scholarly journals X-Ray and Optical Observations of a New X-Ray Soft Intermediate Polar: RX J0512.2–3241

1997 ◽  
Vol 163 ◽  
pp. 689-689
Author(s):  
V. Burwitz ◽  
K. Reinsch ◽  
K. Beuermann ◽  
H.-C. Thomas
Keyword(s):  
Optical Observations ◽  
Galactic Latitude ◽  
Ccd Photometry ◽  
X Ray ◽  
Probable Spin ◽  
Sky Survey ◽  
Intermediate Polars ◽  
Orbital Periods ◽  
Low Magnetic Field

The V~17.6 mag optical counterpart of the bright, soft, high-galactic latitude X-ray source RX J0512.2–3241 detected during the ROSAT All-Sky Survey, has been identified as a new, asynchronously rotating, magnetic cataclysmic variable (intermediate polar). The X-ray spectrum of RXJ0512–32 is similar to that of polars, it shows a soft component with no intrinsic absorption and a blackbody temperature kTbb~38 eV. From our optical follow-up B and V CCD photometry (cf. Fig. 1) we derive most probable spin and orbital periods of (863.5 ± 0.7) s and (3.45 ± 0.03) h respectively. A lower limit for the distance to the system is d > 740 pc. From this evidence we suggest that RXJ0512-32 is a further member of the ROSAT discovered class of soft X-ray intermediate polars (for details see Burwitz et al., 1996, A&A 310, L25). This still small class of systems (see Haberl and Motch 1995, A&A 297, L37) has X-ray characteristics similar to those of low magnetic field polars and may be their long sought evolutionary progenitors.

scholarly journals Identification of a Complete Sample of Northern Rosat All-Sky Survey X-Ray Sources

1998 ◽  
Vol 179 ◽  
pp. 449-449
Author(s):  
J. Krautter ◽  
I. Thiering ◽  
F.-J Zickgraf ◽  
I. Appenzeller ◽  
R. Kneer ◽  
...  
Keyword(s):  
Optical Observations ◽  
Limited Sample ◽  
Ccd Imaging ◽  
X Ray ◽  
The North ◽  
Cluster Of Galaxies ◽  
Faint Object ◽  
Sky Survey ◽  
Faint Object Spectrograph ◽  
North Galactic

We present results of the optical identification of a spatially complete, flux limited sample of about 700 ROSAT All-Sky X-ray sources contained in 6 study areas north of δ = −9° with |bII|> 20° (including one region near the North Galactic pole (NGP), another one near the North Ecliptic pole (NEP)). Countrate limits are 0.01 cts s–1 near the NEP and 0.03 cts s–1 for the other areas. The optical observations were performed at the 2.15-m telescope of the Guillermo Haro Observatory, Mexico, using the Landessterwarte Faint Object Spectrograph Camera which allows to carry out direct CCD imaging and multi-object spectroscopy. The limiting magnitude is about 19m for spectroscopy and about 23m for B and R direct imaging. Our analysis shows a dependency of the ratio of ‘extragalactic’ (e.g., AGN, cluster of galaxies) to ‘stellar’ (e.g., coronal emitters, active binaries) counterparts on NH. In the area near the NGP (low NH) ‘extragalactic’ counterparts dominate, while in the area with the highest NH ‘stellar’ counterparts dominate.

scholarly journals EROSITA: AGN SCIENCE, BACKGROUND DETERMINATION, AND OPTICAL FOLLOW-UP SPECTROSCOPY

2013 ◽  
Vol 53 (A) ◽  
pp. 793-798
Author(s):  
Thomas Boller
Keyword(s):  
Small Sample ◽  
Scientific Success ◽  
X Ray ◽  
Photometric Redshift ◽  
Sky Survey ◽  
Extended Sources ◽  
Small Sample Sizes ◽  
Primary Instrument ◽  
The Ideal

More than 20 years after the highly impacting ROSAT all-sky survey in the soft X-ray spectral range, we are close to the next major X-ray all/sky surveys with eROSITA. eROSITA will be the primary instrument on-board the Russian “Spectrum–Roentgen–Gamma” (SRG) satellite which will be launched from Baikonur in 2014 and placed in an L2 orbit. It will perform the first imaging all-sky survey in the medium energy X-ray range up to 10 keV with an unprecedented spectral and angular resolution. The eROSITA all sky X-ray survey will take place in a very different context than the ROSAT survey. There is now a wealth of complete, ongoing and planned surveys of the sky in broad range of wavelengths from the gamma, X-ray to the radio. A significant amount of science can be accomplished through the multi-frequency study of the eROSITA AGN and cluster sample, including optical confirmation and photometric redshift estimation of the eROSITA extended sources and AGNs. Optical spectroscopy has been, and will for the foreseeable future be, one of the main tools of astrophysics allowing studies of a large variety of astronomical objects over many fields of research. The fully capitalize on the eROSITA potential, a dedicated spectroscopic follow-up program is needed. 4MOST is the ideal instrument to secure the scientific success of the eROSITA X-ray survey and to overcome the small sample sizes together with selection biases that plagued past samples. The aim is to have the instrument commissioned in 2017, well matched to the data releases of eROSITA and Gaia. The design and implementation of the 4MOST facility simulator aimed to optimize the science output for eROSITA is described in necessary details.

scholarly journals X-ray observations of the nova shell IPHASX J210204.7+471015*

2021 ◽  
Author(s):  
J A Toalá ◽  
G Rubio ◽  
E Santamaría ◽  
M A Guerrero ◽  
S Estrada-Dorado ◽  
...  
Keyword(s):  
Time Series ◽  
Binary System ◽  
Binary Star ◽  
Optical Observations ◽  
X Ray ◽  
Imaging Camera ◽  
Nova Shells ◽  
Intermediate Polars ◽  
Time Series Analyses ◽  
Nova Shell

Abstract We present the analysis of XMM-Newton European Photon Imaging Camera (EPIC) observations of the nova shell IPHASX J210204.7+471015. We detect X-ray emission from the progenitor binary star with properties that resemble those of underluminous intermediate polars such as DQ Her: an X-ray-emitting plasma with temperature of TX = (6.4 ± 3.1) × 106 K, a non-thermal X-ray component, and an estimated X-ray luminosity of LX = 1030 erg s−1. Time series analyses unveil the presence of two periods, the dominant with a period of 2.9 ± 0.2 hr, which might be attributed to the spin of the white dwarf, and a secondary of 4.5 ± 0.6 hr that is in line with the orbital period of the binary system derived from optical observations. We do not detect extended X-ray emission as in other nova shells probably due to its relatively old age (130–170 yr) or to its asymmetric disrupted morphology which is suggestive of explosion scenarios different to the symmetric ones assumed in available numerical simulations of nova explosions.

scholarly journals The AGN Content of Hard X-ray Surveys

2002 ◽  
Vol 184 ◽  
pp. 235-244 ◽  
Author(s):  
Andrea Comastri ◽  
Cristian Vignali ◽  
Marcella Brusa
Keyword(s):  
Optical Properties ◽  
Optical Observations ◽  
X Ray ◽  
Normal Galaxies ◽  
X Ray Background ◽  
X Ray Absorption ◽  
Multiwavelength Observations

AbstractMultiwavelength observations of the hard X-ray selected sources discovered by BeppoSAX, Chandra and XMM-Newton surveys have significantly improved our knowledge of the AGN population. The increasing number of X-ray obscured AGN so far discovered confirms the prediction of those AGN synthesis models for the X-ray background based on the Unified scheme. However, follow-up optical observations of hard X-ray selected sources indicate that their optical properties are quite varied and the simple relations between optical and X-ray absorption are by no means without exception. Moreover there is evidence of a substantial number of luminous X-ray sources hosted by apparently normal galaxies. In this paper the results obtained from multiwavelength observations of hard X-ray selected sources discovered by BeppoSAX and XMM-Newton are presented and briefly discussed.

scholarly journals A Search for the Signature of the Diffuse Soft X-ray Background in the ROSAT Wide-Field Camera All-Sky Survey

1996 ◽  
Vol 152 ◽  
pp. 289-293
Author(s):  
R.G. West ◽  
R. Willingale ◽  
J.P. Pye ◽  
T.J. Sumner
Keyword(s):  
Charged Particles ◽  
Field Of View ◽  
Wide Field ◽  
Galactic Latitude ◽  
The Sun ◽  
X Ray ◽  
Cosmic Background ◽  
Sky Survey ◽  
Cosmic Abundance ◽  
X Ray Background

We present the results of an attempt to locate the signature of the diffuse soft X-ray background in the ROSAT Wide-Field Camera (WFC) all-sky survey. After removal of non-cosmic background sources (eg. energetic charged particles), the field-of-view integrated count rate in the WFC S1a filter (90–185 eV) shows no consistent variation with Galactic latitude or longitude. We place limits on the signal from the soft X-ray background (SXRB) in the WFC, and show that these limits conflict with the observations of the Wisconsin Sky Survey if the SXRB in this energy range is assumed to be produced by a thermal plasma of cosmic abundance and a temperature T ~ 106 K within d ~ 100 pc of the Sun.

scholarly journals ASCA Sky Survey Observations and the Cosmic X-Ray Background in 2-10 KeV

1998 ◽  
Vol 188 ◽  
pp. 197-200
Author(s):  
H. Inoue ◽  
T. Takahashi ◽  
Y. Ueda ◽  
A. Yamashita ◽  
Y. Ishisaki ◽  
...  
Keyword(s):  
Energy Range ◽  
Galactic Plane ◽  
Galactic Latitude ◽  
High Galactic Latitude ◽  
X Ray ◽  
Sky Survey ◽  
X Ray Background ◽  
Excess Component ◽  
Highly Uniform

The X-ray background in the energy range above 2 keV is highly uniform except for an excess component along the Galactic plane. The excess along the plane is considered to be associated with our Galaxy, whereas the rest of the emission is believed to be of extragalactic origin. In this paper, the X-ray background at high Galactic latitude is discussed and is designated as the CXB (cosmic X-ray background) to distinguish it from the Galactic origin.

scholarly journals XMM-Newton observations of eleven intermediate polars and possible candidates

2020 ◽  
Vol 639 ◽  
pp. A17
Author(s):  
H. Worpel ◽  
A. D. Schwope ◽  
I. Traulsen ◽  
K. Mukai ◽  
S. Ok
Keyword(s):  
Optical Data ◽  
Plasma Emission ◽  
Short Term ◽  
X Ray ◽  
Hot Plasma ◽  
Intermediate Polars ◽  
Orbital Periods ◽  
Firm Evidence ◽  
Short Term Variability

Aims. We aim to identify new intermediate polars (IPs) in XMM-Newton observations from a list of promising candidates. By selecting targets not previously known to be X-ray bright, we aim to uncover evidence for an X-ray underluminous IP subpopulation. Methods. We performed period searches on the XMM-Newton X-ray and optical data of our targets to seek both the spin and orbital periods, which differ in IPs. We also investigated the X-ray spectra to find the hot plasma emission shown by these objects. With archival Swift data we coarsely investigated the long-term X-ray variability, and with archival optical data from a variety of catalogues, we compared the optical to X-ray luminosity to identify X-ray faint objects. This paper presents the first XMM-Newton observation of the prototype IP, DQ Her. Results. We find firm evidence for HZ Pup, V349 Aqr, and IGR J18151-1052 being IPs, with likely white dwarf spin periods of 1552, 390, and 390 s, respectively. The former two have luminosities typical of IPs, and the latter is strongly absorbed and with unknown distance. GI Mon and V1084 Her are apparently non-magnetic CVs with interesting short-term variability unrelated to WD spin. V533 Her is probably a magnetic CV and remains a good IP candidate, while V1039 Cen is possibly a polar. The remaining candidates were too faint to allow for any firm conclusions.

scholarly journals A New PG 1159-Type Central Star Discovered in the ROSAT XRT All Sky Survey: Non-LTE Analysis of X-Ray and Optical Spectra

1993 ◽  
Vol 155 ◽  
pp. 496-496
Author(s):  
K. Werner ◽  
C. Motch ◽  
M. Pakull
Keyword(s):  
Surface Brightness ◽  
Central Star ◽  
Model Atmosphere ◽  
Complete Agreement ◽  
Atmospheric Parameters ◽  
Low Gravity ◽  
X Ray ◽  
Sky Survey ◽  
Optical Wavelengths

We report on the discovery of a new PG 1159 star in the ROSAT XRT all sky survey and give results of a model atmosphere analysis. The X-ray source RX J2117.1+3412 is relatively faint (0.33 cnts−1) and extremely soft. Ground based optical follow-up spectroscopy (OHP, France) proofs its PG 1159 nature: It belongs to the “low gravity emission” spectral subtype. Optically, it is the second brightest PG1159 star. CCD [O III] imagery reveals that the star is surrounded by an old arc-shaped planetary nebula of faint surface brightness. The spectral analysis of the central star was performed with non-LTE line blanketed model atmospheres (Werner 1992). We find a complete agreement between the atmospheric parameters determined at optical wavelengths and in the ROSAT PSPC energy range.

Optical Follow-Up Observations of the ASCA Large Sky Survey

1998 ◽  
Vol 188 ◽  
pp. 465-466
Author(s):  
M. Akiyama ◽  
K. Ohta ◽  
T. Yamada ◽  
Y. Ueda ◽  
T. Takahashi ◽  
...  
Keyword(s):  
Clusters Of Galaxies ◽  
X Ray ◽  
Sigma Level ◽  
Sky Survey ◽  
X Ray Background ◽  
Band Survey

To reveal the origin of the cosmic X-ray background (CXB) in the hard band, we are now conducting a wide (~ 7 deg2) and deep (~ 1 × 10−13 erg sec−1 cm−2 in the 2-10 keV band) survey with the ASCA (the ASCA Large Sky Survey, hereafter LSS). We have detected 83 sources above 4 sigma level in the 0.7-10 keV band with the GIS and resolved ~30% of the CXB in the 2-10 keV band into discrete sources (Ueda 1996). AGNs (type 1 and type 2) and clusters of galaxies are expected to be major contributers to these X-ray sources.

scholarly journals Hoinga: a supernova remnant discovered in the SRG/eROSITA All-Sky Survey eRASS1

2021 ◽  
Vol 648 ◽  
pp. A30
Author(s):  
W. Becker ◽  
N. Hurley-Walker ◽  
Ch. Weinberger ◽  
L. Nicastro ◽  
M. G. F. Mayer ◽  
...  
Keyword(s):  
Supernova Remnants ◽  
Galactic Plane ◽  
Point Sources ◽  
Galactic Latitude ◽  
Gas Temperature ◽  
High Galactic Latitude ◽  
X Ray ◽  
Flux Limit ◽  
Sky Survey ◽  
The Universe

Supernova remnants (SNRs) are observable for about (6−15) × 104 yr before they fade into the Galactic interstellar medium. With a Galactic supernova rate of approximately two per century, we can expect to have of the order of 1200 SNRs in our Galaxy. However, only about 300 of them are known to date, with the majority having been discovered in Galactic plane radio surveys. Given that these SNRs represent the brightest tail of the distribution and are mostly located close to the plane, they are not representative of the complete sample. The launch of the Russian-German observatory SRG/eROSITA in July 2019 brought a promising new opportunity to explore the Universe. Here we report findings from the search for new SNRs in the eROSITA all-sky survey data which led to the detection of one of the largest SNRs discovered at wavelengths other than the radio: G249.5+24.5. This source is located at a relatively high Galactic latitude, where SNRs are not usually expected to be found. The remnant, ‘Hoinga’, has a diameter of about 4. °4 and shows a circular shaped morphology with diffuse X-ray emission filling almost the entire remnant. Spectral analysis of the remnant emission reveals that an APEC spectrum from collisionally ionised diffuse gas and a plane-parallel shock plasma model with non-equilibrium ionisation are both able to provide an adequate description of the data, suggesting a gas temperature of the order of kT = 0.1−0.02+0.02 keV and an absorbing column density of NH = 3.6−0.6+0.7 × 1020 cm−2. Various X-ray point sources are found to be located within the remnant boundary but none seem to be associated with the remnant itself. Subsequent searches for a radio counterpart of the Hoinga remnant identified its radio emission in archival data from the Continuum HI Parkes All-Sky Survey and the 408-MHz ‘Haslam’ all-sky survey. The radio spectral index α = −0.69 ± 0.08 obtained from these data definitely confirms the SNR nature of Hoinga. We also analysed INTEGRAL SPI data for fingerprints of 44Ti emission, which is an ideal candidate with which to study nucleosynthesis imprinting in young SNRs. Although no 44Ti emission from Hoinga was detected, we were able to set a 3σ upper flux limit of 9.2 × 10−5 ph cm−2 s−1. From its size and X-ray and radio spectral properties we conclude that Hoinga is a middle-aged Vela-like SNR located at a distance of about twice that of the Vela SNR, i.e. at ~500 pc.

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