5,818 research outputs found
A Guide to Evaluating Marine Spatial Plans
Marine spatial plans are being developed in over 40 countries around the world, to distribute human activities in marine areas more sustainably and achieve ecological, social, and economic objectives. Monitoring and evaluation are often considered only after a plan has been developed. This guide will help marine planners and managers, monitor and evaluate the success of marine plans in achieving real results and outcomes. This report emphasizes the importance of early integration of monitoring and evaluation in the planning process, the importance of measurable and specific objectives, clear management actions, relevant indicators and targets, and involvement of stakeholders throughout the planning process.
Three Millisecond Pulsars in FERMI LAT Unassociated Bright Sources
We searched for radio pulsars in 25 of the non-variable, unassociated sources
in the Fermi LAT Bright Source List with the Green Bank Telescope at 820 MHz.
We report the discovery of three radio and gamma-ray millisecond pulsars (MSPs)
from a high Galactic latitude subset of these sources. All of the pulsars are
in binary systems, which would have made them virtually impossible to detect in
blind gamma-ray pulsation searches. They seem to be relatively normal, nearby
(<=2 kpc) millisecond pulsars. These observations, in combination with the
Fermi detection of gamma-rays from other known radio MSPs, imply that most, if
not all, radio MSPs are efficient gamma-ray producers. The gamma-ray spectra of
the pulsars are power-law in nature with exponential cutoffs at a few GeV, as
has been found with most other pulsars. The MSPs have all been detected as
X-ray point sources. Their soft X-ray luminosities of ~10^{30-31} erg/s are
typical of the rare radio MSPs seen in X-rays.Comment: Accepted for publication in ApJ Letter
Discovery of Pulsed -rays from PSR J0034-0534 with the Fermi LAT: A Case for Co-located Radio and -ray Emission Regions
Millisecond pulsars (MSPs) have been firmly established as a class of
gamma-ray emitters via the detection of pulsations above 0.1 GeV from eight
MSPs by the Fermi Large Area Telescope (LAT). Using thirteen months of LAT data
significant gamma-ray pulsations at the radio period have been detected from
the MSP PSR J0034-0534, making it the ninth clear MSP detection by the LAT. The
gamma-ray light curve shows two peaks separated by 0.2740.015 in phase
which are very nearly aligned with the radio peaks, a phenomenon seen only in
the Crab pulsar until now. The 0.1 GeV spectrum of this pulsar is well
fit by an exponentially cutoff power law with a cutoff energy of 1.80.1 GeV and a photon index of 1.50.1, first errors are
statistical and second are systematic. The near-alignment of the radio and
gamma-ray peaks strongly suggests that the radio and gamma-ray emission regions
are co-located and both are the result of caustic formation.Comment: 20 pages, 3 figures, 2 tables. Accepted for publication in Ap
Five New Millisecond Pulsars From a Radio Survey of 14 Unidentified Fermi-LAT Gamma-ray Sources
We have discovered five millisecond pulsars (MSPs) in a survey of 14
unidentified Fermi-LAT sources in the southern sky using the Parkes radio
telescope. PSRs J0101-6422, J1514-4946, and J1902-5105 reside in binaries,
while PSRs J1658-5324 and J1747-4036 are isolated. Using an ephemeris derived
from timing observations of PSR J0101-6422 (P =2.57 ms, DM=12 pc cm-3), we have
detected {\gamma}-ray pulsations and measured its proper motion. Its
{\gamma}-ray spectrum (a power law of {\Gamma} = 0.9 with a cutoff at 1.6 GeV)
and efficiency are typical of other MSPs, but its radio and {\gamma}-ray light
curves challenge simple geometric models of emission. The high success rate of
this survey-enabled by selecting {\gamma}-ray sources based on their detailed
spectral characteristics-and other similarly successful searches indicate that
a substantial fraction of the local population of MSPs may soon be known.Comment: 6 pages, 3 figures, 2 tables, accepted by ApJ
Transitioning From Medicaid Expansion Programs to Medicare: Making Sure Low-Income Medicare Beneficiaries Get Financial Help
The Affordable Care Act allows states to offer Medicaid coverage to low-income adults who would not have qualified under previous law. This population will face higher cost-sharing requirements when they transition to Medicare, although some may be eligible for traditional Medicaid benefits and/or Medicare Savings Programs (MSPs) that will reduce their costs. This report discusses how Medicare beneficiaries can qualify for traditional Medicaid and MSPs. It also provides new state data on the number and characteristics of eligible individuals and discusses the potential impact of expanding traditional Medicaid income and asset rules in the Medicaid expansion states. Finally, the report outlines policy options that would make it easier for Medicare beneficiaries to qualify for traditional Medicaid benefits and MSPs
Discovery of an unidentified Fermi object as a black widow-like millisecond pulsar
The Fermi Gamma-ray Space Telescope has revolutionized our knowledge of the
gamma-ray pulsar population, leading to the discovery of almost 100 gamma-ray
pulsars and dozens of gamma-ray millisecond pulsars (MSPs). Although the
outer-gap model predicts different sites of emission for the radio and
gamma-ray pulsars, until now all of the known gamma-ray MSPs have been visible
in the radio. Here we report the discovery of a "radio-quiet" gamma-ray
emitting MSP candidate by using Fermi, Chandra, Swift, and optical
observations. The X-ray and gamma-ray properties of the source are consistent
with known gamma-ray pulsars. We also found a 4.63-hr orbital period in optical
and X-ray data. We suggest that the source is a black widow-like MSP with a
~0.1 solar-mass late-type companion star. Based on the profile of the optical
and X-ray light-curves, the companion star is believed to be heated by the
pulsar while the X-ray emissions originate from pulsar magnetosphere and/or
from intra-binary shock. No radio detection of the source has been reported yet
and although no gamma-ray/radio pulsation has been found, we estimated that the
spin period of the MSP is ~3-5 ms based on the inferred gamma-ray luminosity.Comment: 6 pages, 2 figures; accepted for publication in ApJ
LOFAR discovery of the fastest-spinning millisecond pulsar in the Galactic field
We report the discovery of PSR J09520607, a 707-Hz binary millisecond
pulsar which is now the fastest-spinning neutron star known in the Galactic
field (i.e., outside of a globular cluster). PSR J09520607 was found using
LOFAR at a central observing frequency of 135 MHz, well below the 300 MHz to 3
GHz frequencies typically used in pulsar searches. The discovery is part of an
ongoing LOFAR survey targeting unassociated Fermi Large Area Telescope
-ray sources. PSR J09520607 is in a 6.42-hr orbit around a very
low-mass companion ( M) and we identify a
strongly variable optical source, modulated at the orbital period of the
pulsar, as the binary companion. The light curve of the companion varies by 1.6
mag from at maximum to , indicating that it is
irradiated by the pulsar wind. Swift observations place a 3- upper
limit on the keV X-ray luminosity of erg
s (using the 0.97 kpc distance inferred from the dispersion measure).
Though no eclipses of the radio pulsar are observed, the properties of the
system classify it as a black widow binary. The radio pulsed spectrum of PSR
J09520607, as determined through flux density measurements at 150 and 350
MHz, is extremely steep with (where ).
We discuss the growing evidence that the fastest-spinning radio pulsars have
exceptionally steep radio spectra, as well as the prospects for finding more
sources like PSR J09520607.Comment: 9 pages, 3 figures, 1 table, published in ApJ letter
Discovery of Gamma-ray Pulsations from the Transitional Redback PSR J1227-4853
The 1.69 ms spin period of PSR J1227-4853 was recently discovered in radio
observations of the low-mass X-ray binary XSS J12270-4859 following the
announcement of a possible transition to a rotation-powered millisecond pulsar
state, inferred from decreases in optical, X-ray, and gamma-ray flux from the
source. We report the detection of significant (5) gamma-ray pulsations
after the transition, at the known spin period, using ~1 year of data from the
Large Area Telescope on board the Fermi Gamma-ray Space Telescope. The
gamma-ray light curve of PSR J1227-4853 can be fit by one broad peak, which
occurs at nearly the same phase as the main peak in the 1.4 GHz radio profile.
The partial alignment of light-curve peaks in different wavebands suggests that
at least some of the radio emission may originate at high altitude in the
pulsar magnetosphere, in extended regions co-located with the gamma-ray
emission site. We folded the LAT data at the orbital period, both pre- and
post-transition, but find no evidence for significant modulation of the
gamma-ray flux. Analysis of the gamma-ray flux over the mission suggests an
approximate transition time of 2012 November 30. Continued study of the pulsed
emission and monitoring of PSR J1227-4853, and other known redback systems, for
subsequent flux changes will increase our knowledge of the pulsar emission
mechanism and transitioning systems.Comment: 5 figures, 1 table, accepted for publication in ApJ, updated to
reflect accepted version and add additional coautho
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