Quasar Lensing

Courbin, F.; Saha, Prasenjit; Schechter, Paul L.

doi:10.1007/3-540-45857-3_1

Cited by 30 publications

(27 citation statements)

References 121 publications

(195 reference statements)

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Courbin, Saha & Schechter 2002). When a quasar is strongly lensed by a galaxy, it results in multiple images of the same source, accompanied by arcs or rings that map the lensed host of the quasar.…”

Section: Introductionmentioning

confidence: 99%

Discovery of two gravitationally lensed quasars in the Dark Energy Survey

Agnello¹,

Treu²,

Ostrovski

et al. 2015

Mon. Not. R. Astron. Soc.

View full text Add to dashboard Cite

We present spectroscopic confirmation of two new lensed quasars via data obtained at the 6.5m Magellan/Baade Telescope. The lens candidates have been selected from the Dark Energy Survey (DES) and WISE based on their multi-band photometry and extended morphology in DES images. Images of DES J0115−5244 show two blue point sources at either side of a red galaxy. Our long-slit data confirm that both point sources are images of the same quasar at z s = 1.64. The Einstein Radius estimated from the DES images is 0.51 . DES J2146−0047 is in the area of overlap between DES and the Sloan Digital Sky Survey (SDSS). Two blue components are visible in the DES and SDSS images. The SDSS fiber spectrum shows a quasar component at z s = 2.38 and absorption compatible with Mg II and Fe II at z l = 0.799, which we tentatively associate with the foreground lens galaxy. The long-slit Magellan spectra show that the blue components are resolved images of the same quasar. The Einstein Radius is 0.68 corresponding to an enclosed mass of 1.6 × 10 11 M . Three other candidates were observed and rejected, two being low-redshift pairs of starburst galaxies, and one being a quasar behind a blue star. These first confirmation results provide an important empirical validation of the data-mining and model-based selection that is being applied to the entire DES dataset.

show abstract

Section: Introductionmentioning

confidence: 99%

Discovery of two gravitationally lensed quasars in the Dark Energy Survey

Agnello¹,

Treu²,

Ostrovski

et al. 2015

Mon. Not. R. Astron. Soc.

View full text Add to dashboard Cite

show abstract

“…2005), the so-called time delay between the images of most gravitationally lensed quasars. These time delays are used in combination with lens models and detailed observations of individual systems to infer the value of the Hubble parameter H 0 , independent of any standard candle (e.g., reviews by Courbin et al 2002;Kochanek 2005a).…”

Section: Introductionmentioning

confidence: 99%

COSMOGRAIL: the COSmological MOnitoring of GRAvItational Lenses

Eigenbrod¹,

Courbin²,

Dye

et al. 2006

A&A

View full text Add to dashboard Cite

Aims. To provide the observational constraints required to use the gravitationally lensed quasar SDSS J0924+0219 for the determination of H 0 from the time delay method. We measure here the redshift of the lensing galaxy, we show the spectral variability of the source, and we resolve the lensed host galaxy of the source. Methods. We present our VLT/FORS1 deep spectroscopic observations of the lensed quasar SDSS J0924+0219, as well as archival HST/NICMOS and ACS images of the same object. The two-epoch spectra, obtained in the Multi Object Spectroscopy (MOS) mode, allow for very accurate flux calibration and spatial deconvolution. This strategy provides spectra for the lensing galaxy and for the quasar images A and B, free of any mutual light contamination. We deconvolve the HST images as well, which reveal a double Einstein ring. The mass distributions in the lens, reconstructed in several ways, are compared. Results. We determine the redshift of the lensing galaxy in SDSS J0924+0219: z lens = 0.394 ± 0.001. Only slight spectral variability is seen in the continuum of quasar images A and B, while the C III], Mg II and Fe II emission lines display obvious changes. The flux ratio between the quasar images A and B is the same in the emission lines and in the continuum. One of the Einstein rings found using deconvolution corresponds to the lensed quasar host galaxy at z = 1.524 and a second bluer one, is the image either of a star-forming region in the host galaxy, or of another unrelated lower redshift object. A broad range of lens models give a satisfactory fit to the data. However, they predict very different time delays, making SDSS J0924+0219 an object of particular interest for photometric monitoring. In addition, the lens models reconstructed using exclusively the constraints from the Einstein rings, or using exclusively the astrometry of the quasar images, are not compatible. This suggests that multipole-like structures play an important role in SDSS J0924+0219.

show abstract

“…It not only provides a more convenient way to get the lens equation (Schneider 1985;Blandford & Narayan 1986) but also has some important values in its own right (for more complete reviews, see Courbin et al 2002;Kochanek & Schechter 2004). As it is an alterative to the cold dark matter, it should be very interesting to study the behavior of time delay in TeVeS.…”

Section: Time Delaymentioning

confidence: 99%

Theoretical Aspects of Gravitational Lensing in TeVeS

Chiu

Tian

2006

ApJ

View full text Add to dashboard Cite

Since Bekenstein's creation of his tensor-vector-scalar theory (TeVeS), the modified Newtonian dynamics (MOND) paradigm has been redeemed from the embarrassment of lacking a relativistic version. One primary success of TeVeS is that it provides an enhancement of gravitational lensing, which could not be achieved by other MOND theories. Following Bekenstein's work, we investigate the phenomena of gravitational lensing including deflection angles, lens equations, and time delay. We find that the deflection angle maintains its value, while the distance of closest approach varies in the MOND regime. We also use the deflection angle law to derive magnifications and investigate microlensing light curves. We find that the difference in the magnification of the two images in the point-mass model is not a constant, as in general relativity (GR). Besides, microlensing light curves could deviate significantly from GR in the deep MOND regime. Furthermore, the scalar field, which is introduced to enhance the deflection angle in TeVeS, contributes a negative effect on the potential time delay. Unfortunately, this phenomenon is unmeasurable in lensing systems, where we can only observe the time delay between two images for a given source. However, this measurable time delay offers another constraint on the mass ratio of the dark matter and MOND scenarios, which in general differs from that given by the deflection angle. In other words, for a lensing system, if two masses, m gN and m gM , are mutual alternatives for the deflection angles in their own paradigm, regarding the time delay they are in general in an exclusive relation.

show abstract

Quasar Lensing

Cited by 30 publications

References 121 publications

Discovery of two gravitationally lensed quasars in the Dark Energy Survey

Discovery of two gravitationally lensed quasars in the Dark Energy Survey

COSMOGRAIL: the COSmological MOnitoring of GRAvItational Lenses

Theoretical Aspects of Gravitational Lensing in TeVeS

Contact Info

Product

Resources

About