J/A+A/683/A119 VR light curves of three lensed quasars (Sorgenfrei+, 2024)
Improving the light curves of gravitationally lensed quasars
with Gaia proper motion data.
Sorgenfrei C., Schmidt R.W., Wambsganss J.
<Astron. Astrophys. 683, A119 (2024)>
=2024A&A...683A.119S 2024A&A...683A.119S (SIMBAD/NED BibCode)
ADC_Keywords: Gravitational lensing ; Photometry ; Optical
Keywords: gravitational lensing: strong - gravitational lensing: micro -
techniques: photometric - astrometry - proper motions -
quasars: general
Abstract:
We show how to significantly improve difference image analysis
(DIA) of gravitationally lensed quasars over long periods of time
using Gaia proper motions.
DIA requires the subtraction of a reference image from the individual
images of a monitoring campaign, using stars in the field to align the
images. Since the proper motion of the stars can be of the same order
as the pixel size during a several-year campaign, we use Gaia DR3
proper motions to enable a correct image alignment. The proper motion
corrected star positions can be aligned by the ISIS package. DIA is
carried out using the HOTPAnTS package. We apply point spread function
(PSF) photometry to obtain light curves and add a proper motion
correction of the PSF star to GALFIT.
We apply our method to the light curves of the three gravitationally
lensed quasars HE1104-1805, HE2149-2745 and Q2237+0305 in the R and V
band, respectively, obtained using 1 m telescopes of the Las Cumbres
Observatory from 2014 to 2022. We show that the image alignment and
the determination of the lensed quasar positions is significantly
improved by this method. The light curves of individual quasar images
display intrinsic quasar variations and are affected by chromatic
microlensing.
Description:
The six files (he1104r.dat, he1104v.dat, he2149r.dat, he2149v.dat,
q2237r.dat and q2237v.dat) contain light curves of the multiple images
of the gravitationally lensed quasars HE1104-1805, HE2149-2745 and
Q2237+0305 (a.k.a. Einstein Cross) in the R-band and the V-band from
data taken at the Las Cumbres Observatory (LCO) from 2014 to 2022.
Objects:
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RA (2000) DE Designation(s)
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11 06 33.38 -18 21 23.8 HE 1104-1805 = QSO J1106-1821
21 52 07.45 -27 31 49.7 HE 2149-2745 = QSO B2149-2745
22 40 30.23 +03 21 30.6 Q 2237+0305 = QSO J2240+0321
--------------------------------------------------------
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . Thsi file
stars.dat 59 3 List of studied stars
he1104v.dat 72 86 V-band light curves of HE1104-1805
he1104r.dat 72 76 R-band light curves of HE1104-1805
he2149v.dat 72 103 V-band light curves of HE2149-2745
he2149r.dat 72 124 R-band light curves of HE2149-2745
q2237v.dat 72 93 V-band light curves of Q2237+0305
q2237r.dat 72 94 R-band light curves of Q2237+0305
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Byte-by-byte Description of file: stars.dat
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Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 11 A11 --- Name Star name
13- 14 I2 h RAh Right ascension (J2000)
16- 17 I2 min RAm Right ascension (J2000)
19- 23 F5.2 s RAs Right ascension (J2000)
25 A1 --- DE- Declination sign (J2000)
26- 27 I2 deg DEd Declination (J2000)
29- 30 I2 arcmin DEm Declination (J2000)
32- 35 F4.1 arcsec DEs Declination (J2000)
37- 47 A11 --- FileName1 Name of the table with R data
49- 59 A11 --- FileName2 Name of the table with V data
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Byte-by-byte Description of file: he1104r.dat he2149r.dat q2237r.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
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1- 10 F10.4 d MJD Modified Julian Date
12- 18 F7.4 mag RmagA R magnitude for image A
20- 25 F6.4 mag e_RmagA Error on RmagA
27- 33 F7.4 mag RmagB R magnitude for image B
35- 40 F6.4 mag e_RmagB Error on RmagB
42- 48 F7.4 mag RmagC ? R magnitude for image C (only for Q2237+0305)
50- 55 F6.4 mag e_RmagC ? Error on RmagC (only for Q2237+0305)
57- 63 F7.4 mag RmagD ? R magnitude for image D (only for Q2237+0305)
65- 70 F6.4 mag e_RmagD ? Error on RmagD (only for Q2237+0305)
72 A1 --- Band [R] Observed band
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Byte-by-byte Description of file: he1104v.dat he2149v.dat q2237v.dat
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Bytes Format Units Label Explanations
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1- 10 F10.4 d MJD Modified Julian Date
12- 18 F7.4 mag VmagA V magnitude for image A
20- 25 F6.4 mag e_VmagA Error on VmagA
27- 33 F7.4 mag VmagB V magnitude for image B
35- 40 F6.4 mag e_VmagB Error on VmagB
42- 48 F7.4 mag VmagC ? V magnitude for image C (only for Q2237+0305)
50- 55 F6.4 mag e_VmagC ? Error on VmagC (only for Q2237+0305)
57- 63 F7.4 mag VmagD ? V magnitude for image D (only for Q2237+0305)
65- 70 F6.4 mag e_VmagD ? Error on VmagD (only for Q2237+0305)
72 A1 --- Band [V] Observed band
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Acknowledgements:
Christian Sorgenfrei, c.sorgenfrei(at)stud.uni-heidelberg.de
(End) Patricia Vannier [CDS] 11-Jan-2024