Search

Your search keyword '"T Mufakharov"' showing total 6 results
Start Over Author "T Mufakharov"
6 results on '"T Mufakharov"'

1. Multimessenger Characterization of Markarian 501 during Historically Low X-Ray and γ-Ray Activity

Author

H. Abe, S. Abe, V. A. Acciari, I. Agudo, T. Aniello, S. Ansoldi, L. A. Antonelli, A. Arbet-Engels, C. Arcaro, M. Artero, K. Asano, D. Baack, A. Babić, A. Baquero, U. Barres de Almeida, J. A. Barrio, I. Batković, J. Baxter, J. Becerra González, W. Bednarek, E. Bernardini, M. Bernardos, A. Berti, J. Besenrieder, W. Bhattacharyya, C. Bigongiari, A. Biland, O. Blanch, G. Bonnoli, Ž. Bošnjak, I. Burelli, G. Busetto, R. Carosi, M. Carretero-Castrillo, A. J. Castro-Tirado, G. Ceribella, Y. Chai, A. Chilingarian, S. Cikota, E. Colombo, J. L. Contreras, J. Cortina, S. Covino, G. D’Amico, V. D’Elia, P. Da Vela, F. Dazzi, A. De Angelis, B. De Lotto, A. Del Popolo, M. Delfino, J. Delgado, C. Delgado Mendez, D. Depaoli, F. Di Pierro, L. Di Venere, E. Do Souto Espiñeira, D. Dominis Prester, A. Donini, D. Dorner, M. Doro, D. Elsaesser, G. Emery, J. Escudero, V. Fallah Ramazani, L. Fariña, A. Fattorini, L. Foffano, L. Font, C. Fruck, S. Fukami, Y. Fukazawa, R. J. García López, M. Garczarczyk, S. Gasparyan, M. Gaug, J. G. Giesbrecht Paiva, N. Giglietto, F. Giordano, P. Gliwny, N. Godinović, R. Grau, D. Green, J. G. Green, D. Hadasch, A. Hahn, T. Hassan, L. Heckmann, J. Herrera, D. Hrupec, M. Hütten, R. Imazawa, T. Inada, R. Iotov, K. Ishio, I. Jiménez Martínez, J. Jormanainen, D. Kerszberg, Y. Kobayashi, H. Kubo, J. Kushida, A. Lamastra, D. Lelas, F. Leone, E. Lindfors, L. Linhoff, S. Lombardi, F. Longo, R. López-Coto, M. López-Moya, A. López-Oramas, S. Loporchio, A. Lorini, E. Lyard, B. Machado de Oliveira Fraga, P. Majumdar, M. Makariev, G. Maneva, N. Mang, M. Manganaro, S. Mangano, K. Mannheim, M. Mariotti, M. Martínez, A. Mas-Aguilar, D. Mazin, S. Menchiari, S. Mender, S. Mićanović, D. Miceli, T. Miener, J. M. Miranda, R. Mirzoyan, E. Molina, H. A. Mondal, A. Moralejo, D. Morcuende, V. Moreno, T. Nakamori, C. Nanci, L. Nava, V. Neustroev, M. Nievas Rosillo, C. Nigro, K. Nilsson, K. Nishijima, T. Njoh Ekoume, K. Noda, S. Nozaki, Y. Ohtani, T. Oka, A. Okumura, J. Otero-Santos, S. Paiano, M. Palatiello, D. Paneque, R. Paoletti, J. M. Paredes, L. Pavletić, M. Persic, M. Pihet, G. Pirola, F. Podobnik, P. G. Prada Moroni, E. Prandini, G. Principe, C. Priyadarshi, W. Rhode, M. Ribó, J. Rico, C. Righi, A. Rugliancich, N. Sahakyan, T. Saito, S. Sakurai, K. Satalecka, F. G. Saturni, B. Schleicher, K. Schmidt, F. Schmuckermaier, J. L. Schubert, T. Schweizer, J. Sitarek, V. Sliusar, D. Sobczynska, A. Spolon, A. Stamerra, J. Strišković, D. Strom, M. Strzys, Y. Suda, T. Surić, H. Tajima, M. Takahashi, R. Takeishi, F. Tavecchio, P. Temnikov, K. Terauchi, T. Terzić, M. Teshima, L. Tosti, S. Truzzi, A. Tutone, S. Ubach, J. van Scherpenberg, M. Vazquez Acosta, S. Ventura, V. Verguilov, I. Viale, C. F. Vigorito, V. Vitale, I. Vovk, R. Walter, M. Will, C. Wunderlich, T. Yamamoto, D. Zarić, The MAGIC Collaboration, M. Cerruti, J. A. Acosta-Pulido, G. Apolonio, R. Bachev, M. Baloković, E. Benítez, I. Björklund, V. Bozhilov, L. F. Brown, A. Bugg, W. Carbonell, M. I. Carnerero, D. Carosati, C. Casadio, W. Chamani, W. P. Chen, R. A. Chigladze, G. Damljanovic, K. Epps, A. Erkenov, M. Feige, J. Finke, A. Fuentes, K. Gazeas, M. Giroletti, T. S. Grishina, A. C. Gupta, M. A. Gurwell,, E. Heidemann, D. Hiriart, W. J. Hou, T. Hovatta, S. Ibryamov, M. D. Joner, S. G. Jorstad, J. Kania, S. Kiehlmann, G. N. Kimeridze, E. N. Kopatskaya, M. Kopp, M. Korte, B. Kotas, S. Koyama, J. A. Kramer, L. Kunkel, S. O. Kurtanidze, O. M. Kurtanidze, A. Lähteenmäki, J. M. López, V. M. Larionov, E. G. Larionova, L. V. Larionova, C. Leto, C. Lorey, R. Mújica, G. M. Madejski, N. Marchili, A. P. Marscher, M. Minev, A. Modaressi, D. A. Morozova, T. Mufakharov, I. Myserlis, A. A. Nikiforova, M. G. Nikolashvili, E. Ovcharov, M. Perri, C. M. Raiteri, A. C. S. Readhead, A. Reimer, D. Reinhart, S. Righini, K. Rosenlehner, A. C. Sadun, S. S. Savchenko, A. Scherbantin, L. Schneider, K. Schoch, D. Seifert, E. Semkov, L. A. Sigua, C. Singh, P. Sola, Y. Sotnikova, M. Spencer, R. Steineke, M. Stojanovic, A. Strigachev, M. Tornikoski, E. Traianou, A. Tramacere, Yu. V. Troitskaya, I. S. Troitskiy, J. B. Trump, A. Tsai, A. Valcheva, A. A. Vasilyev, F. Verrecchia, M. Villata, O. Vince, K. Vrontaki, Z. R. Weaver, E. Zaharieva, and N. Zottmann

Subjects
Active galaxies, BL Lacertae objects, Markarian galaxies, Active galactic nuclei, Blazars, Astrophysics, QB460-466
Abstract

We study the broadband emission of Mrk 501 using multiwavelength observations from 2017 to 2020 performed with a multitude of instruments, involving, among others, MAGIC, Fermi's Large Area Telescope (LAT), NuSTAR, Swift, GASP-WEBT, and the Owens Valley Radio Observatory. Mrk 501 showed an extremely low broadband activity, which may help to unravel its baseline emission. Nonetheless, significant flux variations are detected at all wave bands, with the highest occurring at X-rays and very-high-energy (VHE) γ -rays. A significant correlation (>3 σ ) between X-rays and VHE γ -rays is measured, supporting leptonic scenarios to explain the variable parts of the emission, also during low activity. This is further supported when we extend our data from 2008 to 2020, and identify, for the first time, significant correlations between the Swift X-Ray Telescope and Fermi-LAT. We additionally find correlations between high-energy γ -rays and radio, with the radio lagging by more than 100 days, placing the γ -ray emission zone upstream of the radio-bright regions in the jet. Furthermore, Mrk 501 showed a historically low activity in X-rays and VHE γ -rays from mid-2017 to mid-2019 with a stable VHE flux (>0.2 TeV) of 5% the emission of the Crab Nebula. The broadband spectral energy distribution (SED) of this 2 yr long low state, the potential baseline emission of Mrk 501, can be characterized with one-zone leptonic models, and with (lepto)-hadronic models fulfilling neutrino flux constraints from IceCube. We explore the time evolution of the SED toward the low state, revealing that the stable baseline emission may be ascribed to a standing shock, and the variable emission to an additional expanding or traveling shock.

Published
2023
Full Text
View/download PDF

2. Investigating the multiwavelength behaviour of the flat spectrum radio quasar CTA 102 during 2013–2017

Author

F D’Ammando, C M Raiteri, M Villata, J A Acosta-Pulido, I Agudo, A A Arkharov, R Bachev, G V Baida, E Benítez, G A Borman, W Boschin, V Bozhilov, M S Butuzova, P Calcidese, M I Carnerero, D Carosati, C Casadio, N Castro-Segura, W-P Chen, G Damljanovic, A Di Paola, J Echevarría, N V Efimova, Sh A Ehgamberdiev, C Espinosa, A Fuentes, A Giunta, J L Gómez, T S Grishina, M A Gurwell, D Hiriart, H Jermak, B Jordan, S G Jorstad, M Joshi, G N Kimeridze, E N Kopatskaya, K Kuratov, O M Kurtanidze, S O Kurtanidze, A Lähteenmäki, V M Larionov, E G Larionova, L V Larionova, C Lázaro, C S Lin, M P Malmrose, A P Marscher, K Matsumoto, B McBreen, R Michel, B Mihov, M Minev, D O Mirzaqulov, S N Molina, J W Moody, D A Morozova, S V Nazarov, A A Nikiforova, M G Nikolashvili, J M Ohlert, N Okhmat, E Ovcharov, F Pinna, T A Polakis, C Protasio, T Pursimo, F J Redondo-Lorenzo, N Rizzi, G Rodriguez-Coira, K Sadakane, A C Sadun, M R Samal, S S Savchenko, E Semkov, L Sigua, B A Skiff, L Slavcheva-Mihova, P S Smith, I A Steele, A Strigachev, J Tammi, C Thum, M Tornikoski, Yu V Troitskaya, I S Troitsky, A A Vasilyev, O Vince, T Hovatta, S Kiehlmann, W Max-Moerbeck, A C S Readhead, R Reeves, T J Pearson, T Mufakharov, Yu V Sotnikova, and M G Mingaliev

Published
2019
Full Text
View/download PDF

3. Radio properties of quasars at z ≥ 3

Author

Yu. Kovalev, M. Mingaliev, A. Mikhailov, T. Mufakharov, and Yu. Sotnikova

Abstract

We studied the radio properties of optically selected quasars with z ≥ 3. The sample constructed with quasars having theflux densities S 1.4GHz ≥ 100 mJy at z ≥ 3 and S 1.4GHz ≥ 20 mJy at z ≥ 4. The observations were conducted in 2017–2021with the radio telescope RATAN-600. Using the multifrequency quasi-simultaneous data we revealed that a peaked spectralshape is a common feature for 50% of bright high-redshift quasars, the majority of them are radio-loud with log R > 2.5. Ourdata did not reveal any significant correlation between the redshift and spectral index. The average flux density variabilityof quasars are about V ar S = 0.2 − 1.0 at 4.7–11.2 GHz.

Published
2022
Full Text
View/download PDF

4. OH megamaser galaxies observations with RATAN-600

Author

Zh. Wu, V. Stolyarov, T. Semenova, N. Bursov, M. Mingaliev, T. Mufakharov, Yu. Sotnikova, and A. Mikhailov

Abstract

We present the results of pilot observations of the OH megamaser (OHM) sample carried out with the radio telescopeRATAN-600 at 1.2, 2.3, 4.7, 8.2, 11.2, and 22.3 GHz in 2019–2021. When comparing the radio continuum properties ofthe OHM sample and the control sample of galaxies without detected maser emission, we determine the median spectralindex at 4.7 GHz α 4.7 = −0.59 for the OHM sample, and α 4.7 = −0.71 for the non-OHM galaxies, and steep radiospectra prevail in both samples. Subsamples of OHMs powered by active galactic nuclei (AGN) and star formation have nosignificant differences in their radio properties. AGN-powered galaxies exhibit larger scatter in a range of parameters andtheir standard deviations.

Published
2022
Full Text
View/download PDF

5. Multi-wavelength observations of the BL Lac object Fermi J1544-0649: one year after its awakening

Author

T. Mufakharov, Albert K. H. Kong, Ning Jiang, C. W. Yang, P. H. T. Tam, Z. H. Zhong, Y. L. Ai, J. F. Fan, Y. Sotnikova, Partha Sarathi Pal, L. Z. Wang, B. T. Tang, Y. B. Li, Rong-Feng Shen, Liming Dou, J. Ding, Y. D. Cui, and J. Mao

Subjects
High Energy Astrophysical Phenomena (astro-ph.HE), Physics, 010308 nuclear & particles physics, Astrophysics::High Energy Astrophysical Phenomena, Radio flux, FOS: Physical sciences, Flux, Astronomy and Astrophysics, Multi wavelength, Astrophysics, Astrophysics::Cosmology and Extragalactic Astrophysics, 01 natural sciences, law.invention, Telescope, Space and Planetary Science, law, 0103 physical sciences, ROSAT, Astrophysics::Solar and Stellar Astrophysics, Astrophysics - High Energy Astrophysical Phenomena, 010303 astronomy & astrophysics, Cherenkov radiation, Astrophysics::Galaxy Astrophysics, Fermi Gamma-ray Space Telescope, BL Lac object
Abstract

We report observations of a transient source \fermi\ from radio to \grs. \fermi\ was discovered by the {\it Fermi-LAT} in May 2017. Follow-up {\it Swift-XRT} observations revealed three flaring episodes through March 2018, and the peak X-ray flux is about $10^3$ higher than the {\it ROSAT all-sky survey (RASS)} flux upper limit. Optical spectral measurements taken by the {\it Magellan 6.5-m telescope} and the {\it Lick-Shane telescope} both show a largely featureless spectrum, strengthening the BL Lac interpretation first proposed by \citet{Bruni18}. The optical and mid-infrared (MIR) emission goes to a higher state in 2018, when the flux in high energies goes down to a lower level. Our {\it RATAN-600m} measurements at 4.8~GHz and 8.2~GHz do not indicate any significant radio flux variation over the monitoring seasons in 2017 and 2018, nor deviate from the archival {\it NVSS} flux level. During GeV flaring times, the spectrum is very hard ($\Gamma_\gamma\sim$1.7) in the GeV band and at times also very hard (($\Gamma_{\rm X}\lesssim2$) in the X-rays, similar to a high-synchrotron-peak (or even an extreme) BL Lac object, making \fermi\ a good target for ground-based {\it Cherenkov telescopes}., Comment: Submitted in Journal of High Energy Astrophysics

Published
2020

6. A Systematic TMRT Observational Study of Galactic 12C/13C Ratios from Formaldehyde.

Author

Y. T. Yan, J. S. Zhang, C. Henkel, T. Mufakharov, L. W. Jia, X. D. Tang, Y. J. Wu, J. Li, Z. A. Zeng, Y. X. Wang, Y. Q. Li, J. Huang, and J. M. Jian

Subjects
HELIUM isotopes, FORMALDEHYDE, RADIO telescopes, MOLECULAR clouds, SPECTRAL lines, SCIENTIFIC observation, DEUTERIUM
Abstract

We present observations of the C-band 110–111 (4.8 GHz) and Ku-band 211–212 (14.5 GHz) K-doublet lines of H2CO and the C-band 110–111 (4.6 GHz) line of H213CO toward a large sample of Galactic molecular clouds, through the Shanghai Tianma 65 m radio telescope (TMRT). Our sample with 112 sources includes strong H2CO sources from the TMRT molecular line survey at C-band and other known H2CO sources. All three lines are detected toward 38 objects (43 radial velocity components) yielding a detection rate of 34%. Complementary observations of their continuum emission at both C- and Ku-bands were performed. Combining spectral line parameters and continuum data, we calculate the column densities, the optical depths and the isotope ratio H212CO/H213CO for each source. To evaluate photon trapping caused by sometimes significant opacities in the main isotopologue’s rotational mm-wave lines connecting our measured K-doublets, and to obtain 12C/13C abundance ratios, we used the RADEX non-LTE model accounting for radiative transfer effects. This implied the use of the new collision rates from Wiesenfeld & Faure. Also implementing distance values from trigonometric parallax measurements for our sources, we obtain a linear fit of 12C/13C = (5.08 ± 1.10)DGC + (11.86 ± 6.60), with a correlation coefficient of 0.58. DGC refers to Galactocentric distances. Our 12C/13C ratios agree very well with the ones deduced from CN and C18O but are lower than those previously reported on the basis of H2CO, tending to suggest that the bulk of the H2CO in our sources was formed on dust grain mantles and not in the gas phase. [ABSTRACT FROM AUTHOR]

Published
2019
Full Text
View/download PDF

Catalog

Books, media, physical & digital resources
See catalog results