2,884 research outputs found
That\u27s All One Mother Can Do
https://digitalcommons.library.umaine.edu/mmb-vp/6418/thumbnail.jp
That\u27s Why We Love You, Betsy Ross
https://digitalcommons.library.umaine.edu/mmb-vp/6367/thumbnail.jp
Flux calibration of the AAO/UKST SuperCOSMOS H-alpha Survey
The AAO/UKST SuperCOSMOS H Survey (SHS) was, when completed in 2003,
a powerful addition to extant wide-field surveys. The combination of areal
coverage, spatial resolution and sensitivity in a narrow imaging band, still
marks it out today as an excellent resource for the astronomical community. The
233 separate fields are available online in digital form, with each field
covering 25 square degrees. The SHS has been the motivation for equivalent
surveys in the north, and new digital H surveys now beginning in the
south such as VPHAS+. It has been the foundation of many important discovery
projects with the Macquarie/AAO/Strasbourg H planetary nebula project
being a particularly successful example. However, the full potential of the SHS
has been hampered by lack of a clear route to acceptable flux calibration from
the base photographic data. We have determined the calibration factors for 170
individual SHS fields, and present a direct pathway to the measurement of
integrated H fluxes and surface brightnesses for resolved nebulae
detected in the SHS. We also include a catalogue of integrated H fluxes
for 100 planetary and other nebulae measured from the SHS, and use these
data to show that fluxes, accurate to 0.10 - 0.14 dex (25-35 per
cent), can be obtained from these fields. For the remaining 63 fields, a mean
calibration factor of 12.0 counts pix R can be used, allowing the
determination of reasonable integrated fluxes accurate to better than 0.2
dex (50 per cent). We outline the procedures involved and the caveats
that need to be appreciated in achieving such flux measurements. This paper
forms a handy reference source that will significantly increase the scientific
utility of the SHS.Comment: 14 pages, 12 figures, 2 tables (plus 7 pp. of supplementary online
information). Version to appear in MNRA
Experimental tests of reaction rate theory: Mu+H2 and Mu+D2
Copyright @ 1987 American Institute of Physics.Bimolecular rate constants for the thermal chemical reactions of muonium (Mu) with hydrogen and deuterium—Mu+H2→MuH+H and Mu+D2→MuD+D—over the temperature range 473–843 K are reported. The Arrhenius parameters and 1σ uncertainties for the H2 reaction are log A (cm3 molecule-1 s-1)=-9.605±0.074 and Ea =13.29±0.22 kcal mol-1, while for D2 the values are -9.67±0.12 and 14.73±0.40, respectively. These results are significantly more precise than those reported earlier by Garner et al. For the Mu reaction with H2 our results are in excellent agreement with the 3D quantum mechanical calculations of Schatz on the Liu–Siegbahn–Truhlar–Horowitz potential surface, but the data for both reactions compare less favorably with variational transition-state theory, particularly at the lower temperatures.NSERC (Canada) and the Petroleum Research Foundation of the Americal Chemical Society
Radio Planetary Nebulae in the Small Magellanic Cloud
We present ten new radio continuum (RC) detections at catalogued planetary
nebula (PN) positions in the Small Magellanic Cloud (SMC): SMPS6, LIN 41, LIN
142, SMP S13, SMP S14, SMP S16, J18, SMP S18, SMP S19 and SMP S22.
Additionally, six SMC radio PNe previously detected, LIN 45, SMP S11, SMPS17,
LIN321, LIN339 and SMPS24 are also investigated (re-observed) here making up a
population of 16 radio detections of catalogued PNe in the SMC. These 16 radio
detections represent ~15 % of the total catalogued PN population in the SMC. We
show that six of these objects have characteristics that suggest that they are
PN mimics: LIN 41, LIN 45, SMP S11, LIN 142, LIN 321 and LIN 339. We also
present our results for the surface brightness - PN radius relation
({\Sigma}-D) of the SMC radio PN population. These are consistent with previous
SMC and LMC PN measurements of the ({\Sigma}-D) relation.Comment: Accepted for publication in Astrophysics and Space Scienc
Non-parametric comparison of histogrammed two-dimensional data distributions using the Energy Test
When monitoring complex experiments, comparison is often made between regularly acquired histograms of data and reference histograms which represent the ideal state of the equipment. With the larger HEP experiments now ramping up, there is a need for automation of this task since the volume of comparisons could overwhelm human operators. However, the two-dimensional histogram comparison tools available in ROOT have been noted in the past to exhibit shortcomings. We discuss a newer comparison test for two-dimensional histograms, based on the Energy Test of Aslan and Zech, which provides more conclusive
discrimination between histograms of data coming from different distributions than methods provided in a recent ROOT release.The Science and Technology Facilities Council, U
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