Commencement Address

Commencement address given by Arno A. Penzias, Vice President of Research at AT&T Bell Laboratories, to the Winter 1988 graduating class of The Ohio State University, St. John Arena, Columbus, Ohio, March 18, 1988

The molecular cloud Sagittarius B2

The structure of the Sgr B2 molecular cloud has been studied by detailed and extensive mappings of the CO, ^(13)CO, CS, and H_2CO (2-cm) transitions. The cloud consists of a dense core at the OH maser position plus a very large envelope 45 pc across. Sagittarius B2 is one of the most massive objects in the Galaxy, containing about 3 x 10^6 M_⊙ - an estimate arrived at independently from calculated ^(13)CO column densities, from application of the virial theorem, and from far-infrared measurements. The molecular gas has an average temperature T_k of ~ 20 K; that this is similar to the temperature of grains emitting far-infrared radiation is taken as evidence of near thermal equilibrium between dust grains and H_2. The dynamics of the gas in the cloud is found to be dominated by large-scale systematic motions with velocity not a monotonic function of radius

The interstellar C18O/C17O ratio in the solar neighbourhood: The rho Oph cloud

Observations of up to ten carbon monoxide (CO and isotopomers) transitions are presented to study the interstellar C18O/C17O ratio towards 21 positions in the nearby (d~140pc) low-mass star forming cloud rho Oph. A map of the C18O J=1-0 distribution of parts of the cloud is also shown. An average 12C18O/12C17O isotopomeric ratio of 4.11 +/- 0.14, reflecting the 18O/17O isotope ratio, is derived from Large Velocity Gradient (LVG) calculations. From LTE column densities we derive a ratio of 4.17 +/-0.26. These calculations also show that the kinetic temperature decreases from about 30 K in the cloud envelope to about 10 K in the cloud cores. This decrease is accompanied by an increase of the average molecular hydrogen density from 10^4 cm-3 to >10^5 cm-3. Towards some lines of sight C18O optical depths reach values of order unity.Comment: 13 pages, 9 figures; accepted for publication in A&

Sources and budgets for CO and O-3 in the northeastern Pacific during the spring of 2001: Results from the PHOBEA-II Experiment

Abstract. Ground and airborne measurements of CO, ozone, and aerosols were obtained in th

Molecular Clouds in the Galactic Center Region: Carbon Monoxide Observations at 2.6 Millimeters

A preliminary CO emission line survey covering a strip at b = -2' from ℓ = 359°.7 to ℓ = 2°.8 is presented which shows a continuous band of emission connecting the region between Sgr A and Sgr B. A high-resolution map of the Sgr A cloud near the galactic center shows that there are at least two clouds centered within 3' of each other with a velocity difference of 35 km s^(-1). Measurement of the ^(13)C^(16)O and ^12)C^(18)O emission indicates isotopic abundances similar to those of the solar system

Arrival time and magnitude of airborne fission products from the Fukushima, Japan, reactor incident as measured in Seattle, WA, USA

We report results of air monitoring started due to the recent natural catastrophe on 11 March 2011 in Japan and the severe ensuing damage to the Fukushima Dai-ichi nuclear reactor complex. On 17-18 March 2011, we registered the first arrival of the airborne fission products 131-I, 132-I, 132-Te, 134-Cs, and 137-Cs in Seattle, WA, USA, by identifying their characteristic gamma rays using a germanium detector. We measured the evolution of the activities over a period of 23 days at the end of which the activities had mostly fallen below our detection limit. The highest detected activity amounted to 4.4 +/- 1.3 mBq/m^3 of 131-I on 19-20 March.Comment: 7 pages, 5 figures, published in Journal of Environmental Radioactivit

The molecular cloud Sagittarius B2

The structure of the Sgr B2 molecular cloud has been studied by detailed and extensive mappings of the CO, ^(13)CO, CS, and H_2CO (2-cm) transitions. The cloud consists of a dense core at the OH maser position plus a very large envelope 45 pc across. Sagittarius B2 is one of the most massive objects in the Galaxy, containing about 3 x 10^6 M_⊙ - an estimate arrived at independently from calculated ^(13)CO column densities, from application of the virial theorem, and from far-infrared measurements. The molecular gas has an average temperature T_k of ~ 20 K; that this is similar to the temperature of grains emitting far-infrared radiation is taken as evidence of near thermal equilibrium between dust grains and H_2. The dynamics of the gas in the cloud is found to be dominated by large-scale systematic motions with velocity not a monotonic function of radius

Singularity: Raychaudhuri Equation once again

I first recount Raychaudhuri's deep involvement with the singularity problem in general relativity. I then argue that precisely the same situation has arisen today in loop quantum cosmology as obtained when Raychaudhuri discovered his celebrated equation. We thus need a new analogue of the Raychaudhuri equation in quantum gravity.Comment: 11 pages, Contribution to Special issue of Pramana on Raychaudhuri Equation at Cross-roads, edited by Naresh Dadhich, Pankaj Joshi and Probir Ro

A quantum mechanical relation connecting time, temperature, and cosmological constant of the universe: Gamow's relation revisited as a special case

Considering our expanding universe as made up of gravitationally interacting particles which describe particles of luminous matter and dark matter and dark energy which is described by a repulsive harmonic potential among the points in the flat 3-space, we derive a quantum mechanical relation connecting, temperature of the cosmic microwave background radiation, age, and cosmological constant of the universe. When the cosmological constant is zero, we get back the Gamow's relation with a much better coefficient. Otherwise, our theory predicts a value of the cosmological constant $2.0 10^{-56} {\rm {cm^{-2}}}$ when the present values of cosmic microwave background temperature of 2.728 K and age of the universe 14 billion years are taken as input.Comment: 4 pages, 1 figure, Study of the Universe from a condensed matter point of view, section III corrected with a single body potentia