Bachev R., Strigachev A., Semkov E., 2005, MNRAS, 358, 774 “Short-term optical variability of high-redshift QSO's”
Bachev R., Marziani P., Sulentic J. W., Zamanov R., Calvani M., Dultzin-Hacyan D., 2004, ApJ 617, 171 “Average UV Quasar Spectra in the Context of Eigenvector 1: A Local Baldwin Effect Governed by Eddington Ratio?”
Bachev R., Strigachev A., 2004, AN, 325, No. 4, 1 (astro-ph/0310647): “Optical Continuum Variability of the Active Galaxy Mrk 279 - Implications for Different Accretion Regimes”
Bachev, R.; Strigachev, A.; Dimitrov, V. 2000, A&A Supl, 147, 175, “VRI comparison stars for selected active galaxies”
Bachev R., Slavcheva-Mihova L., 2000, Publ. Astr. Obs. Belgrade, 2000, 67, 3 "Search for Opyical Variability in Two Seyfert Galaxies",
Bachev, R., 1999, A&A, 348, 71 “Emission lines from illuminated warped accretion disks in AGN”
Bachev R. et al., 1999, Bulg. Journ. Phys., 5/6, 1, "Observations At Astronomical Observatory Belogradchik with CCD Camera SBIG ST-8"
Other refereed publications
Contadakis, M. E.; Avgoloupis, S.; Seiradakis, J.; Zhilyaev, B. E. Romanyuk, Ya. O.; Verlyuk, I. A.; Svyatogorov, O. A.; Khalack, V. R.; Sergeev, A. V.; Konstantinova-Antova, R. K.; Antov, A. P.; Bachev, R. S., and 3 coauthors , 2004, AN, 325, 427, “Detection of high-frequency optical oscillation during the flare phase of EV Lac in 1999”
Sulentic, J. W.; Zamfir, S.; Marziani, P.; Bachev, R.; Calvani, M.; Dultzin-Hacyan, D.; 2003, ApJ, 597, L17 “Radio-loud Active Galactic Nuclei in the Context of the Eigenvector 1 Parameter Space”
Marziani, P.; Sulentic, J. W.; Zamanov, R.; Calvani, M.; Dultzin-Hacyan, D.; Bachev, R.; Zwitter, T.; 2003, ApJS, 145, 199 “An Optical Spectroscopic Atlas of Low-Redshift Active Galactic Nuclei”
Zamanov, R.; Marziani, P.; Sulentic, J. W.; Calvani, M.; Dultzin-Hacyan, D.; Bachev, R., 2002, ApJ, 576, L9, “Kinematic Linkage between the Broad- and Narrow-Line-emitting Gas in Active Galactic Nuclei”
Sulentic, J. W.; Marziani, P.; Zamanov, R.; Bachev, R.; Calvani, M.; Dultzin-Hacyan, D., 2002, ApJ, 566, L71 “Average Quasar Spectra in the Context of Eigenvector 1”
Zhilyaev, B. E.; Romanyuk, Ya. O.; Verlyuk, I. A.; Svyatogorov, O. A.; Khalack, V. R.; Sergeev, A. V.; Konstantinova-Antova, R. K.; Antov, A. P.; Bachev, R. S.; Alekseev, I. Yu.; and 4 coauthors 2000, A&A, 364, 641 “Detection of high-frequency optical oscillations on the flare star EV Lacertae”
Zhilyaev, B. E.; Romanyuk, Ya. O.; Verlyuk, I. A.; Svyatogorov, O. A.; Khalack, V. R.; Sergeev, A. V.; Konstantinova-Antova, R. K.; Antov, A. P.; Bachev, R. S.; Alekseev, I. Yu.; and 4 coauthors, 2000, KFNTS, 3, 339 “High-frequency optical oscillations on the flare star EV Lacertae”
Konstantinova-Antova, R. K.; Antov, A. P.; Bachev, R. S., 2000, IBVS, 4867, 1, “Flares in the Active Giant V390 Aur”
Zhilyaev, B. E.; Verlyuk, I. A.; Romanyuk, Ya. O.; Svyatogorov, O. A.; Konstantinova-Antova, R. K.; Antov, A. P.; Bachev, R. S.; Alekseev, I. Yu.; Chalenko, V. E.; Shakhovskoy, D. N., 1998, A&A, 334, 931,“New features in the EV Lacertae flares discovered by fast high precision UBVRI photometry”
Conference proceedings
Semkov E., Strigachev A., Bachev R., 2005, Aerospace Research, Proceedings of the South-Eastern Astronomical Conference, Rozhen, 2004. "Spectra of bright quasars observed with the 2m Rozhen telescope"
Calvani M., Marziani P., Bachev R., Sulentic J. W., Zamanov R. K., Dultzin-Hacyan D., 2004, MmSAIS, 5, 223: ” Toward an Understanding of the Baldwin Effect: is the Eddington Ratio the Key Factor?”
Zamanov, R.; Marziani, P.; Sulentic, J. W.; Calvani, M.; Bachev, R.; Stirpe, G.; Dultzin-Hacyan, D., 2003, Memorie della Societa Astronomica Italiana Supplement, v.3, p.222, “Accretion Parameters and AGN Diversity”
Antov, A. P.; Bachev, R. S.; Boeva, S. S., 2001, Astronomische Gesellschaft Abstract Series, Vol. 18, “CCD Photometry of KR Aur with the 60 cm Telescope at Belogradchik Observatory”
Bachev, Rumen S., In: Balkan Meeting of Young Astronomers, 25 - 29 September 2000, Belogradchik, Bulgaria, 2001, p. 84 – 87 “Search for microvariability in Seyfert galaxies”
Bachev R., 1999, in "Activity in Galaxies and Related Phenomena", IAU 194, Armenia. Edited by Y. Terzian, E. Khachikian, and D. Weedman, San Francisco: Astronomical Soceity of the Pacific, p.313 "Bardeen-Petterson Effect and Broad HI Profiles of Seyferts",
Bachev R., Petrov G., Slavcheva L., Mihov B., , 1999, in "Activity in Galaxies and Related Phenomena", IAU 194, Armenia. Edited by Y. Terzian, E. Khachikian, and D. Weedman, San Francisco: Astronomical Soceity of the Pacific, p. 311,"Black Hole Masses and Unification of Seyferts"
Mihov B, Bachev R, Slavcheva L, Strigachev A., Petrov G., 1999, in "Activity in Galaxies and Related Phenomena", IAU 194, Armenia. Edited by Y. Terzian, E. Khachikian, and D. Weedman, San Francisco: Astronomical Soceity of the Pacific, p. 175. "Photometric Monitoring of Selected Quasars: The Highly Luminous Quasar HS 1946+7658"
Slavcheva L., Petrov G., Mihov B., Bachev R., , 1999, in "Activity in Galaxies and Related Phenomena", IAU 194, Armenia. Edited by Y. Terzian, E. Khachikian, and D. Weedman, San Francisco: Astronomical Soceity of the Pacific, p. 87 "Spectrophotometry of Selected AGN: Seyfert Galaxy AKN 564"
Petrov G., Slavcheva L., Mihov B., Bachev R., 1999, in "Activity in Galaxies and Related Phenomena", IAU 194, Armenia. Edited by Y. Terzian, E. Khachikian, and D. Weedman, San Francisco: Astronomical Soceity of the Pacific, p. 84 "Surface Photometry of Barred AGN Arakelian 564",
Bachev R., Petrov G. T., 1998, Comp. Rendus de l'Acad. Bulg. des Scien., 7/8 "On the Black Hole Masses, Accretion Rates and Unification of Seyfert Galaxies"