PSPC Data Research Articles

Is There an Enormous Cold Front at the Virial Radius of the Perseus Cluster?

Abstract We present new XMM-Newton observations extending the mosaic of the Perseus cluster out to the virial radius to the west. Previous studies with ROSAT have reported a large excess in surface brightness to the west, possibly the result of large-scale gas sloshing. In our new XMM-Newton observations we have found two X-ray surface brightness edges at 1.2 and 1.7 Mpc to the west. The temperature measurements obtained with Suzaku data indicate that the temperature increases sharply at each edge, consistent with what would be expected from cold fronts. However the the XMM-Newton data are affected by stray light, which at present is a poorly understood source of systematic error that can also lead to curved features in X-ray images. To test our results, we compared our X-ray surface brightness profile with that obtained from ROSAT PSPC data. While the edge at 1.2 Mpc is confirmed by ROSAT PSPC, the ROSAT data quality is insufficient to confirm the outer edge at 1.7 Mpc. Further observations with future X-ray telescopes will be needed to confirm the existence of the outer edge at 1.7 Mpc. By comparing with numerical simulations, we find that these large cold fronts require a large impact parameter, and low-mass ratio mergers that can produce fast gas motions without destroying the cluster core.

Multifrequency study of the Large Magellanic Cloud supernova remnant J0529−6653 near pulsar B0529-66

We report the ATCA and ROSAT detection of Supernova Remnant (SNR) J0529--6653 in the Large Magellanic Cloud (LMC) which is positioned in the projected vicinity of the known radio pulsar PSR B0529-66. In the radio-continuum frequencies, this LMC object follows a typical SNR structure of a shell morphology with brightened regions in the south-west. It exhibits an almost circular shape of D=33 x 31 pc (1 pc uncertainty in each direction) and radio spectral index of alpha=-0.68$+-$0.03 - typical for mid-age SNRs. We also report detection of polarised regions with a peak value of 17+-7% at 6 cm. An investigation of ROSAT images produced from merged PSPC data reveals the presence of extended X-ray emission coincident with the radio emission of the SNR. In X-rays, the brightest part is in the north-east. We discuss various scenarios in regards to the SNR-PSR association with emphasis on the large age difference, lack of a pulsar trail and no prominent point-like radio or X-ray source.

An X‐Ray Survey of Wolf‐Rayet Stars in the Magellanic Clouds. II. TheROSATPSPC and HRI Data Sets

Wolf-Rayet (WR) stars in the Magellanic Clouds (MCs) are ideal for studying the production of X-ray emission by their strong fast stellar winds. We have started a systematic survey for X-ray emission from WR stars in the MCs using archival Chandra, ROSAT, and XMM-Newton observations. In Paper I, we reported the detection of X-ray emission from 29 WR stars using Chandra ACIS observations of 70 WR stars in the MCs. In this paper, we report the search and analysis of archival ROSAT PSPC and HRI observations of WR stars. While useful ROSAT observations are available for 117 WR stars in the MCs, X-ray emission is detected from only seven of them. The detection rate of X-ray emission from MCs WR stars in the ROSAT survey is much smaller than in the Chandra ACIS survey, illustrating the necessity of high angular resolution and sensitivity. LMC-WR 101-102 and 116 were detected by both ROSAT and Chandra, but no large long-term variations are evident.

The Darkest Bright Star:ChandraX‐Ray Observations of Vega

We present X-ray observations of Vega obtained with the Chandra High Resolution Camera and Advanced CCD Imaging Spectrometer. After a total of 29 ks of observation with Chandra, X-rays from Vega remain undetected. We derive upper limits to the X-ray luminosity of Vega as a function of temperature over the range of 105-107 K and find a 99.7% upper limit as low as ~2 × 1025 ergs s-1 at T = 106.2 K. We also compare these new deeper observations with the limit derived from a reanalysis of ROSAT PSPC data. Our X-ray luminosity limit for Vega is still greater than predictions of post-Herbig Ae phase X-rays from the shear dynamo model proposed by Tout & Pringle for a Vega age of 350 Myr. If the age of Vega is closer to 100 Myr, as suggested by some indicators, our X-ray limit is then similar to Tout-Pringle model predictions. Current X-ray observations of Vega are therefore unable to discriminate between different scenarios explaining the X-ray activity of the convectively stable Herbig Ae/Be stars. Further progress is more likely to be achieved through X-ray observations of younger main-sequence early-type A stars, whose conjectured residual post-Herbig Ae phase X-ray activity would be significantly higher.

Markarian 1239: A Highly Polarized Narrow-Line Seyfert 1 Galaxy with a Steep X-Ray Spectrum and Strong NeixEmission

We report the results of an XMM-Newton observation of the narrow-line Seyfert 1 galaxy Mrk 1239. This optically highly polarized AGN has one of the steepest X-ray spectra found in AGNs, with αX = +3.0 based on ROSAT PSPC data. The XMM-Newton EPIC pn and MOS data confirm this steep X-ray spectrum. The pn data are best fitted by a power law with a partial-covering absorption model suggesting two light paths between the continuum source and the observer, one indirect scattered one, which is less absorbed, and a highly absorbed direct light path. This result agrees with the wavelength-dependent degree of polarization in the optical/UV band. Residuals in the X-ray spectra of all three XMM-Newton EPIC detectors around 0.9 keV suggest the presence of an emission-line feature, most likely the Ne IX triplet. The detection of Ne IX and the nondetection of O VII/O VIII suggest a supersolar Ne/O ratio.

A multiband study of Hercules A - I.ROSATobservations of the intracluster medium

We have made ROSAT PSPC and HRI X-ray observations to study the intracluster gas surrounding the powerful radio source Hercules A. The cluster is luminous in X-rays (Lbol = 4.8 × 10 37 W), although apparently poor in optical galaxies, and the host of the radio source is the central dominating galaxy of the cluster. The azimuthally-averaged X-ray surface brightness profile is well fitted by a modified King (�) model, with core radius rc = 121 ± 10 kpc and � = 0.74 ± 0.03, but the cluster is elongated parallel to the radio source, especially on the scale of the radio lobes, and fits to individual quadrants give a core radius 50 per cent larger along the radio axis. Part of this elongation appears to be associated with enhanced X-ray emission superimposed on the outer radio lobes, which extend to just over 2rc. There are no obvious depressions in the X-ray emission coincident with the radio lobes, as expected if the relativistic plasma displaces the ICM. However, we show that these depressions may be quite weak, essentially because the main part of the lobes are outside the cluster core. From the surface brightness profile for the PSPC data the X-ray emission extends out to � 2.2 Mpc radius. In the absence of the powerful jets (which must be a transient phenomenon on cosmological timescales), we would expect a cooling flow at the centre of the cluster; but currently it must be substantially disturbed by the expansion of the radio lobes. The PSPC spectrum reveals a cool component of the ICM with 0.5 <kT <1 keV in addition to the � 4 keV component detected by ASCA and BeppoSAX. The central cooling time could be as low as 2 Gyr if the cool component is centrally concentrated, otherwise it is around 6 Gyr. Cooling is significant on a Hubble time to a radius of about 90 kpc. The modelled central electron density of n0 = 1.0 × 10 4 m 3 is typical for modest cooling flows. Finally, we have detected faint X-ray emission from a compact central source, with size < 15 kpc and luminosity � 2 × 10 36 W.

The hot and cool component of the symbiotic nova SMC 3

The ~6 year supersoft X-ray lightcurve of the symbiotic nova SMC 3 (=RX J0048.4-7332) in the Small Magellanic Cloud is derived from archival ROSAT PSPC and HRI data. It shows one deep X-ray eclipse during which the count rate decreased by a factor of $\ga$80. In MACHO B -band data sinusoidal variation is found with a quasi-periodicity of ~4 years. The minimum of the B -band flux occurs during the X-ray eclipse. In OGLE II I -band observations performed after the ROSAT observations we detect $110\pm2$ day oscillations which we interpret as pulsations of the M0 giant star in the symbiotic system. The observed duration of the supersoft X-ray eclipse of ~0.4–1.8 years is explained by the occultation of the white dwarf by the giant companion with an orbital period of ~(4.0–4.8) years and a strong wind blown from its surface with a mass loss rate of ~$(2.6{-}8.2)\times 10 ^{-7} {M}_{\odot} {\rm yr^{-1}}$, assuming that ~$(1{-}3.5)\%$ of the ionized phase is neutral (e.g. due to dust) and assuming a terminal velocity of ~$30 {\rm km} {\rm s^{-1}}$. The ~4 year quasi-periodicity found in the optical is explained as the binary orbital period of the system. It is less likely that it reflects the activity (or mass-loss) time scale of the red giant star. A ~(700–800) day quasi-periodicity found in the OGLE II and MACHO data is explained as the first harmonic of a binary orbital cycle. SMC 3 therefore may be classified as a small-amplitude red variable star (SARV). The hot star most likely is in a state of steady nuclear burning with an accretion rate somewhat below the upper critical value of ~$10^{-7} {M}_{\odot} {\rm yr}^{-1}$.

ChandraObservation of 3C 212: A New Look at the X‐Ray and Ultraviolet Absorbers

The red quasar 3C 212 (z = 1.049) is one of the most distant and most luminous active galactic nuclei that have shown evidence of an X-ray warm absorber. In order to further investigate this unusual quasar, we used Chandra/ACIS-S to observe 3C 212 for 19.5 ks, resulting in a net detection of ~4000 counts. The Chandra data confirm the presence of an excess absorbing column NH ≈ 4 × 1021 cm-2 at the quasar redshift, but we find no compelling evidence for a warm absorber. Using both the Chandra and archival ROSAT PSPC data, we obtain very good fits for both a partially covered neutral absorber and a low-ionization (U = 0.03) photoionized absorber. In the ultraviolet, 3C 212 shows a strong associated Mg II absorber. Based on a moderate-resolution (80 km s-1) MMT spectrum we show that the absorber is highly saturated and has a covering fraction less than 60%, implying that the absorber is truly intrinsic to the quasar. Photoionization modeling of the Mg II absorber yields a constraint on the ionization parameter of U < 0.03, inconsistent with a warm UV/X-ray absorber. In addition to our spectral analysis, we find evidence in the ACIS image data for weak extended emission surrounding the quasar as well as emission corresponding to the radio lobes at a distance of 5'' from 3C 212. The statistical significance of these features is low, but we briefly explore the implications if the detections are valid.

X-ray bright groups and their galaxies

Combining X-ray data from the ROSAT PSPC and optical data drawn from the literature, we examine in detail the relationship between the X-ray and optical properties of X-ray bright galaxy groups. We find a relationship between optical luminosity and X-ray temperature consistent with that expected from self-similar scaling of galaxy systems, L_B \propto T^{1.6 +/- 0.2}. The self-similar form and continuity of the L_B : T relation from clusters to groups and the limited scatter seen in this relation, implies that the star formation efficiency is rather similar in all these systems. We find that the bright extended X-ray components associated with many central galaxies in groups appear to be more closely related to the group than the galaxy itself, and we suggest that these are group cooling flows rather than galaxy halos. In addition we find that the optical light in these groups appears to be more centrally concentrated than the light in clusters. We also use the optical and X-ray data to investigate whether early or late type galaxies are primarily responsible for preheating in groups. Using three different methods, we conclude that spiral galaxies appear to play a comparable role to early types in the preheating of the intragroup medium. This tends to favour models in which the preheating arises primarily from galaxy winds rather than AGN, and implies that spirals have played a significant role in the metal enrichment of the intragroup medium.

ROSATHRI Investigation of the NGC 507 X‐Ray Halo

We present an X-ray investigation of the elliptical galaxy NGC 507. We make use of archival Rosat HRI, PSPC and Chandra data, to connect the large-scale structure of the halo to the core morphology. Our analysis shows that the halo core (r 3 r_e) are characterised by different dynamical properties and suggests a different origin of the two components. The halo core has a complex morphology with a main X-ray emission peak, coincident with the center of the optical galaxy, and several secondary peaks. The spatial and spectral analysis of the central peak shows that this feature is produced by denser hot gas in the galaxy core. Our data support the scenario where the gas is kinetically heated by stellar mass losses. Comparison with previously published studies suggest that the core of X-ray extended galaxies is associated to the stellar distribution and has similar properties to the X-ray halo of compact galaxies. The secondary peaks are due instead to interactions between the radio-emitting plasma and the surrounding ISM. We found that the energy input by the central radio source in the ISM may be large enough to prevent gas from cooling. The total mass profile shows the presence of a dark matter halo extending on cluster scales which is likely to be associated with the whole cluster rather than with NGC 507. This structure is typical of many X-ray bright Early-Type galaxies and may explain the spatial and spectral differences with X-ray compact galaxies largely debated in literature. Finally we discuss the nature of the point sources detected in the HRI FOV.

Hard X-ray timing and spectral properties of PSR B0540-69

We report the hard X-ray properties of the young Crab-like LMC pulsar PSR B0540-69, using archival RXTE PCA (2 - 60 keV) and RXTE HEXTE (15 - 250 keV) data. Making use of the very long effective exposure of 684 ks, we derived a very detailed master pulse profile for energies 2 - 20 keV. We confirm the broad single-pulse shape with a dip in the middle and with a significant fine structure to the left of the dip. For the first time pulse profiles in the 10 - 50 keV energy interval are shown. Remarkably, the coarse pulse shape is stable from the optical up to X-ray energies analogous to the case of the Crab pulsar (PSR B0531+21). The profiles can be described with two Gaussians with a phase separation of ~0.2; the distribution of the ratios between the two components from the optical to the X-ray range is consistent with being flat. Therefore we cannot conclude that the profile consists of two distinct components. We also derived a new total pulsed spectrum in the ~0.01 - 50 keV range in a consistent analysis including also archival ROSAT PSPC (0.01 - 2.5 keV) data. This spectrum cannot be described by a single power-law, but requires an additional energy dependent term. The bending of the spectrum around 10 keV resembles that of the Crab pulsar spectrum. Although model calculations using Outer Gap scenarios could probably explain the high-energy characteristics of PSR B0540-69 as they successfully do for the Crab, our measurements do not entirely agree with the latest calculations by Zhang & Cheng (2000). The small discrepancies are likely to be caused by uncertainties in the pulsar's geometry.

Soft X‐Ray Excess Emission in Clusters of Galaxies Observed withXMM‐Newton

We present results on the spectroscopic analysis of XMM-Newton EPIC data of the central 0.5 h 50 -1 Mpc regions of the clusters of galaxies Coma, A1795 and A3112. A significant warm emission component at a level above the systematic uncertainties is evident in the data and confirmed by ROSAT PSPC data for Coma and A1795. The non-thermal origin of the phenomenon cannot be ruled out at the current level of calibration accuracy, but the thermal model fits the data significantly better, with temperatures in the range of 0.6 – 1.3 keV and electron densities of the order of 10-4 – 10-3 cm-3. In the outer parts of the clusters the properties of the warm component are marginally consistent with the results of recent cosmological simulations, which predict a large fraction of the current epoch’s bayons located in a warm-hot intergalactic medium (WHIM). However, the derived densities are too high in the cluster cores, compared to WHIM simulations, and thus more theoretical work is needed to fully understand the origin of the observed soft X-ray excess.

Long-Term X-Ray Variability of Quasars in the Lockman Hole Field Observed with ROSAT

Abstract An improved method has been utilized to estimate the X-ray power spectral densities (PSD) and the variation time scales of three quasars in the Lockman Hole field. Five archival ROSAT PSPC data covering a two-year range were analyzed. To estimate PSD from sparse and unevenly-sampled lightcurves, a forward-method approach with extensive Monte Carlo simulations was adopted. A broken power-law type PSD with a constant Poisson noise component was assumed with a break frequency, $f_\mathrm{b}$. Then, assuming the PSD slope, $\alpha$, to be $-2 &amp;lt; \alpha &amp;lt;-1, 1/ f_\mathrm{b}$ was constrained as $\gtrsim$ 25 days for one object, while the constraints on the other two objects were very weak. The long-time scale of the one object is consistent with the view that luminous AGNs host massive black holes.

Soft X-ray properties of a high-redshift sample of QSOs observed with ROSAT

In order to study systematically the soft -ray emission of active galactic nuclei (AGNs) at medium to high redshifts, we have analysed ROSAT PSPC and HRI data of QSOs at 0.26 ⩽z⩽ 3.43 selected from the second deepest ROSAT PSPC survey carried out in 1991–1993 by McHardy et al. Our sample of 22 type 1 QSOs is nearly complete above a flux limit of 1.4 × 10−14 erg cm−2 s−1 in the 0.1–2 keV band. Of these, nine QSOs show long-term (∼2 yr) -ray variability by a factor of 1.5–3.5. Significant excess absorption above the Galactic column is seen in three QSOs. The soft -ray photon index of the QSOs ranges from 1.4 to 3.7. Three QSOs have steep soft -ray spectra (ΓX > 3.0), one of which is a narrow-line QSO – a high-luminosity version of narrow-line Seyfert 1 galaxies. The average photon index (〈ΓX〉) is 2.40 ± 0.09 (with a dispersion of 0.57) in the 0.1–2 keV band. The average QSO spectra in four redshift bins flatten from an average photon index of 〈ΓX〉∼ 2.53 at 0.25 ⩽z⩽ 1 to 〈ΓX〉∼ 2 at 2 ⩽z⩽ 3.4. The flattening of the average photon index can be understood in terms of the redshift effect of the mean intrinsic QSO spectrum consisting of two components – a soft -ray excess and a power-law component. We have also studied optical spectra of 12 of the 22 QSOs.

Ultraluminous X-ray source 1E 0953.8+6918 (M81 X-9): an intermediate-mass black hole candidate and its environs

We present a ROSAT and ASCA study of the Einstein source X-9 and its relation to a shock-heated shell-like optical nebula in a tidal arm of the M81 group of interacting galaxies. Our ASCA observation of the source shows a flat and featureless X-ray spectrum well described by a multicolour disc blackbody model. The source most likely represents an optically thick accretion disc around an intermediate-mass black hole (M∼102 M⊙) in its high/soft state, similar to other variable ultraluminous X-ray sources observed in nearby disc galaxies. Using constraints derived from both the innermost stable orbit around a black hole and the Eddington luminosity, we find that the black hole is fast-rotating and that its mass is between ∼80 M⊙–1.5×102 M⊙. The inferred bolometric luminosity of the accretion disc is ∼(1.1×1040 erg s−1)/(cos i). Furthermore, we find that the optical nebula is very energetic and may contain large amounts of hot gas, accounting for a soft X-ray component as indicated by archival ROSAT PSPC data. The nebula is apparently associated with X-9; the latter may be powering the former and/or they could be formed in the same event (e.g. a hypernova). Such a connection, if confirmed, could have strong implications for understanding both the birth of intermediate-mass black holes and the formation of energetic interstellar structures.

DeepROSATHRI Observations of the NGC 1399/NGC 1404 Region: Morphology and Structure of the X‐Ray Halo

We present the analysis of a deep (167 ks) ROSAT HRI observation of the cD galaxy NGC 1399 in the Fornax Cluster, comparing it with previous work on this galaxy and with recent Chandra data. We find, in agreement with previous observations, an extended and asymmetric gaseous halo with a luminosity (in the 0.1-2.4 keV energy band) of LX = (5.50 ± 0.04) × 1041 ergs s-1 within 46 kpc (assuming a distance of D = 19 Mpc). Using both HRI and, at larger radii, archival PSPC data, we find that the radial behavior of the X-ray surface brightness profile is not consistent with a simple β-model and suggests instead three distinct components. We use a multicomponent bidimensional model to study in detail these three components, which we identify respectively with the cooling flow region, the galactic halo, and the cluster halo. From these data we derive a binding mass distribution in agreement with that suggested by optical dynamical indicators, with an inner core dominated by luminous matter and an extended dark halo differently distributed on galactic and cluster scales. The HRI data and a preliminary analysis of Chandra public data allow us to detect significant density fluctuations in the halo. We discuss possible nonequilibrium scenarios to explain the hot halo structure, including tidal interactions with neighboring galaxies, ram stripping from the intracluster medium, and merging events. In the innermost region of NGC 1399, the comparison between the X-ray and radio emission suggests that the radio-emitting plasma is displacing and producing shocks in the hot X-ray-emitting gas. We do not detect the nuclear source in X-rays, and we pose an upper limit of ~4 × 1039 ergs s-1 (0.1-2.4 keV) to its X-ray luminosity. We found that the NGC 1404 halo is well represented by a single symmetric β-model and follows the stellar light profile within the inner 8 kpc. The mass distribution is similar to the "central" component of the NGC 1399 halo. At larger radii, ram pressure stripping from the intracluster gas produces strong asymmetries in the galactic halo. Finally, we discuss the properties of the point-source population, finding evidence of correlation between the source excess and NGC 1399.

CCD Sounding Rocket Observation of the High‐Latitude Soft X‐Ray Background

Results of a charge coupled device (CCD) sounding rocket observation (36.092UH, 1995 May) of the X-ray background between 0.3 and 10 keV are presented. The target for the 36.092UH flight was a high-latitude region of the X-ray background centered at l = 963, b = +481 toward the constellation Draco. CCD spectra obtained from this observation were fitted independently and simultaneously to a PSPC spectrum obtained from a nearby ROSAT field (RP 70137). Above 1 keV, the high-latitude CCD data are well fitted by a single absorbed 9.5E-1.4 power law. Below 1 keV, CCD and PSPC data are fitted equally well by the addition of a cosmic abundance thermal plasma (kT = 0.14 keV) or by a thermal bremstrahhlung component plus an O VII line at 0.574 keV.

X‐Ray Synchrotron Emission from 10–100 TeV Cosmic‐Ray Electrons in the Supernova Remnant SN 1006

We present the results of a joint spectral analysis of RXTE PCA, ASCA SIS, and ROSAT PSPC data of the supernova remnant SN 1006. This work represents the first attempt to model both the thermal and nonthermal X-ray emission over the entire X-ray energy band from 0.12 to 17 key. The thermal flux is described by a nonequilibrium ionization model with an electron temperature kTe = 0.6 key, an ionization timescale n(sub 0)t = 9 x 10(exp 9)/cc s, and a relative elemental abundance of silicon that is 10 - 18 times larger than the solar abundance. The nonthermal X-ray spectrum is described by a broken power law model with low- and high-energy photon indices Gamma(sub 1) = 2.1 and Gamma(sub 2) = 3.0, respectively. Since the nonthermal X-ray spectrum steepens with increasing energy, the results of the present analysis corroborate previous claims that the nonthermal X-ray emission is produced by synchrotron radiation. We argue that the magnetic field strength is significantly larger than previous estimates of about 10 micro G and arbitrarily use a value of 40 micro G to estimate the parameters of the cosmic-ray electron, proton, and helium spectra of the remnant. The results for the ratio of the number densities of protons and electrons (R = 160 at 1 GeV), the total energy in cosmic rays (E(sub cr) = 1 x 10(exp 50) ergs), and the spectral index of the electrons at 1 GeV (Gamma(sub e) = 2.14 +/- 0.12) are consistent with the hypothesis that Galactic cosmic rays are accelerated predominantly in the shocks of supernova remnants. Yet, the remnant may or may not accelerate nuclei to energies as high as the energy of the knee, depending on the reason why the maximum energy of the electrons is only 10 TeV.

The Soft X-Ray Properties of Nearby Low-Luminosity Active Galactic Nuclei and their Contribution to the Cosmic X-Ray Background

We have examined ROSAT soft X-ray observations of a complete, distance-limited sample of Seyfert and LINER galaxies. X-ray data are available for 46 out of 60 such objects which lie within a hemisphere of radius 18 Mpc. We have constructed radial profiles of the nuclear sources in order to characterize their spatial extent and, in some cases, to help constrain the amount of flux associated with a nuclear point source. PSPC data from ROSAT have been used to explore the spectral characteristics of the objects with sufficient numbers of detected counts. Based on the typical spectral parameters of these sources, we have estimated the luminosities of the weaker sources in the sample. We then explore the relationship between the soft X-ray and Hα luminosities of the observed objects; these quantities are correlated for higher luminosity AGNs. We find a weak correlation at low luminosities as well, and we have used this relationship to predict LX for the 14 objects in our sample that lack X-ray data. Using the results of the spatial and spectral analyses, we have compared the X-ray properties of Seyferts and LINERs, finding no striking differences between the two classes of objects. However, both types of objects often exhibit significant amounts of extended emission, which could minimize the appearance of differences in their nuclear properties. The soft X-ray characteristics of the type 1 and type 2 active galaxies in the sample are also discussed. We then compute the local X-ray volume emissivity of low-luminosity Seyferts and LINERs and investigate their contribution to the cosmic X-ray background. The 0.5–2.0 keV volume emissivity of 2.2 × 1038 ergs s-1 Mpc-3 we obtain for our sample suggests that low-luminosity AGNs produce at least 9% of the soft X-ray background.

Discovery of pulsations from the Be/X-ray binary RXJ0101.3-7211 in the SMC by XMM-Newton

We report pulsations in the X-ray flux of RX J0101.3 7211 in the Small Magellanic Cloud (SMC) with ap eriod of (455 2) s in XMM-Newton EPIC-PN data. The X-ray spectrum can be described by a power-law with a photon index of 0:6 0:1. Timing analysis of ROSAT PSPC and HRI archival data conrms the pulsations and indicates a period increase of 5 s since 1993. RX J0101.3 7211 varied in brightness during the ROSAT observations with timescales of years with a maximum unabsorbed flux of 6 10 13 erg cm 2 s 1 (0.1{2.4 keV). The flux during the XMM-Newton observation in the ROSAT band was lower than during the faintest ROSAT detection. The unabsorbed luminosity derived from the EPIC-PN spectrum is 2 10 35 erg s 1 (0.2{10.0 keV) assuming a distance of 60 kpc. Optical spectra of the proposed counterpart taken at the 2.3 m telescope of MSSSO in Australia in August 2000 show strong H emission and indicate a Be star. The X-ray and optical data conrm RX J0101.3 7211 as a Be/X-ray binary pulsar in the SMC.