J/A+A/694/A31 r-band light curves of FBQ 0951+2635 (Shalyapin+, 2025)
FBQ 0951+2635: Time delay and structure of the main lensing galaxy.
Shalyapin V.N., Goicoechea L.J., Ruiz-Hinojosa E.
<Astron. Astrophys. 694, A31 (2025)>
=2025A&A...694A..31S 2025A&A...694A..31S (SIMBAD/NED BibCode)
ADC_Keywords: Gravitational lensing ; QSOs ; Photometry, CCD ; Optical
Keywords: gravitational lensing: strong - galaxies: structure -
quasars: individual: FBQ 0951+2635
Abstract:
As there is a long-standing controversy over the time delay between
the two images of the gravitationally lensed quasar FBQ 0951+2635, we
combined early and new optical light curves to robustly measure a
delay of 13.5±1.6d (1σ interval). The new optical records
covering the last 17 yr were also used to trace the long-timescale
evolution of the microlensing variability. Additionally, the new time
delay interval and a relatively rich set of further observational
constraints allowed us to discuss the mass structure of the main
lensing galaxy at redshift 0.26. This lens system is of particular
interest because the external shear from secondary gravitational
deflectors is relatively low, but the external convergence is one of
the highest known. When modelling the galaxy as a singular power-law
ellipsoid without hypotheses/priors on the power-law index,
ellipticity and position angle, we demonstrated that its mass profile
is close to isothermal, and there is good alignment between mass and
near-IR light. We also recovered the true mass scale of the galaxy.
Finally, it is worth mentioning that a constant mass-to-light ratio
model also worked acceptably well.
Description:
Table 1 contains updated r-band brightness records of the two images
(A and B) of the gravitationally lensed quasar FBQ 0951+2635 covering
the period from 2008 to 2024. Although most photometric data are based
on observations with the 2.0m Liverpool Telescope (LT; see 2009-2016
records in Gil-Merino et al., 2018A&A...616A.118G 2018A&A...616A.118G, Cat.
J/A+A/618/A118) and the 1.55m Kaj Strand Telescope (KST; Rivera et
al., 2023ApJ...952...54R 2023ApJ...952...54R), the light curves also include several
magnitudes in the Data Release 1 of Pan-STARRS (PS; Flewelling et al.
2020ApJS..251....7F 2020ApJS..251....7F) and the Data Release 2 of the Dark Energy Survey
(DES; Abbott et al.. 2021ApJS..255...20A 2021ApJS..255...20A, Cat. II/371).
Objects:
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RA (2000) DE Designation(s)
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09 51 22.58 +26 35 13.7 FBQ 0951+2635 = FBQS J0951+2635
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File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table1.dat 39 213 Light curves in the r band (623.7nm)
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Byte-by-byte Description of file: table1.dat
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Bytes Format Units Label Explanations
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1- 9 F9.3 d MJD Modified Julian Date
11- 16 F6.3 mag rmagA r magnitude of FBQ 0951+2635A
18- 22 F5.3 mag e_rmagA Error in r magnitude of FBQ 0951+2635A
24- 29 F6.3 mag rmagB r magnitude of FBQ 0951+2635B
31- 35 F5.3 mag e_rmagB Error in r magnitude of FBQ 0951+2635B
37- 39 A3 --- Tel/DB Telescope/Database used (LT, KST, PS or DES)
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Acknowledgements:
Luis Goicoechea, goicol(at)unican.es
(End) L. Goicoechea [IFCA (CSIC-UC), Spain], P. Vannier [CDS] 16-Dec-2024