相关论文: The Road to Quasars

We report on an XMM-Newton observation of the z=1.055 quasar and Giga-hertz Peaked Spectrum (GPS) source 3C 287. Our 62.3 ksec observation provides an exceptional X-ray view of a prominent member of this important subclass of active…

We present optical spectroscopic data for a complete sample of 161 S_5GHz >= 0.2 Jy, flat-spectrum radio sources. The sources were observed as part of a survey for high redshift, radio-loud quasars, and were selected for spectroscopic…

This review provides the background and current perspective of some of the striking asymmetries exhibited by extragalactic double-lobed radio sources, paying special attention to the reported interrelationships among some of them. We…

We report the discovery of two radio-loud quasars with redshifts greater than four; GB1428+4217 with z=4.72 and GB1713+2148 with z=4.01. This doubles the number of published radio-selected quasars with z > 4, bringing the total to 4.…

The appearance of the jets and lobes of some radio galaxies makes it difficult to assign them to a known class of objects. This is often due to the activity of the central engine and/or interactions with the environment, as well as…

We have identified PKS 1018-42 as a radio galaxy with extraordinarily powerful jets, over twice as powerful as any 3CR source of equal or lesser redshift except for one (3C196). It is perhaps the most intrinsically powerful extragalactic…

We present the final observations of a complete sample of 37 radio galaxies from the Third Cambridge Catalog (3C) with redshift <0.3 and declination <20 degrees obtained with the VLT/MUSE optical integral field spectrograph. These data were…

The radio properties of 11 obscured `radio-intermediate' quasars at redshifts z>~2 have been investigated using the European Very-Long-Baseline-Interferometry Network (EVN) at 1.66 GHz. A sensitivity of ~25 micro Jy per 14x17 mas2 beam was…

We present new X-ray and optical spectroscopy of a Type 2 quasar candidate selected from a follow-up program of hard, optically-dim, serendipitous Chandra sources. The source is confirmed to be a Type 2 quasar at z=0.536 with an intrinsic…

We present a detailed analysis of the best-quality multi-wavelength data gathered for the large-scale jet in the core-dominated quasar 3C 273. We analyze all the archival observations of the target with the Chandra X-ray Observatory, the…

The uncharted territory of the high-redshift ($z\gtrsim3$) Universe holds the key to understand the evolution of quasars. In an attempt to identify the most extreme members of the quasar population, i.e., blazars, we have carried out a…

Quasars are the most luminous sources in the Universe. They are currently observed out to redshift z ~ 7 when the Universe was less than one tenth of its present age. Since their discovery 50 years ago astronomers have dreamed of using them…

Up to now, jet kinematic studies of radio quasars have barely reached beyond the redshift range at $z>3.5$. This significantly limits our knowledge of high-redshift jets, which can provide key information for understanding the jet nature…

The identification of bright quasars at z>6 enables detailed studies of supermassive black holes, massive galaxies, structure formation, and the state of the intergalactic medium within the first billion years after the Big Bang. We present…

We report on 1.7 and 5.0 GHz observations of the z=3.087 radio galaxy B3 J2330+3927, using the Very Long Baseline Array (VLBA), and archival 1.4 and 8.4 GHz Very Large Array (VLA) data. Our VLBA data identify a compact, flat spectrum…

We report the detection of an optical jet in the nearby Seyfert 1 radio galaxy 3C 120. The optical jet coincides with the well-known radio jet and emits continuum radiation (B,V',I) with a radio-to-optical spectral index of 0.65. There are…

Accurate alignment of the radio and optical celestial reference frames requires detailed understanding of physical factors that may cause offsets between the positions of the same object measured in different spectral bands. Opacity in…

We present details of a new sample of radio-loud quasars drawn from 0.013 sr of the 7C Redshift Survey. This sample is small (21 quasars) but complete in that every object with an unresolved nucleus and/or broad emission lines with…

The E3 giant elliptical galaxy NGC5018 was observed with the Chandra X-ray Observatory on 14 April 2001. Results of analysis of these X-ray data as well as of complementary optical, infrared, and radio data are reported. Seven X-ray point…

We present Keck spectropolarimetry of the highly polarized radio-loud quasar 3CR 68.1 (z=1.228, V=19). The polarization increases from 5 in the red (4000 A rest-frame) to >10% in the blue (1900 A rest-frame). The broad emission lines are…