964 research outputs found
Design of Optical/IR Blocking Filters for the Lynx X-Ray Microcalorimeter
The Lynx mission concept, under development ahead of the 2020 Astrophysics Decadal Review, includes the Lynx X-ray Microcalorimeter (LXM) as one of its primary instruments. The LXM uses a microcalorimeter array at the focus of a high-throughput soft x-ray telescope to enable high-resolution nondispersive spectroscopy in the soft x-ray waveband (0.2 to 15 keV) with exquisite angular resolution. Similar to other x-ray microcalorimeters, the LXM uses a set of blocking filters mounted within the dewar that pass the photons of interest (x-rays) while attenuating the out-of-band long-wavelength radiation. Such filters have been successfully used on previous orbital and suborbital instruments; however, the Lynx science objectives, which emphasize observations in the soft x-ray band (<1keV), pose more challenging requirements on the set of LXM blocking filters. We present an introduction to the design of the LXM optical/IR blocking filters and discuss recent advances in filter capability targeted at LXM. In addition, we briefly describe the external filters and the modulated x-ray sources to be used for onboard detector calibration
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Contains reports on four research projects.Lincoln Laboratory, Purchase Order DDL-B222U.S. Air Force under Air Force Contract AF19(604)-520
The pediatric asthma yardstick: Practical recommendations for a sustained step-up in asthma therapy for children with inadequately controlled asthma
Sugar and Organic Acid Accumulation in Guard Cells of Vicia faba in Response to Red and Blue Light
A Proper Motion for the Pulsar Wind Nebula G359.23-0.82, "the Mouse," Associated with the Energetic Radio Pulsar J1747-2958
The "Mouse" (PWN G359.23-0.82) is a spectacular bow shock pulsar wind nebula,
powered by the radio pulsar J1747-2958. The pulsar and its nebula are presumed
to have a high space velocity, but their proper motions have not been directly
measured. Here we present 8.5 GHz interferometric observations of the Mouse
nebula with the Very Large Array, spanning a time baseline of 12 yr. We measure
eastward proper motion for PWN G359.23-0.82 (and hence indirectly for PSR
J1747-2958) of 12.9+/-1.8 mas/yr, which at an assumed distance of 5 kpc
corresponds to a transverse space velocity of 306+/-43 km/s. Considering
pressure balance at the apex of the bow shock, we calculate an in situ hydrogen
number density of approximately 1.0(-0.2)(+0.4) cm^(-3) for the interstellar
medium through which the system is traveling. A lower age limit for PSR
J1747-2958 of 163(-20)(+28) kyr is calculated by considering its potential
birth site. The large discrepancy with the pulsar's spin-down age of 25 kyr is
possibly explained by surface dipole magnetic field growth on a timescale ~15
kyr, suggesting possible future evolution of PSR J1747-2958 to a different
class of neutron star. We also argue that the adjacent supernova remnant
G359.1-0.5 is not physically associated with the Mouse system but is rather an
unrelated object along the line of sight.Comment: 8 pages, 4 figures, emulateapj format. Accepted for publication in
The Astrophysical Journa
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