- ID:
- ivo://CDS.VizieR/J/A+A/592/A48
- Title:
- Annotations to the second Planck cluster catalog
- Short Name:
- J/A+A/592/A48
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present an all sky map of the y-type distortion calculated from the full mission Planck HFI (High Frequency Instrument) data using the recently proposed approach to component separation based on parametric model fitting and model selection. This simple model selection approach allows us to distinguish between carbon monoxide (CO) line emission and y-type distortion, something that is not possible using the internal linear combination based methods. We create a mask to cover the regions of significant CO emission relying on the information in the {chi}^2^ map obtained when fitting for the y-distortion and CO emission to the lowest four HFI channels. We revisit the second Planck cluster catalog and try to quantify the quality of the cluster candidates in an approach that is similar in spirit to Aghanim et al. (2015A&A...580A.138A). We find that at least 93% of the clusters in the cosmology sample are free of CO contamination. We also find that 59% of unconfirmed candidates may have significant contamination from molecular clouds. We agree with Planck Collaboration et al. (2016, A&A, in press., arXiv:1502.01598) for the worst offenders. We suggest an alternative validation strategy of measuring and subtracting the CO emission from the Planck cluster candidates using radio telescopes thus improving the reliability of the catalog. Our CO mask and annotations to the Planck cluster catalog identifying cluster candidates with possible CO contamination are made publicly available.
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- ID:
- ivo://CDS.VizieR/J/A+A/626/A69
- Title:
- An old nova remnant in M22
- Short Name:
- J/A+A/626/A69
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- A nova is a cataclysmic event on the surface of a white dwarf in a binary system that increases the overall brightness by several orders of magnitude. Although binary systems with a white dwarf are expected to be overabundant in globular clusters (GCs) compared to the Galaxy, only two novae from Galactic globular clusters have been observed. We present the discovery of an emission nebula in the Galactic globular cluster M 22 (NGC 6656) in observations made with the integral-field spectrograph MUSE. We extract the spectrum of the nebula and use the radial velocity determined from the emission lines to confirm that the nebula is part of NGC 6656. Emission-line ratios are used to determine the electron temperature and density. It is estimated to have a mass of 1 to 17x10^-5^ solar masses. This mass and the emission-line ratios indicate that the nebula is a nova remnant. Its position coincides with the reported location of a 'guest star', an ancient Chinese term for transients, observed in May 48 BCE. With this discovery, this nova may be one of the oldest confirmed extrasolar events recorded in human history.
- ID:
- ivo://CDS.VizieR/J/A+A/615/A42
- Title:
- Anomalous extinction sightlines stars polarisation
- Short Name:
- J/A+A/615/A42
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Highly reddened type Ia supernovae (SNe Ia) with low total-to-selective visual extinction ratio values, RV, also show peculiar linear polarization wavelength dependencies with peak polarizations at short wavelengths ({lambda}_max_<~0.4um). It is not clear why sightlines to SNe Ia display such different continuum polarization profiles from interstellar sightlines in the Milky Way with similar RV values. We investigate polarization profiles of a sample of Galactic stars with low RV values, along anomalous extinction sightlines, with the aim to find similarities to the polarization profiles that we observe in SN Ia sightlines. We undertook spectropolarimetry of 14 stars, used archival data for 3 additional stars, and ran dust extinction and polarization simulations (by adopting the picket-fence alignment model) to infer a simple dust model (size distribution, alignment) that can reproduce the observed extinction and polarization curves. Our sample of Galactic stars with low RV values and anomalous extinction sightlines displays normal polarization profiles with an average {lambda}_max_~0.53um, and is consistent within 3{sigma} to a larger coherent sample of Galactic stars from the literature. Despite the low RV values of dust toward the stars in our sample, the polarization curves do not show any similarity to the continuum polarization curves observed toward SNe Ia with low RV values. There is a correlation between the best-fit Serkowski parameters K and {lambda}_max_, but we did not find any significant correlation between RV and {lambda}_max_. Our simulations show that the K-{lambda}_max_ relationship is an intrinsic property of polarization. Furthermore, we have shown that in order to reproduce polarization curves with normal {lambda}_max_ and low RV values, a population of large (a >=0.1um) interstellar silicate grains must be contained in the dust composition.
- ID:
- ivo://CDS.VizieR/J/MNRAS/463/1332
- Title:
- Anomalous RRd stars in Magellanic Clouds
- Short Name:
- J/MNRAS/463/1332
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We report the discovery of a new subclass of double-mode RR Lyrae stars in the Large and Small Magellanic Clouds. The sample of 22 pulsating stars has been extracted from the latest edition of the Optical Gravitational Lensing Experiment collection of RR Lyrae variables in the Magellanic System. The stars pulsating simultaneously in the fundamental (F) and first-overtone (1O) modes have distinctly different properties than regular double-mode RR Lyrae variables (RRd stars). The P_1O_/P_F_ period ratios of our anomalous RRd stars are within a range of 0.725-0.738, while 'classical' double-mode RR Lyrae variables have period ratios in the range of 0.742-0.748. In contrast to the typical RRd stars, in the majority of the anomalous pulsators, the F-mode amplitudes are higher than the 1O-mode amplitudes. The light curves associated with the F-mode in the anomalous RRd stars show different morphology than the light curves of, both, regular RRd stars and single-mode RRab stars. Most of the anomalous double-mode stars show long-term modulations of the amplitudes (Blazhko-like effect). Translating the period ratios into the abundance parameter, Z, we find for our stars Z{in}(0.002, 0.005) - an order of magnitude higher values than typical for RR Lyrae stars. The mass range of the RRd stars inferred from the W_I_ versus P_F_ diagram is (0.55-0.75)M_{sun}_. These parameters cannot be accounted for with single star evolution assuming a Reimers-like mass-loss. Much greater mass-loss caused by interaction with other stars is postulated. We blame the peculiar pulsation properties of our stars to the parametric resonance instability of the 1O-mode to excitation of the F- and 2O-modes as with the inferred parameters of the stars 2{omega}_1O_~={omega}_F_+{omega}_2O_.
- ID:
- ivo://CDS.VizieR/VIII/3
- Title:
- An Optical Catalogue of Radio Galaxies
- Short Name:
- VIII/3
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- This catalog contains basic optical information on all known radio galaxies (with L[radio] greater than about 10**[41] ergs/s) that had been identified as of 1979 and for which measured redshifts were available. The data include the right ascension and declination (1950); galaxy (optical) type; visual magnitude; photoelectric colors; redshift (z) and the spectral lines on which the redshift measurements were based; coordinate designations; radio flux and frequency; radio spectral index; other names; and the references for the galaxy identification, photometric data, redshift, radio flux, radio spectral index, and radio map number. Note that the ADC version of this catalog differs somewhat from the original printed catalog in that some fields were added or modified and other fields reordered. In addition to the catalog data file itself, two additional files containing the list of references for the catalog are also available. The first reference list is in alphabetical order, and the second is in numerical order.
- ID:
- ivo://CDS.VizieR/J/AJ/161/196
- Title:
- An optical overview of blazars with LAMOST. I.
- Short Name:
- J/AJ/161/196
- Date:
- 16 Mar 2022 11:51:00
- Publisher:
- CDS
- Description:
- The extragalactic {gamma}-rays sky observed by the Fermi Large Area Telescope (LAT) is dominated by blazars. In the fourth release of the Fermi LAT Point Source Catalog (4FGL) are sources showing a multifrequency behavior similar to that of blazars but lacking an optical spectroscopic confirmation of their nature, known as blazar candidates of uncertain type (BCUs). We aim at confirming the blazar nature of BCUs and test if new optical spectroscopic observations can reveal spectral features, allowing us to get a redshift estimate for known BL Lac objects. We also aim to search for and discover changing-look blazars (i.e., blazars that show a different classification at different epochs). We carry out an extensive search for optical spectra available in the Large Sky Area Multi-object Fibre Spectroscopic Telescope (LAMOST) Data Release 5 (DR5) archive. We select sources out of the 4FGL catalog, the list of targets from our follow-up spectroscopic campaign of unidentified or unassociated {gamma}-ray sources, and the multifrequency catalog of blazars: the Roma-BZCAT. We select a total of 392 spectra. We also compare some of the LAMOST spectra with those available in the literature. We classify 20 BCUs confirming their blazar-like nature. Then we obtain 15 new redshift estimates for known blazars. We discover 26 transitional (i.e., changing-look) blazars that changed their classification. Finally, we are able to confirm the blazar-like nature of six BL Lac candidates. All remaining sources analyzed agree with previous classifications. BL Lac objects are certainly the most elusive type of blazars in the {gamma}-ray extragalactic sky.
- ID:
- ivo://CDS.VizieR/II/97
- Title:
- ANS UV Catalogue of Point Sources
- Short Name:
- II/97
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- This catalog is a result of the observations made with the Astronomical Netherlands Satellite (ANS) which operated between October 1974 and April 1976. The ANS satellite observed in five UV channels centered around 150, 180, 220, 250 and 330nm. The photometric bands are: -------------------------------------------------------------------------- Band designation 15N 15W 18 22 25 33 -------------------------------------------------------------------------- Central wavelength (nm) 154.5 154.9 179.9 220.0 249.3 329.4 Bandwidth (nm) 5.0 14.9 14.9 20.0 15.0 10.1 -------------------------------------------------------------------------- The reported magnitudes were obtained from mean count rates converted to fluxes using the ANS absolute calibration of Wesselius et al. (1980A&A....85..221W). In addition to the ultraviolet magnitudes, the catalog contains positions taken from the satellite pointing, spectral types, and UBV data from other sources as well as comments on duplicity, variability, and miscellaneous notes concerning individual objects.
- ID:
- ivo://CDS.VizieR/J/AJ/140/75
- Title:
- Antennae galaxies (NGC 4038/4039) revisited
- Short Name:
- J/AJ/140/75
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The Advanced Camera for Surveys and the Near Infrared Camera and Multi-Object Spectrometer (NICMOS) have been used to obtain new Hubble Space Telescope images of NGC 4038/4039 ("The Antennae"). These new observations allow us to better differentiate compact star clusters from individual stars, based on both size and color.
- ID:
- ivo://CDS.VizieR/J/other/PhRvD/103.H3016
- Title:
- Antimatter sources E flux sensitivity
- Short Name:
- J/other/PhRvD/10
- Date:
- 22 Feb 2022
- Publisher:
- CDS
- Description:
- It is generally taken for granted that our Universe is free of antimatter objects and domains. This certitude has recently been challenged by the possible detection of anti-helium nuclei by AMS-02. Should the observation be confirmed, the existence of nearby antistars would make a plausible hypothesis to explain the origin of the antinuclei. In this paper we use the 10-years F Large Area Telescope (LAT) gamma-ray source catalog to set constraints on the abundance of antistars around the Sun. We identify in the catalog 14 antistar candidates not associated with any objects belonging to established gamma-ray source classes and with a spectrum compatible with baryon-antibaryon annihilation. We use them along with an estimate of the LAT sensitivity to antistars to set upper limits on the local antistar fraction f_bar*_ with respect to normal stars. We provide parametric limits as a function of the closest antistar mass, velocity, and surrounding matter density. We also employ a novel Monte~Carlo method to set limits for a few hypotheses about the antistar population. For a population with properties equivalent to those of regular stars concentrated in the Galactic disk we obtain f_bar*_<2.5x10^-6^ at 95% confidence level, which is 20 times more constraining than limits previously available. For a primordial population of antistars distributed in the Galactic halo we obtain new local upper limits which decrease as a function of antistar mass M from f_bar*_<0.2 at 95% confidence level for M=1M_{sun}_ to f_bar*_<1.6x10^-4^ at 95% confidence level for M=10M_{sun}_. By combining these limits with existing microlensing constraints for lighter objects in the Magellanic clouds, we infer that a primordial population of halo antistars must have a density lower than O (10^-5^pc^-3^) to O (10^-2^pc^-3^) depending on their masses. Our limits can constrain models for the origin and propagation of antinuclei in cosmic rays.
- ID:
- ivo://CDS.VizieR/J/MNRAS/477/1760
- Title:
- Antlia galaxies geometric parameters
- Short Name:
- J/MNRAS/477/1760
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present a statistical isophotal analysis of 138 early-type galaxies in the Antlia cluster, located at a distance of ~35Mpc. The observational material consists of CCD images of four 36x36arcmin^2^ fields obtained with the MOSAIC II camera at the Blanco 4-m telescope at Cerro Tololo Interamerican Observatory. Our present work supersedes previous Antlia studies in the sense that the covered area is four times larger, the limiting magnitude is M_B_~-9.6mag, and the surface photometry parameters of each galaxy are derived from Sersic model fits extrapolated to infinity. In a companion previous study we focused on the scaling relations obtained by means of surface photometry, and now we present the data, on which the previous paper is based, the parameters of the isophotal fits as well as an isophotal analysis. For each galaxy, we derive isophotal shape parameters along the semimajor axis and search for correlations within different radial bins. Through extensive statistical tests, we also analyse the behaviour of these values against photometric and global parameters of the galaxies themselves. While some galaxies do display radial gradients in their ellipticity ({epsilon}) and/or their Fourier coefficients, differences in mean values between adjacent regions are not statistically significant. Regarding Fourier coefficients, dwarf galaxies usually display gradients between all adjacent regions, while non-dwarfs tend to show this behaviour just between the two outermost regions. Globally, there is no obvious correlation between Fourier coefficients and luminosity for the whole magnitude range (-12>=M_V_>=-22); however, dwarfs display much higher dispersions at all radii.
