Remote sensing in the mixing zone

Characteristics of dispersion and diffusion as the mechanisms by which pollutants are transported in natural river courses were studied with the view of providing additional data for the establishment of water quality guidelines and effluent outfall design protocols. Work has been divided into four basic categories which are directed at the basic goal of developing relationships which will permit the estimation of the nature and extent of the mixing zone as a function of those variables which characterize the outfall structure, the effluent, and the river, as well as climatological conditions. The four basic categories of effort are: (1) the development of mathematical models; (2) laboratory studies of physical models; (3) field surveys involving ground and aerial sensing; and (4) correlation between aerial photographic imagery and mixing zone characteristics

Spatially Resolved Spitzer-IRS Spectral Maps of the Superwind in M82

We have mapped the superwind/halo region of the nearby starburst galaxy M82 in the mid-infrared with $Spitzer-IRS$. The spectral regions covered include the H$_2 S(1)-S(3)$, [NeII], [NeIII] emission lines and PAH features. We estimate the total warm H$_2$ mass and the kinetic energy of the outflowing warm molecular gas to be between $M_{warm}\sim5-17\times10^6$ M$_{\odot}$ and $E_{K}\sim6-20\times10^{53}$ erg. Using the ratios of the 6.2, 7.7 and 11.3 micron PAH features in the IRS spectra, we are able to estimate the average size and ionization state of the small grains in the superwind. There are large variations in the PAH flux ratios throughout the outflow. The 11.3/7.7 and the 6.2/7.7 PAH ratios both vary by more than a factor of five across the wind region. The Northern part of the wind has a significant population of PAH's with smaller 6.2/7.7 ratios than either the starburst disk or the Southern wind, indicating that on average, PAH emitters are larger and more ionized. The warm molecular gas to PAH flux ratios (H$_2/PAH$) are enhanced in the outflow by factors of 10-100 as compared to the starburst disk. This enhancement in the H$_2/PAH$ ratio does not seem to follow the ionization of the atomic gas (as measured with the [NeIII]/[NeII] line flux ratio) in the outflow. This suggests that much of the warm H$_2$ in the outflow is excited by shocks. The observed H$_2$ line intensities can be reproduced with low velocity shocks ($v < 40$ km s$^{-1}$) driven into moderately dense molecular gas ($10^2 <n_H < 10^4$ cm$^{-3}$) entrained in the outflow.Comment: 19 pages and 12 figures; accepted in MNRA

Feedback in the local LBG Analog Haro 11 as probed by far-UV and X-ray observations

We have re-analyzed FUSE data and obtained new Chandra observations of Haro 11, a local (D_L=88 Mpc) UV luminous galaxy. Haro 11 has a similar far-UV luminosity (10^10.3 L_\odot), UV surface brightness (10^9.4 L_\odot kpc^-2), SFR, and metallicity to that observed in Lyman Break Galaxies (LBGs). We show that Haro 11 has extended, soft thermal (kT~0.68 keV) X-ray emission with a luminosity and size which scales with the physical properties (e.g. SFR, stellar mass) of the host galaxy. An enhanced alpha/Fe, ratio of ~4 relative to solar abundance suggests significant supernovae enrichment. These results are consistent with the X-ray emission being produced in a shock between a supernovae driven outflow and the ambient material. The FUV spectra show strong absorption lines similar to those observed in LBG spectra. A blueshifted absorption component is identified as a wind outflowing at ~200-280 km/s. OVI\lambda\lambda1032,1038 emission, the dominant cooling mechanism for coronal gas at T~10^5.5 K is also observed. If associated with the outflow, the luminosity of the OVI emission suggests that <20% of the total mechanical energy from the supernovae and solar winds is being radiated away. This implies that radiative cooling through OVI is not significantly inhibiting the growth of the outflowing gas. In contradiction to the findings of Bergvall et al 2006, we find no convincing evidence of Lyman continuum leakage in Haro 11. We conclude that the wind has not created a `tunnel' allowing the escape of a significant fraction of Lyman continuum photons and place a limit on the escape fraction of f_{esc}<2%. Overall, both Haro 11 and a previously observed LBG analogue VV 114, provide an invaluable insight into the X-ray and FUV properties of high redshift LBGs.Comment: Accepted for publication in ApJ, 40 pages, 17 figure

A Far-Ultraviolet View of Starburst Galaxies

Recent observational and theoretical results on starburst galaxies related to the wavelength regime below 1200 A are discussed. The review covers stars, dust, as well as hot and cold gas. This wavelength region follows trends similar to those seen at longer wavelengths, with several notable exceptions. Even the youngest stellar populations show a turn-over in their spectral energy distributions, and line-blanketing is much more pronounced. Furthermore, the O VI line allows one to probe gas at higher temperatures than possible with lines at longer wavelengths. Molecular hydrogen lines (if detected) provide a glimpse of the cold phase. I cover the crucial wavelength regime below 912 A and the implications of recent attempts to detect the escaping ionizing radiation.Comment: 8 pages, 3 figures, Invited Talk, Starbursts--From 30 Doradus to Lyman-Break Galaxies, ed. R. de Grijs & R. M. Gonzalez Delgado (Dordrecht: Kluwer

The Contribution of Field OB Stars to the Ionization of the Diffuse Ionized Gas in M33

(Abridged) We present a study of the ionizing stars associated with the diffuse ionized gas (DIG) and HII regions in the nearby spiral galaxy M33. We compare our Schmidt H-alpha image to the far-ultraviolet (FUV, 1520A) image from the Ultraviolet Imaging Telescope (UIT). The H-alpha/FUV ratio is higher in HII regions than in the DIG, suggesting an older population of ionizing stars in the DIG. When compared to models of evolving stellar populations, the N(Lyc)/FUV ratio in HII regions is consistent with a young burst, while the DIG ratio resembles an older burst population, or a steady state population built up by constant star formation. The UIT data is complimented with archival FUV and optical images of a small portion of the disk of M33 obtained with WFPC2 on HST. Using the HST FUV and optical photometry, we assign spectral types to the stars observed in DIG and HII regions. The photometry indicates that ionizing stars are present in the DIG. We compare the predicted ionizing flux with the amount required to produce the observed H-alpha emission, and find that field OB stars in the HST images can account for 40% +/- 12% of the ionization of the DIG, while the stars in HII regions can provide 107% +/- 26% of the H-alpha luminosity of the HII regions. We do not find any correlation between leakage of ionizing photons and H-alpha luminosity for the HII regions in these HST fields. If stellar photons alone are responsible for ionizing the DIG, the current results are consistent with no or few ionizing photons escaping from the galaxy.Comment: 30 pages, 7 figures, accepted for publication in Ap

Parental bonding and identity style as correlates of self-esteem among adult adoptees and nonadoptees

Adult adoptees (n equals 100) and non-adoptees (n equals 100) were compared with regard to selfesteem, identity processing style, and parental bonding. While some differences were found with regard to self-esteem, maternal care, and maternal overprotection, these differences were qualified by reunion status such that only reunited adoptees differed significantly from nonadoptees. Moreover, hierarchical regression analyses indicated that parental bonding and identity processing style were more important than adoptive status per se in predicting self esteem. Implications for practitioners who work with adoptees are discussed

Far-Ultraviolet & X-ray Observations of VV 114: Feedback in a Local Analog to Lyman Break Galaxies

We have analyzed FUSE, XMM, and Chandra observations of VV 114, a local galaxy merger with strong similarities to typical high-redshift Lyman Break Galaxies (LBGs). Diffuse thermal X-ray emission encompassing VV114 has been observed by Chandra and XMM. This region of hot (kT~0.59 keV) gas has an enhanced alpha to iron element ratio relative to solar abundances and follows the same relation as typical starbursts between its properties (luminosity, size, and temperature) and those of the starburst galaxy (star formation rate, dust temperature, galaxy mass). These results are consistent with the X-ray gas having been produced by shocks driven by a galactic superwind. The FUSE observations of VV 114 show strong, broad interstellar absorption lines with a pronounced blueshifted component(similar to what is seen in LBGs). This implies an outflow of material moving at 300-400 km/s relative to VV 114. The properties of the strong OVI absorption line are consistent with radiative cooling at the interface between the hot outrushing gas seen in X-rays and the cooler material seen in the other outflowing ions in the FUSE data. We show that the wind in VV114 has not created a ``tunnel'' that enables more than a small fraction (< few percent) of the ionizing photons from VV114 to escape into the IGM. Taken together, these data provide a more complete physical basis for understanding the outflows that seem to be generic in LBGs. This will lead to improved insight into the role that such outflows play in the evolution of galaxies and the inter-galactic medium.Comment: 33 pages, 13 figure