期刊
ASTROPHYSICAL JOURNAL
卷 764, 期 2, 页码 -出版社
IOP PUBLISHING LTD
DOI: 10.1088/0004-637X/764/2/135
关键词
BL Lacertae objects: general; galaxies: active; gamma rays: galaxies; quasars: general; surveys
资金
- W. M. Keck Foundation
- STFC [ST/H002456/1]
- NASA [NNX09AW30G, NXX10AU09G, NAS5-00147]
- AST-0808050
- STFC [ST/K005596/1, ST/I003673/1, ST/G004331/1, PP/E003427/1, ST/H002456/1] Funding Source: UKRI
- NASA [NNX09AW30G, 104076] Funding Source: Federal RePORTER
- Science and Technology Facilities Council [ST/H002456/1, ST/G004331/1, ST/I003673/1, ST/K005596/1, PP/E003427/1] Funding Source: researchfish
We report on spectroscopic observations covering most of the 475 BL Lacs in the second Fermi Large Area Telescope (LAT) catalog of active galactic nuclei (AGNs). Including archival measurements (correcting several erroneous literature values) we now have spectroscopic redshifts for 44% of the BL Lacs. We establish firm lower redshift limits via intervening absorption systems and statistical lower limits via searches for host galaxies for an additional 51% of the sample leaving only 5% of the BL Lacs unconstrained. The new redshifts raise the median spectroscopic (z) over tilde from 0.23 to 0.33 and include redshifts as large as z = 2.471. Spectroscopic redshift minima from intervening absorbers have (z) over tilde = 0.70, showing a substantial fraction at large z and arguing against strong negative evolution. We find that detected BL Lac hosts are bright ellipticals with black hole masses M-circle similar to 10(8.5) - 10(9), substantially larger than the mean of optical AGNs and LAT Flat Spectrum Radio Quasar samples. A slow increase in M-circle with z may be due to selection bias. We find that the power-law dominance of the optical spectrum extends to extreme values, but this does not strongly correlate with the gamma-ray properties, suggesting that strong beaming is the primary cause of the range in continuum dominance.
作者
我是这篇论文的作者
点击您的名字以认领此论文并将其添加到您的个人资料中。
推荐
暂无数据