- ID:
- ivo://CDS.VizieR/J/PAZh/37/924
- Title:
- 1RXS J073346.0+261933 light curve
- Short Name:
- J/PAZh/37/924
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- In the course of our search for the optical identifications of ROSAT X-ray sources, we have found a highly variable object with a very unusual behavior on long time scales, rare color indices, and a high X-ray-to-optical flux ratio. We present the archival light curve from the Catalina Sky Survey, optical spectroscopy from RTT150, and time-resolved photometry from the Astrotel-Caucasus telescope. The object appears to be a magnetic cataclysmic variable (a polar) with an orbital period P=3.20h.
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Search Results
- ID:
- ivo://CDS.VizieR/J/A+A/418/927
- Title:
- RXTE All-Sky Slew Survey catalog, |b|>10{deg}
- Short Name:
- J/A+A/418/927
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We report results of a serendipitous hard X-ray (3-20keV), nearly all-sky (|b|>10{deg}) survey based on RXTE/PCA observations performed during satellite reorientations in 1996-2002. The survey is 80% (90%) complete to a 4{sigma} limiting flux of ~1.8 (2.5)x10^-11^erg/s/cm^2^ in the 3-20keV band. The achieved sensitivity in the 3-8keV and 8-20keV subbands is similar to and an order of magnitude higher than that of the previously record HEAO-1 A1 and HEAO-1 A4 all-sky surveys, respectively. A combined 7x10^3^~sq.deg area of the sky is sampled to flux levels below 10^-11^erg/s/cm^2^ (3-20keV). In total 294 sources are detected and localized to better than ~1{deg}. 236 (80%) of these can be confidently associated with a known astrophysical object; another 22 likely result from the superposition of 2 or 3 closely located known sources. 35 detected sources remain unidentified, although for 12 of these we report a likely soft X-ray counterpart from the ROSAT all-sky survey bright source catalog. Of the reliably identified sources, 63 have local origin (Milky Way, LMC or SMC), 64 are clusters of galaxies and 100 are active galactic nuclei (AGN). The fact that the unidentified X-ray sources have hard spectra suggests that the majority of them are AGN, including highly obscured ones (N_H_>10^23^cm^-2^). For the first time we present a logN-logS diagram for extragalactic sources above 4x10^-12^erg/s/cm^2^ at 8-20keV.
- ID:
- ivo://CDS.VizieR/J/ApJ/736/138
- Title:
- RXTE observations of 4U 0142+61
- Short Name:
- J/ApJ/736/138
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- After at least six years of quiescence, anomalous X-ray pulsar (AXP) 4U 0142+61 entered an active phase in 2006 March that lasted several months and included six X-ray bursts as well as many changes in the persistent X-ray emission. The bursts, the first seen from this AXP in >11yr of Rossi X-Ray Timing Explorer monitoring, all occurred in the interval between 2006 April 6 and 2007 February 7. The burst durations ranged from (0.4-1.8)x10^3^s. The first five burst spectra are well modeled by blackbodies, with temperatures kT~2-9keV. However, the sixth burst had a complicated spectrum that is well characterized by a blackbody plus two emission features whose amplitude varied throughout the burst. The most prominent feature was at 14.0keV. Upon entry into the active phase, the pulsar showed a significant change in pulse morphology and a likely timing glitch. The glitch had a total frequency jump of (1.9+/-0.4)x10^-7^Hz, which recovered with a decay time of 17+/-2 days by more than the initial jump, implying a net spin-down of the pulsar. Within the framework of the magnetar model, the net spin-down of the star could be explained by regions of the superfluid that rotate slower than the rest. The bursts, flux enhancements, and pulse morphology changes can be explained as arising from crustal deformations due to stresses imposed by the highly twisted internal magnetic field. However, unlike other AXP outbursts, we cannot account for a major twist being implanted in the magnetosphere.
- ID:
- ivo://CDS.VizieR/J/AJ/129/2018
- Title:
- RXTE scaled fluxes of eta Car
- Short Name:
- J/AJ/129/2018
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present monitoring observations by the Rossi X-Ray Timing Explorer of the 2-10keV X-ray emission from the supermassive star {eta} Carinae from 1996 through late 2003. These data cover more than one of the stellar variability cycles in temporal detail and include especially detailed monitoring through two X-ray minima.
- ID:
- ivo://CDS.VizieR/J/A+A/361/1005
- Title:
- S10947 Aql photometry
- Short Name:
- J/A+A/361/1005
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- In the paper we report the discovery of a new variable star, called S10947 Aql, as the likely optical counterpart of RX J2009.8+1557. The optical variability pattern as well as the detected X-ray emission suggest that it is a chromospherically active binary of the RS Canum Venaticorum type. We discovered an occasional disappearance of the eclipsing minima as well as large variations in the eclipse amplitude. The present file contains the full set of measurements from the various types of the 705 photographic plates used in this investigation (note that the number of 709 given in the paper is wrong). The table file is sorted according to plate type which is listed in the first column. Given for each measurement are the Julian Date (corresponding to the time of mid-exposure) and the photographic magnitude. Uncertain measurements and/or upper limits are marked with a flag (4th column).
- ID:
- ivo://CDS.VizieR/J/AJ/132/1475
- Title:
- SDSS AGN from ROSAT PSPC
- Short Name:
- J/AJ/132/1475
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present a sample of 1744 type 1 active galactic nuclei (AGNs) from the Sloan Digital Sky Survey Data Release 4 (SDSS DR4) spectroscopic catalog with X-ray counterparts in the White-Giommi-Angelini Catalog (WGACAT) of ROSAT PSPC pointed observations. Of 1744 X-ray sources, 1410 (80.9%) are new AGN identifications. Of 4574 SDSS DR4 AGNs for which we found radio matches in the catalog of radio sources from the Faint Images of the Radio Sky at Twenty cm survey, 224 turned up in our sample of SDSS X-ray AGNs. The sample objects are given in a catalog that contains optical and X-ray parameters and supporting data, including redshifts; it also contains radio emission parameters where available. We illustrate the content of our catalog and its potential for AGN science by providing statistical relationships for the catalog data.
- ID:
- ivo://CDS.VizieR/J/AJ/128/1002
- Title:
- SDSS candidate type II quasars. II
- Short Name:
- J/AJ/128/1002
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Type II quasars are luminous active galactic nuclei (AGNs) whose central engines and broad-line regions are obscured by intervening material; such objects only recently have been discovered in appreciable numbers. We study the multiwavelength properties of 291 type II AGN candidates (0.3<z<0.8) selected on the basis of their optical emission-line properties from the spectroscopic database of the Sloan Digital Sky Survey (Cat. <J/AJ/126/2579>). This sample includes about 150 objects luminous enough to be classified as type II quasars. We matched the sample to the FIRST (20cm, Cat.<VIII/71>), IRAS (12-100{mu}m, Cat. <II/125>), 2MASS (JHK_s_, Cat. <II/246>), and RASS (0.1-2.4keV, Cat. <IX/29>) surveys. Roughly 10% of optically selected type II AGN candidates are radio-loud, comparable to the AGN population as a whole. About 40 objects are detected by IRAS at 60 and/or 100{mu}m, and the inferred mid/far-IR luminosities lie in the range L=10^45^-3x10^46^ergs/s. Average IR-to-[OIII]{lambda}5007 ratios of objects in our sample are consistent with those of other AGNs. Objects from our sample are 10 times less likely to have soft X-ray counterparts in RASS than type I AGNs with the same redshifts and [OIII]{lambda}5007 luminosities. The few type II AGN candidates from our sample that are detected by RASS have harder X-ray spectra than those of type I AGNs. The multiwavelength properties of the type II AGN candidates from our sample are consistent with their interpretation as powerful obscured AGNs.
- ID:
- ivo://CDS.VizieR/J/ApJ/819/154
- Title:
- SDSS-DR7 QSOs with X-ray and UV luminosities
- Short Name:
- J/ApJ/819/154
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The observed relation between the soft X-ray and the optical-ultraviolet emission in active galactic nuclei (AGNs) is nonlinear and it is usually parametrized as a dependence between the logarithm of the monochromatic luminosity at 2500{AA} and at 2keV. Previous investigations have found that the dispersion of this relation is rather high (~0.35-0.4 in log units), which may be caused by measurement uncertainties, variability, and intrinsic dispersion due to differences in the AGN physical properties (e.g., different accretion modes). We show that, once optically selected quasars with homogeneous SED and X-ray detection are selected, and dust reddened and/or gas obscured objects are not included, the measured dispersion drops to significantly lower values (i.e., ~0.21-0.24dex). We show that the residual dispersion is due to some extent to variability, and to remaining measurement uncertainties. Therefore, the real physical intrinsic dispersion should be <0.21dex. Such a tight relation, valid over four decades in luminosity, must be the manifestation of an intrinsic (and universal) physical relation between the disk, emitting the primary radiation, and the hot electron corona emitting X-rays.
- ID:
- ivo://CDS.VizieR/J/AJ/135/10
- Title:
- SDSS-DR4/RASS source matching
- Short Name:
- J/AJ/135/10
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The current view of galaxy formation holds that all massive galaxies harbor a massive black hole at their center, but that these black holes are not always in an actively accreting phase. X-ray emission is often used to identify accreting sources, but for galaxies that are not harboring quasars (low-luminosity active galaxies), the X-ray flux may be weak, or obscured by dust. To aid in the understanding of weakly accreting black holes in the local universe, a large sample of galaxies with X-ray detections is needed. We cross-match the ROSAT All Sky Survey (RASS) with galaxies from the Sloan Digital Sky Survey Data Release 4 (SDSS DR4) to create such a sample. Because of the high SDSS source density and large RASS positional errors, the cross-matched catalog is highly contaminated by random associations. We investigate the overlap of these surveys and provide a statistical test of the validity of RASS-SDSS galaxy cross-matches.
- ID:
- ivo://CDS.VizieR/J/ApJS/244/22
- Title:
- SDSS DR8 redMaPPer clusters Chandra follow-up
- Short Name:
- J/ApJS/244/22
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- In order to place constraints on cosmology through optical surveys of galaxy clusters, one must first understand the properties of those clusters. To this end, we introduce the Mass Analysis Tool for Chandra (MATCha), a pipeline that uses a parallellized algorithm to analyze archival Chandra data. MATCha simultaneously calculates X-ray temperatures and luminosities and performs centering measurements for hundreds of potential galaxy clusters using archival X-ray exposures. We run MATCha on the redMaPPer SDSS DR8 cluster catalog and use MATCha's output X-ray temperatures and luminosities to analyze the galaxy cluster temperature-richness, luminosity-richness, luminosity-temperature, and temperature-luminosity scaling relations. We detect 447 clusters and determine 246 r_2500_ temperatures across all redshifts. Within 0.1<z<0.35, we find that r_2500_ T_X_ scales with optical richness ({lambda}) as ln(k_B_T_X_/1.0keV)=(0.52+/-0.05)ln({lambda}/70)+(1.85+/-0.03) with an intrinsic scatter of 0.27+/-0.02 (1{sigma}). We investigate the distribution of offsets between the X-ray center and redMaPPer center within 0.1<z<0.35, finding that 68.3%+/-6.5% of clusters are well-centered. However, we find a broad tail of large offsets in this distribution, and we explore some of the causes of redMaPPer miscentering.