scholarly journals Constraints on Lorentz invariance and CPT violation using optical photometry and polarimetry of active galaxies BL Lacertae and S5 B0716+714

2019 ◽  
Vol 99 (3) ◽  
Author(s):  
Andrew S. Friedman ◽  
David Leon ◽  
Kevin D. Crowley ◽  
Delwin Johnson ◽  
Grant Teply ◽  
...  
Keyword(s):  
Lorentz Invariance ◽  
Active Galaxies ◽  
Cpt Violation ◽  
Optical Photometry ◽  
Bl Lacertae

scholarly journals CPT violation does not lead to violation of Lorentz invariance and vice versa

2011 ◽  
Vol 699 (3) ◽  
pp. 177-180 ◽  
Author(s):  
Masud Chaichian ◽  
Alexander D. Dolgov ◽  
Victor A. Novikov ◽  
Anca Tureanu
Keyword(s):  
Lorentz Invariance ◽  
Cpt Violation ◽  
Violation Of Lorentz Invariance

scholarly journals High-Energy Gamma-Ray Observations of Active Galaxies

1994 ◽  
Vol 142 ◽  
pp. 917-922
Author(s):  
Carl E. Fichtel
Keyword(s):  
Gamma Ray ◽  
Seyfert Galaxies ◽  
High Energy ◽  
Active Galaxies ◽  
Bl Lacertae ◽  
High Energy Gamma ◽  
Large Numbers ◽  
Wide Range ◽  
Energy Gamma ◽  
Time Variations

AbstractDuring the period from 1992 May to early 1992 November, the Energetic Gamma-Ray Experiment Telescope (EGRET) on board the Compton Gamma Ray Observatory obtained high-energy gamma-ray data for most of the sky. A total of 18 active galaxies have been seen with high certainty, and it is expected that more will be found in the data when a more thorough analysis is complete. All of those that have been seen are radio-loud quasars or BL Lacertae objects; most have already been identified as blazars. No Seyfert galaxies have been found thus far. If the spectra are represented as a power law in energy, spectral slopes ranging from approximately −1.7 to −2.4 are found. A wide range of z-values exists in the observed sample, eight having values in excess of 1.0. Time variations have been seen, with the timescale for a significant change being as short as days in at least one case. These results imply the existence of very large numbers of relativistic particles, probably close to the central object. Although a large extrapolation is required, their existence also suggests that these active galactic nuclei may be the source of the extragalactic cosmic rays.Subject headings: acceleration of particles — galaxies: active — gamma rays: observations — quasars: general

scholarly journals Improved constraints on anisotropic birefringent Lorentz invariance and CPT violation from broadband optical polarimetry of high redshift galaxies

2020 ◽  
Vol 102 (4) ◽  
Author(s):  
Andrew S. Friedman ◽  
Roman Gerasimov ◽  
David Leon ◽  
Walker Stevens ◽  
David Tytler ◽  
...  
Keyword(s):  
Lorentz Invariance ◽  
High Redshift ◽  
Cpt Violation ◽  
High Redshift Galaxies ◽  
Redshift Galaxies

scholarly journals Long-term and intra-day variability of BL Lacertae since the last great outburst

2006 ◽  
Vol 2 (S238) ◽  
pp. 419-420 ◽  
Author(s):  
Maria G. Nikolashvili ◽  
Omar M. Kurtanidze
Keyword(s):  
Ccd Camera ◽  
Active Phase ◽  
Optical Variability ◽  
Optical Photometry ◽  
Bl Lacertae ◽  
Maximum Variation

AbstractWe present the results of optical photometry of BL Lacertae carried out using ST-6 CCD camera attached to the Newtonian focus of the 70 cm meniscus telescope of Abastumani Observatory. On the basis of observations conducted since August 1997 during more than 550 nights about 17000 frames were collected. They have been reduced using Daophot II.It has been shown that optical variability of BL Lacertae is very complex. The maximum variation was observed at long-term scale and is equal to equals to 3.0 mag (rms=0.03) in B band, while the variation in V and R bands are within 2.71 mag (0.02) and 2.53 mag (0.01), respectively. This means that variations are larger at shorter wavelength or the object become bluer in the active phase. It were also demonstrated that BL Lacertae shows intra-day variability within 0.30 mag (0.02), while intra-hour variability within 0.10 mag (0.01) magnitudes.

Radio‐loud Active Galaxies in the Northern ROSAT All‐Sky Survey. III. New Spectroscopic Identifications from the RASS–Green Bank BL Lacertae Survey

1998 ◽  
Vol 118 (1) ◽  
pp. 127-175 ◽  
Author(s):  
S. A. Laurent‐Muehleisen ◽  
R. I. Kollgaard ◽  
R. Ciardullo ◽  
E. D. Feigelson ◽  
W. Brinkmann ◽  
...  
Keyword(s):  
Active Galaxies ◽  
Bl Lacertae ◽  
Sky Survey

Nonlocal Gravity

2017 ◽  
Author(s):  
Bahram Mashhoon
Keyword(s):  
Gravitational Field ◽  
Gravitational Lensing ◽  
Past History ◽  
Lorentz Invariance ◽  
Minkowski Spacetime ◽  
Field Measurements ◽  
Local Principle ◽  
History Of ◽  
Expansion Of The Universe ◽  
Nearby Galaxies

A postulate of locality permeates through the special and general theories of relativity. First, Lorentz invariance is extended in a pointwise manner to actual, namely, accelerated observers in Minkowski spacetime. This hypothesis of locality is then employed crucially in Einstein’s local principle of equivalence to render observers pointwise inertial in a gravitational field. Field measurements are intrinsically nonlocal, however. To go beyond the locality postulate in Minkowski spacetime, the past history of the accelerated observer must be taken into account in accordance with the Bohr-Rosenfeld principle. The observer in general carries the memory of its past acceleration. The deep connection between inertia and gravitation suggests that gravity could be nonlocal as well and in nonlocal gravity the fading gravitational memory of past events must then be taken into account. Along this line of thought, a classical nonlocal generalization of Einstein’s theory of gravitation has recently been developed. In this nonlocal gravity (NLG) theory, the gravitational field is local, but satisfies a partial integro-differential field equation. A significant observational consequence of this theory is that the nonlocal aspect of gravity appears to simulate dark matter. The implications of NLG are explored in this book for gravitational lensing, gravitational radiation, the gravitational physics of the Solar System and the internal dynamics of nearby galaxies as well as clusters of galaxies. This approach is extended to nonlocal Newtonian cosmology, where the attraction of gravity fades with the expansion of the universe. Thus far only some of the consequences of NLG have been compared with observation.

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