES data using parametric multiband modelling, and compare variability in each system's components. By measuring the reduced χ2 associated with fitting all epochs to the samemagnitude, we find a simple cut on the less variable component that retains all confirmed lensed quasars, while removing 94 per cent of contaminant systems. Based on our spectroscopic follow-up, this variability information improves selection of lensed quasars and quasar pairs from 34-45 per cent to 51-70 per cent, with most remaining contaminants being star-forming galaxies. Using mock lensed quasar light curves we demonstrate that selection based only on variability will over-represent the quad fraction by 10 per cent over a complete DES magnitude-limited sample, explained by the magnification bias and hence lower luminosity/more variable sources in quads.