31 research outputs found
Прогнозирование содержания нерастворимого остатка в коржах рабочих пластов Верхнекамского месторождения солей
Using data from the exploration drilling at the mines BKPRU-2 and BKPRU-3 of JSC Uralkali, the relationship equations between the content of insoluble residue in the productive sylvinite beds and thick interbedded clay layers at their top referred to as «korjʼs» are worked out. Knowledge of composition and thickness of clay layers is very important for rockfall protection during mining work. The results of analysis of drilling data are often not reliable because of the losses of clay material in the extracted core. The resulting equations are recommended for forecastingof insoluble residue in «korjʼs» of those beds.Используя данные эксплуатационной разведки шахтных полей рудников БКПРУ-2 и БКПРУ-3 ПАО «Уралкалий», получены уравнения зависимости между содержанием нерастворимого остатка (Н.О.) в рабочих пластах сильвинитового состава (КрII и АБ) и их коржах, которые рекомендуются для прогнозирования
Attitude to the childfree phenomenon of modern youth: regional aspect
The article provides an overview of key theoretical approaches to the phenomenon of voluntary and deliberate childlessness, or childfree phenomenon, which are used in modern sociological and socio-psychological science against the background of transformation of family values and the institution of family. The authors highlighted some of the patterns of the phenomenon specific to modern society and presented the results of an empirical study carried out with participation of Perm youth. These results allow to identify regional aspects of the attitude towards the childfree phenomenon by means of analyzing a set of parameters: the ideas that young people have of the childfree phenomenon; their emotional assessment of the phenomenon; awareness of the childfree social movement’s activities in the Russian Federation; attitude towards representatives of the social movement; willingness to support the ideas of the movement’s representatives; as well as willingness to have or not to have children. The authors also analyzed the main factors that influence the formation of young people’s attitude towards the childfree phenomenon and the corresponding social movement
JVLA overview of the bursting HO maser source G25.65+1.05
The source G25.65+1.05 (RAFGL7009S, IRAS 18316-0602) is the least studied of
the three regions of massive star formation known to show exceptionally
powerful HO maser bursts. We report spectral line observations of the
HO maser at 22 GHz, the methanol maser transitions at 6.7, 12.2 and 44 GHz,
and the continuum in these same frequency bands with The Karl G. Jansky Very
Large Array (JVLA) at the post-burst epoch of 2017. For the first time, maps of
22 GHz HO and 44 GHz CHOH maser spots are obtained and the absolute
position of the 22 GHz HO bursting feature is determined with
milliarcsecond precision. We detected four continuum components, three of which
are closely spaced in a linear orientation, suggesting a physical link between
them
Online Database of Multiwavelength Water Masers in Galactic Star-Forming Regions
In this paper, we present an online multiwavelength database of water masers in star-forming regions of the Galaxy. The collected data represent 1/495% of all observations of water masers in star-forming regions published since 1989. Nineteen transitions are included, from 22 GHz to 1.88 THz. The MaserDB.net information system provides fast and open access to the collected data, including maser tabular data, spectra, and interferometric maser spot data. The database covers 1/418,700 individual observations and 1/47200 maser detections. The data on the water maser detection are available for 1/42600 sources, and interferometric data are available for 1/4560 sources. Statistical analysis of the water masers' data and comparison with other abundant maser species found in star-forming regions (OH and CH3OH of class I and II) show that water masers are the most ubiquitous maser type. Access to the water maser database is available online at https://MaserDB.net. The database can be queried using a web search form or Structured Query Language. © 2022. The Author(s). Published by the American Astronomical Society.The work on development of the water masers database and association with external catalogs (Section ), the web interface improve (Section ) and the analysis of the water masers’ distribution in the Galaxy (Section ) were funded by Russian Science Foundation grant 20-72-00137. The work on checking the quality of the source classification scheme (Section ) was supported by the Russian Ministry of Science and Higher Education, No. FEUZ-2020-0030. The work on the detection rate of water masers in star-forming regions (Section ) was funded by Russian Science Foundation grant 18-12-00193
The Effelsberg survey of FU~Orionis and EX~Lupi objects II. H2O maser observations
Funding: Zs.M.Sz. acknowledges funding from a St Leonards scholarship from the University of St Andrews. This project has received funding from the European Research Council (ERC) under the European Union’s Horizon 2020 research and innovation programme under grant agreement No 716155 (SACCRED).Context. FU Orionis (FUor) and EX Lupi (EXor) type objects are two groups of peculiar and rare pre-main sequence low-mass stars that are undergoing powerful accretion outbursts during their early stellar evolution. Although water masers are widespread in star-forming regions and serve as powerful probes of mass accretion and ejection on small scales, little is known about the prevalence of water masers toward FUors and EXors. Aims. We aim to perform the first systematic search for the 22.2 GHz water maser line in FUors and EXors in order to determine its overall incidence in these eruptive variables and to facilitate high angular-resolution follow-up observations. Methods. We used the Effelsberg 100-m radio telescope to observe the H2O (616 – 523) transition at 22.2GHz toward a sample of 51 eruptive young stellar objects. Results. We detected a total of five water masers in our survey; three are associated with eruptive stars, equivalent to a detection rate of ~6% for our sample of eruptive sources. These detections include one EXor, V512 Per (also known as SVS 13 or SVS 13A), and two FUors, Z CMa, and HH 354 IRS. This is the first reported detection of water maser emission towards HH 354 IRS. We also detected water maser emission in our pointing towards the FUor binary RNO 1B/1C, which most likely originates from the nearby deeply embedded source IRAS 00338+6312 (~4″ from RNO 1B/1C). Emission was also detected from H2O(B), (also known as SVS 13C), a Class 0 source ~30″ from the EXor V512 Per. The peak flux density of H2O(B) in our observations, 498.7 Jy, is the highest observed to date, indicating that we have serendipitously detected a water maser flare in this source. In addition to the two non-eruptive Class 0 sources (IRAS 00338+6312 and H2O(B)/SVS 13C), we detected maser emission towards one Class 0/I (HH 354 IRS) and two Class I (V512 Per/SVS 13A and Z CMa) eruptive stars. Conclusions. Despite the low detection rate, we demonstrate the presence of 22.2 GHz water maser emission in both FUor and EXor systems, paving the way to radio interferometric observations to study the environments of these eruptive stars on small scales. Comparisons of our data with historical observations spanning several decades suggest that multiple water maser flares have occurred in both V512 Per and H2O(B).Publisher PDFPeer reviewe
Multi-epoch VLBI of a double maser super burst
In a rare and spectacular display, two well-known massive star forming
regions, W49N and G25.65+1.05, recently underwent maser 'super burst' - their
fluxes suddenly increasing above 30,000 and 18,000 Jy, respectively, reaching
several orders of magnitude above their usual values. In quick-response, ToO
observations with the EVN, VLBA and KaVA were obtained constituting a 4 week
campaign - producing a high-cadence multi-epoch VLBI investigation of the maser
emission. The combination of high-resolution, polarisation and flux monitoring
during the burst provides one of the best accounts, to date, of the maser super
burst phenomenon, aiding their use as astrophysical tools. These proceedings
contain the preliminary results of our campaign
The evolution of the H2O maser emission in the accretion burst source G358.93-0.03
Context. The massive young stellar object (MYSO) G358.93-0.03-MM1 showed an extraordinary near-infrared- to (sub-)millimetredark and far-infrared-loud accretion burst, which is closely associated with flares of several class II methanol maser transitions, and, later, a 22 GHz water maser flare. Aims. Water maser flares provide an invaluable insight into ejection events associated with accretion bursts. Although the short timescale of the 22 GHz water maser flare made it impossible to carry out a very long baseline interferometry observation, we could track it with the Karl G. Jansky Very Large Array (VLA). Methods. The evolution of the spatial structure of the 22 GHz water masers and their association with the continuum sources in the region is studied with the VLA during two epochs, pre- and post-H2O maser flare. Results. A drastic change in the distribution of the water masers is revealed: in contrast to the four maser groups detected during epoch I, only two newly formed clusters are detected during epoch II. The 22 GHz water masers associated with the bursting source MM1 changed in morphology and emission velocity extent. Conclusions. Clear evidence of the influence of the accretion burst on the ejection from G358.93-0.03-MM1 is presented. The accretion event has also potentially affected a region with a radius of ∼200 (∼13 500AU at 6.75 kpc), suppressing water masers associated with other point sources in this region. © O. S. Bayandina et al. 2022.Japan Society for the Promotion of Science, KAKEN: JP21H00032, JP21H01120, JP24340034; Ministry of Education and Science of the Russian Federation, Minobrnauka: 075-15-2020-780; National Astronomical Observatory of Japan, NAOJAcknowledgements. The Ibaraki 6.7-GHz Methanol Maser Monitor (iMet) program is partially supported by the Inter-university collaborative project “Japanese VLBI Network (JVN)” of NAOJ and JSPS KAKENHI Grant Numbers JP24340034, JP21H01120, and JP21H00032 (YY). The National Radio Astronomy Observatory is a facility of the National Science Foundation operated under cooperative agreement by Associated Universities, Inc. This paper makes use of the following ALMA data: ADS/JAO.ALMA#2019.1.00768.S. ALMA is a partnership of ESO (representing its member states), NSF (USA) and NINS (Japan), together with NRC (Canada), MOST and ASIAA (Taiwan), and KASI (Republic of Korea), in cooperation with the Republic of Chile. The Joint ALMA Observatory is operated by ESO, AUI/NRAO and NAOJ. In addition, publications from NA authors must include the standard NRAO acknowledgement: The National Radio Astronomy Observatory is a facility of the National Science Foundation operated under cooperative agreement by Associated Universities, Inc. A.M.S. acknowledges support by the Ministry of Science and Higher Education of the Russian Federation under the grant 075-15-2020-780. A.C.G. acknowledges support by PRIN-INAF-MAIN-STREAM 2017 “Protoplanetary disks seen through the eyes of new-generation instruments” and by PRIN-INAF 2019 “Spectroscopically tracing the disk dispersal evolution (STRADE)”
A Multitransition Methanol Maser Study of the Accretion Burst Source G358.93-0.03-MM1
We present the most complete to date interferometric study of the centimeter-wavelength methanol masers detected in G358.93-0.03 at the burst and post-burst epochs. A unique, near-IR/(sub)millimeter-dark and far-IR-loud massive young stellar object accretion burst was recently discovered in G358.93-0.03. The event was accompanied by flares of an unprecedented number of rare methanol maser transitions. The first images of three of the newly discovered methanol masers at 6.18, 12.23, and 20.97 GHz are presented in this work. The spatial structure evolution of the methanol masers at 6.67, 12.18, and 23.12 GHz is studied at two epochs. The maser emission in all detected transitions resides in a region of 1/40.″2 around the bursting source and shows a clear velocity gradient in the north-south direction, with redshifted features to the north and blueshifted features to the south. A drastic change in the spatial morphology of the masing region is found: a dense and compact "spiral"cluster detected at epoch I evolved into a disperse, "round"structure at epoch II. During the transition from the first epoch to the second, the region traced by masers expanded. The comparison of our results with the complementary Very Large Array, very long baseline interferometry, Submillimeter Array, and Atacama Large Millimeter/submillimeter Array maser data is conducted. The obtained methanol maser data support the hypothesis of the presence of spiral arm structures within the accretion disk, which was suggested in previous studies of the source. © 2022. The Author(s). Published by the American Astronomical Society.The National Radio Astronomy Observatory is a facility of the National Science Foundation operated under cooperative agreement by Associated Universities, Inc. This paper makes use of the following ALMA data: ADS/JAO.ALMA#2018.A.00031.TS. ALMA is a partnership of ESO (representing its member states), NSF (USA) and NINS (Japan), together with NRC (Canada), MOST and ASIAA (Taiwan), and KASI (Republic of Korea), in cooperation with the Republic of Chile. The Joint ALMA Observatory is operated by ESO, AUI/NRAO and NAOJ. The SMA is a joint project between the Smithsonian Astrophysical Observatory and the Academia Sinica Institute of Astronomy and Astrophysics and is funded by the Smithsonian Institution and the Academia Sinica
VLBI observations of the G25.65+1.05 water maser superburst
This paper reports observations of a 22 GHz water maser 'superburst' in the G25.65+1.05 massive star-forming region, conducted in response to an alert from the Maser Monitoring Organisation (M2O). Very long baseline interferometry (VLBI) observations using the European VLBI Network (EVN) recorded a maser flux density of 1.2 × 104 Jy. The superburst was investipgated in the spectral, structural, and temporal domains and its cause was determined to be an increase in maser path length generated by the superposition of multiple maser emitting regions aligning in the line of sight to the observer. This conclusion was based on the location of the bursting maser in the context of the star-forming region, its complex structure, and its rapid onset and decay. © 2019 The Author(s) Published by Oxford University Press on behalf of the Royal Astronomical SocietyRAB acknowledges support through the EACOA Fellowship from the East Asian Core Observatories Association. GO acknowledges support from the Australian Research Council Discovery project DP180101061 funded by the Australian Government, the CAS ‘Light of West China’ Program 2018-XBQNXZ-B-021, and the National Key R&D Program of China 2018YFA0404602. TH is financially supported by the MEXT/JSPS KAKENHI Grant Number 17K05398. BM acknowledges support from the Spanish Ministerio de Economía y Competitividad (MINECO) under grants AYA2016-76012-C3-1-P and MDM-2014-0369 of ICCUB (Unidad de Excelencia ‘María de Maeztu’). NS acknowledges support from Russian Science Foundation grant 18-12-00193. AMS is supported by the Ministry of Science and High Education (the basic part of the State assignment, RK No. AAAA-A17-117030310283-7) and by the Act 211 Government of the Russian Federation, contract No.02.A03.21.0006. JOC acknowledges support by the Italian Ministry of Foreign Affairs and International ..