Environments of Redshift Survey Compact Groups of Galaxies

Redshift Survey Compact Groups (RSCGs) are tight knots of N >= 3 galaxies selected from the CfA2+SSRS2 redshift survey. The selection is based on physical extent and association in redshift space alone. We measured 300 new redshifts of fainter galaxies within 1 h^{-1} Mpc of 14 RSCGs to explore the relationship between RSCGs and their environments. 13 of 14 RSCGs are embedded in overdense regions of redshift space. The systems range from a loose group of 5 members to an Abell cluster. The remaining group, RSCG 64, appears isolated. RSCGs are isolated and distinct from their surroundings to varying degrees, as are the Hickson Compact Groups. Among the 13 embedded RSCGs, 3 are distinct from their general environments (RSCG 9, RSCG 11 and RSCG 85).Comment: 35 pages, including 10 figures and 5 tables, accepted for publication in the Astronomical Journa

Tidally Triggered Star Formation in Close Pairs of Galaxies: Major and Minor Interactions

We study star formation in a sample of 345 galaxies in 167 pairs and compact groups drawn from the original CfA2 Redshift Survey and from a follow-up search for companions. We construct our sample with attention to including pairs with luminosity contrast |\Delta m_R| >= 2. These 57 galaxies with |\Delta m_R| >= 2 provide a set of nearby representative cases of minor interactions, a central feature of the hierarchical galaxy formation model. Here we report the redshifts and positions of the 345 galaxies in our sample, and of 136 galaxies in apparent pairs that are superpositions. In the pairs sample as a whole, there are strong correlations between the equivalent width of the H\alpha emission line and the projected spatial and the line-of-sight velocity separation of the pair. For pairs of small luminosity contrast, |\Delta m_R| < 2, the member galaxies show a correlation between the equivalent width of H\alpha and the projected spatial separation of the pair. However, for pairs with large luminosity contrast, |\Delta m_R| >= 2, we detect no correlation between the equivalent width of H\alpha and the projected spatial separation. The relative luminosity of the companion galaxy is more important in a gravitational tidal interaction than the intrinsic luminosity of the galaxy. Central star formation across the entire pairs sample depends strongly on the luminosity ratio, |\Delta m_R|, a reasonable proxy for the mass ratio of the pair; pairs composed of similarly luminous galaxies produce the strongest bursts of star formation. Pairs with |\Delta m_R| >= 2 rarely have EW(H\alpha) >~ 70 Ang.Comment: Minor revisions following journal proof

Kinematic Effects of Tidal Interaction on Galaxy Rotation Curves

We use self-consistent N-body models, in conjunction with models of test particles moving in galaxy potentials, to explore the initial effects of interactions on the rotation curves of spiral galaxies. Using nearly self-consistent disk/bulge/halo galaxy models (Kuijken & Dubinski 1995), we simulate the first pass of galaxies on nearly parabolic orbits; we vary orbit inclinations, galaxy halo masses and impact parameters. For each simulation, we mimic observed rotation curves of the model galaxies. Transient interaction-induced features of the curves include distinctly rising or falling profiles at large radii and pronounced bumps in the central regions. Remarkably similar features occur in our statistical sample of optical emission-line rotation curves of spiral galaxies in tight pairs and n-tuples.Comment: 9 pages, 2 figures, accepted for publication in ApJ Letter

Incidence and Risk Factors for Pelvic Pain After Mesh Implant Surgery for the Treatment of Pelvic Floor Disorders

Our aim was to assess incidence and risk factors for pelvic pain after pelvic mesh implantation

Tidally-Triggered Star Formation in Close Pairs of Galaxies

We analyze new optical spectra of a sample of 502 galaxies in close pairs and n-tuples, separated by <= 50/h kpc. We extracted the sample objectively from the CfA2 redshift survey, without regard to the surroundings of the tight systems. We probe the relationship between star formation and the dynamics of the systems of galaxies. The equivalent widths of H\alpha (EW(H\alpha) and other emission lines anti-correlate strongly with pair spatial separation (\Delta D) and velocity separation. We use the measured EW(H\alpha) and the starburst models of Leitherer et al. to estimate the time since the most recent burst of star for- mation began for each galaxy. In the absence of a large contribution from an old stellar population to the continuum around H\alpha, the observed \Delta D -- EW(H\alpha) correlation signifies that starbursts with larger separations on the sky are, on average, older. By matching the dynamical timescale to the burst timescale, we show that the data support a simple picture in which a close pass initiates a starburst; EW(H\alpha) decreases with time as the pair separation increases, accounting for the anti-correlation. This picture leads to a method for measuring the duration and the initial mass function of interaction-induced starbursts: our data are compatible with the starburst and orbit models in many respects, as long as the starburst lasts longer than \sim10^8 years and the delay between the close pass and the initiation of the starburst is less than a few \times 10^7 years. If there is no large contribution from an old stellar population to the continuum around H\alpha the Miller-Scalo and cutoff (M <= 30 M_\sun) Salpeter initial mass functions fit the data much better than a standard Salpeter IMF. (Abridged.)Comment: 43 pages, 22 figures, to appear in the ApJ; we correct an error which had minor effects on numerical values in the pape

Compact Group Selection From Redshift Surveys

For the first time, we construct a catalog of compact groups selected from a complete, magnitude-limited redshift survey. We select groups with $N \geq 3$ members based on projected separation and association in redshift space alone. We evaluate the characteristics of the Redshift Survey Compact Groups (RSCG's). Their physical properties (membership frequency, velocity dispersion, density) are similar to those of the Hickson [ApJ, 255, 382 (1982)] Compact Groups. Hickson's isolation criterion is a strong function of the physical and angular group radii and is a poor predictor of the group environment. In fact, most RSCG's are embedded in dense environments. The luminosity function for RSCG's is mildly inconsistent with the survey luminosity function --- the characteristic luminosity is brighter and the faint end shallower for the RSCG galaxies. We construct a model of the selection function of compact groups. Using this selection function, we estimate the abundance of RSCG's; for groups with $N \geq 4$ members the abundance is $3.8 \times 10^{-5} h^3 Mpc^{-3}$. For all RSCG's ($N \geq 3$) the abundance is $1.4 \times 10^{-4} h^3 Mpc^{-3}$.Comment: 41 pages, LaTeX, including 20 figures and 9 tables. Accepted for publication in The Astronomical Journal. Figures 3 and 4 available at ftp://cfa0.harvard.edu/outgoing/barto

Characterization of adolescent and pediatric renal cell carcinoma: A report from the Children's Oncology Group study AREN03B2

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/111918/1/cncr29368.pd

Rotation Curve Measurement using Cross-Correlation

Longslit spectroscopy is entering an era of increased spatial and spectral resolution and increased sample size. Improved instruments reveal complex velocity structure that cannot be described with a one-dimensional rotation curve, yet samples are too numerous to examine each galaxy in detail. Therefore, one goal of rotation curve measurement techniques is to flag cases in which the kinematic structure of the galaxy is more complex than a single-valued curve. We examine cross-correlation as a technique that is easily automated and works for low signal-to-noise spectra. We show that the technique yields well-defined errors which increase when the simple spectral model (template) is a poor match to the data, flagging those cases for later inspection. We compare the technique to the more traditional, parametric technique of simultaneous emission line fitting. When the line profile at a single slit position is non-Gaussian, the techniques disagree. For our model spectra with two well-separated velocity components, assigned velocities from the two techniques differ by up to ~52% of the velocity separation of the model components. However, careful use of the error statistics for either technique allows one to flag these non-Gaussian spectra.Comment: LaTeX document with 26 pages, including 12 figures; published in PAS

Prevalence of pelvic floor disorders in women with suspected gynecological malignancy: a survey-based study

Understanding of pelvic floor disorders among women with gynecological cancer is limited. The objective of this study was to describe the prevalence of pelvic floor disorders in women with suspected gynecological malignancy before surgery

The Tully-Fisher Relation as a Measure of Luminosity Evolution: A Low Redshift Baseline for Evolving Galaxies

We use optical rotation curves to investigate the R-band Tully-Fisher properties of a sample of 90 spiral galaxies in close pairs. The galaxies follow the Tully-Fisher relation remarkably well, with the exception of eight distinct 3-sigma outliers. Although most of the outliers show signs of recent star formation, gasdynamical effects are probably the dominant cause of their anomalous Tully-Fisher properties. Four outliers with small emission line widths have very centrally concentrated line emission and truncated rotation curves; the central emission indicates recent gas infall after a close galaxy-galaxy pass. These four galaxies may be local counterparts to compact, blue galaxies at intermediate redshift. The remaining galaxies have a negligible offset from the reference Tully-Fisher relation, but a shallower slope (2.6-sigma significance) and a 25% larger scatter. We characterize the non-outlier sample with measures of distortion and star formation to search for third parameter dependence in the residuals of the TF relation. Severe kinematic distortion is the only significant predictor of TF residuals; this distortion is not, however, responsible for the slope difference from the reference distribution. Because the outliers are easily removed by sigma clipping, we conclude that even in the presence of some tidal distortion, detection of moderate luminosity evolution should be possible with high-redshift samples the size of this 90-galaxy study. (Abridged.)Comment: LaTeX document, 55 pages including 18 figures, to appear in A