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  • richardmitnick 8:35 am on October 22, 2021 Permalink | Reply
    Tags: "LAMOST Helps Detect Dust in the Outskirts of Andromeda Galaxy and Triangulum Galaxy", Andromeda Galaxy (Messier 31) and Triangulum Galaxy (Messier 33), , , , , Xinglong Observatory [兴隆观测站] (CN)   

    From Xinglong Observatory [兴隆观测站] (CN): “LAMOST Helps Detect Dust in the Outskirts of Andromeda Galaxy and Triangulum Galaxy” 

    LAMOST telescope located in Xinglong Station, Hebei Province, China, Altitude 960 m (3,150 ft).

    From Xinglong Observatory [兴隆观测站] (CN)

    Chinese Academy of Sciences [中国科学院] (CN)

    Mar 18, 2021

    XU Ang
    The National Astronomical Observatories of China [ 国家天文台] at Chinese Academy of Sciences [中国科学院](CN)
    annxu@nao.cas.cn

    Dust as an annoying thing is quite common in our everyday lives. But the ubiquitous dust in the vast universe is a subject of great interest to astronomers.

    A recent work led by Doctoral Candidate ZHANG Ruoyi and Prof. YUAN Haibo from the Department of Astronomy, Beijing Normal University [北京師範大學](CN), reports the detection of dust in the outskirts of Andromeda Galaxy (Messier 31) and Triangulum Galaxy (Messier 33).

    Andromeda Galaxy Messier 31 with Messier 32 -a satellite galaxy Credit:Terry Hancock- Down Under Observatory (US).

    The Triangulum Galaxy, Messier 33, via The VLT Survey Telescope (VST) at ESO’s Paranal Observatory in Chile. This beautifully detailed image of the galaxy Messier 33. This nearby spiral, the second closest large galaxy to our own galaxy, the Milky Way, is packed with bright star clusters, and clouds of gas and dust. This picture is amongst the most detailed wide-field views of this object ever taken and shows the many glowing red gas clouds in the spiral arms with particular clarity.

    Part of ESO’s Paranal Observatory the VLT Survey Telescope (VISTA) observes the brilliantly clear skies above the Atacama Desert of Chile. It is the largest survey telescope in the world in visible light, with an elevation of 2,635 metres (8,645 ft) above sea level.

    The results were published in The Astrophysical Journal Letters.

    Messier 31 and Messier 33 are the largest and 3rd largest galaxies in the Local Group, respectively.

    Local Group. Andrew Z. Colvin 3 March 2011

    It is extremely challenging to detect dust in the outskirts of Messier 31 and Messier 33, as their signals are very weak, in terms of either dust absorption in optical and/or emission in far infrared, compared to those of dust in the Milky Way. Therefore, the signals from Galactic foreground dust have to be removed carefully.

    Fortunately, thanks to the Large Sky Area Multi-Object Fiber Spectroscopic Telescope (LAMOST), also known as Guoshoujing Telescope, operated by The National Astronomical Observatories of China [ 国家天文台] at Chinese Academy of Sciences [中国科学院](CN), millions of high-quality spectra have been recorded, providing a great opportunity to map the dust distribution in the Milky Way.

    Using a sample of about 190,000 stars from the LAMOST and Gaia, the researchers constructed a large and precise two-dimensional foreground dust reddening map toward the M31 and M33 region.

    “This foreground dust reddening map tells people how much light is absorbed by dust in the Milky Way,” said ZHANG Ruoyi, the leading author of this study. The map shows the complex structure of dust clouds toward the Messier 31, suggesting that the map should be used for precise foreground reddening corrections for targets in Messier 31.

    By carefully removing the foreground reddening from the SFD98 dust reddening map, which contains dust signals from all the Milky Way, Messier 31 and Messier 33, the distribution of dust in the outskirts of Messier 31 and Messier 33 are revealed in great detail to a very large distance. Dust in the Messier 31 and Messier 33 disks extends out to about 2.5 times their optical radii.

    The researchers also found that a significant amount of dust in clumpy and filamentary structures exists in the halo of Messier 31, out to a distance of over 100 kiloparsec (1 kiloparsec equals to 3260 light years), which is about 5 times its optical radius.

    Where do the dust clouds in the halo come from? Are their properties similar to those in the disk? There are interesting questions to be answered. “Our results combined with future observations, e.g., observations by FAST, will provide new clues on the distributions, properties, and cycling of dust in spiral galaxies,” said Prof. YUAN Haibo, the corresponding author.

    2
    Figure: Left: Foreground reddening map of LAMOST. The solid ellipses mark the optical extent of Messier 31, Messier 33, and two satellites Messier 32 and Messier 101. Right: Dust reddening map of Messier 31 and Messier 33. The two dotted ellipses centered on Messier 31 and Messier 33 represent the extent of their dust disks. The large circle centered on Messier 31 represents the extent of its dust halo. Image by ZHANG Ruoyi.

    See the full article here .

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

    Please help promote STEM in your local schools.

    Stem Education Coalition

    Chinese Academy of Sciences-National Astronomical Observatories Xinglong Observatory Station, located in Xinglong Station, Hebei Province, China.

    The Xinglong Observatory [兴隆观测站] (CN) of the National Astronomical Observatories, Chinese Academy of Sciences (NAOC) (IAU code: 327, coordinates: 40°23′39′′ N, 117°34′30′′ E) was founded in 1968. At present, it is one of most primary observing stations of NAOC. As the largest optical astronomical observatory site in the continent of Asia, it has 9 telescopes with effective aperture larger than 50 cm. These are the Guo Shoujing Telescope, also called the Large Sky Area Multi-Object Fiber Spectroscopic Telescope (LAMOST), the 2.16-m Telescope, a 1.26-m optical & near-infrared telescope, a 1-m Alt-Az telescope, an 85-cm telescope (NAOC-Beijing Normal University [北京師範大學](CN) Telescope, NBT), an 80-cm telescope (Tsinghua University [清华大学](CN)-NAOC Telescope, TNT), a 60-cm telescope, a 50-cm telescope and a 60/90-cm Schmidt telescope.
    The average altitude of the Xinglong Observatory is about 900 m. The Xinglong Observatory is located at the south of the main peak of the Yanshan Mountains, in the Xinglong County, Hebei Province, which lies about 120 km (about 2 hours’ drive) to the northeast of Beijing. A shuttle bus runs between NAOC campus and Xinglong Observatory every Tuesday and Friday. The mean and media seeing values of the Xinglong Observatory are 1.9′′ and 1.7′′, respectively. On average, there are 117 photometric nights and 230 observable nights per year based on the data of 2007-2014. Most of the time, the wind speed is less than 4 m/s (the mean value is 2 m/s), and the sky brightness is about 21.1 mag arcsec2 in V band at the zenith.

    Each year, more than a hundred astronomers use the telescopes of the Xinglong Observatory to perform the observations for the studies on Galactic sciences (stellar parameters, extinction measurements, Galactic structures, exoplanets, etc.) and extragalactic sciences (including nearby galaxies, AGNs, high-redshift quasars), as well as time-domain astronomy (supernovae, gamma-ray bursts, stellar tidal disruption events, and different types of variable stars). In recent years, besides the basic daily maintenance of the telescopes, new techniques and methods have been explored by the engineers and technicians of the Xinglong Observatory to improve the efficiency of observations. Meanwhile, the Xinglong Observatory is also a National populscience and education base of China for training students from graduate schools, colleges, high schools and other education institutes throughout China, and it has hosted a number of international workshops and summer schools.

    The Chinese Academy of Sciences [中国科学院] (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 9:13 pm on October 11, 2021 Permalink | Reply
    Tags: "Nature of unknown gamma-ray sources revealed", , , , , Gamma-ray Astronomy, , , , , Xinglong Observatory [兴隆观测站] (CN)   

    From Xinglong Observatory [兴隆观测站] (CN) via phys.org : “Nature of unknown gamma-ray sources revealed” 

    LAMOST telescope located in Xinglong Station, Hebei Province, China, Altitude 960 m (3,150 ft).

    From Xinglong Observatory [兴隆观测站] (CN)

    Chinese Academy of Sciences [中国科学院] (CN)

    via

    phys.org

    October 11, 2021
    Li Yuan, Chinese Academy of Sciences [中国科学院] (CN)

    1
    Fig. 1 Artistic representation of an active galaxy jet. Credit: M. Kornmesser/European Southern Observatory [Observatoire européen austral][Europäische Südsternwarte](EU)(CL).

    An international team of astronomers has unveiled the nature of hundreds of gamma-ray emitting sources, discovering that most of them belong to the class of active galaxies known as blazars.

    Their recent study was published in The Astronomical Journal.

    One of the most intriguing challenges in modern gamma-ray astronomy is searching for low-energy counterparts of unidentified gamma-ray sources. Unidentified sources constitute about 1/3 of all celestial objects detected by the Fermi satellite to date, the most recent gamma-ray mission with unprecedented capabilities for observing the high energy sky.

    Since the largest population of known gamma-ray sources are blazars, astronomers believe they can also classify most unidentified gamma-ray sources as blazars. However, they can completely understand their nature only by observing blazar candidates at visible frequencies.

    Blazars are extremely rare, black hole-powered galaxies. They host a supermassive black hole in their central regions that sweep out matter at almost the speed of light in the form of a powerful jet pointing towards the Earth. Particles accelerated in these jets can emit light up to the most energetic gamma-rays, thus being visible by instruments onboard the Fermi satellite.

    2
    Fig. 2 Example of the completely featureless optical spectrum of the BL Lac known as J065046.49+250259.6. Credit: Harold A. Peña Herazo.

    The team, led by Dr. Harold Peña Herazo from The National Institute for Astrophysics, Optics and Electronics(MX), analyzed hundreds of optical spectra collected by the Large Sky Area Multi-Object Fabre Spectroscopic Telescope (LAMOST) at the Xinglong Station in China [above].

    LAMOST is hosted by The National Astronomical Observatories of China [ 国家天文台] at Chinese Academy of Sciences [中国科学院](CN). It provided a unique opportunity to unveil the nature of blazar-like sources that can potentially be counterparts of unidentified gamma-ray sources.

    From the list of sources discovered by the Fermi satellite, the researchers selected a sample of Blazar Candidates of Uncertain type (BCUs), which share several properties in common with blazars. However, optical spectroscopic observations are necessary to determine their proper classification and confirm their nature.

    Using spectroscopic data available in the LAMOST archive, the researchers were able to classify tens of BCUs as blazars. “LAMOST data also permitted verifying the nature of hundreds of additional blazars by searching for emission or absorption lines used to determine their cosmological distances,” said Prof. GU Minfeng from The Shanghai Astronomical Observatory [上海天文台]Chinese Academy of Sciences [上海天文台](CN).

    The vast majority of sources belong to the blazar class known as BL Lac objects and have a completely featureless optical spectrum. This makes measuring their cosmological distances an extremely challenging task. However, thanks to the LAMOST observations, a few more of them have luckily revealed visible signatures in their optical spectra.

    “Our analysis showed great potential for the LAMOST survey and allowed us to discover a few changing-look blazars,” said Dr. Peña Herazo, currently a postdoctoral fellow at The East Asian Observatory – Hilo, Hawaii(US).

    “It is worth noting that the possibility of using LAMOST observations to estimate blazar cosmological distances is critical to studying this population, its cosmological evolution, the imprint in the extragalactic gamma-ray background light in the gamma-ray spectra, and the blazar contribution to the extragalactic gamma-ray background,” said Prof. Francesco Massaro from the University of Turin.

    “I started working on this optical campaign and analyzing spectroscopic data in 2015, and nowadays, thanks to the observations available in LAMOST archive, we certainly made a significant step toward the identification of gamma-ray sources with blazars. Future perspectives achievable thanks to LAMOST datasets will definitively reveal the nature of hundreds of new blazars in the years to come,” commented Dr. Federica Ricci at The University of Bologna [Alma mater studiorum – Università di Bologna](IT) and INAF-Institute for Radio Astronomy of Bologna [Istituto di Radioastronomia di Bologna](IT).

    The group’s previous study was also published in The Astronomical Journal.

    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 Xinglong Observatory [兴隆观测站] (CN) of the National Astronomical Observatories, Chinese Academy of Sciences (NAOC) (IAU code: 327, coordinates: 40°23′39′′ N, 117°34′30′′ E) was founded in 1968. At present, it is one of most primary observing stations of NAOC. As the largest optical astronomical observatory site in the continent of Asia, it has 9 telescopes with effective aperture larger than 50 cm. These are the Guo Shoujing Telescope, also called the Large Sky Area Multi-Object Fiber Spectroscopic Telescope (LAMOST), the 2.16-m Telescope, a 1.26-m optical & near-infrared telescope, a 1-m Alt-Az telescope, an 85-cm telescope (NAOC-Beijing Normal University [北京師範大學](CN) Telescope, NBT), an 80-cm telescope (Tsinghua University [清华大学](CN)-NAOC Telescope, TNT), a 60-cm telescope, a 50-cm telescope and a 60/90-cm Schmidt telescope.

    The average altitude of the Xinglong Observatory is about 900 m. The Xinglong Observatory is located at the south of the main peak of the Yanshan Mountains, in the Xinglong County, Hebei Province, which lies about 120 km (about 2 hours’ drive) to the northeast of Beijing. A shuttle bus runs between NAOC campus and Xinglong Observatory every Tuesday and Friday. The mean and media seeing values of the Xinglong Observatory are 1.9′′ and 1.7′′, respectively. On average, there are 117 photometric nights and 230 observable nights per year based on the data of 2007-2014. Most of the time, the wind speed is less than 4 m/s (the mean value is 2 m/s), and the sky brightness is about 21.1 mag arcsec2 in V band at the zenith.

    Each year, more than a hundred astronomers use the telescopes of the Xinglong Observatory to perform the observations for the studies on Galactic sciences (stellar parameters, extinction measurements, Galactic structures, exoplanets, etc.) and extragalactic sciences (including nearby galaxies, AGNs, high-redshift quasars), as well as time-domain astronomy (supernovae, gamma-ray bursts, stellar tidal disruption events, and different types of variable stars). In recent years, besides the basic daily maintenance of the telescopes, new techniques and methods have been explored by the engineers and technicians of the Xinglong Observatory to improve the efficiency of observations. Meanwhile, the Xinglong Observatory is also a National populscience and education base of China for training students from graduate schools, colleges, high schools and other education institutes throughout China, and it has hosted a number of international workshops and summer schools.

    The Chinese Academy of Sciences [中国科学院] (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 9:57 pm on June 30, 2021 Permalink | Reply
    Tags: "A fast-expanding Type Ia supernova exploded in NGC 474 study finds", , , , , , , Xinglong Observatory [兴隆观测站] (CN)   

    From Xinglong Observatory [兴隆观测站] (CN) via phys.org : “A fast-expanding Type Ia supernova exploded in NGC 474, study finds” 

    LAMOST telescope located in Xinglong Station, Hebei Province, China.

    From Xinglong Observatory [兴隆观测站] (CN)

    Chinese Academy of Sciences [中国科学院] (CN)

    via

    phys.org

    June 30, 2021
    Tomasz Nowakowski

    1
    The left panel shows a color image which is synthesized from observations in gr bands obtained by the CFHT
    before the discovery of SN 2017fgc. The red circle marks the position of SN 2017fgc and the gas bridge can be clearly seen here. The right panel shows a color image synthesized from TNT observations in the gri bands after the explosion of SN 2017fgc, and the SN is marked with a red circle while the reference stars are labeled by numbers. Credit: Zeng et al., 2021.


    Using ground-based facilities, astronomers from China and elsewhere have conducted extensive optical photometric and spectroscopic observations of the supernova SN 2017fgc, which exploded in the galaxy NGC 474. Results of the study, published June 23, indicate that this explosion is a fast-expanding Type Ia supernova.

    Type Ia supernovae (SN Ia) are found in binary systems in which one of the stars is a white dwarf. Stellar explosions of this type are important for the scientific community, as they offer essential clues into the evolution of stars and galaxies.

    SN 2017fgc was detected on July 9, 2017 by the Distance Less Than 40 Mpc (DLT40) survey. Further studies of SN 2017fgc classified it as a normal supernova of Type Ia and found that it exploded in the nearby shell galaxy NGC 474 at a distance of some 96.2 million light years.

    Now, new observations of SN 2017fgc conducted by a team of astronomers led by Xiangyun Zeng of the Xinjiang Astronomical Observatory in China, shed more light on the properties of this SN. The team used a set of various observatories for their study, including the 0.8 m Tsinghua NAOC telescope (TNT).

    2
    Tsinghua NAOC telescope (TNT)

    The researchers monitored SN 2017fgc from 12 days before to around 389 days after its maximum brightness. The observations found that the SN has an absolute peak magnitude of about −19.32 mag and a post-peak decline at a level of 1.05 mag. Its peak luminosity was measured to be approximately 13.2 tredecillion erg/s, what indicates a synthesized nickel mass of about 0.51 solar masses.

    The spectral evolution of SN 2017fgc suggests that it is a high-velocity (HV) SN Ia. It was noted that it has a maximum-light Si II velocity of about 15,000 km/s and a post-peak velocity gradient at a level of some 120 km/s/d. Moreover, the light curve and color curve evolution of SN 2017fgc turned out to be similar to those of other fast-expanding HV SNe Ia such as SN 2002bo and SN 2006X.

    However, the study found that SN 2017fgc is located far away (about 61,600 light years) from the center of its host galaxy, while HV SNe Ia usually explode near the center of their hosts.

    “It seems that SN 2017fgc is an outlier and does not follow this trend of HV SNe Ia. However, closer inspection of the host galaxy NGC 474 reveals that it is a massive lenticular galaxy that experienced a merger ∼ 2 Gyr ago. (…) We speculate that SN 2017fgc could be ejected from the inner part of the companion galaxy NGC 470 during the merger that took place at ∼2 Gyr ago, or formed as a result of some cold gas remaining in the companion disk,” the astronomers write.

    They added that more observations, focused on the host environment of SN 2017fgc, are needed to confirm this assumption.

    See the full article here .

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

    Please help promote STEM in your local schools.

    Stem Education Coalition

    Chinese Academy of Sciences-National Astronomical Observatories Xinglong Observatory Station, located in Xinglong Station, Hebei Province, China.

    The Xinglong Observatory [兴隆观测站] (CN) of the National Astronomical Observatories, Chinese Academy of Sciences (NAOC) (IAU code: 327, coordinates: 40°23′39′′ N, 117°34′30′′ E) was founded in 1968. At present, it is one of most primary observing stations of NAOC. As the largest optical astronomical observatory site in the continent of Asia, it has 9 telescopes with effective aperture larger than 50 cm. These are the Guo Shoujing Telescope, also called the Large Sky Area Multi-Object Fiber Spectroscopic Telescope (LAMOST), the 2.16-m Telescope, a 1.26-m optical & near-infrared telescope, a 1-m Alt-Az telescope, an 85-cm telescope (NAOC-Beijing Normal University Telescope, NBT), an 80-cm telescope (Tsinghua University-NAOC Telescope, TNT), a 60-cm telescope, a 50-cm telescope and a 60/90-cm Schmidt telescope.

    The average altitude of the Xinglong Observatory is about 900 m. The Xinglong Observatory is located at the south of the main peak of the Yanshan Mountains, in the Xinglong County, Hebei Province, which lies about 120 km (about 2 hours’ drive) to the northeast of Beijing. A shuttle bus runs between NAOC campus and Xinglong Observatory every Tuesday and Friday. The mean and media seeing values of the Xinglong Observatory are 1.9′′ and 1.7′′, respectively. On average, there are 117 photometric nights and 230 observable nights per year based on the data of 2007-2014. Most of the time, the wind speed is less than 4 m/s (the mean value is 2 m/s), and the sky brightness is about 21.1 mag arcsec2 in V band at the zenith.

    Each year, more than a hundred astronomers use the telescopes of the Xinglong Observatory to perform the observations for the studies on Galactic sciences (stellar parameters, extinction measurements, Galactic structures, exoplanets, etc.) and extragalactic sciences (including nearby galaxies, AGNs, high-redshift quasars), as well as time-domain astronomy (supernovae, gamma-ray bursts, stellar tidal disruption events, and different types of variable stars). In recent years, besides the basic daily maintenance of the telescopes, new techniques and methods have been explored by the engineers and technicians of the Xinglong Observatory to improve the efficiency of observations. Meanwhile, the Xinglong Observatory is also a National populscience and education base of China for training students from graduate schools, colleges, high schools and other education institutes throughout China, and it has hosted a number of international workshops and summer schools.

    The Chinese Academy of Sciences [中国科学院] (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.

     
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