350 research outputs found
Interview of Margaret Mary Markmann, Ph.D.
Dr. Markmann was born in 1948 at the Anderson Hospital in Center City, Philadelphia. She was the fourth of eleven children born into a household of her mother, her father and her grandparents. She grew up in Philadelphia and has lived in the area for her entire life only leaving once after she completed nursing school. During her childhood her extended family lived nearby, her grandmother lived down the street and her Aunt and Uncle lived in the opposite direction. Her father was the direct descendent of Irish immigrants who settled in South West Philadelphia and lived in Southwest Philadelphia for the entirety of their lives. The family also had a summer home in Avalon, New Jersey. Dr. Markmann attended school in one of the largest Catholic Parishes in the United States. There were normally ninety students in the classroom. The school was very large and had 3,300 students attending when she was going to the school. Education was very important for Dr. Markmann and her siblings growing up. Both her father and mother made a point to try and send all eleven of them to college or some form of higher education. After she finished high school she took what she believed was the more practical option as compared to her original desire to become a doctor. Dr. Markmann went to nursing school at St. Joseph’s Hospital School of Nursing in Philadelphia Pennsylvania. She graduated in August 1969 and became a registered nurse. Dr. Markmann worked in the field nursing for a large portion if her professional life. Her first experience was as an emergency room nurse, a position that she held for one year before becoming a Clinical instructor at St. Joseph’s Hospital School of Nursing. She went back to school to get her Bachelor of Arts degree which she received in 1998 from La Salle University with a major in History and a minor in English. She received her Master of Arts from Temple University in 2001. Her original intention was to use that degree to teach high school students. However after she had contacted the Arch Diocese she did not hear back from them for four years. During that time she was contacted to teach a few history courses at La Salle University. That was the start of her professional life at La Salle University. She has been teaching at La Salle University as an adjunct professor since 2002. The majority of the courses that Dr. Markmann teaches at La Salle are Global history courses, most notably HIS 151 and HIS 251. She has also worked in the Dean of Arts and Sciences office as a student advisor for five years, non-consecutively. Many of her children have attended La Salle University and her husband is currently on the Board of Trustees at La Salle. She has been a member of the Parents association at La Salle and both she and her husband have set up the Markmann scholarship for students who attended Catholic School
Discovery of optically faint obscured quasars with Virtual Observatory tools
We use Virtual Observatory (VO) tools to identify optically faint, obscured
(i.e., type 2) active galactic nuclei (AGN) in the two Great Observatories
Origins Deep Survey (GOODS) fields. By employing publicly available X-ray and
optical data and catalogues we discover 68 type 2 AGN candidates. The X-ray
powers of these sources are estimated by using a previously known correlation
between X-ray luminosity and X-ray-to-optical flux ratio. Thirty-one of our
candidates have high estimated powers (Lx > 10^44 erg/s) and therefore qualify
as optically obscured quasars, the so-called ``QSO 2''. Based on the derived
X-ray powers, our candidates are likely to be at relatively high redshifts, z ~
3, with the QSO 2 at z ~ 4. By going ~ 3 magnitudes fainter than previously
known type 2 AGN in the two GOODS fields we are sampling a region of redshift -
power space which was previously unreachable with classical methods. Our method
brings to 40 the number of QSO 2 in the GOODS fields, an improvement of a
factor ~ 4 when compared to the only 9 such sources previously known. We derive
a QSO 2 surface density down to 10^-15 erg/cm^2/s in the 0.5 - 8 keV band of >~
330/deg^2, ~ 30% of which is made up of previously known sources. This is
larger than current estimates and some predictions and suggests that the
surface density of QSO 2 at faint flux limits has been underestimated. This
work demonstrates that VO tools are mature enough to produce cutting-edge
science results by exploiting astronomical data beyond ``classical''
identification limits (R <~ 25) with interoperable tools for statistical
identification of sources using multiwavelength information.Comment: 16 pages, 6 figures, accepted for publication in Astronomy &
Astrophysics. PDF file with higher resolution figures available at
http://www.eso.org/~ppadovan/AVO-paper.pd
The Chandra Deep Field-North Survey. XIV. X-ray detected Obscured AGNs and Starburst Galaxies in the Bright Submm Source Population
We provide X-ray constraints and perform the first X-ray spectral analyses
for bright (f_850>=5mJy; S/N>=4) SCUBA sources in an 8.4'x8.4' area of the 2 Ms
Chandra Deep Field-North survey containing the Hubble Deep Field-North. X-ray
emission is detected from 7 of the 10 bright submm sources in this region,
corresponding to an X-ray detected submm source density of ~360 deg^-2 (>~36%
of the bright submm source population). Two of the X-ray detected sources have
nearby (within 3") X-ray companions, suggesting merging/interacting sources or
gravitational lensing effects, and 3 lie within the approximate extent of a
proto-cluster candidate. Five of the X-ray detected sources have flat X-ray
spectral slopes, suggesting obscured AGN activity. X-ray spectral analyses
suggest that one of these AGNs may be a Compton-thick source; of the other 4
AGNs, 3 appear to be Compton-thin sources and one has poor constraints. The
rest-frame unabsorbed X-ray luminosities of these AGNs are more consistent with
those of Seyfert galaxies than QSOs. Thus, the low X-ray detection rate of
bright submm sources by moderately deep X-ray surveys appears to be due to the
relatively low luminosities of the AGNs rather than Compton-thick absorption. A
comparison of these sources to the well-studied heavily obscured AGN NGC6240
shows that the average AGN contribution is negligible at submm wavelengths. The
X-ray properties of the other 2 X-ray detected sources are consistent with
those expected from luminous star formation; however, we cannot rule out the
possibility that low-luminosity AGNs are present. The 3 X-ray undetected
sources appear to lie at high redshift (z>4) and could be either AGNs or
starbust galaxies.Comment: AJ in press (February 2003), 16 pages, includes emulateapj5.st
A Semi-Empirical Model of the Infrared Emission from Galaxies
We present a semi-empirical model for the infrared emission of dust around
star-forming sites in galaxies. Our approach combines a simple model of
radiative transfer in dust clouds with a state-of-the-art model of the
microscopic optical properties of dust grains pioneered by Draine & Li. In
combination with the Starburst 99 stellar spectral synthesis package, this
framework is able to produce synthetic spectra for galaxies which extend from
the Lyman limit through to the far-infrared. We use it to probe how model
galaxy spectra depend upon the physical characteristics of their dust grain
populations, and upon the energy sources which heat that dust. We compare the
predictions of our model with the 8- and 24-micron luminosities of sources in
the Spitzer First Look Survey, and conclude by using the models to analyse the
relative merits of various colour diagnostics in distinguishing systems out to
a redshift of 2 with ongoing star formation from those with only old stellar
populations.Comment: 15 pages, 16 figures, 2 tables. Accepted for publication in MNRA
Radio Observations of the Hubble Deep Field South Region IV: Optical Properties of the Faint Radio Population
The Australia Telescope Hubble Deep Field-South (ATHDFS) survey of the Hubble
Deep Field South reaches sensitivities of ~10 miceoJyJy at 1.4, 2.5, 5.2 and
8.7 GHz, making the ATHDFS one of the deepest surveys ever performed with the
Australia Telescope Compact Array. Here we present the optical identifications
of the ATHDFS radio sources using data from the literature. We find that ~66%
of the radio sources have optical counterparts to I = 23.5 mag. Deep HST
imaging of the area identifies a further 12% of radio sources. We present new
spectroscopic observations for 98 of the radio sources, and supplement these
spectroscopic redshifts with photometric ones calculated from 5-band optical
imaging. The host galaxy colors and radio-to-optical ratios indicate that low
luminosity (or "radio quiet") AGN make up a significant proportion of the
sub-mJy radio population, a result which is in accordance with a number of
other deep radio studies. The radio-to-optical ratios of the bright (S_1.4GHz >
1 mJy) sources is consistent with a bimodal distribution.Comment: accepted for publication in A
Obscured and powerful AGN and starburst activities at z~3.5
We report the discovery of two sources at z=3.867 and z=3.427 that exhibit
powerful starburst and AGN activities. They benefit from data from radio to X
rays from the CFHTLS-D1/SWIRE/XMDS surveys. Follow-up optical and near-infrared
spectroscopy, and millimeter IRAM/MAMBO observations are also available. We
performed an analysis of their spectral energy distributions to understand the
origin of their emission and constrain their luminosities. A comparison with
other composite systems at similar redshifts from the literature is also
presented. The AGN and starburst bolometric luminosities are ~10^13 Lsun. The
AGN emission dominates at X ray, optical, mid-infrared wavelengths, and
probably in the radio. The starburst emission dominates in the far-infrared.
The estimated star formation rates range from 500 to 3000Msun/yr. The AGN
near-infrared and X ray emissions are heavily obscured in both sources with an
estimated dust extinction Av>4, and Compton-thick gas column densities. The two
sources are the most obscured and most luminous AGNs detected at millimeter
wavelengths currently known. The sources presented in this work are heavily
obscured QSOs, but their properties are not fully explained by the standard AGN
unification model. In one source, the ultraviolet and optical spectra suggest
the presence of outflowing gas and shocks, and both sources show emission from
hot dust, most likely in the vicinity of the nucleus. Evidence of moderate
AGN-driven radio activity is found in both sources. The two sources lie on the
local M_BH-M_bulge relation. To remain on this relation, their star formation
rate has to decrease. Our results support evolutionary models that invoke radio
feedback as star formation quenching mechanism, and suggest that such a
mechanism might play a major role also in powerful AGNs.Comment: Accepted for publication in Astronomy & Astrophysics (12 pages; 6
figures); replaced version includes minor language editing and revised
reference
Genesis of the dusty Universe: modeling submillimetre source counts
We model the evolution of IR galaxies using a phenomenological approach to
match the observed source counts at different IR wavelengths. We introduce a
new algorithm for reproducing source counts based on direct integration of
probability distributions rather than Monte-Carlo sampling. We construct a
simple model for the evolution of the luminosity function and the colour
distribution of IR galaxies which utilizes a minimum number of free parameters.
Moreover we analyze how each of these parameters is constrained by
observational data. The model is based on pure luminosity evolution and adopts
the Dale & Helou SED templates. We find that the 850um source counts and their
redshift distribution depend strongly on the shape of the luminosity evolution
function, but only weakly on the details of the SEDs. We derive the best-fit
evolutionary model using the 850um counts and redshift distribution as
constraints. Moreover our best-fit shows a flattening of the faint end of the
luminosity function towards high redshifts and requires a colour evolution
which implies the typical dust temperatures of objects with the same
luminosities to decrease with redshift. We compare our best-fit model to
observed source counts at shorter and longer wavelengths which indicates our
model reproduces the 70um and 1100um source counts remarkably well, but
under-produces the counts at intermediate wavelengths. Analysis reveals that
the discrepancy arises at low redshifts, indicating that revision of the
adopted SED library towards lower dust temperatures (at a fixed infrared
luminosity) is required. This modification is equivalent to a population of
cold galaxies existing at low redshifts, as also indicated by recent Herschel
results, which are underrepresented in IRAS sample. We show that the modified
model successfully reproduces the source counts in a wide range of IR and submm
wavelengths.Comment: 21 pages, 11 figures, 2 tables. Accepted for publication in MNRAS.
Supplementary information could be found at
http://www.strw.leidenuniv.nl/genesis
High Resolution Studies of Radio Sources in the Hubble Deep and Flanking Fields
Eighteen days of MERLIN data and 42 hours of A-array VLA data at 1.4 GHz have
been combined to image a 10-arcmin field centred on the Hubble Deep and
Flanking Fields (HDF and HFF). A complete sample of 92 radio sources with
1.4-GHz flux densities above 40 microJy has been imaged using MERLIN+VLA. The
images are amongst the most sensitive yet made at 1.4 GHz, with rms noise
levels of 3.3 microJy/beam in the 0.2-arcsec images. Virtually all the sources
are resolved, with angular sizes in the range 0.2 to 3 arcsec. No additional
sources were detected down to 23 microJy in the central 3 arcmin, indicating
that sources fainter than 40 microJy are heavily resolved with MERLIN and must
have typical angular sizes greater than 0.5 arcsec. Compact radio sources were
used to align the optical data to the ICRF, to <50 mas in the HDF. We find a
statistical association of very faint (2 microJy and above) radio sources with
optically bright HDF galaxies down to about 23 mag. Of the 92 radio sources
above 40 microJy, about 85 percent are identified with galaxies brighter than
about I = 25 mag; the remaining 15 percent are associated with optically faint
systems. We identify several very red, optically faint systems including the
the strongest sub-mm source in the HDF, HDF850.1. 72 percent of the radio
sources are starburst or AGN-type systems; the remainder are unclassified. The
proportion of starburst systems increases with decreasing flux density; below
100 microJy 70 percent of the sources are starburst-type systems in the
redshift range 0.3 -- 1.3. Chandra detections are associated with 55 of the 92
radio sources but their X-ray flux densities do not appear to be correlated
with the radio flux densities or morphologies.Comment: Accepted by MNRAS Jan 2005 34 pp with inline b/w figures plus 9 pp of
colour figures All material is available from http://www.merlin.ac.uk/HDF/ as
gzipped PDFs. ME547.pdf.gz - main paper ME547_Appendix_C1.pdf.gz,
ME547_Appendix_C2.pdf.gz - colour figures All figures are also available in
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Cancer incidence patterns by region and socioeconomic deprivation in teenagers and young adults in England
Data on 35 291 individuals with cancer, aged 13–24 years, in England from 1979 to 2001 were analysed by region and socio-economic deprivation of census ward of residence, as measured by the Townsend deprivation index. The incidence of leukaemia, lymphoma, central nervous system tumours, soft tissue sarcomas, gonadal germ cell tumours, melanoma and carcinomas varied by region (P<0.01, all groups) but bone tumour incidence did not. Lymphomas, central nervous system tumours and gonadal germ cell tumours all had higher incidence in less deprived census wards (P<0.01), while chronic myeloid leukaemia and carcinoma of the cervix had higher incidence in more deprived wards (P<0.01). In the least deprived wards, melanoma incidence was nearly twice that in the most deprived, but this trend varied between regions (P<0.001). These cancer incidence patterns differ from those seen in both children and older adults and have implications for aetiology and prevention
Extragalactic Results from the Infrared Space Observatory
More than a decade ago the IRAS satellite opened the realm of external
galaxies for studies in the 10 to 100 micron band and discovered emission from
tens of thousands of normal and active galaxies. With the 1995-1998 mission of
the Infrared Space Observatory the next major steps in extragalactic infrared
astronomy became possible: detailed imaging, spectroscopy and
spectro-photometry of many galaxies detected by IRAS, as well as deep surveys
in the mid- and far- IR. The spectroscopic data reveal a wealth of detail about
the nature of the energy source(s) and about the physical conditions in
galaxies. ISO's surveys for the first time explore the infrared emission of
distant, high-redshift galaxies. ISO's main theme in extragalactic astronomy is
the role of star formation in the activity and evolution of galaxies.Comment: 106 pages, including 17 figures. Ann.Rev.Astron.Astrophys. (in
press), a gzip'd pdf file (667kB) is also available at
http://www.mpe.mpg.de/www_ir/preprint/annrev2000.pdf.g
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