Black Bear Sideliner, vol. 1, no. 3

Black Bear Sideliner quarterly newsletter produced by UMaine Athletics

3D Integral Field Observations of Ten Galactic Winds - I. Extended phase (>10 Myr) of mass/energy injection before the wind blows

We present 3D spectroscopic observations of a sample of 10 nearby galaxies with the AAOmega-SPIRAL integral field spectrograph on the 3.9m AAT, the largest survey of its kind to date. The double-beam spectrograph provides spatial maps in a range of spectral diagnostics: [OIII] 5007, H-beta, Mg-b, NaD, [OI] 6300, H-alpha, [NII] 6583, [SII] 6717, 6731. All of the objects in our survey show extensive wind-driven filamentation along the minor axis, in addition to large-scale disk rotation. Our sample can be divided into either starburst galaxies or active galactic nuclei (AGN), although some objects appear to be a combination of these. The total ionizing photon budget available to both classes of galaxies is sufficient to ionise all of the wind-blown filamentation out to large radius. We find however that while AGN photoionisation always dominates in the wind filaments, this is not the case in starburst galaxies where shock ionisation dominates. This clearly indicates that after the onset of star formation, there is a substantial delay (> 10 Myr) before a starburst wind develops. We show why this behavior is expected by deriving ``ionisation'' and dynamical timescales for both AGNs and starbursts. We establish a sequence of events that lead to the onset of a galactic wind. The clear signature provided by the ionisation timescale is arguably the strongest evidence yet that the starburst phenomenon is an impulsive event. A well-defined ionisation timescale is not expected in galaxies with a protracted history of circumnuclear star formation. Our 3D data provide important templates for comparisons with high redshift galaxies.[Abridged]Comment: 43 pages, 30 figures, Accepted for publication in ApJ Jan-2010, Full resolution figures available from: http://www.aao.gov.au/AAO/local/www/rgs/work/winds/public/papers/SPIRAL_WINDS_hi-res.htm

Explorations, Vol. 4, No. 1

Articles include: Cover: Old Yarmouth Light, 1960, Cape Forchu, Nova Scotia. By and from the collection of Edgar McKay. The Borderlands Concept: a new look at U.S.-Canada relations, by Victor Konrad and Lauren McKensey Fundy Tidal Power Project, by Gregory White Canadian Poet: Ken Norris Native American Life and Art: a celebration, November, 1986, by Lee-Ann Konrad The Montreal Canadiens: a cultural institution, by James J. Herlan U.S. and Canadian Executives: uses of formal and informal plans in top executive decision-making, by Kent Carter Our Cover Artist: bits and pieces of one man\u27s Nova Scotia, by Edgar McKay The Canadian-American Center and the Canadian Collection of the Fogler Library, by Alice Stewart Capitalist Development in the New England-Atlantic Provinces Region, by Robert H. Babcock Atlantic Canadian Members of Parliament as Representatives, by Howard Cody The Rower and the Pyramid: a tribute to Joe Walsh, by Edward D. Ives The Canadian-American Center: exercise in excellence, by Rand Erb Canadian and Maine Potatoes: a bushel of questions, by George K. Griner, Alan S. Kezis, and James D. Leiby After 20: the Future of the Canadian-American Center, by Victor Konra

Galaxy Group at z=0.3 Associated with the Damped Lyman Alpha System Towards Quasar Q1127-145

(Abridged) We performed a spectroscopic galaxy survey, complete to m<20.3 (L_B>0.15L_B* at z=0.3), within 100x100" of the quasar Q1127-145 (z=1.18). The VLT/UVES quasar spectrum contains three z<0.33 MgII absorption systems. We obtained eight new galaxy redshifts, adding to the four previously known, and galaxy star formation rates and metallicities were computed where possible. A strong MgII system [W_r(2796)=1.8A], which is a known DLA, had three previously identified galaxies; we found two additional galaxies associated with this system. These five galaxies form a group with diverse properties, such as a luminosity range of 0.04<L_B<0.63L_B*, an impact parameter range of 17<D<241kpc and velocity dispersion of 115km/s. The DLA group galaxy redshifts span beyond the 350km/s velocity spread of the metallic absorption lines of the DLA itself. The two brightest group galaxies have SFRs of a few Msun/yr and should not have strong winds. We have sufficient spectroscopic information to directly compare three of the five group galaxies' (emission-line) metallicities with the DLA (absorption) metallicity: the DLA metallicity is 1/10th solar, substantially lower than the three galaxies' which range between less than 1/2 solar to solar metallicity. HST/WFPC-2 imaging shows perturbed morphologies for the three brightest group galaxies, with tidal tails extending 25kpc. We favor a scenario where the DLA absorption originates from tidal debris in the group environment. Another absorber exhibits weak MgII absorption [W_r(2796)=0.03A] and had a previously identified galaxy at a similar redshift. We have identified a second galaxy associated with this system. Both galaxies have solar metallicities and unperturbed morphologies. The SFR of one galaxy is much lower than expected for strong outflows. Finally, we have identified five galaxies at large impact parameters with no associated MgII absorption.Comment: 15 pages, 7 figures, 5 tables. Accepted for publication in MNRAS

On the priming of risk preferences : the role of fear and general affect

Priming is an established tool in psychology for investigating aspects of cognitive processes underlying decision making and is increasingly applied in economics. We report a systematic attempt to test the reproducibility and generalisability of priming effects on risk attitudes in a more diverse population than professionals and students, when priming using either a positive or a negative experience. We further test fear as the causal mechanism underlying countercyclical risk aversion. Across a series of experiments with a total sample of over 1900 participants, we are unable to find any systematic effect of priming on risk preferences. Moreover, our results challenge the role of fear as the mechanism underlying countercyclical risk aversion; we find evidence of an impact of general affect such that the better our participants feel, the more risk they take

On the fraction of star formation occurring in bound stellar clusters

We present a theoretical framework in which bound stellar clusters arise naturally at the high-density end of the hierarchy of the interstellar medium (ISM). Due to short free-fall times, these high-density regions achieve high local star formation efficiencies, enabling them to form bound clusters. Star-forming regions of lower density remain substructured and gas-rich, ending up unbound when the residual gas is expelled. Additionally, the tidal perturbation of star-forming regions by nearby, dense giant molecular clouds imposes a minimum density contrast required for the collapse to a bound cluster. The fraction of all star formation that occurs in bound stellar clusters (the cluster formation efficiency or CFE) follows by integration of these local clustering and survival properties over the full density spectrum of the ISM, and hence is set by galaxy-scale physics. We derive the CFE as a function of observable galaxy properties, and find that it increases with the gas surface density, from ~1% in low-density galaxies to a peak value of ~70% at densities of ~10^3 Msun pc^-2. This explains the observation that the CFE increases with the star formation rate density in nearby dwarf, spiral, and starburst galaxies. Indeed, comparing our model results with observed galaxies yields excellent agreement. The model is applied further by calculating the spatial variation of the CFE within single galaxies. We also consider the variation of the CFE with cosmic time and show that it increases with redshift, peaking in high-redshift, gas-rich disc galaxies. It is estimated that up to 30-35% of all stars in the Universe once formed in bound stellar clusters. We discuss how our theory can be verified with Gaia and ALMA, and provide implementations for future theoretical work and for simulations of galaxy formation and evolution.Comment: 35 pages, 14 figures, 3 tables, accepted by MNRAS (10 August 2012). Fortran and IDL routines for calculating the cluster formation efficiency are publicly available at http://www.mpa-garching.mpg.de/cf

Concern for privacy in relation to age during physical examination of children: an exploratory study

Objectives: To explore whether physicians behave differently regarding ethics and respect for privacydepending on children’s age. We explored whether physician behaviours contributed to childuneasiness.Study design: Observational study of 21 children (0–12 years; 18 boys; mean age 3.2) undergoingevaluation for inguinal hernia. Specific physician-initiated verbal and nonverbal behaviours werecoded from digital video discs of the consultations.Results: Physician intrusiveness (i.e. approaching the child suddenly or in an uninvited way) duringthe physical examination was related to concurrent child uneasiness (r ¼ 0.42, p < 0.06) and lastedthrough the postexamination phase of the consultation (r ¼ 0.52, p < 0.01). Child mood during theexamination strongly predicted postexamination mood (r ¼ 0.69, p < 0.0001). Neither the totalnumber of physician-initiated positive behaviours or privacy-related behaviours was associated withchild age. Negative physician behaviours were strongly related to negative mood in the child(r ¼ 0.72, p < 0.0001) at the close of the consultation