J/A+A/672/L9 Lensed quasar eRASS1 J050129.5-073309 (Tubin-Arenas+, 2023)
Discovery of the lensed quasar eRASS1 J050129.5-073309 with
SRG/eROSITA and Gaia.
Tubin-Arenas D., Lamer G., Krumpe M., Urrutia T., Schwope A., Brogan R.,
Comparat J., Salvato M., Bulbul E., Garrel C., Schramm M., Liu T.
<Astron. Astrophys. 672, L9 (2023)>
=2023A&A...672L...9T 2023A&A...672L...9T (SIMBAD/NED BibCode)
ADC_Keywords: Gravitational lensing ; Spectra, optical ;
Photometry ; Optical
Keywords: gravitational lensing: strong -
quasars: individual: eRASS1 J050129.5-073309 - X-rays: general
Abstract:
We report the discovery and spectroscopic identification of the bright
doubly lensed quasar eRASS1 J050129.5-073309 at redshift z=2.47,
selected from the first all-sky survey of the Spectrum Roentgen Gamma
(SRG) eROSITA telescope and the Gaia EDR3 catalog. We systematically
searched for extragalactic sources with eROSITA X-ray positions that
have multiple Gaia counterparts, and we have started spectroscopic
follow-up of the most promising candidates using long-slit
spectroscopy with NTT/EFOSC2 to confirm the lens nature. The two
images are separated by 2.7", and their average Gaia g-band
magnitudes are 16.95 and 17.33. Legacy Survey DR10 imaging and image
modeling reveal both the lensing galaxy and tentatively the lensed
image of the quasar host galaxy. Archival optical light curves show
evidence of a variability time delay, with the fainter component
lagging the brighter by about 100 days. The brightness of the fainter
image has also decreased by about one magnitude since 2019. This
dimming was still obvious at the time of the spectroscopic
observations and is probably caused by microlensing. The optical
spectroscopic follow-up obtained from NTT/EFOSC2 and the evidence
provided by the imaging and timing analysis allow us to confirm the
lensed nature of eRASS1 J050129.5-073309.
Description:
ESO NTT/EFOSC2 spectra and Gaia+ZTF ligh curve data of the recently
discovered lensed quasar eRASS1 J050129.5-073309.
Objects:
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RA (2000) DE Designation(s)
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05 01 29.42 -07 33 07.1 eRASS1 J050129.5-073309 image A
05 01 29.56 -07 33 05.5 eRASS1 J050129.5-073309 image B
05 01 29.45 -07 33 05.8 eRASS1 J050129.5-073309 lensing galaxy
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File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
lc.dat 124 168 Light curve
spectra.dat 99 1003 Spectra
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Byte-by-byte Description of file: lc.dat
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Bytes Format Units Label Explanations
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1- 24 E24.19 d MJD Heliocenrtic modified Julian date
26- 49 E24.19 mag magA Magnitude of image A
51- 74 E24.19 mag e_magA Magnitude of image A error
76- 99 E24.19 mag magB Magnitude of image B
101-124 E24.19 mag e_magB Magnitude of image B error
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Byte-by-byte Description of file: spectra.dat
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Bytes Format Units Label Explanations
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3- 24 E22.18 0.1nm lambda Wavelength
28- 49 E22.18 mW/m2 FluxA Flux of image A (erg/s/cm2)
53- 74 E22.18 mW/m2 FluxB Flux of image B (erg/s/cm2)
77- 99 E23.18 mW/m2 Fluxg Flux of lensing galaxy (erg/s/cm2)
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Acknowledgements:
Dusan Tubin-Arenas, dtubin(at)aip.de
(End) Patricia Vannier [CDS] 12-Apr-2023