- ID:
- ivo://CDS.VizieR/J/A+A/434/483
- Title:
- An XMM-Newton survey of M 31
- Short Name:
- J/A+A/434/483
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- In an analysis of XMM archival observations of the bright Local Group spiral galaxy M 31 we study the population of X-ray sources (X-ray binaries, supernova remnants) down to a 0.2-4.5keV luminosity of 4.4x10^34^erg/s. EPIC hardness ratios and optical and radio information are used to distinguish between different source classes. The survey detects 856 sources in an area of 1.24 square degrees. We correlate our sources with earlier M 31 X-ray catalogues and use information from optical, infra-red and radio wavelengths. As sources within M 31 we detect 21 supernova remnants (SNR) and 23 SNR candidates, 18 supersoft source (SSS) candidates, 7 X-ray binaries (XRBs) and 9 XRB candidates, as well as 27 globular cluster sources (GlC) and 10 GlC candidates, which most likely are low mass XRBs within the GlC. Comparison to earlier X-ray surveys reveal transients not detected with XMM-Newton, which add to the number of M 31 XRBs. There are 567 sources classified as hard, which may either be XRBs or Crab-like SNRs in M 31 or background AGN. The number of 44 SNRs and candidates more than doubles the X-ray-detected SNRs. 22 sources are new SNR candidates in M 31 based on X-ray selection criteria. Another SNR candidate may be the first plerion detected outside the Galaxy and the Magellanic Clouds. On the other hand, six sources are foreground stars and 90 foreground star candidates, one is a BL Lac-type active galactic nucleus (AGN) and 36 are AGN candidates, one source coincides with the Local Group galaxy M 32, one with a background galaxy cluster (GCl) and another is a GCl candidate, all sources not connected to M31.
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Search Results
- ID:
- ivo://CDS.VizieR/J/MNRAS/357/401
- Title:
- An XMM-Newton view of M101
- Short Name:
- J/MNRAS/357/401
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present the global X-ray properties of the point source population in the grand-design spiral galaxy M101, as seen with XMM-Newton. 108 X-ray sources are detected within the D25 ellipse of M101, of which ~24 are estimated to be background galaxies. Multiwavelength cross-correlations show that 20 sources are coincident with H II regions and/or supernova remnants (SNRs), seven have identified/candidate background galaxy counterparts, six are coincident with foreground stars and one has a radio counterpart.
- ID:
- ivo://CDS.VizieR/J/ApJS/80/531
- Title:
- An X-ray catalog and atlas of galaxies.
- Short Name:
- J/ApJS/80/531
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- An X-ray catalog and atlas of galaxies observed with the Einstein Observatory imaging instruments (IPC and HRI) are presented. The catalog comprises 493 galaxies, including targets of pointed observations, and RSA or RC2 galaxies serendipitously included in Einstein fields. A total of 450 of these galaxies were imaged well within the instrumental fields, resulting in 238 detections and 2123 sigma upper limits. The other galaxies were either at the edge of the visible field of view or confused with other X-ray sources. For these a rough measure of their X-ray emission is also given. The atlas shows X-ray contour maps of detected galaxies superposed on optical photographs and gives azimuthally averaged surface brightness profiles of galaxies detected with a high signal-to-noise ratio.
- ID:
- ivo://CDS.VizieR/J/ApJ/511/595
- Title:
- An X-Ray Survey of Galaxies in Pairs
- Short Name:
- J/ApJ/511/595
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Results are reported from the first survey of X-ray emission from galaxies in pairs. The sample consists of 52 pairs of galaxies from the Catalog of Paired Galaxies (Cat. <VII/77>) whose coordinates overlap the ROSAT Position Sensitive Proportional Counter pointed observations. The mean observed log(L_x_) for early-type pairs is 41.35+/-0.21, while the mean log(L_x_) predicted using the (L_X_-L_b_) relationship for isolated early-type galaxies is 42.10+/-0.19. With 95% confidence, the galaxies in pairs are underluminous in the X-ray, compared with isolated galaxies, for the same L_b_. A significant fraction of the mixed pair sample also appears similarly underluminous. A spatial analysis shows that the X-ray emission from pairs of both types typically has an extent of 10 - 50 kpc, much smaller than the group intergalactic medium, and thus likely originates from the galaxies. CPG 564, the most X-ray luminous early-type pair, 4.7x10^42^ergs/s, is an exception. The extent of its X-ray emission, greater than 169 kpc, and HWHM, {~}80 kpc, is comparable to that expected from an intergalactic medium. The sample shows only a weak correlation, {~}81% confidence, between L_X_ and L_b_, presumably due to variations in gas content within the galaxies. No correlation between L_X_ and the pair velocity difference ({delta}v), separation ({delta}r), or far-infrared luminosity (L_fir_) is found, although the detection rate is low, 22%.
- ID:
- ivo://CDS.VizieR/J/A+AS/129/577
- Title:
- AO 0235+164 BVRI photometry
- Short Name:
- J/A+AS/129/577
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present the results of the optical and radio monitoring of the BL Lac object AO 0235+164 during a faint state. In both optical and radio bands the source has been observed at the faintest ever recorded levels, reaching V=19.80 and F_22GHz_=0.34Jy. In the optical bands we still see variability with amplitudes up to 1.5 magnitudes on timescales from days to weeks. The radio variability is less dramatic, but in general follows the optical behaviour. A correlation between general trends in the optical and radio behaviour of AO 0235+164 may be recognized in the data from the present monitoring as well as in the historical light curves, suggesting a `base' mechanism responsible for the emission at both frequencies. A good candidate is a synchrotron process in the relativistic jet. Optical flares with no corresponding radio counterparts have been observed too. These events may be interpreted in terms of microlensing by a foreground galaxy.
- ID:
- ivo://CDS.VizieR/J/ApJ/806/248
- Title:
- AO imaging of KOIs with gas giant planets
- Short Name:
- J/ApJ/806/248
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- As hundreds of gas giant planets have been discovered, we study how these planets form and evolve in different stellar environments, specifically in multiple stellar systems. In such systems, stellar companions may have a profound influence on gas giant planet formation and evolution via several dynamical effects such as truncation and perturbation. We select 84 Kepler Objects of Interest (KOIs) with gas giant planet candidates. We obtain high-angular resolution images using telescopes with adaptive optics (AO) systems. Together with the AO data, we use archival radial velocity data and dynamical analysis to constrain the presence of stellar companions. We detect 59 stellar companions around 40 KOIs for which we develop methods of testing their physical association. These methods are based on color information and galactic stellar population statistics. We find evidence of suppressive planet formation within 20 AU by comparing stellar multiplicity. The stellar multiplicity rate (MR) for planet host stars is 0_-0_^+5^% within 20 AU. In comparison, the stellar MR is 18%+/-2% for the control sample, i.e., field stars in the solar neighborhood. The stellar MR for planet host stars is 34%+/-8% for separations between 20 and 200 AU, which is higher than the control sample at 12%+/-2%. Beyond 200 AU, stellar MRs are comparable between planet host stars and the control sample. We discuss the implications of the results on gas giant planet formation and evolution.
- ID:
- ivo://CDS.VizieR/J/ApJ/672/40
- Title:
- AO 0235+164 outburst in 2006 December
- Short Name:
- J/ApJ/672/40
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present the results of polarimetric (R-band) and multicolor photometric (BVRIJHK) observations of the blazar AO 0235+16 during an outburst in 2006 December. The data reveal a short timescale of variability (several hours), which increases from optical to near-IR wavelengths; even shorter variations are detected in polarization. The flux density correlates with the degree of polarization, and at the maximum degree of polarization the electric vector tends to align with the parsec-scale jet direction. We find that a variable component with a steady power-law spectral energy distribution and very high optical polarization (30%-50%) is responsible for the variability. We interpret these properties of the blazar within a model of a transverse shock propagating down the jet. In this case a small change in the viewing angle of the jet, by ~<1{deg}, and a decrease in the shocked plasma compression by a factor of ~1.5 are sufficient to account for the variability.
1028. AO Ser VR light curves
- ID:
- ivo://CDS.VizieR/J/AJ/139/1360
- Title:
- AO Ser VR light curves
- Short Name:
- J/AJ/139/1360
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present the first multiband photometry for the semidetached eclipsing binary AO Serpentis, observed on seven nights between 2009 April and July at the Weihai Observatory of Shandong University. By using the 2003 version of the Wilson-Devinney code, the photometric solutions of AO Ser and a similar object V338 Her were (re)deduced. The spectral types and orbital periods are A2 and P=0.8793-days for AO Ser, F1V and P=1.3057-days for V338 Her.
- ID:
- ivo://CDS.VizieR/J/A+AS/109/425
- Title:
- AO Vel four-colour photometry
- Short Name:
- J/A+AS/109/425
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- (no description available)
- ID:
- ivo://org.gavo.dc/apo/res/apo/frames
- Title:
- Apache Point observations of lensed quasars
- Short Name:
- apo.frames
- Date:
- 27 Dec 2024 08:31:01
- Publisher:
- The GAVO DC team
- Description:
- Observations of the lensed quasar Q2237+0305 performed between 1995 and 1998.
