相关论文: The Unusual Weak-Line Quasar PG1407+265 and its Fo…

PG 1115+080 is a quadruply lensed quasar at z=1.72 whose image positions are well fit by simple models of the lens galaxy (at z=0.31). At optical wavelengths, the bright close pair of images exhibits a modest flux ratio anomaly (factors of…

This is the second of two papers reporting observations and analysis of the unusually bright (m_b=14.4), luminous (M_B=-25.5), nearby (z=0.192) narrow-line quasar PHL 1811. The first paper reported that PHL 1811 is intrinsically X-ray weak,…

The object PG 0043+039 has been identified as a broad absorption line (BAL) quasar based on its UV spectra. However, this optical luminous quasar has not been detected before in deep X-ray observations, making it the most extreme X-ray weak…

We use the accretion disk/corona+jet model to fit the multi-band spectral energy distributions (SEDs) of two unusual radio-intermediate/quiet quasars. It is found that the optical/UV emission of III Zw 2 is probably dominated by the…

Using a 90 ks Chandra ACIS-S observation in the 0.3--7 keV band, along with complementary Low-Frequency Array and Karl G.~Jansky Very Large Array data in the 120--168 MHz and 1--2 GHz ranges, we study the diffuse emission around the nearby…

PG 1407+265 is a radio quiet quasar but has a relativistic jet. In this report, we show some peculiar properties of its optical and X-ray emissions, which indicate their possible non-thermal origins produced from jet. We use a simple…

We report on a multi-wavelength study of the unclassified X-ray source CXOU J110926.4-650224 (J1109). We identified the optical counterpart as a blue star with a magnitude of $\sim$20.1 (3300-10500 $\require{mediawiki-texvc} \AA$). The…

PG0043+039 has been identified as an extremely X-ray-weak quasar and as a peculiar broad-absorption-line quasar based on UV HST spectra. We took simultaneous deep X-ray observations of PG0043+039 with XMM-Newton and NuSTAR, UV spectra with…

We present two XMM-Newton observations of the luminous (L_x > 10^46 erg/s), radio-quiet quasar, PG 1407+265, separated by eleven months. The data indicate two distinct states: a highly variable, bright state (first epoch); and a quiescent,…

We present new X-ray timing and spectral results on the 8.0-second X-ray pulsar CXOU J010043.1-721134 from a series of observations using the Chandra X-ray Observatory. We find a spin period in 2004 January of 8.020392pm0.000009 seconds.…

We report a dramatic variability event in the X-ray history of the Narrow-Line quasar PHL 1092 (z=0.396). Our latest 2008 XMM-Newton observation reveals a flux drop of ~200 with respect to the previous observation performed about 4.5 years…

We report the discovery of an extreme X-ray flux rise (by a factor of > 20) of the weak-line quasar SDSS J153913.47+395423.4 (hereafter SDSS J1539+3954) at z = 1.935. SDSS J1539+3954 is the most-luminous object among radio-quiet type 1 AGNs…

(abridged) MR2251-178 was the first quasar initially discovered in X-rays, and the first one found to host a warm absorber. The quasar turned out to be an outstanding object in many respects. It has a high ratio of X-ray/optical luminosity,…

Our 5 ks Chandra ACIS-S observation of the globular cluster NGC 6652 detected 7 X-ray sources, 3 of which are previously unidentified. This cluster hosts a well-known bright low-mass X-ray binary, source A (or XB 1832-330). Source B shows…

We utilize recent NuSTAR observations (co-added depth $\approx55$-120 ks) of PG $1001+054$, PG $1254+047$, and PHL 1811 to constrain their hard X-ray ($\gtrsim5$ keV) weakness and spectral shapes, and thus to investigate the nature of their…

We report the discovery of a cluster of galaxies in the field of UM425, a pair of quasars separated by 6.5arcsec. Based on this finding, we revisit the long-standing question of whether this quasar pair is a binary quasar or a…

We report the discovery of the highly peculiar, radio-loud quasar VPMS J1342+2840 (z ~ 1.3) from the variability and proper motion survey. We present spectroscopic, imaging and photometric observations. The unusual spectrum shows a strong…

We report the results from an ASCA observation of the high-luminosity, radio-loud quasar PKS 0637-752 (redshift 0.654), covering the 0.8-15 keV band in the quasar-frame. We find the source to have a luminosity ~10^46 erg/s in the 2-10 keV…

We present a 100 ks Chandra observation studying the extended X-ray emission around the powerful z=1.04 quasar PKS1229-021. The diffuse cluster X-ray emission can be traced out to ~15 arcsec (~120 kpc) radius and there is a drop in the…

We report the discovery of a quasar at z = 7.07, which was selected from the deep multi-band imaging data collected by the Hyper Suprime-Cam (HSC) Subaru Strategic Program survey. This quasar, HSC J124353.93+010038.5, has an order of…