(PhysOrg.com) — HP’s mysterious new smartphone entrants have just been revealed. The HP Voice Messenger will sell for €399 ($532) on November 5th and the Data Messenger will be selling for €499 ($665) on November 22nd. The two models will be available either SIM-free through HP resellers, or with a wireless contract through Vodafone Europe-wide. Citation: HP Reveals Their Ipaq Data Manager & Voice Messenger Smartphones (2008, October 21) retrieved 18 August 2019 from https://phys.org/news/2008-10-hp-reveals-ipaq-voice-messenger.html This document is subject to copyright. Apart from any fair dealing for the purpose of private study or research, no part may be reproduced without the written permission. The content is provided for information purposes only. HP Unveils iPAQ 500 Smartphone Explore further The HP Ipaq Data Manager smartphone is a Windows Mobile 6.1 Professional device which features a slide-out keyboard, 2.8 inch QVGA screen, WiFi, Bluetooth, Quadband GSM, Tri-band 7.2 Mbps HSDPA (European bands), HSUPA, A-GPS and a 3.1 Megapixel camera with LED flash. There is also 128 MB RAM and 256 MB ROM, supports microSD expansion and comes with a 1140 mAh battery.The Data Manager smartphone is 160g and 5.7 x 1.74 x 11.4 cm, and has a 2.5mm headphone jack. The phone is bundled with Opera Mobile, Google maps mobile and comes with a 30 Day Trial of Webraska Turn-by-Turn Navigation.The HP Ipaq Voice Messenger has similar specs to the Data Manager, but instead of the slide-out keyboard it has a 20 key suretype-style keyboard. The non-touchscreen Windows Mobile 6.1 Standard device has a 2.4 inch QVGA screen. The connectivity and GPS is the same, but the device is much lighter at 107 g and measures 5.0 x 1.36 x 11.4 cm. This smartphone comes with a larger 1260 mAh Lithium-Polymer battery.Both smartphones feature micro-USB ports for synchronization and a new optical sensor that replaces the five-way navigator key common to many phone designs. You navigate through the menus by just gliding your thumb over the disk, and tapping it when you want to select something.Both models have a power saving mode that minimizes power consumption if the battery charge level starts to get low while the user is out on the road. HP said that the iPaq Voice Messenger is aimed at users that want a phone for voice calls first, but who may also need to receive emails while on the go.
Month: August 2019
Explore further © 2010 PhysOrg.com Sharp Develops Mass-Production Technology for Triple-Junction Thin-Film Solar Cells This document is subject to copyright. Apart from any fair dealing for the purpose of private study or research, no part may be reproduced without the written permission. The content is provided for information purposes only. (PhysOrg.com) — Sanyo has announced its development of the world’s most energy efficient solar module, the HIT-N230. The module was unveiled at a press conference run by Sanyo Electric’s Solar Division. Citation: Sanyo announces world’s most efficient solar module (2010, June 16) retrieved 18 August 2019 from https://phys.org/news/2010-06-sanyo-world-efficient-solar-module.html Sanyo is a major manufacturer of solar panels, with three factories in Japan, one in Hungary serving Europe, and a fifth in Mexico that serves the US market. The N series of modules are produced in Japan and consist of solar cells of the Hetero-junction with Intrinsic Thin-layer (HIT) type.HIT solar cells contain a single thin crystalline wafer of silicon surrounded by ultra-thin amorphous layers of silicon. They are characterized by high efficiency at high temperatures, and increased output power even during high summertime temperatures. The high conversion efficiency of HIT cells means more capacity can be installed compared to conventional crystalline silicon solar cells.The new N230 solar cell module is claimed to have an energy conversion efficiency of 20.7 percent, which makes it the most efficient solar module produced so far. The unprecedented efficiency was achieved by increasing the number of solar cell tabs from two to three and making each tab thinner. They also applied AG coated glass to the cells, and this reduces the amount of scattering and reflection of light. The increase in energy conversion efficiency could make the solar modules useful in areas with less than ideal amounts of sunshine. Sanyo is already one of the leading manufacturers of solar cells and modules, and the company is currently expanding its solar cell module production at Kaizuka City and Ohtsu City in Japan in response to increased demand. In total Sanyo plans to nearly double its HIT solar cell production from the current level of 340 MW to 600 MW by March next year.National and local installation subsidies in Japan have seen the local market expand rapidly, and this has also been helped by the national government’s new program for purchasing surplus electricity generated by solar installations.The 230W model N230 and 225W N225 will both be officially launched in Japan in autumn this year and in Europe in 2011.
© 2011 PhysOrg.com The international team of scientists, led by Dr Ehab Abouheif of the Department of Biology at McGill University in Montreal, Canada, looked at the genomes of two ant species that produce supersoldiers. They identified the genetics behind the supersoldier caste and were able to activate the genes by treating ant larvae with methoprene, a growth hormone. As expected, the ant larvae became supersoldiers.They then treated in the same way larvae of Pheidole morrisi, an ant species which lives in New York and that does not normally produce supersoldiers, but which lead author, Dr Abouheif, had previously noted produced large-headed ants resembling supersoldiers on rare occasions. The treated larvae grew to become large headed and jawed ants resembling supersoldiers. The same effect was produced in two other Pheilode species, which are not known to produce supersoldiers.Dr Abouheif and colleagues report, in their paper published in the journal Science, that ant larvae normally develop into soldiers or workers depending on the levels of the “juvenile hormone”: if levels are high the ants become soldiers, while if they are low they become the smaller worker ants. In the species that produce supersoldiers there is a second high threshold of the juvenile hormone, above which the larvae develop into the larger supersoldiers. The growth hormone methoprene, used in the experiments, mimics the effects of juvenile hormone.The results of the experiments suggest that even those species that do not produce supersoldiers must have been able to do so in the distant past, some 35 to 60 million years ago, and that they still retain the genetic information for supersoldier production that can be reactivated under certain environmental or nutritional states. The researchers say that retaining the ancestral genetic tools could be important for the evolution of new physical traits. Supersoldier ants occur naturally in species found in Mexico and the south-west of the USA. They were also known in ancestral species, and Abouheif and the team suggest the common ancestor of the entire Pheidole genus had the ability to produce supersoldiers. It is not known why only eight of the species retain the ability and the remainder simply abandon the nests if they are invaded by predatory army ants, but Abouheif said the genes might have been repeatedly reactivated. This would explain anomalies such as the rare instances of supersoldiers he noted in the P. morrisi ants, which is a species not threatened by army ants.Dr. Abouheif and colleagues think that their work in unlocking ancestral features could find application in fields such as agriculture, where it might be used to breed crops with greater nutritional value. Abouheif also suggests the work might also shed some light on the growth of cancers, which he said could be “the unleashing of some kind of ancestral potential,” which might be reversible if it could be identified. This document is subject to copyright. Apart from any fair dealing for the purpose of private study or research, no part may be reproduced without the written permission. The content is provided for information purposes only. Death from above: Parasite wasps attacking ants from the air filmed for the first time A supersoldier communicates with a minor worker from the hyper-diverse ant genus Pheidole. Photo courtesy of Alex Wild/alexanderwild.com (PhysOrg.com) — There are over 1100 species of Pheidole genus ants, and most individual ants belong to either the worker or soldier caste. In only eight of the Pheidole species, some individuals can belong to a “supersoldier” subcaste instead, and these ants fight off predatory army ant species and bar their way by blocking off the entrances to the nest using their over-sized heads. Now, scientists have managed to create supersoldiers in other species by reactivating ancestral genes. Journal information: Science More information: Ancestral Developmental Potential Facilitates Parallel Evolution in Ant, Science 6 January 2012: Vol. 335 no. 6064 pp. 79-82. DOI:10.1126/science.1211451ABSTRACTComplex worker caste systems have contributed to the evolutionary success of advanced ant societies; however, little is known about the developmental processes underlying their origin and evolution. We combined hormonal manipulation, gene expression, and phylogenetic analyses with field observations to understand how novel worker subcastes evolve. We uncovered an ancestral developmental potential to produce a “supersoldier” subcaste that has been actualized at least two times independently in the hyperdiverse ant genus Pheidole. This potential has been retained and can be environmentally induced throughout the genus. Therefore, the retention and induction of this potential have facilitated the parallel evolution of supersoldiers through a process known as genetic accommodation. The recurrent induction of ancestral developmental potential may facilitate the adaptive and parallel evolution of phenotypes. Citation: Supersoldier ants created in the lab by reactivating ancestral genes (2012, January 6) retrieved 18 August 2019 from https://phys.org/news/2012-01-supersoldier-ants-lab-reactivating-ancestral.html Explore further
One such speaker is Susan Hough—she’s with the US Geological Survey. She reported to those in attendance that prior to the invention and implementation of seismometers, evidence of earthquakes could be found only through earlier anecdotal writings. But such records, she notes, tended to underestimate the size of the quakes being described. Suddenly, she says, after 1900, earthquakes started getting bigger.They didn’t get bigger of course, what she meant was that the size perception of earlier earthquakes had been underestimated—many might not be in the historical record at all. Part of the problem, she explained, was that until fairly recently, it was believed that all earthquakes of a certain large size, produced tsunami’s, which of course tend to show up in written records.The problem with relying on underestimated data, she also explained, is that it causes modern day planners to underestimate what is likely to happen in the future. She notes that one example was that of the Kamchatka quake that occurred in 1841 in Russia. The record shows it to have been an 8.3 magnitude quake, but closer scrutiny suggests that estimate was wrong—reports of a tsunami in Hawaii at the time, indicate it was almost certainly much stronger, perhaps as high as magnitude 9.2.Roger Musson of the British Geological Survey concurred, noting that people were taken almost completely by surprise when the Fukushima quake struck in 2011. But, looking back, it’s clear that one almost exactly like it struck in the same place back in the 9th century. He noted virtually the same thing can be said for the Haiti quake that struck in 2010.The overall point the geologists are trying to make is that it’s likely that the reported numbers and sizes of quakes described in the past are in error, and thus, using them as guides for the future is both risky and ill-advised as the lives of people in many at-risk areas may be depending on more accurate assessments. © 2013 Phys.org (Phys.org) —Several geologists from around the world are presenting a case for missing or underreported earthquakes at this year’s American Geophysical Union Fall meeting being held in San Francisco. They suggest that faulty or missing data from before 1900 might be leading to underestimations of the numbers of big quakes to expect in the future. Explore further 6.5 magnitude quake off Alaska’s Aleutian Islands Aerial photo of the San Andreas Fault in the Carrizo Plain, northwest of Los Angeles. Credit: Wikipedia. Citation: Geologists report that risks of big earthquakes may be underestimated (2013, December 12) retrieved 18 August 2019 from https://phys.org/news/2013-12-geologists-big-earthquakes-underestimated.html More information: fallmeeting.agu.org/2013/ This document is subject to copyright. Apart from any fair dealing for the purpose of private study or research, no part may be reproduced without the written permission. The content is provided for information purposes only.
(Phys.org)—A team of researchers with members from institutions in Spain, France and Egypt has demonstrated that hydrogen atoms on graphene yield a magnetic moment and furthermore, that such moments can order ferromagnetically over relatively large distances. In their paper published in the journal Science the group describes experiments they carried out in attempting to cause a sheet of graphene to become magnetic, how they found evidence that it was possible using hydrogen atoms, and the ways such a material might be used in industrial applications. Shawna Hollen with the University of New Hampshire, and Jay Gupta with Ohio State University, offer some insights into the work done by the team in the same journal issue with a Perspectives piece—they also outline the hurdles that still need to be overcome before magnetic graphene might be used in real applications. A picture of hydrogen atoms in graphene. Credit: CIC nanoGUNE Credit: AlexanderAlUS/Wikipedia/CC BY-SA 3.0 More information: H. Gonzalez-Herrero et al. Atomic-scale control of graphene magnetism by using hydrogen atoms, Science (2016). DOI: 10.1126/science.aad8038AbstractIsolated hydrogen atoms absorbed on graphene are predicted to induce magnetic moments. Here we demonstrate that the adsorption of a single hydrogen atom on graphene induces a magnetic moment characterized by a ~20–millielectron volt spin-split state at the Fermi energy. Our scanning tunneling microscopy (STM) experiments, complemented by first-principles calculations, show that such a spin-polarized state is essentially localized on the carbon sublattice opposite to the one where the hydrogen atom is chemisorbed. This atomically modulated spin texture, which extends several nanometers away from the hydrogen atom, drives the direct coupling between the magnetic moments at unusually long distances. By using the STM tip to manipulate hydrogen atoms with atomic precision, it is possible to tailor the magnetism of selected graphene regions. Explore further Citation: Researchers demonstrate hydrogen atoms on graphene yield a magnetic moment (2016, April 22) retrieved 18 August 2019 from https://phys.org/news/2016-04-hydrogen-atoms-graphene-yield-magnetic.html This document is subject to copyright. Apart from any fair dealing for the purpose of private study or research, no part may be reproduced without the written permission. The content is provided for information purposes only. © 2016 Phys.org Graphene’s superior qualities as a material have been well documented, though one of its drawbacks has not been highlighted as much—it is not magnetic. If it were, it could conceivably be used in many more applications. That has led to efforts to do things to a sheet of graphene that would cause it to become magnetic, one of which is by adding hydrogen atoms to its surface, creating what has been called graphane. Unfortunately, stability has been an issue, making the process difficult to control. In this new effort, the researchers have taken a different approach—they took advantage of the fact that magnetism occurs in graphene when an imbalance occurs in two sub-lattices that are part of the whole— that means the number of atoms that exist in an individual sublattice can be caused to be unequal due to such things as point defects or geometric shape. That allows a hydrogen adatom to bond with a carbon pz-orbital. The end result is magnetic moments being formed in the honeycomb lattice, with such moments aligning ferromagnetically when they are on the same sublattice, and antiferromagnetically when they are on an opposing sublattice.Such a material, Hollen and Gupta note, might allow for storing information at much higher densities than has ever been seen before, but before that can happen, they also note, several hurdles must be overcome, such as realizing atomic scale precision with the process on a large scale. Journal information: Science A new way to make higher quality bilayer graphene
This document is subject to copyright. Apart from any fair dealing for the purpose of private study or research, no part may be reproduced without the written permission. The content is provided for information purposes only. Citation: Small long-serving satellite observes ammonia emission from the center of our galaxy (2017, January 16) retrieved 18 August 2019 from https://phys.org/news/2017-01-small-long-serving-satellite-ammonia-emission.html Odin was launched on February 20, 2001 with the aim of studying the depletion of the ozone layer in the atmosphere and searching for water and oxygen in interstellar space. With a mass of about 250 kilograms, the spacecraft has dimensions of 2.0 x 1.1 meters (3.8 meters when fully deployed in orbit). The satellite is equipped with an advanced radiometer using a 1.1-meter telescope and a spectrograph, called the Optical Spectrograph and Infrared Imaging System (OSIRIS).Odin was originally designed to be operational for about two years, but the spacecraft is still in good health and is currently functioning nominally. During the astrophysics part of its mission, the satellite has observed water in comets and detected molecular oxygen in interstellar clouds. Now, a team of Swedish researchers that includes Odin mission scientists has presented new results proving that the spacecraft can still conduct significant detections.”Recently, Odin has made complementary observations of the 572 GHz NH3 line towards the Sgr A +50 km s−1 cloud and circumnuclear disk (CND). (…) Significant NH3 emission has been observed in both the +50 km s−1 cloud and the CND. Clear NH3 absorption has also been detected in many of the spiral arm features along the line of sight from the sun to the core of our galaxy,” the scientists wrote in the paper.The observations were carried out in April 2015 and April 2016 as part of a larger survey studying the Sagittarius A complex radio source consisting of Sgr A*, the supernova remnant Sagittarius A East and the spiral structure Sagittarius A West.According to the paper, the spacecraft detected a very large velocity width (80 km s−1) of the ammonia emission associated with the shock region in the southwestern part of the CND. The researchers propose that it may suggest a formation scenario similar to that of gas-phase water in shocks and outflows.”The very high gas-phase water abundance determined for the shock region at CND SW by Karlsson et al. (2015) is similar to that found in the red-ward high-velocity wings of the Sgr A molecular clouds, and likely results from shock heating causing release of pre-existing grain surface water, possibly combined with high temperature shock chemistry,” the paper reads.The authors concluded that the high-quality spectra obtained by Odin clearly demonstrate the satellite’s continuing capabilities. It shows that it is possible to build a comparatively cheap, but complicated spacecraft that can remain in high quality operation for a long mission lifetime. © 2017 Phys.org More information: Odin observations of ammonia in the Sgr A +50 km/s Cloud and Circumnuclear Disk, arXiv:1701.02536 [astro-ph.GA] arxiv.org/abs/1701.02536AbstractContext. The Odin satellite is now into its sixteenth year of operation, much surpassing its design life of two years. One of the sources which Odin has observed in great detail is the Sgr A Complex in the centre of the Milky Way. Aims. To study the presence of NH3 in the Galactic Centre and spiral arms. Methods. Recently, Odin has made complementary observations of the 572 GHz NH3 line towards the Sgr A +50 km/s Cloud and Circumnuclear Disk (CND). Results. Significant NH3 emission has been observed in both the +50 km/s Cloud and the CND. Clear NH3 absorption has also been detected in many of the spiral arm features along the line of sight from the Sun to the core of our Galaxy. Conclusions. The very large velocity width (80 km/s) of the NH3 emission associated with the shock region in the southwestern part of the CND may suggest a formation/desorption scenario similar to that of gas-phase H2O in shocks/outflows. (Phys.org)—Completing its 16th year in orbit, a small Swedish astrophysics and aeronomy satellite named “Odin” has proven that it is still capable of carrying out important observations of space. The spacecraft has lately observed ammonia (NH3) emissions from an astronomical radio source known as Sagittarius A* (Sgr A* for short) at the center of the Milky Way galaxy. The results of these observations were published January 10 in a paper available on arXiv.org. Astronomers discover molecular and atomic clouds associated with a superbubble in LMC Explore further Artist’s rendition of the Odin spacecraft in orbit. Credit: SNSB
Citation: Radio emission detected from a gamma-ray pulsar (2017, July 5) retrieved 18 August 2019 from https://phys.org/news/2017-07-radio-emission-gamma-ray-pulsar.html © 2017 Phys.org Astronomers discover bubble-like structure associated with the pulsar PSR J1015−5719 This document is subject to copyright. Apart from any fair dealing for the purpose of private study or research, no part may be reproduced without the written permission. The content is provided for information purposes only. Gamma-ray pulsars are rotating neutron stars emitting gamma-ray photons. Some of them also showcase radio emission that is often difficult to detect. This is most probably due to the fact that their narrow radio beams miss the sightline towards Earth.Located nearly 2,000 light years away from the Earth, J1732−3131 has a rotation period of about 196 milliseconds and is one such gamma-ray pulsar with hart-to-identify radio emission. The pulsar was found thanks to the data provided by the large area telescope (LAT) onboard NASA’s Fermi Gamma-ray Space Telescope. So far, only a faint radio signal from this pulsar was detected at 34 MHz in 2012.More recently, Maan’s team, motivated by previous faint detections, conducted follow-up observations of J1732−3131 between March 2014 and April 2015, using the Ooty radio telescope (ORT), located in Muthorai, India. This 530-meter-long and 30-meter-wide cylindrical paraboloid telescope allowed the researchers to observe the pulsar at 327 MHz, which resulted in detection of a faint periodic radio signal.”We report an extensive follow-up of the pulsar at 327 MHz with the Ooty radio telescope. Using the previously observed radio characteristics, and with an effective integration time of 60 hours, we present a detection of the pulsar at a confidence level of 99.82 percent,” the authors of the study wrote in the paper.The astronomers estimate that the 327 MHz mean flux density of J1732−3131 is between 0.5 and 0.8 mJy and the spectral index in the range from −2.4 to −3.0.More importantly, however, the 1,400 MHz pseudo-luminosity of the pulsar is only between 2.2 and 8.9 μJy kpc2, which suggests that J1732−3131 is one of the least luminous pulsars known to date.According to the scientists, their research provides new clues about gamma-ray pulsars in general, which could improve their understanding of these peculiar neutron stars. They noted that some of the radio-quiet gamma-ray pulsars might actually be very faint radio sources, and therefore not detectable in the radio searches using current generation telescopes. That is why the researchers call for more studies of such pulsars using more powerful radio telescopes.”The high sensitivity of upcoming radio telescopes like square kilometre array (SKA) and the 500-meter Aperture Spherical Telescope (FAST) will enable radio detection, and facilitate better studies of such pulsars,” the paper reads.SKA is a large, multi-radio telescope network being built in Australia and South Africa, which is expected to start initial observations in 2020. FAST is the world’s largest filled-aperture radio telescope, located in China. It achieved first light in September 2016, and is currently undergoing testing and commissioning. Explore further (Phys.org)—A team of astronomers led by Yogesh Maan of the Netherlands Institute for Radio Astronomy (ASTRON) has discovered radio emission from the gamma-ray pulsar known as J1732−3131. The study, presented in a paper published June 26 on arXiv.org, provides more details about J1732−3131, which was originally detected as a radio-quiet pulsar. Phase-aligned radio and gamma-ray profiles of J1732−3131. The continuous blue line shows the 327 MHz average profile from 2014 observations and the dashed-dotted-dashed red curve shows the gamma-ray profile. The horizontal extent of the grey shade on either side of the radio profile indicates the uncertainty in phase corresponding to 1σ error in DM. For clarity, both the profiles are duplicated and plotted over a range spanning two rotations of the pulsar. Credit: Maan et al., 2017. More information: Detection of radio emission from the gamma-ray pulsar J1732-3131 at 327 MHz, arXiv:1706.08613 [astro-ph.HE] arxiv.org/abs/1706.08613AbstractAlthough originally discovered as a radio-quiet gamma-ray pulsar, J1732-3131 has exhibited intriguing detections at decameter wavelengths. We report an extensive follow-up of the pulsar at 327 MHz with the Ooty radio telescope. Using the previously observed radio characteristics, and with an effective integration time of 60 hrs, we present a detection of the pulsar at a confidence level of 99.82%. The 327 MHz mean flux density is estimated to be 0.5-0.8 mJy, which establishes the pulsar to be a steep spectrum source and one of the least-luminous pulsars known to date. We also phase-aligned the radio and gamma-ray profiles of the pulsar, and measured the phase-offset between the main peaks in the two profiles to be 0.24±0.06. We discuss the observed phase-offset in the context of various trends exhibited by the radio-loud gamma-ray pulsar population, and suggest that the gamma-ray emission from J1732-3131 is best explained by outer magnetosphere models. Details of our analysis leading to the pulsar detection, and measurements of various parameters and their implications relevant to the pulsar’s emission mechanism are presented.
European eel. Credit: Wikipedia/CC BY-SA 3.0 A team of researchers with members from Japan, Sweden, Denmark and Germany has found evidence showing that European eel spawn across a 2000 km wide region of the North Atlantic Ocean. In their paper published in the journal Biology Letters, the group describes their study of recently hatched eel larvae in the North Atlantic Ocean, and what they found. Study shows European eel migration not as uniform and simple as thought More information: Michael J. Miller et al. Spawning by the European eel across 2000 km of the Sargasso Sea, Biology Letters (2019). DOI: 10.1098/rsbl.2018.0835 © 2019 Science X Network Explore further Journal information: Biology Letters Almost a hundred years ago, scientists discovered that European eels have a unique lifestyle—one that includes spawning in the Sargasso Sea, which is approximately 5000 to 7000 kilometers from where they live as juveniles and adults in European and North African rivers. But the extent of their spawning has never been pinned down. The researchers note also that the number of European eels has been dropping dramatically since the 1970s, and nobody knows why. The current population is believed to be approximately 5 percent of what it once was. In this new effort, the researchers used multiple ships to survey large parts of the North Atlantic Ocean from approximately 70°W to 50°W—to learn more about the spawning habits of the endangered eel.The Sargasso Sea is actually an area entirely within the North Atlantic Ocean, just off the east coast of the United States—it is the only sea in the world that has no land boundaries. It became singled out as voyagers discovered it was bounded by four ocean currents that form a gyre. It was named for the Sargassum seaweed that grows in abundance there. Prior research has shown the area to be mostly free of geographical formations—its bottom is mostly flat. The area is known for its marine plants and for its deep blue hue.The researchers report that their survey efforts showed recently hatched eel larvae floating across a 2000 km-wide region of the North Atlantic Ocean—not just the Sargasso Sea. They noted also that prior researchers working as far back as 1921 had found the larvae in similar parts of the ocean. The researchers suggest that despite severe reductions in population, the European eel still spawns as far and wide as it ever did. They suggest also that their findings may contribute to a plan for preventing the eels from disappearing altogether. Citation: European eel found to spawn across 2000 km wide region of the North Atlantic Ocean (2019, April 30) retrieved 18 August 2019 from https://phys.org/news/2019-04-european-eel-spawn-km-wide.html This document is subject to copyright. Apart from any fair dealing for the purpose of private study or research, no part may be reproduced without the written permission. The content is provided for information purposes only.
Citation: Fermi observations provide insights into the nature of Terzan 5 globular cluster (2019, June 3) retrieved 18 August 2019 from https://phys.org/news/2019-06-fermi-insights-nature-terzan-globular.html Three new millisecond pulsars discovered in Terzan 5 globular cluster Observations of globular clusters (GCs) in our Milky Way galaxy are of high importance for astronomers as they are among the oldest objects in the universe. Therefore, they could serve as natural laboratories for the study of stellar evolution processes.Discovered about a half-century ago, Terzan 5 is a 12-billion-year-old galactic GC located some 19,000 light years away. The cluster has a particularly high central stellar density, high metallicity, and also the highest stellar interaction rate of all GCs in the Milky Way. Terzan 5 is known to host 37 out of 130 millisecond pulsars (MSPs) detected so far, what makes it a record holder when it comes to the largest number of MSPs in a galactic GC. Previous studies of this cluster have also shown that it contains at least two distinct stellar populations with different ages and iron content. This could suggest that Terzan 5 may not be a “true” globular cluster, but a result of a merger of two clusters, for instance, or a remnant of a disrupted galaxy.In order to get more detailed information about Terzan 5, which could verify these possibilities, an international team of astronomers led by Hambeleleni Ndiyavala of North-West University in Potchefstroom, South Africa, decided to analyze new data obtained by the Fermi spacecraft. This dataset allowed the researchers to model the broadband spectral energy distribution (SED) in the cluster.”We therefore aimed to gather more data on Terzan 5 and model the updated SED in a leptonic scenario,” the astronomers wrote in the paper.In particular, the spectral model described in the study postulates four spectral components, namely: low-energy synchrotron radiation (LESR), high-energy synchrotron radiation (HESR), curvature radiation (CR) and inverse Compton (IC). The model also allowed the astronomers to constrain the MSP population’s distribution of spin-down luminosity.According to the study, the updated SED in Terzan 5 is most likely due to a cumulative pulsed emission from a population of embedded MSPs. Moreover, it could be as well attributed to unpulsed emission from the interaction of leptonic winds with ambient magnetic and soft-photon fields.”We obtained new Fermi data that we could fit using a model for the cumulative CR from a population of MSPs embedded within Terzan 5. These data also proved to be constraining for the low-energy tail of the unpulsed IC component, yielding a particle efficiency of ηp~3 percent, depending on the choice of several parameters, notably〈 ̇Evis〉and NMSP,tot,” the paper reads.In concluding remarks, the astronomers underlined the importance of further studies of Terzan 5 and similar clusters to get a more comprehensive view on the nature and properties of galactic GCs in general. They added that such instruments like the Cherenkov Telescope Array (CTA) could be much helpful in identifying new very-high-energy (VHE) GCs.”This will allow us to further scrutinize competing emission models, as well as developing new, more complete and comprehensive ones that might explain the spatial and spectral properties of galactic GCs at an ever increasing level of detail,” the authors of the paper noted. This document is subject to copyright. Apart from any fair dealing for the purpose of private study or research, no part may be reproduced without the written permission. The content is provided for information purposes only. © 2019 Science X Network More information: Hambeleleni Ndiyavala, et al. Probing the pulsar population of Terzan 5 via spectral modeling. arXiv:1905.10229v1 [astro-ph.HE]: arxiv.org/abs/1905.10229 Using NASA’s Fermi Gamma-ray Space Telescope, astronomers have collected important data that could disclose the real nature of the globular cluster Terzan 5. The new study, presented in a paper published May 24 on arXiv.org, delivers new information regarding the cluster’s pulsar population and its broadband emission spectrum. Explore further Different spectral components for Terzan 5 predicted by the leptonic models of Kopp et al. (2013) and Harding et al. (2008); Harding & Kalapotharakos (2015). Image credit: Ndiyavala et al., 2019.
However, with time his art became more restrictive and nuanced. Following that, his pictorial space became vacant and less detailed where figures were reduced to their bare structural essentials.In his on-going exhibition Building dreams from very little…, compositions of lithographs, watercolours and drawings, have certain reiterative images like a ball of thread symbolising the thread of human destiny; a rib-cage visible through the parched paper-thin skin. Hore’s deftly delineated figures serve as negative manifestations of community, ideology and a nation undergoing cataclysmic changes. Hore’s body of work is a facsimile impression of the unending poverty and violence in the world. ‘My paintings are personal, a response, almost a conversation, with my surroundings,’ said Hore.When: Till 20 DecemberWhere: Art Heritage Gallery