High Broad Line Research Articles

Radio dichotomy in quasars with H β FWHM greater than 15 000 km s−1

ABSTRACT It has been inferred from large unbiased samples that $10$–$15{{\ \rm per\ cent}}$ of all quasars are radio-loud (RL). Using the quasar catalogue from the Sloan Digital Sky Survey, we show that the radio-loud fraction (RLF) for high broad line (HBL) quasars, containing H β full width at half-maximum greater than 15 000 km s−1, is $\sim 57 {{\ \rm per\ cent}}$. While there is no significant difference between the RL and radio-quiet (RQ) populations in our sample in terms of their black hole mass, Eddington ratio, and covering fraction (CF), optical continuum luminosity of the RL quasars are higher. The similarity in the distribution of their CF indicates that our analysis is unbiased in terms of the viewing angle of the HBL RL and RQ quasars. Hence, we conclude that the accretion disc luminosity of the RL quasars in our HBL sample is higher, which indicates a connection between a brighter disc and a more prominent jet. By comparing them with the non-HBL H β broad emission line quasars, we find that the HBL sources have the lowest Eddington ratios in addition to having a very high RLF. That is consistent with the theories of jet formation, in which jets are launched from low Eddington ratio accreting systems. We find that the [O iii] narrow emission line is stronger in the RL compared to RQ quasars in our HBL sample, which is consistent with previous findings in the literature, and may be caused by the interaction of the narrow line gas with the jet.

Black hole mass, jet, and accretion disk connection: An analysis of radio‐loud and radio‐quiet quasars

AbstractSurveys have shown radio‐loud (RL) quasars constitute 10–15% of the total quasar population. However, it is unknown if the radio‐loud fraction (RL quasars/Total quasars) remains consistent among different parameter spaces. This study shows that radio‐loud fraction increases for increasing full width half maximum (FWHM) velocity of the Hβ and MgII broad emission line. Our data have been obtained from Shen, Y., Richards, G. T., Strauss, M. A. et al., ApJS, 194(2), 45, 2011 catalogue. To investigate the reason, in this preliminary study we analyze various properties like bolometric luminosity, optical continuum luminosity, black hole (BH) mass, and accretion rate of RL quasars and RQ quasars sample which have FWHM greater than 15,000 km s−1 (High broad line). From the distributions, we can conclude for all the properties in high broad line, RL quasars are having higher values than RQ quasars. We have predicted RL quasars are intrinsically brighter than RQ quasars and also predicted BH mass‐jet connection and accretion disk‐jet connection from our results but to conclude anything more analysis is needed.

Spectroscopic properties of radio-loud and radio-quiet quasars

AbstractSurveys have shown radio-loud (RL) quasars constitute 10%-15% of the total quasar population and rest are radio-quiet (RQ). However, it is unknown if this radio-loud fraction (RLF) remains consistent among different parameter spaces. This study shows that RLF increases for increasing full width half maximum (FWHM) velocity of the Hβ broad emission line (z < 0.75). To analyse the reason, we compared bolometric luminosity of RL and RQ quasars sample which have FWHM of Hβ broad emission line greater than 15000km/s (High Broad Line or HBL) with which have FWHM of Hβ emission line less than 2500km/s (Low Broad Line or LBL). From the distributions we can conclude for the HBL, RQ and RL quasars are peaking separately and RL quasars are having higher values whereas for the LBL the peaks are almost indistinguishable. We predicted selection effects could be the possible reason but to conclude anything more analysis is needed. Then we compared our result with Wills & Brotherton (1995) and have shown that some objects from our sample do not follow the pattern of the logR vs FWHM plot where R is the ratio of 5 GHz radio core flux density with the extended radio lobe flux density.