Database of molecular masers and variable stars

Соболев, А. М.; Ladeyschikov, D. A.; Nakashima, Jun-ichi

doi:10.1088/1674-4527/19/3/34

Cited by 10 publications

(7 citation statements)

References 16 publications

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“…In addition, Class I masers require lower densities and temperatures than Class II masers (Menten 2012), making them more numerous. Specifically for the J −1 → (J − 1) 0 − E series with J = 4 and 5, their intensities were predicted to be on the order of 50 mJy in the case of NGC 253 (Sobolev 1993).…”

Section: Introductionmentioning

confidence: 99%

Methanol masers in NGC 253 with ALCHEMI

Humire

Henkel

Hernández-Gómez

et al. 2022

A&A

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Context. Methanol masers of Class I (collisionally pumped) and Class II (radiatively pumped) have been studied in great detail in our Galaxy in a variety of astrophysical environments such as shocks and star-forming regions and are they are helpful to analyze the properties of the dense interstellar medium. However, the study of methanol masers in external galaxies is still in its infancy. Aims. Our main goal is to search for methanol masers in the central molecular zone (CMZ; inner 500 pc) of the nearby starburst galaxy NGC 253. Methods. Covering a frequency range between 84 and 373 GHz (λ = 3.6–0.8 mm) at high angular (1.″6 ∼ 27 pc) and spectral (∼8–9 km s−1) resolution with ALCHEMI (ALMA Comprehensive High-resolution Extragalactic Molecular Inventory), we have probed different regions across the CMZ of NGC 253. In order to look for methanol maser candidates, we employed the rotation diagram method and a set of radiative transfer models. Results. We detect for the first time masers above 84 GHz in NGC 253, covering an ample portion of the J−1 → (J − 1)0 − E line series (at 84, 132, 229, and 278 GHz) and the J0 → (J − 1)1 − A series (at 95, 146, and 198 GHz). This confirms the presence of the Class I maser line at 84 GHz, which was already reported, but now being detected in more than one location. For the J−1 → (J− 1)0 − E line series, we observe a lack of Class I maser candidates in the central star-forming disk. Conclusions. The physical conditions for maser excitation in the J−1 → (J − 1)0 − E line series can be weak shocks and cloud-cloud collisions as suggested by shock tracers (SiO and HNCO) in bi-symmetric shock regions located in the outskirts of the CMZ. On the other hand, the presence of photodissociation regions due to a high star-formation rate would be needed to explain the lack of Class I masers in the very central regions.

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Section: Introductionmentioning

confidence: 99%

Methanol masers in NGC 253 with ALCHEMI

Humire

Henkel

Hernández-Gómez

et al. 2022

A&A

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“…Three out of five objects were detected successfully in both frequencies, although the SNR in the weaker signals was ~2σ. The characteristics of the spectra and the obtained velocities were compared with results from scientific publications [12]- [14] and maser.db [15]. The obtained results were verified and considered correct.…”

Section: Resultsmentioning

confidence: 67%

Observations of Weak Galactic OH Masers in 1.6 GHz Frequency Band Using Irbene RT-32 Radio Telescope

Skirmante

Bezrukovs

Bleiders

et al. 2022

Latvian Journal of Physics and Technical Sciences

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Ventspils International Radio Astronomy Centre (Ventspils University of Applied Sciences) is implementing the scientific project “Complex Investigations of the Small Bodies in the Solar System” (lzp-2018/1-0401) related to the research of the small bodies in the Solar system (mainly, focusing on asteroids and comets) using methods of radio astronomy and signal processing. One of the research activities is weak hydroxyl (OH) radical observation in the radio range – single antenna observations using Irbene RT-32 radio telescope. To detect weak (0.1 Jy) OH masers of astronomical objects using radio methods, a research group in Ventspils adapted the Irbene RT-32 radio telescope working at 1665.402 and 1667.359 MHz frequencies. Spectral analysis using Fourier transform and continuous wavelet transform was applied to radio astronomical data from multiple observations related to weak OH maser detection. Multiple observation sessions of OH maser objects (R LMi, RU Ari, V524 Cas, OH 138.0+7.2, U Aur, etc) were carried out in 2020–2021.

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“…Class I methanol masers were detected not only in our Galaxy but in several external galaxies. More than 25 years ago, Sobolev (1993) suggested that search for extragalactic methanol masers should be most promising in the starburst galaxies in the 36.2 GHz class I methanol transition. After that, there were several unsuccessful searches for methanol masers in galaxies (Ellingsen et al 1994;Phillips et al 1998;Darling et al 2003), but these searches were focused on the class II transition at 6.7 GHz, probably inspired by the detection of 6.7 GHz methanol maser in LMC (Sinclair et al 1992).…”

Section: Introductionmentioning

confidence: 99%

Online Database of Class I Methanol Masers

Ladeyschikov

Bayandina

Соболев

2019

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In this paper, we present a database of class I methanol masers. The compiled information from the available literature provides an open and fast access to the data on class I methanol maser emission, including search, analysis and visualization of the extensive maser data set. There is information on individual maser components detected with single-dish observations and maser spots obtained from interferometric data. At the moment the database contains information from ∼100 papers, i.e. ∼7500 observations and ∼650 sites of class I methanol masers. Analysis of the data collected in the database shows that the distribution of class I methanol maser sources is similar to that of class II methanol masers. They are mostly found in the Molecular Ring, where majority of the OB stars are located. The difference between class I and II distributions is the presence of many class I methanol masers in the Nuclear Disk region (Central Molecular Zone). Access to the class I methanol maser database is available online at http://maserdb.net.

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Database of molecular masers and variable stars

Cited by 10 publications

References 16 publications

Methanol masers in NGC 253 with ALCHEMI

Methanol masers in NGC 253 with ALCHEMI

Observations of Weak Galactic OH Masers in 1.6 GHz Frequency Band Using Irbene RT-32 Radio Telescope

Online Database of Class I Methanol Masers

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