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Title: COSMOGRAIL: the COSmological MOnitoring of GRAvItational Lenses: XVI. Time delays for the quadruply imaged quasar DES J0408–5354 with high-cadence photometric monitoring* [COSMOGRAIL XVI: Time delays for the quadruply imaged quasar DES J0408–5354 with high-cadence photometric monitoring]

Abstract

Here, we present time-delay measurements for the new quadruple imaged quasar DES J0408–5354, the first quadruple imaged quasar found in the Dark Energy Survey (DES). Our result is made possible by implementing a new observational strategy using almost daily observations with the MPIA 2.2 m telescope at La Silla observatory and deep exposures reaching a signal-to-noise ratio of about 1000 per quasar image. This data qualityallows us to catch small photometric variations (a few mmag rms) of the quasar, acting on temporal scales much shorter than microlensing, and hence making the time delay measurement very robust against microlensing. In only seven months we very accurately measured one of the time delays in DES J0408–5354: Δt(AB) = –112.1 ± 2.1 days (1.8%) using only the MPIA 2.2 m data. In combination with data taken with the 1.2 m Euler Swiss telescope, we also measured two delays involving the D component of the system Δt(AD) = –155.5 ± 12.8 days (8.2%) and Δt(BD) = –42.4 ± 17.6 days (41%), where all the error bars include systematics. Turning these time delays into cosmological constraints will require deep Hubble Space Telescope (HST) imaging or ground-based adaptive optics (AO), and information on the velocity fieldmore » of the lensing galaxy.« less

Authors:
; ORCiD logo; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; more »; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; « less
Publication Date:
Research Org.:
SLAC National Accelerator Lab., Menlo Park, CA (United States)
Sponsoring Org.:
USDOE
OSTI Identifier:
1419986
Grant/Contract Number:
AC02-76SF00515
Resource Type:
Journal Article: Accepted Manuscript
Journal Name:
Astronomy and Astrophysics
Additional Journal Information:
Journal Volume: 609; Journal ID: ISSN 0004-6361
Publisher:
EDP Sciences
Country of Publication:
United States
Language:
English
Subject:
79 ASTRONOMY AND ASTROPHYSICS; methods: data analysis; gravitational lensing: strong; cosmological parameters

Citation Formats

Courbin, F., Bonvin, V., Buckley-Geer, E., Fassnacht, C. D., Frieman, J., Lin, H., Marshall, P. J., Suyu, S. H., Treu, T., Anguita, T., Motta, V., Meylan, G., Paic, E., Tewes, M., Agnello, A., Chao, D. C. -Y., Chijani, M., Gilman, D., Rojas, K., Williams, P., Hempel, A., Kim, S., Lachaume, R., Rabus, M., Abbott, T. M. C., Allam, S., Annis, J., Banerji, M., Bechtol, K., Benoit-Lévy, A., Brooks, D., Burke, D. L., Carnero Rosell, A., Carrasco Kind, M., Carretero, J., D’Andrea, C. B., da Costa, L. N., Davis, C., DePoy, D. L., Desai, S., Flaugher, B., Fosalba, P., García-Bellido, J., Gaztanaga, E., Goldstein, D. A., Gruen, D., Gruendl, R. A., Gschwend, J., Gutierrez, G., Honscheid, K., James, D. J., Kuehn, K., Kuhlmann, S., Kuropatkin, N., Lahav, O., Lima, M., Maia, M. A. G., March, M., Marshall, J. L., McMahon, R. G., Menanteau, F., Miquel, R., Nord, B., Plazas, A. A., Sanchez, E., Scarpine, V., Schindler, R., Schubnell, M., Sevilla-Noarbe, I., Smith, M., Soares-Santos, M., Sobreira, F., Suchyta, E., Tarle, G., Tucker, D. L., Walker, A. R., and Wester, W. COSMOGRAIL: the COSmological MOnitoring of GRAvItational Lenses: XVI. Time delays for the quadruply imaged quasar DES J0408–5354 with high-cadence photometric monitoring* [COSMOGRAIL XVI: Time delays for the quadruply imaged quasar DES J0408–5354 with high-cadence photometric monitoring]. United States: N. p., 2018. Web. doi:10.1051/0004-6361/201731461.
Courbin, F., Bonvin, V., Buckley-Geer, E., Fassnacht, C. D., Frieman, J., Lin, H., Marshall, P. J., Suyu, S. H., Treu, T., Anguita, T., Motta, V., Meylan, G., Paic, E., Tewes, M., Agnello, A., Chao, D. C. -Y., Chijani, M., Gilman, D., Rojas, K., Williams, P., Hempel, A., Kim, S., Lachaume, R., Rabus, M., Abbott, T. M. C., Allam, S., Annis, J., Banerji, M., Bechtol, K., Benoit-Lévy, A., Brooks, D., Burke, D. L., Carnero Rosell, A., Carrasco Kind, M., Carretero, J., D’Andrea, C. B., da Costa, L. N., Davis, C., DePoy, D. L., Desai, S., Flaugher, B., Fosalba, P., García-Bellido, J., Gaztanaga, E., Goldstein, D. A., Gruen, D., Gruendl, R. A., Gschwend, J., Gutierrez, G., Honscheid, K., James, D. J., Kuehn, K., Kuhlmann, S., Kuropatkin, N., Lahav, O., Lima, M., Maia, M. A. G., March, M., Marshall, J. L., McMahon, R. G., Menanteau, F., Miquel, R., Nord, B., Plazas, A. A., Sanchez, E., Scarpine, V., Schindler, R., Schubnell, M., Sevilla-Noarbe, I., Smith, M., Soares-Santos, M., Sobreira, F., Suchyta, E., Tarle, G., Tucker, D. L., Walker, A. R., & Wester, W. COSMOGRAIL: the COSmological MOnitoring of GRAvItational Lenses: XVI. Time delays for the quadruply imaged quasar DES J0408–5354 with high-cadence photometric monitoring* [COSMOGRAIL XVI: Time delays for the quadruply imaged quasar DES J0408–5354 with high-cadence photometric monitoring]. United States. doi:10.1051/0004-6361/201731461.
Courbin, F., Bonvin, V., Buckley-Geer, E., Fassnacht, C. D., Frieman, J., Lin, H., Marshall, P. J., Suyu, S. H., Treu, T., Anguita, T., Motta, V., Meylan, G., Paic, E., Tewes, M., Agnello, A., Chao, D. C. -Y., Chijani, M., Gilman, D., Rojas, K., Williams, P., Hempel, A., Kim, S., Lachaume, R., Rabus, M., Abbott, T. M. C., Allam, S., Annis, J., Banerji, M., Bechtol, K., Benoit-Lévy, A., Brooks, D., Burke, D. L., Carnero Rosell, A., Carrasco Kind, M., Carretero, J., D’Andrea, C. B., da Costa, L. N., Davis, C., DePoy, D. L., Desai, S., Flaugher, B., Fosalba, P., García-Bellido, J., Gaztanaga, E., Goldstein, D. A., Gruen, D., Gruendl, R. A., Gschwend, J., Gutierrez, G., Honscheid, K., James, D. J., Kuehn, K., Kuhlmann, S., Kuropatkin, N., Lahav, O., Lima, M., Maia, M. A. G., March, M., Marshall, J. L., McMahon, R. G., Menanteau, F., Miquel, R., Nord, B., Plazas, A. A., Sanchez, E., Scarpine, V., Schindler, R., Schubnell, M., Sevilla-Noarbe, I., Smith, M., Soares-Santos, M., Sobreira, F., Suchyta, E., Tarle, G., Tucker, D. L., Walker, A. R., and Wester, W. 2018. "COSMOGRAIL: the COSmological MOnitoring of GRAvItational Lenses: XVI. Time delays for the quadruply imaged quasar DES J0408–5354 with high-cadence photometric monitoring* [COSMOGRAIL XVI: Time delays for the quadruply imaged quasar DES J0408–5354 with high-cadence photometric monitoring]". United States. doi:10.1051/0004-6361/201731461.
@article{osti_1419986,
title = {COSMOGRAIL: the COSmological MOnitoring of GRAvItational Lenses: XVI. Time delays for the quadruply imaged quasar DES J0408–5354 with high-cadence photometric monitoring* [COSMOGRAIL XVI: Time delays for the quadruply imaged quasar DES J0408–5354 with high-cadence photometric monitoring]},
author = {Courbin, F. and Bonvin, V. and Buckley-Geer, E. and Fassnacht, C. D. and Frieman, J. and Lin, H. and Marshall, P. J. and Suyu, S. H. and Treu, T. and Anguita, T. and Motta, V. and Meylan, G. and Paic, E. and Tewes, M. and Agnello, A. and Chao, D. C. -Y. and Chijani, M. and Gilman, D. and Rojas, K. and Williams, P. and Hempel, A. and Kim, S. and Lachaume, R. and Rabus, M. and Abbott, T. M. C. and Allam, S. and Annis, J. and Banerji, M. and Bechtol, K. and Benoit-Lévy, A. and Brooks, D. and Burke, D. L. and Carnero Rosell, A. and Carrasco Kind, M. and Carretero, J. and D’Andrea, C. B. and da Costa, L. N. and Davis, C. and DePoy, D. L. and Desai, S. and Flaugher, B. and Fosalba, P. and García-Bellido, J. and Gaztanaga, E. and Goldstein, D. A. and Gruen, D. and Gruendl, R. A. and Gschwend, J. and Gutierrez, G. and Honscheid, K. and James, D. J. and Kuehn, K. and Kuhlmann, S. and Kuropatkin, N. and Lahav, O. and Lima, M. and Maia, M. A. G. and March, M. and Marshall, J. L. and McMahon, R. G. and Menanteau, F. and Miquel, R. and Nord, B. and Plazas, A. A. and Sanchez, E. and Scarpine, V. and Schindler, R. and Schubnell, M. and Sevilla-Noarbe, I. and Smith, M. and Soares-Santos, M. and Sobreira, F. and Suchyta, E. and Tarle, G. and Tucker, D. L. and Walker, A. R. and Wester, W.},
abstractNote = {Here, we present time-delay measurements for the new quadruple imaged quasar DES J0408–5354, the first quadruple imaged quasar found in the Dark Energy Survey (DES). Our result is made possible by implementing a new observational strategy using almost daily observations with the MPIA 2.2 m telescope at La Silla observatory and deep exposures reaching a signal-to-noise ratio of about 1000 per quasar image. This data qualityallows us to catch small photometric variations (a few mmag rms) of the quasar, acting on temporal scales much shorter than microlensing, and hence making the time delay measurement very robust against microlensing. In only seven months we very accurately measured one of the time delays in DES J0408–5354: Δt(AB) = –112.1 ± 2.1 days (1.8%) using only the MPIA 2.2 m data. In combination with data taken with the 1.2 m Euler Swiss telescope, we also measured two delays involving the D component of the system Δt(AD) = –155.5 ± 12.8 days (8.2%) and Δt(BD) = –42.4 ± 17.6 days (41%), where all the error bars include systematics. Turning these time delays into cosmological constraints will require deep Hubble Space Telescope (HST) imaging or ground-based adaptive optics (AO), and information on the velocity field of the lensing galaxy.},
doi = {10.1051/0004-6361/201731461},
journal = {Astronomy and Astrophysics},
number = ,
volume = 609,
place = {United States},
year = 2018,
month = 1
}

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  • We report the discovery and spectroscopic confirmation of the quad-like lensed quasar system DES J0408-5354 found in the Dark Energy Survey (DES) Year 1 (Y1) data. This system was discovered during a search for DES Y1 strong lensing systems using a method that identified candidates as red galaxies with multiple blue neighbors. DES J0408-5354 consists of a central red galaxy surrounded by three bright (more » $$i\lt 20$$) blue objects and a fourth red object. Subsequent spectroscopic observations using the Gemini South telescope confirmed that the three blue objects are indeed the lensed images of a quasar with redshift z = 2.375, and that the central red object is an early-type lensing galaxy with redshift z = 0.597. DES J0408-5354 is the first quad lensed quasar system to be found in DES and begins to demonstrate the potential of DES to discover and dramatically increase the sample size of these very rare objects.« less
  • We present gravitational lens models of the multiply imaged quasar DES J0408-5354, recently discovered in the Dark Energy Survey (DES) footprint, with the aim of interpreting its remarkable quad-like configuration. We first model the DES single-epochmore » $grizY$ images as a superposition of a lens galaxy and four point-like objects, obtaining spectral energy distributions (SEDs) and relative positions for the objects. Three of the point sources (A,B,D) have SEDs compatible with the discovery quasar spectra, while the faintest point-like image (G2/C) shows significant reddening and a `grey' dimming of $$\approx0.8$$mag. In order to understand the lens configuration, we fit different models to the relative positions of A,B,D. Models with just a single deflector predict a fourth image at the location of G2/C but considerably brighter and bluer. The addition of a small satellite galaxy ($$R_{\rm E}\approx0.2$$") in the lens plane near the position of G2/C suppresses the flux of the fourth image and can explain both the reddening and grey dimming. All models predict a main deflector with Einstein radius between $1.7"$ and $2.0",$ velocity dispersion $267-280$km/s and enclosed mass $$\approx 6\times10^{11}M_{\odot},$$ even though higher resolution imaging data are needed to break residual degeneracies in model parameters. The longest time-delay (B-A) is estimated as $$\approx 85$$ (resp. $$\approx125$$) days by models with (resp. without) a perturber near G2/C. The configuration and predicted time-delays of J0408-5354 make it an excellent target for follow-up aimed at understanding the source quasar host galaxy and substructure in the lens, and measuring cosmological parameters. We also discuss some lessons learnt from J0408-5354 on lensed quasar finding strategies, due to its chromaticity and morphology.« less
  • We report the discovery and spectroscopic confirmation of the quad-like lensed quasar system DES J0408-5354 found in the Dark Energy Survey (DES) Year 1 (Y1) data. This system was discovered during a search for DES Y1 strong lensing systems using a method that identified candidates as red galaxies with multiple blue neighbors. DES J0408-5354 consists of a central red galaxy surrounded by three bright (more » $$i\lt 20$$) blue objects and a fourth red object. Subsequent spectroscopic observations using the Gemini South telescope confirmed that the three blue objects are indeed the lensed images of a quasar with redshift z = 2.375, and that the central red object is an early-type lensing galaxy with redshift z = 0.597. DES J0408-5354 is the first quad lensed quasar system to be found in DES and begins to demonstrate the potential of DES to discover and dramatically increase the sample size of these very rare objects.« less
  • We report the discovery and spectroscopic con rmation of the quad-like lensed quasar system DES J0408-5354 found in the Dark Energy Survey (DES) Year 1 (Y1) data. This system was discovered during a search for DES Y1 strong lensing systems using a method that identi ed candidates as red galaxies with multiple blue neighbors. DES J0408-5354 consists of a central red galaxy surrounded by three bright (i < 20) blue objects and a fourth red object. Subsequent spectroscopic observations using the Gemini South telescope con rmed that the three blue objects are indeed the lensed images of a quasar withmore » redshift z = 2:375, and that the central red object is an early-type lensing galaxy with redshift z = 0:597. DES J0408-5354 is the rst quad lensed quasar system to be found in DES and begins to demonstrate the potential of DES to discover and dramatically increase the sample size of these very rare objects.« less
  • We present detailed modelling of the recently discovered, quadruply lensed quasar J0408-5354, with the aim of interpreting its remarkable configuration: besides three quasar images (A,B,D) around the main deflector (G1), a fourth image (C) is significantly reddened and dimmed by a perturber (G2) which is not detected in the Dark Energy Survey imaging data. From lens models incorporating (dust-corrected) flux ratios, we find a perturber Einstein radius 0.04 arcsec ≲ RE, G2 ≲ 0.2 arcsec and enclosed mass M p(R E, G2) ≲ 1.0 × 10 10 M⊙. The main deflector has stellar mass log10 (M */M⊙) =11.49more » $$+0.46\atop{-0.32}$$ log10 (M */M⊙)=11.49-0.32+0.46 , a projected mass M p(R E, G1) ≈ 6 × 10 11 M⊙ within its Einstein radius R E, G1 = (1.85 ± 0.15) arcsec and predicted velocity dispersion 267–280 km s -1. Follow-up images from a companion monitoring campaign show additional components, including a candidate second source at a redshift between the quasar and G1. Models with free perturbers, and dust-corrected and delay-corrected flux ratios, are also explored. The predicted time-delays (Δt AB = (135.0 ± 12.6) d, Δt BD = (21.0 ± 3.5) d) roughly agree with those measured, but better imaging is required for proper modelling and comparison. Lastly, we also discuss some lessons learnt from J0408-5354 on lensed quasar finding strategies, due to its chromaticity and morphology.« less
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