We report the discovery of PSR J1555−2908, a 1.79 ms radio and gamma-ray pulsar in a 5.6 hr binary system with a minimum companion mass of 0.052 M⊙. This fast and energetic ((E =3 ×10(exp 35)) ̇ erg ...s(exp -1) millisecond pulsar was first detected as a gamma-ray point source in Fermi Large Area Telescope (LAT) sky survey observations. Guided by a steep-spectrum radio point source in the Fermi error region, we performed a search at 820 MHz with the Green Bank Telescope that first discovered the pulsations. The initial radio pulse timing observations provided enough information to seed a search for gamma-ray pulsations in the LAT data, from which we derive a timing solution valid for the full Fermi mission. In addition to the discovery and timing of radio and gamma-ray pulsations, we searched for X-ray pulsations using NICER but no significant pulsations were detected. We also obtained time-series r-band photometry that indicates strong heating of the companion star by the pulsar wind. Material blown off the heated companion eclipses the 820 MHz radio pulse during inferior conjunction of the companion for ≈10% of the orbit, which is twice the angle subtended by its Roche lobe in an edge-on system.
Blind Search Methods for Binary Gamma-ray Pulsars Nieder, Lars; Clark, Colin J.; Pletsch, Holger J.
Proceedings of the International Astronomical Union,
09/2017, Letnik:
13, Številka:
S337
Journal Article
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Odprti dostop
Gamma-ray observations by the Fermi Large Area Telescope (LAT) have been used very successfully in the last 9 years to detect more than 200 gamma-ray pulsars. Sixty of these have been found by ...directly searching for pulsations in the gamma-ray data, but only one binary MSP has been found this way. Pulsars in binaries are often difficult to detect in radio data because of large eclipses, and some binary MSPs may even be radio quiet. For those, a gamma-ray blind search might be the only possibility for detection. While searches for isolated pulsars up to kilohertz frequencies are already computationally very challenging, blind searches for binary gamma-ray pulsars are simply infeasible without further knowledge of their orbital parameters. Here we present methods with which we can conduct searches for candidate binary gamma-ray pulsars for which orbital constraints are known from optical observations of a likely companion star. We also highlight some example sources where these methods have been used.
Millisecond pulsars (MSPs) are old neutron stars that spin hundreds of times per second and appear to pulsate as their emission beams cross our line of sight. To date, radio pulsations have been ...detected from all rotation-powered MSPs. In an attempt to discover radio-quiet gamma-ray MSPs, we used the aggregated power from the computers of tens of thousands of volunteers participating in the Einstein@Home distributed computing project to search for pulsations from unidentified gamma-ray sources in Fermi Large Area Telescope data. This survey discovered two isolated MSPs, one of which is the only known rotation-powered MSP to remain undetected in radio observations. These gamma-ray MSPs were discovered in completely blind searches without prior constraints from other observations, raising hopes for detecting MSPs from a predicted Galactic bulge population.
We present 294 pulsars found in GeV data from the Large Area Telescope (LAT) on the Fermi Gamma-ray Space Telescope. Another 33 millisecond pulsars (MSPs) discovered in deep radio searches of LAT ...sources will likely reveal pulsations once phase-connected rotation ephemerides are achieved. A further dozen optical and/or X-ray binary systems co-located with LAT sources also likely harbor gamma-ray MSPs. This catalog thus reports roughly 340 gamma-ray pulsars and candidates, 10% of all known pulsars, compared to \(\leq 11\) known before Fermi. Half of the gamma-ray pulsars are young. Of these, the half that are undetected in radio have a broader Galactic latitude distribution than the young radio-loud pulsars. The others are MSPs, with 6 undetected in radio. Overall, >235 are bright enough above 50 MeV to fit the pulse profile, the energy spectrum, or both. For the common two-peaked profiles, the gamma-ray peak closest to the magnetic pole crossing generally has a softer spectrum. The spectral energy distributions tend to narrow as the spindown power \(\dot E\) decreases to its observed minimum near \(10^{33}\) erg s\(^{-1}\), approaching the shape for synchrotron radiation from monoenergetic electrons. We calculate gamma-ray luminosities when distances are available. Our all-sky gamma-ray sensitivity map is useful for population syntheses. The electronic catalog version provides gamma-ray pulsar ephemerides, properties and fit results to guide and be compared with modeling results.
We report the discovery of PSR J1555-2908, a 1.79 ms radio and gamma-ray pulsar in a 5.6 hr binary system with a minimum companion mass of 0.052 \(M_\odot\). This fast and energetic (\(\dot E = 3 ...\times 10^{35}\) erg/s) millisecond pulsar was first detected as a gamma-ray point source in Fermi LAT sky survey observations. Guided by a steep spectrum radio point source in the Fermi error region, we performed a search at 820 MHz with the Green Bank Telescope that first discovered the pulsations. The initial radio pulse timing observations provided enough information to seed a search for gamma-ray pulsations in the LAT data, from which we derive a timing solution valid for the full Fermi mission. In addition to the radio and gamma-ray pulsation discovery and timing, we searched for X-ray pulsations using NICER but no significant pulsations were detected. We also obtained time-series r-band photometry that indicates strong heating of the companion star by the pulsar wind. Material blown off the heated companion eclipses the 820 MHz radio pulse during inferior conjunction of the companion for ~10% of the orbit, which is twice the angle subtended by its Roche lobe in an edge-on system.
Fermi has detected over 200 pulsars above 100 MeV. In a previous work, using 3 years of LAT data (1FHL catalog) we reported that 28 of these pulsars show emission above 10 GeV; only three of these, ...however, were millisecond pulsars (MSPs). The recently-released Third Catalog of Hard Fermi-LAT Sources (3FHL) contains over 1500 sources showing emission above 10 GeV, 17 of which are associated with gamma-ray MSPs. Using three times as much data as in our previous study (1FHL), we report on a systematic analysis of these pulsars to determine the highest energy (pulsed) emission fromMSPs and discuss the best possible candidates for follow-up observations with ground-based TeV instruments (H.E.S.S., MAGIC, VERITAS, and the upcoming CTA).
Research shows an overrepresentation of trans people in vulnerable socioeconomic situations, primarily due to experiences of discrimination. At the same time, rural or suburban living areas often ...lack specialized trans-related health care, which a majority of trans people rely on to some extent. Taken together, the lack of both socioeconomic resources and access to trans-related health care can exacerbate health-related distress and impairment for trans people. We illustrate this problem using case vignettes of trans people from rural and suburban areas in (Northern) Germany. They are currently participating in an e-health intervention and randomized controlled trial (RCT) called
, whose case vignettes provided the impetus for the scoping review. The scoping review analyzes the impact of place of residence and its intersection with barriers to accessing trans-related health care. PubMed and Web of Science Data bases were searched for relevant studies using a search strategy related to trans people and remote, rural, or suburban residences. 33 studies were selected after full-text screening and supplemented
reference list checks and study team expertise by 12 articles addressing the living conditions of remotely living trans people and describing requirements for trans-related health care. The literature on trans people living remotely reveals intersections of trans mental health with age, race, gender expression, geographic location, community size, socioeconomic status, discrimination experiences, and attitudes towards health care providers. Several structural health care barriers are identified. The role of health care professionals (HCPs) for remotely living trans people is discussed. There is no need assuming that rural life for trans people is inevitably worse for health and well-being than urban life. Nevertheless, some clear barriers and health disparities exist for trans people in remote settings. Empowering trans groups and diversity-sensitive education of remote communities in private and institutional settings are needed for respectful inclusion of trans people. Facilitating access to trans-related health care, such as through video-based e-health programs with HCPs, can improve both the health and socioeconomic situation of trans people.
Many transgender and gender diverse (TGD) people use the internet to find ways out of isolation, network, and share information on health-related topics. Thus, e-health services could reduce the ...health burden of TGD people and facilitate access to health care. Following the PRISMA guidelines, we conducted a systematic review on e-health approaches that could improve trans health care (i.e., services directly for TGD people or training programs for health care professionals, HCPs) and their effectiveness, acceptability, and feasibility. We searched PubMed, Web of Science, and PubPsych databases for publications from January 2000 to June 2021 with final updates before publication. The systematic review identified e-health services across 27 studies from 8 different countries. Few studies evaluated e-health services exclusively for TGD people. However, use of an e-health service was found to be effective and beneficial: TGD people improved in health-related outcomes, and HCPs improved in professional expertise. Service users find e-health services helpful and easy to integrate into their daily lives. Recommendations for further development of e-health services in trans health care are provided. In the future, given the rapidly evolving e-health research and care field, new treatment approaches for TGD people should be subject to ongoing evaluation and development.
Accumulation of soil organic carbon (SOC) may play a key role in climate change mitigation and adaptation. In particular, subsoil provides a great potential for additional SOC storage due to the ...assumed higher stability of subsoil SOC. The fastest way in which SOC reaches the subsoil is via burial, e.g. via erosion or deep ploughing. We assessed the effect of active SOC burial through deep ploughing on long-term SOC stocks and stability in forest and cropland subsoil. After 25-48 years, deep-ploughed subsoil contained significantly more SOC than reference subsoils, in both forest soil (+48%) and cropland (+67%). However, total SOC stocks down to 100 cm in deep-ploughed soil were greater than in reference soil only in cropland, and not in forests. This was explained by slower SOC accumulation in topsoil of deep-ploughed forest soils. Buried SOC was on average 32% more stable than reference SOC, as revealed by long-term incubation. Moreover, buried subsoil SOC had higher apparent radiocarbon ages indicating that it is largely isolated from exchange with atmospheric CO
. We concluded that deep ploughing increased subsoil SOC storage and that the higher subsoil SOC stability is not only a result of selective preservation of more stable SOC fractions.
Getchell RG, George E, Rice AN, Malatos JM, Chambers BM, Griefen A, Nieder C, Rudstam LG. 2022. Effects of ultrasonic control devises on fish. Lake Reserv Manage. 38:240-255.
Harmful algal blooms ...(HABs) can have serious impacts on both ecosystem services and human health, and several mitigation techniques have been developed to control them. Ultrasonic sound sources can disrupt developing algal mats, causing concern that the acoustic energy emitted from these devices may have deleterious health or behavioral effects on nearby fishes. We conducted field and laboratory studies on the effects of ultrasonic control devices on resident fishes. Field observations in Oneida Lake, New York, of the behavioral response of fish to the ultrasonic sound were conducted in shallow water using line transects, and in deeper water using hydroacoustics. No avoidance behavior was detected in either shallow or deep water while the ultrasonic devices were operating. Under controlled laboratory conditions, 7 recreationally or ecologically important fish species and local wild tadpoles were exposed to sound produced by the ultrasonic control devices for a 2 week period. No behavioral effects were noted while fish and tadpoles were monitored during the exposure interval. Finally, no significant or harmful histological or morphological alterations to the skin, fins, gills, or internal organs were observed on either fish or tadpoles when specimens were examined after the 2 week exposure period.
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