TY  - JOUR
AU  - Borka, Duško
AU  - Borka Jovanović, Vesna
AU  - Urosevic, D.
PY  - 2012
UR  - https://vinar.vin.bg.ac.rs/handle/123456789/4355
AB  - We use observations of the continuum radio emission at 1420, 820, 408, 34.5 and 22 MHz to estimate the mean brightness temperatures of the HB 21 supernova remnant (SNR) at five frequencies. We also present mean spectral index of HB 21. The spectra of LIB 21 are estimated from mean temperatures versus frequency plots for 1420, 820, 408, 34.5 and 22 MHz. We also present T - T plots of three frequency pairs: between 1420-34.5, 1420-22, 34.5-22 MHz. We notice flatter spectral indices at; frequencies below 408 MHz. Probably this is due to the absorption by thermal plasma at low frequencies.
T2  - Revista Mexicana de Astronomia y Astrofisica
T1  - Spectra of the Hb 21 Supernova Remnant: Evidence of Spectrum Flattening At the Low Frequencies
VL  - 48
IS  - 1
SP  - 53
EP  - 60
UR  - https://hdl.handle.net/21.15107/rcub_vinar_4355
ER  - 

@article{
author = "Borka, Duško and Borka Jovanović, Vesna and Urosevic, D.",
year = "2012",
abstract = "We use observations of the continuum radio emission at 1420, 820, 408, 34.5 and 22 MHz to estimate the mean brightness temperatures of the HB 21 supernova remnant (SNR) at five frequencies. We also present mean spectral index of HB 21. The spectra of LIB 21 are estimated from mean temperatures versus frequency plots for 1420, 820, 408, 34.5 and 22 MHz. We also present T - T plots of three frequency pairs: between 1420-34.5, 1420-22, 34.5-22 MHz. We notice flatter spectral indices at; frequencies below 408 MHz. Probably this is due to the absorption by thermal plasma at low frequencies.",
journal = "Revista Mexicana de Astronomia y Astrofisica",
title = "Spectra of the Hb 21 Supernova Remnant: Evidence of Spectrum Flattening At the Low Frequencies",
volume = "48",
number = "1",
pages = "53-60",
url = "https://hdl.handle.net/21.15107/rcub_vinar_4355"
}

Borka, D., Borka Jovanović, V.,& Urosevic, D.. (2012). Spectra of the Hb 21 Supernova Remnant: Evidence of Spectrum Flattening At the Low Frequencies. in Revista Mexicana de Astronomia y Astrofisica, 48(1), 53-60.
https://hdl.handle.net/21.15107/rcub_vinar_4355

Borka D, Borka Jovanović V, Urosevic D. Spectra of the Hb 21 Supernova Remnant: Evidence of Spectrum Flattening At the Low Frequencies. in Revista Mexicana de Astronomia y Astrofisica. 2012;48(1):53-60.
https://hdl.handle.net/21.15107/rcub_vinar_4355 .

Borka, Duško, Borka Jovanović, Vesna, Urosevic, D., "Spectra of the Hb 21 Supernova Remnant: Evidence of Spectrum Flattening At the Low Frequencies" in Revista Mexicana de Astronomia y Astrofisica, 48, no. 1 (2012):53-60,
https://hdl.handle.net/21.15107/rcub_vinar_4355 .

TY  - JOUR
AU  - Borka Jovanović, Vesna
AU  - Urosevic, D.
PY  - 2011
UR  - https://vinar.vin.bg.ac.rs/handle/123456789/4264
AB  - The estimated brightness of the Cygnus loop supernova remnant; (SNR) at 2720, 1420, 820, 408 and 34.5 MHz is presented. The observations of the continuum radio emission are used to calculate the mean brightness temperatures and surface brightnesses of this loop at the five frequencies in a wide spectral range, using the method we have previously developed for large radio loops. The spectrum for mean temperatures versus frequency between the five frequencies is estimated and the spectral index of the Cygnus loop is obtained. Also, from our results it; can be concluded that the Cygnus loop evolves in a low density environment and that the initial energy of the supernova explosion was relatively low. The results obtained confirm the non-thermal origin of the Cygnus radio loop and show that our method is applicable to almost all remnants.
T2  - Revista Mexicana de Astronomia y Astrofisica
T1  - Temperature, Brightness and Spectral Index of the Cygnus Radio Loop
VL  - 47
IS  - 1
SP  - 159
EP  - 171
UR  - https://hdl.handle.net/21.15107/rcub_vinar_4264
ER  - 

@article{
author = "Borka Jovanović, Vesna and Urosevic, D.",
year = "2011",
abstract = "The estimated brightness of the Cygnus loop supernova remnant; (SNR) at 2720, 1420, 820, 408 and 34.5 MHz is presented. The observations of the continuum radio emission are used to calculate the mean brightness temperatures and surface brightnesses of this loop at the five frequencies in a wide spectral range, using the method we have previously developed for large radio loops. The spectrum for mean temperatures versus frequency between the five frequencies is estimated and the spectral index of the Cygnus loop is obtained. Also, from our results it; can be concluded that the Cygnus loop evolves in a low density environment and that the initial energy of the supernova explosion was relatively low. The results obtained confirm the non-thermal origin of the Cygnus radio loop and show that our method is applicable to almost all remnants.",
journal = "Revista Mexicana de Astronomia y Astrofisica",
title = "Temperature, Brightness and Spectral Index of the Cygnus Radio Loop",
volume = "47",
number = "1",
pages = "159-171",
url = "https://hdl.handle.net/21.15107/rcub_vinar_4264"
}

Borka Jovanović, V.,& Urosevic, D.. (2011). Temperature, Brightness and Spectral Index of the Cygnus Radio Loop. in Revista Mexicana de Astronomia y Astrofisica, 47(1), 159-171.
https://hdl.handle.net/21.15107/rcub_vinar_4264

Borka Jovanović V, Urosevic D. Temperature, Brightness and Spectral Index of the Cygnus Radio Loop. in Revista Mexicana de Astronomia y Astrofisica. 2011;47(1):159-171.
https://hdl.handle.net/21.15107/rcub_vinar_4264 .

Borka Jovanović, Vesna, Urosevic, D., "Temperature, Brightness and Spectral Index of the Cygnus Radio Loop" in Revista Mexicana de Astronomia y Astrofisica, 47, no. 1 (2011):159-171,
https://hdl.handle.net/21.15107/rcub_vinar_4264 .