Research on Computational and Display Requirements for Human Control of Space Vehicle Boosters, Phase III. Part II - Computer Programs and Data Package Final Report, 1 Mar. - 31 Aug. 1967

Hybrid computer program for real time trajectory determination of human controlled space vehicle booste

The Department of Justice Versus Apple Inc. -- The Great Encryption Debate Between Privacy and National Security

This article is an attempt to objectively examine and assess legal arguments made by Apple Inc. (Apple) and the Department of Justice (DOJ) concerning the DOJ’s use of the All Writs Act[1] (AWA) to require Apple to provide technical assistance to the DOJ so that it could access the encrypted data from the locked iPhone of Syed Rizwan Farook, commonly referred to as the San Bernardino shooter. The DOJ’s initial ex parte application focused on meeting the requirements of United States v. New York Telephone Co.[2] concluding the court order was authorized and appropriate. Apple not only argued the court exceeded its authority under various theories (e.g., because the Political Question Doctrine and/or the Communications Assistance for Law Enforcement Act[3] (CALEA) applied), but also that the court violated the separation of powers doctrine and the First, Fourth, and Fifth Amendments of the U.S. Constitution. This article concludes the United States Government did not violate Apple’s First, Fourth and Fifth Amendment rights as writing code only instructs a computer how to function, therefore is not speech under the First Amendment; the FBI obtained a probable case search warrant and the owner of the device consented to the FBI’s search of the device; and Apple had not been denied its constitutional liberties, and had been given notice and an opportunity to be heard. In addition, given the personal nature of privacy rights under the Fourth Amendment and the common law, Apple is unable to assert either of those rights on behalf of third-parties. As to Apple asserting a violation of iPhone users’ constitutional right to privacy under the legal theory of jus tertii, it is unlikely Apple would be able to meet the legal requirements of jus tertii as the injury-in-fact to individual iPhones users is too speculative. This article also concludes the Political Question Doctrine does not apply nor does CALEA apply as the statute is limited to data in motion while the encrypted data is data at rest. Furthermore, this article concludes the court did not exceed its jurisdictional authority when it issued the order nor was there a violation of the separation of powers doctrine given the court’s underlying jurisdictional authority of the probable cause search warrant. And, given this underlying jurisdictional authority and the AWA’s 215-plus years of history, the focus of the DOJ–Apple dispute centers on whether the court properly analyzed the three elements articulated in N.Y. Telephone Co.for requiring third party assistance. This article concludes the DOJ has the stronger argument for two of the three elements in that Apple is not too far removed from the matter and Apple’s assistance is necessary. Ultimately, the article determines the primary legal issue centers on the second element and whether the order is burdensome or unreasonable. This issue is directly tied to the question whether the order requires Apple to create a backdoor, a master key, and/or something equivalent to a master key. Because neither party provides definitions and the Declarations lack clarity as to how significant the modification to the Government Operating System/Software Image File (GovtOS/SIF) must be in order for it to work on other iPhones, it cannot be determined whether the order is unreasonable or burdensome. In order to resolve this issue, additional information is required, to include an accepted definition of backdoor and master key and the extent of the modifications to GovtOS/SIF such that it would work on other iPhones. [1] 28 U.S.C. § 1651 (2015). [2] United States v. N. Y. Tel. Co., 434 U.S. 159, 169 (1977). [3] 47 U.S.C. §§ 1001-1010 (2015)

Squeezars: Tidally powered stars orbiting a massive black hole

We propose that there exists a class of transient sources, "squeezars", which are stars caught in highly eccentric orbits around a massive (m<10^8 Mo) black hole (MBH), whose atypically high luminosity (up to a significant fraction of their Eddington luminosity) is powered by tidal interactions with the MBH. Their existence follows from the presence of a mass sink, the MBH, in the galactic center, which drives a flow of stars into nearly radial orbits to replace those it has destroyed. We consider two limits for the stellar response to tidal heating: surface heating with radiative cooling ("hot squeezars") and bulk heating with adiabatic expansion ("cold squeezars"), and calculate the evolution of the squeezar orbit, size, luminosity and effective temperature. The squeezar formation rate is only ~0.05 that of tidal disruption flares, but squeezar lifetimes are many orders of magnitude longer, and so future observations of squeezars in nearby galaxies can probe the tidal process that feeds MBHs and the effects of extreme tides on stars. The mean number of squeezars orbiting the Galactic MBH is estimated at 0.1-1.Comment: ApJ Lett. accepted. 4 pp. 1 fi

Multiwavelength VLBI observations of Sagittarius A*

The compact radio source Sgr\,A*, associated with the super massive black hole at the center of the Galaxy, has been studied with VLBA observations at 3 frequencies (22, 43, 86\,GHz) performed on 10 consecutive days in May 2007. The total VLBI flux density of Sgr\,A* varies from day to day. The variability is correlated at the 3 observing frequencies with higher variability amplitudes appearing at the higher frequencies. For the modulation indices, we find 8.4\,% at 22\,GHz, 9.3\,% at 43\,GHz, and 15.5\,% at 86\,GHz. The radio spectrum is inverted between 22 and 86\,GHz, suggesting inhomogeneous synchrotron self-absorption with a turnover frequency at or above 86\,GHz. The radio spectral index correlates with the flux density, which is harder (more inverted spectrum) when the source is brighter. The average source size does not appear to be variable over the 10-day observing interval. However, we see a tendency for the sizes of the minor axis to increase with increasing total flux, whereas the major axis remains constant. Towards higher frequencies, the position angle of the elliptical Gaussian increases, indicative of intrinsic structure, which begins to dominate the scatter broadening. At cm-wavelength, the source size varies with wavelength as $\lambda^{2.12\pm0.12}$, which is interpreted as the result of interstellar scatter broadening. After removal of this scatter broadening, the intrinsic source size varies as $\lambda^{1.4 ... 1.5}$. The VLBI closure phases at 22, 43, and 86\,GHz are zero within a few degrees, indicating a symmetric or point-like source structure. In the context of an expanding plasmon model, we obtain an upper limit of the expansion velocity of about 0.1\,c from the non-variable VLBI structure. This agrees with the velocity range derived from the radiation transport modeling of the flares from the radio to NIR wavelengths.}Comment: 14pages, 14 Figures, Accepted for publication in A&

Coordinated NIR/mm observations of flare emission from Sagittarius A*

We report on a successful, simultaneous observation and modelling of the millimeter (mm) to near-infrared (NIR) flare emission of the Sgr A* counterpart associated with the supermassive black hole at the Galactic centre (GC). We present a mm/sub-mm light curve of Sgr A* with one of the highest quality continuous time coverages and study and model the physical processes giving rise to the variable emission of Sgr A*.Comment: 14 pages, 16 figure

Astrometry of circumstellar masers

The circumstellar masers around evolved stars offer an interesting possibility to measure stellar parameters through VLBI astrometry. In this paper the application of this technique is discussed, including the accuracy and the uncertainties of the method. The different maser species (OH, H_2O, SiO) have slightly different characteristics and applications. This paper does not concern astrometry of maser spots to study the kinematics of the envelope, but concentrates on attempting to measure the motion of the underlying star.Comment: 8 pages, 2 figures, to appear in "Mass-losing Stars and their Circumstellar Matter", eds Y. Nakada & M. Honma, Kluwer ASSL serie

Simultaneous NIR/sub-mm observation of flare emission from SgrA*

We report on a successful, simultaneous observation and modeling of the sub-millimeter to near-infrared flare emission of the Sgr A* counterpart associated with the super-massive black hole at the Galactic center. Our modeling is based on simultaneous observations that have been carried out on 03 June, 2008 using the NACO adaptive optics (AO) instrument at the ESO VLT and the LABOCA bolometer at the APEX telescope. Inspection and modeling of the light curves show that the sub-mm follows the NIR emission with a delay of 1.5+/-0.5 hours. We explain the flare emission delay by an adiabatic expansion of the source components.Comment: 12 pages, 9 figures, 3 tables, in press with A&