Tagged: National Astronomical Observatories of China (CN) at CAS Toggle Comment Threads | Keyboard Shortcuts

  • richardmitnick 11:34 am on November 30, 2020 Permalink | Reply
    Tags: "LAMOST-Kepler/K2 Survey Announces the First Light Result", , , , , Kepler photometry, LAMOST-Kepler project, National Astronomical Observatories of China (CN) at CAS, , ,   

    From National Astronomical Observatories of China (CN) and phys.org: “LAMOST-Kepler/K2 Survey Announces the First Light Result” 

    From National Astronomical Observatories of China (CN)

    at

    Chinese Academy of Sciences (CN)

    and


    From phys.org

    An international team led by Prof. Jian-Ning Fu and Dr. Weikai Zong, from Beijing Normal University, published the first light result of medium-resolution spectroscopic observations, which is undertaken by the LAMOST-Kepler/K2 Survey.

    4
    Phase II of the LAMOST-Kepler/K2 Survey.

    This result demonstrates that the medium-resolution spectrographs, equipped on LAMOST, perform to the designed expectation. The article is published this November online in the Astrophysical Journal Supplement Series.

    NASA/Kepler Telescope, and K2 March 7, 2009 until November 15, 2018.

    The LAMOST-Kepler/K2 Survey [science paper above] was launched based on the success of the LAMOST-Kepler project [RAA], a low-resolution spectroscopic survey that consecutive performed since 2011.

    1
    From LAMOST-Kepler project. Targets of scientific interest in the field of view (FOV) of the Keplermission. The black dots refer to the centers of the 14 LK-fields that cover the KeplerFOV. The following color coding is used: green for standard targets, blue for KASC targets, and orange for planet targets. The LK-fields observed in 2011–2014 are indicated by the circles drawn with a full line going from thick to thin and from gray to black, respectively.

    Different from LAMOST-Kepler project, the LAMOST-Kepler/K2 Survey aims to collect time-series spectroscopies with medium-resolution on about 55,000 stars distributed on Kepler and K2 campaigns, with higher priority given to the targets with available Kepler photometry. Each of those input targets will be visited about 60 times during the period from September 2018 to June 2023. This project is allocated with one sixth of the entire time within the LAMOST medium-resolution observations.

    From May 2018 to June 2019, a total of thirteen LAMOST-Kepler/K2 Survey footprints have been visited by LAMOST, and obtained about 370,000 high-quality spectra of 28,000 stars. The internal uncertainties for the effective temperature, surface gravity, metallicity and radial velocity are 80 K,0.08 dex, 0.05 dex and 1km/s when the signal to noise ratio equals to 20, respectively, which suggests that the performance of LAMOST medium-resolution spectrographs meet the designed expectation. The external comparisons with GAIA and APOGEE show that LAMOST stellar atmospheric parameters have a good linear relationship, which indicates the quality of LAMOST medium-resolution spectra is reliable.

    The result demonstrated that the medium-resolution spectrographs on LAMOST performed to the designed expectation.

    The LAMOST-Kepler/K2 Survey was launched based on the success of the LAMOST-Kepler project, a low-resolution spectroscopic survey that consecutively performed since 2011.

    Different from LAMOST-Kepler project, the LAMOST-Kepler/K2 Survey aims to collect time-series spectroscopies with medium resolution on about 55,000 stars distributed on Kepler and K2 campaigns, with higher priority given to the targets with available Kepler photometry.

    Each of those input targets will be visited about 60 times during the period from September 2018 to June 2023. This project is allocated with one-sixth of the entire time within the LAMOST medium-resolution observations.

    From May 2018 to June 2019, a total of 13 LAMOST-Kepler/K2 Survey footprints have been visited by LAMOST, and obtained about 370,000 high-quality spectra of 28,000 stars.

    The internal uncertainties for the effective temperature, surface gravity, metallicity and radial velocity were 80 K,0.08 dex, 0.05 dex and 1km/s when the signal to noise ratio equals to 20, respectively, which suggested that the performance of LAMOST medium-resolution spectrographs meet the designed expectation.

    The external comparisons with GAIA and APOGEE showed that LAMOST stellar atmospheric parameters had a good linear relationship, which indicated the quality of LAMOST medium-resolution spectra is reliable.

    ESA (EU)/GAIA satellite .

    SDSS Apache Point Observatory Galactic Evolution Experiment – Apogee

    SDSS Telescope at Apache Point Observatory, near Sunspot NM, USA, Altitude2,788 meters (9,147 ft).

    Apache Point Observatory, near Sunspot, New Mexico Altitude 2,788 meters (9,147 ft).

    The LAMOST-Kepler/K2 Survey is the first project dedicated to obtaining time series of spectra by using the LAMOST medium-resolution spectrographs, pointing toward the Kepler/K2 fields. These spectra will be very important for many scientific goals, including the discovery of new binaries or even the brown dwarfs, the study of oscillation dynamics for large-amplitude pulsators and the investigation of the variability of stellar activity.

    See the full article here .

    five-ways-keep-your-child-safe-school-shootings

    Please help promote STEM in your local schools.

    Stem Education Coalition

    The National Astronomical Observatories of the Chinese Academy of Sciences (NAOC) (CN) was officially founded in April 2001 through the merger of four observatories, three observing stations and one research center, all under the Chinese Academy of Sciences (CAS).

    NAOC is headquartered in Beijing and has four subordinate units across the country: the Yunnan Observatory (YNAO), the Nanjing Institute of Astronomical Optics and Technology (NIAOT), the Xinjiang Astronomical Observatory (XAO) and the Changchun Observatory.

    The headquarters of NAOC, located in Beijing and formerly known as the Beijing Astronomical Observatory, is simply referred to as NAOC. Established in 1958 and aiming at the forefront of astronomical science, NAOC conducts cutting-edge astronomical studies, operates major national facilities and develops state-of the-art technological innovations. Applying astronomical methods and knowledge to fulfill national interests and needs is also an integral part of the mission of NAOC. NAOC hosts the Center for Astronomical Mega-Science of Chinese Academy of Sciences (CAMS), which is a new initiative to establish a mechanism for reaching consensus in the construction of major facilities, operations and technology developments among the CAS core observatories (NAOC; the Purple Mountain Observatory, PMO; and the Shanghai Astronomical Observatory, SHAO). CAMS will strive for the sharing of financial, personnel resources and technical expertise among the three core observatories of CAS.

    NAOC’s main research involves cosmological large-scale structures, the formation and evolution of galaxies and stars, high-energy astrophysics, solar magnetism and activity, lunar and deep space exploration, and astronomical instrumentation.

    NAOC has seven major research divisions in the areas of optical astronomy, radio astronomy, galaxies and cosmology, space science, solar physics, lunar and deep space exploration, and applications in astronomy. These divisions encompass more than 50 research groups and house the CAS Key Laboratories of Optical Astronomy, Solar Activity, Lunar and Deep-Space Exploration, Space Astronomical Science and Technology, and Computational Astrophysics.

    NAOC also has three major observing stations: Xinglong, for optical and infrared astronomy; Huairou, for solar magnetics; and Miyun, for radio astronomy and satellite data downlinks. NAOC has been deeply involved in the China Lunar Exploration Program, from designing and managing lunar exploration satellite payload systems, to receiving, storing and analyzing the data transmitted by these satellites from space. NAOC also has a GPU super-cluster computing facility with 85 nodes at a peak performance of up to 280 teraflops.

    NAOC also publishes Research in Astronomy and Astrophysics (RAA), a journal catalogued by SCI.

    The Chinese Academy of Sciences (CN) is the linchpin of China’s drive to explore and harness high technology and the natural sciences for the benefit of China and the world. Comprising a comprehensive research and development network, a merit-based learned society and a system of higher education, CAS brings together scientists and engineers from China and around the world to address both theoretical and applied problems using world-class scientific and management approaches.

    Since its founding, CAS has fulfilled multiple roles — as a national team and a locomotive driving national technological innovation, a pioneer in supporting nationwide S&T development, a think tank delivering S&T advice and a community for training young S&T talent.

    Now, as it responds to a nationwide call to put innovation at the heart of China’s development, CAS has further defined its development strategy by emphasizing greater reliance on democratic management, openness and talent in the promotion of innovative research. With the adoption of its Innovation 2020 programme in 2011, the academy has committed to delivering breakthrough science and technology, higher caliber talent and superior scientific advice. As part of the programme, CAS has also requested that each of its institutes define its “strategic niche” — based on an overall analysis of the scientific progress and trends in their own fields both in China and abroad — in order to deploy resources more efficiently and innovate more collectively.

    As it builds on its proud record, CAS aims for a bright future as one of the world’s top S&T research and development organizations.

     
  • richardmitnick 10:19 am on October 22, 2020 Permalink | Reply
    Tags: "The First Star in Our Galaxy Caught Sending Out Fast Radio Bursts Is Doing It Again", , , , , , Magnetar SGR 1935+2154, National Astronomical Observatories of China (CN) at CAS, , ,   

    From Science Alert: “The First Star in Our Galaxy Caught Sending Out Fast Radio Bursts Is Doing It Again” 

    ScienceAlert

    From Science Alert (AU)

    22 OCTOBER 2020
    MICHELLE STARR

    1
    Artist’s impression of a magnetar. Credit: Sophia Dagnello, NRAO/AUI/NSF.

    A little dead star that dazzled us earlier this year is not done with its shenanigans.

    Magnetar SGR 1935+2154, which in April emitted the first known fast radio burst from inside the Milky Way, has flared up once more, giving astronomers yet another chance to solve more than one major cosmic mystery.

    On 8 October 2020, the CHIME/FRB collaboration detected SGR 1935+2154 emitting three millisecond radio bursts in three seconds.

    CHIME Canadian Hydrogen Intensity Mapping Experiment -A partnership between the University of British Columbia (CA), the University of Toronto (CA), McGill University (CA), Yale and the National Research Council in British Columbia (CA), at the Dominion Radio Astrophysical Observatory in Penticton, British Columbia, CA Altitude 545 m (1,788 ft).

    Following up on the CHIME/FRB detection, the FAST radio telescope found something else – a pulsed radio emission consistent with the magnetar’s spin period.

    “It’s really exciting to see SGR 1935+2154 back again, and I’m optimistic that as we study these bursts more carefully, it will help us better understand the potential relationship between magnetars and fast radio bursts,” astronomer Deborah Good of the University of British Columbia in Canada, and member of the CHIME/FRB, told ScienceAlert.

    The detections, reported in The Astronomer’s Telegram, are currently undergoing analysis.

    Before April of this year, fast radio bursts (FRBs) had only ever been detected coming from outside the galaxy, usually from sources millions of light-years away. The first one was discovered in 2007, and ever since, astronomers have been trying to figure out what causes them.

    As the name implies, FRBs are bursts of extremely powerful radio waves detected in the sky, some discharging more energy than hundreds of millions of Suns. They last mere milliseconds.

    Because most fast radio burst sources seem to flare once and haven’t been detected repeating, they’re extremely unpredictable. In addition, the ones we’ve detected usually come from so far away, our telescopes are unable to pick out individual stars. Both of these characteristics make FRBs challenging to track down either to an exact source galaxy, or a known cause.

    But SGR 1935+2154 is only around 30,000 light-years away. On 28 April 2020, it spat out a powerful millisecond-duration burst, which has since been named FRB 200428 in keeping with fast radio burst naming conventions.

    Once the power of the signal was corrected for distance, FRB 200428 was found to be not quite as powerful as extragalactic fast radio bursts – but everything else about it fit the profile.

    “If the same signal came from a nearby galaxy, like one of the nearby typical FRB galaxies, it would look like an FRB to us,” astronomer Shrinivas Kulkarni of Caltech told ScienceAlert in May. “Something like this has never been seen before.”

    We don’t know much about the three new bursts yet. Because scientists are still working on the data, it’s possible that some early conclusions are likely to change, Good told ScienceAlert. But we can already tell that they are both like and unlike FRB 200428.

    They are a little less powerful again, but they are all still incredibly strong, and all just milliseconds long. “Although less bright than the detection earlier this year, these are still very bright bursts which we’d see if they were extragalactic,” Good said.

    “One of the most interesting aspects of this detection is that our three bursts seem to have occurred within one rotation period. The magnetar is known to rotate once every ~3.24 seconds, but our first and second bursts were separated by 0.954 seconds, and the second and third were separated by 1.949 seconds. That’s a bit unusual, and I think it’s something that we’ll be looking into further going forward.”

    That could reveal something new and useful about magnetar behaviour, because – let’s face it – they are pretty weird.

    Magnetars – of which we have only confirmed 24 to date – are a type of neutron star; that’s the collapsed core of a dead star not massive enough to turn into a black hole. Neutron stars are small and dense, about 20 kilometres (12 miles) in diameter, with a maximum mass of about two Suns. But magnetars add something else to the mix: a shockingly powerful magnetic field.

    These jaw-dropping fields are around a quadrillion times more powerful than Earth’s magnetic field, and a thousand times more powerful than that of a normal neutron star. And we still don’t fully understand how they got that way.

    But we do know that magnetars undergo periods of activity. As gravity tries to keep the star together – an inward force – the magnetic field, pulling outward, is so powerful, it distorts the star’s shape. This leads to ongoing tension which occasionally produces gargantuan starquakes and giant magnetar flares.

    SGR 1935+2154 has been undergoing such activity, suggesting a link between magnetar tantrums and at least some FRBs.

    Obviously, astronomers have found the source of the first intra-galactic FRB to be of intense interest. When CHIME/FRB reported their detection, other astronomers went to have a look at the star, including a team led by Zhu Weiwei of the National Astronomical Observatories of China who had access to FAST, the largest single-aperture radio telescope in the world.

    FAST [Five-hundred-meter Aperture Spherical Telescope] radio telescope, with phased arrays from CSIRO engineers Australia located in the Dawodang depression in Pingtang County, Guizhou Province, South China.

    And they found something interesting, also reported in The Astronomer’s Telegram – pulsed radio emission. These radio pulses were nowhere near as strong as the bursts, but they’re extremely rare: If validated, SGR 1935+2154 will only be the sixth magnetar with pulsed radio emission. And the pulse period was found to be 3.24781 seconds – almost exactly the star’s spin period.

    This is curious, because so far, astronomers have struggled to find a link between magnetars and radio pulsars. Pulsars are another type of neutron star; they have a more normal magnetic field, but they pulse in radio waves as they spin, and astronomers have long tried to figure out how the two types of stars are related.

    Earlier this year, Australian astronomers identified a magnetar that was behaving like a radio pulsar – a possible “missing link” between the two, and evidence that at least some magnetars could evolve into pulsars. SGR 1935+2154 could be another piece of the puzzle.

    “Based on these results and the increasing bursting activities, we speculate that the magnetar may be in the process of turning into an active radio pulsar,” Weiwei’s team wrote.

    What an absolutely bloody fascinating little star this is turning out to be.

    See the full article here .

    five-ways-keep-your-child-safe-school-shootings

    Please help promote STEM in your local schools.

    Stem Education Coalition

     
c
Compose new post
j
Next post/Next comment
k
Previous post/Previous comment
r
Reply
e
Edit
o
Show/Hide comments
t
Go to top
l
Go to login
h
Show/Hide help
shift + esc
Cancel
%d bloggers like this: