Why the extensive use of executive orders by state governors may not be a threat to democracy

Like the president, state Governors frequently make use of executive orders in order to pursue their agendas. But do these unilateral actions undermine democracy? No, argue Alexandra G. Cockerham and Robert E. Crew, Jr, who find that legislatures can be willing to delegate policy-making authority to governors if they are of the same party or if the legislature is fragmented

The Covid-19 pandemic shows the power and limits of American federalism

While there has been a great deal of attention paid to how President Trump has responded to the Covid-19 pandemic, Alexandra Cockerham and Robert E. Crew Jr. argue that, to get a true sense of the country’s response, we should look at the actions of state governors and mayors within states. While the federal government has tried to coordinate some efforts, federalism has meant that governors and local administrators have been able to adapt their responses, with the hardest hit states like New York setting a precedent for others

Precision Pointing of IBEX-Lo Observations

Post-launch boresight of the IBEX-Lo instrument onboard the Interstellar Boundary Explorer (IBEX) is determined based on IBEX-Lo Star Sensor observations. Accurate information on the boresight of the neutral gas camera is essential for precise determination of interstellar gas flow parameters. Utilizing spin-phase information from the spacecraft attitude control system (ACS), positions of stars observed by the Star Sensor during two years of IBEX measurements were analyzed and compared with positions obtained from a star catalog. No statistically significant differences were observed beyond those expected from the pre-launch uncertainty in the Star Sensor mounting. Based on the star observations and their positions in the spacecraft reference system, pointing of the IBEX satellite spin axis was determined and compared with the pointing obtained from the ACS. Again, no statistically significant deviations were observed. We conclude that no systematic correction for boresight geometry is needed in the analysis of IBEX-Lo observations to determine neutral interstellar gas flow properties. A stack-up of uncertainties in attitude knowledge shows that the instantaneous IBEX-Lo pointing is determined to within \sim 0.1\degr in both spin angle and elevation using either the Star Sensor or the ACS. Further, the Star Sensor can be used to independently determine the spacecraft spin axis. Thus, Star Sensor data can be used reliably to correct the spin phase when the Star Tracker (used by the ACS) is disabled by bright objects in its field-of-view. The Star Sensor can also determine the spin axis during most orbits and thus provides redundancy for the Star Tracker.Comment: 22 pages, 18 figure

In flight performance and first results of FREGATE

The gamma-ray detector of HETE-2, called FREGATE, has been designed to detect gamma-ray bursts in the energy range [6-400] keV. Its main task is to alert the other instruments of the occurrence of a gamma-ray burst (GRB) and to provide the spectral coverage of the GRB prompt emission in hard X-rays and soft gamma-rays. FREGATE was switched on on October 16, 2000, one week after the successful launch of HETE-2, and has been continuously working since then. We describe here the main characteristics of the instrument, its in-flight performance and we briefly discuss the first GRB observations.Comment: Invited lecture at the Woods Hole 2001 GRB Conference, 8 pages, 15 figure

HETE-II and the Interplanetary Network

The FREGATE experiment aboard HETE-II has been successfully integrated into the Third Interplanetary Network (IPN) of gamma-ray burst detectors. We show how HETE's timing has been verified in flight, and discuss what HETE can do for the IPN and vice-versa.Comment: To appear in the proceedings of the conference on Gamma-Ray Burst and Afterglow Astronomy 2001: A Workshop Celebrating the First Year of the HETE Mission, to be published by AIP. Figures must be downloaded and printed separatel

Evolving outer heliosphere: Large-scale stability and time variations observed by the Interstellar Boundary Explorer

The first all-sky maps of Energetic Neutral Atoms (ENAs) from the Interstellar Boundary Explorer (IBEX) exhibited smoothly varying, globally distributed flux and a narrow ribbon of enhanced ENA emissions. In this study we compare the second set of sky maps to the first in order to assess the possibility of temporal changes over the 6 months between views of each portion of the sky. While the large-scale structure is generally stable between the two sets of maps, there are some remarkable changes that show that the heliosphere is also evolving over this short timescale. In particular, we find that (1) the overall ENA emissions coming from the outer heliosphere appear to be slightly lower in the second set of maps compared to the first, (2) both the north and south poles have significantly lower (similar to 10-15%) ENA emissions in the second set of maps compared to the first across the energy range from 0.5 to 6 keV, and (3) the knot in the northern portion of the ribbon in the first maps is less bright and appears to have spread and/or dissipated by the time the second set was acquired. Finally, the spatial distribution of fluxes in the southernmost portion of the ribbon has evolved slightly, perhaps moving as much as 6 degrees (one map pixel) equatorward on average. The observed large-scale stability and these systematic changes at smaller spatial scales provide important new information about the outer heliosphere and its global interaction with the galaxy and help inform possible mechanisms for producing the IBEX ribbon

A Characterization of the ALMA Phasing System at 345 GHz

The development of the Atacama Large Millimeter/submillimeter Array (ALMA) phasing system (APS) has allowed ALMA to function as an extraordinarily sensitive station for very long baseline interferometry (VLBI) at frequencies of up to 230 GHz (~1.3 mm). Efforts are now underway to extend use of the APS to 345 GHz (~0.87 mm). Here we report a characterization of APS performance at 345 GHz based on a series of tests carried out between 2015-2021, including a successful global VLBI test campaign conducted in 2018 October in collaboration with the Event Horizon Telescope (EHT).Comment: 22 pages, 11 figures, 7 tables, accepted for publication in PAS

Time-resolved X-ray spectral modeling of an intermediate burst from SGR1900+14 observed by HETE-2/FREGATE and WXM

We present a detailed analysis of a 3.5 s long burst from SGR 1900+14 that occurred on 2001 July 2. The 2-150 keV time-integrated energy spectrum is well described by the sum of two blackbodies whose temperatures are approximately 4.3 and 9.8 keV. The time-resolved energy spectra are similarly well fitted by the sum of two blackbodies. The higher temperature blackbody evolves with time in a manner consistent with a shrinking emitting surface. The interpretation of these results in the context of the magnetar model suggests that the two-blackbody fit is an approximation of an absorbed, multitemperature spectrum expected on theoretical grounds rather than a physical description of the emission. If this is indeed the case, our data provide further evidence for a strong magnetic field and indicate that the entire neutron star was radiating during most of the burst duration