The transient X-ray source CXOM31 004205.77+411330.43 exhibited several outbursts during our long-term monitoring campaign of ~monthly observations of the M31 center with Chandra. However, the decay profile appears to be unlike those observed from Galactic transients. We followed up the 2011 outburst with two ~B band HST/ACS observations, one in outburst and the other in quiescence, and used difference imaging to search for a counterpart; this would be dominated by re-processed X-ray emission from the disk. We found a counterpart with B = 28.21+/-0.16. An XMM-Newton observation from a previous outburst yielded a spectrum that is well described by an absorbed power law with absorption equivalent to ~2.6 E+21 H atom cm^(-2) and photon index ~1.8; the highest quality Chandra spectrum yielded only $\sim$130 counts, and best fits consistent with the XMM-Newton results. We calculated an absolute V magnitude of +1.9 during outburst for a typical disk spectrum. An empirical relation between the ratio of X-ray to optical flux and orbital period suggests a period < ~4 hr for a black hole accretor. Such a short period is expected to yield an asymmetric, precessing disk, and we propose that the observed decay lightcurve is due to modulation of the mass transfer rate due to the disk precession.
We present a broad-band X-ray timing study of the variations in pulse behavior with superorbital cycle in the low-mass X-ray binary Her X-1. This source shows a 35-day superorbital modulation in X-ray flux that is likely caused by occultation by a warped, precessing accretion disk. Our data set consists of four joint XMM-Newton and NuSTAR observations of Her X-1 which sample a complete superorbital cycle. We focus our analysis on the first and fourth observations, which occur during the bright "main-on" phase, because these observations have strongly detected pulsations. We added an archival X…
We present a broad-band X-ray study of the effect of superorbital periods on X-ray spectra and pulse profiles in the neutron star X-ray binaries LMC X-4 and SMC X-1. These two sources display periodic or quasi-periodic variations in luminosity on the order of tens of days which are known to be superorbital, and are attributed to warped, precessing accretion disks. Using joint NuSTAR and XMM-Newton observations that span a complete superorbital cycle, we examine the broad-band spectra of these sources and find the shape to be well described by an absorbed power law with a soft blackbody compone…
The transient X-ray source XMMU J004215.8+411924 within M31 was found to be in outburst again in the 2010 May 27 Chandra observation. We present results from our four Chandra and seven Swift observations that covered this outburst. X-ray transient behaviour is generally caused by one of two things: mass accretion from a high mass companion during some restricted phase range in the orbital cycle, or disc instability in a low mass system. We aim to exploit Einstein, HST, Chandra and Swift observations to determine the nature of XMMU J004215.8+411924. We model the 2010 May spectrum, and use the r…
XMM J004243.6+412519 is a transient X-ray source in M31, first discovered 2012 January 15. Different approaches to fitting the brightest follow-up observation gave luminosities 1.3--2.5E+39 erg/s, making it the second ultraluminous X-ray source (ULX) in M31, with a probable black hole accretor. These different models represent different scenarios for the corona: optically thick and compact, or optically thin and extended. We obtained Chandra ACIS and {\em HST} ACS observations of this object as part of our transient monitoring program, and also observed it serendipitously in a 120 ks XMM-Newto…
We present a detailed analysis of the morphological properties of the Crab Nebula across the electromagnetic spectrum based on new and previous high-quality data from radio to X-rays. In the radio range we obtained an image of the entire nebula at 3 GHz with subarcsecond angular resolution using the VLA (NRAO) and an image at 100 GHz of the central region using the ALMA array. Simultaneously with the VLA observations we performed HST WFPC3 near infrared and Chandra X-ray observations of the central region of the nebula. In addition we produced a new UV image of the Crab nebula at 291 nm by co-…
In this paper we present the longest exposure (97 ks) XMM-Newton EPIC-pn spectrum ever obtained for the Seyfert 1.5 galaxy 1H 0419-577. With the aim of explaining the broadband emission of this source, we took advantage of the simultaneous coverage in the optical/UV that was provided in the present case by the XMM-Newton Optical Monitor and by a HST-COS observation. Archival FUSE flux measurements in the FUV were also used for the present analysis. We successfully modeled the X-ray spectrum together with the optical/UV fluxes data points using a Comptonization model. We found that a blackbody …
Jets have been detected in only a few symbiotic binaries to date, and CH Cyg is one of them. In 2001, a non-relativistic jet was detected in CH Cyg for the first time in X-rays. We carried out coordinated Chandra, HST, and VLA observations in 2008 to study the propagation of this jet and its interaction with the circumbinary medium. We detected the jet with Chandra and HST and determined that the apex has expanded to the South from about 300 AU to about 1400 AU, with the shock front propagating with velocity < 100 km/s. The shock front has significantly slowed down since 2001. Unexpectedly, we…
In this paper we analyze the X-ray, UV and optical data of the Seyfert 1.5 galaxy 1H0419-577, with the aim of detecting and studying an ionized-gas outflow. The source was observed simultaneously in the X-rays with XMM and in the UV with HST-COS. Optical data were also acquired with the XMM Optical Monitor. We detected a thin, lowly ionized warm absorber (log xi ~ 0.03, log NH ~19.9 cm^-2) in the X-ray spectrum, consistent to be produced by the same outflow already detected in the UV. Provided the gas density estimated in the UV, the outflow is consistent to be located in the host galaxy, at ~…
We investigate the nature of the ULX M81 X-6, which has been suggested to harbour a neutron star (NS), by studying its long-term X-ray spectral and temporal evolution, using the rich set of available archival data from XMM-Newton, Chandra, NuSTAR, and Swift/XRT. We tracked the evolution of the source on the hardness-intensity diagram and find that the source oscillates between two main states: one characterised by a hard and luminous spectrum and the other at low hardness and luminosity. The properties of the soft component remain constant between the two states, suggesting that changes in the…
The Seyfert Galaxy Mrk 335 is known for its frequent changes of flux and spectral shape in the X-ray band occurred during recent years. These variations may be explained by the onset of a wind that previous, non-contemporaneous high-resolution spectroscopy in X-ray and UV bands located at accretion disc scale. A simultaneous new campaign by XMM-Newton and HST caught the source at an historical low flux in the X-ray band. The soft X-ray spectrum is dominated by prominent emission features, and by the effect of a strong ionized absorber with an outflow velocity of 5-6X10$^3$~km~s$^{-1}$. The bro…
We present the analysis of archival XMM-Newton European Photon Imaging Camera (EPIC) X-ray observations of the symbiotic star R Aquarii. We used the Extended Source Analysis Software (ESAS) package to disclose diffuse soft X-ray emission extending up to 2.2 arcmin ($\approx$0.27 pc) from this binary system. The depth of these XMM-Newton EPIC observations reveal in unprecedented detail the spatial distribution of this diffuse emission, with a bipolar morphology spatially correlated with the optical nebula. The extended X-ray emission shares the same dominant soft X-ray-emitting temperature as t…
We present the discovery of an outflowing ionized wind in the Seyfert 1 Galaxy Mrk 335. Despite having been extensively observed by most of the largest X-ray observatories in the last decade, this bright source was not known to host warm absorber gas until recent XMM-Newton observations in combination with a long-term Swift monitoring program have shown extreme flux and spectral variability. High resolution spectra obtained by the XMM-Newton RGS detector reveal that the wind consists of three distinct ionization components, all outflowing at a velocity of 5000 km/s. This wind is clearly reveal…
We report on X-ray observations of the radio-intermediate, X-ray bright Seyfert 1 galaxy, III Zw 2, obtained with XMM-Newton, Suzaku, and Swift over the past 17-years. The source brightness varies significantly over yearly time scales, but more modestly over periods of days. Pointed observations with XMM-Newton in 2000 and Suzaku in 2011 show spectral differences despite comparable X-ray fluxes. The Suzaku spectra are consistent with a power law continuum and a narrow Gaussian emission feature at ~6.4 keV, whereas the earlier XMM-Newton spectrum requires a broader Gaussian profile and soft-exc…
Evolution of the recent high-accretion state of the recurrent nova T CrB: HST, Swift, NuSTAR, and XMM-Newton observations
Universidad Nacional de Hurlingham (UNAHUR)（乌尔沙姆国立大学）；Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET)（国家科学技术研究委员会）；Mullard Space Science Laboratory, University College London（伦敦大学学院穆拉德太空科学实验室）；NASA Goddard Space Flight Center（美国宇航局戈达德太空飞行中心）；University of Maryland, Baltimore County（马里兰大学巴尔的摩县分校）；Columbia University（哥伦比亚大学）；School of Physics and Astronomy, University of Leicester（莱斯特大学物理与天文学学院）
We present a 140ks observation of NGC 4593 with XMM-Newton providing simultaneous and continuous PN X-ray and OM UV (UVW1 2910Å) lightcurves which sample short-timescale variations better than previous observations. These observations were simultaneous with 22d of Swift X-ray and UV/optical monitoring, reported previously, and 4d of AstroSat X-ray (SXT), far (FUV 1541Å), and near (NUV 2632Å) UV allowing lag measurements between them and the highly-sampled XMM. From the XMM we find that UVW1 lags behind the X-rays by 29.5$\pm$1.3ks, $\sim$half the lag previously determined from the Swift monito…
In this work, a nearby luminous AGN sample is selected from HST, where only sources with both X-ray emission observed by \textit{Chandra/XMM-Newton} and radio flux detected by VLA/VLBA/VLBI/MERLIN are adopted to keep high precision. We get a sample of 30 luminous AGNs finally, which consist of 11 RLAGN and 19 RQAGN. It is found that the relationship between $R_{\rm {UV}}$ and $α_{\rm {ox}}$, which was firstly reported by Li & Xie (2017) in LLAGN, and other relationships are all absent in RLAGN, probably due to the complex physical process therein. Our results indicate that the X-ray emission f…
We study the X-ray and optical properties of the ultraluminous X-ray source (ULX) X-6 in the nearby galaxy NGC 4258 (M106) based on the archival {\it XMM-Newton}, {\it Chandra}, {\it Swift}, and {\it Hubble Space Telescope} ({\it HST}) observations. The source has a peak luminosity of $L_{\mathrm{X}} \sim 2 \times 10^{39}$ erg s$^{-1}$ in the {\it XMM-Newton} observation of 2004 June. Consideration of the hardness ratios and spectral model parameters shows that the source seems to exhibit possible spectral variations throughout the X-ray observations. In the images from the {\it HST}/Advanced …
We present the results of a search for the nature of ultraluminous X-ray source (ULX) X-3 in the nearby galaxy NGC 4258. We use archival data from {\it XMM-Newton}, {\it Chandra}, {\it NuSTAR} and {\it HST} observations. Total X-ray data analysed to find the model parameters of the system is indicative of a stellar mass black hole, $\sim$ 10 M$_{\sun}$, as the central compact object. Furthermore, analyses of the optical data from {\it HST} reveal two optical candidates with the 90 per cent confidence level of error radius of 0$\farcs$28. Assuming the optical emission is dominated by the donor …
We recently discovered the X-ray/optical outbursting source 3XMM J215022.4-055108. It was best explained as the tidal disruption of a star by an intermediate-mass black hole of mass of a few tens of thousand solar masses in a massive star cluster at the outskirts of a large barred lenticular galaxy at D_L=247 Mpc. However, we could not completely rule out a Galactic cooling neutron star as an alternative explanation for the source. In order to further pin down the nature of the source, we have obtained new multiwavelength observations by XMM-Newton and Hubble Space Telescope (HST). The optical…
From Swift monitoring of a sample of active galactic nuclei (AGN) we found a transient X-ray obscuration event in Seyfert-1 galaxy NGC 3227, and thus triggered our joint XMM-Newton, NuSTAR, and Hubble Space Telescope (HST) observations to study this event. Here in the first paper of our series we present the broadband continuum modelling of the spectral energy distribution (SED) for NGC 3227, extending from near infrared (NIR) to hard X-rays. We use our new spectra taken with XMM-Newton, NuSTAR, and HST/COS in 2019, together with archival unobscured XMM-Newton, NuSTAR, and HST/STIS data, in or…
In this work, we deploy archival data from {\it HST}, {\it Chandra}, {\it XMM-Newton}, and {\it Swift-XRT}, to probe the nature of 9 candidate ULXs in NGC 1672. Specifically, our study focuses on using the precise source positions obtained via improved astrometry based on {\it Chandra} and {\it HST} observations to search for and identify potential optical counterparts for these ULXs. Unique optical counterparts are identified for two of the ULX candidates i.e., X2 and X6; for three of the candidates i.e., X1, X5 and X7, we found two potential counterparts for each source within the respective…
Archival {\it XMM-Newton}, {\it Chandra} and {\it Hubble Space Telescope (HST)} data have been used to study the X-ray and optical properties of two candidate ultraluminous X-ray sources (ULXs) in NGC\,4536. In order to search for potential optical counterparts, relative astrometry between {\it Chandra} and {\it HST} was improved, and as a result, optical counterparts were detected for both X-ray sources. To complement our findings (based on the archival data), ground-based optical spectra of the counterparts were obtained with the 6m BTA Telescope located at the Special Astrophysical Observat…
We report the detection of an extended X-ray nebulosity with an elongation from northeast to southwest in excess of 15$^{\prime\prime}$ in a radial profile and imaging of the recurrent nova T Pyx using the archival data obtained with the X-ray Multi-Mirror Mission (XMM), European Photon Imaging Camera (pn instrument). The signal to noise ratio (S/N) in the extended emission (above the point source and the background) is 5.2 over the 0.3-9.0 keV energy range and 4.9 over the 0.3-1.5 keV energy range. We calculate an absorbed X-ray flux of 2.3$\times10^{-14}$ erg cm$^{-2}$ s$^{-1}$ with a lumino…
We performed a search for eclipsing and dipping sources in the archive of the EXTraS project - a systematic characterization of the temporal behaviour of XMM-Newton point sources. We discovered dips in the X-ray light curve of 3XMM J004232.1+411314, which has been recently associated with the hard X-ray source dominating the emission of M31. A systematic analysis of XMM-Newton observations revealed 13 dips in 40 observations (total exposure time $\sim$0.8 Ms). Among them, four observations show two dips, separated by $\sim$4.01 hr. Dip depths and durations are variable. The dips occur only dur…
We report on Chandra observations of the bright ultra-luminous X-ray (ULX) source in NGC3921. Previous XMM observations reported in the literature show the presence of a bright ULX at a 0.5-10 keV luminosity of 2x10^40 erg/s. Our Chandra observation finds the source at a lower luminosity of ~8x10^39 erg/s, furthermore, we provide a Chandra position of the ULX accurate to 0.7" at 90% confidence. The X-ray variability makes it unlikely that the high luminosity is caused by several separate X-ray sources. In 3 epochs of archival Hubble Space Telescope (HST) observations we find a candidate counte…
We report the X-ray data analysis of two transient ultraluminous X-ray sources (ULXs, hereafter X1 and X2) located in the nearby galaxy NGC 7090. While they were not detected in the 2004 XMM-Newton and 2005 Chandra observations, their 0.3-10 keV X-ray luminosities reached $>3\times10^{39}\,\mathrm{erg\,s^{-1}}$ in later XMM-Newton or Swift observations, showing increases in flux by a factor of $>80$ and $>300$ for X1 and X2, respectively. X1 showed indications of spectral variability: at the highest luminosity, its X-ray spectra can be fitted with a powerlaw ($Γ=1.55\pm0.15$), or a multicolour…
AK~Sco stands out among pre-main sequence binaries because of its prominent ultraviolet excess, the high eccentricity of its orbit and the strong tides driven by it. AK Sco consists of two F5 type stars that get as close as 11R$_*$ at periastron passage. The presence of a dense ($n_e \sim 10^{11}$~cm$^{-3}$) extended envelope has been unveiled recently. In this article, we report the results from a XMM-Newton based monitoring of the system. We show that at periastron, X-ray and UV fluxes are enhanced by a factor of $\sim 3$ with respect to the apastron values. The X-ray radiation is produced i…
We present XMM-Newton, NuSTAR, Swift and Hubble Space Telescope observations of the Narrow-line Seyfert 1 galaxy Mrk 335 in a protracted low state in 2018 and 2019. The X-ray flux is at the lowest level so far observed, and the extremely low continuum flux reveals a host of soft X-ray emission lines from photoionised gas. The simultaneous UV flux drop suggests that the variability is intrinsic to the source, and we confirm this with broad-band X-ray spectroscopy. The dominance of the soft X-ray lines at low energies and distant reflection at high energies is therefore due to the respective emi…
We present a detailed optical and X-ray study of the 2013 outburst of the Small Magellanic Cloud Be/X-ray binary SXP7.92, as well as an overview of the last 18 years of observations from OGLE, RXTE, Chandra and XMM-Newton. We revise the position of this source to RA(J2000)=00:57:58.4, Dec(J2000)=-72:22:29.5 with a $1σ$ uncertainty of 1.5 arcsec, correcting the previously reported position by Coe et al. (2009) by more than 20 arcminutes. We identify and spectrally classify the correct counterpart as a B1Ve star. The optical spectrum is distinguished by an uncharacteristically deep narrow Balmer…
We report the most accurate X-ray position of the X-ray source in the giant globular cluster G1 in M31 by using the Chandra X-ray Observatory, Hubble Space Telescope (HST), and Canada-France-Hawaii Telescope (CFHT). G1 is clearly detected with Chandra and by cross-registering with HST and CFHT images, we derive a 1-sigma error radius of 0.15 arcsec, significantly smaller than the previous measurement by XMM-Newton. We conclude that the X-ray emission of G1 is likely to come from within the core radius of the cluster. We have considered a number of possibilities for the origin of the X-ray emis…
A deep X-ray and UV look into the reflaring stage of the accreting millisecond pulsar SAX J1808.4-3658
INAF - Osservatorio Astronomico di Roma（意大利国家天体物理研究所罗马天文台）；Sapienza Università di Roma（罗马第一大学）；ASI - Agenzia Spaziale Italiana（意大利航天局）；INAF - Osservatorio Astronomico di Brera（意大利国家天体物理研究所布雷拉天文台）；Università di Palermo（巴勒莫大学）；Dipartimento di Fisica e Chimica - Emilio Segrè, Università di Palermo（巴勒莫大学埃米利奥·塞格雷物理化学系）；Dipartimento di Fisica, Università degli Studi di Cagliari（卡利亚里大学物理系）；INAF/IASF Palermo（意大利国家天体物理研究所帕勒莫空间物理研究所）；Institute of Space Sciences (ICE, CSIC)（空间科学研究所（西班牙高等科学研究委员会））；Institut d’Estudis Espacials de Catalunya (IEEC)（加泰罗尼亚空间研究学院）
A multifrequency campaign on the BL Lac object PG 1553+113 was organized by the Whole Earth Blazar Telescope (WEBT) in 2013 April-August, involving 19 optical, two near-IR, and three radio telescopes. The aim was to study the source behaviour at low energies during and around the high-energy observations by the Major Atmospheric Gamma-ray Imaging Cherenkov (MAGIC) telescopes in April-July. We also analyse the UV and X-ray data acquired by the Swift and XMM-Newton satellites in the same period. The WEBT and satellite observations allow us to detail the synchrotron emission bump in the source sp…
In 2013 we conducted a large multi-wavelength campaign on the archetypical Seyfert 1 galaxy NGC 5548. Unexpectedly, this usually unobscured source appeared strongly absorbed in the soft X-rays during the entire campaign, and signatures of new and strong outflows were present in the almost simultaneous UV HST/COS data. Here we carry out a comprehensive spectral analysis of all available XMM-Newton observations of NGC 5548 (for a total of ~763 ks) in combination with 3 simultaneous NuSTAR obs. We obtain a best-fit composed by i) a weakly varying flat (Gamma~1.5-1.7) power-law component; ii) a co…
We present a multiwavelength examination of the supernova remnant (SNR) S26 in the nearby galaxy NGC 300 using data from Chandra X-ray Observatory, XMM-Newton X-ray Observatory, Hubble Space Telescope (HST), the Very Large Array, and the Australia Telescope Compact Array. We simultaneously fit all of the available X-ray data with a thermal plasma model and find a temperature of $0.77 \pm 0.13$ keV with a hydrogen column density of ($9.7^{+6.4}_{-4.8}$)$\times 10^{20}$ cm$^{-2}$. HST imaging allows us to measure a semimajor axis of $0.78 \pm 0.10$ arcsec ($7.5 \pm 1.0$ pc) and a semiminor axis …
We report on results from a one-year soft X-ray observing campaign of the ultraluminous X-ray pulsar NGC 300 ULX-1 by the Neutron star Interior Composition Explorer (NICER) during 2018--2019. Our analysis also made use of data from Swift/XRT and XMM-Newton in order to model and remove contamination from the nearby eclipsing X-ray binary NGC 300 X-1. We constructed and fitted a series of 5-day averaged NICER spectra of NGC 300 ULX-1 in the 0.4--4.0 keV range to evaluate the long-term spectral evolution of the source, and found that an absorbed power-law model provided the best fit overall. Over…
We conducted a multi-wavelength six-month campaign to observe the Seyfert galaxy NGC~7469, using the space-based observatories \textit{HST}, \textit{Swift}, \textit{XMM-Newton} and \textit{NuSTAR}. Here we report the results of the spectral analysis of the 7 simultaneous \textit{XMM-Newton} and \textit{NuSTAR} observations. The sources shows significant flux variability within each observation, but the average flux is less variable among the different pointings of our campaign. Our spectral analysis reveals a prominent narrow neutral \ion{Fe} K$α$ emission line in all the spectra, with weaker …
We report the detection of X-ray emission from the symbiotic star V1329 Cyg with XMM-Newton. The spectrum from the EPIC pn, MOS1 and MOS2 instruments consists of a two-temperature plasma with k T = 0.11 keV and k T = 0.93 keV. Unlike the vast majority of symbiotic stars detected in X-rays, the soft component of the spectrum seems to be absorbed only by interstellar material. The shock velocities corresponding to the observed temperatures are about 300 km/s and about 900 km/s. We did not find either periodic or aperiodic X-ray variability, with upper limits on the amplitudes of such variations …
We report on the discovery of a UV absorption counterpart of a low-ionization X-ray ultra-fast outflow (UFO) in the Narrow-Line Seyfert-1 galaxy IRAS 17020+4544. This UV signature of the UFO is seen as a narrow and blueshifted Lyman-alpha absorption feature in the far-UV spectrum, taken with the Cosmic Origins Spectrograph (COS) on the Hubble Space Telescope (HST). The Lyman-alpha feature is found to be outflowing with a velocity of -23430 km/s (0.078 c). We carry out high-resolution UV spectroscopy and photoionization modeling to study the UFO that is seen in the HTS/COS spectrum. The results…
We identified a new X-ray transient CXOM31 004252.457+411631.17 (T13) in M31 during a 2013 June Chandra observation. This system is particularly exciting because it is located within 100" of M31*; it is thought that this region of the bulge is sufficiently dense to form X-ray binaries dynamicaly, but only systems with black hole accretors and/or short periods are expected to survive. A follow-up XMM-Newton observation yielded a soft spectrum, well described by a 0.39+/-0.02 keV disk blackbody; applying this model to the Chandra observation yielded an observed 0.3--10 keV luminosity peak of 6.2…
Hercules X-1 is a nearly edge-on accreting X-ray pulsar with a warped accretion disk, precessing with a period of about 35 days. The disk precession allows for unique and changing sightlines towards the X-ray source. To investigate the accretion flow at a variety of sightlines, we obtained a large observational campaign on Her X-1 with XMM-Newton (380 ks exposure) and Chandra (50 ks exposure) for a significant fraction of a single disk precession cycle, resulting in one of the best datasets taken to date on a neutron star X-ray binary. Here we present the spectral analysis of the High State hi…
A growing number of transient X-ray obscuration events in type I AGN suggest that our line-of-sight to the central engine is not always free. Multiple X-ray obscuration events have been reported in the nearby Seyfert 1.5 galaxy NGC 3227 from 2000 to 2016. In late 2019, another X-ray obscuration event was identified with Swift. Two coordinated target-of-opportunity observations with XMM-Newton, NuSTAR, and HST/COS were triggered in Nov. and Dec. 2019 to study this obscuration event. For each observation, we analyze the time-averaged X-ray spectra. We perform photoionization modeling with the SP…
We present new Karl G. Jansky Very Large Array (VLA, 1.5 GHz) radio data for the giant elliptical galaxy IC 4296, supported by archival radio, X-ray (Chandra, XMM-Newton) and optical (SOAR, HST) observations. The galaxy hosts powerful radio jets piercing through the inner hot X-ray emitting atmosphere, depositing most of the energy into the ambient intra-cluster medium (ICM). Whereas the radio surface brightness of the A configuration image is consistent with a Fanaroff-Riley Class I (FR I) system, the D configuration image shows two bright, relative to the central region, large (~160 kpc diam…
The bright Seyfert 1 galaxy Mrk 509 was monitored by XMM-Newton and other satellites in 2009 to constrain the location of the outflow. We have studied the response of the photoionised gas to changes in the ionising flux produced by the central regions. We used the 5 discrete ionisation components A-E detected in the time-averaged spectrum taken with the RGS. Using the ratio of fluxed EPIC and RGS spectra, we put tight constraints on the variability of the absorbers. Monitoring with the Swift satellite started 6 weeks before the XMM-Newton observations, allowing to use the ionising flux history…
We present the analysis of XMM-Newton and Swift optical-UV and X-ray observations of the Seyfert-1/QSO Mrk 509, part of an unprecedented multi-wavelength campaign, investigating the nuclear environment of this AGN. The XMM-Newton data are from a series of 10 observations of about 60 ks each, spaced from each other by about 4 days, taken in Oct-Nov 2009. During our campaign, Mrk 509 was also observed with Swift for a period of about 100 days, monitoring the behaviour of the source before and after the XMM-Newton observations. With these data we have established the continuum spectrum in the opt…
We present the results of a temporal and spectral analysis of the transient source ULX-4 in the galaxy M51. The data used were drawn from Chandra, XMM-Newton and Swift-XRT archives, spanning the years 2000-2019. The X-ray flux of the source is seen to vary by two orders of magnitudes within a month but a short-term variability was not observed over the time intervals of 100-2000 second in the 0.3-10 keV energy band. We find some evidence for the existence of bi-modality feature in the flux distribution of ULX-4. We identified two optical sources as possible counterparts within an error radius …
Simultaneous XMM-Newton, NuSTAR and HST observations, performed in March 2017, of the nearby ($z=0.184$) luminous quasar PDS 456 are presented. PDS 456 had a low X-ray flux compared to past observations, where the first of the two new XMM-Newton observations occurred during a pronounced dip in the X-ray lightcurve. The broad-band X-ray spectrum is highly absorbed, attenuated by a soft X-ray absorber of column density $N_{\rm H}=6\times10^{22}$ cm$^{-2}$. An increase in obscuration occurs during the dip, which may be due to an X-ray eclipse. In addition, the persistent, fast Fe K outflow is pre…
XRISM/Resolve observations of Hercules X-1: vertical structure and kinematics of the disk wind
Center for Astrophysics — Harvard & Smithsonian（哈佛-史密森尼天体物理中心）；MIT Kavli Institute for Astrophysics and Space Research, Massachusetts Institute of Technology（麻省理工学院卡弗里天体物理与空间研究所）；Department of Physics, Graduate School of Science, Kyoto University（京都大学理学研究科物理学系）；Institut für Astronomie und Astrophysik, Universität Tübingen（蒂宾根大学天文与天体物理研究所）；Università degli Studi di Palermo, Dipartimento di Fisica e Chimica（巴勒莫大学物理与化学系）；Institute of Astronomy, Madingley Road, Cambridge（剑桥大学天体物理研究所）；Department of Astronomy, University of Michigan（密歇根大学天文学系）；INAF—IASF Palermo（意大利国家天体物理研究所巴勒莫分部）
The primary goal of this study is to observe how complex the behaviors of Cepheids can be, and to show how the continued monitoring of Cepheids at multiple wavelengths can begin to reveal their "secret lives." We aim to achieve this through optical photometry, UV spectroscopy and X-ray imaging. Through Villanova's guaranteed access to ground-based telescopes, we have secured well-covered light curves as regularly as possible. Amplitudes and times of max brightness were obtained and compared to previous literature results. At UV wavelengths, we have secured hi-res spectra of 2 nearby Cepheids -…
Ultra-luminous X-ray pulsars (ULXPs) provide a unique opportunity to study super-Eddington accretion. We present the results of a monitoring campaign of ULXP NGC 7793 P13. Over our four-year monitoring campaign with Swift, XMM-Newton, and NuSTAR, we measured a continuous spin-up with $\dot P$ ~ -3.8e-11 s/s. The strength of the spin-up is independent of the observed X-ray flux, indicating that despite a drop in observed flux in 2019, accretion onto the source has continued at largely similar rates. The source entered an apparent off-state in early 2020, which might have resulted in a change in…
Obscuring winds driven away from active supermassive black holes are rarely seen due to their transient nature. They have been observed with multi-wavelength observations in a few Seyfert 1 galaxies and one broad absorption line radio-quiet quasar so far. An X-ray obscuration event in MR 2251-178 was caught in late 2020, which triggered multi-wavelength (NIR to X-ray) observations targeting this radio-quiet quasar. In the X-ray band, the obscurer leads to a flux drop in the soft X-ray band from late 2020 to early 2021. X-ray obscuration events might have a quasi-period of two decades consideri…
(Abridged) Active galactic nuclei show a wealth of interesting physical processes, some of which are poorly understood. We want to address a number of open questions, including the location and physics of the outflow from AGN, the nature of the continuum emission, the geometry and physical state of the X-ray broad emission line region, the Fe-K line complex, the metal abundances of the nucleus and finally the interstellar medium of our own Galaxy. We study one of the best targets for these aims, the Seyfert 1 galaxy Mrk 509 with a multiwavelength campaign using five satellites (XMM-Newton, INT…
In this paper we present a temporal and spectral analysis of X-ray data from the XMM and Chandra observations of the ultrasoft and variable Seyfert galaxy RX J1301.9+2747. In both observations the source clearly displays two distinct states in the X-ray band, a long quiescent state and a short flare (or eruptive) state which differs in count rates by a factor of 5--7. The transition from quiescent to flare state occurs in 1--2 ks. We have observed that the quiescent state spectrum is unprecedentedly steep with a photon index Gamma~7.1, and the spectrum of the flare state is flatter with Gamma~…
