相关论文: Remarkable Spectral Variability of PDS 456

This is the first 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, focusing on the X-ray properties and the spectral energy…

In this work, the analysis of multi-epoch (1995-2010) X-ray observations of the Seyfert 1 galaxy H0557-385 is presented. The wealth of data presented in this analysis show that the source exhibits dramatic spectral variability, from a…

A number of recent lines of evidence point towards the presence of hot, out-flowing plasma from the central regions of compact Galactic and extragalactic X-ray sources. Additionally, it has long been noted that many of these sources exhibit…

We present the results obtained from broadband spectroscopy of the high mass X-ray binary 4U 1700-37 using data from a Suzaku observation in 2006 September 13-14 covering 0.29-0.72 orbital phase range. The light curves showed significant…

We present detailed broadband UV/optical to X-ray spectral variability of the Seyfert 1 galaxy 1H 0419-577 using six XMM-Newton observations performed during 2002-2003. These observations covered a large amplitude variability event in which…

We use the publicly available XMM-Newton archive to select a sample of 20 active galactic nuclei (AGN) known to exhibit reverberation signatures caused by the reflection of X-rays from the corona off the accretion disc that feeds the…

We present observations of the neutron star X-ray binary and relativistic jet source Circinus X-1 made at 4.8 and 8.6 GHz with the Australia Telescope Compact Array during a time interval of almost 10 years. The system shows significant…

(abridged) We firstly present the results of X-ray spectroscopic observations with XMM-Newton for four high-redshift radio-loud quasars at z>4. These observations more than double the number of z>4 radio-loud quasars having X-ray…

In the beginning of 2023 the Be transient X-ray pulsar RX J0440.9+4431 underwent a fist-ever giant outburst observed from the source peaking in the beginning of February and reaching peak luminosity of $\sim 4.3\times10^{37}$ erg s$^{-1}$.…

We examine archival XMM-Newton data on the extremely variable narrow-line Seyfert 1 (NLS1) active galactic nucleus (AGN) 1H 0707-495. We construct fractional excess variance (Fvar) spectra for each epoch, including the recent 2019…

We report on the first XMM-Newton observation of the highly X-ray variable, radio-quiet, Narrow-Line Seyfert 1 galaxy IRAS 13224-3809 obtained during the guaranteed time programme with a 64 ks exposure. The most remarkable spectral feature…

We present results from a new XMM-Newton observation of the high-redshift quasar RXJ1028.6-0844 at a redshift of 4.276. The soft X-ray spectral flattening, as reported by a study with ASCA previously (Yuan et al. 2000, ApJ 545, 625), is…

We report the detection of pulsations at 552 Hz in the rising phase of two type-I (thermonuclear) X-ray bursts observed from the accreting neutron star EXO 0748-676 in 2007 January and December, by the Rossi X-ray Timing Explorer. The…

We present the first high spectral resolution X-ray observation of the giant elliptical galaxy NGC 4636, obtained with the Reflection Grating Spectrometer on-board the XMM-Newton Observatory. The resulting spectrum contains a wealth of…

In 2021, the high-mass X-ray binary EXO 2030+375 underwent a giant X-ray outburst, the first since 2006, that reached a peak flux of ${\sim}600\,\mathrm{mCrab}$ (3-50\,keV). The goal of this work is to study the spectral evolution over the…

SDSS J120136.02+300305.5 was detected in an XMM-Newton slew from June 2010 with a flux 56 times higher than an upper limit from ROSAT, corresponding to Lx~3x10^44 ergs/s. It has the optical spectrum of a quiescent galaxy (z=0.146). Overall…

We present results of a systematic analysis of the XMM-Newton spectra of 40 quasars (QSOs) (z<1.72) from the Palomar-Green (PG) Bright Quasar Survey sample (M_B<-23). The sample includes 35 radio-quiet quasars (RQQs) and 5 radio-loud…

We report on a new XMM-Newton observation of NGC 247 from December 2009. The galaxy contains a supersoft, ultraluminous X-ray source (ULX) whose spectrum consists of a thermal component with a temperature about 0.1 keV and a power-law tail…

The bright eclipsing and bursting low-mass X-ray binary EXO 0748-676 has been observed at several occasions by XMM-Newton during the initial calibration and performance verification (CAL/PV) phase. We present here the results obtained from…

Aims. We examine the high energy resolution X-ray spectrum of the narrow-line Seyfert 1 galaxy Mrk 766 using 4 observations taken with XMM-Newton in 2005, to investigate the properties of the complex ionised absorber / emitter along the…