A survey on the motivation of instrumental study in the schools of Massachusetts.

Thesis (M.M.E.)--Boston UniversityIn planning instrumental programs, the supervisor wishes to incorporate those factors of encouragement and stimulus which will most effectively contribute to the growth of the the instrumental work. The problem of this study is to find out by mean of an adequate survey, what these successful factors have been in the experience of other school systems which have used them. [TRUNCATED

The Diverse Infrared Properties of a Complete Sample of Star-Forming Dwarf Galaxies

We present mid-infrared Spitzer Space Telescope observations of a complete sample of star-forming dwarf galaxies selected from the KPNO International Spectroscopic Survey. The galaxies span a wide range in mid-infrared properties. Contrary to expectations, some of the galaxies emit strongly at 8 micron indicating the presence of hot dust and/or PAHs. The ratio of this mid-infrared dust emission to the stellar emission is compared with the galaxies' luminosity, star-formation rate, metallicity, and optical reddening. We find that the strength of the 8.0 micron dust emission to the stellar emission ratio is more strongly correlated with the star-formation rate than it is with the metallicity or the optical reddening in these systems. Nonetheless, there is a correlation between the 8.0 micron luminosity and metallicity. The slope of this luminosity-metallicity correlation is shallower than corresponding ones in the B-band and 3.6 micron. The precise nature of the 8.0 micron emission seen in these galaxies (i.e., PAH versus hot dust or some combination of the two) will require future study, including deep mid-IR spectroscopy.Comment: 14 pages, accepted Ap

Emerging Disparities among Self-Pay Trauma Patients

Preliminary results from a study of trauma patients in Southern Nevada are yielding some unexpected findings with implications for both trauma centers and the growing Hispanic population. Hispanic patients are more likely to be self pay irrespective of income level and employment status when compared to non-Hispanic patient groups. Further, self pay Hispanics, unlike their non-Hispanic, self pay counterparts, tend to be employed, have families, and report stable living conditions. The implication is that the financial and social cost of traumatic injury may place a significant burden on trauma centers, patients, their families and the community

The KPNO International Spectroscopic Survey. V. H-alpha-selected Survey List 3

The KPNO International Spectroscopic Survey (KISS) is an objective-prism survey designed to detect extragalactic emission-line objects. It combines many of the features of previous slitless spectroscopic surveys with the advantages of modern CCD detectors, and is the first purely digital objective-prism survey for emission-line galaxies (ELGs). Here we present the third list of ELG candidates selected from our red spectral data, which cover the wavelength range 6400 to 7200 A. In most cases, the detected emission line is H-alpha. The current survey list covers the region of the NOAO Deep Wide-Field Survey (NDWFS). This survey covers two fields; the first is 3 x 3 degrees square and located at RA = 14h 30m, DEC = 34.5 deg (B1950), the second is 2.3 x 4.0 degrees and centered at RA = 2h 7.5m, DEC = -4.75 deg. A total area of 19.65 deg^2 is covered by the KISS data. A total of 261 candidate emission-line objects have been selected for inclusion in the survey list (13.3 per deg^2). We tabulate accurate coordinates and photometry for each source, as well as estimates of the redshift, emission-line flux and line equivalent width based on measurements of the digital objective-prism spectra. The properties of the KISS ELGs are examined using the available observational data. When combined with the wealth of multi-wavelength data already available for the NDWFS fields, the current list of KISS ELGs should provide a valuable tool for studying star-formation and nuclear activity in galaxies in the local universe.Comment: 18 pages, including 10 figures and 4 tables. Accepted for publication in the December, 2005 A

Radio Continuum Emission at 1.4 GHz from KISS Emission-Line Galaxies

We have searched the Faint Images of the Radio Sky at Twenty centimeters (FIRST) and the NRAO VLA Sky Survey (NVSS) 1.4 GHz radio surveys for sources that are coincident with emission-line galaxy (ELG) candidates from the KPNO International Spectroscopic Survey (KISS). A total of 207 of the 2157 KISS ELGs (~10%) in the first two H-alpha-selected survey lists were found to possess radio detections in FIRST and/or NVSS. Follow-up spectra exist for all of the radio detections, allowing us to determine the activity type (star-forming vs. AGN) for the entire sample. We explore the properties of the radio-detected KISS galaxies in order to gain a better insight into the nature of radio-emitting galaxies in the local universe (z < 0.1). No dwarf galaxies were detected, despite the large numbers of low-luminosity galaxies present in KISS, suggesting that lower mass, lower luminosity objects do not possess strong galaxian-scale magnetic fields. Due to the selection technique used for KISS, our radio ELGs represent a quasi-volume-limited sample, which allows us to develop a clearer picture of the radio galaxy population at low redshift. Nearly 2/3rds of the KISS radio galaxies are starburst/star-forming galaxies, which is in stark contrast to the results of flux-limited radio surveys that are dominated by AGNs and elliptical galaxies (i.e., classic radio galaxies). While there are many AGNs among the KISS radio galaxies, there are no objects with large radio powers in our local volume. We derive a radio luminosity function (RLF) for the KISS ELGs that agrees very well with previous RLFs that adequately sample the lower-luminosity radio population.Comment: Accepted for publication in the Astronomical Journal (April 2004); 23 pages, 16 figure

The KPNO International Spectroscopic Survey. IV. H-alpha-selected Survey List 2

The KPNO International Spectroscopic Survey (KISS) is an objective-prism survey for extragalactic emission-line objects. It combines many of the features of previous slitless spectroscopic surveys with the advantages of modern CCD detectors, and is the first purely digital objective-prism survey for emission-line galaxies. Here we present the second list of emission-line galaxy candidates selected from our red spectral data, which cover the wavelength range 6400 to 7200 A. In most cases, the detected emission line is H-alpha. The current survey list covers a 1.6-degree-wide strip located at Dec(1950) = 43d 30' and spans the RA range 11h 55m to 16h 15m. The survey strip runs through the center of the Bootes Void, and has enough depth to adequately sample the far side of the void. An area of 65.8 sq. deg. is covered. A total of 1029 candidate emission-line objects have been selected for inclusion in the survey list (15.6 per sq. deg.). We tabulate accurate coordinates and photometry for each source, as well as estimates of the redshift and emission-line flux and equivalent width based on measurements of the digital objective-prism spectra. The properties of the KISS emission-line galaxies are examined using the available observational data. Although the current survey covers only a modest fraction of the total volume of the Bootes Void, we catalog at least twelve objects that appear to be located within the void. Only one of these objects has been recognized previously as a void galaxy.Comment: Accepted for publication in the Astronomical Journal (April 2004); 20 pages, 12 figure

KISS AGNs in the Soft X-ray Band: Correlation with the ROSAT All-Sky Survey

We present a study of the X-ray properties of a volume-limited sample of optically selected emission-line galaxies. The sample is derived from a correlation between the KPNO International Spectroscopic Survey (KISS), an H-alpha-selected objective-prism survey of AGNs and starbursting galaxies, and the ROSAT All-Sky Survey (RASS). After elimination of all spurious matches, we identify 18 ROSAT-detected X-ray sources within the KISS sample in the 0.1-2.4 keV band. Due to soft X-ray selection effects, the majority of the ROSAT sources are Seyfert 1 galaxies. The majority (54%) of the ROSAT-KISS Seyferts are classified as narrow-line Seyfert 1 objects, a relatively high percentage compared to previous objective-prism-selected Seyfert galaxy samples. We estimate the X-ray luminosities of the ROSAT-detected KISS objects and derive volume emissivities of 6.63 x 10^38 ergs/s/Mpc^3 and 1.45 x 10^38 ergs/s/Mpc^3 for the 30 deg and 43 deg survey strips, respectively. For those KISS AGNs not detected by RASS, we use the median L_X/L_H-alpha ratio derived from a previous study to estimate L_X. The total 0.5-2 keV volume emissivity we predict for the overall KISS AGN sample is sufficient to account for 22.1 +/- 8.9% of the soft X-ray background (XRB), averaged over both survey strips. The KISS AGN sample is made up predominantly of intermediate-luminosity Seyfert 2's and LINERs, which tend to be weak soft X-ray sources. They may, however, represent a much more significant contribution to the hard XRB.Comment: 15 pages, including 5 figures and 2 tables. Accepted for publication in December 2002 A

Optical Star-Formation Rate Indicators

Using integrated optical spectrophotometry for 412 star-forming galaxies at z~0, and fiber-aperture spectrophotometry for 120,846 SDSS galaxies at z~0.1, we investigate the H-alpha, H-beta, [O II] 3727, and [O III] 5007 nebular emission lines and the U-band luminosity as quantitative star-formation rate (SFR) indicators. We demonstrate that the extinction-corrected H-alpha luminosity is a reliable SFR tracer even in highly obscured star-forming galaxies. We find that variations in dust reddening dominate the systematic uncertainty in SFRs derived from the observed H-beta, [O II], and U-band luminosities, producing a factor of ~1.7, ~2.5, and ~2.1 scatter in the mean transformations, respectively. We show that [O II] depends weakly on variations in oxygen abundance over a wide range in metallicity, 12+log(O/H)=8.15-8.7 dex (Z/Z_sun=0.28-1.0), and that in this metallicity interval galaxies occupy a narrow range in ionization parameter (-3.8<log U<-2.9 dex). We show that the scatter in [O III] 5007 as a SFR indicator is a factor of 3-4 due to its sensitivity to metal abundance and ionization. We develop empirical SFR calibrations for H-beta and [O II] parameterized in terms of the B-band luminosity, which remove the systematic effects of reddening and metallicity, and reduce the SFR scatter to +/-40% and +/-90%, respectively, although individual galaxies may deviate substantially from the median relations. Finally, we compare the z~0 relations between blue luminosity and reddening, ionization, and [O II]/H-alpha ratio against measurements at z~1 and find broad agreement. (Abridged.)Comment: ApJ, accepted; no changes from previously posted version; emulateapj style; 41 pages, 23 figures, 2 table

Structures of Local Galaxies Compared to High Redshift Star-forming Galaxies

The rest-frame far-ultraviolet (FUV) morphologies of 8 nearby interacting and starburst galaxies (Arp 269, M 82, Mrk 8, NGC 520, NGC 1068, NGC 3079, NGC 3310, NGC 7673) are compared with 54 galaxies at z ~ 1.5 and 46 galaxies at z ~ 4 observed in the GOODS-ACS field. The nearby sample is artificially redshifted to z ~ 1.5 and 4. We compare the simulated galaxy morphologies to real z ~ 1.5 and 4 UV-bright galaxy morphologies. We calculate the Gini coefficient (G), the second-order moment of the brightest 20% of the galaxy's flux (M_20), and the Sersic index (n). We explore the use of nonparametric methods with 2D profile fitting and find the combination of M_20 with n an efficient method to classify galaxies as having merger, exponential disk, or bulge-like morphologies. When classified according to G and M_20, 20/30% of real/simulated galaxies at z ~ 1.5 and 37/12% at z ~ 4 have bulge-like morphologies. The rest have merger-like or intermediate distributions. Alternatively, when classified according to the Sersic index, 70% of the z ~ 1.5 and z ~ 4 real galaxies are exponential disks or bulge-like with n > 0.8, and ~30% of the real galaxies are classified as mergers. The artificially redshifted galaxies have n values with ~35% bulge or exponential at z ~ 1.5 and 4. Therefore, ~20-30% of Lyman-break galaxies (LBGs) have structures similar to local starburst mergers, and may be driven by similar processes. We assume merger-like or clumpy star-forming galaxies in the GOODS field have morphological structure with values n -1.7. We conclude that Mrk 8, NGC 3079, and NGC 7673 have structures similar to those of merger-like and clumpy star-forming galaxies observed at z ~ 1.5 and 4.Comment: Accepted by The Astronomical Journal May 2009. Changes include an added explanation of methods in Section

Superhumps in Cataclysmic Binaries. XXIV. Twenty More Dwarf Novae

We report precise measures of the orbital and superhump period in twenty more dwarf novae. For ten stars, we report new and confirmed spectroscopic periods - signifying the orbital period P_o - as well as the superhump period P_sh. These are GX Cas, HO Del, HS Vir, BC UMa, RZ Leo, KV Dra, KS UMa, TU Crt, QW Ser, and RZ Sge. For the remaining ten, we report a medley of P_o and P_sh measurements from photometry; most are new, with some confirmations of previous values. These are KV And, LL And, WX Cet, MM Hya, AO Oct, V2051 Oph, NY Ser, KK Tel, HV Vir, and RX J1155.4-5641. Periods, as usual, can be measured to high accuracy, and these are of special interest since they carry dynamical information about the binary. We still have not quite learned how to read the music, but a few things are clear. The fractional superhump excess epsilon [=(P_sh-P_o)/P_o] varies smoothly with P_o. The scatter of the points about that smooth curve is quite low, and can be used to limit the intrinsic scatter in M_1, the white dwarf mass, and the mass-radius relation of the secondary. The dispersion in M_1 does not exceed 24%, and the secondary-star radii scatter by no more than 11% from a fixed mass-radius relation. For the well-behaved part of epsilon(P_o) space, we estimate from superhump theory that the secondaries are 18+-6% larger than theoretical ZAMS stars. This affects some other testable predictions about the secondaries: at a fixed P_o, it suggests that the secondaries are (compared with ZAMS predictions) 40+-14% less massive, 12+-4% smaller, 19+-6% cooler, and less luminous by a factor 2.5(7). The presence of a well-defined mass-radius relation, reflected in a well-defined epsilon(P_o) relation, strongly limits effects of nuclear evolution in the secondaries.Comment: PDF, 62 pages, 7 tables, 21 figures; accepted, in press, to appear November 2003, PASP; more info at http://cba.phys.columbia.edu