논문 상세보기

STUDY OF MILLI-JANSKY SEYFERT GALAXIES WITH STRONG FORBIDDEN HIGH-IONIZATION LINES USING THE VERY LARGE ARRAY SURVEY IMAGES KCI 등재 SCOPUS

  • 언어ENG
  • URLhttps://db.koreascholar.com/Article/Detail/383848
구독 기관 인증 시 무료 이용이 가능합니다. 4,600원
천문학회지 (Journal of The Korean Astronomical Society)
한국천문학회 (Korean Astronomical Society)
초록

We study the radio properties at 1.4 GHz of Seyfert galaxies with strong forbidden highionization lines (FHILs), selected from the Sloan Digital Sky Survey – a large-sized sample containing nearly equal proportion of diverse range of Seyfert galaxies showing similar redshift distributions compiled by Gelbord et al. (2009) using the Very Large Array survey images. The radio detection rate is low, 49%, which is lower than the detection rate of several other known Seyfert galaxy samples. These galaxies show low star formation rates and the radio emission is dominated by the active nucleus with ≤10% contribution from thermal emission, and possibly, none show evidence for relativistic beaming. The radio detection rate, distributions of radio power, and correlations between radio power and line luminosities or X-ray luminosity for narrow-line Seyfert 1 (NLS1), Seyfert 1 and Seyfert 2 galaxies are consistent with the predictions of the unified scheme hypothesis. Using correlation between radio and [O III]  5007°A luminosities, we show that ∼8% sample sources are radio-intermediate and the remaining are radio-quiet. There is possibly an ionization stratification associated with clouds on scales of 0.1–1.0 kpc, which have large optical depths at 1.4GHz, and it seems these clouds are responsible for free–free absorption of radio emission from the core; hence, leading to low radio detection rate for these FHIL-emitting Seyfert galaxies.

목차
Abstract
1. INTRODUCTION
2. BACKGROUND
    2.1. Classifications of Seyfert Galaxies
    2.2. FHIL-Emitting Seyfert Galaxy Sample
3. DATA
4. RESULTS
    4.1. Maps and Source Parameters
    4.2. Notes on Extended Sources
5. DISCUSSION
    5.1. The Radio Properties
    5.2. Correlations between Radio and Line Luminosities
    5.3. Starburst vs. AGN Nature of FHIL-EmittingSeyfert Nuclei
6. CONCLUSIONS AND FUTURE DIRECTIONS
REFERENCES
저자
  • Dharam V. Lal(National Centre for Radio Astrophysics (NCRA–TIFR), Pune University Campus) Corresponding author