- ID:
- ivo://CDS.VizieR/J/ApJ/610/247
- Title:
- M31 supersoft and quasi-soft X-ray sources
- Short Name:
- J/ApJ/610/247
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We report on very soft X-ray sources (VSSs) in M31. In a survey that was most sensitive to soft sources in four 8'x8' regions covered by Chandra's ACIS-S S3 CCD, we find 33 VSSs that appear to belong to M31. Fifteen VSSs have spectral characteristics mirroring the supersoft X-ray sources studied in the Magellanic Clouds and Milky Way (kT_eff_<=100eV); we therefore call these "classical" supersoft sources, or simply supersoft sources (SSSs). Eighteen VSSs may have either small (<10%) hard components or slightly higher effective temperatures (but still less than 350eV). We refer to these VSSs as quasi-soft sources (QSSs).
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- ID:
- ivo://CDS.VizieR/J/MNRAS/474/3324
- Title:
- Multicomponent matched filter test
- Short Name:
- J/MNRAS/474/3324
- Date:
- 02 Mar 2022 00:06:44
- Publisher:
- CDS
- Description:
- We describe a multicomponent matched filter (MCMF) cluster confirmation tool designed for the study of large X-ray source catalogues produced by the upcoming X-ray all-sky survey mission eROSITA. We apply the method to confirm a sample of 88 clusters with redshifts 0.05<z<0.8 in the recently published 2RXS catalogue from the ROSAT All-Sky Survey (RASS) over the 208 deg^2^ region overlapped by the Dark Energy Survey (DES) Science Verification (DES-SV) data set. In our pilot study, we examine all X-ray sources, regardless of their extent. Our method employs a multicolour red sequence (RS) algorithm that incorporates the X-ray count rate and peak position in determining the region of interest for follow-up and extracts the positionally and colour-weighted optical richness {lambda}_MCMF_ as a function of redshift for each source. Peaks in the {lambda}_MCMF_-redshift distribution are identified and used to extract photometric redshifts, richness and uncertainties. The significances of all optical counterparts are characterized using the distribution of richnesses defined along random lines of sight. These significances are used to extract cluster catalogues and to estimate the contamination by random superpositions of unassociated optical systems. The delivered photometric redshift accuracy is {delta}z/(1+z)=0.010. We find a well-defined X-ray luminosity-{lambda}_MCMF_ relation with an intrinsic scatter of {delta}ln({lambda}_MCMF_|Lx)=0.21. Matching our catalogue with the DES-SV redMaPPer catalogue yields good agreement in redshift and richness estimates; comparing our catalogue with the South Pole Telescope (SPT) selected clusters shows no inconsistencies. SPT clusters in our data set are consistent with the high-mass extension of the RASS-based {lambda}_MCMF_-mass relation.
- ID:
- ivo://CDS.VizieR/J/other/RMxAA/35.187
- Title:
- Multifrequency catalog of LINERs
- Short Name:
- J/other/RMxAA/35
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present the first Catalog of Low Ionization Emission Line Galaxies (LINERs or Liners, which is the simplest name, and which we shall adopt in what follows). The Catalog "MCL" (Multifrequency Catalog of Liners), contains 476 entries and contains both broad-band and monochromatic emission data (ranging from radio to X-ray frequencies) of colors, and other data compiled from the literature and various data bases, as indicated in the references. Most of the galaxies can be considered "pure" Liners on the basis of the Veilleux & Osterbrock (1987ApJS...63..295V) classification as suggested by Ho, Filippenko, & Sargent (1997ApJS..112..315H). However, a considerable number of transition (Liners-H II or Liners-Starburst) objects are also included. One of the open questions, is whether Liners should be considered as a class of galaxies (like Seyfert galaxies for instance) or rather, as an heterogeneous group of objects. We believe the study of Liners as a group is very interesting, precisely because they very likely represent a transition between non-thermal and starburst activity, and probably also between "active" and "non- active" galaxies. This catalog may be used as a basis for statistical research. A preliminary discussion of the main statistical properties of Liners, in the range from radio to X-ray frequencies, is given here.
- ID:
- ivo://CDS.VizieR/J/A+AS/106/303
- Title:
- Multifrequency observations of ROSAT sources
- Short Name:
- J/A+AS/106/303
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We report on results of multifrequency radio continuum observations with the Effelsberg 100-m telescope of 234 radio sources which have counterparts in the ROSAT all-sky survey. Observations have been made at 21 cm, 11 cm, 6 cm and 2.8 cm wavelength in the flux density range above 20 mJy. We have determined the spectrum, size, linear polarization and improved positions of these sources. We give the statistical properties of the ROSAT selected radio sources and compare them with results from unbiased radio source surveys so far available.
- ID:
- ivo://CDS.VizieR/J/A+A/573/A76
- Title:
- Multifrequency study of NL Seyfert 1 galaxies
- Short Name:
- J/A+A/573/A76
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- High-energy {gamma}-rays, which are produced by powerful relativistic jets, are usually associated with blazars and radio galaxies. In the current active galactic nuclei (AGN) paradigm, such jets are almost exclusively launched from massive elliptical galaxies. Recently, however, Fermi/LAT detected {gamma}-rays from a few narrow-line Seyfert 1 galaxies and thus confirmed the presence of relativistic jets in them. Since NLS1 galaxies are assumed to be young evolving AGN, they offer a unique opportunity to study the production of relativistic jets in late-type galaxies. Our aim is to estimate by which processes the emission of various kinds is produced in NLS1 galaxies and to study how emission properties are connected to other intrinsic AGN properties. We have compiled the so far largest multiwavelength database of NLS1 sources. This allowed us to explore correlations between different wavebands and source properties using, for example, Pearson and Spearman correlations and principal component analysis. We did this separately for radio-loud and radio-quiet sources.
- ID:
- ivo://CDS.VizieR/J/other/Ser/166.13
- Title:
- Multi-frequency study of the Pavo field
- Short Name:
- J/other/Ser/166.
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We test the prediction of Hamilton and Helfand (<A HREF="http://simbad.cds.unistra.fr/simbad/sim-ref?bibcode=1993ApJ...418...55H%201993ApJ...418...55H">1993ApJ...418...55H 1993ApJ...418...55H</A>) that faint radio selected galaxies are a new class contributing to the diffuse X-ray background (XRB) radiation. The test is based on the correlation of X-ray, optical and radio positions for sources detected in ROSAT (S<SUB>0.08–2.4keV</SUB>>6x10<SUP>–15</SUP>erg/s/cm<SUP>2</SUP>, 69 sources) and ATCA (S<SUB>1.42GHz</SUB>>250uJy, 93 sources) observations of the Einstein Pavo field. A total of six ATCA radio sources inside the inner ring of the ROSAT image are located within 10" of the ROSAT X-ray positions, with one associated by random chance.
- ID:
- ivo://CDS.VizieR/J/MNRAS/414/3084
- Title:
- Multi-waveband analysis of 12um galaxies
- Short Name:
- J/MNRAS/414/3084
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present a multi-waveband analysis of a 126-galaxy sub-sample of the 12um galaxy sample (12MGS), for which we have carried out a detailed X-ray spectral analysis in a previous paper. We determine the activity class of the galaxies by way of optical-line ratio diagnostics and characterize the optical classes by their X-ray, 12um and [OIII] luminosities and X-ray spectral properties.
- ID:
- ivo://CDS.VizieR/J/PASJ/60/161
- Title:
- Multi-wave band emission from blazars
- Short Name:
- J/PASJ/60/161
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We studied the correlations of the flux of the broad-line emission (FBLR) with the X-ray emission flux, optical emission flux at 5500{AA} and radio emission flux at 5GHz, respectively, for a large sample of 50 blazars (39 flat-spectrum radio quasars (FSRQs) and 11 BL Lac objects).
- ID:
- ivo://CDS.VizieR/J/ApJ/851/33
- Title:
- Multi-wavelength analysis of CGRaBS blazars
- Short Name:
- J/ApJ/851/33
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present the results of a multi-frequency, time-averaged analysis of blazars included in the Candidate Gamma-ray Blazar Survey catalog. Our sample consists of 324 {gamma}-ray detected ({gamma}-ray loud) and 191 {gamma}-ray undetected ({gamma}-ray quiet) blazars; we consider all the data up to 2016 April 1. We find that both the {gamma}-ray loud and {gamma}-ray quiet blazar populations occupy similar regions in the WISE color-color diagram, and {gamma}-ray loud sources are brighter in the radio and X-ray bands. A simple one-zone synchrotron inverse-Compton emission model is applied to derive the physical properties of both populations. We find that the central black hole mass and accretion disk luminosity (L_disk_) computed from the modeling of the optical-UV emission with a Shakura-Sunyaev disk reasonably matches that estimated from the optical spectroscopic emission-line information. A significantly larger Doppler boosting in the {gamma}-ray loud blazars is noted, and their jets are more radiatively efficient. On the other hand, the {gamma}-ray quiet objects are more MeV-peaked and thus could be potential targets for next-generation MeV missions. Our results confirm earlier findings about the accretion-jet connection in blazars; however, many of the {gamma}-ray quiet blazars tend to deviate from the recent claim that the jet power exceeds L_disk_ in blazars. A broadband study, considering a larger set of {gamma}-ray quiet objects and also including BL Lacs, will be needed to confirm/reject this hypothesis as well as to verify the evolution of the powerful high-redshift blazars into their low-power nearby counterparts.
- ID:
- ivo://CDS.VizieR/J/A+A/641/A62
- Title:
- Multi-wavelength census of blazars
- Short Name:
- J/A+A/641/A62
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Blazars are the rarest and most powerful active galactic nuclei, playing a crucial and growing role in today multi-frequency and multi-messenger astrophysics. They dominate the high-energy extragalactic sky and recently have been associated to high-energy astrophysical neutrinos, and they may be among the accelerators of the ultra-high energy cosmic rays. Current blazar catalogs, however, are incomplete and particularly depleted at low Galactic latitudes. We aim at augmenting the current blazar census starting from a sample of ALMA calibrators that provides more homogeneous sky coverage, especially at low Galactic latitudes, to build a catalog of blazar candidates that can provide candidate counterparts to unassociated gamma-ray sources and to sources of high-energy neutrino emission or ultra-high energy cosmic rays. Starting from the ALMA Calibrator Catalog we built a catalog of 1580 blazar candidates (ALMA Blazar Candidates) for which we collect multi-wavelength information, including Gaia photometric, parallax and proper motion data, SDSS and LAMOST photometric and spectral data, WISE photometric data, X-ray (Swift-XRT, Chandra-ACIS and XMM-Newton-EPIC) count-rates and spectra, and Fermi-LAT fluxes and spectral slopes. We also compared our ALMA Blazar Candidates with existing blazar catalogs, like 4FGL, 3HSP, WIBRaLS2 and the KDEBLLACS. The ALMA Blazar Candidates catalogue fills the lack of low Galactic latitude sources in current blazar catalogues. Cross-matching this catalog with Gaia DR2, SDSS DR12, LAMOST DR5, AllWISE and 4FGL catalogues we obtained 805, 295, 31, 1311 and 259 matches, respectively. ALMA Blazar Candidates are significantly dimmer than known blazars in Gaia g band, while the difference in the Gaia b-r colour between the two populations is less pronounced. Also, ALMA Blazar Candidates sources appear bluer in SDSS than known blazars, although with low statistical significance. Most ALMA Blazar Candidates classified as QSO and BL Lac fall into the SDSS colour regions of low redshift quasars, with some QSOs entering the regions of higher redshift quasars. We collected 110 optical spectra in SDSS DR12 and LAMOST DR5, which mostly classify the corresponding sources as QSO (98), while 12 sources resulted galactic objects. Regarding WISE colours, we found that ABC sources are significantly bluer than known blazars in the w2-w3 and w3-w4 colours. In X-rays we detected 173 ALMA Blazar Candidates, and we were able to extract a X-ray spectra for 92 of them. Our sources are on average similar in X-rays to known blazar in terms of count-rates and spectral slopes, implying that our sample is covering the same region of the blazar parameter space in this band. A comparison of gamma-ray properties shown that ALMA Blazar Candidates are on average dimmer, and their gamma-ray spectra are softer than known blazars, indicating a significant contribution of FSRQ sources. Making use of WISE colours, we classified 715 ALMA Blazar Candidates as candidate gamma-ray blazar of different classes. We built a new catalogue of 1580 candidate blazars with a rich multi-wavelength data-set, filling the lack of low Galactic latitude sources in current blazar catalogues. This will be particularly important to identify the source population of high energy neutrinos or ultra-high energy cosmic rays, or to verify the Gaia optical reference frame. In addition, ALMA Blazar Candidates can be investigated both through optical spectroscopic observation campaigns or through repeated photometric observations for variability studies. In this context, the data collected by the upcoming LSST surveys will provide a key tool to investigate the possible blazar nature of these sources.
