Winds from Nuclear Starbursts: Old Truths and Recent Progress on Superwinds

I will discuss a few select aspects of the most common and best understood galactic-scale outflow -- starburst-driven superwinds, focusing on winds from nuclear starburst galaxies. I will show that modern observations, in particular in the soft and hard X-ray bands, complement and reinforce the existing paradigm of superwinds as flows collectively driven by multiple SNe. The properties of the diffuse X-ray emission from dwarf starburst galaxies, L_BOL ~ L_* starbursts in spiral galaxies, and ULIRGS, are all consistent with superwind activity. Where appropriate, I contrast the physics of starburst-driven winds with poorly collimated winds from AGN, and discuss what we know of the role of LLAGN and Seyfert nuclei in starburst superwind galaxies.Comment: To appear in the proceedings of IAU symposium 222: The Interplay among Black Holes, Stars and ISM in Galactic Nuclei, held in Gramado, Brazil, March 1-5 2004. Eds. Th. Storchi Bergmann, L.C. Ho & H.R. Schmitt. 6 pages, 1 figur

Predicting X-ray emission from wind-blown bubbles - Limitations of fits to ROSAT spectra

Wind-blown bubbles, from those around massive O and Wolf-Rayet stars, to superbubbles around OB associations and galactic winds in starburst galaxies, have a dominant role in determining the structure of the Interstellar Medium. X-ray observations of these bubbles are particularly important as most of their volume is taken up with hot gas, 1E5 < T (K) < 1E8. However, it is difficult to compare X-ray observations, usually analysed in terms of single or two temperature spectral model fits, with theoretical models, as real bubbles do not have such simple temperature distributions. In this introduction to a series of papers detailing the observable X-ray properties of wind-blown bubbles, we describe our method with which we aim to solve this problem, analysing a simulation of a wind-blown bubble around a massive star. We model a wind of constant mass and energy injection rate, blowing into a uniform ISM, from which we calculate X-ray spectra as would be seen by the ROSAT PSPC. We compare the properties of the bubble as would be inferred from the ROSAT data with the true properties of the bubble in the simulation. We find standard spectral models yield inferred properties that deviate significantly from the true properties, even though the spectral fits are statistically acceptable, and give no indication that they do not represent to true spectral distribution. Our results suggest that in any case where the true source spectrum does not come from a simple single or two temperature distribution the "observed" X-ray properties cannot naively be used to infer the true properties.Comment: 14 pages, LaTeX with 13 eps figures, condensed abstract. MNRAS in pres

The Impact of Starbursts on the Circumgalactic Medium

We present a study exploring the impact of a starburst on the properties of the surrounding circum-galactic medium (CGM): gas located beyond the galaxy's stellar body and extending out to the virial radius (200 kpc). We obtained ultraviolet spectroscopic data from the Cosmic Origin Spectrograph (COS) probing the CGM of 20 low-redshift foreground galaxies using background QSOs. Our sample consists of starburst and control galaxies. The latter comprises normal star-forming and passive galaxies with similar stellar masses and impact parameters as the starbursts. We used optical spectra from the Sloan Digital Sky Survey(SDSS) to estimate the properties of the starbursts, inferring average ages of 200 Myrs and burst fractions involving ~10% of their stellar mass. The COS data reveal highly ionized gas traced by CIV in 80%(4/5) of the starburst and in 17%(2/12) of the control sample. The two control galaxies with CIV absorbers differed from the four starbursts in showing multiple low-ionization transitions and strong saturated Lyman-alpha lines. They therefore appear to be physically different systems. We show that the CIV absorbers in the starburst CGM represent a significant baryon repository. The high detection rate of this highly ionized material in the starbursts suggests that starburst-driven winds can affect the CGM out to radii as large as 200 kpc. This is plausible given the inferred properties of the starbursts and the known properties of starburst-driven winds. This would represent the first direct observational evidence of local starbursts impacting the bulk of their gaseous halos, and as such provides new evidence of the importance of this kind of feedback in the evolution of galaxies.Comment: Accepted for publication in Ap

Union with Christ in the theology of Samuel Rutherford: an examination of his doctrine of the Holy Spirit

By way of introducing this doctrinal study, we have traced in broad outline the effects of Hellenistic philosophy on the theology of the Holy Spirit. After reviewing some of the errors which arose in the identification of the Spirit with the creation of mediating grace, we noted that there was also a tradition which avoided the worst aspects of Greek dualism by identifying the Third Person of the Trinity with grace as a continuing realisation of the mission of Christ in history. The pneumatological theology of Samuel Rutherford manifests this emphasis in 17th Cent. Scotland. his doctrine of the Spirit is consciously integrated with his understanding of the Trinity in general and with Christology in particular. The Son and the Spirit are both sent according to the plan of the Father. The Spirit in his soteriological office is subject to the Son and produces by recreation the life of the Son in those chosen by the Father. Thus regeneration, faith, repentance, and sanctification are the believer's by an actual union of participation in the life of Christ. This activity of the Spirit presupposes not only His use of the Scriptures which He has caused to be written as an unerring revelation of God's will, but also His absolute control of all creation. The Spirit's power in this regard is manifest in every part of the world but most obviously in the Church which He guides and vitalises and in the life of the individual believer who is constantly under His influences. The presence of the Holy Spirit in man does not create a bridge between him and Christ as by a creaturely means nor does it annihilate the believer's personhood or responsibility as by an absolute imputation of Christ's life. Rather, by drawing men into a living union with the living Christ, the Holy Spirit establishes man's true creatureliness and his responsibility in an act of worshipping the triune God in and through Jesus Christ

My Sociology: The Challenge of Transforming Classroom Culture from a Focus on Grades to a Focus on Learning

This paper documents the pedagogical remodeling of an Introduction to Sociology course. The challenge is to transform the classroom culture, and ultimately the college culture, from a focus on grades to a focus on learning. This transformation is accomplished through a series of learning activities embodied in My Sociology resources, which have been designed to be not merely learner-centered but ego-centered. Seasoned professors have often commented that students seem to perk up when the lesson is about them. Taking advantage of this energy, the discussion of sociology in this course begins with a treatment of the self, and then branches out systematically to the global perspective. Preliminary experimental model research comparing this pedagogically remodeled teaching strategy to the traditional teaching model has shown the remodeled strategy to be statistically significantly more effective (p \u3c .001) than the traditional model of teaching. This course remodeling can be done with any academic course and can be applied to many specialty areas

The Energetics and Mass-loss of Mrk33

We present ROSAT HRI X-ray data and optical imaging of the important dwarf starburst Markarian 33. We find an extended, complex, shell-like morphology in the X-ray emission, with an extent of 2.3 x 1.9kpc, coincident with the bright star-forming regions at the centre of the galaxy. The physical extent of this X-ray emission from Mrk 33 is very similar to the observed Halpha emission, and suggests that the bulk of the X-ray emission is coming from an expanding superbubble. We estimate the age and mass of Mrk 33's starburst to be 5.8 Myr and 6.9 x 10^{6} Msolar respectively with the energy injection rate in the central regions of the galaxy being 10^{41} erg/s, while the associated mass-loss rate from the star-forming regions is estimated to be 0.2 Msolar/yr. We suggest that the X-ray emission is predominantly powered by starburst type activity and argue that a blowout in the form of a galactic wind is the most likely fate for Mrk 33 resulting in the loss of most of the galaxy's metal-enriched material and a small fraction (<1 per cent) of the ISM.Comment: 13 pages, 6 figures, accepted for publication in MNRA

Current Assessment and Future Prediction of Forest Cover Change in Cumberland and Morgan Counties, Tennessee: A Modeling Technique

Determining the relationship between human disturbance of the environment and natural forest change is critical for sound natural resource planning. Improved land cover modeling techniques that incorporate geographic information systems and statistical models are needed to assist in this analysis. Continued forest fragmentation due to increasing population and urbanization has created a growing interest in forest protection for the Cumberland Plateau of Tennessee. Specifically, Cumberland and Morgan Counties have seen unprecedented population growth over the last two decades, resulting in fragmentation of forestland. This study developed a model to determine the probability of exurbia development and its resulting forest fragmentation. Geographic data used in the research included satellite imagery from 1992 and 2000, U.S. Census population and demographic estimates, and road and water coverages for the two counties. The first objective of this study was to develop an accurate and efficient procedure for the development of a land cover map for use in a forest change detection system for Cumberland and Morgan Counties, Tennessee. A unique method was developed to generate this procedure by combining post-classification and image differencing. The second objective of the study was to determine the relationship between urbanization and forest loss in Cumberland and Morgan Counties, Tennessee, and to predict current and future land cover patterns. Logistic regression analysis suggested that demographic variables such as education and population along with spatial factors such as slope, distance to water, distance to interstate junctions, and gravity index factors of nearby urban retail centers, significantly influenced the transition of forest to urban cover. Of these parameters, a high gravity index, a suburban designation, and unsloped terrain had the greatest impact on forest to urban conversion. In addition, spatial factors such as parcel distance to water, and parcel distance to interstate junctions significantly influenced the probability of development. Finally, using population density predictions, the model identified the probability that forest land would be urbanized by 2010