Cosmic Ray Events and Natural Radioactivity in CCD Cryostats

Florentin-Nielsen, R.; Andersen, M. I.; Nielsen, Sven Poul

doi:10.1007/978-94-011-0383-1_26

Cited by 15 publications

(9 citation statements)

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“…The first time delay for the gravitational lens Q0957+561 was measured in 1984 (Florentin-Nielsen 1984), and since then more than 11 time delay lenses have been found, including seven systems with a good quality of astrometric data and two systems with serious problems (Kochanek & Schechter 2004). It would be very interesting if those debatable systems could be explained in the framework of TeVeS.…”

Section: Discussionmentioning

confidence: 99%

Theoretical Aspects of Gravitational Lensing in TeVeS

Chiu

Tian

2006

ApJ

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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.

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Section: Discussionmentioning

confidence: 99%

Theoretical Aspects of Gravitational Lensing in TeVeS

Chiu

Tian

2006

ApJ

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“…-Florentin-Nielsen (1984), 5 yr, 50 dates, 1.55 H 0.1; Vanderriest et al (1989), 8 yr, 131 dates, 1.14 H 0.05; Beskin & Oknyanskij (1992), 8 yr, 127 dates, 1.43 H 0.04; Press, Rybicki, & Hewitt (1992a), 8 yr, 127 dates, 1.47 H 0.04;andPelt et al (1994), 8 yr, 127 dates, 1.14. r band.-Schild &Cholfin (1986), 4 yr, 29 dates, 1.03 H 0.1; Schild (1990), 9 yr, 373 dates, 1.11 H 0.03; Beskin & Oknyanskij (1992), 9 yr, 373 dates, 1.41 H 0.04; and Kundić et al (1995, hereafter K95), 1 yr, 183 exposures.…”

Section: Introductionmentioning

confidence: 97%

Optical Photometry of Quasar 0957+561A, B

Oscoz

Serra-Ricart

Goicoechea

et al. 1996

The Astrophysical Journal

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Observations of the gravitational lens system 0957ϩ561A, B in the R band are presented in this Letter. The observations, taken with the 82 cm IAC-80 telescope, at Teide Observatory, Spain, were made from the beginning of 1996 February to June, as part of an on-going lens monitoring program to obtain the time delay between the two components of the system. By comparing our data with those previously published by Kundić et al., we infer that a large delay (Ͼ500 days) is inconsistent with both data sets.

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“…Shortly after the discovery, changes in brightness of the two quasar images were detected and measured by several groups (Lloyd 1981;Miller, Antonucci & Keel 1981;Keel 1982;Schild & Weekes 1984;Schild & Chol n 1986). The double quasar 0957+561A, B was also the rst system for which an attempt to measure the time delay was reported see, e.g., Dyer & Roeder (1980) or Florentin-Nielsen (1984)]. Since the gravitational time delay is inversely proportional to the Hubble parameter H 0 (Refsdal, 1964), it can be in principle used to determine H 0 .…”

Section: Introductionmentioning

confidence: 99%

An Event in the Light Curve of 0957+561A and Prediction of the 1996 Image B Light Curve

Kundić

Colley

Gott

et al. 1995

The Astrophysical Journal

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CCD photometry of the gravitational lens system 0957+561A,B in the g and r bands was obtained on alternate nights, weather permitting, from December 1994 through May 1995 using the Double Imaging Spectrograph (DIS) on the Apache Point Observatory (APO) 3.5-meter telescope. The remote observing and fast instrument change capabilities of this facility allowed accumulation of light curves sampled frequently and consistently. The Honeycutt ensemble photometry algorithm was applied to the data set and yielded typical relative photometric errors of approximately 0.01 magnitudes. Image A exhibited a sharp drop of about 0.1 magnitudes in late December 1994; no other strong features were recorded in either image. This event displays none of the expected generic features of a microlensing-induced ux variation and is likely to be intrinsic to the quasar; if so, it should also be seen in the B image with the lensing di erential time delay. We give the expected 1996 image B light curves based on two values of the time delay and brightness ratio which have been proposed and debated in the literature. Continued monitoring of the system in the rst half of 1996 should easily detect the image B event and thus resolve the time-delay controversy.

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Cosmic Ray Events and Natural Radioactivity in CCD Cryostats

Cited by 15 publications

References 0 publications

Theoretical Aspects of Gravitational Lensing in TeVeS

Theoretical Aspects of Gravitational Lensing in TeVeS

Optical Photometry of Quasar 0957+561A, B

An Event in the Light Curve of 0957+561A and Prediction of the 1996 Image B Light Curve

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