- ID:
- ivo://CDS.VizieR/J/A+A/477/125
- Title:
- Microquasar candidates
- Short Name:
- J/A+A/477/125
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Microquasars are ideal natural laboratories for understanding accretion/ejection processes, studying the physics of relativistic jets, and testing gravitational phenomena. Nevertheless, these objects are difficult to find in our Galaxy. The main goal of this work is to increase the number of known systems of this kind, which should allow better testing of high-energy phenomena and more realistic statistical studies of this galactic population to be made. We have developed an improved search strategy based on positional cross-identification with very restrictive selection criteria to find new MQs, taking advantage of more sensitive modern X-ray data. To do this, we made combined use of the radio, infrared, and X-ray properties of the sources, using different available catalogs.
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Search Results
- ID:
- ivo://CDS.VizieR/J/A+A/617/A83
- Title:
- MIDI atlas of low- and intermediate-mass YSOs
- Short Name:
- J/A+A/617/A83
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Protoplanetary disks show large diversity regarding their morphology and dust composition. With mid-infrared interferometry the thermal emission of disks can be spatially resolved, and the distribution and properties of the dust within can be studied. Our aim is to perform a statistical analysis on a large sample of 82 disks around low- and intermediate-mass young stars, based on mid-infrared interferometric observations. We intend to study the distribution of disk sizes, variability, and the silicate dust mineralogy. Archival mid-infrared interferometric data from the MIDI instrument on the Very Large Telescope Interferometer are homogeneously reduced and calibrated. Geometric disk models are used to fit the observations to get spatial information about the disks. An automatic spectral decomposition pipeline is applied to analyze the shape of the silicate feature. We present the resulting data products in the form of an atlas, containing N band correlated and total spectra, visibilities, and differential phases. The majority of our data can be well fitted with a continuous disk model, except for a few objects, where a gapped model gives a better match. From the mid-infrared size-luminosity relation we find that disks around T Tauri stars are generally colder and more extended with respect to the stellar luminosity than disks around Herbig Ae stars. We find that in the innermost part of the disks (r<~1au) the silicate feature is generally weaker than in the outer parts, suggesting that in the inner parts the dust is substantially more processed. We analyze stellar multiplicity and find that in two systems (AB Aur and HD 72106) data suggest a new companion or asymmetric inner disk structure. We make predictions for the observability of our objects with the upcoming Multi-AperTure mid- Infrared SpectroScopic Experiment (MATISSE) instrument, supporting the practical preparations of future MATISSE observations of T Tauri stars.
- ID:
- ivo://CDS.VizieR/J/A+A/418/465
- Title:
- Mid-infrared and hard X-ray emission in AGN
- Short Name:
- J/A+A/418/465
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We use mid-infrared spectral decomposition to separate the 6{mu}m mid-infrared AGN continuum from the host emission in the ISO low resolution spectra of 71 active galaxies and compare the results to observed and intrinsic 2-10keV hard X-ray fluxes from the literature.
- ID:
- ivo://CDS.VizieR/J/A+A/545/A56
- Title:
- Mid-infrared diameter of 4 AGBs
- Short Name:
- J/A+A/545/A56
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Asymptotic giant branch (AGB) stars are one of the largest distributors of dust into the interstellar medium. However, the wind formation mechanism and dust condensation sequence leading to the observed high mass-loss rates have not yet been constrained well observationally, in particular for oxygen-rich AGB stars. The immediate objective in this work is to identify molecules and dust species which are present in the layers above the photosphere, and which have emission and absorption features in the mid-infrared (IR), causing the diameter to vary across the N- band, and are potentially relevant for the wind formation. Mid-IR (8-13 micron) interferometric data of four oxygen-rich AGB stars (R Aql, R Aqr, R Hya, and W Hya) and one carbon-rich AGB star (V Hya) were obtained with MIDI/VLTI between April 2007 and September 2009. The spectrally dispersed visibility data are analyzed by fitting a circular fully limb-darkened disk (FDD). The FDD diameter as function of wavelength is similar for all oxygen-rich stars. The apparent size is almost constant between 8 and 10 micron and gradually increases at wavelengths longer than 10 micron. The apparent FDD diameter in the carbon-rich star V Hya essentially decreases from 8 to 12 micron. The FDD diameters are about 2.2 times larger than the photospheric diameters estimated from K-band observations found in the literature. The silicate dust shells of R Aql, R Hya and W Hya are located fairly far away from the star, while the silicate dust shell of R Aqr and the amorphous carbon (AMC) and SiC dust shell of V Hya are found to be closer to the star at around 8 photospheric radii. Phase-to-phase variations of the diameters of the oxygen-rich stars could be measured and are on the order of 15% but with large uncertainties. From a comparison of the diameter trend with the trends in RR Sco and S Ori it can be concluded that in oxygen-rich stars the overall larger diameter originates from a warm molecular layer of H2O, and the gradual increase longward of 10 micron can be most likely attributed to the contribution of a close Al2O3 dust shell. The chromatic trend of the Gaussian FWHM in V Hya can be explained with the presence of AMC and SiC dust. The observations suggest that the formation of amorphous Al2O3 in oxygen-rich stars occurs mainly around or after visual minimum. However, no firm conclusions can be drawn concerning the mass-loss mechanism. Future modeling with hydrostatic and self-consistent dynamical stellar atmospheric models will be required for a more certain understanding.
- ID:
- ivo://CDS.VizieR/J/A+A/530/A120
- Title:
- Mid-infrared diameter of W Hya
- Short Name:
- J/A+A/530/A120
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Mid-infrared (N-band) interferometric data of W Hya were obtained with MIDI/VLTI between April 2007 and September 2009, covering nearly three pulsation cycles. The spectrally dispersed visibility data of all 75 observations were analyzed by fitting a circular fully limb-darkened disk (FDD) model to all data and individual pulsation phases. Asymmetries were studied with an elliptical FDD. Modeling results in an apparent angular FDD diameter of W Hya of about (80+/-1.2)mas (7.8AU) between 8 and 10 micron, which corresponds to an about 1.9 times larger diameter than the photospheric one. The diameter gradually increases up to (105+/-1.2)mas (10.3AU) at 12 micron. In contrast, the FDD relative flux fraction decreases from (0.85+/-0.02) to (0.77+/-0.02), reflecting the increased flux contribution from a fully resolved surrounding silicate dust shell. The asymmetric character of the extended structure could be confirmed. An elliptical FDD yields a position angle of (11+/-20)deg and an axis ratio of (0.87+/-0.07). A weak pulsation dependency is revealed with a diameter increase of (5.4+/-1.8)mas between visual minimum and maximum, while detected cycle-to-cycle variations are smaller.
- ID:
- ivo://CDS.VizieR/J/A+A/445/971
- Title:
- Mid-infrared images of W75N
- Short Name:
- J/A+A/445/971
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- An infrared study that includes ground-based mid-infrared images between 8.7 and 18.7um and IRAC images at 3.6, 4.5, 5.8 and 8.0um of the W75 N massive star forming region is presented. The 12.5um image shows the presence of four mid-infrared sources in the region W75 N(B), three of which have bright near-infrared counterparts, IRS 1, IRS 2 and IRS 3, all with significant excess emission at lambda>2.0um. IRS 2 has a steep energy distribution and the computed infrared luminosity is consistent with the presence of a young B3 star. The observed IRAC colors of IRS 3 indicate that this source is a Class II intermediate mass young star, consistent with its infrared energy distribution and luminosity. The fourth, newly discovered, mid-infrared source appears coincident with the ultracompact HII region VLA 3, and is located within the millimeter core MM 1. We derived a luminosity of ~750L_{sun}_ and a visual extinction A_V_~90 for this source. From the IRAC images, we detected 75 sources in an area of 120"x120" centered in W75 N. At least 25 of these sources are associated with the molecular cloud and form a young stellar cluster as shown in the IRAC two-color and the H-Ks versus Ks-[3.6] diagrams.
- ID:
- ivo://CDS.VizieR/J/AJ/127/3075
- Title:
- Mid-infrared population of ELAIS-S1 sample
- Short Name:
- J/AJ/127/3075
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present a multiwavelength catalog (15{mu}m, R-band, K-band, and 1.4GHz flux) plus spectroscopic identifications for 406 15{mu}m sources detected in the European Large Area ISO Survey (ELAIS) region S1, over the flux density range 0.5<S15{mu}m<150mJy. Three hundred thirty-two (~82%) sources are optically identified down to R~23.0. Spectra or bona fide stellar identifications are obtained for 290 objects (~88% of the optically identified sources). The areal coverage, mid-infrared (MIR) and optical completeness of the sample are discussed in order to allow statistical and evolutionary analyses.
- ID:
- ivo://CDS.VizieR/J/A+A/451/57
- Title:
- Mid-infrared properties of luminous IR galaxies
- Short Name:
- J/A+A/451/57
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present evidence that the mid infrared (MIR, rest frame 5-30{mu}m) is a good tracer of the total infrared luminosity, L(IR)(=L[8-1000{mu}m]), and star formation rate (SFR), of galaxies up to z~1.3. We use deep MIR images from the Infrared Space Observatory (ISO) and the Spitzer Space Telescope in the Northern field of the Great Observatories Origins Deep Survey (GOODS-N) together with VLA radio data to compute three independant estimates of L(IR). The L(IR,MIR) derived from the observed 15 and/or 24{mu}m flux densities using a library of template SEDs, and L(IR,radio), derived from the radio (1.4 and/or 8.5GHz) using the radio-far infrared correlation, agree with a 1-sigma dispersion of 40%. We use the k-correction as a tool to probe different parts of the MIR spectral energy distribution (SED) of galaxies as a function of their redshift and find that on average distant galaxies present MIR SEDs very similar to local ones.
- ID:
- ivo://CDS.VizieR/J/A+A/414/825
- Title:
- Mid-infrared spectroscopy of LINERs
- Short Name:
- J/A+A/414/825
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present a comprehensive comparative high resolution mid-IR spectroscopic and X-ray imaging investigation of LINERs using archival observations from the ISO-SWS and the Chandra Advanced CCD Imaging Spectrometer. Although the sample is heterogeneous and incomplete, this is the first comprehensive study of the mid-infrared fine structure line emission of LINERs.
- ID:
- ivo://CDS.VizieR/J/MNRAS/454/766
- Title:
- Mid-infrared-X-ray correlation for local AGNs
- Short Name:
- J/MNRAS/454/766
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present an updated mid-infrared (MIR) versus X-ray correlation for the local active galactic nuclei (AGN) population based on the high angular resolution 12 and 18{mu}m continuum fluxes from the AGN subarcsecond MIR atlas and 2-10 keV and 14-195 keV data collected from the literature. We isolate a sample of 152 objects with reliable AGN nature and multi-epoch X-ray data and minimal MIR contribution from star formation. Although the sample is not homogeneous or complete, we show that our results are unlikely to be affected by significant biases. The MIR-X-ray correlation is nearly linear and within a factor of 2 independent of the AGN type and the wavebands used. The observed scatter is <0.4 dex. A possible flattening of the correlation slope at the highest luminosities probed (~10^45^ erg/s) towards low MIR luminosities for a given X-ray luminosity is indicated but not significant. Unobscured objects have, on average, an MIR-X-ray ratio that is only <=0.15 dex higher than that of obscured objects. Objects with intermediate X-ray column densities (22<logN_H_<23) actually show the highest MIR-X-ray ratio on average. Radio-loud objects show a higher mean MIR-X-ray ratio at low luminosities while the ratio is lower than average at high luminosities. This may be explained by synchrotron emission from the jet contributing to the MIR at low luminosities and additional X-ray emission at high luminosities. True Seyfert 2 candidates do not show any deviation from the general behaviour suggesting that they possess a dusty obscurer as in other AGN. Double AGN also do not deviate. Finally, we show that the MIR-X-ray correlation can be used to investigate the AGN nature of uncertain objects. Specifically, we give equations that allow us to determine the intrinsic 2-10 keV luminosities and column densities for objects with complex X-ray properties to within 0.34 dex. These techniques are applied to the uncertain objects of the remaining AGN MIR atlas, demonstrating the usefulness of the MIR-X-ray correlation as an empirical tool.
