Gravitational lensing, time delay, and angular diameter distance

1991 ◽  
Vol 378 ◽  
pp. L5 ◽  
Author(s):  
Ramesh Narayan
Keyword(s):  
Time Delay ◽  
Gravitational Lensing ◽  
Angular Diameter ◽  
Angular Diameter Distance

scholarly journals HOLISMOKES

2020 ◽  
Vol 644 ◽  
pp. A162
Author(s):  
S. H. Suyu ◽  
S. Huber ◽  
R. Cañameras ◽  
M. Kromer ◽  
S. Schuldt ◽  
...  
Keyword(s):  
Time Delay ◽  
Gravitational Lensing ◽  
Early Phase ◽  
Rest Frame ◽  
Hubble Constant ◽  
Angular Diameter ◽  
Strong Gravitational Lensing ◽  
Space And Time ◽  
Precise Time

We present the HOLISMOKES programme on strong gravitational lensing of supernovae (SNe) as a probe of SN physics and cosmology. We investigate the effects of microlensing on early-phase SN Ia spectra using four different SN explosion models. We find that distortions of SN Ia spectra due to microlensing are typically negligible within ten rest-frame days after a SN explosion (< 1% distortion within the 1σ spread and ≲10% distortion within the 2σ spread). This shows the great prospects of using lensed SNe Ia to obtain intrinsic early-phase SN spectra for deciphering SN Ia progenitors. As a demonstration of the usefulness of lensed SNe Ia for cosmology, we simulate a sample of mock lensed SN Ia systems that are expected to have accurate and precise time-delay measurements in the era of the Rubin Observatory Legacy Survey of Space and Time (LSST). Adopting realistic yet conservative uncertainties on their time-delay distances and lens angular diameter distances, of 6.6% and 5%, respectively, we find that a sample of 20 lensed SNe Ia would allow us to constrain the Hubble constant (H0) with 1.3% uncertainty in the flat ΛCDM cosmology. We find a similar constraint on H0 in an open ΛCDM cosmology, while the constraint degrades to 3% in a flat wCDM cosmology. We anticipate lensed SNe to be an independent and powerful probe of SN physics and cosmology in the upcoming LSST era.

scholarly journals A geometric probe of cosmology – I. Gravitational lensing time delays and quasar reverberation mapping

2019 ◽  
Vol 492 (1) ◽  
pp. 1102-1109
Author(s):  
Angela L H Ng ◽  
Geraint F Lewis
Keyword(s):  
Gravitational Lensing ◽  
Time Delays ◽  
Angular Diameter ◽  
Distance Ratio ◽  
Angular Diameter Distance ◽  
Reverberation Mapping ◽  
Source Effects ◽  
Spectroscopic Monitoring ◽  
Line Region ◽  
Image Separation

ABSTRACT We present a novel, purely geometric probe of cosmology based on measurements of differential time delays between images of strongly lensed quasars due to finite source effects. Our approach is solely dependent on cosmology via a ratio of angular diameter distances, the image separation, and the source size. It thereby entirely avoids the challenges of lens modelling that conventionally limit time delay cosmography, and instead entails the lensed reverberation mapping of the quasar broad-line region. We demonstrate that differential time delays are measurable with short-cadence spectroscopic monitoring of lensed quasars, through the timing of kinematically identified features within the broad emission lines. This provides a geometric determination of an angular diameter distance ratio complementary to standard probes, and as a result is a potentially powerful new method of constraining cosmology.

Strong Gravitational Lensing Time Delay Statistics and the Density Profile of Dark Halos

2002 ◽  
Vol 568 (2) ◽  
pp. 488-499 ◽  
Author(s):  
Masamune Oguri ◽  
Atsushi Taruya ◽  
Yasushi Suto ◽  
Edwin L. Turner
Keyword(s):  
Time Delay ◽  
Density Profile ◽  
Gravitational Lensing ◽  
Strong Gravitational Lensing

scholarly journals THE MEGAMASER COSMOLOGY PROJECT. II. THE ANGULAR-DIAMETER DISTANCE TO UGC 3789

2010 ◽  
Vol 718 (2) ◽  
pp. 657-665 ◽  
Author(s):  
J. A. Braatz ◽  
M. J. Reid ◽  
E. M. L. Humphreys ◽  
C. Henkel ◽  
J. J. Condon ◽  
...  
Keyword(s):  
Angular Diameter ◽  
Angular Diameter Distance

scholarly journals Analysis of the Angular Dependence of Time Delay in Gravitational Lensing

2018 ◽  
Author(s):  
Nicola Alchera ◽  
Marco Bonici ◽  
Roberta Cardinale ◽  
Alba Domi ◽  
Nicola Maggiore ◽  
...  
Keyword(s):  
Time Delay ◽  
Angular Dependence ◽  
Gravitational Potential ◽  
Gravitational Lensing ◽  
Degrees Of Freedom ◽  
Hubble Constant ◽  
Smoothness Condition ◽  
Central Potential ◽  
Alternative Formula

We consider an alternative formula for time delay in gravitational lensing. Imposing a smoothness condition on the gravitationally deformed paths followed by the photons from the source to the observer, we show that our formula displays the same degrees of freedom of the standard one. In addition to this, it is shown that the standard expression for time delay is recovered when small angles are involved. These two features strongly support the claim that the formula for time delay studied in this paper is the generalization to arbitrary angles of the standard one, which is valid at small angles. This could therefore result in a useful tool in view of softening the known discrepancy between the various estimates of the Hubble constant. As an aside, two interesting consequences of our proposal for time delay are discussed: the existence of a constraint on the gravitational potential generated by the lens and a formula for the mass of the lens in the case of central potential.

scholarly journals Light propagation and optical scalars in torsion theories of gravity

2019 ◽  
Vol 34 (04) ◽  
pp. 1950029
Author(s):  
Siamak Akhshabi
Keyword(s):  
Gravitational Lensing ◽  
Light Propagation ◽  
Raychaudhuri Equation ◽  
Angular Diameter Distance ◽  
Propagation Of Light ◽  
Light Rays ◽  
Theories Of Gravity ◽  
Torsion Theories ◽  
Basic Equations ◽  
Gauge Theory Of Gravity

We investigate the propagation of light rays and evolution of optical scalars in gauge theories of gravity where torsion is present. Recently, the modified Raychaudhuri equation in the presence of torsion has been derived. We use this result to derive the basic equations of geometric optics for several different interesting solutions of the Poincaré gauge theory of gravity. The results show that the focusing effects for neighboring light rays will be different than general relativity. This in turn has practical consequences in the study of gravitational lensing effects and also in determining the angular diameter distance for cosmological objects.

scholarly journals Dark Energy Survey Year 1 results: measurement of the baryon acoustic oscillation scale in the distribution of galaxies to redshift 1

2018 ◽  
Vol 483 (4) ◽  
pp. 4866-4883 ◽  
Author(s):  
T M C Abbott ◽  
F B Abdalla ◽  
A Alarcon ◽  
S Allam ◽  
F Andrade-Oliveira ◽  
...  
Keyword(s):  
Dark Energy ◽  
Cold Dark Matter ◽  
Angular Diameter ◽  
Acoustic Oscillations ◽  
Distance Measurements ◽  
Angular Diameter Distance ◽  
Dark Energy Survey ◽  
Trade Offs ◽  
Physical Scale ◽  
Energy Survey

ABSTRACT We present angular diameter distance measurements obtained by locating the baryon acoustic oscillations (BAO) scale in the distribution of galaxies selected from the first year of Dark Energy Survey data. We consider a sample of over 1.3 million galaxies distributed over a footprint of 1336 deg2 with 0.6 < $z$photo < 1 and a typical redshift uncertainty of 0.03(1 + $z$). This sample was selected, as fully described in a companion paper, using a colour/magnitude selection that optimizes trade-offs between number density and redshift uncertainty. We investigate the BAO signal in the projected clustering using three conventions, the angular separation, the comoving transverse separation, and spherical harmonics. Further, we compare results obtained from template-based and machine-learning photometric redshift determinations. We use 1800 simulations that approximate our sample in order to produce covariance matrices and allow us to validate our distance scale measurement methodology. We measure the angular diameter distance, DA, at the effective redshift of our sample divided by the true physical scale of the BAO feature, rd. We obtain close to a 4 per cent distance measurement of DA($z$eff = 0.81)/rd = 10.75 ± 0.43. These results are consistent with the flat Λ cold dark matter concordance cosmological model supported by numerous other recent experimental results.

scholarly journals The failure of testing for cosmic opacity via the distance-duality relation

2020 ◽  
Vol 497 (1) ◽  
pp. 378-388
Author(s):  
Václav Vavryčuk ◽  
Pavel Kroupa
Keyword(s):  
Cosmological Model ◽  
Convincing Evidence ◽  
Duality Relation ◽  
Angular Diameter ◽  
Luminosity Distance ◽  
Angular Diameter Distance ◽  
Frequency Independent ◽  
Unique Interpretation ◽  
The Universe

ABSTRACT The distance-duality relation (DDR) between the luminosity distance DL and the angular diameter distance DA is viewed as a powerful tool for testing for the opacity of the Universe, being independent of any cosmological model. It was applied by many authors, who mostly confirm its validity and report a negligible opacity of the Universe. Nevertheless, a thorough analysis reveals that applying the DDR in cosmic opacity tests is tricky. Its applicability is strongly limited because of a non-unique interpretation of the DL data in terms of cosmic opacity and a rather low accuracy and deficient extent of currently available DA data. Moreover, authors usually assume that cosmic opacity is frequency independent and parametrize it in their tests by a prescribed phenomenological function. In this way, they only prove that cosmic opacity does not follow their assumptions. As a consequence, no convincing evidence of transparency of the universe using the DDR has so far been presented.

Time delay due to spin and gravitational lensing

2002 ◽  
Vol 19 (15) ◽  
pp. 3863-3874 ◽  
Author(s):  
I Ciufolini ◽  
F Ricci
Keyword(s):  
Time Delay ◽  
Gravitational Lensing

scholarly journals STRIDES: a 3.9 per cent measurement of the Hubble constant from the strong lens system DES J0408−5354

2020 ◽  
Vol 494 (4) ◽  
pp. 6072-6102 ◽  
Author(s):  
A J Shajib ◽  
S Birrer ◽  
T Treu ◽  
A Agnello ◽  
E J Buckley-Geer ◽  
...  
Keyword(s):  
Time Delay ◽  
Hubble Space Telescope ◽  
Hubble Constant ◽  
Lens System ◽  
Microwave Background ◽  
Angular Diameter Distance ◽  
Measured Time ◽  
Local Distance ◽  
Previous Sample ◽  
The Cost

ABSTRACT We present a blind time-delay cosmographic analysis for the lens system DES J0408−5354. This system is extraordinary for the presence of two sets of multiple images at different redshifts, which provide the opportunity to obtain more information at the cost of increased modelling complexity with respect to previously analysed systems. We perform detailed modelling of the mass distribution for this lens system using three band Hubble Space Telescope imaging. We combine the measured time delays, line-of-sight central velocity dispersion of the deflector, and statistically constrained external convergence with our lens models to estimate two cosmological distances. We measure the ‘effective’ time-delay distance corresponding to the redshifts of the deflector and the lensed quasar $D_{\Delta t}^{\rm eff}=$$3382_{-115}^{+146}$ Mpc and the angular diameter distance to the deflector Dd = $1711_{-280}^{+376}$ Mpc, with covariance between the two distances. From these constraints on the cosmological distances, we infer the Hubble constant H0= $74.2_{-3.0}^{+2.7}$ km s−1 Mpc−1 assuming a flat ΛCDM cosmology and a uniform prior for Ωm as $\Omega _{\rm m} \sim \mathcal {U}(0.05, 0.5)$. This measurement gives the most precise constraint on H0 to date from a single lens. Our measurement is consistent with that obtained from the previous sample of six lenses analysed by the H0 Lenses in COSMOGRAIL’s Wellspring (H0LiCOW) collaboration. It is also consistent with measurements of H0 based on the local distance ladder, reinforcing the tension with the inference from early Universe probes, for example, with 2.2σ discrepancy from the cosmic microwave background measurement.

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