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Articles 1 - 30 of 76
Full-Text Articles in Astrophysics and Astronomy
Studying The Impact Of The Geospace Environment On Solar Lithosphere Coupling And Earthquake Activity, Dimitar Ouzounov, Galina Khachikyan
Studying The Impact Of The Geospace Environment On Solar Lithosphere Coupling And Earthquake Activity, Dimitar Ouzounov, Galina Khachikyan
Mathematics, Physics, and Computer Science Faculty Articles and Research
In solar–terrestrial physics, there is an open question: does a geomagnetic storm affect earthquakes? We expand research in this direction, analyzing the seismic situation after geomagnetic storms (GMs) accompanied by the precipitation of relativistic electrons from the outer radiation belt to form an additional radiation belt (RB) around lower geomagnetic lines. We consider four widely discussed cases in the literature for long-lived (weeks, months) RBs due to GMs and revealed that the 1/GMs 24 March 1991 with a new RB at L~2.6 was followed by an M7.0 earthquake in Alaska, 30 May 1991, near footprint L = 2.69; the 2/GMs …
Black Holes, Disk Structures, And Cosmological Implications In E-Dimensional Space, Subhash Kak, Menas C. Kafatos
Black Holes, Disk Structures, And Cosmological Implications In E-Dimensional Space, Subhash Kak, Menas C. Kafatos
Mathematics, Physics, and Computer Science Faculty Articles and Research
We examine a modern view of the universe that builds on achieved successes of quantum mechanics, general relativity, and information theory, bringing them together in integrated approach that is founded on the realization that space itself is e-dimensional. The global and local implications of noninteger dimensionality are examined, and how it may have increased from the value of zero to its current value is investigated. We find surprising aspects that tie to structures in the universe, black holes, and the role of observations.
Knotty Inflation And The Dimensionality Of Spacetime, Arjun Berera, Roman V. Buniy, Thomas W. Kephart, Heinrich Päs, João G. Rosa
Knotty Inflation And The Dimensionality Of Spacetime, Arjun Berera, Roman V. Buniy, Thomas W. Kephart, Heinrich Päs, João G. Rosa
Mathematics, Physics, and Computer Science Faculty Articles and Research
We suggest a structure for the vacuum comprised of a network of tightly knotted/linked flux tubes formed in a QCD-like cosmological phase transition and show that such a network can drive cosmological inflation. As the network can be topologically stable only in three space dimensions, this scenario provides a dynamical explanation for the existence of exactly three large spatial dimensions in our Universe.
Closed String Thermodynamics And A Blue Tensor Spectrum, Robert H. Brandenberger, Ali Nayeri, Subodh P. Patil
Closed String Thermodynamics And A Blue Tensor Spectrum, Robert H. Brandenberger, Ali Nayeri, Subodh P. Patil
Mathematics, Physics, and Computer Science Faculty Articles and Research
The BICEP-2 team has recently reported the positive detection of cosmic microwave background Bmode polarization. Although uncertainties due to galactic dust foregrounds remain, it is a constructive exercise to work out the implications of presuming some part of the detected B-mode signal to be due to primordial gravitational waves. Were a positive detection of a tensor-to-scalar ratio larger than r greater than or similar to O(10(-2)) confirmed, detecting a tilt in the tensor spectrum comparable to that observed for the scalar power spectrum becomes in principle possible. We wish to explore in this brief paper the possibility of there being …
Elvis: Exploring The Local Volume In Simulations, Shea Garrison-Kimmel, Michael Boylan-Kolchin, James S. Bullock, Kyle Lee
Elvis: Exploring The Local Volume In Simulations, Shea Garrison-Kimmel, Michael Boylan-Kolchin, James S. Bullock, Kyle Lee
Mathematics, Physics, and Computer Science Faculty Articles and Research
We introduce a set of high-resolution dissipationless simulations that model the Local Group (LG) in a cosmological context: Exploring the Local Volume in Simulations (ELVIS). The suite contains 48 Galaxy-size haloes, each within high-resolution volumes that span 2-5 Mpc in size, and each resolving thousands of systems with masses below the atomic cooling limit. Half of the ELVIS galaxy haloes are in paired configurations similar to the Milky Way (MW) and M31; the other half are isolated, mass-matched analogues. We find no difference in the abundance or kinematics of substructure within the virial radii of isolated versus paired hosts. On …
Practical Approach To Cosmological Perturbations In Modified Gravity, Alessandra Silvestri, Levon Pogosian, Roman V. Buniy
Practical Approach To Cosmological Perturbations In Modified Gravity, Alessandra Silvestri, Levon Pogosian, Roman V. Buniy
Mathematics, Physics, and Computer Science Faculty Articles and Research
The next generation of large scale surveys will not only measure cosmological parameters within the framework of general relativity, but will also allow for precision tests of the framework itself. At the order of linear perturbations, departures from the growth in the standard cosmological model can be quantified in terms of two functions of time and Fourier number k. We argue that in local theories of gravity, in the quasistatic approximation, these functions must be ratios of polynomials in k, with the numerator of one function being equal to the denominator of the other. Moreover, the polynomials are even and …
Everything Is Entangled, Roman V. Buniy, Stephen D. H. Hsu
Everything Is Entangled, Roman V. Buniy, Stephen D. H. Hsu
Mathematics, Physics, and Computer Science Faculty Articles and Research
We show that big bang cosmology implies a high degree of entanglement of particles in the universe. In fact, a typical particle is entangled with many particles far outside our horizon. However, the entanglement is spread nearly uniformly so that two randomly chosen particles are unlikely to be directly entangled with each other - the reduced density matrix describing any pair is likely to be separable.
Toward Solving The Cosmological Constant Problem By Embedding, Roman V. Buniy, Thomas W. Kephart
Toward Solving The Cosmological Constant Problem By Embedding, Roman V. Buniy, Thomas W. Kephart
Mathematics, Physics, and Computer Science Faculty Articles and Research
The typical scalar field theory has a cosmological constant problem. We propose a generic mechanism by which this problem is avoided at tree level by embedding the theory into a larger theory. The metric and the scalar field coupling constants in the original theory do not need to be fine-tuned, while the extra scalar field parameters and the metric associated with the extended theory are fine-tuned dynamically. Hence, no fine-tuning of parameters in the full Lagrangian is needed for the vacuum energy in the new physical system to vanish at tree level. The cosmological constant problem can be solved if …
Superluminal Neutrinos At Opera Confront Pion Decay Kinematics, Ramanath Cowsick, Shmuel Nussinov, Utpal Sarkar
Superluminal Neutrinos At Opera Confront Pion Decay Kinematics, Ramanath Cowsick, Shmuel Nussinov, Utpal Sarkar
Mathematics, Physics, and Computer Science Faculty Articles and Research
Violation of Lorentz invariance (VLI) has been suggested as an explanation of the superluminal velocities of muon neutrinos reported by OPERA. In this Letter, we show that the amount of VLI required to explain this result poses severe difficulties with the kinematics of the pion decay, extending its lifetime and reducing the momentum carried away by the neutrinos. We show that the OPERA experiment limits alpha = (upsilon(v) - c)/c < 4 x 10(-6). We then take recourse to cosmic-ray data on the spectrum of muons and neutrinos generated in Earth's atmosphere to provide a stronger bound on VLI: (upsilon - c)/c < 10(-12).
Limit On Continuous Neutrino Emission From Neutron Stars, Itzhak Goldman, Shmuel Nussinov
Limit On Continuous Neutrino Emission From Neutron Stars, Itzhak Goldman, Shmuel Nussinov
Mathematics, Physics, and Computer Science Faculty Articles and Research
The timing data of the binary pulsar PSR1913+16, are used to establish an upper limit on the rate of continuous neutrino emission from neutron stars. Neutrino emission from each of the neutron stars of the binary system, increases the star binding energy and thus translates to a decrease in their masses. This in turn implies an increase with time of the binary period. Using the pulsar data we obtain an upper limit on the allowed rate of mass reduction: vertical bar M vertical bar < 1.1 x 10(-12) yr(-1) M, where M is the total mass of the binary. This constrains exotic nuclear equations of state that predict continuous neutrino emissions. The limit applies also to other channels of energy loss, e. g. axion emission. Continued timing measurements of additional binary pulsars, should yield a stronger limit in the future.
Can Large Scintillators Be Used For Solar-Axion Searches To Test The Cosmological Axion-Photon Oscillation Proposal?, F. T. Avignone Iii, R. J. Creswick, Shmuel Nussinov
Can Large Scintillators Be Used For Solar-Axion Searches To Test The Cosmological Axion-Photon Oscillation Proposal?, F. T. Avignone Iii, R. J. Creswick, Shmuel Nussinov
Mathematics, Physics, and Computer Science Faculty Articles and Research
Solar-axion interaction rates in Nal, Csl and Xe scintillators via the axio-electric effect were calculated. A table is presented with photo-electric and axio-electric cross sections, solar-axion fluxes, and the interaction rates from 2.0 to 10.0 keV. The results imply that annual-modulation data of large Nal and Csl arrays, and large Xe scintillation detectors, might be made sensitive enough to probe coupling to photons at levels required to explain axion-photon oscillation phenomena proposed to explain the survival of high-energy photons traveling cosmological distances. The DAMA/LIBRA data are used to demonstrate the power of the model-independent annual modulation due to the seasonal …
The Recent High State Of The Bl Lacertae Object Ao 0235 And Cross-Correlations Between Optical And Radio Bands, M. Roy, I. E. Papadikis, E. Ramos-Colon, R. Sambruna, K. Tsinganos, J. Papamastorkis, Menas Kafatos
The Recent High State Of The Bl Lacertae Object Ao 0235 And Cross-Correlations Between Optical And Radio Bands, M. Roy, I. E. Papadikis, E. Ramos-Colon, R. Sambruna, K. Tsinganos, J. Papamastorkis, Menas Kafatos
Mathematics, Physics, and Computer Science Faculty Articles and Research
We present new optical (B, V , R, I) and radio (at 14.5, 8.5, and 4.8 GHz) observations of the γ-ray- loud blazar AO 0235+164 obtained during the high state of 1997 December-1998 January. The data were combined with historical light curves from the literature to study correlated optical and radio variations over a time span of more than 20 years. Flux variability with large and energy-dependent amplitude is observed at both wave bands, with the source varying over all timescales sampled (years-months- days), in agreement with previous reports. We have performed a cross-correlation analysis of optical and radio light …
Contemporaneous Iue, Euve, And High-Energy Observations Of 3c 273, E. Ramos, Menas Kafatos, A. Fruscione, F. C. Bruhweiler, I. M. Mchardy, R. C. Hartman, L. G. Titarchuk, C. Von Montigny
Contemporaneous Iue, Euve, And High-Energy Observations Of 3c 273, E. Ramos, Menas Kafatos, A. Fruscione, F. C. Bruhweiler, I. M. Mchardy, R. C. Hartman, L. G. Titarchuk, C. Von Montigny
Mathematics, Physics, and Computer Science Faculty Articles and Research
We present the results of our 1994 January and 1995 January observations of the quasar 3C 273 obtained with the International Ultraviolet Explorer (IUE) and the Extreme-Ultraviolet Explorer (EUV E). These observations were part of a large multiwavelength campaign to observe 3C 273 from radio through γ-rays. Our 1995 January photometric observations with the EUV E Lexan/B Deep Survey (DS) instrument indicate strong evidence for variability, at a 99% confidence level, during the 12 day observing period. We have utilized ROSAT PSPC soft X-ray power-law models to correlate with EUV E count rates. Besides variations in the normalization level between …
Multifrequency Studies, Menas Kafatos
Multifrequency Studies, Menas Kafatos
Mathematics, Physics, and Computer Science Faculty Articles and Research
The present report concerns the following projects 'Multifrequency observations of the BL Lacertae object MK 421"; "EUVE and multifrequency observations of the quasars 3C 273 and 3C 279"; "EUVE observations of the symbiotic star RAquarii"; and "Morphology of the local HI void and ionization of He in the local ISM". The common theme of the above projects is UV observations and analysis of a wide range of astrophysical classes or objects, from the diffuse interstellar medium, to symbiotic stars (R Aqr), to active galactic nuclei (AGNs). Understanding the local (primarily neutral hydrogen or HI) interstellar medium is of great importance …
Multiwavelength Blazar Studies, Menas Kafatos
Multiwavelength Blazar Studies, Menas Kafatos
Mathematics, Physics, and Computer Science Faculty Articles and Research
The present report concerns the following projects 'High energy emission from hot accretion disks from active galactic nuclei'; 'OSSE spectral timing and monitoring observations of Cygnus X- 1'; 'OSSE observations of blazars'; and 'Search for correlated time variations of bright EGRET blazars'. The most favored model for the central engine inAGNs is the supermassive black hole hypothesis (Rees 1978). The observed luminosities range from approx. 10 logical and 44-45 erg /s for objects such as Mk 421 and Seyferts to as much as approx. 10logical and 47 for powerful QSOs such as 3C 273 and 3C 279, a large fraction …
Lateral Shock Of The R Aquarii Jet, J. M. Hollis, J. A. Pedelty, Menas Kafatos
Lateral Shock Of The R Aquarii Jet, J. M. Hollis, J. A. Pedelty, Menas Kafatos
Mathematics, Physics, and Computer Science Faculty Articles and Research
The R Aqr jet was observed with the VLA B-configuration at two epochs separated by ~13.2 yr. Comparison of the resulting 6 cm continuum images show that the radio jet has undergone a lateral counterclockwise rotation of ~6-12 on the plane of the sky. The model of jet parcels on independent trajectories is difficult to reconcile with these observations and leads us to consider a path-oriented jet (i.e., younger parcels follow the same path as older parcels). Comparison of the most recent radio image with a nearly contemporaneous HST /FOC ultraviolet image at ~2330 A suggests that the ultraviolet emission …
Ion Viscosity Mediated By Tangled Magnetic Fields: An Application To Black Hole Accretion Disks, P. Subramanian, P. A. Becker, Menas Kafatos
Ion Viscosity Mediated By Tangled Magnetic Fields: An Application To Black Hole Accretion Disks, P. Subramanian, P. A. Becker, Menas Kafatos
Mathematics, Physics, and Computer Science Faculty Articles and Research
We examine the viscosity associated with the shear stress exerted by ions in the presence of a tangled magnetic field. As an application, we consider the effect of this mechanism on the structure of black hole accretion disks. We do not attempt to include a self-consistent description of the magnetic field. Instead, we assume the existence of a tangled field with coherence length λcob• which is the average distance between the magnetic "kinks" that scatter the particles. For simplicity, we assume that the field is self-similar, and take λcob to be a fixed fraction ξ of the local disk height …
Shock Study In Fully Relativistic Isothermal Flows. Ii, Ruixin Yang, Menas Kafatos
Shock Study In Fully Relativistic Isothermal Flows. Ii, Ruixin Yang, Menas Kafatos
Mathematics, Physics, and Computer Science Faculty Articles and Research
The isothermal shocks and their stabilities in fully relativistic accretion wedge flows onto black holes are studied. The jump condition across the shock is modified by the relativistic effects when the sound speed is comparable to the speed of light. With a new kind of instability analysis, it is found that only one of the two possible shocks is stable. The results are applied to the QPO behavior in galactic black hole candidates such as Cygnus X-1.
Implications Of Gamma-Ray Transparency Constraints In Blazars: Minimum Distances And Gamma-Ray Collimation, P. A. Becker, Menas Kafatos
Implications Of Gamma-Ray Transparency Constraints In Blazars: Minimum Distances And Gamma-Ray Collimation, P. A. Becker, Menas Kafatos
Mathematics, Physics, and Computer Science Faculty Articles and Research
We develop a general expression for the γ-γ absorption coefficient, αγγ, for γ-rays propagating in an arbitrary direction at an arbitrary point in space above an X-ray-emitting accretion disk. The X-ray intensity is assumed to vary as a power law in energy and radius between the outer disk radius, R0 , and the inner radius, Rm., which is the radius of marginal stability for a Schwarzschild black hole. We use our result for αγγ to calculate the γ-γ optical depth, Tγγ, for γ-rays created at height z and propagating at angle Φ relative to the disk axis, and we show …
Multiwavelength Observations Of Markarian 421 During A Tev/X-Ray Flare, D. J. Macomb, C. W. Akerlof, H. D. Aller, M. F. Aller, D. L. Bertsch, Menas Kafatos
Multiwavelength Observations Of Markarian 421 During A Tev/X-Ray Flare, D. J. Macomb, C. W. Akerlof, H. D. Aller, M. F. Aller, D. L. Bertsch, Menas Kafatos
Mathematics, Physics, and Computer Science Faculty Articles and Research
A Te V flare from the BL Lac object Mrk 421 was detected in May of 1994 by the Whipple Observatory air Cherenkov experiment during which the flux above 250 GeV increased by nearly an order of magnitude over a 2-day period. Contemporaneous observations by ASCA showed the X-ray flux to be in a very high state. We present these results, combined with the first ever simultaneous or nearly simultaneous observations at Ge V gamma-ray, UV, IR, mm, and radio energies for this nearest BL Lac object. While the GeV gamma-ray flux increased slightly, there is little evidence for variability …
Osse Observations In Blazars, K. Mcnaron-Brown, W. N. Johnson, G. V. Jung, R. L. Kinzer, J. D. Kurfess, M. S. Strickman, C. D. Dermer, D. A. Grabelsky, W. R. Purcell, M. P. Ulmer, Menas Kafatos, P. A. Becker, R. Staubert, M. Maisack
Osse Observations In Blazars, K. Mcnaron-Brown, W. N. Johnson, G. V. Jung, R. L. Kinzer, J. D. Kurfess, M. S. Strickman, C. D. Dermer, D. A. Grabelsky, W. R. Purcell, M. P. Ulmer, Menas Kafatos, P. A. Becker, R. Staubert, M. Maisack
Mathematics, Physics, and Computer Science Faculty Articles and Research
Results are reported on observations obtained with the Oriented Scintillation Spectrometer Experiment (OSSE) instrument on the Compton Gamma Ray Observatory (CGRO) of 17 active galactic nuclei (AGNs) known to exhibit blazar properties at other wavelengths. These observations span the period from 1991 June through 1994 May. Of the 33 high-confidence EGRET detections of blazars during CGRO observing phases 1 and 2 (1991 May 16-1993 September 7), OSSE has observed eight and detected five, namely 3C 273, 3C 279, PKS 0528+134, CTA 102, and 3C 454.3. Additionally, OSSE has detected the BL Lac sources H1517+65.6 and PKS 2155-304, which were not …
Ultraviolet Temporal Variability Of The Peculiar Star R Aquarii, S. R. Meier, Menas Kafatos
Ultraviolet Temporal Variability Of The Peculiar Star R Aquarii, S. R. Meier, Menas Kafatos
Mathematics, Physics, and Computer Science Faculty Articles and Research
This paper is a comprehensive study of all far-UV spectra obtained with the International Ultraviolet Explorer (IUE) satellite of the symbiotic star R Aquarii (R Aqr) covering a 13 yr period between 1979 and 1992. We have analyzed the ultraviolet emission for the compact H II region and the NE and SW extended "jetlike" filamentary structures. The results of our ultraviolet analysis indicate that the H II region and features A, B, and D of the NE jet are increasing in intensity, while the SW counterjet, feature A', has declined in intensity. We have found much stronger evidence that the …
A Far-Ultraviolet Atlas Of Symbiotic Stars Observed With Iue. I. The Swp Range, S. R. Meier, Menas Kafatos, R. P. Fahey, A. G. Michalitsianos
A Far-Ultraviolet Atlas Of Symbiotic Stars Observed With Iue. I. The Swp Range, S. R. Meier, Menas Kafatos, R. P. Fahey, A. G. Michalitsianos
Mathematics, Physics, and Computer Science Faculty Articles and Research
This atlas contains sample spectra from the far-ultraviolet observations of32 symbiotic stars obtained with the lnternational Ultraviolet Explorer (IUE) satellite. In all, 394 low-resolution spectra from the short-wavelength pnmary (SWP) camera covering the range 1200-2000 A have been extracted from the IUE archive, calibrated, and measured. Absolute line fluxes and wavelengths for the prominent emission lines have been tabulated. Tables of both the general properties of these symbiotics and of features specific to the spectrum of each are included. The spectra shown are representative of the different classes of symbiotic stars that are currently in the IUE archive. These include …
Transonic Inviscid Disc Flows In The Schwarzschild Metric – I, Menas Kafatos, Ruixin Yang
Transonic Inviscid Disc Flows In The Schwarzschild Metric – I, Menas Kafatos, Ruixin Yang
Mathematics, Physics, and Computer Science Faculty Articles and Research
The coupled hydrodynamic equations governing equatorial flows applicable to inviscid disc accretion in the Schwarzschild metric are solved analytically and numerically. Here, we concentrate on the transonic solutions, that represent physically allowed accretion on to black holes. A polytropic equation linking gas pressure and density is assumed, and solutions are obtained for different conditions, such as isothermal and adiabatic gas flows. The dependence of those solutions on the angular momentum is explored. Under certain conditions, when there exist multiple possible sonic points, the numerical simulation automatically zeros in to the unique transonic solution passing through one of the sonic points.
Evidence Signalling The Start Of Enhanced Counterjet Flow In The Symbiotic System R Aquarii, A. G. Michalitsianos, M. Perez, Menas Kafatos
Evidence Signalling The Start Of Enhanced Counterjet Flow In The Symbiotic System R Aquarii, A. G. Michalitsianos, M. Perez, Menas Kafatos
Mathematics, Physics, and Computer Science Faculty Articles and Research
The velocity structure of strong far-UV emission lines observed in the symbiotic variable R Aqr suggests the start of new jet activity which will probably culminate in the appearance of a series of intense nebular emission knots within a decade. This is indicated by a systematic redward wavelength drift of emission lines, which we have followed with the International Ultraviolet Explorer (IV E) since the discovery of the brilliant northeast jet emission knots more than 10 years ago. The C IV λλ1548, 1550 resonance lines, which previously showed a prominent blue asymmetric wing that extended to velocities in excess -200 …
Relativistic Particle Transport In Hot Accretion Disks, P. A. Becker, Menas Kafatos, M. Maisack
Relativistic Particle Transport In Hot Accretion Disks, P. A. Becker, Menas Kafatos, M. Maisack
Mathematics, Physics, and Computer Science Faculty Articles and Research
Accretion disks around rapidly rotating black holes provide one of the few plausible models for the production of intense radiation in AGNs above energies of several hundred MeV. The rapid rotation of the hole increases the binding energy per nucleon in the last stable orbit relative to the Schwarzschild case, and naturally leads to ion temperatures in the range 10^12-10^13 K for sub-Eddington accretion rates. The protons in the hot inner region of a steady, two-temperature disk form a reservoir of energy that is sufficient to power the observed EGRET outbursts if the black hole mass is 10^10 M0 • …
Extended Variability Of The Symbiotic Star Ag Draconis, Menas Kafatos, S. R. Meier
Extended Variability Of The Symbiotic Star Ag Draconis, Menas Kafatos, S. R. Meier
Mathematics, Physics, and Computer Science Faculty Articles and Research
We have analyzed the complete set of available IUE (International Ultraviolet Explorer) spectra for the symbiotic star AG Draconis covering the period from 1979 to 1989. All absolute line fluxes and wavelengths have been obtained for the prominent emission lines in the λλ1200-3200 wavelength range. These spectra contain observations which were taken before, during and after the two extended outbursts which occurred on 1980 November to 1981 November and 1985 February to 1986 January. These two outburst events have two maxima that are separated by ~1600 days, a time scale not known to be associated with the star, but which …
Fe Ii Fluorescence And Anomalous C Iv Doublet Intensities In Symbiotic Novae, A. G. Michalitsianos, Menas Kafatos, S. R. Meier
Fe Ii Fluorescence And Anomalous C Iv Doublet Intensities In Symbiotic Novae, A. G. Michalitsianos, Menas Kafatos, S. R. Meier
Mathematics, Physics, and Computer Science Faculty Articles and Research
Symbiotic stars frequently exhibit anomalous C IV λλ1548.2, 1550.8 doublet flux ratios, in which the intensity ratio of the blue and red doublet members is below the optically thick limit of unity. Three symbiotic stars (RR Tel, RX Pup, and AG Peg) have been investigated in detail with high-resolution spectra obtained from the International Ultraviolet Explorer (IUE) archives. We have examined the deficit of C IV λ1548.2 emission relative to λ1550.8 in context with the fluorescent pumping of the Fe II multiplet (45.01) λ1548.204 by the C IV λ1548.2 line. In RR Tel the C IV λ1548.2 flux is correlated …
Ultraviolet And Optical Spectroscopy Of The R Aquarii Symmetrical Jet, J. M. Hollis, R. J. Oliverson, Menas Kafatos, A. G. Michalitsianos, R. M. Wagner
Ultraviolet And Optical Spectroscopy Of The R Aquarii Symmetrical Jet, J. M. Hollis, R. J. Oliverson, Menas Kafatos, A. G. Michalitsianos, R. M. Wagner
Mathematics, Physics, and Computer Science Faculty Articles and Research
The first ultraviolet spectrum of the southwest (SW) component of the symmetrical jet in the R Aquarii binary system has been obtained in the range 1200-2000 A with the International Ultraviolet Explorer (IUE). These results are compared to more encompassing spectra (1200-3200 A) of the central H II region taken at the same time and also similar spectra of the northeast (NE) jet component obtained 6 months earlier. Moreover, optical spectra of both the NE and SW jet components in the range 3400-9800 A were obtained within ~ 6 months and ~ 1 month, respectively, of the ultraviolet spectra. These …
Forbidden Lines Of Np^Q Ions. Ii. Line Intensities, J. P. Lynch, Menas Kafatos
Forbidden Lines Of Np^Q Ions. Ii. Line Intensities, J. P. Lynch, Menas Kafatos
Mathematics, Physics, and Computer Science Faculty Articles and Research
Ground state forbidden transitions of np^q ions of C, N, 0, Ne, Mg, Si, S, and Fe can provide important information on the state of cosmic ionized gases. Wavelengths of these lines are in the far- and near-UV visible and near- and far-IR regions of the spectrum. The line intensity ratios of particular transitions in q = 2, 4 ions can provide information on the temperature of the gas and in q = 3 ions information on the density of the gas. In the present work we have tabulated the line intensities of 95 transitions of these ions, which include …