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4731. X-ray obs. of narrow- and broad-line Seyfert 1 gal.
ID:
ivo://CDS.VizieR/J/ApJ/896/95
Title:
X-ray obs. of narrow- and broad-line Seyfert 1 gal.
Short Name:
J/ApJ/896/95
Date:
03 Dec 2021 00:52:46
Publisher:
CDS
Description:
We present a detailed comparative systematic study using a sample of 221 narrow-line Seyfert 1 (NLSy1) galaxies in comparison to a redshift-matched sample of 154 broad-line Seyfert 1 (BLSy1) galaxies based on their observations using ROSAT and/or XMM-Newton in soft X-ray band (0.1-2.0keV). A homogeneous analysis is carried out to estimate their soft X-ray photon indices ({Gamma}_X_^s^) and its correlations with other parameters of nuclear activities such as Eddington ratios (REdd), bolometric luminosities (Lbol), black hole masses (MBH), and the widths of the broad component of H{beta} lines (FWHM(H{beta})). In our analysis, we found clear evidence of the difference in the {Gamma}_X_^s^ and R_Edd_ distributions among NLSy1 and BLSy1 galaxies, with steeper {Gamma}_X_^s^ and higher R_Edd_ for the former. Such a difference also exists in the spectral index distribution in hard X-ray ({Gamma}_X_^h^), based on the analysis of 53 NLSy1 and 46 BLSy1 galaxies in the 2-10keV energy band. The difference in REdd distributions does exist even after applying the average correction for the difference in the inclination angle of NLSy1 and BLSy1 galaxies. We also estimated R_Edd_, based on SED fitting of 34 NLSy1 and 30 BLSy1 galaxies over the 0.3-10keV energy band, and found that results are still consistent with REdd estimates based on the optical bolometric luminosity. Our analysis suggests that the higher REdd in NLSy1 is responsible for its steeper X-ray spectral slope compared to the BLSy1, consistent with the disk-corona model as proposed for the luminous AGNs.
4732. X-ray, optical and radio monitoring of 3C 111
ID:
ivo://CDS.VizieR/J/ApJ/734/43
Title:
X-ray, optical and radio monitoring of 3C 111
Short Name:
J/ApJ/734/43
Date:
21 Oct 2021
Publisher:
CDS
Description:
We present the results of extensive multi-frequency monitoring of the radio galaxy 3C 111 between 2004 and 2010 at X-ray (2.4-10keV), optical (R band), and radio (14.5, 37, and 230GHz) wave bands, as well as multi-epoch imaging with the Very Long Baseline Array (VLBA) at 43GHz. Over the six years of observation, significant dips in the X-ray light curve are followed by ejections of bright superluminal knots in the VLBA images. This shows a clear connection between the radiative state near the black hole, where the X-rays are produced, and events in the jet. The X-ray continuum flux and Fe line intensity are strongly correlated, with a time lag shorter than 90 days and consistent with zero.
4733. X-ray/optical observations of A8-G2V stars
ID:
ivo://CDS.VizieR/J/A+AS/128/29
Title:
X-ray/optical observations of A8-G2V stars
Short Name:
J/A+AS/128/29
Date:
21 Oct 2021
Publisher:
CDS
Description:
Table 1 lists the sample of 173 stars observed for this study. They are selected from the Bright Star Catalogue (Cat. <V/50>), with the following selection criteria: - Spectral type between A8 and G2; no spectral peculiarities noted; not double in spectral type classification (e.g., HR 32 with spectral type F2V+F6V is excluded); - Luminosity class V; - Right ascension between 0h and 2h, or between 14h and 24 h, declination south of +10 degrees (defining the region on the sky visible during the appointed observation times); - Binaries for which both components occurred in the BSC are excluded, if the separation is less than 10". Not listed are five stars for which no (Walraven photometric and ROSAT X-ray) data are available. These are HR 591, HR 5542, HR 6593, HR 8245 and HR 8735. Table 2 lists the Walraven photometric (VBLUW) data for all but four stars from Table 1. Also listed in Table 2 are the effective temperature, surface gravity and the reddening, as derived from comparison with theoretical colours. Table 5 lists the ROSAT All Sky Survey data for all but 11 stars from Table 1. For a description of the Walraven photometric system, see e.g. <GCPD/11>
4734. X-ray polarization predictions in blazars
ID:
ivo://CDS.VizieR/J/ApJ/880/29
Title:
X-ray polarization predictions in blazars
Short Name:
J/ApJ/880/29
Date:
21 Oct 2021
Publisher:
CDS
Description:
X-ray polarization should provide new probes of magnetic field geometry and acceleration physics near the base of blazar jets, but near-future missions will have limited sensitivity. We thus use existing lower energy data and X-ray variability measurements in the context of a basic synchro-Compton model to predict the X-ray polarization level and the probability of detection success for individual sources, listing the most attractive candidates for an Imaging X-ray Polarimetry Explorer campaign. We find that, as expected, several high-peak blazars such as Mrk 421 can be easily measured in 100ks exposures. Most low-peak sources should only be accessible to triggered campaigns during bright flares. Surprisingly, a few intermediate peak sources can have anomalously high X-ray polarization and thus are attractive targets.
4735. X-ray properties of 3 EDisCS galaxy clusters
ID:
ivo://CDS.VizieR/J/MNRAS/371/1777
Title:
X-ray properties of 3 EDisCS galaxy clusters
Short Name:
J/MNRAS/371/1777
Date:
21 Oct 2021
Publisher:
CDS
Description:
We present XMM-Newton observations of three optically selected z>0.6 clusters from the European Southern Observatory (ESO) Distant Cluster Survey (EDisCS), comprising the first results of a planned X-ray survey of the full EDisCS high-redshift sample. The EDisCS clusters were identified in the Las Campanas Distant Cluster Survey as surface brightness fluctuations in the optical sky and their masses and galaxy populations are well described by extensive photometric and spectroscopic observations. We detect two of the three clusters in the X-ray and place a firm upper limit on diffuse emission in the third cluster field. We are able to constrain the X-ray luminosity and temperature of the detected clusters and estimate their masses. We find that the X-ray properties of the detected EDisCS clusters are similar to those of X-ray-selected clusters of comparable mass and --- unlike other high-redshift, optically selected clusters --- are consistent with the T-sigma and L_X_-sigma relations determined from X-ray-selected clusters at low redshift. The X-ray determined mass estimates are generally consistent with those derived from weak-lensing and spectroscopic analyses. These preliminary results suggest that the novel method of optical selection used to construct the EDisCS catalogue may, like selection by X-ray luminosity, be well suited for identification of relaxed, high-redshift clusters whose intracluster medium is in place and stable by z=0.8.
4736. X-ray properties of NGC 300. I.
ID:
ivo://CDS.VizieR/J/A+A/443/103
Title:
X-ray properties of NGC 300. I.
Short Name:
J/A+A/443/103
Date:
21 Oct 2021
Publisher:
CDS
Description:
X-ray properties of NGC 300 point sources, extracted from 66ks of XMM-Newton data taken in 2000 December and 2001 January. A total of 163 sources were detected in the energy range of 0.3-6kev. We report on the global properties of the sources detected inside the D_25_ optical disk, such as the hardness ratio and X-ray fluxes, and on the properties of their optical counterparts found in B, V, and R images from the 2.2m MPG/ESO telescope. Furthermore, we cross-correlate the X-ray sources with SIMBAD, the USNO-A2.0 catalog, and radio catalogues.
4737. X-ray-selected normal galaxies
ID:
ivo://CDS.VizieR/J/MNRAS/360/782
Title:
X-ray-selected normal galaxies
Short Name:
J/MNRAS/360/782
Date:
21 Oct 2021
Publisher:
CDS
Description:
In this paper we estimate the local (z<0.22) X-ray luminosity function of 'normal' galaxies derived from the XMM-Newton Needles in the Haystack Survey. This is an on-going project that aims to identify X-ray-selected normal galaxies (i.e. non-AGN dominated) in the local Universe. We are using a total of 70 XMM-Newton fields covering an area of 11deg^2^ which overlap with the Sloan Digital Sky Survey Data Release 2. Normal galaxies are selected on the basis of their resolved optical light profile, their low X-ray-to-optical flux ratio [log(fx/fo)<-2] and soft X-ray colours. We find a total of 28 candidate normal galaxies to the 0.58keV band flux limit of 2x10^-15^erg/cm2/s. Optical spectra are available for most sources in our sample (82 per cent). These provide additional evidence that our sources are bona fide normal galaxies with X-ray emission coming from diffuse hot gas emission and/or X-ray binaries rather than a supermassive black hole.
4738. X-ray sources in NGC 4194 and NGC 7541
ID:
ivo://CDS.VizieR/J/ApJ/682/1020
Title:
X-ray sources in NGC 4194 and NGC 7541
Short Name:
J/ApJ/682/1020
Date:
21 Oct 2021
Publisher:
CDS
Description:
We examine the X-ray point-source population and 2-10keV luminosity for two galaxies with high star formation rates (SFRs), NGC 4194 and NGC 7541 and combined our results with a sample of galaxies with SFRs above 1M_{sun}_/yr.
4739. 126 X-rays sources around the cepheid {eta} Aql
ID:
ivo://CDS.VizieR/J/AJ/162/92
Title:
126 X-rays sources around the cepheid {eta} Aql
Short Name:
J/AJ/162/92
Date:
14 Mar 2022 07:02:20
Publisher:
CDS
Description:
X-ray bursts have recently been discovered in the Cepheids {delta}Cep and {beta}Dor modulated by the pulsation cycle. We have obtained an observation of the Cepheid {eta}Aql with the XMM-Newton satellite at the phase of maximum radius; the phase at which there is a burst of X-rays in {delta}Cep. No X-rays were seen from the Cepheid {eta}Aql at this phase, and the implications for Cepheid upper atmospheres are discussed. We have also used the combination of X-ray sources, as well as Gaia and 2MASS data, to search for a possible grouping around the young intermediate mass Cepheid. No indication of such a group was found.
4740. X-ray through NIR photometry of NGC 2617
ID:
ivo://CDS.VizieR/J/ApJ/788/48
Title:
X-ray through NIR photometry of NGC 2617
Short Name:
J/ApJ/788/48
Date:
21 Oct 2021
Publisher:
CDS
Description:
After the All-Sky Automated Survey for SuperNovae discovered a significant brightening of the inner region of NGC 2617, we began a ~70 day photometric and spectroscopic monitoring campaign from the X-ray through near-infrared (NIR) wavelengths. We report that NGC 2617 went through a dramatic outburst, during which its X-ray flux increased by over an order of magnitude followed by an increase of its optical/ultraviolet (UV) continuum flux by almost an order of magnitude. NGC 2617, classified as a Seyfert 1.8 galaxy in 2003, is now a Seyfert 1 due to the appearance of broad optical emission lines and a continuum blue bump. Such "changing look active galactic nuclei (AGNs)" are rare and provide us with important insights about AGN physics. Based on the H{beta} line width and the radius-luminosity relation, we estimate the mass of central black hole (BH) to be (4+/-1)x10^7^ M_{sun}_. When we cross-correlate the light curves, we find that the disk emission lags the X-rays, with the lag becoming longer as we move from the UV (2-3 days) to the NIR (6-9 days). Also, the NIR is more heavily temporally smoothed than the UV. This can largely be explained by a simple model of a thermally emitting thin disk around a BH of the estimated mass that is illuminated by the observed, variable X-ray fluxes.