138 research outputs found
Clarification of the Nature of the Galaxy CFC97 Cen 05
The galaxy CFC97 Cen 05 has in the past been considered an HI-rich dwarf
galaxy in the nearby Centaurus A group. We have used Australia Telescope
Compact Array observations to show that the HI associated with CFC97 Cen 05 by
Cote et al. (1997) is most likely a Galactic High Velocity Cloud that is
centered ~17' from the optical image of the galaxy. At the optical location of
the galaxy, which is not that tabulated by Banks et al. (1999), there is no
indication of the presence of HI for velocities less than the upper limit of
the HIPASS survey at ~12,500 km/s. In addition, WFPC2 images of CFC97 Cen 05
obtained from the HST Archive reveal that this galaxy is in fact not a dwarf at
all, but rather is a distant background spiral not associated with the
Centaurus A group.Comment: accepted for publication in the PASP (November 2004
The Effect Of A Problem-Based Learning Curriculum On Performance On The Physician Assistant National Certifying Examination
The Effect Of A Problem-Based Learning Curriculum On Performance On The Physician Assistant National Certifying Examination
From Campus to Campus: The Relationship of the University World to the Literary Pastoral Worlds of Edmund Spenser, Phineas Fletcher, and John Milton
Detection of neutral hydrogen in early-type dwarf galaxies of the Sculptor Group
We present our results of deep 21 cm line (HI) observations of five early and
mixed-type dwarf galaxies in the nearby Sculptor group using the ATNF 64m
Parkes Radio Telescope. Four of these objects, ESO294-G010, ESO410-G005,
ESO540-G030, and ESO540-G032, were detected in HI with neutral hydrogen masses
in the range of 2-9x10^5 M_{\odot} ( = 0.08, 0.13, 0.16, and
0.18, respectively). These HI masses are consistent with the gas mass expected
from stellar outflows over a large period of time. Higher resolution radio data
from the Australia Telescope Compact Array were further analysed to measure
more accurate positions and the distribution of the HI gas. In the cases of
dwarfs ESO294-G010 and ESO540-G030, we find significant offsets of 290 pc and
460 pc, respectively, between the position of the HI peak flux and the center
of the stellar component. These offsets are likely to have internal cause such
as the winds from star-forming regions. The fifth object, the spatially
isolated dwarf elliptical Scl-dE1, remains undetected at our 3\sigma limit of
22.5 mJy km/s and thus must contain less than 10^5 M_{\odot} of neutral
hydrogen. This leaves Scl-dE1 as the only Sculptor group galaxy known where no
interstellar medium has been found to date. The object joins a list of similar
systems including the Local Group dwarfs Tucana and Cetus that do not fit into
the global picture of the morphology-density relation where gas-rich dwarf
irregulars are in relative isolation and gas-deficient dwarf ellipticals are
satellites of more luminous galaxies.Comment: 21 pages, 4 figures, to be published in AJ (accepted
The Environmental Influence on the Evolution of Local Galaxies
The results of an Halpha photometric survey of 30 dwarf galaxies of various
morphologies in the Centaurus A and Sculptor groups are presented. Of these 30,
emission was detected in 13: eight are of late-type, two are early-type and
three are of mixed-morphology. The typical flux detection limit of 2e-16 erg
s-1 cm-2, translates into a Star Formation Rate (SFR) detection limit of 4e-6
M_sol yr-1 . In the light of these results, the morphology-density relation is
reexamined: It is shown that, despite a number of unaccounted parameters, there
are significant correlations between the factors determining the morphological
type of a galaxy and its environment. Dwarf galaxies in high density regions
have lower current SFR and lower neutral gas content than their low density
counterparts, confirming earlier results from the Local Group and other denser
environments. The effect of environment is also seen in the timescale formed
from the ratio of blue luminosity to current SFR - dwarfs in higher density
environments have larger values, indicating relatively higher past average SFR.
The influence of environment extends very far and no dwarfs from our sample can
be identified as 'field' objects.Comment: 23 pages, 9 figures, accepted in A
B854: Cost of Producing Milk in Maine: Results from the 2013 Cost-of-Production Survey
The state of Maine has a unique tier-pricing program for dairy farms, established in 2004, which has been funded by milk-handling fees paid by processors. Given the nature of volatile production costs in dairy farming, it is important to update the baseline cost estimates for each tier every three years. This study aims to provide a precise baseline estimate of cost of production for each tier so that state legislators can better manage the tier-pricing program. The authors provide a historic overview of past Maine dairy cost-of-production studies. They analyze the trend of the cost of producing milk in Maine since 2010 using historic data of Maine dairy cost-of-production studies and evaluate their results by comparing them with other dairy cost studies. In general, this empirical study provides a comprehensive assessment of the cost of producing milk in Maine.https://digitalcommons.library.umaine.edu/aes_bulletin/1083/thumbnail.jp
Interstellar medium disruption in the Centaurus A group
We present the results of a 21 cm neutral hydrogen (HI) line detection
experiment in the direction of 18 low luminosity dwarf galaxies of the
Centaurus A group, using the Australia Telescope National Facility 64m Parkes
Radio Telescope and the Australia Telescope Compact Array. Five dwarfs have HI
masses between M_HI=4x10^5 to M_HI=2.1x10^7 Msol and 0.04<M_HI/L_B<1.81 Msol
L_{sol, B}^-1. The other 13 have upper-limits between M_HI<5x10^5 and
M_HI<4x10^6 Msol (M_HI}/L_B<0.24 Msol L_{sol, B}^-1). Two of the
mixed-morphology dwarfs remain undetected in HI, a situation that is in
contrast to that of similar Local Group and Sculptor group objects where all
contain significant amounts of neutral gas. There is a discontinuity in the HI
properties of Centaurus A group low luminosity dwarfs that is unobserved
amongst Sculptor group dwarfs. All objects fainter than M_B=-13 have either
M_HI>10^7 Msol or M_HI<10^6 Msol. This gap may be explained by the ram pressure
stripping mechanism at work in this dense environment where all galaxies with
M_HI<10^7 Msol have been stripped of their gas. The required intergalactic
medium density to achieve this is ~10^-3 cm^-3.Comment: 7 figures, 2 table
Enhancing impact: visualization of an integrated impact assessment strategy
The environmental impact assessment process is over 40 years old and has dramatically expanded. Topics, such as
social, health and human rights impact are now included. The main body of an impact analysis is generally hundreds of
pages long and supported by countless technical appendices. For large, oil/gas, mining and water resources projects both the volume and technical sophistication of the reports has far exceeded the processing ability of host communities. Instead of informing and empowering, the reports are abstruse and overwhelming. Reinvention is required. The development of a visual integrated impact assessment strategy that utilizes remote sensing and spatial analyses is describe
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